Spectral classification of medium-scale high-latitude F region plasma density irregularities

International Nuclear Information System (INIS)

Singh, M.; Rodriguez, P.; Szuszczewicz, E.P.; Sachs Freeman Associates, Bowie, MD)

1985-01-01

The high-latitude ionosphere represents a highly structured plasma. Rodriguez and Szuszczewicz (1984) reported a wide range of plasma density irregularities (150 km to 75 m) at high latitudes near 200 km. They have shown that the small-scale irregularities (7.5 km to 75 m) populated the dayside oval more often than the other phenomenological regions. It was suggested that in the lower F region the chemical recombination is fast enough to remove small-scale irregularities before convection can transport them large distances, leaving structured particle precipitation as the dominant source term for irregularities. The present paper provides the results of spectral analyses of pulsed plasma probe data collected in situ aboard the STP/S3-4 satellite during the period March-September 1978. A quantitative description of irregularity spectra in the high-latitude lower F region plasma density is given. 22 references

Irregular Applications: Architectures & Algorithms

Energy Technology Data Exchange (ETDEWEB)

Feo, John T.; Villa, Oreste; Tumeo, Antonino; Secchi, Simone

2012-02-06

Irregular applications are characterized by irregular data structures, control and communication patterns. Novel irregular high performance applications which deal with large data sets and require have recently appeared. Unfortunately, current high performance systems and software infrastructures executes irregular algorithms poorly. Only coordinated efforts by end user, area specialists and computer scientists that consider both the architecture and the software stack may be able to provide solutions to the challenges of modern irregular applications.

The Particle Shape of WC Governing the Fracture Mechanism of Particle Reinforced Iron Matrix Composites.

Science.gov (United States)

Li, Zulai; Wang, Pengfei; Shan, Quan; Jiang, Yehua; Wei, He; Tan, Jun

2018-06-11

In this work, tungsten carbide particles (WC p , spherical and irregular particles)-reinforced iron matrix composites were manufactured utilizing a liquid sintering technique. The mechanical properties and the fracture mechanism of WC p /iron matrix composites were investigated theoretically and experimentally. The crack schematic diagram and fracture simulation diagram of WC p /iron matrix composites were summarized, indicating that the micro-crack was initiated both from the interface for spherical and irregular WC p /iron matrix composites. However, irregular WC p had a tendency to form spherical WC p . The micro-cracks then expanded to a wide macro-crack at the interface, leading to a final failure of the composites. In comparison with the spherical WC p , the irregular WC p were prone to break due to the stress concentration resulting in being prone to generating brittle cracking. The study on the fracture mechanisms of WC p /iron matrix composites might provide a theoretical guidance for the design and engineering application of particle reinforced composites.

Experimental investigation of coolability behaviour of irregularly shaped particulate debris bed

International Nuclear Information System (INIS)

Kulkarni, P.P.; Rashid, M.; Kulenovic, R.; Nayak, A.K.

2010-01-01

In case of a severe nuclear reactor accident, the core can melt and form a particulate debris bed in the lower plenum of the reactor pressure vessel (RPV). Due to the decay heat, the particle bed, if not cooled properly, can cause failure of the RPV. In order to avoid further propagation of the accident, complete coolability of the debris bed is necessary. For that, understanding of various phenomena taking place during the quenching is important. In the frame of the reactor safety research, fundamental experiments on the coolability of debris beds are carried out at IKE with the test facility 'DEBRIS'. In the present paper, the boiling and dry-out experimental results on a particle bed with irregularly shaped particles mixed with stainless steel balls have been reported. The pressure drops and dry-out heat fluxes of the irregular-particle bed are very similar to those for the single-sized 3 mm spheres bed, despite the fact that the irregular-particle bed is composed of particles with equivalent diameters ranging from 2 to 10 mm. Under top-flooding conditions, the pressure gradients are all smaller than the hydrostatic pressure gradient of water, indicating an important role of the counter-current interfacial drag force. For bottom-flooding with a liquid inflow velocity higher than about 2.7 mm/s, the pressure gradient generally increases consistently with the vapour velocity and the fluid-particle drag becomes important. The system pressures (1 and 3 bar) have negligible effects on qualitative behaviour of the pressure gradients. The coolability of debris beds is mainly limited by the counter-current flooding limit (CCFL) even under bottom-flooding conditions with low flow rates. The system pressure and the flow rate are found to have a distinct effect on the dry-out heat flux. Different classical models have been used to predict the pressure drop characteristics and the dry-out heat flux (DHF). Comparisons are made among the models and experimental results for

Shape evolution of a melting nonspherical particle

Science.gov (United States)

Kintea, Daniel M.; Hauk, Tobias; Roisman, Ilia V.; Tropea, Cameron

2015-09-01

In this study melting of irregular ice crystals was observed in an acoustic levitator. The evolution of the particle shape is captured using a high-speed video system. Several typical phenomena have been discovered: change of the particle shape, appearance of a capillary flow of the melted liquid on the particle surface leading to liquid collection at the particle midsection (where the interface curvature is smallest), and appearance of sharp cusps at the particle tips. No such phenomena can be observed during melting of spherical particles. An approximate theoretical model is developed which accounts for the main physical phenomena associated with melting of an irregular particle. The agreement between the theoretical predictions for the melting time, for the evolution of the particle shape, and the corresponding experimental data is rather good.

Random packing of digitized particles

NARCIS (Netherlands)

Korte, de A.C.J.; Brouwers, H.J.H.

2013-01-01

The random packing of regularly and irregularly shaped particles has been studied extensively. Within this paper, packing is studied from the perspective of digitized particles. These digitized particles are developed for and used in cellular automata systems, which are employed for the simple

Random packing of digitized particles

NARCIS (Netherlands)

de Korte, A.C.J.; Brouwers, Jos

2012-01-01

The random packing of regularly and irregularly shaped particles has been studied extensively. Within this paper, packing is studied from the perspective of digitized particles. These digitized particles are developed for and used in cellular automata systems, which are employed for the simple

Star Formation in Irregular Galaxies.

Science.gov (United States)

Hunter, Deidre; Wolff, Sidney

1985-01-01

Examines mechanisms of how stars are formed in irregular galaxies. Formation in giant irregular galaxies, formation in dwarf irregular galaxies, and comparisons with larger star-forming regions found in spiral galaxies are considered separately. (JN)

Plasma Irregularity Production in the Polar Cap F-Region Ionosphere

Science.gov (United States)

Lamarche, Leslie

Plasma in the Earth's ionosphere is highly irregular on scales ranging between a few centimeters and hundreds of kilometers. Small-scale irregularities or plasma waves can scatter radio waves resulting in a loss of signal for navigation and communication networks. The polar region is particularly susceptible to strong disturbances due to its direct connection with the Sun's magnetic field and energetic particles. In this thesis, factors that contribute to the production of decameter-scale plasma irregularities in the polar F region ionosphere are investigated. Both global and local control of irregularity production are studied, i.e. we consider global solar control through solar illumination and solar wind as well as much more local control by plasma density gradients and convection electric field. In the first experimental study, solar control of irregularity production is investigated using the Super Dual Auroral Radar Network (SuperDARN) radar at McMurdo, Antarctica. The occurrence trends for irregularities are analyzed statistically and a model is developed that describes the location of radar echoes within the radar's field-of-view. The trends are explained through variations in background plasma density with solar illumination affecting radar beam propagation. However, it is found that the irregularity occurrence during the night is higher than expected from ray tracing simulations based on a standard ionospheric density model. The high occurrence at night implies an additional source of plasma density and it is proposed that large-scale density enhancements called polar patches may be the source of this density. Additionally, occurrence maximizes around the terminator due to different competing irregularity production processes that favor a more or less sunlit ionosphere. The second study is concerned with modeling irregularity characteristics near a large-scale density gradient reversal, such as those expected near polar patches, with a particular focus on

Structure of irregular galactic magnetic fields determined on the basis of cosmic ray measurements

International Nuclear Information System (INIS)

Somogyi, A.

1975-02-01

In the paper a method is described to determine the structural composition of random galactic fields on the basis of cosmic ray measurements, down to structures with characteristic length of the order of 0.001 to 1 pc. Assuming the diffusion mean free path of the particles to be independent of particle energy the spectral index of magnetic irregularities is estimated to be -(1.0+-0.5). The linear size of the confinement volume is found to be almost independent of particle energy. (Sz.Z.)

Method for producing ceramic particles and agglomerates

Science.gov (United States)

Phillips, Jonathan; Gleiman, Seth S.; Chen, Chun-Ku

2001-01-01

A method for generating spherical and irregularly shaped dense particles of ceramic oxides having a controlled particle size and particle size distribution. An aerosol containing precursor particles of oxide ceramics is directed into a plasma. As the particles flow through the hot zone of the plasma, they melt, collide, and join to form larger particles. If these larger particles remain in the hot zone, they continue melting and acquire a spherical shape that is retained after they exit the hot zone, cool down, and solidify. If they exit the hot zone before melting completely, their irregular shape persists and agglomerates are produced. The size and size distribution of the dense product particles can be controlled by adjusting several parameters, the most important in the case of powder precursors appears to be the density of powder in the aerosol stream that enters the plasma hot zone. This suggests that particle collision rate is responsible for determining ultimate size of the resulting sphere or agglomerate. Other parameters, particularly the gas flow rates and the microwave power, are also adjusted to control the particle size distribution.

Stability of a Bose Condensate in the presence of regular and irregular potentials

International Nuclear Information System (INIS)

Gunn, J.M.F.

1984-05-01

The stability of an interacting Bose Condensate in the presence of a periodic potential is discussed. The condensate is destroyed if the potential is sufficiently strong, for certain densities of particles. Secondly irregular potentials of two types are considered: a dilute set of ''defect'' potentials in an otherwise periodic potential; and a highly irregular potential. In the first case, if the defect potential is sufficiently strong, the condensate is found to have a depletion which varies with the concentration of the defects. In the latter case it is argued that the condensate is totally destroyed. The consequences of the theory for experiments on 4 He films are discussed, and some new experiments proposed. (author)

Irregular Migrants and the Law

OpenAIRE

Kassim, Azizah; Mat Zin, Ragayah Hj.

2013-01-01

This paper examines Malaysia`s policy on irregular migrants and its implementation, and discusses its impact. A survey and interview covering 404 respondents was conducted between July 2010 and June 2011 to ascertain the real situations surrounding irregular migrants in Malaysia, which is one of the major host countries of international migrants from developing nations. The policy on foreign workers was formulated in the mid-1980s to deal with the large number of irregular migrants and their ...

Irregular Magnetic Fields and Energetic Particles near the Termination Shock

International Nuclear Information System (INIS)

Giacalone, J.; Jokipii, J. R.

2004-01-01

The physics of magnetic field-line meandering and the associated energetic-particle transport in the outer heliosphere is discussed. We assume that the heliospheric magnetic field, which is frozen into the solar-wind plasma, is composed of both an average and random component. The power in the random component is dominated by spatial scales that are very large (by a few orders of magnitude) compared to the shock thickness. The results from recent numerical simulations are presented. They reveal a number of characteristics which may be related to recent Voyager 1 observations of energetic particles and fields. For instance, low-energy (tens of keV) particles are seen well upstream of the shock that also have large pitch-angle anisotropies. Furthermore, low-energy particles are readily accelerated by the shock, even though their mean-free paths are very large compared to their gyroradii. When averaging over the entire system, the downstream spectra are qualitatively consistent with the theory of diffusive shock acceleration

Comparison of models and measurements of angle-resolved scatter from irregular aerosols

International Nuclear Information System (INIS)

Milstein, Adam B.; Richardson, Jonathan M.

2015-01-01

We have developed and validated a method for modeling the elastic scattering properties of biological and inert aerosols of irregular shape at near- and mid-wave infrared wavelengths. The method, based on Gaussian random particles, calculates the ensemble-average optical cross section and Mueller scattering matrix, using the measured aerodynamic size distribution and previously-reported refractive index as inputs. The utility of the Gaussian particle model is that it is controlled by only two parameters (σ and Γ) which we have optimized such that the model best reproduces the full angle-resolved Mueller scattering matrices measured at λ=1.55 µm in the Standoff Aerosol Active Signature Testbed (SAAST). The method has been applied to wet-generated singlet biological spore samples, dry-generated biological spore clusters, and kaolin. The scattering computation is performed using the Discrete Dipole Approximation (DDA), which requires significant computational resources, and is thus implemented on LLGrid, a large parallel grid computer. For the cases presented, the best fit Gaussian particle model is in good qualitative correspondence with microscopy images of the corresponding class of particles. The measured and computed cross sections agree well within a factor of two overall, with certain cases bearing closer correspondence. In particular, the DDA reproduces the shape of the measured scatter function more accurately than Mie predictions. The DDA-computed depolarization factors are also in good agreement with measurement. - Highlights: • We model elastic scattering of biological and inert aerosols of irregular shape. • We calculate cross sections and Mueller matrix using random particle shape model. • Scatter models employ refractive index and measured size distribution as inputs. • Discrete dipole approximation (DDA) with parallelization enables model calculations. • DDA-modeled cross section and Mueller matrix agree well with measurements at 1.55 μm

Strategic Analysis of Irregular Warfare

Science.gov (United States)

2010-03-01

the same mathematical equations used by Lanchester .10 Irregular Warfare Theory and Doctrine It is time to develop new analytical methods and models...basis on which to build, similar to what Lanchester provided almost 100 years ago. Figure 9 portrays both Lanchester’s approach and an irregular 17

Irregular Migration in Jordan, 1995-2007

OpenAIRE

AROURI, Fathi A.

2008-01-01

Euro-Mediterranean Consortium for Applied Research on International Migration (CARIM) This paper tackles the question of irregular migration in Jordan through its four main aspects. The first concerns irregular labour migrants and has been approached by using figures showing the socio-economic profile of non Jordanians working in Jordan and, additionally, unemployment in Jordan. This is done by assuming close similarities between legal and irregular labour migrants. The second is an attemp...

Fitting Irregular Shape Figures into Irregular Shape Areas for the Nesting Problem in the Leather Industry

Directory of Open Access Journals (Sweden)

Guevara-Palma Luis

2015-01-01

Full Text Available The nesting problem of irregular shapes within irregular areas has been studied from several approaches due to their application in different industries. The particular case of cutting leather involves several restrictions that add complexity to this problem, it is necessary to generate products that comply with the quality required by customers This paper presents a methodology for the accommodation of irregular shapes in an irregular area (leather considering the constraints set by the footwear industry, and the results of this methodology when applied by a computer system. The scope of the system is to develop a working prototype that operates under the guidelines of a commercial production line of a sponsor company. Preliminary results got a reduction of 70% of processing time and improvement of 5% to 7% of the area usage when compared with manual accommodation.

Nanodiamond particles forming photonic structures

International Nuclear Information System (INIS)

Grichko, Varvara; Tyler, Talmage; Grishko, Victor I; Shenderova, Olga

2008-01-01

Colloid suspensions of irregularly shaped, highly charged detonation nanodiamond particles are found to have unexpected optical properties, similar to those of photonic crystals. This finding is all the more surprising since the particles used in this work are far more polydisperse than those typically forming photonic crystals. Intensely iridescent structures have been fabricated using the centrifugation of aqueous suspensions of nanodiamonds

Nanodiamond particles forming photonic structures

Energy Technology Data Exchange (ETDEWEB)

Grichko, Varvara; Tyler, Talmage; Grishko, Victor I; Shenderova, Olga [International Technology Center, 8100 Brownleigh Drive, Suite 120, Raleigh, NC 27617 (United States)], E-mail: oshenderova@itc-inc.org

2008-06-04

Colloid suspensions of irregularly shaped, highly charged detonation nanodiamond particles are found to have unexpected optical properties, similar to those of photonic crystals. This finding is all the more surprising since the particles used in this work are far more polydisperse than those typically forming photonic crystals. Intensely iridescent structures have been fabricated using the centrifugation of aqueous suspensions of nanodiamonds.

Dispersion of Bed Load Particles

OpenAIRE

SAWAI, Kenji

1987-01-01

The motion of bed load particles is so irregular that they disperse remarkably with time.In this study, some flume tests using painted tracer particles were carried out, in which thedispersive property of tracers changed variously with sediment feed rate.In analysing this process, a stochastic simulation model is proposed where it is discussedabout the degree of exposure of individual particle near the bed surface and about the variationof its pick up rate. The exponential distribution of ste...

Legal aspects of the EU policy on irregular immigration

Directory of Open Access Journals (Sweden)

Voinikov Vadim

2015-12-01

Full Text Available This article addresses the issues pertaining to the adoption and development of legislation on irregular migration in the context of uncontrolled growth in the number of immigrants from North Africa and the Middle East to the EU. The article attempts at studying the EU legislation on irregular migration, classifying it, and analysing the prospects of EU migration legislation in the light of an increase in irregular immigration into the EU. The author systematises, classifies the current EU legislation on irregular immigration, and analyses the conditions, in which this legislation was developed. Using the legislation analysis method, the author proposes the following system of EU legislation on irregular immigration: rules preventing assistance to irregular immigration, rules preventing employment of irregular immigrants, rules on the return of irregular migrants and readmission, rules on border control, and rules on collaboration with third countries. The author pays special attention to analysing the current state of irregular immigration to the EU, which was dubbed the ‘greatest migration crisis in Europe’. The conclusion is that the European Union succeeded in the development of pioneering legislation on irregular immigration, which can serve as the basis for reception by other states. However, changes in the political and economic situation in the EU’s southern borderlands made the current legal mechanisms incapable of withstanding new threats. It necessitates a radical reform of the legislation on irregular immigration.

Irregular menstruation according to occupational status.

Science.gov (United States)

Kwak, Yeunhee; Kim, Yoonjung

2017-07-06

This cross-sectional study explored associations of irregular menstruation with occupational characteristics, using secondary analyses of data from 4,731 women aged 19-54 years, collected from a nationally representative sample, the Korea National Health and Nutrition Examination Survey-V during 2010-2012. The associations between irregular menstruation and occupation were explored using multiple logistic regression. Compared to non-manual workers, service/sales workers had a greater odds of irregular menstruation (adjusted odds ratio [aOR]: 1.44; 95percent confidence interval [CI]: 1.04-1.99) as did manual workers and unemployed women (aOR: 1.56; 95percent CI: 1.10-2.22, aOR: 1.46; 95percent CI: 1.14-1.89, respectively). Compared to regular workers, temporary workers and unemployed women had aORs of 1.52 (95percent CI: 1.08-2.13) and 1.33 (95percent CI: 1.05-1.69), respectively. Also, when compared to full-time workers, part-time workers and unemployed women had greater odds of irregular menstruation (aOR: 1.41; 95percent CI: 1.00-2.00 and aOR: 1.29; 95percent CI: 1.03-1.63, respectively). Furthermore, compared to daytime workers, shift workers and unemployed women had greater odds irregular menstruation (aOR: 1.39; 95percent CI: 1.03-1.88 and aOR: 1.28; 95percent CI: 1.04-1.59, respectively). Women with these occupational characteristics should be screened for early diagnosis and intervention for irregular menstruation.

Irregular conformal block, spectral curve and flow equations

International Nuclear Information System (INIS)

Choi, Sang Kwan; Rim, Chaiho; Zhang, Hong

2016-01-01

Irregular conformal block is motivated by the Argyres-Douglas type of N=2 super conformal gauge theory. We investigate the classical/NS limit of irregular conformal block using the spectral curve on a Riemann surface with irregular punctures, which is equivalent to the loop equation of irregular matrix model. The spectral curve is reduced to the second order (Virasoro symmetry, SU(2) for the gauge theory) and third order (W_3 symmetry, SU(3)) differential equations of a polynomial with finite degree. The conformal and W symmetry generate the flow equations in the spectral curve and determine the irregular conformal block, hence the partition function of the Argyres-Douglas theory ala AGT conjecture.

16 CFR 501.6 - Cellulose sponges, irregular dimensions.

Science.gov (United States)

2010-01-01

... 16 Commercial Practices 1 2010-01-01 2010-01-01 false Cellulose sponges, irregular dimensions. 501... REQUIREMENTS AND PROHIBITIONS UNDER PART 500 § 501.6 Cellulose sponges, irregular dimensions. Variety packages of cellulose sponges of irregular dimensions, are exempted from the requirements of § 500.25 of this...

Ethical issues in irregular migration research

NARCIS (Netherlands)

Duvell, F.; Triandafyllidou, A.; Vollmer, B.

2008-01-01

This paper is concerned with the ethical issues arising for researchers engaged in the study of irregular migration. Irregular migration is by definition an elusive phenomenon as it takes place in violation of the law and at the margins of society. This very nature of the phenomenon raises important

Scattering of light by nonspherical particles

International Nuclear Information System (INIS)

Coulson, K.L.

1985-12-01

Methods of computing scattering by non-spherical particles are reviewed for the Mie theory, the Rayleigh-Gans approximation, the geometric optics method, the extended boundary condition method, the anamalous diffraction, the suppression of resonances, the statistical approach, the expansion of vector wave equations in spheroidal coordinates, and the semi-emperical theory of Pollack and Cuzzi. The results of computations for nonspherical particles are compared for prolate and oblate spheroids, homogeneous sphere with holes, rough particles made of stacked cylinders, irregular particles of various shapes, and particles of carbonaceous smokes. Conclusions are presented in the context of nuclear winter

Influence of the particle morphology on the Cold Gas Spray deposition behaviour of titanium on aluminum light alloys

International Nuclear Information System (INIS)

Cinca, N.; Rebled, J.M.; Estradé, S.; Peiró, F.; Fernández, J.; Guilemany, J.M.

2013-01-01

Highlights: ► Study of the particle–substrate and particle–particle interfaces in the cold spray process. ► Use of irregular feedstock particles whereas normally FIB studies have been undergone for spherical particles. ► Deep Transmission Electron Microscopy characterization of the interfaces and within the particle. -- Abstract: The present work evaluates the deposition behaviour of irregular titanium powder particles impinged by Cold Gas Spraying onto an aluminium 7075-T6 alloy substrate. The influence of their irregular shape on the bonding phenomena, in particle–substrate and particle–particle interfaces are discussed in view of Transmission Electron Microscopy examinations of a Focused Ion Beam lift-out prepared sample. Key aspects will be the jetting-out, the occurrence of oxide layers and grain size refinement. Different structural morphologies could be featured; at the particle–substrate interface, both the aluminium alloy and the titanium side exhibit recrystallization. Titanium particles in intimate contact in small agglomerates during deposition, on the other hand, show grain refinement at their interfaces whereas the original structure is maintained outside those boundaries

Locating irregularly shaped clusters of infection intensity

Directory of Open Access Journals (Sweden)

Niko Yiannakoulias

2010-05-01

Full Text Available Patterns of disease may take on irregular geographic shapes, especially when features of the physical environment influence risk. Identifying these patterns can be important for planning, and also identifying new environmental or social factors associated with high or low risk of illness. Until recently, cluster detection methods were limited in their ability to detect irregular spatial patterns, and limited to finding clusters that were roughly circular in shape. This approach has less power to detect irregularly-shaped, yet important spatial anomalies, particularly at high spatial resolutions. We employ a new method of finding irregularly-shaped spatial clusters at micro-geographical scales using both simulated and real data on Schistosoma mansoni and hookworm infection intensities. This method, which we refer to as the “greedy growth scan”, is a modification of the spatial scan method for cluster detection. Real data are based on samples of hookworm and S. mansoni from Kitengei, Makueni district, Kenya. Our analysis of simulated data shows how methods able to find irregular shapes are more likely to identify clusters along rivers than methods constrained to fixed geometries. Our analysis of infection intensity identifies two small areas within the study region in which infection intensity is elevated, possibly due to local features of the physical or social environment. Collectively, our results show that the “greedy growth scan” is a suitable method for exploratory geographical analysis of infection intensity data when irregular shapes are suspected, especially at micro-geographical scales.

Detecting chaos in irregularly sampled time series.

Science.gov (United States)

Kulp, C W

2013-09-01

Recently, Wiebe and Virgin [Chaos 22, 013136 (2012)] developed an algorithm which detects chaos by analyzing a time series' power spectrum which is computed using the Discrete Fourier Transform (DFT). Their algorithm, like other time series characterization algorithms, requires that the time series be regularly sampled. Real-world data, however, are often irregularly sampled, thus, making the detection of chaotic behavior difficult or impossible with those methods. In this paper, a characterization algorithm is presented, which effectively detects chaos in irregularly sampled time series. The work presented here is a modification of Wiebe and Virgin's algorithm and uses the Lomb-Scargle Periodogram (LSP) to compute a series' power spectrum instead of the DFT. The DFT is not appropriate for irregularly sampled time series. However, the LSP is capable of computing the frequency content of irregularly sampled data. Furthermore, a new method of analyzing the power spectrum is developed, which can be useful for differentiating between chaotic and non-chaotic behavior. The new characterization algorithm is successfully applied to irregularly sampled data generated by a model as well as data consisting of observations of variable stars.

Fatigue damage estimation using irregularity factor. First report, irregularity factor calculations for narrow and broadband random time histories

Science.gov (United States)

Susuki, I.

1981-11-01

The results of an analysis of the irregularity factors of stationary and Gaussian random processes which are generated by filtering the output of a pure or a band-limited white noise are presented. An ideal band pass filter, a trapezoidal filter, and a Butterworth type band pass filter were examined. It was found that the values of the irregularity factors were approximately equal among these filters if only the end-slopes were the same rates. As the band width of filters increases, irregularity factors increase monotonically and approach the respective constant values depending on the end-slopes. This implies that the noise characteristics relevant to the fatigue damage such as statistical aspects of the height of the rise and fall or the distribution of the peak values are not changed for a broad band random time history. It was also found that the effect of band limitation of input white noise on irregularity factors is negligibly small.

On irregularity strength of disjoint union of friendship graphs

Directory of Open Access Journals (Sweden)

Ali Ahmad

2013-11-01

Full Text Available We investigate the vertex total and edge total modication of the well-known irregularity strength of graphs. We have determined the exact values of the total vertex irregularity strength and the total edge irregularity strength of a disjoint union of friendship graphs.

Regular and stochastic particle motion in plasma dynamics

International Nuclear Information System (INIS)

Kaufman, A.N.

1979-08-01

A Hamiltonian formalism is presented for the study of charged-particle trajectories in the self-consistent field of the particles. The intention is to develop a general approach to plasma dynamics. Transformations of phase-space variables are used to separate out the regular, adiabatic motion from the irregular, stochastic trajectories. Several new techniques are included in this presentation

Poincaré surfaces of section around a 3D irregular body: the case of asteroid 4179 Toutatis

Science.gov (United States)

Borderes-Motta, G.; Winter, O. C.

2018-02-01

In general, small bodies of the Solar system, e.g. asteroids and comets, have a very irregular shape. This feature affects significantly the gravitational potential around these irregular bodies, which hinders dynamical studies. The Poincaré surface of section technique is often used to look for stable and chaotic regions in two-dimensional dynamic cases. In this work, we show that this tool can be useful for exploring the surroundings of irregular bodies such as the asteroid 4179 Toutatis. Considering a rotating system with a particle, under the effect of the gravitational field computed three dimensionally, we define a plane in the phase space to build the Poincaré surface of section. Despite the extra dimension, the sections created allow us to find trajectories and classify their stabilities. Thus, we have also been able to map stable and chaotic regions, as well as to find correlations between those regions and the contribution of the third dimension of the system to the trajectory dynamics as well. As examples, we show details of periodic (resonant or not) and quasi-periodic trajectories.

Characteristics of ionospheric irregularities causing scintillations at VHF/UHF

International Nuclear Information System (INIS)

Vats, H.O.; Deshpande, M.R.; Rastogi, R.G.

1978-01-01

Some properties of ionization irregularities using amplitude scintillation records of radio beacons from ATS-6 (phase II) at Ootacamund, India have been investigated. For the estimation of scale-size and strength of the irregularities a simple diffraction model has been used which explains only weak and moderate equatorial scintillation observations. It was found that the scale sizes of day time E-region irregularities are smaller than those in the F-region during night time in addition, irregularities are generated initially at large scale sizes which later break up into smaller scale sizes

Morphology of bone particles after harvesting with 4 different devices.

Science.gov (United States)

Papadimitriou, Dimitrios E V; Schmidt, Erich C; Caton, Jack G; Romanos, Georgios E

2013-04-01

Autogenous bone is routinely used for regeneration of osseous defects around teeth and implants, and different instruments are available for bone harvesting. The purpose of this study was to describe the morphology of bone particles after harvesting with 4 different instruments. Bone particles were harvested from fresh cow ribs with 2 different types of back action chisels, a safescraper and a sonic device. The samples were examined morphologically using light microscopy and scanning electron microscopy. The bone particles after the back action chisel I had an appearance similar to "pencil shavings." With the back action chisel II, they were like thin paper with an "accordion bellows" appearance. After removal with the safescraper, they had an irregular shape (with an irregular surface) resembling "crushed stone." Finally, the appearance of the bone particles obtained with the sonic device was homogenous, condensed and continuous, and had a "seaweed" appearance. Harvesting of bone particles with 4 different devices produce distinctly difference sizes and shapes, which may influence the results of grafting procedures.

14 CFR 135.65 - Reporting mechanical irregularities.

Science.gov (United States)

2010-01-01

... irregularities and their correction. (b) The pilot in command shall enter or have entered in the aircraft maintenance log each mechanical irregularity that comes to the pilot's attention during flight time. Before each flight, the pilot in command shall, if the pilot does not already know, determine the status of...

Orbital and Collisional Evolution of the Irregular Satellites

Science.gov (United States)

Nesvorný, David; Alvarellos, Jose L. A.; Dones, Luke; Levison, Harold F.

2003-07-01

The irregular moons of the Jovian planets are a puzzling part of the solar system inventory. Unlike regular satellites, the irregular moons revolve around planets at large distances in tilted and eccentric orbits. Their origin, which is intimately linked with the origin of the planets themselves, is yet to be explained. Here we report a study of the orbital and collisional evolution of the irregular satellites from times after their formation to the present epoch. The purpose of this study is to find out the features of the observed irregular moons that can be attributed to this evolution and separate them from signatures of the formation process. We numerically integrated ~60,000 test satellite orbits to map orbital locations that are stable on long time intervals. We found that the orbits highly inclined to the ecliptic are unstable due to the effect of the Kozai resonance, which radially stretches them so that satellites either escape from the Hill sphere, collide with massive inner moons, or impact the parent planet. We also found that prograde satellite orbits with large semimajor axes are unstable due to the effect of the evection resonance, which locks the orbit's apocenter to the apparent motion of the Sun around the parent planet. In such a resonance, the effect of solar tides on a resonant moon accumulates at each apocenter passage of the moon, which causes a radially outward drift of its orbital apocenter; once close to the Hill sphere, the moon escapes. By contrast, retrograde moons with large orbital semimajor axes are long-lived. We have developed an analytic model of the distant satellite orbits and used it to explain the results of our numerical experiments. In particular, we analytically studied the effect of the Kozai resonance. We numerically integrated the orbits of the 50 irregular moons (known by 2002 August 16) for 108 yr. All orbits were stable on this time interval and did not show any macroscopic variations that would indicate

Decomposing Oriented Graphs into Six Locally Irregular Oriented Graphs

DEFF Research Database (Denmark)

Bensmail, Julien; Renault, Gabriel

2016-01-01

An undirected graph G is locally irregular if every two of its adjacent vertices have distinct degrees. We say that G is decomposable into k locally irregular graphs if there exists a partition E1∪E2∪⋯∪Ek of the edge set E(G) such that each Ei induces a locally irregular graph. It was recently co...

Design Optimization of Irregular Cellular Structure for Additive Manufacturing

Science.gov (United States)

Song, Guo-Hua; Jing, Shi-Kai; Zhao, Fang-Lei; Wang, Ye-Dong; Xing, Hao; Zhou, Jing-Tao

2017-09-01

Irregularcellular structurehas great potential to be considered in light-weight design field. However, the research on optimizing irregular cellular structures has not yet been reporteddue to the difficulties in their modeling technology. Based on the variable density topology optimization theory, an efficient method for optimizing the topology of irregular cellular structures fabricated through additive manufacturing processes is proposed. The proposed method utilizes tangent circles to automatically generate the main outline of irregular cellular structure. The topological layoutof each cellstructure is optimized using the relative density informationobtained from the proposed modified SIMP method. A mapping relationship between cell structure and relative densityelement is builtto determine the diameter of each cell structure. The results show that the irregular cellular structure can be optimized with the proposed method. The results of simulation and experimental test are similar for irregular cellular structure, which indicate that the maximum deformation value obtained using the modified Solid Isotropic Microstructures with Penalization (SIMP) approach is lower 5.4×10-5 mm than that using the SIMP approach under the same under the same external load. The proposed research provides the instruction to design the other irregular cellular structure.

MPPT-Based Control Algorithm for PV System Using iteration-PSO under Irregular shadow Conditions

Directory of Open Access Journals (Sweden)

M. Abdulkadir

2017-02-01

Full Text Available The conventional maximum power point tracking (MPPT techniques can hardly track the global maximum power point (GMPP because the power-voltage characteristics of photovoltaic (PV exhibit multiple local peaks in irregular shadow, and therefore easily fall into the local maximum power point. These conditions make it very challenging, and to tackle this deficiency, an efficient Iteration Particle Swarm Optimization (IPSO has been developed to improve the quality of solution and convergence speed of the traditional PSO, so that it can effectively track the GMPP under irregular shadow conditions. This proposed technique has such advantages as simple structure, fast response and strong robustness, and convenient implementation. It is applied to MPPT control of PV system in irregular shadow to solve the problem of multi-peak optimization in partial shadow. In order to verify the rationality of the proposed algorithm, however, recently the dynamic MPPT performance under varying irradiance conditions has been given utmost attention to the PV society. As the European standard EN 50530 which defines the recommended varying irradiance profiles, was released lately, the corresponding researchers have been required to improve the dynamic MPPT performance. This paper tried to evaluate the dynamic MPPT performance using EN 50530 standard. The simulation results show that iterative-PSO method can fast track the global MPP, increase tracking speed and higher dynamic MPPT efficiency under EN 50530 than the conventional PSO.

Analysis of External Surface Irregularities on Fukushima-Derived Fallout Particles

Energy Technology Data Exchange (ETDEWEB)

Martin, Peter George, E-mail: peter.martin@bristol.ac.uk [Interface Analysis Centre, School of Physics, University of Bristol, HH Wills Physics Laboratory, Bristol (United Kingdom); Satou, Yukihiko [Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency, Tomioka (Japan); Griffiths, Ian [Interface Analysis Centre, School of Physics, University of Bristol, HH Wills Physics Laboratory, Bristol (United Kingdom); Richards, David [School of Geographical Sciences, University of Bristol, Bristol (United Kingdom); Scott, Thomas [Interface Analysis Centre, School of Physics, University of Bristol, HH Wills Physics Laboratory, Bristol (United Kingdom)

2017-09-22

Three large high radioactivity particulate fragments, each several 100 μm in diameter, have been recovered from the region immediately surrounding the Fukushima Daiichi Nuclear Power Plant. Through the application of high-resolution electron and ion-beam methods, this work has sought to investigate the structure and composition of this fibrous surface morphology. By evaluating this, a potential material source can be determined, alongside important information relating to the conditions/events at the time of the reactor explosions and catastrophic release of radioactive materials. The results of this study show that the fibrous features associated with these large radiocesium-containing particles share a common elemental composition. With respect to the surrounding particle, the fibers are enriched in Si, Cl, and Fe, while depleted in both Zn and Al. Based on composition, these fibers are ascribed to thermal insulating material used within the plant, which was sufficiently heated during the loss of coolant incident at the plant to be incorporated into the molten ejecta material that rapidly solidified upon quenching in air. Elemental analysis of these fibers does not reveal any evidence of leaching or the presence of actinide materials.

Irregular activity arises as a natural consequence of synaptic inhibition

International Nuclear Information System (INIS)

Terman, D.; Rubin, J. E.; Diekman, C. O.

2013-01-01

Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects

Irregular activity arises as a natural consequence of synaptic inhibition

Energy Technology Data Exchange (ETDEWEB)

Terman, D., E-mail: terman@math.ohio-state.edu [Department of Mathematics, The Ohio State University, Columbus, Ohio 43210 (United States); Rubin, J. E., E-mail: jonrubin@pitt.edu [Department of Mathematics, University of Pittsburgh, Pittsburgh, Pennsylvania 15260 (United States); Diekman, C. O., E-mail: diekman@njit.edu [Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, New Jersey 07102 (United States)

2013-12-15

Irregular neuronal activity is observed in a variety of brain regions and states. This work illustrates a novel mechanism by which irregular activity naturally emerges in two-cell neuronal networks featuring coupling by synaptic inhibition. We introduce a one-dimensional map that captures the irregular activity occurring in our simulations of conductance-based differential equations and mathematically analyze the instability of fixed points corresponding to synchronous and antiphase spiking for this map. We find that the irregular solutions that arise exhibit expansion, contraction, and folding in phase space, as expected in chaotic dynamics. Our analysis shows that these features are produced from the interplay of synaptic inhibition with sodium, potassium, and leak currents in a conductance-based framework and provides precise conditions on parameters that ensure that irregular activity will occur. In particular, the temporal details of spiking dynamics must be present for a model to exhibit this irregularity mechanism and must be considered analytically to capture these effects.

Parallel Computing Strategies for Irregular Algorithms

Science.gov (United States)

Biswas, Rupak; Oliker, Leonid; Shan, Hongzhang; Biegel, Bryan (Technical Monitor)

2002-01-01

Parallel computing promises several orders of magnitude increase in our ability to solve realistic computationally-intensive problems, but relies on their efficient mapping and execution on large-scale multiprocessor architectures. Unfortunately, many important applications are irregular and dynamic in nature, making their effective parallel implementation a daunting task. Moreover, with the proliferation of parallel architectures and programming paradigms, the typical scientist is faced with a plethora of questions that must be answered in order to obtain an acceptable parallel implementation of the solution algorithm. In this paper, we consider three representative irregular applications: unstructured remeshing, sparse matrix computations, and N-body problems, and parallelize them using various popular programming paradigms on a wide spectrum of computer platforms ranging from state-of-the-art supercomputers to PC clusters. We present the underlying problems, the solution algorithms, and the parallel implementation strategies. Smart load-balancing, partitioning, and ordering techniques are used to enhance parallel performance. Overall results demonstrate the complexity of efficiently parallelizing irregular algorithms.

Advances in electron dosimetry of irregular fields; Avances en dosimetria de electrones de campos irregulares

Energy Technology Data Exchange (ETDEWEB)

Mendez V, J. [Departamento de Radioterapia, Instituto de Enfermedades Neoplasicas, Avenida Angamos Este 2520, Lima 34 (Peru)

1998-12-31

In this work it is presented an advance in Electron dosimetry of irregular fields for beams emitted by linear accelerators. At present diverse methods exist which are coming to apply in the Radiotherapy centers. In this work it is proposed a method for irregular fields dosimetry. It will be allow to calculate the dose rate absorbed required for evaluating the time for the treatment of cancer patients. Utilizing the results obtained by the dosimetric system, it has been possible to prove the validity of the method describe for 12 MeV energy and for square field 7.5 x 7.5 cm{sup 2} with percentile error less than 1 % . (Author)

Modeling pollutant transport using a meshless-lagrangian particle model

International Nuclear Information System (INIS)

Carrington, D.B.; Pepper, D.W.

2002-01-01

A combined meshless-Lagrangian particle transport model is used to predict pollutant transport over irregular terrain. The numerical model for initializing the velocity field is based on a meshless approach utilizing multiquadrics established by Kansa. The Lagrangian particle transport technique uses a random walk procedure to depict the advection and dispersion of pollutants over any type of surface, including street and city canyons

Role of parametric decay instabilities in generating ionospheric irregularities

International Nuclear Information System (INIS)

Kuo, S.P.; Cheo, B.R.; Lee, M.C.

1983-01-01

We show that purely growing instabilities driven by the saturation spectrum of parametric decay instabilities can produce a broad spectrum of ionospheric irregularities. The threshold field Vertical BarE/sub th/Vertical Bar of the instabilities decreases with the scale lengths lambda of the ionospheric irregularities as Vertical BarE/sub th/Vertical Barproportionallambda -2 in the small-scale range ( -2 with scale lengths larger than a few kilometers. The excitation of kilometer-scale irregularities is strictly restricted by the instabilities themselves and by the spatial inhomogeneity of the medium. These results are drawn from the analyses of four-wave interaction. Ion-neutral collisions impose no net effect on the instabilities when the excited ionospheric irregularities have a field-aligned nature

Particle shape accounts for instrumental discrepancy in ice core dust size distributions

Science.gov (United States)

Folden Simonsen, Marius; Cremonesi, Llorenç; Baccolo, Giovanni; Bosch, Samuel; Delmonte, Barbara; Erhardt, Tobias; Kjær, Helle Astrid; Potenza, Marco; Svensson, Anders; Vallelonga, Paul

2018-05-01

The Klotz Abakus laser sensor and the Coulter counter are both used for measuring the size distribution of insoluble mineral dust particles in ice cores. While the Coulter counter measures particle volume accurately, the equivalent Abakus instrument measurement deviates substantially from the Coulter counter. We show that the difference between the Abakus and the Coulter counter measurements is mainly caused by the irregular shape of dust particles in ice core samples. The irregular shape means that a new calibration routine based on standard spheres is necessary for obtaining fully comparable data. This new calibration routine gives an increased accuracy to Abakus measurements, which may improve future ice core record intercomparisons. We derived an analytical model for extracting the aspect ratio of dust particles from the difference between Abakus and Coulter counter data. For verification, we measured the aspect ratio of the same samples directly using a single-particle extinction and scattering instrument. The results demonstrate that the model is accurate enough to discern between samples of aspect ratio 0.3 and 0.4 using only the comparison of Abakus and Coulter counter data.

New Opportunities for Remote Sensing Ionospheric Irregularities by Fitting Scintillation Spectra

Science.gov (United States)

Carrano, C. S.; Rino, C. L.; Groves, K. M.

2017-12-01

In a recent paper, we presented a phase screen theory for the spectrum of intensity scintillations when the refractive index irregularities follow a two-component power law [Carrano and Rino, DOI: 10.1002/2015RS005903]. More recently we have investigated the inverse problem, whereby phase screen parameters are inferred from scintillation time series. This is accomplished by fitting the spectrum of intensity fluctuations with a parametrized theoretical model using Maximum Likelihood (ML) methods. The Markov-Chain Monte-Carlo technique provides a-posteriori errors and confidence intervals. The Akaike Information Criterion (AIC) provides justification for the use of one- or two-component irregularity models. We refer to this fitting as Irregularity Parameter Estimation (IPE) since it provides a statistical description of the irregularities from the scintillations they produce. In this talk, we explore some new opportunities for remote sensing ionospheric irregularities afforded by IPE. Statistical characterization of irregularities and the plasma bubbles in which they are embedded provides insight into the development of the underlying instability. In a companion paper by Rino et al., IPE is used to interpret scintillation due to simulated EPB structure. IPE can be used to reconcile multi-frequency scintillation observations and to construct high fidelity scintillation simulation tools. In space-to-ground propagation scenarios, for which an estimate of the distance to the scattering region is available a-priori, IPE enables retrieval of zonal irregularity drift. In radio occultation scenarios, the distance to the irregularities is generally unknown but IPE enables retrieval of Fresnel frequency. A geometric model for the effective scan velocity maps Fresnel frequency to Fresnel scale, yielding the distance to the irregularities. We demonstrate this approach by geolocating irregularities observed by the CORISS instrument onboard the C/NOFS satellite.

State reconstruction and irregular wavefunctions for the hydrogen atom

Science.gov (United States)

Krähmer, D. S.; Leonhardt, U.

1997-07-01

Inspired by a recently proposed procedure by Leonhardt and Raymer for wavepacket reconstruction, we calculate the irregular wavefunctions for the bound states of the Coulomb potential. We select the irregular solutions which have the simplest semiclassical limit.

On a new process for cusp irregularity production

Directory of Open Access Journals (Sweden)

H. C. Carlson

2008-09-01

Full Text Available Two plasma instability mechanisms were thought until 2007 to dominate the formation of plasma irregularities in the F region high latitude and polar ionosphere; the gradient-drift driven instability, and the velocity-shear driven instability. The former mechanism was accepted as accounting for plasma structuring in polar cap patches, the latter for plasma structuring in polar cap sun aligned arcs. Recent work has established the need to replace this view of the past two decades with a new patch plasma structuring process (not a new mechanism, whereby shear-driven instabilities first rapidly structure the entering plasma, after which gradient drift instabilities build on these large "seed" irregularities. Correct modeling of cusp and early polar cap patch structuring will not be accomplished without allowing for this compound process. This compound process explains several previously unexplained characteristics of cusp and early polar cap patch irregularities. Here we introduce additional data, coincident in time and space, to extend that work to smaller irregularity scale sizes and relate it to the structured cusp current system.

Ionospheric Irregularities at Mars Probed by MARSIS Topside Sounding

Science.gov (United States)

Harada, Y.; Gurnett, D. A.; Kopf, A. J.; Halekas, J. S.; Ruhunusiri, S.

2018-01-01

The upper ionosphere of Mars contains a variety of perturbations driven by solar wind forcing from above and upward propagating atmospheric waves from below. Here we explore the global distribution and variability of ionospheric irregularities around the exobase at Mars by analyzing topside sounding data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express. As irregular structure gives rise to off-vertical echoes with excess propagation time, the diffuseness of ionospheric echo traces can be used as a diagnostic tool for perturbed reflection surfaces. The observed properties of diffuse echoes above unmagnetized regions suggest that ionospheric irregularities with horizontal wavelengths of tens to hundreds of kilometers are particularly enhanced in the winter hemisphere and at high solar zenith angles. Given the known inverse dependence of neutral gravity wave amplitudes on the background atmospheric temperature, the ionospheric irregularities probed by MARSIS are most likely associated with plasma perturbations driven by atmospheric gravity waves. Though extreme events with unusually diffuse echoes are more frequently observed for high solar wind dynamic pressures during some time intervals, the vast majority of the diffuse echo events are unaffected by varying solar wind conditions, implying limited influence of solar wind forcing on the generation of ionospheric irregularities. Combination of remote and in situ measurements of ionospheric irregularities would offer the opportunity for a better understanding of the ionospheric dynamics at Mars.

Bottomside sinusoidal irregularities in the equatorial F region

Science.gov (United States)

Valladares, C. E.; Hanson, W. B.; Mcclure, J. P.; Cragin, B. L.

1983-01-01

By using the Ogo 6 satellite, McClure and Hanson (1973) have discovered sinusoidal irregularities in the equatorial F region ion number density. In the present investigation, a description is provided of the properties of a distinct category of sinusoidal irregularities found in equatorial data from the AE-C and AE-E satellites. The observed scale sizes vary from about 300 m to 3 km in the direction perpendicular to B, overlapping with and extending the range observed by using Ogo 6. Attention is given to low and high resolution data, a comparison with Huancayo ionograms, the confinement of 'bottomside sinusoidal' (BSS) irregularities essentially to the bottomside of the F layer, spectral characteristics, and BSS, scintillation, and ionosonde observations.

The Impact of Irregular Warfare on the US Army

National Research Council Canada - National Science Library

McDonald, III, Roger L

2006-01-01

Although the U.S. Army has yet to clearly define irregular warfare, it is imperative that the Army take near-term action to enhance the ability of Soldiers and units to operate effectively in an irregular warfare environment...

Influence of initial stress, irregularity and heterogeneity on Love-type wave propagation in double pre-stressed irregular layers lying over a pre-stressed half-space

Science.gov (United States)

Singh, Abhishek Kumar; Das, Amrita; Parween, Zeenat; Chattopadhyay, Amares

2015-10-01

The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half-space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface of uppermost initially stressed heterogeneous layer and intermediate initially stressed isotropic layer. Dispersion equations are obtained in closed form for both cases of irregularities, distinctly. The effect of size and shape of irregularity, horizontal compressive initial stress, horizontal tensile initial stress, heterogeneity of the uppermost layer and width ratio of the layers on phase velocity of Love-type wave are the major highlights of the study. Comparative study has been made to identify the effects of different shapes of irregularity, presence of heterogeneity and initial stresses. Numerical computations have been carried out and depicted by means of graphs for the present study.

On the Existence of Regular and Irregular Outer Moons Orbiting the Pluto–Charon System

Energy Technology Data Exchange (ETDEWEB)

Michaely, Erez; Perets, Hagai B.; Grishin, Evgeni [Physics Department, Technion—Israel Institute of Technology, Haifa 3200004 (Israel)

2017-02-10

The dwarf planet Pluto is known to host an extended system of five co-planar satellites. Previous studies have explored the formation and evolution of the system in isolation, neglecting perturbative effects by the Sun. Here we show that secular evolution due to the Sun can strongly affect the evolution of outer satellites and rings in the system, if such exist. Although precession due to extended gravitational potential from the inner Pluto–Charon binary quench such secular evolution up to a {sub crit} ∼ 0.0035 au (∼0.09 R {sub Hill} the Hill radius; including all of the currently known satellites), outer orbits can be significantly altered. In particular, we find that co-planar rings and satellites should not exist beyond a {sub crit}; rather, satellites and dust particles in these regions secularly evolve on timescales ranging between 10{sup 4} and 10{sup 6} years, and quasi-periodically change their inclinations and eccentricities through secular evolution (Lidov–Kozai oscillations). Such oscillations can lead to high inclinations and eccentricities, constraining the range where such satellites (and dust particles) can exist without crossing the orbits of the inner satellites or crossing the outer Hill stability range. Outer satellites, if such exist are therefore likely to be irregular satellites, with orbits limited to be non-circular and/or highly inclined. Current observations, including the recent data from the New-Horizons mission explored only inner regions (<0.0012 au) and excluded the existence of additional satellites; however, the irregular satellites discussed here should reside farther, in the yet uncharted regions around Pluto.

On the Existence of Regular and Irregular Outer Moons Orbiting the Pluto–Charon System

International Nuclear Information System (INIS)

Michaely, Erez; Perets, Hagai B.; Grishin, Evgeni

2017-01-01

The dwarf planet Pluto is known to host an extended system of five co-planar satellites. Previous studies have explored the formation and evolution of the system in isolation, neglecting perturbative effects by the Sun. Here we show that secular evolution due to the Sun can strongly affect the evolution of outer satellites and rings in the system, if such exist. Although precession due to extended gravitational potential from the inner Pluto–Charon binary quench such secular evolution up to a crit ∼ 0.0035 au (∼0.09 R Hill the Hill radius; including all of the currently known satellites), outer orbits can be significantly altered. In particular, we find that co-planar rings and satellites should not exist beyond a crit ; rather, satellites and dust particles in these regions secularly evolve on timescales ranging between 10 4 and 10 6 years, and quasi-periodically change their inclinations and eccentricities through secular evolution (Lidov–Kozai oscillations). Such oscillations can lead to high inclinations and eccentricities, constraining the range where such satellites (and dust particles) can exist without crossing the orbits of the inner satellites or crossing the outer Hill stability range. Outer satellites, if such exist are therefore likely to be irregular satellites, with orbits limited to be non-circular and/or highly inclined. Current observations, including the recent data from the New-Horizons mission explored only inner regions (<0.0012 au) and excluded the existence of additional satellites; however, the irregular satellites discussed here should reside farther, in the yet uncharted regions around Pluto.

Laser pushing or pulling of absorbing airborne particles

Energy Technology Data Exchange (ETDEWEB)

Wang, Chuji, E-mail: cw175@msstate.edu; Gong, Zhiyong [Mississippi State University, Starkville, Mississippi 39759 (United States); Pan, Yong-Le; Videen, Gorden [U.S. Army Research Laboratory, 2800 Powder Mill Road, Adelphi, Maryland 20783 (United States)

2016-07-04

A single absorbing particle formed by carbon nanotubes in the size range of 10–50 μm is trapped in air by a laser trapping beam and concurrently illuminated by another laser manipulating beam. When the trapping beam is terminated, the movement of the particle controlled by the manipulating beam is investigated. We report our observations of light-controlled pushing and pulling motions. We show that the movement direction has little relationship with the particle size and manipulating beam's parameters but is dominated by the particle's orientation and morphology. With this observation, the controllable optical manipulation is now able to be generalized to arbitrary particles, including irregularly shaped absorbing particles that are shown in this work.

Wavelet analysis of angular spectra of relativistic particles in 208Pb induced collisions with emulsion nuclei at 158A GeV/c

International Nuclear Information System (INIS)

Fedorisin, J.; Vokal, S.

2008-01-01

The continuous wavelet transform is applied to the pseudorapidity spectra of relativistic secondary particles created in Pb + Em nuclear collisions at 158A GeV/c. The wavelet pseudorapidity spectra are subsequently surveyed at different scales to look for signs of ring-like correlations whose presence could be explained either via the production of Cherenkov gluons or the propagation of Mach shock waves in excited nuclear medium. The presented approach is established on the basic prerequisite that the both effects would lead to excess of particles at certain typical pseudorapidities. Furthermore, the particles contributing to the ring-like structures are expected to have uniform azimuthal distributions. The multiscale analysis of the wavelet pseudorapidity spectra reveals the irregularities which are interpreted as the favoured pseudorapidities of groups of produced particles. A uniformity of the azimuthal structure of the disclosed pseudorapidity irregularities is examined, eventually leading to the conclusion that the irregularities are not related to correlations of a ring-like nature

Software support for irregular and loosely synchronous problems

Science.gov (United States)

Choudhary, A.; Fox, G.; Hiranandani, S.; Kennedy, K.; Koelbel, C.; Ranka, S.; Saltz, J.

1992-01-01

A large class of scientific and engineering applications may be classified as irregular and loosely synchronous from the perspective of parallel processing. We present a partial classification of such problems. This classification has motivated us to enhance FORTRAN D to provide language support for irregular, loosely synchronous problems. We present techniques for parallelization of such problems in the context of FORTRAN D.

Irregular Shaped Building Design Optimization with Building Information Modelling

Directory of Open Access Journals (Sweden)

Lee Xia Sheng

2016-01-01

Full Text Available This research is to recognise the function of Building Information Modelling (BIM in design optimization for irregular shaped buildings. The study focuses on a conceptual irregular shaped “twisted” building design similar to some existing sculpture-like architectures. Form and function are the two most important aspects of new buildings, which are becoming more sophisticated as parts of equally sophisticated “systems” that we are living in. Nowadays, it is common to have irregular shaped or sculpture-like buildings which are very different when compared to regular buildings. Construction industry stakeholders are facing stiff challenges in many aspects such as buildability, cost effectiveness, delivery time and facility management when dealing with irregular shaped building projects. Building Information Modelling (BIM is being utilized to enable architects, engineers and constructors to gain improved visualization for irregular shaped buildings; this has a purpose of identifying critical issues before initiating physical construction work. In this study, three variations of design options differing in rotating angle: 30 degrees, 60 degrees and 90 degrees are created to conduct quantifiable comparisons. Discussions are focused on three major aspects including structural planning, usable building space, and structural constructability. This research concludes that Building Information Modelling is instrumental in facilitating design optimization for irregular shaped building. In the process of comparing different design variations, instead of just giving “yes or no” type of response, stakeholders can now easily visualize, evaluate and decide to achieve the right balance based on their own criteria. Therefore, construction project stakeholders are empowered with superior evaluation and decision making capability.

Saturn's Irregular Moon Ymir

Science.gov (United States)

Denk, Tilmann; Mottola, S.

2012-10-01

Ymir (diameter 18 km), Saturn's second largest retrograde outer or irregular moon, has been observed six times by the Cassini narrow-angle camera (NAC) during the first 7 months in 2012. The observations span phase angles from 2° up to 102° and were taken at ranges between 15 and 18 million kilometers. From such a distance, Ymir is smaller than a pixel in the Cassini NAC. The data reveal a sidereal rotation period of 11.93 hrs, which is 1.6x longer than the previously reported value (Denk et al. 2011, EPSC/DPS #1452). Reason for this discrepancy is that the rotational light curve shows a rather uncommon 3-maxima and 3-minima shape at least in the phase angle range 50° to 100°, which was not recognizable in earlier data. The data cover several rotations from different viewing and illumination geometries and allow for a convex shape inversion with possibly a unique solution for the pole direction. The model reproduces the observed light curves to a very good accuracy without requiring albedo variegation, thereby suggesting that the lightcurve is dominated by the shape of Ymir. Among Saturn's irregular moons, the phenomenon of more than two maxima and minima at moderate to high phase angles is not unique to Ymir. At least Siarnaq and Paaliaq also show light curves with a strong deviation from a double-sine curve. Their rotation periods, however, remain unknown until more data can be taken. The light curve of Phoebe is fundamentally different to Ymir's because it is mainly shaped by local albedo differences and not by shape. Other reliable rotation periods of irregular satellites measured by Cassini include: Mundilfari 6.74 h; Kari 7.70 h; Albiorix 13.32 h; Kiviuq 21.82 h. More uncertain values are: Skathi 12 h; Bebhionn 16 h; Thrymr 27 h; Erriapus 28 h.

Uniform irradiation of irregularly shaped cavities for photodynamic therapy

NARCIS (Netherlands)

Rem, A. I.; van Gemert, M. J.; van der Meulen, F. W.; Gijsbers, G. H.; Beek, J. F.

1997-01-01

It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a

Q-space analysis of scattering by particles: A review

International Nuclear Information System (INIS)

Sorensen, Christopher M.

2013-01-01

This review describes and demonstrates the Q-space analysis of light scattering by particles. This analysis involves plotting the scattered intensity versus the scattering wave vector q=(4π/λ)sin(θ/2) on a double log plot. The analysis uncovers power law descriptions of the scattering with length scale dependent crossovers between the power laws. It also systematically describes the magnitude of the scattering and the interference ripple structure that often underlies the power laws. It applies to scattering from dielectric spheres of arbitrary size and refractive index (Mie scattering), fractal aggregates and irregularly shaped particles such as dusts. The benefits of Q-space analysis are that it provides a simple and comprehensive description of scattering in terms of power laws with quantifiable exponents; it can be used to differentiate scattering by particles of different shapes, and it yields a physical understanding of scattering based on diffraction. -- Highlights: ► Angular scattering functions for spheres show power laws versus the wave vector q. ► The power laws uncover patterns involving length scales and functionalities. ► Similar power laws appear in scattering from aggregates and irregular particles. ► Power laws provide a comprehensive and quantitative description of scattering

Fundamental study of single biomass particle combustion

Energy Technology Data Exchange (ETDEWEB)

Momeni, M.

2013-06-01

This thesis is a comprehensive study of single biomass particle combustion. The effect of particle shape and size and operating conditions on biomass conversion characteristics were investigated experimentally and theoretically. The experimental samples were divided in two groups: particles with regular shapes (spheres and cylinders) and particles with irregular shapes (almost flake-like). A CAMSIZER analyser (Retsch Technology GMBH) was used to determine the size and shape of the particles via Dynamical Digital Image Processing. The experiments were performed in a single particle reactor under well-defined conditions, and the complete combustion processes were recorded as video sequences by a CCD camera installed in the set-up. One of the project objectives is to simulate conditions reasonably close to the conditions in a power plant boiler, i.e., reasonably high temperatures (up to 1600 deg. C) and varying oxygen concentrations in the 5 to 20% range. A one-dimensional mathematical model was used to simulate all the intraparticle conversion processes (drying, recondensation, devolatilisation, char gasification/oxidation and heat/mass/momentum transfer) within single particles of different shapes and size under various conditions. The model also predicts the flame layer domain of a single particle. The model was validated by experimental results under different conditions; good agreement between the model predictions and the experimental data was observed. Both the experimental and modelling results showed that cylindrical particles lose mass faster than spherical particles of a similar volume (mass) and that the burnout time is reduced by increasing the particle aspect ratio (surface area to volume ratio). Very similar conversion times were observed for cylindrical particles with nearly identical surface area to volume ratios. Similar conversion times were also observed for two size classes of pulverised particles (with irregular shapes) made from the same type of

Analysis of an Irregular RC Multi-storeyed Building Subjected to Dynamic Loading

Science.gov (United States)

AkashRaut; Pachpor, Prabodh; Dautkhani, Sanket

2018-03-01

Many buildings in the present scenario have irregular configurations both in plan and elevation. This in future may subject to devastating earthquakes. So it is necessary to analyze the structure. The present paper is made to study three type of irregularity wiz vertical, mass and plan irregularity as per clause 7.1 of IS 1893 (part1)2002 code. The paper discusses the analysis of RC (Reinforced Concrete) Buildings with vertical irregularity. The study as a whole makes an effort to evaluate the effect of vertical irregularity on RC buildings for which comparison of three parameters namely shear force, bending moment and deflection are taken into account.

Spatial irregularities in Jupiter's upper ionosphere observed by Voyager radio occultations

Science.gov (United States)

Hinson, D. P.; Tyler, G. L.

1982-01-01

Radio scintillations (at 3.6 and 13 cm) produced by scattering from ionospheric irregularities during the Voyager occultations are interpreted using a weak-scattering theory. Least squares solutions for ionospheric parameters derived from the observed fluctuation spectra yield estimates of (1) the axial ratio, (2) angular orientation of the anisotropic irregularities, (3) the power law exponent of the spatial spectrum of irregularities, and (4) the magnitude of the spatial variations in electron density. It is shown that the measured angular orientation of the anisotropic irregularities indicates magnetic field direction and may provide a basis for refining Jovian magnetic field models.

Irregular Dwarf Galaxy IC 1613

Science.gov (United States)

2005-01-01

Ultraviolet image (left) and visual image (right) of the irregular dwarf galaxy IC 1613. Low surface brightness galaxies, such as IC 1613, are more easily detected in the ultraviolet because of the low background levels compared to visual wavelengths.

Regularisation of irregular verbs in child English second language ...

African Journals Online (AJOL)

Data was collected from the language of English medium preschool children. The study concludes that when the Blocking Principle interferes, children resort to a novel interlanguage rule that regularises irregular verbs. This interlanguage rule applies in a similar way to all irregular verbs, thus children produce utterances ...

Low frequency sound reproduction in irregular rooms using CABS (Control Acoustic Bass System)

DEFF Research Database (Denmark)

Celestinos, Adrian; Nielsen, Sofus Birkedal

2011-01-01

of an irregular room model using the FDTD (Finite Difference Time Domain) method has been presented. CABS has been simulated in the irregular room model. Measurements of CABS in a real irregular room have been performed. The performance of CABS was affected by the irregular shape of the room due to the corner...

Total edge irregularity strength of (n,t)-kite graph

Science.gov (United States)

Winarsih, Tri; Indriati, Diari

2018-04-01

Let G(V, E) be a simple, connected, and undirected graph with vertex set V and edge set E. A total k-labeling is a map that carries vertices and edges of a graph G into a set of positive integer labels {1, 2, …, k}. An edge irregular total k-labeling λ :V(G)\\cup E(G)\\to \\{1,2,\\ldots,k\\} of a graph G is a labeling of vertices and edges of G in such a way that for any different edges e and f, weights wt(e) and wt(f) are distinct. The weight wt(e) of an edge e = xy is the sum of the labels of vertices x and y and the label of the edge e. The total edge irregularity strength of G, tes(G), is defined as the minimum k for which a graph G has an edge irregular total k-labeling. An (n, t)-kite graph consist of a cycle of length n with a t-edge path (the tail) attached to one vertex of a cycle. In this paper, we investigate the total edge irregularity strength of the (n, t)-kite graph, with n > 3 and t > 1. We obtain the total edge irregularity strength of the (n, t)-kite graph is tes((n, t)-kite) = \\lceil \\frac{n+t+2}{3}\\rceil .

SiO2-supported Pt particles studied by electron microscopy

International Nuclear Information System (INIS)

Wang, D.; Penner, S.; Su, D.S.; Rupprechter, G.; Hayek, K.; Schloegl, R.

2003-01-01

Regularly grown Pt particles supported by amorphous SiO 2 were heated in hydrogen at 873 K after an oxidising treatment. The morphological and structural changes were studied by electron microscopy. Platinum silicides Pt 3 Si with L1 2 (Cu 3 Au) structure, monoclinic Pt 3 Si and tetragonal Pt 12 Si 5 were identified after the treatment. The mechanisms of coalescence of the particles and the formation of irregular large particles are suggested. A topotactic structural transformation accompanied with the migration of Si from the substrate to the particles are suggested to take place during Pt 3 Si formation

Classical limit of irregular blocks and Mathieu functions

International Nuclear Information System (INIS)

Piątek, Marcin; Pietrykowski, Artur R.

2016-01-01

The Nekrasov-Shatashvili limit of the N = 2 SU(2) pure gauge (Ω-deformed) super Yang-Mills theory encodes the information about the spectrum of the Mathieu operator. On the other hand, the Mathieu equation emerges entirely within the frame of two-dimensional conformal field theory (2d CFT) as the classical limit of the null vector decoupling equation for some degenerate irregular block. Therefore, it seems to be possible to investigate the spectrum of the Mathieu operator employing the techniques of 2d CFT. To exploit this strategy, a full correspondence between the Mathieu equation and its realization within 2d CFT has to be established. In our previous paper http://dx.doi.org/10.1007/JHEP12(2014)032, we have found that the expression of the Mathieu eigenvalue given in terms of the classical irregular block exactly coincides with the well known weak coupling expansion of this eigenvalue in the case in which the auxiliary parameter is the noninteger Floquet exponent. In the present work we verify that the formula for the corresponding eigenfunction obtained from the irregular block reproduces the so-called Mathieu exponent from which the noninteger order elliptic cosine and sine functions may be constructed. The derivation of the Mathieu equation within the formalism of 2d CFT is based on conjectures concerning the asymptotic behaviour of irregular blocks in the classical limit. A proof of these hypotheses is sketched. Finally, we speculate on how it could be possible to use the methods of 2d CFT in order to get from the irregular block the eigenvalues of the Mathieu operator in other regions of the coupling constant.

Track Irregularity Time Series Analysis and Trend Forecasting

Directory of Open Access Journals (Sweden)

Jia Chaolong

2012-01-01

Full Text Available The combination of linear and nonlinear methods is widely used in the prediction of time series data. This paper analyzes track irregularity time series data by using gray incidence degree models and methods of data transformation, trying to find the connotative relationship between the time series data. In this paper, GM (1,1 is based on first-order, single variable linear differential equations; after an adaptive improvement and error correction, it is used to predict the long-term changing trend of track irregularity at a fixed measuring point; the stochastic linear AR, Kalman filtering model, and artificial neural network model are applied to predict the short-term changing trend of track irregularity at unit section. Both long-term and short-term changes prove that the model is effective and can achieve the expected accuracy.

Examining U.S. Irregular Warfare Doctrine

National Research Council Canada - National Science Library

Kimbrough, IV, James M

2008-01-01

... of insurgency and terrorism. In response to the associated strategic challenges, a growing debate occurred among military historians, strategists, and leaders about the proper principles necessary for contemporary irregular...

Traffic dispersion through a series of signals with irregular split

Science.gov (United States)

Nagatani, Takashi

2016-01-01

We study the traffic behavior of a group of vehicles moving through a sequence of signals with irregular splits on a roadway. We present the stochastic model of vehicular traffic controlled by signals. The dynamic behavior of vehicular traffic is clarified by analyzing traffic pattern and travel time numerically. The group of vehicles breaks up more and more by the irregularity of signal's split. The traffic dispersion is induced by the irregular split. We show that the traffic dispersion depends highly on the cycle time and the strength of split's irregularity. Also, we study the traffic behavior through the series of signals at the green-wave strategy. The dependence of the travel time on offset time is derived for various values of cycle time. The region map of the traffic dispersion is shown in (cycle time, offset time)-space.

GARCH and Irregularly Spaced Data

NARCIS (Netherlands)

Meddahi, N.; Renault, E.; Werker, B.J.M.

2003-01-01

An exact discretization of continuous time stochastic volatility processes observed at irregularly spaced times is used to give insights on how a coherent GARCH model can be specified for such data. The relation of our approach with those in the existing literature is studied.

Crime among irregular immigrants and the influence of internal border control

OpenAIRE

Leerkes, Arjen; Engbersen, Godfried; Leun, Joanne

2012-01-01

textabstractBoth the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular immigrants from the formal labour market and public provisions. At the same time the registered crime among irregular migrants rose. The 'marginalisation thesis' asserts that a larger number of migrants hav...

Stereotactic radiosurgery. The role of charged particles

Energy Technology Data Exchange (ETDEWEB)

Levy, R.P.; Schulte, R.W.M.; Slater, J.D.; Miller, D.W.; Slater, J.M. [Loma Linda Univ. Medical Center, CA (United States). Dept. of Radiation Medicine

1999-08-01

Stereotactic radiosurgery using charged-particle beams has been the subject of biomedical research and clinical development for more than 50 years. Charged particles of proton mass or greater manifest unique physical properties that can be used to place a high dose of radiation preferentially within the boundaries of a deeply located intracranial target volume. Since 1954, nearly 10 000 patients have been treated using this technique. Treated disorders include pituitary tumors, vascular malformations, primary and metastatic brain tumors, and subfoveal neovascularization. Charged-particle radiosurgery is particularly advantageous for the conformal treatment of large and/or irregularly shaped lesions, or for the treatment of lesions located in front of or adjacent to sensitive brain structures. (orig.)

Stereotactic radiosurgery. The role of charged particles

International Nuclear Information System (INIS)

Levy, R.P.; Schulte, R.W.M.; Slater, J.D.; Miller, D.W.; Slater, J.M.

1999-01-01

Stereotactic radiosurgery using charged-particle beams has been the subject of biomedical research and clinical development for more than 50 years. Charged particles of proton mass or greater manifest unique physical properties that can be used to place a high dose of radiation preferentially within the boundaries of a deeply located intracranial target volume. Since 1954, nearly 10 000 patients have been treated using this technique. Treated disorders include pituitary tumors, vascular malformations, primary and metastatic brain tumors, and subfoveal neovascularization. Charged-particle radiosurgery is particularly advantageous for the conformal treatment of large and/or irregularly shaped lesions, or for the treatment of lesions located in front of or adjacent to sensitive brain structures. (orig.)

Measurements of electron density irregularities in the ionosphere of Jupiter by Pioneer 10

International Nuclear Information System (INIS)

Woo, R.; Yang, F.

1976-01-01

In this paper we demonstrate that when the frequency spectrum of the log amplitude fluctuations is used, the radio occultation experiment is a powerful tool for detecting, identifying, and studying ionospheric irregularities. Analysis of the Pioneer 10 radio occultation measurements reveals that the Jovian ionosphere possesses electron density irregularities which are very similar to those found in the earth's ionosphere. This is the first time such irregularities have been found in a planetary ionosphere other than that of earth. The Pioneer 10 results indicate that the spatial wave number spectrum of the electron density irregularities is close to the Kolmogorov spectrum and that the outer scale size is greater than the Fresnel size (6.15 km). This type of spectrum suggests that the irregularities are probably produced by the turbulent dissipation of irregularities larger than the outer scale size

Coolability of volumetrically heated particle beds

Energy Technology Data Exchange (ETDEWEB)

Rashid, Muhammad

2017-03-22

In case of a severe nuclear reactor accident, with loss of coolant, a particle bed may be formed from the fragmentation of the molten core in the residual water at different stages of the accident. To avoid further propagation of the accident and maintain the integrity of the reactor pressure vessel, the decay heat of the particle bed must be removed. To better understand the various thermo-hydraulic processes within such heat-generating particle beds, the existing DEBRIS test facility at IKE has been modified to be able to perform novel boiling, dryout and quenching experiments. The essential experimental data includes the pressure gradients measured by 8 differential pressure transducers along the bed height as a function of liquid and vapour superficial velocities, the determination of local dryout heat fluxes for different system pressures as well as the local temperature distribution measured by a set of 51 thermocouples installed inside the particle bed. The experiments were carried out for two different particle beds: a polydispersed particle bed which consisted of stainless steel balls (2 mm, 3 mm and 6 mm diameters) and an irregular particle bed which consisted of a mixture of steel balls (3 mm and 6 mm) and irregularly shaped Al{sub 2}O{sub 3} particles. Additionally, all experiments were carried out for different flow conditions, such as the reference case of passive 1D top-flooding, 1D bottom flooding (driven by external pumps and different downcomer configurations) and 2D top-/bottom-/lateral flooding with a perforated downcomer. In this work, it has been observed that for both particle beds with downcomer configurations an open downcomer leads to the best coolability (dryout heat flux = 1560 kW/m{sup 2}, polydispersed particle bed, psys = 1 bar) of the particle bed, mainly due to bottom-flow with enhanced natural convection. It has also been shown that a potential lateral flow via a perforation of the downcomer does not bring any further improvements

Coolability of volumetrically heated particle beds

International Nuclear Information System (INIS)

Rashid, Muhammad

2017-01-01

In case of a severe nuclear reactor accident, with loss of coolant, a particle bed may be formed from the fragmentation of the molten core in the residual water at different stages of the accident. To avoid further propagation of the accident and maintain the integrity of the reactor pressure vessel, the decay heat of the particle bed must be removed. To better understand the various thermo-hydraulic processes within such heat-generating particle beds, the existing DEBRIS test facility at IKE has been modified to be able to perform novel boiling, dryout and quenching experiments. The essential experimental data includes the pressure gradients measured by 8 differential pressure transducers along the bed height as a function of liquid and vapour superficial velocities, the determination of local dryout heat fluxes for different system pressures as well as the local temperature distribution measured by a set of 51 thermocouples installed inside the particle bed. The experiments were carried out for two different particle beds: a polydispersed particle bed which consisted of stainless steel balls (2 mm, 3 mm and 6 mm diameters) and an irregular particle bed which consisted of a mixture of steel balls (3 mm and 6 mm) and irregularly shaped Al 2 O 3 particles. Additionally, all experiments were carried out for different flow conditions, such as the reference case of passive 1D top-flooding, 1D bottom flooding (driven by external pumps and different downcomer configurations) and 2D top-/bottom-/lateral flooding with a perforated downcomer. In this work, it has been observed that for both particle beds with downcomer configurations an open downcomer leads to the best coolability (dryout heat flux = 1560 kW/m 2 , polydispersed particle bed, psys = 1 bar) of the particle bed, mainly due to bottom-flow with enhanced natural convection. It has also been shown that a potential lateral flow via a perforation of the downcomer does not bring any further improvements in

Influence of initial stress, irregularity and heterogeneity on Love-type ...

Indian Academy of Sciences (India)

The present paper deals with the propagation of Love-type wave in an initially stressed irregular vertically heterogeneous layer lying over an initially stressed isotropic layer and an initially stressed isotropic half- space. Two different types of irregularities, viz., rectangular and parabolic, are considered at the interface.

Effect of particle shapes on effective strain gradient of SiC particle reinforced aluminum composites

International Nuclear Information System (INIS)

Liu, X; Cao, D F; Mei, H; Liu, L S; Lei, Z T

2013-01-01

The stress increments depend not only on the plastic strain but also on the gradient of plastic strain, when the characteristic length scale associated with non-uniform plastic deformation is on the order of microns. In the present research, the Taylor-based nonlocal theory of plasticity (TNT plasticity), with considering both geometrically necessary dislocations and statistically stored dislocations, is applied to investigated the effect of particle shapes on the strain gradient and mechanical properties of SiC particle reinforced aluminum composites (SiC/Al composites). Based on this theory, a two-dimensional axial symmetry cell model is built in the ABAQUS finite element code through its USER-ELEMENT (UEL) interface. Some comparisons with the classical plastic theory demonstrate that the effective stress predicted by TNT plasticity is obviously higher than that predicted by classical plastic theory. The results also demonstrate that the irregular particles cause higher effective gradient strain which is attributed to the fact that angular shape particles give more geometrically.

Characterizing neural activities evoked by manual acupuncture through spiking irregularity measures

International Nuclear Information System (INIS)

Xue Ming; Wang Jiang; Deng Bin; Wei Xi-Le; Yu Hai-Tao; Chen Ying-Yuan

2013-01-01

The neural system characterizes information in external stimulations by different spiking patterns. In order to examine how neural spiking patterns are related to acupuncture manipulations, experiments are designed in such a way that different types of manual acupuncture (MA) manipulations are taken at the ‘Zusanli’ point of experimental rats, and the induced electrical signals in the spinal dorsal root ganglion are detected and recorded. The interspike interval (ISI) statistical histogram is fitted by the gamma distribution, which has two parameters: one is the time-dependent firing rate and the other is a shape parameter characterizing the spiking irregularities. The shape parameter is the measure of spiking irregularities and can be used to identify the type of MA manipulations. The coefficient of variation is mostly used to measure the spike time irregularity, but it overestimates the irregularity in the case of pronounced firing rate changes. However, experiments show that each acupuncture manipulation will lead to changes in the firing rate. So we combine four relatively rate-independent measures to study the irregularity of spike trains evoked by different types of MA manipulations. Results suggest that the MA manipulations possess unique spiking statistics and characteristics and can be distinguished according to the spiking irregularity measures. These studies have offered new insights into the coding processes and information transfer of acupuncture. (interdisciplinary physics and related areas of science and technology)

Advances in electron dosimetry of irregular fields

International Nuclear Information System (INIS)

Mendez V, J.

1998-01-01

In this work it is presented an advance in Electron dosimetry of irregular fields for beams emitted by linear accelerators. At present diverse methods exist which are coming to apply in the Radiotherapy centers. In this work it is proposed a method for irregular fields dosimetry. It will be allow to calculate the dose rate absorbed required for evaluating the time for the treatment of cancer patients. Utilizing the results obtained by the dosimetric system, it has been possible to prove the validity of the method describe for 12 MeV energy and for square field 7.5 x 7.5 cm 2 with percentile error less than 1 % . (Author)

New Model for Ionospheric Irregularities at Mars

Science.gov (United States)

Keskinen, M. J.

2018-03-01

A new model for ionospheric irregularities at Mars is presented. It is shown that wind-driven currents in the dynamo region of the Martian ionosphere can be unstable to the electromagnetic gradient drift instability. This plasma instability can generate ionospheric density and magnetic field irregularities with scale sizes of approximately 15-20 km down to a few kilometers. We show that the instability-driven magnetic field fluctuation amplitudes relative to background are correlated with the ionospheric density fluctuation amplitudes relative to background. Our results can explain recent observations made by the Mars Atmosphere and Volatile EvolutioN spacecraft in the Martian ionosphere dynamo region.

Edge irregular total labellings for graphs of linear size

DEFF Research Database (Denmark)

Brandt, Stephan; Rautenbach, D.; Miškuf, J.

2009-01-01

As an edge variant of the well-known irregularity strength of a graph G = (V, E) we investigate edge irregular total labellings, i.e. functions f : V ∪ E → {1, 2, ..., k} such that f (u) + f (u v) + f (v) ≠ f (u) + f (u v) + f (v) for every pair of different edges u v, u v ∈ E. The smallest possi...

Study of Track Irregularity Time Series Calibration and Variation Pattern at Unit Section

Directory of Open Access Journals (Sweden)

Chaolong Jia

2014-01-01

Full Text Available Focusing on problems existing in track irregularity time series data quality, this paper first presents abnormal data identification, data offset correction algorithm, local outlier data identification, and noise cancellation algorithms. And then proposes track irregularity time series decomposition and reconstruction through the wavelet decomposition and reconstruction approach. Finally, the patterns and features of track irregularity standard deviation data sequence in unit sections are studied, and the changing trend of track irregularity time series is discovered and described.

Oxidation of nickel particles in an environmental TEM

DEFF Research Database (Denmark)

Jeangros, Q.; Hansen, Thomas Willum; Wagner, Jakob Birkedal

nanometres in size. These domains impinge and cover the particles surface. As the temperature increases under O2, the NiO film grows and creates irregular structures composed of many crystallites. The reaction kinetics are inferred by EELS using different techniques analyzing changes in shapes of the Ni L2...... temperature, providing new insights into oxidation/corrosion processes....

Dispersion of silver particles in aqueous solutions visualized by polarography/voltammetry

Energy Technology Data Exchange (ETDEWEB)

Korshunov, Andrey [Department of General and Inorganic Chemistry, Tomsk Polytechnic University, 634050 Tomsk (Russian Federation); Heyrovsky, Michael [J.Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, Dolejskova 3, 182 23 Prague (Czech Republic)], E-mail: heyrovsk@jh-inst.cas.cz

2009-11-01

The State of silver particles in aqueous dispersions and the course of their coagulation can be followed on voltammetric curves recorded with hanging mercury drop electrode. Sharp irregular cathodic current peaks produced by partial electroreduction of the species adsorbed on the surface of silver particles during their fortuitous impingements upon the electrode surface appear in time sequence on the curves. A change in the electrochemical behavior of silver sols in the time course of particles aggregation and growth was interpreted in agreement with the data of UV-vis spectroscopy and electron microscopy observations.

Characterizing spontaneous irregular behavior in coupled map lattices

International Nuclear Information System (INIS)

Dobyns, York; Atmanspacher, Harald

2005-01-01

Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties

Characterizing spontaneous irregular behavior in coupled map lattices

Energy Technology Data Exchange (ETDEWEB)

Dobyns, York [PEAR, Princeton University Princeton, NJ 08544-5263 (United States); Atmanspacher, Harald [Institut fuer Grenzgebiete der Psychologie und Psychohygiene Wilhelmstrasse 3a, Freiburg 79098 (Germany)]. E-mail: haa@igpp.de

2005-04-01

Two-dimensional coupled map lattices display, in a specific parameter range, a stable phase (quasi-) periodic in both space and time. With small changes to the model parameters, this stable phase develops spontaneous eruptions of non-periodic behavior. Although this behavior itself appears irregular, it can be characterized in a systematic fashion. In particular, parameter-independent features of the spontaneous eruptions may allow useful empirical characterizations of other phenomena that are intrinsically hard to predict and reproduce. Specific features of the distributions of lifetimes and emergence rates of irregular states display such parameter-independent properties.

Dose calculations for irregular fields using three-dimensional first-scatter integration

International Nuclear Information System (INIS)

Boesecke, R.; Scharfenberg, H.; Schlegel, W.; Hartmann, G.H.

1986-01-01

This paper describes a method of dose calculations for irregular fields which requires only the mean energy of the incident photons, the geometrical properties of the irregular field and of the therapy unit, and the attenuation coefficient of tissue. The method goes back to an approach including spatial aspects of photon scattering for inhomogeneities for the calculation of dose reduction factors as proposed by Sontag and Cunningham (1978). It is based on the separation of dose into a primary component and a scattered component. The scattered component can generally be calculated for each field by integration over dose contributions from scattering in neighbouring volume elements. The quotient of this scattering contribution in the irregular field and the scattering contribution in the equivalent open field is then the correction factor for scattering in an irregular field. A correction factor for the primary component can be calculated if the attenuation of the photons in the shielding block is properly taken into account. The correction factor is simply given by the quotient of primary photons of the irregular field and the primary photons of the open field. (author)

Using forbidden ordinal patterns to detect determinism in irregularly sampled time series.

Science.gov (United States)

Kulp, C W; Chobot, J M; Niskala, B J; Needhammer, C J

2016-02-01

It is known that when symbolizing a time series into ordinal patterns using the Bandt-Pompe (BP) methodology, there will be ordinal patterns called forbidden patterns that do not occur in a deterministic series. The existence of forbidden patterns can be used to identify deterministic dynamics. In this paper, the ability to use forbidden patterns to detect determinism in irregularly sampled time series is tested on data generated from a continuous model system. The study is done in three parts. First, the effects of sampling time on the number of forbidden patterns are studied on regularly sampled time series. The next two parts focus on two types of irregular-sampling, missing data and timing jitter. It is shown that forbidden patterns can be used to detect determinism in irregularly sampled time series for low degrees of sampling irregularity (as defined in the paper). In addition, comments are made about the appropriateness of using the BP methodology to symbolize irregularly sampled time series.

Scintillations associated with bottomside sinusoidal irregularities in the equatorial F region

Science.gov (United States)

Basu, S.; Basu, S.; Valladares, C. E.; Dasgupta, A.; Whitney, H. E.

1986-01-01

Multisatellite scintillation observations and spaced receiver drift measurements are presented for a category of equatorial F region plasma irregularities characterized by nearly sinusoidal waveforms in the ion number density. The observations were made at Huancayo, Peru, and the measurements at Ancon, Peru, associated with irregularities observed by the Atmospheric-Explorer-E satellite on a few nights in December 1979. Utilizing ray paths to various geostationary satellites, it was found that the irregularities grow and decay almost simultaneously in long-lived patches extending at least 1000 km in the east-west direction.

The structure of plasma-density irregularities in the interplanetary medium

International Nuclear Information System (INIS)

Singleton, D.G.

1975-01-01

The conflict in the literature as to whether the plasma-density spatial spectrum of the irregularities in the interplanetary medium is of Gaussian or power law form is discussed. Particular attention is paid to the interplanetary scintillation effects ascribed to these irregularities. It is shown that the phase-screen theory of scintillations can be invoked to devise a set of critical tests which provide a means of discriminating between the conflicting hypotheses. Differences in the predicted behaviour of the single sensor temporal spectra of the scintillations for the two irregularity forms provide the main tests of the conflicting hypotheses. However, it is also shown that the two hypotheses lead to different forms of the variation of scintillation index with the observing frequency and the solar elongation of the scintillating source. Consideration is given to the optimum conditions for observing the Fourier and Bessel temporal spectra modulation which is due to the Fresnel filtering of the spatial spectrum. Determination of irregularity shape, orientation and motion in terms of this modulation is also discussed. (author)

On the Automatic Parallelization of Sparse and Irregular Fortran Programs

Directory of Open Access Journals (Sweden)

Yuan Lin

1999-01-01

Full Text Available Automatic parallelization is usually believed to be less effective at exploiting implicit parallelism in sparse/irregular programs than in their dense/regular counterparts. However, not much is really known because there have been few research reports on this topic. In this work, we have studied the possibility of using an automatic parallelizing compiler to detect the parallelism in sparse/irregular programs. The study with a collection of sparse/irregular programs led us to some common loop patterns. Based on these patterns new techniques were derived that produced good speedups when manually applied to our benchmark codes. More importantly, these parallelization methods can be implemented in a parallelizing compiler and can be applied automatically.

NEOWISE: OBSERVATIONS OF THE IRREGULAR SATELLITES OF JUPITER AND SATURN

Energy Technology Data Exchange (ETDEWEB)

Grav, T. [Planetary Science Institute, Tucson, AZ 85719 (United States); Bauer, J. M.; Mainzer, A. K.; Masiero, J. R.; Sonnett, S.; Kramer, E. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Nugent, C. R.; Cutri, R. M., E-mail: tgrav@psi.edu [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States)

2015-08-10

We present thermal model fits for 11 Jovian and 3 Saturnian irregular satellites based on measurements from the WISE/NEOWISE data set. Our fits confirm spacecraft-measured diameters for the objects with in situ observations (Himalia and Phoebe) and provide diameters and albedo for 12 previously unmeasured objects, 10 Jovian and 2 Saturnian irregular satellites. The best-fit thermal model beaming parameters are comparable to what is observed for other small bodies in the outer solar system, while the visible, W1, and W2 albedos trace the taxonomic classifications previously established in the literature. Reflectance properties for the irregular satellites measured are similar to the Jovian Trojan and Hilda Populations, implying common origins.

Crime among irregular immigrants and the influence of internal border control

NARCIS (Netherlands)

Leerkes, A.S.; Engbersen, G.; Leun, van der J.P.

2012-01-01

Abstract Both the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular immigrants

Crime among irregular immigrants and the influence of internal border control

NARCIS (Netherlands)

A.S. Leerkes (Arjen); G.B.M. Engbersen (Godfried); J.P. van der Leun (Joanne)

2012-01-01

textabstractBoth the number of crime suspects without legal status and the number of irregular or undocumented immigrants held in detention facilities increased substantially in theNetherlands between 1997 and 2003. In this period, theDutch state increasingly attempted to exclude irregular

Selection of stationary phase particle geometry using X-ray computed tomography and computational fluid dynamics simulations.

Science.gov (United States)

Schmidt, Irma; Minceva, Mirjana; Arlt, Wolfgang

2012-02-17

The X-ray computed tomography (CT) is used to determine local parameters related to the column packing homogeneity and hydrodynamics in columns packed with spherically and irregularly shaped particles of same size. The results showed that the variation of porosity and axial dispersion coefficient along the column axis is insignificant, compared to their radial distribution. The methodology of using the data attained by CT measurements to perform a CFD simulation of a batch separation of model binary mixtures, with different concentration and separation factors is demonstrated. The results of the CFD simulation study show that columns packed with spherically shaped particles provide higher yield in comparison to columns packed with irregularly shaped particles only below a certain value of the separation factor. The presented methodology can be used for selecting a suited packing material for a particular separation task. Copyright © 2012 Elsevier B.V. All rights reserved.

Geostatistical regularization operators for geophysical inverse problems on irregular meshes

Science.gov (United States)

Jordi, C.; Doetsch, J.; Günther, T.; Schmelzbach, C.; Robertsson, J. OA

2018-05-01

Irregular meshes allow to include complicated subsurface structures into geophysical modelling and inverse problems. The non-uniqueness of these inverse problems requires appropriate regularization that can incorporate a priori information. However, defining regularization operators for irregular discretizations is not trivial. Different schemes for calculating smoothness operators on irregular meshes have been proposed. In contrast to classical regularization constraints that are only defined using the nearest neighbours of a cell, geostatistical operators include a larger neighbourhood around a particular cell. A correlation model defines the extent of the neighbourhood and allows to incorporate information about geological structures. We propose an approach to calculate geostatistical operators for inverse problems on irregular meshes by eigendecomposition of a covariance matrix that contains the a priori geological information. Using our approach, the calculation of the operator matrix becomes tractable for 3-D inverse problems on irregular meshes. We tested the performance of the geostatistical regularization operators and compared them against the results of anisotropic smoothing in inversions of 2-D surface synthetic electrical resistivity tomography (ERT) data as well as in the inversion of a realistic 3-D cross-well synthetic ERT scenario. The inversions of 2-D ERT and seismic traveltime field data with geostatistical regularization provide results that are in good accordance with the expected geology and thus facilitate their interpretation. In particular, for layered structures the geostatistical regularization provides geologically more plausible results compared to the anisotropic smoothness constraints.

Generating Performance Models for Irregular Applications

Energy Technology Data Exchange (ETDEWEB)

Friese, Ryan D.; Tallent, Nathan R.; Vishnu, Abhinav; Kerbyson, Darren J.; Hoisie, Adolfy

2017-05-30

Many applications have irregular behavior --- non-uniform input data, input-dependent solvers, irregular memory accesses, unbiased branches --- that cannot be captured using today's automated performance modeling techniques. We describe new hierarchical critical path analyses for the \\Palm model generation tool. To create a model's structure, we capture tasks along representative MPI critical paths. We create a histogram of critical tasks with parameterized task arguments and instance counts. To model each task, we identify hot instruction-level sub-paths and model each sub-path based on data flow, instruction scheduling, and data locality. We describe application models that generate accurate predictions for strong scaling when varying CPU speed, cache speed, memory speed, and architecture. We present results for the Sweep3D neutron transport benchmark; Page Rank on multiple graphs; Support Vector Machine with pruning; and PFLOTRAN's reactive flow/transport solver with domain-induced load imbalance.

Effects of magnetic storm phases on F layer irregularities below the auroral oval

International Nuclear Information System (INIS)

Aarons, J.; Gurgiolo, C.; Rodger, A.S.

1988-01-01

Observations of F-layer irregularity development and intensity were obtained between September and October 1981, primarily over subauroral latitudes in the area of the plasmapause. The results reveal the descent of the auroral irregularity region to include subauroral latitudes in the general area of the plasmapause during the main phases of a series of magnetic storms. Irregularities were found primarily at lower latitudes during the subauroral or plasmapause storm. A model for the subauroral irregularities in recovery phases of magnetic storms is proposed in which energy stored in the ring current is slowly released. 27 references

Dependence on zenith angle of the strength of 3-meter equatorial electrojet irregularities

International Nuclear Information System (INIS)

Ierkic, H.M.; Fejer, B.G.; Farley, D.T.

1980-01-01

Radar measurements in Peru were used to deduce the zenith angle dependence of the scattering cross section of plasma irregularities generated by instabilities in the equatorial electrojet. The irregularities probed by the 50 MHz Jicamarca radar had a wavelength of 3m. The cross section for the type 2 irregularities was isotopic in the plane perpendicular to the magnetic field, while the cross section for the stronger type 1 irregularities varied with zenith angle at a rate of approximately 0.3 dB/degree; the horizontally traveling waves were more than 100 times stronger than those traveling vertically

Spatial irregularities in Jupiter's upper ionosphere observed by voyager radio occultations

Energy Technology Data Exchange (ETDEWEB)

Hinson, D.P.; Tyler, G.L.

1982-07-01

Dual frequency radio occultation experiments carried out with Voyagers 1 and 2 provided data on the spatial irregularities in Jupiter's ionosphere at four different locations. Sample spectra of weak fluctuations in amplitude and phase of the 3.6-cm and 13-cm wavelength radio signals can be interpreted by using the theory for scattering from an anisotropic power law phase screen. Least squares solutions for ionospheric parameters derived from the observed fluctuation spectra yielded estimates of (1) the axial ratio, (2) angular orientation of the anisotropic irregularities, (3) the power law exponent of the spatial spectrum of irregularities, and (4) the magnitude of the spatial variations in electron density. Equipment limitations and the method of analysis constrain the observations to irregularities of approximate size 1--200 km. No evidence of the inner or outer scale of the irregularities was found. For length scales in the range given, the three-dimensional spatial spectrum obeys a power law with exponent varying from -3.0 to -3.7, and the root mean square fractional variations in electron density are 1--15%. All observed irregularities appear to be anisotropic with axial ratios between 2:1 and 10:1. Ionospheric parameters vary with altitude and latitude. We conclude that the measured angular orientation of the anisotropic irregularities indicates magnetic field direction and may provide a basis for refining Jovian magnetic field models.

Measurement of Dynamic Friction Coefficient on the Irregular Free Surface

International Nuclear Information System (INIS)

Yeom, S. H.; Seo, K. S.; Lee, J. H.; Lee, K. H.

2007-01-01

A spent fuel storage cask must be estimated for a structural integrity when an earthquake occurs because it freely stands on ground surface without a restriction condition. Usually the integrity estimation for a seismic load is performed by a FEM analysis, the friction coefficient for a standing surface is an important parameter in seismic analysis when a sliding happens. When a storage cask is placed on an irregular ground surface, measuring a friction coefficient of an irregular surface is very difficult because the friction coefficient is affected by the surface condition. In this research, dynamic friction coefficients on the irregular surfaces between a concrete cylinder block and a flat concrete slab are measured with two methods by one direction actuator

30 MHz radar observations of artificial E region field-aligned plasma irregularities

Directory of Open Access Journals (Sweden)

D. L. Hysell

2008-02-01

Full Text Available Artificial E region field aligned irregularities (FAIs have been observed during heating experiments at the HAARP facility using a new 30 MHz coherent scatter radar imager deployed near Homer, Alaska. Irregularities were observed during brief experiments on three quiet days in July and August, 2007, when the daytime E region critical frequency was close to 3 MHz. Irregularities were consistently generated and detected during experiments with O-mode HF pumping on zenith with a 1-min on, 1-min off CW modulation. The scattering cross sections, rise, and fall times of the echoes were observed as well as their spectral properties. Results were found to be mainly in agreement with observations from other mid- and high-latitude sites with some discrepancies. Radar images of the irregularity-filled volume on one case exhibited clear variations in backscatter power and Doppler shift across the volume. The images furthermore show the emergence of a small irregularity-filled region to the south southwest of the main region in the approximate direction of magnetic zenith.

Irregular menses: an independent risk factor for gestational diabetes mellitus.

Science.gov (United States)

Haver, Mary Claire; Locksmith, Gregory J; Emmet, Emily

2003-05-01

Our purpose was to determine whether a history of irregular menses predicts gestational diabetes mellitus independently of traditional risk factors. We analyzed demographic characteristics, body mass index, and menstrual history of 85 pregnant women with gestational diabetes mellitus and compared them with 85 systematically selected control subjects who were matched for age, race, and delivery year. Subjects with pregestational diabetes mellitus, previous gestational diabetes mellitus, family history of diabetes mellitus, weight >200 pounds, previous macrosomic infants, or previous stillbirth were excluded. Demographic characteristics between case and control groups were similar. Mean body mass index was higher among cases (26.5 kg/m(2)) versus control subjects (24.5 kg/m(2), P =.004). Irregular cycles were more prevalent in the cases (24% vs 7%, P =.006). With the use of body mass index as a stratification factor, menstrual irregularity maintained a strong association with gestational diabetes mellitus (P =.014). A history of irregular menstrual cycles was a significant independent predictor of gestational diabetes mellitus. If selective screening is implemented for gestational diabetes mellitus, such history should be considered in the decision of whom to test.

Backscatter measurements of 11-cm equatorial spread-F irregularities

International Nuclear Information System (INIS)

Tsunoda, R.T.

1980-01-01

In the equatorial F-region ionosphere, a turbulent cascade process has been found to exist that extends from irregularity spatial wavelengths longer than tens of kilometers down to wavelengths as short as 36 cm. To investigate the small-scale regime of wavelengths less than 36 cm, an equatorial radar experiment was conducted using a frequency of 1320 MHz that corresponds to an irregularity wavelength of 11 cm. The first observations of radar backscatter from 11-cm field-aligned irregularities (FAI) are described. These measurements extend the spatial wavelength regime of F-region FAI to lengths that approach both electron gyroradius and the Debye length. Agreement of these results with the theory of high-frequency drift waves suggests that these observations may be unique to the equatorial ionosphere. That is, the requirement of low electron densities for which the theroy calls may preclude the existence of 11-cm FAI elsewhere in the F-region ionosphere, except in equatorial plasma bubbles

Stromal haze, myofibroblasts, and surface irregularity after PRK.

Science.gov (United States)

Netto, Marcelo V; Mohan, Rajiv R; Sinha, Sunilima; Sharma, Ajay; Dupps, William; Wilson, Steven E

2006-05-01

The aim of this study was to investigate the relationship between the level of stromal surface irregularity after photorefractive keratectomy (PRK) and myofibroblast generation along with the development of corneal haze. Variable levels of stromal surface irregularity were generated in rabbit corneas by positioning a fine mesh screen in the path of excimer laser during ablation for a variable percentage of the terminal pulses of the treatment for myopia that does not otherwise generate significant opacity. Ninety-six rabbits were divided into eight groups: [see table in text]. Slit lamp analysis and haze grading were performed in all groups. Rabbits were sacrificed at 4 hr or 4 weeks after surgery and histochemical analysis was performed on corneas for apoptosis (TUNEL assay), myofibroblast marker alpha-smooth muscle actin (SMA), and integrin alpha4 to delineate the epithelial basement membrane. Slit-lamp grading revealed severe haze formation in corneas in groups IV and VI, with significantly less haze in groups II, III, and VII and insignificant haze compared with the unwounded control in groups I and V. Analysis of SMA staining at 4 weeks after surgery, the approximate peak of haze formation in rabbits, revealed low myofibroblast formation in group I (1.2+/-0.2 cells/400x field) and group V (1.8+/-0.4), with significantly more in groups II (3.5+/-1.8), III (6.8+/-1.6), VII (7.9+/-3.8), IV (12.4+/-4.2) and VI (14.6+/-5.1). The screened groups were significantly different from each other (p PRK groups. The -9.0 diopter PRK group VI had significantly more myofibroblast generation than the -9.0 diopter PRK with PTK-smoothing group VII (p PRK and the level of stromal surface irregularity. PTK-smoothing with methylcellulose was an effective method to reduce stromal surface irregularity and decreased both haze and associated myofibroblast density. We hypothesize that stromal surface irregularity after PRK for high myopia results in defective basement membrane

Criticality predicts maximum irregularity in recurrent networks of excitatory nodes.

Directory of Open Access Journals (Sweden)

Yahya Karimipanah

Full Text Available A rigorous understanding of brain dynamics and function requires a conceptual bridge between multiple levels of organization, including neural spiking and network-level population activity. Mounting evidence suggests that neural networks of cerebral cortex operate at a critical regime, which is defined as a transition point between two phases of short lasting and chaotic activity. However, despite the fact that criticality brings about certain functional advantages for information processing, its supporting evidence is still far from conclusive, as it has been mostly based on power law scaling of size and durations of cascades of activity. Moreover, to what degree such hypothesis could explain some fundamental features of neural activity is still largely unknown. One of the most prevalent features of cortical activity in vivo is known to be spike irregularity of spike trains, which is measured in terms of the coefficient of variation (CV larger than one. Here, using a minimal computational model of excitatory nodes, we show that irregular spiking (CV > 1 naturally emerges in a recurrent network operating at criticality. More importantly, we show that even at the presence of other sources of spike irregularity, being at criticality maximizes the mean coefficient of variation of neurons, thereby maximizing their spike irregularity. Furthermore, we also show that such a maximized irregularity results in maximum correlation between neuronal firing rates and their corresponding spike irregularity (measured in terms of CV. On the one hand, using a model in the universality class of directed percolation, we propose new hallmarks of criticality at single-unit level, which could be applicable to any network of excitable nodes. On the other hand, given the controversy of the neural criticality hypothesis, we discuss the limitation of this approach to neural systems and to what degree they support the criticality hypothesis in real neural networks. Finally

Target Tracking of a Linear Time Invariant System under Irregular Sampling

Directory of Open Access Journals (Sweden)

Jin Xue-Bo

2012-11-01

Full Text Available Due to event-triggered sampling in a system, or maybe with the aim of reducing data storage, tracking many applications will encounter irregular sampling time. By calculating the matrix exponential using an inverse Laplace transform, this paper transforms the irregular sampling tracking problem to the problem of tracking with time-varying parameters of a system. Using the common Kalman filter, the developed method is used to track a target for the simulated trajectory and video tracking. The results of simulation experiments have shown that it can obtain good estimation performance even at a very high irregular rate of measurement sampling time.

Light scattering at small angles by atmospheric irregular particles: modelling and laboratory measurements

Science.gov (United States)

Lurton, T.; Renard, J.-B.; Vignelles, D.; Jeannot, M.; Akiki, R.; Mineau, J.-L.; Tonnelier, T.

2014-04-01

We have investigated the behaviour of light scattering by particulates of various sizes (0.1 μm to 100 μm) at a small scattering angle (below 20°). It has been previously shown that, for a small angle, the scattered intensities are weakly dependent upon the particulates' composition (Renard et al., 2010). Particles found in the atmosphere exhibit roughness that leads to large discrepancies with the classical Mie solution in terms of scattered intensities in the low angular set-up. This article focuses on building an effective theoretical tool to predict the behaviour of light scattering by real particulates at a small scattering angle. We present both the classical Mie theory and its adaptation to the case of rough particulates with a fairly simple roughness parameterisation. An experimental device was built, corresponding to the angular set-up of interest (low scattering angle and therefore low angular aperture). Measurements are presented that confirm the theoretical results with good agreement. It was found that differences between the classical Mie solution and actual measurements - especially for large particulates - can be attributed to the particulate roughness. It was also found that, in this low angular set-up, saturation of the scattered intensities occurs for relatively small values of the roughness parameter. This confirms the low variability in the scattered intensities observed for atmospheric particulates of different kinds. A direct interest of this study is a broadening of the dynamic range of optical counters: using a small angle of aperture for measurements allows greater dynamics in terms of particle size. Thus it allows a single device to observe a broad range of particle sizes whilst utilising the same electronics.

Application of the pothole DAF method to vehicles traversing periodic roadway irregularities

Science.gov (United States)

Pesterev, A. V.; Bergman, L. A.; Tan, C. A.; Yang, B.

2005-01-01

This paper is a sequel to the work discussed in Pesterev et al. (Journal of Sound and Vibration, in press). In that paper, it was suggested that the technique to determine the effect of a local road surface irregularity on the dynamics of a vehicle modelled as a linear multi-degree-of-freedom system relies on the so-called pothole dynamic amplification factor (DAF), which is a complex-valued function specific to the irregularity shape. This paper discusses the companion problem of how to determine the DAF function for an irregularity represented as a superposition of simpler ones. Another purpose of this paper is to demonstrate the application of the pothole DAF functions technique to finding a priori estimates of the effect of irregularities with a repeated structure. Specifically, we solve the problem of finding the conditions under which the dynamic effect of two identical potholes located one after another is greater than that due to the single pothole. We also find the estimate for the number of periods of a periodic irregularity that are sufficient in order to consider the oscillator response as steady state. The discussions are illustrated by numerical examples.

Irregular singularities in Liouville theory and Argyres-Douglas type gauge theories, I

Energy Technology Data Exchange (ETDEWEB)

Gaiotto, D. [Institute for Advanced Study (IAS), Princeton, NJ (United States); Teschner, J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

2012-03-15

Motivated by problems arising in the study of N=2 supersymmetric gauge theories we introduce and study irregular singularities in two-dimensional conformal field theory, here Liouville theory. Irregular singularities are associated to representations of the Virasoro algebra in which a subset of the annihilation part of the algebra act diagonally. In this paper we define natural bases for the space of conformal blocks in the presence of irregular singularities, describe how to calculate their series expansions, and how such conformal blocks can be constructed by some delicate limiting procedure from ordinary conformal blocks. This leads us to a proposal for the structure functions appearing in the decomposition of physical correlation functions with irregular singularities into conformal blocks. Taken together, we get a precise prediction for the partition functions of some Argyres-Douglas type theories on S{sup 4}. (orig.)

Irregular singularities in Liouville theory and Argyres-Douglas type gauge theories, I

International Nuclear Information System (INIS)

Gaiotto, D.; Teschner, J.

2012-03-01

Motivated by problems arising in the study of N=2 supersymmetric gauge theories we introduce and study irregular singularities in two-dimensional conformal field theory, here Liouville theory. Irregular singularities are associated to representations of the Virasoro algebra in which a subset of the annihilation part of the algebra act diagonally. In this paper we define natural bases for the space of conformal blocks in the presence of irregular singularities, describe how to calculate their series expansions, and how such conformal blocks can be constructed by some delicate limiting procedure from ordinary conformal blocks. This leads us to a proposal for the structure functions appearing in the decomposition of physical correlation functions with irregular singularities into conformal blocks. Taken together, we get a precise prediction for the partition functions of some Argyres-Douglas type theories on S 4 . (orig.)

Agglomerates, smoke oxide particles, and carbon inclusions in condensed combustion products of an aluminized GAP-based propellant

Science.gov (United States)

Ao, Wen; Liu, Peijin; Yang, Wenjing

2016-12-01

In solid propellants, aluminum is widely used to improve the performance, however the condensed combustion products especially the large agglomerates generated from aluminum combustion significantly affect the combustion and internal flow inside the solid rocket motor. To clarify the properties of the condensed combustion products of aluminized propellants, a constant-pressure quench vessel was adopted to collect the combustion products. The morphology and chemical compositions of the collected products, were then studied by using scanning electron microscopy coupled with energy dispersive (SEM-EDS) method. Various structures have been observed in the condensed combustion products. Apart from the typical agglomerates or smoke oxide particles observed before, new structures including the smoke oxide clusters, irregular agglomerates and carbon-inclusions are discovered and investigated. Smoke oxide particles have the highest amount in the products. The highly dispersed oxide particle is spherical with very smooth surface and is on the order of 1-2 μm, but due to the high temperature and long residence time, these small particles will aggregate into smoke oxide clusters which are much larger than the initial particles. Three types of spherical agglomerates have been found. As the ambient gas temperature is much higher than the boiling point of Al2O3, the condensation layer inside which the aluminum drop is burning would evaporate quickly, which result in the fact that few "hollow agglomerates" has been found compared to "cap agglomerates" and "solid agglomerates". Irregular agglomerates usually larger than spherical agglomerates. The formation of irregular agglomerates likely happens by three stages: deformation of spherical aluminum drops; combination of particles with various shape; finally production of irregular agglomerates. EDS results show the ratio of O to Al on the surface of agglomerates is lower in comparison to smoke oxide particles. C and O account for

Effects of surface irregularities on intensity data from laser scanning: an experimental approach.

Directory of Open Access Journals (Sweden)

G. Teza

2008-06-01

Full Text Available The results of an experiment carried out with the aim to investigate the role of surface irregularities on the intensity data provided by a terrestrial laser scanner (TLS survey are reported here. Depending on surface roughness, the interaction between an electromagnetic wave and microscopic irregularities leads to a Lambertian-like diffusive light reflection, allowing the TLS to receive the backscattered component of the signal. The described experiment consists in a series of TLS-based acquisitions of a rotating artificial target specifically conceived in order to highlight the effects on the intensity data due to surface irregularity. This target is articulated in a flat plate and in an irregular surface, whose macro-roughness has a characteristic length with the same order of the spot size. Results point out the different behavior of the plates. The intensity of the signal backscattered by the planar element decreases if the incidence angle increases, whereas the intensity of the signal backscattered by the irregular surface is almost constant if the incidence angle varies. Since the typical surfaces acquired in a geological/geophysical survey are generally irregular, these results imply that the intensity data can be easily used in order to evaluate the reflectance of the material at the considered wavelength, e.g. for pattern recognition purposes.

Radar Observations of 8.3-m scale equatorial spread F irregularities over Trivandrum

Directory of Open Access Journals (Sweden)

D. Tiwari

2004-03-01

Full Text Available In this paper, we present observations of equatorial spread F (ESF irregularities made using a newly installed 18MHz radar located at Trivandrum. We characterize the morphology and the spectral parameters of the 8.3-m ESF irregularities which are found to be remarkably different from that observed so extensively at the 3-m scale size. We also present statistical results of the irregularities in the form of percentage occurrence of the echoes and spectral parameters (SNR, Doppler velocity, Spectral width. The Doppler spectra are narrower, less structured and less variable in time as compared to those observed for 3-m scale size. We have never observed the ESF irregularity velocities to be supersonic here unlike those at Jicamarca, and the velocities are found to be within ±200ms–1. The spectral widths are found to be less than 150ms–1. Hence, the velocities and spectral width both are smaller than those reported for 3-m scale size. The velocities and spectral widths are further found to be much smaller than those of the American sector. These observations are compared with those reported elsewhere and discussed in the light of present understanding on the ESF irregularities at different wavelengths. Key words. Ionoshphere (equatorial ionosphere, plasma waves and instabilities; ionospheric irregularities

Modification of transmission dose algorithm for irregularly shaped radiation field and tissue deficit

Energy Technology Data Exchange (ETDEWEB)

Yun, Hyong Geon; Shin, Kyo Chul [Dankook Univ., College of Medicine, Seoul (Korea, Republic of); Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan [Seoul National Univ., College of Medicine, Seoul (Korea, Republic of); Lee, Hyoung Koo [The Catholic Univ., College of Medicine, Seoul (Korea, Republic of)

2002-07-01

Algorithm for estimation of transmission dose was modified for use in partially blocked radiation fields and in cases with tissue deficit. The beam data was measured with flat solid phantom in various conditions of beam block. And an algorithm for correction of transmission dose in cases of partially blocked radiation field was developed from the measured data. The algorithm was tested in some clinical settings with irregular shaped field. Also, another algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. This algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients by using multiple sheets of solid phantoms. The algorithm for correction of beam block could accurately reflect the effect of beam block, with error within {+-}1.0%, both with square fields and irregularly shaped fields. The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within {+-}1.0% in most situations and within {+-}3.0% in experimental settings with irregular contours mimicking breast cancer treatment set-up. Developed algorithms could accurately estimate the transmission dose in most radiation treatment settings including irregularly shaped field and irregularly shaped body contour with tissue deficit in transmission dosimetry.

Modification of transmission dose algorithm for irregularly shaped radiation field and tissue deficit

International Nuclear Information System (INIS)

Yun, Hyong Geon; Shin, Kyo Chul; Huh, Soon Nyung; Woo, Hong Gyun; Ha, Sung Whan; Lee, Hyoung Koo

2002-01-01

Algorithm for estimation of transmission dose was modified for use in partially blocked radiation fields and in cases with tissue deficit. The beam data was measured with flat solid phantom in various conditions of beam block. And an algorithm for correction of transmission dose in cases of partially blocked radiation field was developed from the measured data. The algorithm was tested in some clinical settings with irregular shaped field. Also, another algorithm for correction of transmission dose for tissue deficit was developed by physical reasoning. This algorithm was tested in experimental settings with irregular contours mimicking breast cancer patients by using multiple sheets of solid phantoms. The algorithm for correction of beam block could accurately reflect the effect of beam block, with error within ±1.0%, both with square fields and irregularly shaped fields. The correction algorithm for tissue deficit could accurately reflect the effect of tissue deficit with errors within ±1.0% in most situations and within ±3.0% in experimental settings with irregular contours mimicking breast cancer treatment set-up. Developed algorithms could accurately estimate the transmission dose in most radiation treatment settings including irregularly shaped field and irregularly shaped body contour with tissue deficit in transmission dosimetry

PERIODIC ORBIT FAMILIES IN THE GRAVITATIONAL FIELD OF IRREGULAR-SHAPED BODIES

Energy Technology Data Exchange (ETDEWEB)

Jiang, Yu [State Key Laboratory of Astronautic Dynamics, Xi’an Satellite Control Center, Xi’an 710043 (China); Baoyin, Hexi, E-mail: jiangyu_xian_china@163.com [School of Aerospace Engineering, Tsinghua University, Beijing 100084 (China)

2016-11-01

The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.

PERIODIC ORBIT FAMILIES IN THE GRAVITATIONAL FIELD OF IRREGULAR-SHAPED BODIES

International Nuclear Information System (INIS)

Jiang, Yu; Baoyin, Hexi

2016-01-01

The discovery of binary and triple asteroids in addition to the execution of space missions to minor celestial bodies in the past several years have focused increasing attention on periodic orbits around irregular-shaped celestial bodies. In the present work, we adopt a polyhedron shape model for providing an accurate representation of irregular-shaped bodies and employ the model to calculate their corresponding gravitational and effective potentials. We also investigate the characteristics of periodic orbit families and the continuation of periodic orbits. We prove a fact, which provides a conserved quantity that permits restricting the number of periodic orbits in a fixed energy curved surface about an irregular-shaped body. The collisions of Floquet multipliers are maintained during the continuation of periodic orbits around the comet 1P/Halley. Multiple bifurcations in the periodic orbit families about irregular-shaped bodies are also discussed. Three bifurcations in the periodic orbit family have been found around the asteroid 216 Kleopatra, which include two real saddle bifurcations and one period-doubling bifurcation.

Short-term magnetic field alignment variations of equatorial ionospheric irregularities

International Nuclear Information System (INIS)

Johnson, A.L.

1988-01-01

The ionospheric irregularities that cause equatorial scintillation are elongated along the north-south magnetic field lines. During a 1981 field campaign at Ascension Island, 250-MHz receivers were spaced from 300 m to 1.6 km along the field lines, and the signals received from the Marisat satellite were cross correlated. Data collected during eight nights of fading showed a linear relationship between fading rate and cross correlation. The alignment of the antennas was adjusted to give a zero time lag between the widely spaced receivers with a measurement accuracy of 0.03 s. Since the average irregularity velocity was 125 m/s, this time accuracy translated to an angular measurement accuracy of 0.1 deg. During a 4-hour period of nightly fading, occasional differences in time of arrival were noted that corresponded to a tilt in the north-south alignment of + or - 1 deg. Data from several nights of fading were analyzed, and each night exhibited the same variance in the north-south irregularity alignment. It is postulated that the shift in the measured peak correlation may have been caused by patches of irregularities at different altitudes where the magnetic field lines have a slightly different direction. 13 references

On the Total Edge Irregularity Strength of Generalized Butterfly Graph

Science.gov (United States)

Dwi Wahyuna, Hafidhyah; Indriati, Diari

2018-04-01

Let G(V, E) be a connected, simple, and undirected graph with vertex set V and edge set E. A total k-labeling is a map that carries vertices and edges of a graph G into a set of positive integer labels {1, 2, …, k}. An edge irregular total k-labeling λ: V(G) ∪ E(G) → {1, 2, …, k} of a graph G is a total k-labeling such that the weights calculated for all edges are distinct. The weight of an edge uv in G, denoted by wt(uv), is defined as the sum of the label of u, the label of v, and the label of uv. The total edge irregularity strength of G, denoted by tes(G), is the minimum value of the largest label k over all such edge irregular total k-labelings. A generalized butterfly graph, BFn , obtained by inserting vertices to every wing with assumption that sum of inserting vertices to every wing are same then it has 2n + 1 vertices and 4n ‑ 2 edges. In this paper, we investigate the total edge irregularity strength of generalized butterfly graph, BFn , for n > 2. The result is tes(B{F}n)=\\lceil \\frac{4n}{3}\\rceil .

Exploring Manycore Multinode Systems for Irregular Applications with FPGA Prototyping

Energy Technology Data Exchange (ETDEWEB)

Ceriani, Marco; Palermo, Gianluca; Secchi, Simone; Tumeo, Antonino; Villa, Oreste

2013-04-29

We present a prototype of a multi-core architecture implemented on FPGA, designed to enable efficient execution of irregular applications on distributed shared memory machines, while maintaining high performance on regular workloads. The architecture is composed of off-the-shelf soft-core cores, local interconnection and memory interface, integrated with custom components that optimize it for irregular applications. It relies on three key elements: a global address space, multithreading, and fine-grained synchronization. Global addresses are scrambled to reduce the formation of network hot-spots, while the latency of the transactions is covered by integrating an hardware scheduler within the custom load/store buffers to take advantage from the availability of multiple executions threads, increasing the efficiency in a transparent way to the application. We evaluated a dual node system irregular kernels showing scalability in the number of cores and threads.

Seismic performance for vertical geometric irregularity frame structures

Science.gov (United States)

Ismail, R.; Mahmud, N. A.; Ishak, I. S.

2018-04-01

This research highlights the result of vertical geometric irregularity frame structures. The aid of finite element analysis software, LUSAS was used to analyse seismic performance by focusing particularly on type of irregular frame on the differences in height floors and continued in the middle of the building. Malaysia’s building structures were affected once the earthquake took place in the neighbouring country such as Indonesia (Sumatera Island). In Malaysia, concrete is widely used in building construction and limited tension resistance to prevent it. Analysing structural behavior with horizontal and vertical static load is commonly analyses by using the Plane Frame Analysis. The case study of this research is to determine the stress and displacement in the seismic response under this type of irregular frame structures. This study is based on seven-storey building of Clinical Training Centre located in Sungai Buloh, Selayang, Selangor. Since the largest earthquake occurs in Acheh, Indonesia on December 26, 2004, the data was recorded and used in conducting this research. The result of stress and displacement using IMPlus seismic analysis in LUSAS Modeller Software under the seismic response of a formwork frame system states that the building is safe to withstand the ground and in good condition under the variation of seismic performance.

Simulating Seismic Wave Propagation in Viscoelastic Media with an Irregular Free Surface

Science.gov (United States)

Liu, Xiaobo; Chen, Jingyi; Zhao, Zhencong; Lan, Haiqiang; Liu, Fuping

2018-05-01

In seismic numerical simulations of wave propagation, it is very important for us to consider surface topography and attenuation, which both have large effects (e.g., wave diffractions, conversion, amplitude/phase change) on seismic imaging and inversion. An irregular free surface provides significant information for interpreting the characteristics of seismic wave propagation in areas with rugged or rapidly varying topography, and viscoelastic media are a better representation of the earth's properties than acoustic/elastic media. In this study, we develop an approach for seismic wavefield simulation in 2D viscoelastic isotropic media with an irregular free surface. Based on the boundary-conforming grid method, the 2D time-domain second-order viscoelastic isotropic equations and irregular free surface boundary conditions are transferred from a Cartesian coordinate system to a curvilinear coordinate system. Finite difference operators with second-order accuracy are applied to discretize the viscoelastic wave equations and the irregular free surface in the curvilinear coordinate system. In addition, we select the convolutional perfectly matched layer boundary condition in order to effectively suppress artificial reflections from the edges of the model. The snapshot and seismogram results from numerical tests show that our algorithm successfully simulates seismic wavefields (e.g., P-wave, Rayleigh wave and converted waves) in viscoelastic isotropic media with an irregular free surface.

Radar Observations of 8.3-m scale equatorial spread F irregularities over Trivandrum

Directory of Open Access Journals (Sweden)

D. Tiwari

2004-03-01

Full Text Available In this paper, we present observations of equatorial spread F (ESF irregularities made using a newly installed 18MHz radar located at Trivandrum. We characterize the morphology and the spectral parameters of the 8.3-m ESF irregularities which are found to be remarkably different from that observed so extensively at the 3-m scale size. We also present statistical results of the irregularities in the form of percentage occurrence of the echoes and spectral parameters (SNR, Doppler velocity, Spectral width. The Doppler spectra are narrower, less structured and less variable in time as compared to those observed for 3-m scale size. We have never observed the ESF irregularity velocities to be supersonic here unlike those at Jicamarca, and the velocities are found to be within ±200ms^–1. The spectral widths are found to be less than 150ms^–1. Hence, the velocities and spectral width both are smaller than those reported for 3-m scale size. The velocities and spectral widths are further found to be much smaller than those of the American sector. These observations are compared with those reported elsewhere and discussed in the light of present understanding on the ESF irregularities at different wavelengths.

Key words. Ionoshphere (equatorial ionosphere, plasma waves and instabilities; ionospheric irregularities

Efficient irregular wavefront propagation algorithms on Intel® Xeon Phi™

OpenAIRE

Gomes, Jeremias M.; Teodoro, George; de Melo, Alba; Kong, Jun; Kurc, Tahsin; Saltz, Joel H.

2015-01-01

We investigate the execution of the Irregular Wavefront Propagation Pattern (IWPP), a fundamental computing structure used in several image analysis operations, on the Intel® Xeon Phi™ co-processor. An efficient implementation of IWPP on the Xeon Phi is a challenging problem because of IWPP’s irregularity and the use of atomic instructions in the original IWPP algorithm to resolve race conditions. On the Xeon Phi, the use of SIMD and vectorization instructions is critical to attain high perfo...

Irregular menses predicts ovarian cancer: Prospective evidence from the Child Health and Development Studies.

Science.gov (United States)

Cirillo, Piera M; Wang, Erica T; Cedars, Marcelle I; Chen, Lee-May; Cohn, Barbara A

2016-09-01

We tested the hypothesis that irregular menstruation predicts lower risk for ovarian cancer, possibly due to less frequent ovulation. We conducted a 50-year prospective study of 15,528 mothers in the Child Health and Development Studies cohort recruited from the Kaiser Foundation Health Plan from 1959 to 1966. Irregular menstruation was classified via medical record and self-report at age 26. We identified 116 cases and 84 deaths due to ovarian cancer through 2011 via linkage to the California Cancer Registry and Vital Statistics. Contrary to expectation, women with irregular menstrual cycles had a higher risk of ovarian cancer incidence and mortality over the 50-year follow-up. Associations increased with age (p irregular menstruation and ovarian cancer-we unexpectedly found higher risk for women with irregular cycles. These women are easy to identify and many may have polycystic ovarian syndrome. Classifying high-risk phenotypes such as irregular menstruation creates opportunities to find novel early biomarkers, refine clinical screening protocols and potentially develop new risk reduction strategies. These efforts can lead to earlier detection and better survival for ovarian cancer. © 2016 UICC.

Comparison of correlation analysis techniques for irregularly sampled time series

Directory of Open Access Journals (Sweden)

K. Rehfeld

2011-06-01

Full Text Available Geoscientific measurements often provide time series with irregular time sampling, requiring either data reconstruction (interpolation or sophisticated methods to handle irregular sampling. We compare the linear interpolation technique and different approaches for analyzing the correlation functions and persistence of irregularly sampled time series, as Lomb-Scargle Fourier transformation and kernel-based methods. In a thorough benchmark test we investigate the performance of these techniques.

All methods have comparable root mean square errors (RMSEs for low skewness of the inter-observation time distribution. For high skewness, very irregular data, interpolation bias and RMSE increase strongly. We find a 40 % lower RMSE for the lag-1 autocorrelation function (ACF for the Gaussian kernel method vs. the linear interpolation scheme,in the analysis of highly irregular time series. For the cross correlation function (CCF the RMSE is then lower by 60 %. The application of the Lomb-Scargle technique gave results comparable to the kernel methods for the univariate, but poorer results in the bivariate case. Especially the high-frequency components of the signal, where classical methods show a strong bias in ACF and CCF magnitude, are preserved when using the kernel methods.

We illustrate the performances of interpolation vs. Gaussian kernel method by applying both to paleo-data from four locations, reflecting late Holocene Asian monsoon variability as derived from speleothem δ¹⁸O measurements. Cross correlation results are similar for both methods, which we attribute to the long time scales of the common variability. The persistence time (memory is strongly overestimated when using the standard, interpolation-based, approach. Hence, the Gaussian kernel is a reliable and more robust estimator with significant advantages compared to other techniques and suitable for large scale application to paleo-data.

Design and scale-up of a semi-industrial downer-reactor for the rounding of irregular polymer particles

Energy Technology Data Exchange (ETDEWEB)

Sachs, Marius; Schmidt, Jochen; Peukert, Wolfgang; Wirth, Karl-Ernst [Friedrich-Alexander-Universität Erlangen-Nürnberg, Institute of Particle Technology, Cauerstr. 4, D-91058 Erlangen (Germany)

2016-03-09

The recent development of rapid prototyping technologies towards additive manufacturing reveals some major drawbacks of processes such as laser beam melting (LBM). This contribution focuses on the lack of suitable polymer material with a fine particle size and good flowability. Polymer particles obtained by a wet grinding process 1 are treated in a heated downer reactor. This treatment changes the particles’ morphology from a chiselled state towards a spherical form by surface tension forces in a molten state 2 and leads to an improved flowability. To reach the required amount of rounded polymer powder, a downer reactor in semi-industrial scale has been established and will be characterized in this article. For the purpose of particle rounding it is necessary to avoid contact of molten particles with each other and with the hot reactor walls. Furthermore, the heat distribution has been investigated as one of the key parameters of the process. Finally, a proof of concept by rounding wet grinded PBT material was successfully conducted. The product was examined to obtain data about a change in particle size and flowability.

Optimized Irregular Low-Density Parity-Check Codes for Multicarrier Modulations over Frequency-Selective Channels

Directory of Open Access Journals (Sweden)

Valérian Mannoni

2004-09-01

Full Text Available This paper deals with optimized channel coding for OFDM transmissions (COFDM over frequency-selective channels using irregular low-density parity-check (LDPC codes. Firstly, we introduce a new characterization of the LDPC code irregularity called “irregularity profile.” Then, using this parameterization, we derive a new criterion based on the minimization of the transmission bit error probability to design an irregular LDPC code suited to the frequency selectivity of the channel. The optimization of this criterion is done using the Gaussian approximation technique. Simulations illustrate the good performance of our approach for different transmission channels.

Drug Intoxicated Irregular Fighters: Complications, Dangers, and Responses

National Research Council Canada - National Science Library

Kan, Paul R

2008-01-01

.... Drug consumption in contemporary wars has coincided with the use of child soldiers, has led to increased unpredictability among irregular fighters, provided the conditions for the breakdown of social...

Artificial periodic irregularities in the auroral ionosphere

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M. T. Rietveld

1996-12-01

Full Text Available Artificial periodic irregularities (API are produced in the ionospheric plasma by a powerful standing electromagnetic wave reflected off the F region. The resulting electron-density irregularities can scatter other high-frequency waves if the Bragg scattering condition is met. Such measurements have been performed at mid-latitudes for two decades and have been developed into a useful ionospheric diagnostic technique. We report here the first measurements from a high-latitude station, using the EISCAT heating facility near Tromsø, Norway. Both F-region and lower-altitude ionospheric echoes have been obtained, but the bulk of the data has been in the E and D regions with echoes extending down to 52-km altitude. Examples of API are shown, mainly from the D region, together with simultaneous VHF incoherent-scatter-radar (ISR data. Vertical velocities derived from the rate of phase change during the irregularity decay are shown and compared with velocities derived from the ISR. Some of the API-derived velocities in the 75–115-km height range appear consistent with vertical neutral winds as shown by their magnitudes and by evidence of gravity waves, while other data in the 50–70-km range show an unrealistically large bias. For a comparison with ISR data it has proved difficult to get good quality data sets overlapping in height and time. The initial comparisons show some agreement, but discrepancies of several metres per second do not yet allow us to conclude that the two techniques are measuring the same quantity. The irregularity decay time-constants between about 53 and 70 km are compared with the results of an advanced ion-chemistry model, and height profiles of recorded signal power are compared with model estimates in the same altitude range. The calculated amplitude shows good agreement with the data in that the maximum occurs at about the same height as that of the measured amplitude. The calculated time-constant agrees very well with the

Kilometer-Spaced GNSS Array for Ionospheric Irregularity Monitoring

Science.gov (United States)

Su, Yang

This dissertation presents automated, systematic data collection, processing, and analysis methods for studying the spatial-temporal properties of Global Navigation Satellite Systems (GNSS) scintillations produced by ionospheric irregularities at high latitudes using a closely spaced multi-receiver array deployed in the northern auroral zone. The main contributions include 1) automated scintillation monitoring, 2) estimation of drift and anisotropy of the irregularities, 3) error analysis of the drift estimates, and 4) multi-instrument study of the ionosphere. A radio wave propagating through the ionosphere, consisting of ionized plasma, may suffer from rapid signal amplitude and/or phase fluctuations known as scintillation. Caused by non-uniform structures in the ionosphere, intense scintillation can lead to GNSS navigation and high-frequency (HF) communication failures. With specialized GNSS receivers, scintillation can be studied to better understand the structure and dynamics of the ionospheric irregularities, which can be parameterized by altitude, drift motion, anisotropy of the shape, horizontal spatial extent and their time evolution. To study the structuring and motion of ionospheric irregularities at the sub-kilometer scale sizes that produce L-band scintillations, a closely-spaced GNSS array has been established in the auroral zone at Poker Flat Research Range, Alaska to investigate high latitude scintillation and irregularities. Routinely collecting low-rate scintillation statistics, the array database also provides 100 Hz power and phase data for each channel at L1/L2C frequency. In this work, a survey of seasonal and hourly dependence of L1 scintillation events over the course of a year is discussed. To efficiently and systematically study scintillation events, an automated low-rate scintillation detection routine is established and performed for each day by screening the phase scintillation index. The spaced-receiver technique is applied to cross

Irregular ionization and scintillation of the ionosphere in equator region

International Nuclear Information System (INIS)

Shinno, Kenji

1974-01-01

The latest studies on the scintillation in satellite communication and its related irregularities of ionosphere are reviewed. They were made clear by means of spread-F, the direct measurement with scientific satellites, VHF radar observation, and radio wave propagation in equator region. The fundamental occurrence mechanism may be instability of plasma caused by the interaction of movement of neutral atmosphere and magnetic field. Comparison of the main characteristics of scintillation, namely the dependence on region, solar activity, season, local time, geomagnetic activity, movement in ionosphere, scattering source, frequency and transmission mode, was made and the correlation among spread-F, TEP and scintillation was summarized. The latest principal studies were the observations made by Intelsat and by ATS. Scintillation of Syncom-3 and Intelsat-II-F2 and spread-F by ionosphere observation were compared by Huang. It is reasonable to consider that the occurrence of scintillation is caused by the irregularities in ionosphere which are particular in equator region, because of the similar characteristics of spread-F and VHF propagation in the equator region. These three phenomena may occur in relation to the irregularities of ionosphere. Interpretation of spread-F and the abnormal propagation wave across the equator are given. The study using VHF radar and the movement of irregular ionization by the direct observation with artificial satellites are reviewd. (Iwakiri, K.)

Irregular Warfare: New Challenges for Civil-Military Relations

National Research Council Canada - National Science Library

Cronin, Patrick M

2008-01-01

.... Irregular warfare introduces new complications to what Eliot Cohen has called an unequal dialogue between civilian and military leaders in which civilian leaders hold the true power but must modulate...

Investigation on the cohesive silt/clay-particle sediment via the coupled CFD-DEM simulations

Science.gov (United States)

Xu, S.; Sun, H.; Sun, R.

2017-12-01

Sedimentation of silt/clay particles happens ubiquitously in nature and engineering field. There have been abundant studies focusing on the settling velocity of the cohesive particles, while studies on the sediment deposited from silt/clay irregular particles, including the vertical concentration profile of sediment and the various forces among the deposited particles are still lacking. This paper aims to investigate the above topics by employing the CFD-DEM (Computational Fluid Dynamics-Discrete Element Method) simulations. In this work, we simulate the settling of the mono- and poly- dispersed silt/clay particles and mainly study the characteristics of the deposited cohesive sediment. We use the bonded particles to simulate the irregular silt/clay aggregates at the initial state and utilize the van der Waals force for all micro-particles to consider the cohesive force among silt/clay particles. The interparticle collision force and the fluid-particle interaction forces are also considered in our numerical model. The value of the mean structural density of cohesive sediment obtained from simulations is in good agreement with the previous research, and it is obviously smaller than no-cohesive sediment because of the existence of the silt/clay flocs. Moreover, the solid concentration of sediment increases with the growth of the depth. It is because the silt/clay flocs are more easily to break up due to the gradually increased submerged gravity of the deposited particles along the depth. We also obtain the noncontacted cohesive force and contact force profiles during the sedimentation and the self-weight consolidation process. The study of the concentration profile and the forces among silt/clay sediment will help to give an accurate initial condition for calculating the speed of the reconsolidation process by employing the artificial loads, which is necessary for practical designs of the land reclamation projects.

Method of determining effects of heat-induced irregular refractive index on an optical system.

Science.gov (United States)

Song, Xifa; Li, Lin; Huang, Yifan

2015-09-01

The effects of an irregular refractive index on optical performance are examined. A method was developed to express a lens's irregular refractive index distribution. An optical system and its mountings were modeled by a thermomechanical finite element (FE) program in the predicted operating temperature range, -45°C-50°C. FE outputs were elaborated using a MATLAB optimization routine; a nonlinear least squares algorithm was adopted to determine which gradient equation best fit each lens's refractive index distribution. The obtained gradient data were imported into Zemax for sequential ray-tracing analysis. The root mean square spot diameter, modulation transfer function, and diffraction ensquared energy were computed for an optical system under an irregular refractive index and under thermoelastic deformation. These properties are greatly reduced by the irregular refractive index effect, which is one-third to five-sevenths the size of the thermoelastic deformation effect. Thus, thermal analyses of optical systems should consider not only thermoelastic deformation but also refractive index irregularities caused by inhomogeneous temperature.

Significance of scatter radar studies of E and F region irregularities at high latitudes

International Nuclear Information System (INIS)

Greenwald, R.A.

1983-01-01

This chapter considers the mechanisms by which electron density irregularities may be generated in the high latitude ionosphere and the techniques through which they are observed with ground base radars. The capabilities of radars used for studying these irregularities are compared with the capabilities of radars used for incoherent scatter measurements. The use of irregularity scatter techniques for dynamic studies of larger scale structured phenomena is discussed. Topics considered include E-region irregularities, observations with auroral radars, plasma drifts associated with a westward travelling surge, and ionospheric plasma motions associated with resonant waves. It is shown why high latitude F-region irregularity studies must be made in the HF frequency band (3-30 MHz). The joint use of the European Incoherent Scatter Association (EISCAT), STARE and SAFARI facilities is examined, and it is concluded that the various techniques will enhance each other and provide a better understanding of the various processes being studied

[Comparision of Different Methods of Area Measurement in Irregular Scar].

Science.gov (United States)

Ran, D; Li, W J; Sun, Q G; Li, J Q; Xia, Q

2016-10-01

To determine a measurement standard of irregular scar area by comparing the advantages and disadvantages of different measurement methods in measuring same irregular scar area. Irregular scar area was scanned by digital scanning and measured by coordinate reading method, AutoCAD pixel method, Photoshop lasso pixel method, Photoshop magic bar filled pixel method and Foxit PDF reading software, and some aspects of these methods such as measurement time, repeatability, whether could be recorded and whether could be traced were compared and analyzed. There was no significant difference in the scar areas by the measurement methods above. However, there was statistical difference in the measurement time and repeatability by one or multi performers and only Foxit PDF reading software could be traced back. The methods above can be used for measuring scar area, but each one has its advantages and disadvantages. It is necessary to develop new measurement software for forensic identification. Copyright© by the Editorial Department of Journal of Forensic Medicine

Irregular flowering patterns in terrestrial orchids: theories vs. empirical data

Directory of Open Access Journals (Sweden)

P. Kindlmann

2001-11-01

Full Text Available Empirical data on many species of terrestrial orchids suggest that their between-year flowering pattern is extremely irregular and unpredictable. A long search for the reason has hitherto proved inconclusive. Here we summarise and critically review the hypotheses that were put forward as explanations of this phenomenon: irregular flowering was attributed to costs associated with sexual reproduction, to herbivory, or to the chaotic behaviour of the system represented by difference equations describing growth of the vegetative and reproductive organs. None of these seems to explain fully the events of a transition from flowering one year to sterility or absence the next year. Data on the seasonal growth of leaves and inflorescence of two terrestrial orchid species, Epipactis albensis and Dactylorhiza fuchsii and our previous results are then used here to fill gaps in what has been published until now and to test alternative explanations of the irregular flowering patterns of orchids.

New prospective 4D-CT for mitigating the effects of irregular respiratory motion

Science.gov (United States)

Pan, Tinsu; Martin, Rachael M.; Luo, Dershan

2017-08-01

Artifact caused by irregular respiration is a major source of error in 4D-CT imaging. We propose a new prospective 4D-CT to mitigate this source of error without new hardware, software or off-line data-processing on the GE CT scanner. We utilize the cine CT scan in the design of the new prospective 4D-CT. The cine CT scan at each position can be stopped by the operator when an irregular respiration occurs, and resumed when the respiration becomes regular. This process can be repeated at one or multiple scan positions. After the scan, a retrospective reconstruction is initiated on the CT console to reconstruct only the images corresponding to the regular respiratory cycles. The end result is a 4D-CT free of irregular respiration. To prove feasibility, we conducted a phantom and six patient studies. The artifacts associated with the irregular respiratory cycles could be removed from both the phantom and patient studies. A new prospective 4D-CT scanning and processing technique to mitigate the impact of irregular respiration in 4D-CT has been demonstrated. This technique can save radiation dose because the repeat scans are only at the scan positions where an irregular respiration occurs. Current practice is to repeat the scans at all positions. There is no cost to apply this technique because it is applicable on the GE CT scanner without new hardware, software or off-line data-processing.

Observations of inner plasmasphere irregularities with a satellite-beacon radio-interferometer array

International Nuclear Information System (INIS)

Jacobson, A.R.; Hoogeveen, G.; Carlos, R.C.; Wu, G.; Fejer, B.G.; Kelley, M.C.

1996-01-01

A radio-interferometer array illuminated by 136-MHz beacons of several geosynchronous satellites has been used to study small (≥10 13 m -2 ) transient disturbances in the total electron content along the lines of sight to the satellites. High-frequency (f>3 mHz) electron content oscillations are persistently observed, particularly during night and particularly during geomagnetically disturbed periods. The oscillations move across the array plane at speeds in the range 200 endash 2000 m/s, with propagation azimuths that are strongly peaked in lobes toward the western half-plane. Detailed analysis of this azimuth behavior, involving comparison between observations on various satellite positions, indicates compellingly that the phase oscillations originate in radio refraction due to geomagnetically aligned plasma density perturbations in the inner plasmasphere. The motion of the phase perturbations across the array plane is caused by EXB drift of the plasma medium in which the irregularities are embedded. We review the statistics of 2.5 years of around-the-clock data on the local time, magnetic disturbance, seasonal, and line-of-sight variations of these observed irregularities. We compare the irregularities close-quote inferred electrodynamic drifts to what is known about midlatitude plasma drift from incoherent scatter. Finally, we show in detail how the observation of these irregularities provides a unique and complementary monitor of inner plasmasphere irregularity incidence and zonal drift.copyright 1996 American Geophysical Union

Spatio-temporal patterns of sediment particle movement on 2D and 3D bedforms

Science.gov (United States)

Tsubaki, Ryota; Baranya, Sándor; Muste, Marian; Toda, Yuji

2018-06-01

An experimental study was conducted to explore sediment particle motion in an open channel and its relationship to bedform characteristics. High-definition submersed video cameras were utilized to record images of particle motion over a dune's length scale. Image processing was conducted to account for illumination heterogeneity due to bedform geometric irregularity and light reflection at the water's surface. Identification of moving particles using a customized algorithm was subsequently conducted and then the instantaneous velocity distribution of sediment particles was evaluated using particle image velocimetry. Obtained experimental results indicate that the motion of sediment particles atop dunes differs depending on dune geometry (i.e., two-dimensional or three-dimensional, respectively). Sediment motion and its relationship to dune shape and dynamics are also discussed.

Influence of long-wavelength track irregularities on the motion of a high-speed train

Science.gov (United States)

Hung, C. F.; Hsu, W. L.

2018-01-01

Vertical track irregularities over viaducts in high-speed rail systems could be possibly caused by concrete creep if pre-stressed concrete bridges are used. For bridge spans that are almost uniformly distributed, track irregularity exhibits a near-regular wave profile that excites car bodies as a high-speed train moves over the bridge system. A long-wavelength irregularity induces low-frequency excitation that may be close to the natural frequencies of the train suspension system, thereby causing significant vibration of the car body. This paper investigates the relationship between the levels of car vibration, bridge vibration, track irregularity, and the train speed. First, this study investigates the vibration levels of a high-speed train and bridge system using 3D finite-element (FE) transient dynamic analysis, before and after adjustment of vertical track irregularities by means of installing shimming plates under rail pads. The analysis models are validated by in situ measurements and on-board measurement. Parametric studies of car body vibration and bridge vibration under three different levels of track irregularity at five train speeds and over two bridge span lengths are conducted using the FE model. Finally, a discontinuous shimming pattern is proposed to avoid vehicle suspension resonance.

Synchronizing data from irregularly sampled sensors

Science.gov (United States)

Uluyol, Onder

2017-07-11

A system and method include receiving a set of sampled measurements for each of multiple sensors, wherein the sampled measurements are at irregular intervals or different rates, re-sampling the sampled measurements of each of the multiple sensors at a higher rate than one of the sensor's set of sampled measurements, and synchronizing the sampled measurements of each of the multiple sensors.

A Bandwidth-Optimized Multi-Core Architecture for Irregular Applications

Energy Technology Data Exchange (ETDEWEB)

Secchi, Simone; Tumeo, Antonino; Villa, Oreste

2012-05-31

This paper presents an architecture template for next-generation high performance computing systems specifically targeted to irregular applications. We start our work by considering that future generation interconnection and memory bandwidth full-system numbers are expected to grow by a factor of 10. In order to keep up with such a communication capacity, while still resorting to fine-grained multithreading as the main way to tolerate unpredictable memory access latencies of irregular applications, we show how overall performance scaling can benefit from the multi-core paradigm. At the same time, we also show how such an architecture template must be coupled with specific techniques in order to optimize bandwidth utilization and achieve the maximum scalability. We propose a technique based on memory references aggregation, together with the related hardware implementation, as one of such optimization techniques. We explore the proposed architecture template by focusing on the Cray XMT architecture and, using a dedicated simulation infrastructure, validate the performance of our template with two typical irregular applications. Our experimental results prove the benefits provided by both the multi-core approach and the bandwidth optimization reference aggregation technique.

Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade

Science.gov (United States)

Balden, M.; Endstrasser, N.; Humrickhouse, P. W.; Rohde, V.; Rasinski, M.; von Toussaint, U.; Elgeti, S.; Neu, R.; the ASDEX Upgrade Team

2014-07-01

The dust collection and analysis strategy in ASDEX Upgrade (AUG) is described. During five consecutive operation campaigns (2007-2011), Si collectors were installed, which were supported by filtered vacuum sampling and collection with adhesive tapes in 2009. The outer and inner morphology (e.g. shape) and elemental composition of the collected particles were analysed by scanning electron microscopy. The majority of the ˜50 000 analysed particles on the Si collectors of campaign 2009 contain tungsten—the plasma-facing material in AUG—and show basically two different types of outer appearance: spheroids and irregularly shaped particles. By far most of the W-dominated spheroids consist of a solid W core, i.e. solidified W droplets. A part of these particles is coated with a low-Z material; a process that seems to happen presumably in the far scrape-off layer plasma. In addition, some conglomerates of B, C and W appear as spherical particles after their contact with plasma. By far most of the particles classified as B-, C- and W-dominated irregularly shaped particles consist of the same conglomerate with varying fraction of embedded W in the B-C matrix and some porosity, which can exceed 50%. The fragile structures of many conglomerates confirm the absence of intensive plasma contact. Both the ablation and mobilization of conglomerate material and the production of W droplets are proposed to be triggered by arcing. The size distribution of each dust particle class is best described by a log-normal distribution allowing an extrapolation of the dust volume and surface area. The maximum in this distribution is observed above the resolution limit of 0.28 µm only for the W-dominated spheroids, at around 1 µm. The amount of W-containing dust is extrapolated to be less than 300 mg on the horizontal areas of AUG.

Collection strategy, inner morphology, and size distribution of dust particles in ASDEX Upgrade

International Nuclear Information System (INIS)

Balden, M.; Endstrasser, N.; Rohde, V.; Rasinski, M.; Von Toussaint, U.; Elgeti, S.; Neu, R.; Humrickhouse, P.W.

2014-01-01

The dust collection and analysis strategy in ASDEX Upgrade (AUG) is described. During five consecutive operation campaigns (2007–2011), Si collectors were installed, which were supported by filtered vacuum sampling and collection with adhesive tapes in 2009. The outer and inner morphology (e.g. shape) and elemental composition of the collected particles were analysed by scanning electron microscopy. The majority of the ∼50 000 analysed particles on the Si collectors of campaign 2009 contain tungsten—the plasma-facing material in AUG—and show basically two different types of outer appearance: spheroids and irregularly shaped particles. By far most of the W-dominated spheroids consist of a solid W core, i.e. solidified W droplets. A part of these particles is coated with a low-Z material; a process that seems to happen presumably in the far scrape-off layer plasma. In addition, some conglomerates of B, C and W appear as spherical particles after their contact with plasma. By far most of the particles classified as B-, C- and W-dominated irregularly shaped particles consist of the same conglomerate with varying fraction of embedded W in the B–C matrix and some porosity, which can exceed 50%. The fragile structures of many conglomerates confirm the absence of intensive plasma contact. Both the ablation and mobilization of conglomerate material and the production of W droplets are proposed to be triggered by arcing. The size distribution of each dust particle class is best described by a log-normal distribution allowing an extrapolation of the dust volume and surface area. The maximum in this distribution is observed above the resolution limit of 0.28 µm only for the W-dominated spheroids, at around 1 µm. The amount of W-containing dust is extrapolated to be less than 300 mg on the horizontal areas of AUG. (paper)

Uniform irradiation of irregularly shaped cavities for photodynamic therapy.

Science.gov (United States)

Rem, A I; van Gemert, M J; van der Meulen, F W; Gijsbers, G H; Beek, J F

1997-03-01

It is difficult to achieve a uniform light distribution in irregularly shaped cavities. We have conducted a study on the use of hollow 'integrating' moulds for more uniform light delivery of photodynamic therapy in irregularly shaped cavities such as the oral cavity. Simple geometries such as a cubical box, a sphere, a cylinder and a 'bottle-neck' geometry have been investigated experimentally and the results have been compared with computed light distributions obtained using the 'radiosity method'. A high reflection coefficient of the mould and the best uniform direct irradiance possible on the inside of the mould were found to be important determinants for achieving a uniform light distribution.

Post-midnight equatorial irregularity distributions and vertical drift velocity variations during solstices

Science.gov (United States)

Su, S.-Y.; Liu, C. H.; Chao, C.-K.

2018-04-01

Longitudinal distributions of post-midnight equatorial ionospheric irregularity occurrences observed by ROCSAT-1 (1st satellite of the Republic of China) during moderate to high solar activity years in two solstices are studied with respect to the vertical drift velocity and density variations. The post-midnight irregularity distributions are found to be similar to the well-documented pre-midnight ones, but are different from some published distributions taken during solar minimum years. Even though the post-midnight ionosphere is sinking in general, longitudes of frequent positive vertical drift and high density seems to coincide with the longitudes of high irregularity occurrences. Large scatters found in the vertical drift velocity and density around the dip equator in different ROCSAT-1 orbits indicate the existence of large and frequent variations in the vertical drift velocity and density that seem to be able to provide sufficient perturbations for the Rayleigh-Taylor (RT) instability to cause the irregularity occurrences. The need of seeding agents such as gravity waves from atmospheric convective clouds to initiate the Rayleigh-Taylor instability may not be necessary.

Breaking Down Anonymity: Digital surveillance on irregular migrants in Germany and the Netherlands

NARCIS (Netherlands)

D.W.J. Broeders (Dennis)

2009-01-01

textabstractThe presence of irregular migrants causes a tough problem for policy makers. Political and popular aversion against the presence of irregular migrants has mounted in most West-European societies for years, yet their presence remains. Their exact numbers are obviously unknown - only

Simultaneous radar and spaced receiver VHF scintillation observations of ESF irregularities

Directory of Open Access Journals (Sweden)

D. Tiwari

2006-07-01

Full Text Available Simultaneous observations of equatorial spread F (ESF irregularities made on 10 nights during March-April 1998 and 1999, using an 18-MHz radar at Trivandrum (77° E, 8.5° N, dip 0.5° N and two spaced receivers recording scintillations on a 251-MHz signal at Tirunelveli (77.8° E, 8.7° N, dip 0.4° N, have been used to study the evolution of Equatorial Spread F (ESF irregularities. Case studies have been carried out on the day-to-day variability in ESF structure and dynamics, as observed by 18-MHz radar, and with spaced receiver measurements of average zonal drift Vo of the 251-MHz radio wave diffraction pattern on the ground, random velocity Vc, which is a measure of random changes in the characteristics of scintillation-producing irregularities, and maximum cross-correlation CI of the spaced receivers signals. Results show that in the initial phase of plasma bubble development, the greater the maximum height of ESF irregularities responsible for the radar backscatter, the greater the decorrelation is of the spaced receiver scintillation signals, indicating greater turbulence. The relationship of the maximum spectral width derived from the radar observations and CI also supports this result.

[Artificial cycle therapy of acupuncture and moxibustion for irregular menstruation].

Science.gov (United States)

Wu, Jie; Yang, Lijie; Chen, Yajie; Li, Qing; Chen, Lin

2015-03-01

Through the discussion on TCM physiological characters of females in follicular, ovulatory, luteal and menstrual phases and treatment principles, the clinical application of artificial cycle therapy of acupuncture and moxibustion was introduced for irregular menstruation and the typical cases were attached. It is suggested that the menstrual cycle follows the growth-consumption rule of yin, yang, qi and blood. The corresponding treatment principles should be applied in accordance with the change rule of menstrual cycle. Hence, it is worth to adopt the artificial cycle therapy of acupuncture and moxibustion for irregular menstruation in clinical application.

Properties of the Irregular Satellite System around Uranus Inferred from K2, Herschel, and Spitzer Observations

Science.gov (United States)

Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Mommert, M.; Szakáts, R.; Müller, T.; Kiss, L. L.

2017-09-01

In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel/PACS and Spitzer/MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

Properties of the Irregular Satellite System around Uranus Inferred from K2 , Herschel , and Spitzer Observations

Energy Technology Data Exchange (ETDEWEB)

Farkas-Takács, A.; Kiss, Cs.; Pál, A.; Molnár, L.; Szabó, Gy. M.; Hanyecz, O.; Sárneczky, K.; Szabó, R.; Marton, G.; Szakáts, R.; Kiss, L. L. [Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences, Konkoly Thege Miklós út 15-17, H-1121 Budapest (Hungary); Mommert, M. [Department of Physics and Astronomy, Northern Arizona University, P.O. Box 6010, Flagstaff, AZ 86011 (United States); Müller, T., E-mail: farkas.aniko@csfk.mta.hu [Max-Plank-Institut für extraterrestrsiche Pyhsik, Garching (Germany)

2017-09-01

In this paper, we present visible-range light curves of the irregular Uranian satellites Sycorax, Caliban, Prospero, Ferdinand, and Setebos taken with the Kepler Space Telescope over the course of the K2 mission. Thermal emission measurements obtained with the Herschel /PACS and Spitzer /MIPS instruments of Sycorax and Caliban were also analyzed and used to determine size, albedo, and surface characteristics of these bodies. We compare these properties with the rotational and surface characteristics of irregular satellites in other giant planet systems and also with those of main belt and Trojan asteroids and trans-Neptunian objects. Our results indicate that the Uranian irregular satellite system likely went through a more intense collisional evolution than the irregular satellites of Jupiter and Saturn. Surface characteristics of Uranian irregular satellites seem to resemble the Centaurs and trans-Neptunian objects more than irregular satellites around other giant planets, suggesting the existence of a compositional discontinuity in the young solar system inside the orbit of Uranus.

On the total irregularity strength of caterpillar with each internal vertex has degree three

Science.gov (United States)

Indriati, Diari; Rosyida, Isnaini; Widodo

2018-04-01

Let G be a simple, connected and undirected graph with vertex set V and edge set E. A total k-labeling f:V \\cup E\\to \\{1,2,\\ldots,k\\} is defined as totally irregular total k-labeling if the weights of any two different both vertices and edges are distinct. The weight of vertex x is defined as wt(x)=f(x)+{\\sum }xy\\in Ef(xy), while the weight of edge xy is wt(xy)=f(x)+f(xy)+f(y). A minimum k for which G has totally irregular total k-labeling is mentioned as total irregularity strength of G and denoted by ts(G). This paper contains investigation of totally irregular total k-labeling and determination of their total irregularity strengths for caterpillar graphs with each internal vertex between two stars has degree three. The results are ts({S}n,3,n)=\\lceil \\frac{2n}{2}\\rceil, ts({S}n,3,3,n)=\\lceil \\frac{2n+1}{2}\\rceil and ts({S}n,3,3,3,n)=\\lceil \\frac{2n+2}{2}\\rceil for n > 4:

Optical trapping and manipulation of Mie particles with Airy beam

International Nuclear Information System (INIS)

Zhao, Ziyu; Zang, Weiping; Tian, Jianguo

2016-01-01

In this paper we calculate the radiation forces and moving trajectories of Mie particles induced by 1D Airy beams using the plane wave spectrum method and arbitrary beam theory. Numerical results show that both the transverse and the longitudinal radiation forces are deeply dependent on the relative refractive index, radii and positions of the scattering particles illuminated by the Airy beam. Due to the radiation forces, Mie particles with different radii and initial positions can be dragged into the nearest main intensity lobes, and move along parabolic trajectories in the direction of the Poynting vector. At the ends of these trajectories, in the presence of Brownian force, the trapped scattering particles show irregular Brownian movement near their equilibrium positions. This characteristic property of Airy beams enables optical sorting to be used more easily in the colloidal and biological sciences. (paper)

The effect of earthquake on architecture geometry with non-parallel system irregularity configuration

Science.gov (United States)

Teddy, Livian; Hardiman, Gagoek; Nuroji; Tudjono, Sri

2017-12-01

Indonesia is an area prone to earthquake that may cause casualties and damage to buildings. The fatalities or the injured are not largely caused by the earthquake, but by building collapse. The collapse of the building is resulted from the building behaviour against the earthquake, and it depends on many factors, such as architectural design, geometry configuration of structural elements in horizontal and vertical plans, earthquake zone, geographical location (distance to earthquake center), soil type, material quality, and construction quality. One of the geometry configurations that may lead to the collapse of the building is irregular configuration of non-parallel system. In accordance with FEMA-451B, irregular configuration in non-parallel system is defined to have existed if the vertical lateral force-retaining elements are neither parallel nor symmetric with main orthogonal axes of the earthquake-retaining axis system. Such configuration may lead to torque, diagonal translation and local damage to buildings. It does not mean that non-parallel irregular configuration should not be formed on architectural design; however the designer must know the consequence of earthquake behaviour against buildings with irregular configuration of non-parallel system. The present research has the objective to identify earthquake behaviour in architectural geometry with irregular configuration of non-parallel system. The present research was quantitative with simulation experimental method. It consisted of 5 models, where architectural data and model structure data were inputted and analyzed using the software SAP2000 in order to find out its performance, and ETAB2015 to determine the eccentricity occurred. The output of the software analysis was tabulated, graphed, compared and analyzed with relevant theories. For areas of strong earthquake zones, avoid designing buildings which wholly form irregular configuration of non-parallel system. If it is inevitable to design a

Synthesis, multi-nonlinear dielectric resonance and electromagnetic absorption properties of hcp-cobalt particles

International Nuclear Information System (INIS)

Wen, Shulai; Liu, Ying; Zhao, Xiuchen; Cheng, Jingwei; Li, Hong

2014-01-01

Hcp-cobalt particles were successfully prepared by a liquid phase reduction method, and the microstructure, static magnetic properties, electromagnetic and microwave absorption properties of the cobalt particles with irregular shape were investigated in detail. The measured results indicate that the saturation magnetization was less than that of hcp-Co single crystals, and the coercivity was larger than that of bulk cobalt crystal. The permittivity presents multi-nonlinear dielectric resonance, which may result from the irregular shape containing parts of cutting angle of dodecahedron of cobalt particles. The real part of permeability decreases with the frequency, and the imaginary part has a wide resonant peak. The paraffin-based composite containing 70 wt% cobalt particles possessed strong absorption characteristics with a minimum RL of −38.97 dB at 10.81 GHz and an absorption band with RL under −10 dB from 8.72 to 13.26 GHz when the thickness is 1.8 mm, which exhibits excellent microwave absorption in middle and high frequency. The architectural design of material morphologies is important for improving microwave absorption properties toward future application. - Highlights: • Hcp-cobalt particles were prepared by a liquid phase reduction method. • The saturation magnetization was less than that of hcp-Co single crystals. • The permittivity presents multi-nonlinear dielectric resonance. • The real part of permeability decreases with frequency, and the imaginary part presents a wide resonant peak. • The paraffin-based composite possessed a minimum RL of −38.97 dB at 10.81 GHz

Evaluation of irregular menses in perimenarcheal girls: a pilot study.

Science.gov (United States)

Browner-Elhanan, Karen J; Epstein, Jonathan; Alderman, Elizabeth M

2003-12-01

Acyclic vaginal bleeding in girls within three years of menarche is most commonly attributed to an immature hypothalamic-pituitary-ovarian axis. Assuming this diagnosis may preclude the practitioner from performing more definitive studies and thereby diagnosing other, treatable causes of menstrual irregularities. A retrospective chart review of 178 girls presenting to an inner-city hospital-based adolescent clinic within three years of menarche was performed. Personal and family medical and menarcheal history was assessed, and findings on physical and laboratory examination performed were evaluated. Of the 178 girls still perimenarcheal at presentation, 47 were the focus of this study. Of these, 39 had no significant findings on physical examination, while 3 had signs of functional ovarian hyperandrogenism (FOH) including obesity, hirsutism, and moderate acne with corresponding LH/FSH ratios>3, although pelvic ultrasound examination revealed normal ovaries. Four of the 39 patients with normal physical exams had LH/FSH testing done, and 1 of the 4 had an abnormal LH/FSH ratio, indicating possible FOH. Two of the 47 patients were pregnant. Other laboratory abnormalities included microcytic, hypochromic anemia in patients, and an elevated Erythrocyte Sedimentation Rate in a patient later diagnosed with a rheumatologic disorder. Those perimenarcheal girls presenting with irregular menses and findings including obesity, acne, or pallor, were likely to have treatable causes of menstrual irregularities. In one of the four girls with a normal physical examination, hormonal testing indicated possible FOH, thus suggesting that hormonal evaluation of perimenarcheal girls with menstrual irregularities may be justified, as it may reveal previously unsuspected pathology.

Irregular Warfare: Impact on Future Professional Military Education

National Research Council Canada - National Science Library

Paschal, David G

2006-01-01

... to operate effectively in an irregular warfare environment. The utility of a decisive war between nation states continues to decline and will eventually reach critical mass based upon the extreme imbalance of military power and a U.S. monopoly...

Research on making reactor buildings of irregular plan and elevation forms aseismatic

International Nuclear Information System (INIS)

Okawa, Izuru; Yamauchi, Yasuyuki

1997-01-01

The necessity of pursuing the possibility of irregular form buildings as the condition of location for construction is limited, and the rational and economical arrangement of equipment and piping is considered. In order to know the effect that irregular forms exert to the aseismatic ability of buildings, it is indispensable to develop the program for precision three-dimensional elastoplastic analysis at the time of earthquakes. As the means of solving the problem, the introduction of seismic insulation structure is conceivable. The investigation of seismic insulator and its modeling and the analysis of earthquake response were carried out, and the irregular form and the effect of seismic insulation were investigated, and the results of vibration test using test specimens were summarized. The concrete items of investigation were the characteristics of input earthquake motion, the techniques of analysis, the parametric study taking the input and various characteristics of buildings in consideration, and the synthetic assessment. The vibration table experiment and the static loading experiment for the purpose of grasping the response behavior in the case of irregular form of wall type and seismic insulation type structures were carried out, and the results are reported. (K.I.)

Irregular analytical errors in diagnostic testing - a novel concept.

Science.gov (United States)

Vogeser, Michael; Seger, Christoph

2018-02-23

In laboratory medicine, routine periodic analyses for internal and external quality control measurements interpreted by statistical methods are mandatory for batch clearance. Data analysis of these process-oriented measurements allows for insight into random analytical variation and systematic calibration bias over time. However, in such a setting, any individual sample is not under individual quality control. The quality control measurements act only at the batch level. Quantitative or qualitative data derived for many effects and interferences associated with an individual diagnostic sample can compromise any analyte. It is obvious that a process for a quality-control-sample-based approach of quality assurance is not sensitive to such errors. To address the potential causes and nature of such analytical interference in individual samples more systematically, we suggest the introduction of a new term called the irregular (individual) analytical error. Practically, this term can be applied in any analytical assay that is traceable to a reference measurement system. For an individual sample an irregular analytical error is defined as an inaccuracy (which is the deviation from a reference measurement procedure result) of a test result that is so high it cannot be explained by measurement uncertainty of the utilized routine assay operating within the accepted limitations of the associated process quality control measurements. The deviation can be defined as the linear combination of the process measurement uncertainty and the method bias for the reference measurement system. Such errors should be coined irregular analytical errors of the individual sample. The measurement result is compromised either by an irregular effect associated with the individual composition (matrix) of the sample or an individual single sample associated processing error in the analytical process. Currently, the availability of reference measurement procedures is still highly limited, but LC

Rocket observation of electron density irregularities in the lower E region

International Nuclear Information System (INIS)

Watanabe, Yuzo; Nakamura, Yoshiharu; Amemiya, Hiroshi.

1990-01-01

Local ionospheric electron density irregularities in the scale size of 3 m to 300 m have been measured on the ascending path from 74 km to 93 km by a fix biased Langmuir probe on board the S-310-16 sounding rocket. The rocket was launched at 22:40:00 on February 1, 1986 from Kagoshima Space Center in Japan. It is found from frequency analysis of the data that the spectral index of the irregularities is 0.9 to 1.8 and the irregularity amplitude is 1 to 15 %. The altitude where the amplitude reaches its maximum is 88 km. The generation mechanism of these irregularities is explained by the neutral turbulence theory, which indicates that the spectral index is 5/3 and has been confirmed by a chemical release experiment using rockets over India to be valid up to about 110 km. From frequency analysis of the data observed during the descent in the lower E region, we have found that the rocket-wake effect becomes larger when the probe is situated near the edge of the rocket-wake, and that this is also the case even when the rocket-wake effect does not clearly appear in the DC current signal which approximately changes in proportion to the electron density, where the probe is completely situated inside the rocket-wake region. (author)

The effect of concentration of glycerol and electric current on the morphology and particle size of electrodeposited cadmium powder

Directory of Open Access Journals (Sweden)

S. G. Viswanath

2013-06-01

Full Text Available Cadmium powder was obtained by electrodeposition of cadmium from glycerol and sulphuric acid. The morphology and particle size of these powders were studied. Broken dendrites, intermingled with spongy and irregular particles were observed in the powder. Around 60% of particles were below 100 µm. XRD studies showed that particles with sizes between 212.2 and 303.2 nm were present in the powder. The apparent density of cadmium powder decreased with increase in concentration of glycerol. The stability of the powder and current efficiency were also studied

The dynamics of rings around small, irregular bodies

Science.gov (United States)

Sicardy, Bruno

2017-06-01

Stellar occultations revealed the presence of two dense rings around the Centaur object (10199) Chariklo (Braga-Ribas et al., Nature 508, 72, 2014). This is the first ring system discovered around an object that is not a giant planet, suggesting that rings may exist around numerous bodies in the solar system. Chariklo's rings roughly reside at the outer limit of the Roche zone of the body. Moreover, the main ring has sharp edges, which call for the presence of putative shepherd satellites. Those characteristics give an image of Chariklo's rings that are rather similar, in terms of dynamics, to those surrounding the gaseous planets.An important difference exists, however, between giant planets and small bodies: the formers are highly axisymmetric, while the latters can support mass anomalies (eg surface topographic features) or non-spherical shapes (eg an ellipsoidal figure of equilibrium) that involve masses, relative to the body itself, as large as 10-4-10-3.We investigate the effect of non-axisymmetric terms in the potential of the body upon a collisional debris disk that initially surrounds a small irregular body. We show that the corotation points being maxima of energy, dissipative collisions remove the particles from the corotation zone over short time scales (< 106 years). Moreover, the Lindblad resonances inside the corotation radius create torques that drive the particles onto the surface of the central body. Conversely, the outer Lindblad resonances push the disk material beyond the outer 3/2 and 2/1 Lindblad resonances.Taking as an example Chariklo's ring system, for which recent data have been obtained from stellar occultations, we show that the Lindblad resonant torques actuate over short time scales (< 106 years). This general picture offers a natural explanation of the presence of dense rings at the outer limit of Chariklo's Roche zone, and their absence closer to the body.The work leading to this results has received funding from the European

Constructing irregular surfaces to enclose macromolecular complexes for mesoscale modeling using the discrete surface charge optimization (DISCO) algorithm.

Science.gov (United States)

Zhang, Qing; Beard, Daniel A; Schlick, Tamar

2003-12-01

Salt-mediated electrostatics interactions play an essential role in biomolecular structures and dynamics. Because macromolecular systems modeled at atomic resolution contain thousands of solute atoms, the electrostatic computations constitute an expensive part of the force and energy calculations. Implicit solvent models are one way to simplify the model and associated calculations, but they are generally used in combination with standard atomic models for the solute. To approximate electrostatics interactions in models on the polymer level (e.g., supercoiled DNA) that are simulated over long times (e.g., milliseconds) using Brownian dynamics, Beard and Schlick have developed the DiSCO (Discrete Surface Charge Optimization) algorithm. DiSCO represents a macromolecular complex by a few hundred discrete charges on a surface enclosing the system modeled by the Debye-Hückel (screened Coulombic) approximation to the Poisson-Boltzmann equation, and treats the salt solution as continuum solvation. DiSCO can represent the nucleosome core particle (>12,000 atoms), for example, by 353 discrete surface charges distributed on the surfaces of a large disk for the nucleosome core particle and a slender cylinder for the histone tail; the charges are optimized with respect to the Poisson-Boltzmann solution for the electric field, yielding a approximately 5.5% residual. Because regular surfaces enclosing macromolecules are not sufficiently general and may be suboptimal for certain systems, we develop a general method to construct irregular models tailored to the geometry of macromolecules. We also compare charge optimization based on both the electric field and electrostatic potential refinement. Results indicate that irregular surfaces can lead to a more accurate approximation (lower residuals), and the refinement in terms of the electric field is more robust. We also show that surface smoothing for irregular models is important, that the charge optimization (by the TNPACK

Irregular Polyomino-Shaped Subarrays for Space-Based Active Arrays

Directory of Open Access Journals (Sweden)

R. J. Mailloux

2009-01-01

Full Text Available This paper presents new results showing the application of polyomino-based subarrays to limited field of view and wideband, wide-angle scanning. This technology can reduce the number of phase controls in arrays used for limited sector coverage or the number of time delay devices for wideband radar or communications, and so can reduce the cost of space-based active arrays. We concentrate on the wideband application. Results are presented by comparing the gain and peak sidelobe results of irregular polyomino subarray-based arrays with those of rectangular subarrays. It is shown that using irregular polyomino subarrays can result in a major decrease in sidelobes while presenting, in most cases, only a few tenths of a dB gain reduction compared to rectangular subarrays.

Third-order theory for multi-directional irregular waves

DEFF Research Database (Denmark)

Madsen, Per A.; Fuhrman, David R.

2012-01-01

A new third-order solution for multi-directional irregular water waves in finite water depth is presented. The solution includes explicit expressions for the surface elevation, the amplitude dispersion and the vertical variation of the velocity potential. Expressions for the velocity potential at...

Measuring Mass-Based Hygroscopicity of Atmospheric Particles through in situ Imaging

Energy Technology Data Exchange (ETDEWEB)

Piens, Dominique` Y.; Kelly, Stephen T.; Harder, Tristan; Petters, Markus D.; O' Brien, Rachel; Wang, Bingbing; Teske, Ken; Dowell, Pat; Laskin, Alexander; Gilles, Mary K.

2016-04-18

Quantifying how atmospheric particles interact with water vapor is critical for understanding the effects of aerosols on climate. We present a novel method to measure the mass-based hygroscopicity of particles while characterizing their elemental and carbon functional group compositions. Since mass-based hygroscopicity is insensitive to particle geometry, it is advantageous for probing the hygroscopic behavior of atmospheric particles, which can have irregular morphologies. Combining scanning electron microscopy with energy dispersive X-ray analysis (SEM/EDX), scanning transmission X-ray microscopy (STXM) analysis, and in situ STXM humidification experiments, this method was validated using laboratory-generated, atmospherically relevant particles. Then, the hygroscopicity and elemental composition of 15 complex atmospheric particles were analyzed by leveraging quantification of C, N, and O from STXM, and complementary elemental quantification from SEM/EDX. We found three types of hygroscopic responses, and correlated high hygroscopicity with Na and Cl content. The mixing state determined for 158 particles broadly agreed with those of the humidified particles, indicating the potential to infer the atmospheric hygroscopic behavior from a selected subset of particles. These methods offer unique quantitative capabilities to characterize and correlate the hygroscopicity and chemistry of individual submicron atmospheric particles.

Some new features of electron density irregularities over SHAR during strong spread F

Directory of Open Access Journals (Sweden)

S. Raizada

Full Text Available An RH-560 rocket flight was conducted from Sriharikota rocket range (SHAR (14°N, 80°E, dip latitude 5.5°N to study electron density and electric field irregularities during spread F. The rocket was launched at 2130 local time (LT and it attained an apogee of 348 km. Results of electron density fluctuations are presented here. Two extremely sharp layers of very high electron density were observed at 105 and 130 km. The electron density increase in these layers was by a factor of 50 in a vertical extent of 10 km. Large depletions in electron density were observed around 175 and 238 km. Both sharp layers as well as depletions were observed also during the descent. The presence of sharp layers and depletions during the ascent and the descent of the rocket as well as an order of magnitude less electron density, in 150-300 km region during the descent, indicate the presence of strong large-scale horizontal gradients in the electron density. Some of the valley region irregularities (165-178 km, in the intermediate scale size range, observed during this flight, show spectral peaks at 2 km and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of new type. The growth rate of intermediate scale size irregularities, produced through generalized Rayleigh Taylor instability, was calculated for the 200-330 km altitude, using observed values of electron density gradients and an assumed vertically downward wind of 20 ms^-1. These growth rate calculations suggest that the observed irregularities could be produced by the gradient drift instability.

Key words: Ionosphere (equatorial ionosphere; ionospheric irregularities - Radio science (ionospheric physics

Some new features of electron density irregularities over SHAR during strong spread F

Directory of Open Access Journals (Sweden)

S. Raizada

2000-02-01

Full Text Available An RH-560 rocket flight was conducted from Sriharikota rocket range (SHAR (14°N, 80°E, dip latitude 5.5°N to study electron density and electric field irregularities during spread F. The rocket was launched at 2130 local time (LT and it attained an apogee of 348 km. Results of electron density fluctuations are presented here. Two extremely sharp layers of very high electron density were observed at 105 and 130 km. The electron density increase in these layers was by a factor of 50 in a vertical extent of 10 km. Large depletions in electron density were observed around 175 and 238 km. Both sharp layers as well as depletions were observed also during the descent. The presence of sharp layers and depletions during the ascent and the descent of the rocket as well as an order of magnitude less electron density, in 150-300 km region during the descent, indicate the presence of strong large-scale horizontal gradients in the electron density. Some of the valley region irregularities (165-178 km, in the intermediate scale size range, observed during this flight, show spectral peaks at 2 km and can be interpreted in terms of the image striation theory suggested by Vickrey et al. The irregularities at 176 km do not exhibit any peak at kilometer scales and appear to be of new type. The growth rate of intermediate scale size irregularities, produced through generalized Rayleigh Taylor instability, was calculated for the 200-330 km altitude, using observed values of electron density gradients and an assumed vertically downward wind of 20 ms-1. These growth rate calculations suggest that the observed irregularities could be produced by the gradient drift instability.Key words: Ionosphere (equatorial ionosphere; ionospheric irregularities - Radio science (ionospheric physics

Charged particle flux near the Mars

International Nuclear Information System (INIS)

Vernov, S.N.; Tverskoj, B.A.; Yakovlev, V.A.

1974-01-01

The data on cosmic ray fluxes, obtained for the first time in the areocentric orbit by means of the 'Mars-2' satellite are given and discussed. The measurements were carried out on the variable solar cosmic ray flux background from December 14, 1971, to June 1, 1972. For this reason it is difficult to strictly separate local increases in the soft particle fluxes near the planet (electrons with Esub(e)>0.1 and 0.3MeV and protons with Esub(p)>1 and 5MeV) from the variation of corresponding particles of a solar origin. The detected intensities exceed the background which is caused by detection of particles of a galactic origin even at the complete overlap of the counter aperture by the planet. The possible causes of the detected irregularities in an intensity are discussed. It has been established definitely that neither Mars nor Venus have radiation belts at an election energy of Esub(e)>100KeV and proton energy of Esup(p)>1

The Relationships among Cognitive Correlates and Irregular Word, Non-Word, and Word Reading

Science.gov (United States)

Abu-Hamour, Bashir; University, Mu'tah; Urso, Annmarie; Mather, Nancy

2012-01-01

This study explored four hypotheses: (a) the relationships among rapid automatized naming (RAN) and processing speed (PS) to irregular word, non-word, and word reading; (b) the predictive power of various RAN and PS measures, (c) the cognitive correlates that best predicted irregular word, non-word, and word reading, and (d) reading performance of…

SUB-SAHARAN IRREGULAR MIGRANTS IN MOROCCO & THE EXCEPTIONAL REGULARISATION PROGRAMME IN 2014

OpenAIRE

Naama, Mbarek

2017-01-01

Naama, Mbarek. Sub-Saharan Irregular Migrants in Morocco and the Exceptional Regularisation Programme in 2014. Diak South Helsinki Finland. Spring 2017. 43 Pages. Language: English. Diaconia University of Applied Sciences, Degree Programme in Social Services, Option in Community Development, Bachelor of Social Services (UAS). After decades of ignoring irregular migration and refusing to acknowledge that Morocco is no longer just a transit but also a host country for increasing complex mig...

Gait Characteristics Associated with Trip-Induced Falls on Level and Sloped Irregular Surfaces

Directory of Open Access Journals (Sweden)

Andrew Merryweather

2011-11-01

Full Text Available Same level falls continue to contribute to an alarming number of slip/trip/fall injuries in the mining workforce. The objective of this study was to investigate how walking on different surface types and transverse slopes influences gait parameters that may be associated with a trip event. Gait analysis was performed for ten subjects on two orientations (level and sloped on smooth, hard surface (control and irregular (gravel, larger rocks surfaces. Walking on irregular surfaces significantly increased toe clearance compared to walking on the smooth surface. There was a significant (p < 0.05 decrease in cadence (steps/min, stride length (m, and speed (m/s from control to gravel to larger rocks. Significant changes in external rotation and increased knee flexion while walking on irregular surfaces were observed. Toe and heel clearance requirements increased on irregular surfaces, which may provide an explanation for trip-induced falls; however, the gait alterations observed in the experienced workers used as subjects would likely improve stability and recovery from a trip.

Geomagnetic storm effects on the occurrences of ionospheric irregularities over the African equatorial/low-latitude region

Science.gov (United States)

Amaechi, P. O.; Oyeyemi, E. O.; Akala, A. O.

2018-04-01

The study investigated the effects of intense geomagnetic storms of 2015 on the occurrences of large scale ionospheric irregularities over the African equatorial/low-latitude region. Four major/intense geomagnetic storms of 2015 were analyzed for this study. These storms occurred on 17th March 2015 (-229 nT), 22nd June 2015 (-204 nT), 7th October 2015 (-124 nT), and 20th December 2015 (-170 nT). Total Electron Content (TEC) data obtained from five African Global Navigation Satellite Systems (GNSS) stations, grouped into eastern and western sectors were used to derive the ionospheric irregularities proxy indices, e.g., rate of change of TEC (ROT), ROT index (ROTI) and ROTI daily average (ROTIAVE). These indices were characterized alongside with the disturbance storm time (Dst), the Y component of the Interplanetary Electric Field (IEFy), polar cap (PC) index and the H component of the Earth's magnetic field from ground-based magnetometers. Irregularities manifested in the form of fluctuations in TEC. Prompt penetration of electric field (PPEF) and disturbance dynamo electric field (DDEF) modulated the behaviour of irregularities during the main and recovery phases of the geomagnetic storms. The effect of electric field over both sectors depends on the local time of southward turning of IMF Bz. Consequently, westward electric field inhibited irregularities during the main phase of March and October 2015 geomagnetic storms, while for the June 2015 storm, eastward electric field triggered weak irregularities over the eastern sector. The effect of electric field on irregularities during December 2015 storm was insignificant. During the recovery phase of the storms, westward DDEF suppressed irregularities.

Irregular Warfare: Special Operations Joint Professional Military Education Transformation

National Research Council Canada - National Science Library

Cannady, Bryan H

2008-01-01

... on today's battlefront in Afghanistan and Iraq and in the Global War on Terrorism (GWOT). At the forefront of the GWOT and irregular warfare are the United States Special Operations Command (USSOCOM...

Creating and using a type of free-form geometry in Monte Carlo particle transport

International Nuclear Information System (INIS)

Wessol, D.E.; Wheeler, F.J.

1993-01-01

While the reactor physicists were fine-tuning the Monte Carlo paradigm for particle transport in regular geometries, the computer scientists were developing rendering algorithms to display extremely realistic renditions of irregular objects ranging from the ubiquitous teakettle to dynamic Jell-O. Even though the modeling methods share a common basis, the initial strategies each discipline developed for variance reduction were remarkably different. Initially, the reactor physicist used Russian roulette, importance sampling, particle splitting, and rejection techniques. In the early stages of development, the computer scientist relied primarily on rejection techniques, including a very elegant hierarchical construction and sampling method. This sampling method allowed the computer scientist to viably track particles through irregular geometries in three-dimensional space, while the initial methods developed by the reactor physicists would only allow for efficient searches through analytical surfaces or objects. As time goes by, it appears there has been some merging of the variance reduction strategies between the two disciplines. This is an early (possibly first) incorporation of geometric hierarchical construction and sampling into the reactor physicists' Monte Carlo transport model that permits efficient tracking through nonuniform rational B-spline surfaces in three-dimensional space. After some discussion, the results from this model are compared with experiments and the model employing implicit (analytical) geometric representation

The regularized monotonicity method: detecting irregular indefinite inclusions

DEFF Research Database (Denmark)

Garde, Henrik; Staboulis, Stratos

2018-01-01

inclusions, where the conductivity distribution has both more and less conductive parts relative to the background conductivity; one such method is the monotonicity method of Harrach, Seo, and Ullrich. We formulate the method for irregular indefinite inclusions, meaning that we make no regularity assumptions...

Convection-diffusion lattice Boltzmann scheme for irregular lattices

NARCIS (Netherlands)

Sman, van der R.G.M.; Ernst, M.H.

2000-01-01

In this paper, a lattice Boltzmann (LB) scheme for convection diffusion on irregular lattices is presented, which is free of any interpolation or coarse graining step. The scheme is derived using the axioma that the velocity moments of the equilibrium distribution equal those of the

Simultaneous radar and spaced receiver VHF scintillation observations of ESF irregularities

Directory of Open Access Journals (Sweden)

D. Tiwari

2006-07-01

Full Text Available Simultaneous observations of equatorial spread F (ESF irregularities made on 10 nights during March-April 1998 and 1999, using an 18-MHz radar at Trivandrum (77° E, 8.5° N, dip 0.5° N and two spaced receivers recording scintillations on a 251-MHz signal at Tirunelveli (77.8° E, 8.7° N, dip 0.4° N, have been used to study the evolution of Equatorial Spread F (ESF irregularities. Case studies have been carried out on the day-to-day variability in ESF structure and dynamics, as observed by 18-MHz radar, and with spaced receiver measurements of average zonal drift V_o of the 251-MHz radio wave diffraction pattern on the ground, random velocity V_c, which is a measure of random changes in the characteristics of scintillation-producing irregularities, and maximum cross-correlation C_I of the spaced receivers signals. Results show that in the initial phase of plasma bubble development, the greater the maximum height of ESF irregularities responsible for the radar backscatter, the greater the decorrelation is of the spaced receiver scintillation signals, indicating greater turbulence. The relationship of the maximum spectral width derived from the radar observations and C_I also supports this result.

The nature and source of irregular discharges to stormwater entering Sydney estuary, Australia

International Nuclear Information System (INIS)

Beck, H.J.; Birch, G.F.

2014-01-01

Irregular discharges of polluted stormwater into drainage systems during base flow (no rainfall) result in acute ecological impacts within fluvial and estuarine environments. In this study, metal and TSS concentrations were significantly more variable during business hours of weekdays (i.e. high-business activity) than weekends/public holidays (i.e. low-business activity) within three highly-urbanised catchments of Sydney estuary (Australia), as determined by analysing multivariate dispersion (PERMDISP). Concentrations of TSS and all metals analysed (Al, Ca, Cu, Fe, Mg, Pb and Zn) were also significantly greater during high- than low-business periods within at least one of the three catchments. In no case were concentrations significantly higher during low- than high-business periods. This pattern of contamination supports the hypothesis that commercial and industrial sources are major contributors of irregular discharges of contamination to Sydney estuary. Irregular discharges and consequential ecological impacts may be effectively reduced in this environment by focussing management efforts on these activities. - Highlights: • Irregular discharges of pollution have acute impacts on aquatic ecosystems. • These discharges were thought to be made during low activity periods, such as night. • Pollution was more concentrated and erratic during high- than low-business periods. • Timing of pollution suggests commercial and industrial activities are major sources. • Discharges effectively reduced by managing commercial and industrial activities. - Previously unreported irregular, illegal discharges of polluted stormwater released to estuaries result in acute ecological impacts and are potentially related to commercial/industrial activities

Characterization of the low latitude plasma density irregularities observed using C/NOFS and SCINDA data

Science.gov (United States)

Andima, Geoffrey; Amabayo, Emirant B.; Jurua, Edward; Cilliers, Pierre J.

2018-01-01

Complex electrodynamic processes over the low latitude region often result in post sunset plasma density irregularities which degrade satellite communication and navigation. In order to forecast the density irregularities, their occurrence time, duration and location need to be quantified. Data from the Communication/Navigation Outage Forecasting System (C/NOFS) satellite was used to characterize the low latitude ion density irregularities from 2011 to 2013. This was supported by ground based data from the SCIntillation Network Decision Aid (SCINDA) receivers at Makerere (Geographic coordinate 32.6°E, 0.3°N, and dip latitude -9.3°N) and Nairobi (Geographic coordinate 36.8°E, -1.3°N, and dip latitude -10.8°N). The results show that irregularities in ion density have a daily pattern with peaks from 20:00 to 24:00 Local Time (LT). Scintillation activity at L band and VHF over East Africa peaked in 2011 and 2012 from 20:00 to 24:00 LT, though in many cases scintillation at VHF persisted longer than that at L band. A longitudinal pattern in ion density irregularity occurrence was observed with peaks over 135-180°E and 270-300°E. The likelihood of ion density irregularity occurrence decreased with increasing altitude. Analysis of C/NOFS zonal ion drift velocities showed that the largest nighttime and daytime drifts were in 270-300°E and 300-330°E longitude regions respectively. Zonal irregularity drift velocities over East Africa were for the first time estimated from L-band scintillation indices. The results show that the velocity of plasma density irregularities in 2011 and 2012 varied daily, and hourly in the range of 50-150 m s-1. The zonal drift velocity estimates from the L-band scintillation indices had good positive correlation with the zonal drift velocities derived from VHF receivers by the spaced receiver technique.

Star formation histories of irregular galaxies

International Nuclear Information System (INIS)

Gallagher, J.S. III; Hunter, D.A.; Tutukov, A.V.

1984-01-01

We explore the star formation histories of a selection of irregular and spiral galaxies by using three parameters that sample the star formation rate (SFR) at different epochs: (1) the mass of a galaxy in the form of stars measures the SFR integrated over a galaxy's lifetime; (2) the blue luminosity is dominated primarily by stars formed over the past few billion years; and (3) Lyman continuum photon fluxes derived from Hα luminosities give the current ( 8 yr) SFR

Fractal and Morphological Characteristics of Single Marble Particle Crushing in Uniaxial Compression Tests

Directory of Open Access Journals (Sweden)

Yidong Wang

2015-01-01

Full Text Available Crushing of rock particles is a phenomenon commonly encountered in geotechnical engineering practice. It is however difficult to study the crushing of rock particles using classical theory because the physical structure of the particles is complex and irregular. This paper aims at evaluating fractal and morphological characteristics of single rock particle. A large number of particle crushing tests are conducted on single rock particle. The force-displacement curves and the particle size distributions (PSD of crushed particles are analysed based on particle crushing tests. Particle shape plays an important role in both the micro- and macroscale responses of a granular assembly. The PSD of an assortment of rocks are analysed by fractal methods, and the fractal dimension is obtained. A theoretical formula for particle crushing strength is derived, utilising the fractal model, and a simple method is proposed for predicting the probability of particle survival based on the Weibull statistics. Based on a few physical assumptions, simple equations are derived for determining particle crushing energy. The results of applying these equations are tested against the actual experimental data and prove to be very consistent. Fractal theory is therefore applicable for analysis of particle crushing.

Migración y violencia en Cancún: estudio de dos asentamientos irregulares; Migração e violencia em Cancún: estudo de dois assentamentos irregulares; Migration and violence in Cancún: study of two irregular settlements

Directory of Open Access Journals (Sweden)

Minerva Alavez San Pedro

2017-07-01

Full Text Available Resumen: El presente texto ofrece una aproximación a las condiciones actuales de violencia en dos asentamientos irregulares de Cancún, que se ubica en el estado de Quintana Roo, México, como consecuencia de la migración laboral que ha experimentado esta localidad desde su creación en 1970 como Centro Turístico Integral. Para elaborar este trabajo se realizó, además de la revisión bibliográfica, un seguimiento hemerográfico de medios de comunicación locales y nacionales y un trabajo etnográfico en las colonias El Milagro y Tres Reyes de abril de 2016 a junio de 2017. De manera general se puede adelantar que las presentes manifestaciones de violencia en Cancún y el continuo surgimiento de asentamientos irregulares ponen en evidencia la incapacidad institucional del Estado para planear y atender las necesidades de seguridad y vivienda de la población. Palabras clave: Cancún, economía, migración, violencia, asentamientos.   Resumo: O presente texto ofrece uma aproximação das condiçõe atuais de violencia em dois assentamentos irregulares em Cancún, que se localiza no estado de Quintana Roo, México, como consequência da migração de trabalhadores que aconteceu nesta localidade desde sua criação em 1970 como Centro Turístico Integral. Para elaborar este trabalho se realizou, ademáis da revisão bibliográfica, um estudo hemerográfico dos meios de comunicação locais e nacionais e um trabalho etnográfico nas colônias de El Milagro e Tres Reyes de abril de 2016 a junho de 2017. De maneira geral se pode antecipar que as presentes manifestações de violencia em Cancún e o contínuo surgimento de assentamentos irregulares colocam em evidencia a capacidade institucional do Estado para planejar e atender as necesidades de segurança e vivência da população. Palavras-chaves: Cancún; economía; migração; violencia; assentamentos.   Abstract: The present text offers an approximation to the current conditions of

Dynamics of long-period irregular pulsations in high latitudes during strong magnetic storms

International Nuclear Information System (INIS)

Kurazhkovskaya, N.A.; Klajn, B.I.

1995-01-01

Effects of strong magnetic storms within np type high-latitudinal long-period irregular pulsations at Mirny studied using data obtained at observatory of the magnetosphere south hemisphere. Variation of long-period irregular pulsation amplitude is shown to depend essentially on duration of storm initial phase and on the nature of solar wind heterogeneity enabling growth of strong storm. 14 refs

Electron microscopy of atmospheric particles

Science.gov (United States)

Huang, Po-Fu

Electron microscopy coupled with energy dispersive spectrometry (EM/EDS) is a powerful tool for single particle analysis. However, the accuracy with which atmospheric particle compositions can be quantitatively determined by EDS is often hampered by substrate-particle interactions, volatilization losses in the low pressure microscope chamber, electron beam irradiation and use of inaccurate quantitation factors. A pseudo-analytical solution was derived to calculate the temperature rise due to the dissipation of the electron energy on a particle-substrate system. Evaporative mass loss for a spherical cap-shaped sulfuric acid particle resting on a thin film supported by a TEM grid during electron beam impingement has been studied. Measured volatilization rates were found to be in very good agreement with theoretical predictions. The method proposed can also be used to estimate the vapor pressure of a species by measuring the decay of X-ray intensities. Several types of substrates were studied. We found that silver-coated silicon monoxide substrates give carbon detection limits comparable to commercially available substrates. An advantage of these substrates is that the high thermal conductivity of the silver reduces heating due to electron beam impingement. In addition, exposure of sulfuric acid samples to ammonia overnight substantially reduces sulfur loss in the electron beam. Use of size-dependent k-factors determined from particles of known compositions shows promise for improving the accuracy of atmospheric particle compositions measured by EM/EDS. Knowledge accumulated during the course of this thesis has been used to analyze atmospheric particles (Minneapolis, MN) selected by the TDMA and collected by an aerodynamic focusing impactor. 'Less' hygroscopic particles, which do not grow to any measurable extent when humidified to ~90% relative humidity, included chain agglomerates, spheres, flakes, and irregular shapes. Carbon was the predominant element detected in

Laboratory evaluation of a gasifier particle sampling system using model compounds of different particle morphology

Energy Technology Data Exchange (ETDEWEB)

Nilsson, Patrik T.; Malik, Azhar; Pagels, Joakim; Lindskog, Magnus; Rissler, Jenny; Gudmundsson, Anders; Bohgard, Mats; Sanati, Mehri [Lund University, Division of Ergonomics and Aerosol Technology, P.O. Box 118, Lund (Sweden)

2011-07-15

The objective of this work was to design and evaluate an experimental setup to be used for field studies of particle formation in biomass gasification processes. The setup includes a high-temperature dilution probe and a denuder to separate solid particles from condensable volatile material. The efficiency of the setup to remove volatile material from the sampled stream and the influence from condensation on particles with different morphologies is presented. In order to study the sampling setup model, aerosols were created with a nebulizer to produce compact and solid KCl particles and a diffusion flame burner to produce agglomerated and irregular soot particles. The nebulizer and soot generator was followed by an evaporation-condensation section where volatile material, dioctylsebacete (DOS), was added to the system as a tar model compound. The model aerosol particles were heated to 200 C to create a system containing both solid particles and volatile organic material in gas phase. The heated aerosol particles were sampled and diluted at the same temperature with the dilution probe. Downstream the probe, the DOS was adsorbed in the denuder. This was achieved by slowly decreasing the temperature of the diluted sample towards ambient level in the denuder. Thereby the supersaturation of organic vapors was reduced which decreased the probability for tar condensation and nucleation of new particles. Both the generation system and the sampling technique gave reproducible results. A DOS collection efficiency of >99% was achieved if the denuder inlet concentration was diluted to less than 1-6 mg/m{sup 3} depending on the denuder flow rate. Concentrations higher than that lead to significant impact on the resulting KCl size distribution. The choice of model compounds was done to study the effect from the particle morphology on the achieved particle characteristics after the sampling setup. When similar amounts of volatile material condensed on soot agglomerates and

Refraction traveltime tomography based on damped wave equation for irregular topographic model

Science.gov (United States)

Park, Yunhui; Pyun, Sukjoon

2018-03-01

Land seismic data generally have time-static issues due to irregular topography and weathered layers at shallow depths. Unless the time static is handled appropriately, interpretation of the subsurface structures can be easily distorted. Therefore, static corrections are commonly applied to land seismic data. The near-surface velocity, which is required for static corrections, can be inferred from first-arrival traveltime tomography, which must consider the irregular topography, as the land seismic data are generally obtained in irregular topography. This paper proposes a refraction traveltime tomography technique that is applicable to an irregular topographic model. This technique uses unstructured meshes to express an irregular topography, and traveltimes calculated from the frequency-domain damped wavefields using the finite element method. The diagonal elements of the approximate Hessian matrix were adopted for preconditioning, and the principle of reciprocity was introduced to efficiently calculate the Fréchet derivative. We also included regularization to resolve the ill-posed inverse problem, and used the nonlinear conjugate gradient method to solve the inverse problem. As the damped wavefields were used, there were no issues associated with artificial reflections caused by unstructured meshes. In addition, the shadow zone problem could be circumvented because this method is based on the exact wave equation, which does not require a high-frequency assumption. Furthermore, the proposed method was both robust to an initial velocity model and efficient compared to full wavefield inversions. Through synthetic and field data examples, our method was shown to successfully reconstruct shallow velocity structures. To verify our method, static corrections were roughly applied to the field data using the estimated near-surface velocity. By comparing common shot gathers and stack sections with and without static corrections, we confirmed that the proposed tomography

Evaluation of statistical methods for quantifying fractal scaling in water-quality time series with irregular sampling

Science.gov (United States)

Zhang, Qian; Harman, Ciaran J.; Kirchner, James W.

2018-02-01

River water-quality time series often exhibit fractal scaling, which here refers to autocorrelation that decays as a power law over some range of scales. Fractal scaling presents challenges to the identification of deterministic trends because (1) fractal scaling has the potential to lead to false inference about the statistical significance of trends and (2) the abundance of irregularly spaced data in water-quality monitoring networks complicates efforts to quantify fractal scaling. Traditional methods for estimating fractal scaling - in the form of spectral slope (β) or other equivalent scaling parameters (e.g., Hurst exponent) - are generally inapplicable to irregularly sampled data. Here we consider two types of estimation approaches for irregularly sampled data and evaluate their performance using synthetic time series. These time series were generated such that (1) they exhibit a wide range of prescribed fractal scaling behaviors, ranging from white noise (β = 0) to Brown noise (β = 2) and (2) their sampling gap intervals mimic the sampling irregularity (as quantified by both the skewness and mean of gap-interval lengths) in real water-quality data. The results suggest that none of the existing methods fully account for the effects of sampling irregularity on β estimation. First, the results illustrate the danger of using interpolation for gap filling when examining autocorrelation, as the interpolation methods consistently underestimate or overestimate β under a wide range of prescribed β values and gap distributions. Second, the widely used Lomb-Scargle spectral method also consistently underestimates β. A previously published modified form, using only the lowest 5 % of the frequencies for spectral slope estimation, has very poor precision, although the overall bias is small. Third, a recent wavelet-based method, coupled with an aliasing filter, generally has the smallest bias and root-mean-squared error among all methods for a wide range of

Electromagnetic field of a circular beam of relativistic particles

International Nuclear Information System (INIS)

Vybiral, B.

1978-01-01

The generalized Coulomb law and the generalized Biot-Savart-Laplace law are derived for an element of a beam of charged relativistic particles moving generally irregularly. These laws are utilized for the description of an electromagnetic field of a circular beam of relativistic regularly moving particles. It is shown that in the points on the axis of the beam the intensity of the electric field is given by an expression precisely corresponding to the classical Coulomb law for charges at rest and the induction of the magnetic field corresponds to the classical Biot-Savart-Laplace law for conductive currents. From the numerical solution it follows that in the points outside the axis the induction of the magnetic field rises with the velocity of the particles. For a velocity nearing that of light in vacuum it assumes a definite value (with the exception of the points lying on the beam). (author)

Justice: A Problem for Military Ethics during Irregular War

National Research Council Canada - National Science Library

Bauer, John W

2008-01-01

... is?" or "Justice according to whom?" The relative nature of the term "justice" creates a problem for military ethics, particularly when soldiers try to determine what actions are morally acceptable when they are engaged in irregular warfare...

A Generalized FDM for solving the Poisson's Equation on 3D Irregular Domains

Directory of Open Access Journals (Sweden)

J. Izadian

2014-01-01

Full Text Available In this paper a new method for solving the Poisson's equation with Dirichlet conditions on irregular domains is presented. For this purpose a generalized finite differences method is applied for numerical differentiation on irregular meshes. Three examples on cylindrical and spherical domains are considered. The numerical results are compared with analytical solution. These results show the performance and efficiency of the proposed method.

Natural convection inside an irregular porous cavity

International Nuclear Information System (INIS)

Beltran, Jorge I. LLagostera; Trevisan, Osvair Vidal

1990-01-01

Natural convection flow induced by heating from below in a irregular porous cavity is investigated numerically. The influence of the modified Rayleigh number and geometric ratios on heat transfer and fluid flow is studied. Global and local Nusselt for Rayleigh numbers covering the range 0 - 1600 and for several geometric ratios. The fluid flow and the temperature field are illustrated by contour maps. (author)

Swiveling Lathe Jaw Concept for Holding Irregular Pieces

Science.gov (United States)

David, J.

1966-01-01

Clamp holds irregularly shaped pieces in lathe chuck without damage and eliminates excessive time in selecting optimum mounting. Interchangeable jaws ride in standard jaw slots but swivel so that the jaw face bears evenly against the workpiece regardless of contour. The jaws can be used on both engine and turret lathes.

A Key Experiment of Quantum Optics: The Transfer of Spin Angular Momentum from Photons to a Birefringent Particle

Energy Technology Data Exchange (ETDEWEB)

Frins, E [Universidad de la Republica, Montevideo (Uruguay); Dultz, W [J.W.v.Goethe Universitaet Frankfurt/Main (Germany); Schmitzer, H, E-mail: requalivahanus@t-online.de [Xavier University, Cincinnati (United States)

2011-01-01

Rotating small birefringent particles with the spin angular momentum of light is a key experiment of quantum optics. We derive the equation of motion of small retarders in viscose liquids, demonstrate their some times irregular rotation in polarized light, and discuss possible technical applications.

The scholarly rebellion of the early Baker Street Irregulars

Directory of Open Access Journals (Sweden)

George Mills

2017-03-01

Full Text Available This work provides and analyzes an early institutional history of the pioneering Sherlock Holmes American fan club, the Baker Street Irregulars (BSI. Using the publications and records of these devoted Sherlockians, I track the BSI's development from a speakeasy gathering in 1934 to a national organization by the mid-1940s. This growth was built on a foundation of Victorian nostalgia and playful humor. Yet at the same time the members of the Irregulars took their fandom seriously, producing Sherlockian scholarship and creating an infrastructure of journals, conferences, and credentialing that directly mimicked the academy. They positioned themselves in contrast to prevailing scholarly practices of the period, such as New Criticism. I trace both how their fan practices developed over time and how this conflict with the academy led to many of the BSI's defining characteristics.

Rocket measurements of electron density irregularities during MAC/SINE

Science.gov (United States)

Ulwick, J. C.

1989-01-01

Four Super Arcas rockets were launched at the Andoya Rocket Range, Norway, as part of the MAC/SINE campaign to measure electron density irregularities with high spatial resolution in the cold summer polar mesosphere. They were launched as part of two salvos: the turbulent/gravity wave salvo (3 rockets) and the EISCAT/SOUSY radar salvo (one rocket). In both salvos meteorological rockets, measuring temperature and winds, were also launched and the SOUSY radar, located near the launch site, measured mesospheric turbulence. Electron density irregularities and strong gradients were measured by the rocket probes in the region of most intense backscatter observed by the radar. The electron density profiles (8 to 4 on ascent and 4 on descent) show very different characteristics in the peak scattering region and show marked spatial and temporal variability. These data are intercompared and discussed.

Spiking irregularity and frequency modulate the behavioral report of single-neuron stimulation.

Science.gov (United States)

Doron, Guy; von Heimendahl, Moritz; Schlattmann, Peter; Houweling, Arthur R; Brecht, Michael

2014-02-05

The action potential activity of single cortical neurons can evoke measurable sensory effects, but it is not known how spiking parameters and neuronal subtypes affect the evoked sensations. Here, we examined the effects of spike train irregularity, spike frequency, and spike number on the detectability of single-neuron stimulation in rat somatosensory cortex. For regular-spiking, putative excitatory neurons, detectability increased with spike train irregularity and decreasing spike frequencies but was not affected by spike number. Stimulation of single, fast-spiking, putative inhibitory neurons led to a larger sensory effect compared to regular-spiking neurons, and the effect size depended only on spike irregularity. An ideal-observer analysis suggests that, under our experimental conditions, rats were using integration windows of a few hundred milliseconds or more. Our data imply that the behaving animal is sensitive to single neurons' spikes and even to their temporal patterning. Copyright © 2014 Elsevier Inc. All rights reserved.

Zonal drifts of ionospheric irregularities at temperate latitude in the Indian region

Directory of Open Access Journals (Sweden)

S. Kumar

1995-07-01

Full Text Available The systematic time differences observed in the onset of postsunset VHF scintillations recorded simultaneously at Ujjain (Geogr. lat. 23.2°N, Geogr. long. 75.6°E and Bhopal (Geogr. lat. 23.2°N, Geogr. long. 77.6°E, situated at the peak of the anomaly crest in the Indian region, have been analysed to determine the zonal drifts of scintillation-producing irregularities. The method is based on the assumption that the horizontal movement of irregularities does not change while crossing the F-region cross-over points of these stations. The calculated velocities of irregularities indicate an eastward drift decreasing from about 180 m s–1 to 55 m s–1 during the course of night. In the premidnight period, the drifts are reduced under the magnetically disturbed conditions. The average east-west extension of irregularites is found to be in the range of 200–500 km.

Institutional Root Cause of the Irregularity of Social Security Funds in China

Institute of Scientific and Technical Information of China (English)

Bingwen Zheng

2007-01-01

This paper analyzes institutional defects in the Chinese social security system, based on irregularities in social security funds revealed in the Audit Report by the China National Audit Office. The author divides the irregularities into five categories according to the nature of fund use. The results show that the institutional root cause of the irregularities lies in the unreasonable design and operation of the social security system, which currently faces management and institutional risks. This paper argues that simple rhetoric about strengthening regulation and supervision cannot help to reduce illegal practices, or to realize risk control. The only solution is to reform the social security system. Specifically, the Chinese Government should regulate the administrative cost of the social security system,and the behavior of its agencies, through legislation, reform the investment regime to increase rate of return of pension assets, and adjust and reshape the existing social security system, so as to elevate its pooling level.

Characteristics of low latitude ionospheric E-region irregularities ...

Indian Academy of Sciences (India)

154°E, dip angle = 37.3°, sub-ionospheric dip = 34°) have been analyzed to study the behaviour of ionospheric E-region irregularities during the active solar and magnetic periods. The autocorrelation functions, power spectral densities, signal de-correlation times are computed to study the temporal features of ionospheric ...

Randomness control of vehicular motion through a sequence of traffic signals at irregular intervals

International Nuclear Information System (INIS)

Nagatani, Takashi

2010-01-01

We study the regularization of irregular motion of a vehicle moving through the sequence of traffic signals with a disordered configuration. Each traffic signal is controlled by both cycle time and phase shift. The cycle time is the same for all signals, while the phase shift varies from signal to signal by synchronizing with intervals between a signal and the next signal. The nonlinear dynamic model of the vehicular motion is presented by the stochastic nonlinear map. The vehicle exhibits the very complex behavior with varying both cycle time and strength of irregular intervals. The irregular motion induced by the disordered configuration is regularized by adjusting the phase shift within the regularization regions.

Characterization of airborne particles in an open pit mining region.

Science.gov (United States)

Huertas, José I; Huertas, María E; Solís, Dora A

2012-04-15

We characterized airborne particle samples collected from 15 stations in operation since 2007 in one of the world's largest opencast coal mining regions. Using gravimetric, scanning electron microscopy (SEM-EDS), and X-ray photoelectron spectroscopy (XPS) analysis the samples were characterized in terms of concentration, morphology, particle size distribution (PSD), and elemental composition. All of the total suspended particulate (TSP) samples exhibited a log-normal PSD with a mean of d=5.46 ± 0.32 μm and σ(ln d)=0.61 ± 0.03. Similarly, all particles with an equivalent aerodynamic diameter less than 10 μm (PM(10)) exhibited a log-normal type distribution with a mean of d=3.6 ± 0.38 μm and σ(ln d)=0.55 ± 0.03. XPS analysis indicated that the main elements present in the particles were carbon, oxygen, potassium, and silicon with average mass concentrations of 41.5%, 34.7%, 11.6%, and 5.7% respectively. In SEM micrographs the particles appeared smooth-surfaced and irregular in shape, and tended to agglomerate. The particles were typically clay minerals, including limestone, calcite, quartz, and potassium feldspar. Copyright © 2012 Elsevier B.V. All rights reserved.

Shape of the nuclear magnetic resonance line in anisotropic superconductors with an irregular vortex lattice

International Nuclear Information System (INIS)

Minkin, A.V.; Tsarevskij, S.L.

2006-01-01

For high-temperature superconductors the shape of a NMR spectrum line is built regarding for variation of inhomogeneity of irregular vortex lattice magnetic field near superconductor surface. It is shown that the shape of a NMR line is not simply widened but noticeably varies depending on the degree of irregularity of a superconductor vortex lattice. This variation is associated with a local symmetry decrease in an irregular vortex lattice of the superconductor. Taking into account these circumstances may considerably change conclusions about the type of a vortex lattice and superconductor parameters which are commonly gained from NMR line shape analysis [ru

Improving Transactional Memory Performance for Irregular Applications

OpenAIRE

Pedrero, Manuel; Gutiérrez, Eladio; Romero, Sergio; Plata, Óscar

2015-01-01

Transactional memory (TM) offers optimistic concurrency support in modern multicore archi- tectures, helping the programmers to extract parallelism in irregular applications when data dependence information is not available before runtime. In fact, recent research focus on ex- ploiting thread-level parallelism using TM approaches. However, the proposed techniques are of general use, valid for any type of application. This work presents ReduxSTM, a software TM system specially d...

Morning Cortisol Levels and Perceived Stress in Irregular Shift Workers Compared with Regular Daytime Workers

Directory of Open Access Journals (Sweden)

Harri Lindholm

2012-01-01

Full Text Available The 24/7 work environment and irregular shifts may markedly enhance the psychological pressure of media work. Changes in the hypothalamic-pituitary-adrenal axis reflect adaptation to stress. We analysed the correlation between subjective stress, sleep, salivary cortisol, and melatonin hormones among Finnish media workers with regular daytime work (RDW and with irregular shift work (ISW while controlling confounders. From 874 employees with regular daytime work or with irregular shift work, 70 employees from both groups were randomly selected. The final number of employees with a complete salivary cortisol profile was 66 in the RDW group and 65 in the ISW group. Five saliva samples were gathered from each subject before and during a working day. The salivary cortisol level of the sample taken 60 minutes after awakening (T1 was compared to the salivary cortisol level taken immediately after awakening (T0, T1/T0 ratio. The ratio was higher in the ISW group than in RDW group. Irregular shift work (P<0.001, severe stress (P<0.05, and less sleep (P<0.05 were independently associated with an augmented cortisol response after awakening. A stressful work environment and irregular shift work enhance cortisol excretion after waking. In the long run, this may become detrimental to health.

Evaluation of statistical methods for quantifying fractal scaling in water-quality time series with irregular sampling

Directory of Open Access Journals (Sweden)

Q. Zhang

2018-02-01

Full Text Available River water-quality time series often exhibit fractal scaling, which here refers to autocorrelation that decays as a power law over some range of scales. Fractal scaling presents challenges to the identification of deterministic trends because (1 fractal scaling has the potential to lead to false inference about the statistical significance of trends and (2 the abundance of irregularly spaced data in water-quality monitoring networks complicates efforts to quantify fractal scaling. Traditional methods for estimating fractal scaling – in the form of spectral slope (β or other equivalent scaling parameters (e.g., Hurst exponent – are generally inapplicable to irregularly sampled data. Here we consider two types of estimation approaches for irregularly sampled data and evaluate their performance using synthetic time series. These time series were generated such that (1 they exhibit a wide range of prescribed fractal scaling behaviors, ranging from white noise (β  =  0 to Brown noise (β  =  2 and (2 their sampling gap intervals mimic the sampling irregularity (as quantified by both the skewness and mean of gap-interval lengths in real water-quality data. The results suggest that none of the existing methods fully account for the effects of sampling irregularity on β estimation. First, the results illustrate the danger of using interpolation for gap filling when examining autocorrelation, as the interpolation methods consistently underestimate or overestimate β under a wide range of prescribed β values and gap distributions. Second, the widely used Lomb–Scargle spectral method also consistently underestimates β. A previously published modified form, using only the lowest 5 % of the frequencies for spectral slope estimation, has very poor precision, although the overall bias is small. Third, a recent wavelet-based method, coupled with an aliasing filter, generally has the smallest bias and root-mean-squared error among

Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

Science.gov (United States)

De Moraes, Carlos Gustavo V.; Prata, Tiago S.; Liebmann, Jeffrey; Ritch, Robert

2010-01-01

Recent advances in tonometry have led to the development of a number of devices with differing clinical applications. Their role in cases of abnormal corneal thickness and surface irregularities is particularly important, as inaccurate estimation of the true intraocular pressure (IOP) in such cases may lead to suboptimal evaluation. The purpose of the present review was to evaluate the accuracy of the most widely used devices in cases of corneal thickness and surface irregularities, based on a survey of the published literature. The analysis was based on a Medline search focusing mainly on papers that have evaluated the devices’ accuracy with respect to corneal thickness and irregularities. Nine device types (Goldmann tonometer, Tono-Pen, Perkins tonometer, Ocular Response Analyzer, non-contact tonometer, pneumatonometer, I-Care rebound tonometer, Pascal dynamic contour tonometer (DCT) and Phosphene tonometer) were described in detail. Moreover, the physical principles and major utility of each tonometer were compared. Each of the many different commercially available tonometers has specific advantages and disadvantages. New non-invasive technologies are getting closer to a precise estimation of the true IOP. However, among all tonometers, none is highly accurate when both corneal thickness and surface irregularities are present. Fifty years after its development, Goldmann tonometry remains the gold standard to which all other devices are compared.

Using Radio Irregularity for Increasing Residential Energy Awareness

Directory of Open Access Journals (Sweden)

A. Miljković

2012-06-01

Full Text Available Radio irregularity phenomenon is often considered as a shortcoming of wireless networks. In this paper, the method of using radio irregularity as an efficient human presence detection sensor in smart homes is presented. The method is mainly based on monitoring variations of the received signal strength indicator (RSSI within the messages used for the communication between wireless smart power outlets. The radio signals used for the inter-outlets communication can be absorbed, diffracted or reflected by objects in their propagation paths. When a human enters the existing radio communication field, the variation of the signal strength at the receiver is even more expressed. Based on the detected changes and compared to the initial thresholds set during the initialization phase, the system detects human presence. The proposed solution increases user awareness and automates the power control in households, with the primary goal to contribute in residential energy savings. Compared to conventional sensor networks, this approach preserves the sensorial intelligence, simplicity and low installation costs, without the need for additional sensors integration.

Very high latitude F-region irregularities observed by HF-radar backscatter

International Nuclear Information System (INIS)

Baker, K.B.; Greenwald, R.A.; Tsunoda, R.T.

1983-01-01

In February and March, 1982, a coherent scatter HF radar was operated from Cleary, Alaska to observe 7- to 15-m wavelength F-region plasma irregularities near the poleward edge of the auroral zone and in the polar cap. The radar operated for five days from February 25 to March 1 and produced approximately 700,000 Doppler spectra during that time. Of those nearly 700,000 spectra, approximately 10% showed backscattered power 3 dB or more above the noise level. A ray tracing technique using electron densities determined by the Chatanika incoherent scatter radar was used to predict locations where the HF waves were approximately normal to the magnetic field. If those locations were also to contain small scale electron density structure, then one would expect them to backscatter the HF waves. Several comparisons were made between predicted and observed locations of radiowave backscatter and excellent agreement was obtained. In addition, comparisons of the Doppler velocities observed by the coherent scatter HF radar and those observed by the Chatanika radar showed good agreement, suggesting that the plasma irregularities observed by the HF radar drift with the ambient plasma. In addition, average vector velocities calculated for the entire 5-day period show a flow pattern consistent with polar cap convection models. This again indicates that the irregularities drift with the plasma, as is predicted by a number of theories of F-region plasma irregularities. In the summer of 1983, the research program begun with those measurements will be continued with a steerable phased-array HF radar located at Goose Bay, Labrador, that will view the same ionospheric region as does the Sondre Stromfjord incoherent scatter radar

Interagency Cooperation for Irregular Warfare at the Combatant Command

Science.gov (United States)

2009-01-01

enemy’s command capability.16 Salamoni argued that the term “irregular warfare” belies an ethnocentric perspective of conflict that will limit military...duty military staffing to form the nucleus of the organization, which would receive augmentation from additional assigned reservists and interagency

Simultaneous observations of ESF irregularities over Indian region using radar and GPS

Directory of Open Access Journals (Sweden)

S. Sripathi

2008-10-01

Full Text Available In this paper, we present simultaneous observations of temporal and spatial variability of total electron content (TEC and GPS amplitude scintillations on L1 frequency (1.575 GHz during the time of equatorial spread F (ESF while the MST radar (53 MHz located at Gadanki (13.5° N, 79.2° E, Dip latitude 6.3° N, a low latitude station, made simultaneous observations. In particular, the latitudinal and longitudinal extent of TEC and L-band scintillations was studied in the Indian region for different types of ESF structures observed using the MST radar during the low solar activity period of 2004 and 2005. Simultaneous radar and GPS observations during severe ESF events in the pre-midnight hour reveal that significant GPS L band scintillations, depletions in TEC, and the double derivative of the TEC index (DROTI, which is a measure of fluctuations in TEC, obtained at low latitudes coincide with the appearance of radar echoes at Gadanki. As expected, when the irregularities reach higher altitudes as seen in the radar map during pre-midnight periods, strong scintillations on an L-band signal are observed at higher latitudes. Conversely, when radar echoes are confined to only lower altitudes, weak scintillations are found and their latitudinal extent is small. During magnetically quiet periods, we have recorded plume type radar echoes during a post-midnight period that is devoid of L-band scintillations. Using spectral slopes and cross-correlation index of the VHF scintillation observations, we suggest that these irregularities could be "dead" or "fossil" bubbles which are just drifting in from west. This scenario is consistent with the observations where suppression of pre-reversal enhancement (PRE in the eastward electric field is indicated by ionosonde observations of the height of equatorial F layer and also occurrence of low spectral width in the radar observations relative to pre-midnight period. However, absence of L-band scintillations during

Lateralized effects of orthographical irregularity and auditory memory load on the kinematics of transciption typewriting

NARCIS (Netherlands)

Bloemsaat, J.G.; Galen, G.P. van; Meulenbroek, R.G.J.

2003-01-01

This study investigated the combined effects of orthographical irregularity and auditory memory load on the kinematics of finger movements in a transcription-typewriting task. Eight right-handed touch-typists were asked to type 80 strings of ten seven-letter words. In half the trials an irregularly

Magnetic storm effect on the occurrence of ionospheric irregularities at an equatorial station in the African sector

Directory of Open Access Journals (Sweden)

Olushola Abel Oladipo

2014-01-01

Full Text Available Large-scale ionospheric irregularities usually measured by GPS TEC fluctuation indices are regular occurrence at the equatorial region shortly after sunset around solar maximum. Magnetic storm can trigger or inhibit the generation of these irregularities depending on the local time the main phase of a particular storm occurs. We studied the effect of nine (9 distinct storms on the occurrence of ionospheric irregularities at Fraceville in Gabon (Lat = −1.63˚, Long = 13.55˚, dip lat. = −15.94˚, an equatorial station in the African sector. These storms occurred between November 2001 and September 2002. We used TEC fluctuation indices (i.e. ROTI and ROTIAVE estimated from 30 s interval Rinex data and also we used the storm indices (i.e. Dst, dDst/dt, and IMF BZ to predict the likely effect of each storm on the irregularities occurrence at this station. The results obtained showed that most of the storms studied inhibited ionospheric irregularities. Only one out of all the storms studied (i.e. September 4, 2002 storms with the main phase on the night of September 7-8 triggered post-midnight ionospheric irregularities. There are two of the storms during which ionospheric irregularities were observed. However, these may not be solely attributed to the storms event because the level of irregularities observed during these two storms is comparable to that observed during previous days before the storms. For this station and for the storms investigated, it seems like a little modification to the use of Aarons categories in terms of the local time the maximum negative Dst occurs could lead to a better prediction. However, it would require investigating many storms during different level of solar activities and at different latitudes to generalize this modification.

Coherent and intermittent ensemble oscillations emerge from networks of irregular spiking neurons.

Science.gov (United States)

Hoseini, Mahmood S; Wessel, Ralf

2016-01-01

Local field potential (LFP) recordings from spatially distant cortical circuits reveal episodes of coherent gamma oscillations that are intermittent, and of variable peak frequency and duration. Concurrently, single neuron spiking remains largely irregular and of low rate. The underlying potential mechanisms of this emergent network activity have long been debated. Here we reproduce such intermittent ensemble oscillations in a model network, consisting of excitatory and inhibitory model neurons with the characteristics of regular-spiking (RS) pyramidal neurons, and fast-spiking (FS) and low-threshold spiking (LTS) interneurons. We find that fluctuations in the external inputs trigger reciprocally connected and irregularly spiking RS and FS neurons in episodes of ensemble oscillations, which are terminated by the recruitment of the LTS population with concurrent accumulation of inhibitory conductance in both RS and FS neurons. The model qualitatively reproduces experimentally observed phase drift, oscillation episode duration distributions, variation in the peak frequency, and the concurrent irregular single-neuron spiking at low rate. Furthermore, consistent with previous experimental studies using optogenetic manipulation, periodic activation of FS, but not RS, model neurons causes enhancement of gamma oscillations. In addition, increasing the coupling between two model networks from low to high reveals a transition from independent intermittent oscillations to coherent intermittent oscillations. In conclusion, the model network suggests biologically plausible mechanisms for the generation of episodes of coherent intermittent ensemble oscillations with irregular spiking neurons in cortical circuits. Copyright © 2016 the American Physiological Society.

Young Japanese college students with dysmenorrhea have high frequency of irregular menstruation and premenstrual symptoms.

Science.gov (United States)

Fujiwara, Tomoko; Nakata, Rieko

2007-01-01

In this study, to estimate the current status of young women with menstrual disorders, the relation among dysmenorrhea, irregular menstruation and premenstrual symptoms was investigated by a questionnaire. Subjects ranging from 18 to 20 years old were recruited from 522 female students at Ashiya College in Japan. The intensity of dysmenorrhea was classified into 3 grades (score 1, not requiring analgesic; score 2, painful, requiring analgesic; score 3, painful, not relieved by analgesic). All participants were further divided into subsequent groups as having premenstrual symptoms or not and those having regular or irregular menstruation. Dysmenorrhea scores in the students with premenstrual symptoms or irregular menstruation were significantly higher than those without these symptoms (1.66+/-0.66 vs 1.41+/-0.59; 1.62+/-0.68 vs 1.49+/-0.61, respectively). There was no significant relation in the incidence between premenstrual symptoms and irregular menstruation. These findings suggest that considerable numbers of young women with dysmenorrhea are associated with premenstrual symptoms.

Constructing C1 Continuous Surface on Irregular Quad Meshes

Institute of Scientific and Technical Information of China (English)

HE Jun; GUO Qiang

2013-01-01

A new method is proposed for surface construction on irregular quad meshes as extensions to uniform B-spline surfaces. Given a number of control points, which form a regular or irregular quad mesh, a weight function is constructed for each control point. The weight function is defined on a local domain and is C1 continuous. Then the whole surface is constructed by the weighted combination of all the control points. The property of the new method is that the surface is defined by piecewise C1 bi-cubic rational parametric polynomial with each quad face. It is an extension to uniform B-spline surfaces in the sense that its definition is an analogy of the B-spline surface, and it produces a uniform bi-cubic B-spline surface if the control mesh is a regular quad mesh. Examples produced by the new method are also included.

Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

OpenAIRE

Carlos Gustavo V. De Moraes; Tiago S. Prata; Jeffrey Liebmann; Robert Ritch

2008-01-01

Recent advances in tonometry have led to the development of a number of devices with differing clinical applications. Their role in cases of abnormal corneal thickness and surface irregularities is particularly important, as inaccurate estimation of the true intraocular pressure (IOP) in such cases may lead to suboptimal evaluation. The purpose of the present review was to evaluate the accuracy of the most widely used devices in cases of corneal thickness and surface irregularities, based ...

Effects of irregular-shift work and physical activity on cardiovascular risk factors in truck drivers

Directory of Open Access Journals (Sweden)

Elaine Cristina Marqueze

2013-06-01

Full Text Available OBJECTIVE: To analyze the putative effect of type of shift and its interaction with leisure-time physical activity on cardiovascular risk factors in truck drivers. METHODS: A cross-sectional study was undertaken on 57 male truck drivers working at a transportation company, of whom 31 worked irregular shifts and 26 worked on the day-shift. Participants recorded their physical activity using the International Physical Activity Questionnaire along with measurements of blood pressure, body mass index and waist-hip ratio. Participants also provided a fasting blood sample for analysis of lipid-related outcomes. Data were analyzed using a factorial model which was covariate-controlled for age, smoking, work demand, control at work and social support. RESULTS: Most of the irregular-shift and day-shift workers worked more than 8 hours per day (67.7% and 73.1%, respectively. The mean duration of experience working the irregular schedule was 15.7 years. Day-shift workers had never engaged in irregular-shift work and had been working as a truck driver for 10.8 years on average. The irregular-shift drivers had lower work demand but less control compared to day-shift drivers (p < 0.05. Moderately-active irregular-shift workers had higher systolic and diastolic arterial pressures (143.7 and 93.2 mmHg, respectively than moderately-active day-shift workers (116 and 73.3 mmHg, respectively (p < 0.05 as well as higher total cholesterol concentrations (232.1 and 145 mg/dl, respectively (p = 0.01. Irrespective of their physical activity, irregular-shift drivers had higher total cholesterol and LDL-cholesterol concentrations (211.8 and 135.7 mg/dl, respectively than day-shift workers (161.9 and 96.7 mg/dl, respectively (ANCOVA, p < 0.05. CONCLUSIONS: Truck drivers are exposed to cardiovascular risk factors due to the characteristics of the job, such as high work demand, long working hours and time in this profession, regardless of shift type or leisure-time physical

Scattering by non-spherical particles of size comparable to a wavelength - A new semi-empirical theory. [atmospheric radiative transfer

Science.gov (United States)

Pollack, J. B.; Cuzzi, J. N.

1978-01-01

Mie theory, which is generally used to describe the scattering behavior of particles at a certain wavelength, is only rigorously correct for spherical particles. Particles found as atmospheric constituents, with the exception of cloud droplets, are, however, decidedly nonspherical. An investigation is, therefore, conducted regarding the significant ways in which the scattering behavior of irregularly shaped particles differs from that of spheres. A systematic method is formulated for treating the real scalar scattering behavior. A description is presented of a new semiempirical theory based on simple physical principles and data obtained in laboratory measurements, which successfully reproduces the single scattering phase function for a wide range of particle shapes, sizes, and refractive indices.

Turbulence and particle acceleration

International Nuclear Information System (INIS)

Scott, J.S.

1975-01-01

A model for the production of high energy particles in the supernova remnant Cas A is considered. The ordered expansion of the fast moving knots produce turbulent cells in the ambient interstellar medium. The turbulent cells act as magnetic scattering centers and charged particles are accelerated to large energies by the second order Fermi mechanism. Model predictions are shown to be consistent with the observed shape and time dependence of the radio spectrum, and with the scale size of magnetic field irregularities. Assuming a galactic supernova rate at 1/50 yr -1 , this mechanism is capable of producing the observed galactic cosmic ray flux and spectrum below 10 16 eV/nucleon. Several observed features of galactic cosmic rays are shown to be consistent with model predictions. A model for the objects known as radio tall galaxies is also presented. Independent blobs of magnetized plasma emerging from an active radio galaxy into an intracluster medium become turbulent due to Rayleigh--Taylor and Kelvin--Helmholz instabilities. The turbulence produces both in situ betatron and 2nd order Fermi accelerations. Predictions of the dependence of spectral index and flux on distance along the tail match observations well. Fitting provides values of physical parameters in the blobs. The relevance of this method of particle acceleration for the problem of the origin of x-ray emission in clusters of galaxies is discussed

Cell structures caused by settling particles in turbulent Rayleigh-Bénard convection

Science.gov (United States)

Lee, Changhoon; Park, Sangro

2016-11-01

Turbulent thermal convection is an important phenomenon frequently found in nature and industrial processes, often with laden particles. In the last several decades, the vast majority of studies have addressed single phase convective flow with focus on the scaling relation of flow parameters associated with heat transfer. Particle-laden Rayleigh-Bénard convection, however, has not been sufficiently studied. In this study, modulation of cell structures by settling particles in turbulent Rayleigh-Bénard convection in a doubly periodic square channel is investigated using direct numerical simulation with a point particle approach. Flow parameters are fixed at Rayleigh number=106, Prandtl number=0.7, the aspect ratio=6, and Froude number=0.19. We report from the simulations that settling heavy particles modulate irregular large-scale thermal plume structures into organized polygonal cell structures. Different shapes of flow structures are obtained for different particle diameters and mass loadings. We found that polygonal cell structures arise due to asymmetric feedback force exerted by particles onto hot and cold plumes. Increasing the number of particles augments the asymmetry and the polygonal cell structures become smaller, eventually going to the hexagonal structures.

Detection of increase in corneal irregularity due to pterygium using Fourier series harmonic analyses with multiple diameters.

Science.gov (United States)

Minami, Keiichiro; Miyata, Kazunori; Otani, Atsushi; Tokunaga, Tadatoshi; Tokuda, Shouta; Amano, Shiro

2018-05-01

To determine steep increase of corneal irregularity induced by advancement of pterygium. A total of 456 eyes from 456 consecutive patients with primary pterygia were examined for corneal topography and advancement of pterygium with respect to the corneal diameter. Corneal irregularity induced by the pterygium advancement was evaluated by Fourier harmonic analyses of the topographic data that were modified for a series of analysis diameters from 1 mm to 6 mm. Incidences of steep increases in the asymmetry or higher-order irregularity components (inflection points) were determined by using segmented regression analysis for each analysis diameter. The pterygium advancement ranged from 2% to 57%, with a mean of 22.0%. Both components showed steep increases from the inflection points. The inflection points in the higher-order irregularity component altered with the analysis diameter (14.0%-30.6%), while there was no alternation in the asymmetry components (35.5%-36.8%). For the former component, the values at the inflection points were obtained in a range of 0.16 to 0.25 D. The Fourier harmonic analyses for a series of analysis diameters revealed that the higher-order irregularity component increased with the pterygium advancement. The analysis results confirmed the precedence of corneal irregularity due to pterygium advancement.

The majority of irregular menstrual cycles in adolescence are ovulatory: results of a prospective study.

Science.gov (United States)

Peña, Alexia S; Doherty, Dorota A; Atkinson, Helen C; Hickey, Martha; Norman, Robert J; Hart, Roger

2018-03-01

While ovulation is most likely to occur in adolescent girls with regular menstrual cycles, there are limited data on the incidence of ovulation in girls with irregular menstrual cycles in early postmenarcheal years. The aim of the study was to evaluate the presence of ovulation in healthy postmenarcheal girls with irregular menstrual cycles. Prospective cohort study over 12 weeks including 40 healthy postmenarcheal girls recruited from the population-based cohort of adolescents from Western Australian Pregnancy Cohort (Raine) Study with irregular menstrual cycles defined by either menstrual cycles 35 days in duration or cycle length that varied from month to month by >4 days according to menstrual diaries. Ovulation defined by urinary pregnanediol-3α-glucuronide/creatinine measurements higher than three times above minimum value obtained from 12 samples (1 per week). Forty girls (37 Caucasians) with irregular menstrual cycles aged 15.1 (median (IQR) 14.9-15.4) years who were 2.3 (1.9-3.3) years postmenarche were assessed. Urinary pregnanediol-3α-glucuronide/creatinine values identified that 33 girls (82.5%) ovulated during the 3 months of observation and 7 girls had anovulatory cycles. Menstrual diaries collected for a median (IQR) of 159 (137.5-188.2) days showed median minimal and maximum menstrual cycle duration of 24 (11.5-29) and 38.5 (35-48) days, respectively. A large proportion of healthy adolescent girls with irregular menstrual cycles are still ovulating despite irregular and infrequent menses. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Long wavelength irregularities in the equatorial electrojet

OpenAIRE

Kudeki, E.; Farley, D. T.; Fejer, Bela G.

1982-01-01

We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach...

Equatorial Ionospheric Irregularities Study from ROCSAT Data

Science.gov (United States)

2017-10-20

UNLIMITED: PB Public Release 13. SUPPLEMENTARY NOTES 14. ABSTRACT Ionospheric irregularity/scintillation occurrences can be caused by external driving ...Academia Sinica, Taipei, Taiwan e-mail: chliu2@gate.sinica.edu.tw phone :886-3-4227151x34757 CoPI: Shin-Yi Su Institution: National Central...University, Chung-Li, Taiwan e-mail: sysu@csrsr.ncu.edu.tw phone :886-3-4227151x57643 CoPI: Lung-Chi Tsai Institution: National Central University, Chung-Li

Numerical Simulation of the Time Evolution of Small-Scale Irregularities in the F-Layer Ionospheric Plasma

Directory of Open Access Journals (Sweden)

O. V. Mingalev

2011-01-01

Full Text Available Dynamics of magnetic field-aligned small-scale irregularities in the electron concentration, existing in the F-layer ionospheric plasma, is investigated with the help of a mathematical model. The plasma is assumed to be a rarefied compound consisting of electrons and positive ions and being in a strong, external magnetic field. In the applied model, kinetic processes in the plasma are simulated by using the Vlasov-Poisson system of equations. The system of equations is numerically solved applying a macroparticle method. The time evolution of a plasma irregularity, having initial cross-section dimension commensurable with a Debye length, is simulated during the period sufficient for the irregularity to decay completely. The results of simulation indicate that the small-scale irregularity, created initially in the F-region ionosphere, decays accomplishing periodic damped vibrations, with the process being collisionless.

Packing Nonspherical Particles: All Shapes Are Not Created Equal

Science.gov (United States)

Torquato, Salvatore

2012-02-01

Over the past decade there has been increasing interest in the effects of particle shape on the characteristics of dense particle packings, since deviations from sphericity can lead to more realistic models of granular media, nanostructured materials, and tissue architecture. It is clear the that the broken rotational symmetry of a nonspherical particle is a crucial aspect in determining its resulting packing characteristics, but given the infinite variety of possible shapes (ellipsoids, superballs, regular and irregular polyhedra, etc.) it is desirable to formulate packing organizing principles based the particle shape. Such principles are beginning to be elucidated; see Refs. 1 and 2 and references therein. Depending upon whether the particle has central symmetry, inequivalent principle axes, and smooth or flat surfaces, we can describe the nature of its densest packing (which is typically periodic) as well as its disordered jammed states (which may or may not be isostatic). Changing the shape of a particle can dramatically alter its packing attributes. This tunability capability via particle shape could be used to tailor many-particle systems (e.g., colloids and granular media) to have designed crystal, liquid and glassy states. [4pt] [1] S. Torquato and F. H. Stillinger, ``Jammed Hard-Particle Packings: From Kepler to Bernal and Beyond," Rev. Modern Phys. 82, 2633 (2010). [0pt] [2] Y. Jiao and S. Torquato, Communication: ``A Packing of Truncated Tetrahedra That Nearly Fills All of Space and its Melting Properties," J. Chem. Phys. 135, 151101 (2011).

"Needed Not Wanted": An Interdisciplinary Examination of the Work-Related Challenges Faced by Irregular Migrants

Science.gov (United States)

Marfleet, Philip; Blustein, David L.

2011-01-01

Using an integrative perspective drawn from vocational psychology and migration studies, this article explores the lives of irregular migrants, which represents a unique aspect of work-based migration. Irregular migrants are those individuals who travel from regions without much work to states that offer some means of employment, without formal…

Working irregular shift patterns is associated with functional constipation among healthy trainee nurses

Directory of Open Access Journals (Sweden)

Ali Ebrahim

2017-11-01

Full Text Available The circadian system has a role in regulating gastrointestinal physiology. Perturbation of this system is associated with gastrointestinal tract dysfunction. Shiftwork and poor sleep quality are associated with functional gastrointestinal disorders among many professional groups. This study compared bowel habits between trainee nurses with regular and irregular patterns of shiftwork. Male and female nursing students, enrolled on the first year (regular shifts; n=49 and the fourth year (irregular shifts, n=48 of a nursing degree course were surveyed. Questionnaires were used to assess functional diarrhea and constipation over a three month period. The prevalence of functional constipation among regular shift workers was lower than that found among irregular shift workers; 31.3% and 61.2%, respectively. There was no difference between the two groups in relation to the prevalence of diarrhea. This suggests an association between shiftwork and functional constipation, but not with functional diarrhea.

Absorption and scattering properties of arbitrarily shaped particles in the Rayleigh domain

International Nuclear Information System (INIS)

Min, M.; Hovenier, J.W.; Dominik, C.; Koter, A. de; Yurkin, M.A.

2006-01-01

We provide a theoretical foundation for the statistical approach for computing the absorption properties of particles in the Rayleigh domain. We present a general method based on the discrete dipole approximation to compute the absorption and scattering properties of particles in the Rayleigh domain. The method allows to separate the geometrical aspects of a particle from its material properties. Doing the computation of the optical properties of a particle once, provides them for any set of refractive indices, wavelengths and orientations. This allows for fast computations of e.g. absorption spectra of arbitrarily shaped particles. Other practical applications of the method are in the interpretation of atmospheric and radar measurements as well as computations of the scattering matrix of small particles as a function of the scattering angle. In the statistical approach, the optical properties of irregularly shaped particles are represented by the average properties of an ensemble of particles with simple shapes. We show that the absorption cross section of an ensemble of arbitrarily shaped particles with arbitrary orientations can always be uniquely represented by the average absorption cross section of an ensemble of spheroidal particles with the same composition and fixed orientation. This proves for the first time that the statistical approach is generally viable in the Rayleigh domain

Women with minor menstrual irregularities have increased risk of preeclampsia and low birthweight in spontaneous pregnancies

DEFF Research Database (Denmark)

Bonnesen, Barbara; Oddgeirsdóttir, Hanna L; Naver, Klara Vinsand

2016-01-01

INTRODUCTION: Very few studies describe the obstetric and neonatal outcome of spontaneous pregnancies in women with irregular menstrual cycles. However, menstrual cycle irregularities are common and may be associated with increased risk, and women who develop pregnancy complications more frequent...

Targeting overall equipment efficiency for small medium enterprises with irregular production system

Science.gov (United States)

Prasetyawan, Y.; Suef, M.; Claudia, L.; Handayani, F. D.

2018-04-01

Overall Equipment Effectiveness (OEE) is widely used to measure the maturity of a production system. The company will be considered as World Class Manufacturing if it reaches more than 85% value, with near perfect value for availability, performance and quality factor. This assessment is usually taken on industries with regular production times named shift system. A typical 8 hours shift system is used in OEE measurement and performance monitoring. There are few Small to Medium Enterprise (SME) perform regular production times with shift systems, others using irregular production systems. The irregular production time in the SME production system is used because of demand fluctuations. This paper shows a quantitative analysis as a part of manufacturing system design to achieve a specific value of OEE for SME with irregular production systems, for individual businesses as well as collective business systems (some companies use the same production facilities for several processes). The results of experiments on several companies are presented, as a basis for determining the technical strategy of achieving OEE values.

Spectral element method for wave propagation on irregular domains

Indian Academy of Sciences (India)

A spectral element approximation of acoustic propagation problems combined with a new mapping method on irregular domains is proposed. Following this method, the Gauss–Lobatto–Chebyshev nodes in the standard space are applied to the spectral element method (SEM). The nodes in the physical space are ...

Wettability measurements of irregular shapes with Wilhelmy plate method

Science.gov (United States)

Park, Jaehyung; Pasaogullari, Ugur; Bonville, Leonard

2018-01-01

One of the most accurate methods for measuring the dynamic contact angle of liquids on solid surfaces is the Wilhelmy plate method. This method generally requires the use of rectangular samples having a constant perimeter in the liquid during advancing and receding cycles. A new formulation based on the Wilhelmy force balance equation to determine the contact angle for plate samples with irregular shapes has been developed. This method employs a profile plot obtained from an optical image to determine the perimeter (i.e. wetted length) of the sample as a function of the immersion depth. The raw force data measured by the force tensiometer is manipulated using the profile plot and the Wilhelmy equation to determine the wetting force and consequently advancing and the receding contact angle. This method is verified with both triangular and irregular PTFE samples in water, and measured contact angles are in good agreement with results from conventional regular shaped samples with a constant perimeter.

Effect of energy level sequences and neutron–proton interaction on α-particle preformation probability

International Nuclear Information System (INIS)

Ismail, M.; Adel, A.

2013-01-01

A realistic density-dependent nucleon–nucleon (NN) interaction with finite-range exchange part which produces the nuclear matter saturation curve and the energy dependence of the nucleon–nucleus optical model potential is used to calculate the preformation probability, S α , of α-decay from different isotones with neutron numbers N=124,126,128,130 and 132. We studied the variation of S α with the proton number, Z, for each isotone and found the effect of neutron and proton energy levels of parent nuclei on the behavior of the α-particle preformation probability. We found that S α increases regularly with the proton number when the proton pair in α-particle is emitted from the same level and the neutron level sequence is not changed during the Z-variation. In this case the neutron–proton (n–p) interaction of the two levels, contributing to emission process, is too small. On the contrary, if the proton or neutron level sequence is changed during the emission process, S α behaves irregularly, the irregular behavior increases if both proton and neutron levels are changed. This behavior is accompanied by change or rapid increase in the strength of n–p interaction

ARCAD3-SAFARI coordinated study of auroral and polar F-region ionospheric irregularities

International Nuclear Information System (INIS)

Villain, J.P.; Hanuise, C.; Beghin, C.

1985-01-01

Simultaneous observations of F-region ionospheric irregularities have been performed with the SAFARI ground based HF radars and the ISOPROBE experiment on board the AUREOL-3 satellite. Among seven orbits during which the satellite trajectory was directly in the radar beam or in the vicinity, four of them have been analysed in detail. The spectral power of the electron density variations ΔNe/Ne has been calculated for wavelengths between 20 m and 1 km from the ISOPROBE high time resolution thermal plasma measurements. One spectrum is obtained every 1.2 sec., which corresponds to about 10 km along the satellite trajectory. The SAFARI experiment is a set of two HF coherent radars located at Lycksele (Sweden) and Oulu (Finland). These radars are sensitive to F-region ionospheric irregularities of 10 m wavelength in the polar and auroral ionosphere. The phase velocity of the irregularities obtained from the Doppler spectrum is related to the ambient plasma drift. The presence of echoes observed with the SAFARI radars is compared with the spectral power of the electron density variations deduced from the ISOPROBE in-situ measurements. A good agreement is found between the two sets of observations and a numerical value of the spectral power corresponding to detection of echoes by the radar is given. A synoptical view of the event is given and interpreted according to the existing theories on plasma irregularities

Experimental evidence of widespread regions of small-scale plasma irregularities in the magnetosphere

International Nuclear Information System (INIS)

Holmgren, G.; Kintner, P.M.

1990-01-01

Small-scale (≤ 1 km) plasma irregularities have previously been observed in situ from the E region to an altitude of 8,000 km. In this paper the authors report results from the Viking plasma wave experiments which extends the measurements of high-latitude irregularities in two ways: (1) they have acquired electron density fluctuation measurements up to an altitude of 13,500 km and (2) for the first time a measurement technique was used that made a phase velocity deduction possible from in situ measurements. The spacecraft was equipped with two spatially separated Langmuir probes, each with an ability to measure relative probe current fluctuations with frequencies from dc to about 400 Hz. Under certain assumptions the current fluctuations could be interpreted as relative plasma density fluctuations, δn e /n e . Data from this interferometric instrument has been used to infer the distribution and nature of plasma irregularities along Viking orbits. It is demonstrated that the interferometric technique offers great advantages compared to single point measurements in this kind of study. It is shown that the observed small-scale plasma irregularities are nondispersive and convecting with the background plasma. They exhibit a power law frequency spectrum as observed in the satellite reference frame. The spectral index varies with location. An attempt to map source regions by identifying regions of high power and shallow spectrums is made

Effects of irregular two-dimensional and three-dimensional surface roughness in turbulent channel flows

International Nuclear Information System (INIS)

De Marchis, M.; Napoli, E.

2012-01-01

Highlights: ► 3D irregular rough surfaces produce higher effects than those observed over 2D. ► Effective slope is a geometrical parameter representative of the roughness effects. ► 3D rough surfaces enhance the turbulence isotropization. ► 2D and 3D irregular roughness partially support the wall similarity. ► Irregular rough surfaces shear some features with regular rough walls. - Abstract: Wall-resolved Large Eddy Simulation of fully developed turbulent channel flows over two different rough surfaces is performed to investigate on the effects of irregular 2D and 3D roughness on the turbulence. The two geometries are obtained through the superimposition of sinusoidal functions having random amplitudes and different wave lengths. In the 2D configuration the irregular shape in the longitudinal direction is replicated in the transverse one, while in the 3D case the sinusoidal functions are generated both in streamwise and spanwise directions. Both channel walls are roughened in such a way as to obtain surfaces with statistically equivalent roughness height, but different shapes. In order to compare the turbulence properties over the two rough walls and to analyse the differences with a smooth wall, the simulations are performed at the same Reynolds number Re τ = 395. The same mean roughness height h = 0.05δ (δ the half channel height) is used for the rough walls. The roughness function obtained with the 3D roughness is larger than in the 2D case, although the two walls share the same mean height. Thus, the considered irregular 3D roughness is more effective in reducing the flow velocity with respect to the 2D roughness, coherently with the literature results that identified a clear dependence of the roughness function on the effective slope (see ), higher in the generated 3D rough wall. The analysis of higher-order statistics shows that the effects of the roughness, independently on its two- or three-dimensional shape, are mainly confined in the inner

F region electron density irregularity spectra near Auroral acceleration and shear regions

International Nuclear Information System (INIS)

Basu, S.; Basu, S.; MacKenzie, E.; Coley, W.R.; Hanson, W.B.; Lin, C.S.

1984-01-01

Spectral characteristics of auroral F region irregularities were studied by the use of high-resolution (approx.35 m) density measurements made by the retarding potential analyzer (RPA) on board the Atmosphere Explorer D (AE-D) satellite during two orbits when the satellite was traversing the high-latitude ionosphere in the evening sector. Coordinated DMSP passes provided synoptic coverage of auroral activity. The auroral energy input was estimated by intergrating the low-energy electron (LEE) data on AE-D. It was found that the one-dimensional in situ spectral index (p 1 ) of the irregularities at scale lengths of 1 values of approx.-3. This is interpreted as resulting from the effects of E region conductivity on the F region irregularity structure. The regions in between the precipitation structures, where presumably the E region conductivity was small, were generally associated with large shears in the horizontal E-W drifts and large velocities, as measured by the ion drift meter on board AE-D. The maximum drifts measured were approx.2 km s -1 , corresponding to an electric field of 100 mV m -1 . The large-velocity regions were also associated with substantial ion heating and electron density depletions. The largest shear magnitudes observed were approx.80 m s -1 km -1 , and the shear gradient scale lengths were approx.10 km, which was approximately the resolution of the ion drift meter data set used. The spectral characteristics of irregularities in the large, variable flow regions were very different, with p 1 being approx.-1

Two media method for linear attenuation coefficient determination of irregular soil samples

International Nuclear Information System (INIS)

Vici, Carlos Henrique Georges

2004-01-01

In several situations of nuclear applications, the knowledge of gamma-ray linear attenuation coefficient for irregular samples is necessary, such as in soil physics and geology. This work presents the validation of a methodology for the determination of the linear attenuation coefficient (μ) of irregular shape samples, in such a way that it is not necessary to know the thickness of the considered sample. With this methodology irregular soil samples (undeformed field samples) from Londrina region, north of Parana were studied. It was employed the two media method for the μ determination. It consists of the μ determination through the measurement of a gamma-ray beam attenuation by the sample sequentially immersed in two different media, with known and appropriately chosen attenuation coefficients. For comparison, the theoretical value of μ was calculated by the product of the mass attenuation coefficient, obtained by the WinXcom code, and the measured value of the density sample. This software employs the chemical composition of the samples and supplies a table of the mass attenuation coefficients versus the photon energy. To verify the validity of the two media method, compared with the simple gamma ray transmission method, regular pome stone samples were used. With these results for the attenuation coefficients and their respective deviations, it was possible to compare the two methods. In this way we concluded that the two media method is a good tool for the determination of the linear attenuation coefficient of irregular materials, particularly in the study of soils samples. (author)

Multiple frequency radar observations of high-latitude E region irregularities in the HF modified ionosphere

International Nuclear Information System (INIS)

Noble, S.T.; Djuth, F.T.; Jost, R.J.

1987-01-01

In September 1983, experiments were conducted in Scandinavia using the high-power heating facility near Tromso, Norway. The purpose of the HF ionospheric modification experiments was to investigate the behavior of artificially produced E region irregularities at auroral latitudes. The majority of observations were made with backscatter radars operating at 46.9 and 143.8 MHz, but limited observations were also made at 21.4 and 140.0 MHz. These radars are sensitive to irregularities having scale lengths of between 1 and 7 m across the geomagnetic field lines. The growth and decay of the irregularities are scale length dependent with the shorter lengths growing and dissipating more rapidly than the longer lengths (e-folding growth times = 10 1 --10 2 ms; decay times = 10 2 --10 3 ms). During periods of full power ordinary mode heating, irregularities having peak cross sections of 10 4 m 2 at 46.9 MHz and 10 5 m 2 at 143.8 MHz are observed. However, the cross sections normally measured are 1 to 2 orders of magnitude smaller than the peak values. The cross sections are nonlinearly dependent on the HF power and begin to saturate at levels greater than 50--75 percent of full power. Past E and F region data from Arecibo are used in conjunction with the Tromso measurements to ascertain the relative roles played by various mechanisms in exciting irregularities. In the E region, the results tend to favor those instability processes which operate at the upper hybrid resonance level (e.g., thermal parametric and resonance instabilities) over those that operate at the reflection level (e.g., parametric decay instability). However, it is likely that anyh of the mechanisms studied could at times contribute to irregularity production in the E regions

Spectral element method for wave propagation on irregular domains

Indian Academy of Sciences (India)

Yan Hui Geng

2018-03-14

Mar 14, 2018 ... Abstract. A spectral element approximation of acoustic propagation problems combined with a new mapping method on irregular domains is proposed. Following this method, the Gauss–Lobatto–Chebyshev nodes in the standard space are applied to the spectral element method (SEM). The nodes in the ...

Lateralized effects of orthographical irregularity and auditory memory load on the kinematics of transcription typewriting.

Science.gov (United States)

Bloemsaat, Gijs; Van Galen, Gerard P; Meulenbroek, Ruud G J

2003-05-01

This study investigated the combined effects of orthographical irregularity and auditory memory load on the kinematics of finger movements in a transcription-typewriting task. Eight right-handed touch-typists were asked to type 80 strings of ten seven-letter words. In half the trials an irregularly spelt target word elicited a specific key press sequence of either the left or right index finger. In the other trials regularly spelt target words elicited the same key press sequence. An auditory memory load was added in half the trials by asking participants to remember the pitch of a tone during task performance. Orthographical irregularity was expected to slow down performance. Auditory memory load, viewed as a low level stressor, was expected to affect performance only when orthographically irregular words needed to be typed. The hypotheses were confirmed. Additional analysis showed differential effects on the left and right hand, possibly related to verbal-manual interference and hand dominance. The results are discussed in relation to relevant findings of recent neuroimaging studies.

Two media method for linear attenuation coefficient determination of irregular soil samples; Metodo dos dois meios para a determinacao do coeficiente de atenuacao linear de amostras irregulares de solos

Energy Technology Data Exchange (ETDEWEB)

Vici, Carlos Henrique Georges

2004-07-01

In several situations of nuclear applications, the knowledge of gamma-ray linear attenuation coefficient for irregular samples is necessary, such as in soil physics and geology. This work presents the validation of a methodology for the determination of the linear attenuation coefficient ({mu}) of irregular shape samples, in such a way that it is not necessary to know the thickness of the considered sample. With this methodology irregular soil samples (undeformed field samples) from Londrina region, north of Parana were studied. It was employed the two media method for the {mu} determination. It consists of the {mu} determination through the measurement of a gamma-ray beam attenuation by the sample sequentially immersed in two different media, with known and appropriately chosen attenuation coefficients. For comparison, the theoretical value of {mu} was calculated by the product of the mass attenuation coefficient, obtained by the WinXcom code, and the measured value of the density sample. This software employs the chemical composition of the samples and supplies a table of the mass attenuation coefficients versus the photon energy. To verify the validity of the two media method, compared with the simple gamma ray transmission method, regular pome stone samples were used. With these results for the attenuation coefficients and their respective deviations, it was possible to compare the two methods. In this way we concluded that the two media method is a good tool for the determination of the linear attenuation coefficient of irregular materials, particularly in the study of soils samples. (author)

The Withdrawal of Health Care from Irregular Immigrants and Medical Conscientious Objection

Directory of Open Access Journals (Sweden)

Yolanda Garcìa Ruiz

2016-12-01

Full Text Available The economic crisis so strongly affecting some southern European countries has led to significant cuts in the system of universal public health care in Spain. Such measures particularly affect irregular immigrants and can also cause significant public health consequences. A form of civil resistance that deserves to be analyzed is the conscientious objection of Spanish doctors who have chosen to continue attending irregular immigrants in contravention of new the rules restricting their access to the public health system and their right to health. The aim of this paper is to analyze the new regulation which cut health care for irregular immigrants in Spain, the impact of this new regulation on the most vulnerable groups, and the response of doctors, who exercised their right to conscientious objection in relation to applying the new regulation. Finally to examine the announcement of change which came about as a consequence of international and domestic social pressure causing political risk to the Spanish National Government. La crisis económica, que ha afectado tan profundamente a algunos países del sur de Europa, ha dado lugar a significativos recortes en el sistema de atención sanitaria pública en España. Algunas de las medidas adoptadas han afectado específicamente a los inmigrantes irregulares y pueden tener, incluso, efectos en el ámbito de la salud pública. Una forma de desobediencia civil que merece ser analizada es la declaración de objeción de conciencia de determinados médicos y profesionales sanitarios españoles que han continuado atendiendo a los inmigrantes irregulares en contra de las nuevas  restricciones impuestas por el Gobierno que afectan al reconocimiento universal del derecho a la salud. El propósito de este artículo es el de analizar la nueva regulación que limita el acceso a la asistencia sanitaria de los inmigrantes irregulares en España, el impacto de esta nueva regulación en los grupos más vulnerables

Prices and costs of irregularity in renewable resources in the liberalized electricity markets

International Nuclear Information System (INIS)

Menanteau, Ph.; Finon, D.

2004-01-01

The problems raised by incorporating irregular production are of a technical nature (risk of non-availability during peak demand, the requirements for additional reserves) but the electricity markets methods of operation impose economic penalties, which greatly exceed these additional technical costs. In this document, the authors examine the nature of the technical problems posed by irregularity of production and the additional costs resulting from this, and then analyse the origins of the economic penalties that the operation of liberalized electricity markets impose, taking in particular the example of the British market, the New Energy Trading Arrangement (NETA). It would appear that the markets' operating rules may conflict, in certain cases, with the targets for promoting electricity generation from renewable resources. Two types of solutions can therefore be envisaged: a set of rules to limit the impact on irregular production or collective handling of the adjustment to production from renewable resources as already exists in the Nordic electricity markets. (authors)

Structure evolution of gelatin particles induced by pH and ionic strength.

Science.gov (United States)

Xu, Jing; Li, Tianduo; Tao, Furong; Cui, Yuezhi; Xia, Yongmei

2013-03-01

Microstructure of gelatin particles played a key role in determining the physicochemical properties of gelatin. Ionic strength and pH as systematic manners were considered to affect gelatin particles structure on the micrometer scale. Scanning electron microscopy was used for depicting the morphologies of gelatin particles. Increasing pH to 10.0 or decreasing pH to 4.0, spherical, spindle, and irregular aggregates of gelatin particles at 2, 6, 10, and 14% solution (w/w) were all transformed to spindle aggregates. When NaCl was added to the system, the molecular chains of gelatin possibly rearranged themselves in a stretched state, and the ribbon aggregates was observed. The structural transitions of gelatin aggregates were strongly depended on the electrostatic repulsion. In the gelatin-sodium dodecyl sulfate (SDS) case, the micrometer scale of aggregates was larger and the different degrees of cross-links were induced through hydrophobic interaction and electrostatic repulsion. Copyright © 2012 Wiley Periodicals, Inc.

Non-storm irregular variation of the Dst index

Directory of Open Access Journals (Sweden)

S. Nakano

2012-01-01

Full Text Available The Dst index has a long-term variation that is not associated with magnetic storms. We estimated the long-term non-storm component of the Dst variation by removing the short-term variation related to magnetic storms. The results indicate that the variation of the non-storm component includes not only a seasonal variation but also an irregular variation. The irregular long-term variation is likely to be due to an anti-correlation with the long-term variation of solar-wind activity. In particular, a clear anti-correlation is observed between the non-storm component of Dst and the long-term variation of the solar-wind dynamic pressure. This means that in the long term, the Dst index tends to increase when the solar-wind dynamic pressure decreases. We interpret this anti-correlation as an indication that the long-term non-storm variation of Dst is influenced by the tail current variation. The long-term variation of the solar-wind dynamic pressure controls the plasma sheet thermal pressure, and the change of the plasma sheet thermal pressure would cause the non-storm tail current variation, resulting in the non-storm variation of Dst.

Irregular working hours and fatigue of cabin crew.

Science.gov (United States)

Castro, Marta; Carvalhais, José; Teles, Júlia

2015-01-01

Beyond workload and specific environmental factors, flight attendants can be exposed to irregular working hours, conflicting with their circadian rhythms and having a negative impact in sleep, fatigue, health, social and family life, and performance which is critical to both safety and security in flight operations. This study focuses on the irregular schedules of cabin crew as a trigger of fatigue symptoms in a wet lease Portuguese airline. The aim was to analyze: what are the requirements of the cabin crew work; whether the schedules being observed and effective resting timeouts are triggering factors of fatigue; and the existence of fatigue symptoms in the cabin crew. A questionnaire has been adapted and applied to a sample of 73 cabin crew-members (representing 61.9% of the population), 39 females and 34 males, with an average age of 27.68 ± 4.27 years. Our data indicate the presence of fatigue and corresponding health symptoms among the airline cabin crew, despite of the sample favorable characteristics. Senior workers and women are more affected. Countermeasures are required. Recommendations can be made regarding the fatigue risk management, including work organization, education and awareness training programmes and specific countermeasures.

Transformation-cost time-series method for analyzing irregularly sampled data.

Science.gov (United States)

Ozken, Ibrahim; Eroglu, Deniz; Stemler, Thomas; Marwan, Norbert; Bagci, G Baris; Kurths, Jürgen

2015-06-01

Irregular sampling of data sets is one of the challenges often encountered in time-series analysis, since traditional methods cannot be applied and the frequently used interpolation approach can corrupt the data and bias the subsequence analysis. Here we present the TrAnsformation-Cost Time-Series (TACTS) method, which allows us to analyze irregularly sampled data sets without degenerating the quality of the data set. Instead of using interpolation we consider time-series segments and determine how close they are to each other by determining the cost needed to transform one segment into the following one. Using a limited set of operations-with associated costs-to transform the time series segments, we determine a new time series, that is our transformation-cost time series. This cost time series is regularly sampled and can be analyzed using standard methods. While our main interest is the analysis of paleoclimate data, we develop our method using numerical examples like the logistic map and the Rössler oscillator. The numerical data allows us to test the stability of our method against noise and for different irregular samplings. In addition we provide guidance on how to choose the associated costs based on the time series at hand. The usefulness of the TACTS method is demonstrated using speleothem data from the Secret Cave in Borneo that is a good proxy for paleoclimatic variability in the monsoon activity around the maritime continent.

Transformation-cost time-series method for analyzing irregularly sampled data

Science.gov (United States)

Ozken, Ibrahim; Eroglu, Deniz; Stemler, Thomas; Marwan, Norbert; Bagci, G. Baris; Kurths, Jürgen

2015-06-01

Irregular sampling of data sets is one of the challenges often encountered in time-series analysis, since traditional methods cannot be applied and the frequently used interpolation approach can corrupt the data and bias the subsequence analysis. Here we present the TrAnsformation-Cost Time-Series (TACTS) method, which allows us to analyze irregularly sampled data sets without degenerating the quality of the data set. Instead of using interpolation we consider time-series segments and determine how close they are to each other by determining the cost needed to transform one segment into the following one. Using a limited set of operations—with associated costs—to transform the time series segments, we determine a new time series, that is our transformation-cost time series. This cost time series is regularly sampled and can be analyzed using standard methods. While our main interest is the analysis of paleoclimate data, we develop our method using numerical examples like the logistic map and the Rössler oscillator. The numerical data allows us to test the stability of our method against noise and for different irregular samplings. In addition we provide guidance on how to choose the associated costs based on the time series at hand. The usefulness of the TACTS method is demonstrated using speleothem data from the Secret Cave in Borneo that is a good proxy for paleoclimatic variability in the monsoon activity around the maritime continent.

Three-dimensional simulation and auto-stereoscopic 3D display of the battlefield environment based on the particle system algorithm

Science.gov (United States)

Ning, Jiwei; Sang, Xinzhu; Xing, Shujun; Cui, Huilong; Yan, Binbin; Yu, Chongxiu; Dou, Wenhua; Xiao, Liquan

2016-10-01

The army's combat training is very important now, and the simulation of the real battlefield environment is of great significance. Two-dimensional information has been unable to meet the demand at present. With the development of virtual reality technology, three-dimensional (3D) simulation of the battlefield environment is possible. In the simulation of 3D battlefield environment, in addition to the terrain, combat personnel and the combat tool ,the simulation of explosions, fire, smoke and other effects is also very important, since these effects can enhance senses of realism and immersion of the 3D scene. However, these special effects are irregular objects, which make it difficult to simulate with the general geometry. Therefore, the simulation of irregular objects is always a hot and difficult research topic in computer graphics. Here, the particle system algorithm is used for simulating irregular objects. We design the simulation of the explosion, fire, smoke based on the particle system and applied it to the battlefield 3D scene. Besides, the battlefield 3D scene simulation with the glasses-free 3D display is carried out with an algorithm based on GPU 4K super-multiview 3D video real-time transformation method. At the same time, with the human-computer interaction function, we ultimately realized glasses-free 3D display of the simulated more realistic and immersed 3D battlefield environment.

Similarity estimators for irregular and age uncertain time series

Science.gov (United States)

Rehfeld, K.; Kurths, J.

2013-09-01

Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many datasets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age uncertain time series. We compare the Gaussian-kernel based cross correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

Similarity estimators for irregular and age-uncertain time series

Science.gov (United States)

Rehfeld, K.; Kurths, J.

2014-01-01

Paleoclimate time series are often irregularly sampled and age uncertain, which is an important technical challenge to overcome for successful reconstruction of past climate variability and dynamics. Visual comparison and interpolation-based linear correlation approaches have been used to infer dependencies from such proxy time series. While the first is subjective, not measurable and not suitable for the comparison of many data sets at a time, the latter introduces interpolation bias, and both face difficulties if the underlying dependencies are nonlinear. In this paper we investigate similarity estimators that could be suitable for the quantitative investigation of dependencies in irregular and age-uncertain time series. We compare the Gaussian-kernel-based cross-correlation (gXCF, Rehfeld et al., 2011) and mutual information (gMI, Rehfeld et al., 2013) against their interpolation-based counterparts and the new event synchronization function (ESF). We test the efficiency of the methods in estimating coupling strength and coupling lag numerically, using ensembles of synthetic stalagmites with short, autocorrelated, linear and nonlinearly coupled proxy time series, and in the application to real stalagmite time series. In the linear test case, coupling strength increases are identified consistently for all estimators, while in the nonlinear test case the correlation-based approaches fail. The lag at which the time series are coupled is identified correctly as the maximum of the similarity functions in around 60-55% (in the linear case) to 53-42% (for the nonlinear processes) of the cases when the dating of the synthetic stalagmite is perfectly precise. If the age uncertainty increases beyond 5% of the time series length, however, the true coupling lag is not identified more often than the others for which the similarity function was estimated. Age uncertainty contributes up to half of the uncertainty in the similarity estimation process. Time series irregularity

Regular-, irregular-, and pseudo-character processing in Chinese: The regularity effect in normal adult readers

Directory of Open Access Journals (Sweden)

Dustin Kai Yan Lau

2014-03-01

Full Text Available Background Unlike alphabetic languages, Chinese uses a logographic script. However, the pronunciation of many character’s phonetic radical has the same pronunciation as the character as a whole. These are considered regular characters and can be read through a lexical non-semantic route (Weekes & Chen, 1999. Pseudocharacters are another way to study this non-semantic route. A pseudocharacter is the combination of existing semantic and phonetic radicals in their legal positions resulting in a non-existing character (Ho, Chan, Chung, Lee, & Tsang, 2007. Pseudocharacters can be pronounced by direct derivation from the sound of its phonetic radical. Conversely, if the pronunciation of a character does not follow that of the phonetic radical, it is considered as irregular and can only be correctly read through the lexical-semantic route. The aim of the current investigation was to examine reading aloud in normal adults. We hypothesized that the regularity effect, previously described for alphabetical scripts and acquired dyslexic patients of Chinese (Weekes & Chen, 1999; Wu, Liu, Sun, Chromik, & Zhang, 2014, would also be present in normal adult Chinese readers. Method Participants. Thirty (50% female native Hong Kong Cantonese speakers with a mean age of 19.6 years and a mean education of 12.9 years. Stimuli. Sixty regular-, 60 irregular-, and 60 pseudo-characters (with at least 75% of name agreement in Chinese were matched by initial phoneme, number of strokes and family size. Additionally, regular- and irregular-characters were matched by frequency (low and consistency. Procedure. Each participant was asked to read aloud the stimuli presented on a laptop using the DMDX software. The order of stimuli presentation was randomized. Data analysis. ANOVAs were carried out by participants and items with RTs and errors as dependent variables and type of stimuli (regular-, irregular- and pseudo-character as repeated measures (F1 or between subject�

Influence of the Wenchuan earthquake on self-reported irregular menstrual cycles in surviving women.

Science.gov (United States)

Li, Xiao-Hong; Qin, Lang; Hu, Han; Luo, Shan; Li, Lei; Fan, Wei; Xiao, Zhun; Li, Ying-Xing; Li, Shang-Wei

2011-09-01

To explore the influence of stress induced by the Wenchuan earthquake on the menstrual cycles of surviving women. Self-reports of the menstrual cycles of 473 women that survived the Wenchuan earthquake were analyzed. Menstrual regularity was defined as menses between 21 and 35 days long. The death of a child or the loss of property and social resources was verified for all surviving women. The severity of these losses was assessed and graded as high, little, and none. About 21% of the study participants reported that their menstrual cycles became irregular after the Wenchuan earthquake, and this percentage was significantly higher than before the earthquake (6%, p irregularity after the earthquake. Association analyses showed that some stressors of the Wenchuan earthquake were strongly associated with self-reports of menstrual irregularity, including the loss of children (RR: 1.58; 95% CI: 1.09, 2.28), large amounts of property (RR: 1.49; 95% CI: 1.03, 2.15), social resources (RR: 1.34; 95% CI: 1.00, 1.80) and the hormonal contraception use (RR: 1.62; 95% CI: 1.21, 1.83). Self-reported menstrual irregularity is common in women that survived the Wenchuan earthquake, especially in those who lost children, large amounts of property and social resources.

Backward particles in 4Hep reactions

International Nuclear Information System (INIS)

Glagolev, V.V.; Lebedev, R.M.; Pestova, G.D.; Shimansky, S.S.; Khairetdinov, K.U.; Sobczak, T.; Stepaniak, J.

1988-08-01

The invariant differential cross sections were investigated as functions of different backward particle momenta in 4 Hep interactions. Two data samples were used at the 4 He incident momenta 8.6 GeV/c and 13.6 GeV/c. The data were obtained by means of a 1-m hydrogen bubble chamber at Joint Institute for Nuclear Research Dubna. The spectra for nuclei showed a monotonous exponentially falling trend at both momenta. Some irregularities were observed in the nucleon and Π + spectra and these were especially visible at a lower beam momentum. The experimental data were satisfactorily reproduced by taking into account the Fermi motion and intermediate Δ-isobar states. (author). 7 figs., 2 tabs., 22 refs

VHF and UHF radar observations of equatorial F region ionospheric irregularities and background densities

Science.gov (United States)

Towle, D. M.

1980-02-01

A series of measurements of the properties of equatorial ionospheric irregularities were made at Kwajalein, Marshall Islands (M.I.) in August 1977 and July-August 1978. These measurements, sponsored by the Defense Nuclear Agency (DNA), involved coordinated ground-based and in situ sensors. The ARPA Long-Range Tracking and Instrumentation Radar (ALTAIR), operated by Lincoln Laboratory, obtained backscatter and transmission data during five nights in August 1977 and eight nights in July-August 1978. This report describes the ALTAIR data from the night of August 11, 1978, which yield direct quantitative measurements of 1-m and 3/8-m irregularities and of plasma depleted regions. These plasma depleted regions, previously predicted on the basis of theoretical analysis and in situ data, were observed during the decay phase and not the generative phase of the field-aligned irregularities.

Application of Response Surface Methodology for Optimization of Paracetamol Particles Formation by RESS Method

International Nuclear Information System (INIS)

Sabet, J.K.; Ghotbi, C.; Dorkoosh, F.

2012-01-01

Ultrafine particles of paracetamol were produced by Rapid Expansion of Supercritical Solution (RESS). The experiments were conducted to investigate the effects of extraction temperature (313-353 K), extraction pressure (10-18 MPa), pre expansion temperature (363-403 K), and post expansion temperature (273-323 K) on particles size and morphology of paracetamol particles. The characterization of the particles was determined by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and Liquid Chromatography/Mass Spectrometry (LC-MS) analysis. The average particle size of the original paracetamol was 20.8 μm, while the average particle size of paracetamol after nan onization via the RESS process was 0.46 μm depending on the experimental conditions used. Moreover, the morphology of the processed particles changed to spherical and regular while the virgin particles of paracetamol were needle-shape and irregular. Response surface methodology (RSM) was used to optimize the process parameters. The extraction temperature, 347 K; extraction pressure, 12 MPa; pre expansion temperature, 403?K; and post expansion temperature, 322 K was found to be the optimum conditions to achieve the minimum average particle size of paracetamol.

Runtime buffer management to improve the performance in irregular ...

Indian Academy of Sciences (India)

S¯adhan¯a Vol. 40, Part 4, June 2015, pp. 1117–1137. c Indian Academy of Sciences. Runtime buffer management to improve the performance in irregular Network-on-Chip architecture. UMAMAHESWARI S1,∗, MEGANATHAN D2 and. RAJA PAUL PERINBAM J3. 1Department of Information Technology, Anna University, ...

Exploring Hardware Support For Scaling Irregular Applications on Multi-node Multi-core Architectures

Energy Technology Data Exchange (ETDEWEB)

Secchi, Simone; Ceriani, Marco; Tumeo, Antonino; Villa, Oreste; Palermo, Gianluca; Raffo, Luigi

2013-06-05

With the recent emergence of large-scale knowledge dis- covery, data mining and social network analysis, irregular applications have gained renewed interest. Classic cache-based high-performance architectures do not provide optimal performances with such kind of workloads, mainly due to the very low spatial and temporal locality of the irregular control and memory access patterns. In this paper, we present a multi-node, multi-core, fine-grained multi-threaded shared-memory system architecture specifically designed for the execution of large-scale irregular applications, and built on top of three pillars, that we believe are fundamental to support these workloads. First, we offer transparent hardware support for Partitioned Global Address Space (PGAS) to provide a large globally-shared address space with no software library overhead. Second, we employ multi-threaded multi-core processing nodes to achieve the necessary latency tolerance required by accessing global memory, which potentially resides in a remote node. Finally, we devise hardware support for inter-thread synchronization on the whole global address space. We first model the performances by using an analytical model that takes into account the main architecture and application characteristics. We describe the hardware design of the proposed cus- tom architectural building blocks that provide support for the above- mentioned three pillars. Finally, we present a limited-scale evaluation of the system on a multi-board FPGA prototype with typical irregular kernels and benchmarks. The experimental evaluation demonstrates the architecture performance scalability for different configurations of the whole system.

The Himalia Satellite Group: A Case Study on the Dynamical Self-spreading of Families of Irregular Satellites and Asteroids

Science.gov (United States)

Li, Daohai; Christou, Apostolos A.

2015-11-01

Many of the outer planets' irregular satellites are grouped into families, thought to originate from collisional fragmentation (Nesvorný et al 2004, AJ). Interestingly, families associated with the largest irregulars are either more dispersed than expected (e.g. J6 Himalia; Nesvorný et al 2003, AJ), or do not exist at all (e.g. S9 Phoebe; Ćuk et al 2003, DDA meeting #34). Christou (2005, Icarus) found that gravitational scattering by Himalia of its own group could explain the large velocity dispersion found by Nesvorný et al (2003, AJ). At the same time, Christou identified a new type of dynamical mechanism that intermittently locks the node of the satellite J10 Lysithea to that of Himalia. The same mechanism, but due to Ceres, was recently found to operate within the Hoffmeister family, dispersing its members and allowing an estimate of its age (Novaković et al 2015, ApJ).Here we revisit the issue of family self-dispersion, aiming to better understand it by studying its effects on the Himalia group. For this we utilise (a) intensive test particle simulations on a larger scale than those by Christou (2005, Icarus) (b) a semi-analytical treatment of the new resonance based on the secular theory of coorbital motion by Namouni (1999, Icarus). This has allowed us to obtain firmer constraints on the rate of dispersion over time and on how the resonance affects the long-term evolution of the orbital elements. A principal result of this work is that particles near the resonance evolve differently than those away from it. During the meeting, we will present a new estimate of the family’s age as well as an analysis of the resonant structure and how it affects Himalia family members. We will also discuss the broader implications for the long-term evolution of orbital concentrations of small bodies in the solar system.Astronomical research at the Armagh Observatory is funded by the Northern Ireland Department of Culture, Arts and Leisure (DCAL).

The transition from regular to irregular motions, explained as travel on Riemann surfaces

International Nuclear Information System (INIS)

Calogero, F; Santini, P M; Gomez-Ullate, D; Sommacal, M

2005-01-01

We introduce and discuss a simple Hamiltonian dynamical system, interpretable as a three-body problem in the (complex) plane and providing the prototype of a mechanism explaining the transition from regular to irregular motions as travel on Riemann surfaces. The interest of this phenomenology-illustrating the onset in a deterministic context of irregular motions-is underlined by its generality, suggesting its eventual relevance to understand natural phenomena and experimental investigations. Here only some of our main findings are reported, without detailing their proofs: a more complete presentation will be published elsewhere

Questioning the Homogenization of Irregular Migrants in Educational Policy: From (Il)Legal Residence to Inclusive Education

Science.gov (United States)

Hemelsoet, Elias

2011-01-01

In this article Elias Hemelsoet questions the way irregular migrants are approached in educational policymaking. In most cases, estimations of the number of irregular migrants serve--despite large methodological problems--as a starting point for policymaking. Given the very diverse composition of this group of people, the question is whether…

Study of the spheronization process of glass particles by the gravitational falling process for internal selective radiotherapy

International Nuclear Information System (INIS)

Barros Filho, E.C.; Martinelli, J.R.; Sene, F.F.

2011-01-01

The internal selective radiotherapy is an alternative to treat hepatocellular carcinoma. Glass microspheres containing β - emitter radionuclide are introduced in the liver, and they are housed preferentially in the region where the cancer cells are located. The microspheres are trapped in the arterioles which feed the tumors, and the β - particles annihilate the cancer cells. The glass particles must be spherical to avoid unnecessary bleeding, and the particle size must be restricted to a range which optimizes the blocking effect and avoid the migration to other parts of the human body. The particle size distribution of microspheres is not easily predicted since the variation of the aspect ratio and the presence of agglomerates can influence the resulting particle size distribution. In the present work, the spheronization process to obtain microspheres from irregular shape glass particles with suitable diameter and shape for radiotherapy treatment is studied. (author)

Irregular migration and informal economy in Southern and Central-Eastern Europe: breaking the vicious cycle?

Science.gov (United States)

Maroukis, Thanos; Iglicka, Krystyna; Gmaj, Katarzyna

2011-01-01

The flexible and cheap labour that European “post-industrial” economies are in need of is often facilitated by undeclared labour. The undocumented migrant, from his/her part, relatively easily finds work that suits his -- at least initial -- plans. What lies behind this nexus between irregular migration and informal economy? To what extent can this nexus be attributed to the structural features of the so-called “secondary”, as opposed to “primary”, labour market? And how does migration policy correlate with this economic context and lead to the entrapment of migrants in irregularity? Finally, can this vicious cycle of interests and life-strategies be broken and what does the experience of the migrants indicate in this respect? This paper addresses these questions via an exploration of the grounds upon which irregular migration and the shadow economy complement each other in southern Europe (SE) and central and Eastern Europe (CEE) (two regions at different points in the migration cycle). In doing so, the dynamic character of the nexus between informal economy and irregular migration will come to the fore, and the abstract identity of the “average” undocumented migrant will be deconstructed.

Conflict management among irregular immigrants: the micro politics of intercultural respect.

OpenAIRE

Clough, Paul; Works in Progress Seminars Series

2010-01-01

A talk in the Works in Progress Seminars Series with the title of "Conflict management among irregular immigrants: the micro politics of intercultural respect". This talk is given by Prof Paul Clough.

Structure Irregularity Impedes Drop Roll-Off at Superhydrophobic Surfaces

DEFF Research Database (Denmark)

Larsen, Simon Tylsgaard; Andersen, Nis Korsgaard; Søgaard, Emil

2014-01-01

-off angles is found to be caused by a decrease of the receding contact angle, which in turn is caused by an increase of the triple phase contact line of the drops for those more irregular surfaces. To understand the observation, we propose to treat the microdrops as rigid bodies and apply a torque balance...

Colombia: la guerra irregular en el fin de siglo

Directory of Open Access Journals (Sweden)

Alfredo RANGEL SUÁREZ

2009-11-01

Full Text Available RESUMEN: El artículo analiza las transformaciones de la guerra irregular de las guerrillas colombianas en las últimas décadas. Para ello, se estudian los cambios que han afectado a distintos factores, como los objetivos estratégicos, los medios financieros, militares, las relaciones que mantienen con los partidos políticos tradicionales en el nivel local, sus parámetros ideológicos, el origen social de sus miembros. Con esta perspectiva, se analiza el cálculo político/temporal que la guerrilla hace en la actual coyuntura y sus consecuencias para el proceso de paz.ABSTRACT: This article examines the transformations of the irregular war of the colombian guerrillas, studying the changes of several factors such as the strategic goals, the financial and army resources, the relationship among the political parties in the local level, the evolution of their ideological parameters and of the social origin of their members. With this perspectiva, the author analyses temporal and political calculation that the guerrilla makes at this point, and its consequences for the peace process.

Designing Next Generation Massively Multithreaded Architectures for Irregular Applications

Energy Technology Data Exchange (ETDEWEB)

Tumeo, Antonino; Secchi, Simone; Villa, Oreste

2012-08-31

Irregular applications, such as data mining or graph-based computations, show unpredictable memory/network access patterns and control structures. Massively multi-threaded architectures with large node count, like the Cray XMT, have been shown to address their requirements better than commodity clusters. In this paper we present the approaches that we are currently pursuing to design future generations of these architectures. First, we introduce the Cray XMT and compare it to other multithreaded architectures. We then propose an evolution of the architecture, integrating multiple cores per node and next generation network interconnect. We advocate the use of hardware support for remote memory reference aggregation to optimize network utilization. For this evaluation we developed a highly parallel, custom simulation infrastructure for multi-threaded systems. Our simulator executes unmodified XMT binaries with very large datasets, capturing effects due to contention and hot-spotting, while predicting execution times with greater than 90% accuracy. We also discuss the FPGA prototyping approach that we are employing to study efficient support for irregular applications in next generation manycore processors.

Ice nucleation properties of mineral dust particles: determination of onset RHi, IN active fraction, nucleation time-lag, and the effect of active sites on contact angles

Directory of Open Access Journals (Sweden)

S. Dobbie

2010-01-01

Full Text Available A newly developed ice nucleation experimental set up was used to investigate the heterogeneous ice nucleation properties of three Saharan and one Spanish dust particle samples. It was observed that the spread in the onset relative humidities with respect to ice (RHi for Saharan dust particles varied from 104% to 110%, whereas for the Spanish dust from 106% to 110%. The elemental composition analysis shows a prominent Ca feature in the Spanish dust sample which could potentially explain the differences in nucleation threshold. Although the spread in the onset RHi for the three Saharan dust samples were in agreement, the active fractions and nucleation time-lags calculated at various temperature and RHi conditions were found to differ. This could be due to the subtle variation in the elemental composition of the dust samples, and surface irregularities like steps, cracks, cavities etc. A combination of classical nucleation theory and active site theory is used to understand the importance of these surface irregularities on the nucleability parameter, contact angle that is widely used in ice cloud modeling. These calculations show that the surface irregularities can reduce the contact angle by approximately 10 degrees.

Development of porous structure simulator for multi-scale simulation of irregular porous catalysts

International Nuclear Information System (INIS)

Koyama, Michihisa; Suzuki, Ai; Sahnoun, Riadh; Tsuboi, Hideyuki; Hatakeyama, Nozomu; Endou, Akira; Takaba, Hiromitsu; Kubo, Momoji; Del Carpio, Carlos A.; Miyamoto, Akira

2008-01-01

Efficient development of highly functional porous materials, used as catalysts in the automobile industry, demands a meticulous knowledge of the nano-scale interface at the electronic and atomistic scale. However, it is often difficult to correlate the microscopic interfacial interactions with macroscopic characteristics of the materials; for instance, the interaction between a precious metal and its support oxide with long-term sintering properties of the catalyst. Multi-scale computational chemistry approaches can contribute to bridge the gap between micro- and macroscopic characteristics of these materials; however this type of multi-scale simulations has been difficult to apply especially to porous materials. To overcome this problem, we have developed a novel mesoscopic approach based on a porous structure simulator. This simulator can construct automatically irregular porous structures on a computer, enabling simulations with complex meso-scale structures. Moreover, in this work we have developed a new method to simulate long-term sintering properties of metal particles on porous catalysts. Finally, we have applied the method to the simulation of sintering properties of Pt on alumina support. This newly developed method has enabled us to propose a multi-scale simulation approach for porous catalysts

Computing proton dose to irregularly moving targets

International Nuclear Information System (INIS)

Phillips, Justin; Gueorguiev, Gueorgui; Grassberger, Clemens; Dowdell, Stephen; Paganetti, Harald; Sharp, Gregory C; Shackleford, James A

2014-01-01

Purpose: While four-dimensional computed tomography (4DCT) and deformable registration can be used to assess the dose delivered to regularly moving targets, there are few methods available for irregularly moving targets. 4DCT captures an idealized waveform, but human respiration during treatment is characterized by gradual baseline shifts and other deviations from a periodic signal. This paper describes a method for computing the dose delivered to irregularly moving targets based on 1D or 3D waveforms captured at the time of delivery. Methods: The procedure uses CT or 4DCT images for dose calculation, and 1D or 3D respiratory waveforms of the target position at time of delivery. Dose volumes are converted from their Cartesian geometry into a beam-specific radiological depth space, parameterized in 2D by the beam aperture, and longitudinally by the radiological depth. In this new frame of reference, the proton doses are translated according to the motion found in the 1D or 3D trajectory. These translated dose volumes are weighted and summed, then transformed back into Cartesian space, yielding an estimate of the dose that includes the effect of the measured breathing motion. The method was validated using a synthetic lung phantom and a single representative patient CT. Simulated 4DCT was generated for the phantom with 2 cm peak-to-peak motion. Results: A passively-scattered proton treatment plan was generated using 6 mm and 5 mm smearing for the phantom and patient plans, respectively. The method was tested without motion, and with two simulated breathing signals: a 2 cm amplitude sinusoid, and a 2 cm amplitude sinusoid with 3 cm linear drift in the phantom. The tumor positions were equally weighted for the patient calculation. Motion-corrected dose was computed based on the mid-ventilation CT image in the phantom and the peak exhale position in the patient. Gamma evaluation was 97.8% without motion, 95.7% for 2 cm sinusoidal motion, 95.7% with 3 cm drift in

Irregular or absent periods--what can an ultrasound scan tell you?

Science.gov (United States)

Khalid, Asma

2004-02-01

Transvaginal ultrasonography has increased our appreciation of the physiological changes in the ovary and endometrium that occur during the normal menstrual cycle. It has become a primary investigative tool in women with irregular or absent periods. Its usefulness in cases of primary amenorrhoea to assess anatomy is also undisputed although it may have limitations in terms of its specificity. However, the interpretation of ultrasound images in women with irregular menses or secondary amenorrhoea is not entirely straightforward. This is particularly true in the diagnosis of polycystic ovary syndrome, a condition of uncertain aetiology, which may present with oligoamenorrhoea. This chapter aims to discuss the benefits and limitations of ultrasound while taking into account the broad overlap between normal and abnormal physiology, some of which has still to be elucidated.

Application of Wuhan Ionospheric Oblique Backscattering Sounding System (WIOBSS) for the investigation of midlatitude ionospheric irregularities

Science.gov (United States)

Wang, Jin; Zhou, Xiaoming; Qiao, Lei; Gong, Wanlin

2018-03-01

An upgrade of Wuhan Ionospheric Backscattering Sounding System (WIOBSS) was developed in 2015. Based on the Universal Serial Bus (USB), and a high performance FPGA, the newly designed WIOBSS has a completely digital structure, which makes it portable and flexible. Two identical WIOBSSs, which were situated at Mile (24.31°N, 103.39°E) and Puer (22.74°N, 101.05°E) respectively, were used to investigate the ionospheric irregularities. The comparisons of group distance, Doppler shift and width between Mile-Puer and Puer-Mile VHF ionospheric propagation paths indicate that the reciprocity of the irregularities is satisfied at midlatitude region. The WIOBSS is robust in the detection of ionospheric irregularities.

On the areas of various bodies in the Euclidean space: The case of irregular convex polygons

International Nuclear Information System (INIS)

Ozoemena, P.C.

1988-11-01

A theorem is proposed for the areas of n-sided irregular convex polygons, of given length of sides. The theorem is illustrated as a simple but powerful one in estimating the areas of irregular polygons, being dependent only on the number of sides n (and not on any of the explicit angles) of the irregular polygon. Finally, because of the global symmetry shown by equilateral triangles, squares and circles under group (gauge) theory, the relationships governing their areas, when they are inscribed or escribed in one another are discussed as riders, and some areas of their applications in graph theory, ratios and maxima and minima problems of differential calculus briefly mentioned. (author). 11 refs, 6 figs, 1 tab

Locating irregularly shaped clusters of infection intensity

DEFF Research Database (Denmark)

Yiannakoulias, Niko; Wilson, Shona; Kariuki, H. Curtis

2010-01-01

of infection intensity identifies two small areas within the study region in which infection intensity is elevated, possibly due to local features of the physical or social environment. Collectively, our results show that the "greedy growth scan" is a suitable method for exploratory geographical analysis...... for cluster detection. Real data are based on samples of hookworm and S. mansoni from Kitengei, Makueni district, Kenya. Our analysis of simulated data shows how methods able to find irregular shapes are more likely to identify clusters along rivers than methods constrained to fixed geometries. Our analysis...

First stellar abundances in the dwarf irregular galaxy Sextans A

NARCIS (Netherlands)

Kaufer, A; Venn, KA; Tolstoy, E; Pinte, C; Kudritzki, RP

We present the abundance analyses of three isolated A-type supergiant stars in the dwarf irregular galaxy Sextans A (= DDO 75) from high-resolution spectra obtained with the Ultraviolet-Visual Echelle Spectrograph (UVES) on the Kueyen telescope (UT2) of the ESO Very Large Telescope (VLT). Detailed

An irregular grid approach for pricing high-dimensional American options

NARCIS (Netherlands)

Berridge, S.J.; Schumacher, J.M.

2008-01-01

We propose and test a new method for pricing American options in a high-dimensional setting. The method is centered around the approximation of the associated complementarity problem on an irregular grid. We approximate the partial differential operator on this grid by appealing to the SDE

Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

NARCIS (Netherlands)

Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

2008-01-01

Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of

An Irregular Grid Approach for Pricing High-Dimensional American Options

NARCIS (Netherlands)

Berridge, S.J.; Schumacher, J.M.

2004-01-01

We propose and test a new method for pricing American options in a high-dimensional setting.The method is centred around the approximation of the associated complementarity problem on an irregular grid.We approximate the partial differential operator on this grid by appealing to the SDE

The influence of rail surface irregularities on contact forces and local stresses

Science.gov (United States)

Andersson, Robin; Torstensson, Peter T.; Kabo, Elena; Larsson, Fredrik

2015-01-01

The effect of initial rail surface irregularities on promoting further surface degradation is investigated. The study concerns rolling contact fatigue formation, in particular in the form of the so-called squats. The impact of surface irregularities in the form of dimples is quantified by peak magnitudes of dynamic contact stresses and contact forces. To this end simulations of two-dimensional (later extended to three-dimensional) vertical dynamic vehicle-track interaction are employed. The most influencing parameters are identified. It is shown that even very shallow dimples might have a large impact on local contact stresses. Peak magnitudes of contact forces and stresses due to the influence of rail dimples are shown to exceed those due to rail corrugation.

Menstrual irregularity and poly cystic ovarian syndrome among adolescent girls--a 2 year follow-up study.

Science.gov (United States)

Nair, M K C; Pappachan, Princly; Balakrishnan, Sheila; Leena, M L; George, Babu; Russell, Paul S

2012-01-01

To study the clinical outcome after a gap of 2 years, among adolescent girls with confirmed menstrual irregularity and with or without ultrasound diagnosed polycystic ovaries. 136 adolescent girls from a cohort of 301 girls between 15 and 17 years of age with confirmed menstrual irregularity, with or without ultrasound diagnosed polycystic ovaries, were assessed in detail after a gap of 2 years. Present menstrual history and symptoms as well as signs of polycystic ovary syndrome (PCOS) were recorded, apart from ultrasound scanning of abdomen. PCOS was diagnosed using Rotterdam's consensus criteria and a comparative analysis was done among cases with and without PCOS. In the phase-II study done after a gap of 2 years, there was a statistically significant lower percentage of irregularities in menses, acne and enlarged thyroid, but a statistically significant increase in hirsuitism as compared to Phase-I study. Of the 136 cases reported, 36.0% cases were found to have PCOS and 63.9% cases were normal. Comparison of the two groups showed a statistically significant higher percentage difference in prevalence of irregular menses (59.9%), hirsuitism (56.3%), acne (17.8%), obesity (17.3%), polycystic ovaries on ultrasound (47.8%) and clinical hyperandrogenism (56.1%) among those with PCOS as against those without PCOS. The results of this study support screening for menstrual irregularity, obesity and signs of clinical hyperandrogenism for early diagnosis of PCOS in an effort to improve the reproductive health of adolescent girls.

Effects of Turbulence on Settling Velocities of Synthetic and Natural Particles

Science.gov (United States)

Jacobs, C.; Jendrassak, M.; Gurka, R.; Hackett, E. E.

2014-12-01

For large-scale sediment transport predictions, an important parameter is the settling or terminal velocity of particles because it plays a key role in determining the concentration of sediment particles within the water column as well as the deposition rate of particles onto the seabed. The settling velocity of particles is influenced by the fluid dynamic environment as well as attributes of the particle, such as its size, shape, and density. This laboratory study examines the effects of turbulence, generated by an oscillating grid, on both synthetic and natural particles for a range of flow conditions. Because synthetic particles are spherical, they serve as a reference for the natural particles that are irregular in shape. Particle image velocimetry (PIV) and high-speed imaging systems were used simultaneously to study the interaction between the fluid mechanics and sediment particles' dynamics in a tank. The particles' dynamics were analyzed using a custom two-dimensional tracking algorithm used to obtain distributions of the particle's velocity and acceleration. Turbulence properties, such as root-mean-square turbulent velocity and vorticity, were calculated from the PIV data. Results are classified by Stokes number, which was based-on the integral scale deduced from the auto-correlation function of velocity. We find particles with large Stokes numbers are unaffected by the turbulence, while particles with small Stokes numbers primarily show an increase in settling velocity in comparison to stagnant flow. The results also show an inverse relationship between Stokes number and standard deviation of the settling velocity. This research enables a better understanding of the interdependence between particles and turbulent flow, which can be used to improve parameterizations in large-scale sediment transport models.

New bounds on axionlike particles from the Fermi Large Area Telescope observation of PKS 2155 -304

Science.gov (United States)

Zhang, Cun; Liang, Yun-Feng; Li, Shang; Liao, Neng-Hui; Feng, Lei; Yuan, Qiang; Fan, Yi-Zhong; Ren, Zhong-Zhou

2018-03-01

The axionlike particle (ALP)-photon mixing in the magnetic field around γ -ray sources or along the line of sight could induce oscillation between photons and ALPs, which then causes irregularities in the γ -ray spectra. In this work we search for such spectral irregularities in the spectrum of PKS 2155 -304 using 8.6 years of data from the Fermi Large Area Telescope (Fermi-LAT). No significant evidence for the presence of ALP-photon oscillation is obtained, and the parameter space of ALPs is constrained. The exclusion region sensitively depends on the poorly known magnetic field of the host galaxy cluster of PKS 2155 -304 . If the magnetic field is as high as ˜10 μ G , the "holelike" parameter region allowed in Ref. [1] can be ruled out.

The relationship between premenstrual symptoms, menstrual pain, irregular menstrual cycles, and psychosocial stress among Japanese college students.

Science.gov (United States)

Yamamoto, Kazuhiko; Okazaki, Ai; Sakamoto, Yoko; Funatsu, Michiko

2009-01-01

The aim of this study was to examine the relationship between menses-associated health problems of women, such as premenstrual symptoms, menstrual pain and irregular menstrual cycles, and psychosocial stress. A cross-sectional study was conducted among Japanese college students, measuring psychosocial stress levels by means of IMPS (The Inventory to Measure Psychosocial Stress). A total of 264 female students (mean age 19.4 years), who were invited to participate in the study in October 2007, completed the questionnaire, which dealt with anthropometric data, lifestyle, menstrual history, and menstrual health status. Forty-three students were excluded due to missing data, and the remaining 221 were analyzed. The proportions of students who reported premenstrual symptoms, menstrual pain, and the experience of irregular menstrual cycles were 79%, 79%, and 63%, respectively. Students who reported premenstrual symptoms, menstrual pain, and the experience of irregular menstrual cycles had higher stress scores than those who did not. Multiple logistic regression analyses were used to identify independent factors associated with having premenstrual symptoms, menstrual pain, and the experience of irregular menstrual cycles. Stress score, heavy menstrual flow, and menstrual pain were significant predictors for premenstrual symptoms, while age at menarche and having premenstrual symptoms were significant predictors for menstrual pain. Both stress score and body mass index were found to be significant predictors for having experienced irregular menstrual cycles. The results suggest that psychosocial stress is independently associated with premenstrual symptoms and the experience of irregular menstrual cycles among college students, implying that changes in the functional potentiality of women as a result of stress are related with changes in their menstrual function.

A novel method of the image processing on irregular triangular meshes

Science.gov (United States)

Vishnyakov, Sergey; Pekhterev, Vitaliy; Sokolova, Elizaveta

2018-04-01

The paper describes a novel method of the image processing based on irregular triangular meshes implementation. The triangular mesh is adaptive to the image content, least mean square linear approximation is proposed for the basic interpolation within the triangle. It is proposed to use triangular numbers to simplify using of the local (barycentric) coordinates for the further analysis - triangular element of the initial irregular mesh is to be represented through the set of the four equilateral triangles. This allows to use fast and simple pixels indexing in local coordinates, e.g. "for" or "while" loops for access to the pixels. Moreover, representation proposed allows to use discrete cosine transform of the simple "rectangular" symmetric form without additional pixels reordering (as it is used for shape-adaptive DCT forms). Furthermore, this approach leads to the simple form of the wavelet transform on triangular mesh. The results of the method application are presented. It is shown that advantage of the method proposed is a combination of the flexibility of the image-adaptive irregular meshes with the simple form of the pixel indexing in local triangular coordinates and the using of the common forms of the discrete transforms for triangular meshes. Method described is proposed for the image compression, pattern recognition, image quality improvement, image search and indexing. It also may be used as a part of video coding (intra-frame or inter-frame coding, motion detection).

Effect of surface stress and irregularity of the interface on the ...

Indian Academy of Sciences (India)

Surface stress; irregularity of the interface; magneto-elastic crustal ... stress plays a vital role in the propagation of waves due to the fact that the surface of a ...... Mumbai, for his computational help towards the numerical calculations and graphs.

The Biosynthetic Origin of Irregular Monoterpenes in Lavandula

Science.gov (United States)

Demissie, Zerihun A.; Erland, Lauren A. E.; Rheault, Mark R.; Mahmoud, Soheil S.

2013-01-01

Lavender essential oils are constituted predominantly of regular monoterpenes, for example linalool, 1,8-cineole, and camphor. However, they also contain irregular monoterpenes including lavandulol and lavandulyl acetate. Although the majority of genes responsible for the production of regular monoterpenes in lavenders are now known, enzymes (including lavandulyl diphosphate synthase (LPPS)) catalyzing the biosynthesis of irregular monoterpenes in these plants have not been described. Here, we report the isolation and functional characterization of a novel cis-prenyl diphosphate synthase cDNA, termed Lavandula x intermedia lavandulyl diphosphate synthase (LiLPPS), through a homology-based cloning strategy. The LiLPPS ORF, encoding for a 305-amino acid long protein, was expressed in Escherichia coli, and the recombinant protein was purified by nickel-nitrilotriacetic acid affinity chromatography. The approximately 34.5-kDa bacterially produced protein specifically catalyzed the head-to-middle condensation of two dimethylallyl diphosphate units to LPP in vitro with apparent Km and kcat values of 208 ± 12 μm and 0.1 s−1, respectively. LiLPPS is a homodimeric enzyme with a sigmoidal saturation curve and Hill coefficient of 2.7, suggesting a positive co-operative interaction among its catalytic sites. LiLPPS could be used to modulate the production of lavandulol and its derivatives in plants through metabolic engineering. PMID:23306202

Frequency and irregularity of heart rate in drivers suspected of driving under the influence of cannabis.

Science.gov (United States)

Khiabani, Hassan Z; Mørland, Jørg; Bramness, Jørgen G

2008-12-01

Delta 9-tetrahydrocannabinol (THC) is the major active component of cannabis. Cardiovascular effects of THC have previously been reported: tachycardia after intake, but also bradycardia at higher doses. The purpose of this study was, firstly, to investigate the frequency and irregularity of heart rate in a group of cannabis users in their natural surroundings. We also compared THC-positive drivers with a regular pulse with THC-positive drivers with an irregular pulse. The division of Forensic Toxicology and Drug Abuse (DFTDA) at the Norwegian Institute of Public Heath analyzes blood samples from all drivers suspected of driving under the influence of drugs. We studied pulse rate and regularity in 502 THC-positive drivers who tested negative for other substances. As a control group, we randomly selected 125 drug-negative cases from the database of the DFTDA; no alcohol, narcotics, or medicinal drugs of abuse were detected. The Delta9-THC-positive drivers had a higher mean pulse rate than the control group [82.8 beats/min (SD 16.3) versus 75.6 beats/min (SD 9.2)] and more cases with tachycardia were detected in the Delta9-THC-positive group (19.4% versus 1.6%). There was only one driver with an irregular heart beat in the control group, while there were nine among the Delta9-THC-positive drivers. The drivers with an irregular pulse were over-represented amongst those with the lowest blood Delta9-THC concentrations. This report represents a large study of subjects in a real-life situation and includes observations on pulse frequency, regularity, and blood Delta9-THC concentration. A substantial fraction of Delta9-THC-positive drivers had tachycardia, but there was no correlation between blood Delta9-THC concentration and pulse rate in the present study. We had no further diagnostic information on the cause of the pulse irregularities, but our results indicate that occasional users of cannabis tend to have irregular heart rates at low THC concentrations and at low

Analysis of Mid-Latitude Plasma Density Irregularities in the Presence of Finite Larmor Radius Effects

Science.gov (United States)

Sotnikov, V. I.; Kim, T. C.; Mishin, E. V.; Kil, H.; Kwak, Y. S.; Paraschiv, I.

2017-12-01

Ionospheric irregularities cause scintillations of electromagnetic signals that can severely affect navigation and transionospheric communication, in particular during space storms. At mid-latitudes the source of F-region Field Aligned Irregularities (FAI) is yet to be determined. They can be created in enhanced subauroral flow channels (SAI/SUBS), where strong gradients of electric field, density and plasma temperature are present. Another important source of FAI is connected with Medium-scale travelling ionospheric disturbances (MSTIDs). Related shear flows and plasma density troughs point to interchange and Kelvin-Helmholtz type instabilities as a possible source of plasma irregularities. A model of nonlinear development of these instabilities based on the two-fluid hydrodynamic description with inclusion of finite Larmor radius effects will be presented. This approach allows to resolve density irregularities on the meter scale. A numerical code in C language to solve the derived nonlinear equations for analysis of interchange and flow velocity shear instabilities in the ionosphere was developed. This code will be used to analyze competition between interchange and Kelvin-Helmholtz instabilities in the mid-latitude region. The high-resolution simulations with continuous density and velocity profiles will be driven by the ambient conditions corresponding to the in situ data obtained during the 2016 Daejeon (Korea) and MU (Japan) radar campaign and data collected simultaneously by the Swarm satellites passed over Korea and Japan. PA approved #: 88ABW-2017-3641

Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

Directory of Open Access Journals (Sweden)

Pablo Zuluaga-Ramírez

2015-11-01

Full Text Available This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL and realistic variable amplitude loads (VAL, representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications.

Surface Irregularity Factor as a Parameter to Evaluate the Fatigue Damage State of CFRP

Science.gov (United States)

Zuluaga-Ramírez, Pablo; Frövel, Malte; Belenguer, Tomás; Salazar, Félix

2015-01-01

This work presents an optical non-contact technique to evaluate the fatigue damage state of CFRP structures measuring the irregularity factor of the surface. This factor includes information about surface topology and can be measured easily on field, by techniques such as optical perfilometers. The surface irregularity factor has been correlated with stiffness degradation, which is a well-accepted parameter for the evaluation of the fatigue damage state of composite materials. Constant amplitude fatigue loads (CAL) and realistic variable amplitude loads (VAL), representative of real in- flight conditions, have been applied to “dog bone” shaped tensile specimens. It has been shown that the measurement of the surface irregularity parameters can be applied to evaluate the damage state of a structure, and that it is independent of the type of fatigue load that has caused the damage. As a result, this measurement technique is applicable for a wide range of inspections of composite material structures, from pressurized tanks with constant amplitude loads, to variable amplitude loaded aeronautical structures such as wings and empennages, up to automotive and other industrial applications. PMID:28793655

Ovarian markers and irregular menses among women with type 1 diabetes in the Epidemiology of Diabetes Interventions and Complications study.

Science.gov (United States)

Kim, C; Miller, R S; Braffett, B H; Pan, Y; Arends, V L; Saenger, A K; Barnie, A; Sarma, A V

2018-03-01

Women with type 1 diabetes have increased risk of infertility compared to women without diabetes even after adjustment for irregular menses, but aetiologies are incompletely understood. Our aim was to examine the prevalence of abnormalities in ovarian markers consistent with polycystic ovary syndrome in women with type 1 diabetes and associations with irregular menses and diabetes-specific variables. We conducted a secondary analysis of women in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study (DCCT/EDIC), a randomized trial and observational follow-up of intensive insulin therapy for type 1 diabetes. We included women with anti-Müllerian hormone (AMH) measurements among women not using oral contraceptives (n = 187). Initial AMH and testosterone measures were performed between EDIC years 1 and 4. History of irregular menses was assessed annually. The median age of women was 35 (interquartile ratio 29, 40) years; 133 (35%) had elevated AMH and 62 (17%) reported irregular menses. Twelve per cent of women had relative elevations in total testosterone. In multivariable models, lower insulin dosages were associated with higher AMH concentrations (P = .0027), but not diabetes duration, glycemic control, body mass index or irregular menses. Neither irregular menses nor diabetes-specific variables were associated with testosterone concentrations. Among women with type 1 diabetes in their thirties, abnormalities in ovarian markers are common and not associated with irregular menses and thus may partially account for decreased fecundity in women with type 1 diabetes. © 2018 John Wiley & Sons Ltd.

Model tracking dual stochastic controller design under irregular internal noises

International Nuclear Information System (INIS)

Lee, Jong Bok; Heo, Hoon; Cho, Yun Hyun; Ji, Tae Young

2006-01-01

Although many methods about the control of irregular external noise have been introduced and implemented, it is still necessary to design a controller that will be more effective and efficient methods to exclude for various noises. Accumulation of errors due to model tracking, internal noises (thermal noise, shot noise and l/f noise) that come from elements such as resistor, diode and transistor etc. in the circuit system and numerical errors due to digital process often destabilize the system and reduce the system performance. New stochastic controller is adopted to remove those noises using conventional controller simultaneously. Design method of a model tracking dual controller is proposed to improve the stability of system while removing external and internal noises. In the study, design process of the model tracking dual stochastic controller is introduced that improves system performance and guarantees robustness under irregular internal noises which can be created internally. The model tracking dual stochastic controller utilizing F-P-K stochastic control technique developed earlier is implemented to reveal its performance via simulation

Automated image analysis of atomic force microscopy images of rotavirus particles

International Nuclear Information System (INIS)

Venkataraman, S.; Allison, D.P.; Qi, H.; Morrell-Falvey, J.L.; Kallewaard, N.L.; Crowe, J.E.; Doktycz, M.J.

2006-01-01

A variety of biological samples can be imaged by the atomic force microscope (AFM) under environments that range from vacuum to ambient to liquid. Generally imaging is pursued to evaluate structural features of the sample or perhaps identify some structural changes in the sample that are induced by the investigator. In many cases, AFM images of sample features and induced structural changes are interpreted in general qualitative terms such as markedly smaller or larger, rougher, highly irregular, or smooth. Various manual tools can be used to analyze images and extract more quantitative data, but this is usually a cumbersome process. To facilitate quantitative AFM imaging, automated image analysis routines are being developed. Viral particles imaged in water were used as a test case to develop an algorithm that automatically extracts average dimensional information from a large set of individual particles. The extracted information allows statistical analyses of the dimensional characteristics of the particles and facilitates interpretation related to the binding of the particles to the surface. This algorithm is being extended for analysis of other biological samples and physical objects that are imaged by AFM

Automated image analysis of atomic force microscopy images of rotavirus particles

Energy Technology Data Exchange (ETDEWEB)

Venkataraman, S. [Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Electrical and Computer Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Allison, D.P. [Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Biochemistry, Cellular, and Molecular Biology, University of Tennessee, Knoxville, TN 37996 (United States); Molecular Imaging Inc. Tempe, AZ, 85282 (United States); Qi, H. [Department of Electrical and Computer Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Morrell-Falvey, J.L. [Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Kallewaard, N.L. [Vanderbilt University Medical Center, Nashville, TN 37232-2905 (United States); Crowe, J.E. [Vanderbilt University Medical Center, Nashville, TN 37232-2905 (United States); Doktycz, M.J. [Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)]. E-mail: doktyczmj@ornl.gov

2006-06-15

A variety of biological samples can be imaged by the atomic force microscope (AFM) under environments that range from vacuum to ambient to liquid. Generally imaging is pursued to evaluate structural features of the sample or perhaps identify some structural changes in the sample that are induced by the investigator. In many cases, AFM images of sample features and induced structural changes are interpreted in general qualitative terms such as markedly smaller or larger, rougher, highly irregular, or smooth. Various manual tools can be used to analyze images and extract more quantitative data, but this is usually a cumbersome process. To facilitate quantitative AFM imaging, automated image analysis routines are being developed. Viral particles imaged in water were used as a test case to develop an algorithm that automatically extracts average dimensional information from a large set of individual particles. The extracted information allows statistical analyses of the dimensional characteristics of the particles and facilitates interpretation related to the binding of the particles to the surface. This algorithm is being extended for analysis of other biological samples and physical objects that are imaged by AFM.

Videokymography. Imaging and quantification of regular and irregular vocal fold vibrations

NARCIS (Netherlands)

Schutte, HK; Svec, JG; Sram, F; McCafferty, G; Coman, W; Carroll, R

1996-01-01

A newly developed imaging technique makes it possible to observe the vocal fold vibration pattern also under unstable conditions. In contrast to stroboscopy, which strongly relies on the regularity of the vibration under study videokymography enables the study of irregular patterns as well. The

Health care for irregular migrants: pragmatism across Europe: a qualitative study

NARCIS (Netherlands)

Dauvrin, M.; Lorant, V.; Sandhu, S.; Devillé, W.; Dia, H.; Dias, S.; Gaddini, A.; Ioannidis, E.; Jensen, N.K.; Kluge, U.; Mertaniemi, R.; Puigpinós i Riera, R.; Sárváry, A.; Straßmayr, C.; Stankunas, M.; Soares, J.J.F.; Welbel, M.; Priebe, S.

2012-01-01

Background Health services in Europe face the challenge of delivering care to a heterogeneous group of irregular migrants (IM). There is little empirical evidence on how health professionals cope with this challenge. This study explores the experiences of health professionals providing care to IM in

Meal irregularity and cardiometabolic consequences: results from observational and intervention studies

NARCIS (Netherlands)

Pot, G.K.; Almoosawi, S; Stephen, AM

2016-01-01

Studying irregular meal patterns fits in with the latest research focusing not only on what people eat but also when they eat, also called chrono-nutrition. Chrono-nutrition involves studying the impact of nutrition on metabolism via circadian patterns, including three aspects of time:

Conflict Without Casualties: Non-Lethal Weapons in Irregular Warfare

Science.gov (United States)

2007-09-01

the body,” and the Geneva Protocol of 1925, bans the use of chemical and biological weapons .11 On 8 April 1975, President Ford issued Executive...E Funding – PE 63851M) (accessed 15 December 2006). The American Journal of Bioethics . “Medical Ethics and Non-Lethal Weapons .” Bioethics.net...CASUALTIES: NON-LETHAL WEAPONS IN IRREGULAR WARFARE by Richard L. Scott September 2007 Thesis Advisor: Robert McNab Second Reader

The normal squamocolumnar junction is circumferentially even and minimal irregularities are manifestations of gastroesophageal acid reflux.

Science.gov (United States)

Guerrero Garcia Hall, Mats; Wenner, Jörgen; Öberg, Stefan

2017-03-01

The macroscopic appearance of the normal squamocolumnar junction (SCJ) is often described as serrated with short projections of columnar mucosa that extend into the esophagus. As studies of the normal SCJ are sparse, the aim of this study was to test the hypothesis that the normal SCJ is even and that irregularities are manifestations of acid reflux. Fifty asymptomatic subjects and 149 patients with symptoms suggestive of gastroesophageal reflux disease underwent endoscopy and 48-h pH monitoring with a pH electrode positioned immediately above the SCJ. The shape of the SCJ was assessed according to the Z-line appearance classification and correlated with clinical characteristics and the degree of esophageal acid exposure in the most distal esophagus. Even SCJs without irregularities were significantly more common in asymptomatic subjects compared with patients (50% versus 10%, p acid exposure in individuals with an even SCJ was within normal limits. With increasing degree of irregularity of the SCJ, the frequency and duration of reflux episodes, the degree of distal esophageal acid exposure, and the prevalence of abnormal acid exposure increased progressively and significantly. The shape of the normal SCJ is even and also minimal irregularities are a consequence of acid reflux, likely due to the formation of small areas of metaplastic columnar mucosa.

Comparative study of the performance of columns packed with several new fine silica particles. Would the external roughness of the particles affect column properties?

Science.gov (United States)

Gritti, Fabrice; Guiochon, Georges

2007-09-28

We measured and compared the characteristics and performance of columns packed with particles of five different C(18)-bonded silica, 3 and 5 microm Luna, 3 microm Atlantis, 3.5 microm Zorbax, and 2.7 microm Halo. The average particle size of each material was derived from the SEM pictures of 200 individual particles. These pictures contrast the irregular morphology of the external surface of the Zorbax and Halo particles and the smooth surface of the Luna and Atlantis particles. In a wide range of mobile phase velocities (from 0.010 to 3 mL/min) and at ambient temperature, we measured the first and second central moments of the peaks of naphthalene, insulin, and bovine serum albumin (BSA). These moments were corrected for the contributions of the extra-column volumes to calculate the reduced HETPs. The C-terms of naphthalene and insulin are largest for the Halo and Zorbax materials and the A-term smallest for the Halo-packed column. The Halo column performs the best for the low molecular weight compound naphthalene (minimum reduced HETP, 1.4) but is not as good as the Atlantis or Luna columns for the large molecular weight compound insulin. The Zorbax column is the least efficient column because of its large C-term. The lowest sample diffusivity through these particles, alone, does not account for the results. It is most likely that the roughness of the external surface of the Halo and Zorbax particles limit the performance of these columns at high flow rates generating an unusually high film mass transfer resistance.

Hyperuniformity, quasi-long-range correlations, and void-space constraints in maximally random jammed particle packings. II. Anisotropy in particle shape.

Science.gov (United States)

Zachary, Chase E; Jiao, Yang; Torquato, Salvatore

2011-05-01

We extend the results from the first part of this series of two papers by examining hyperuniformity in heterogeneous media composed of impenetrable anisotropic inclusions. Specifically, we consider maximally random jammed (MRJ) packings of hard ellipses and superdisks and show that these systems both possess vanishing infinite-wavelength local-volume-fraction fluctuations and quasi-long-range pair correlations scaling as r(-(d+1)) in d Euclidean dimensions. Our results suggest a strong generalization of a conjecture by Torquato and Stillinger [Phys. Rev. E 68, 041113 (2003)], namely, that all strictly jammed saturated packings of hard particles, including those with size and shape distributions, are hyperuniform with signature quasi-long-range correlations. We show that our arguments concerning the constrained distribution of the void space in MRJ packings directly extend to hard-ellipse and superdisk packings, thereby providing a direct structural explanation for the appearance of hyperuniformity and quasi-long-range correlations in these systems. Additionally, we examine general heterogeneous media with anisotropic inclusions and show unexpectedly that one can decorate a periodic point pattern to obtain a hard-particle system that is not hyperuniform with respect to local-volume-fraction fluctuations. This apparent discrepancy can also be rationalized by appealing to the irregular distribution of the void space arising from the anisotropic shapes of the particles. Our work suggests the intriguing possibility that the MRJ states of hard particles share certain universal features independent of the local properties of the packings, including the packing fraction and average contact number per particle.

Assimilating irregularly spaced sparsely observed turbulent signals with hierarchical Bayesian reduced stochastic filters

International Nuclear Information System (INIS)

Brown, Kristen A.; Harlim, John

2013-01-01

In this paper, we consider a practical filtering approach for assimilating irregularly spaced, sparsely observed turbulent signals through a hierarchical Bayesian reduced stochastic filtering framework. The proposed hierarchical Bayesian approach consists of two steps, blending a data-driven interpolation scheme and the Mean Stochastic Model (MSM) filter. We examine the potential of using the deterministic piecewise linear interpolation scheme and the ordinary kriging scheme in interpolating irregularly spaced raw data to regularly spaced processed data and the importance of dynamical constraint (through MSM) in filtering the processed data on a numerically stiff state estimation problem. In particular, we test this approach on a two-layer quasi-geostrophic model in a two-dimensional domain with a small radius of deformation to mimic ocean turbulence. Our numerical results suggest that the dynamical constraint becomes important when the observation noise variance is large. Second, we find that the filtered estimates with ordinary kriging are superior to those with linear interpolation when observation networks are not too sparse; such robust results are found from numerical simulations with many randomly simulated irregularly spaced observation networks, various observation time intervals, and observation error variances. Third, when the observation network is very sparse, we find that both the kriging and linear interpolations are comparable

Spelling pronunciation and visual preview both facilitate learning to spell irregular word

NARCIS (Netherlands)

Hilte, M.; Reitsma, P.

2006-01-01

Spelling pronunciations are hypothesized to be helpful in building up relatively stable phonologically underpinned orthographic representations, particularly for learning words with irregular phoneme-grapheme correspondences. In a four-week computer-based training, the efficacy of spelling

Pricing and hedging high-dimensional American options : an irregular grid approach

NARCIS (Netherlands)

Berridge, S.; Schumacher, H.

2002-01-01

We propose and test a new method for pricing American options in a high dimensional setting. The method is centred around the approximation of the associated variational inequality on an irregular grid. We approximate the partial differential operator on this grid by appealing to the SDE

Identifying irregularly shaped crime hot-spots using a multiobjective evolutionary algorithm

Science.gov (United States)

Wu, Xiaolan; Grubesic, Tony H.

2010-12-01

Spatial cluster detection techniques are widely used in criminology, geography, epidemiology, and other fields. In particular, spatial scan statistics are popular and efficient techniques for detecting areas of elevated crime or disease events. The majority of spatial scan approaches attempt to delineate geographic zones by evaluating the significance of clusters using likelihood ratio statistics tested with the Poisson distribution. While this can be effective, many scan statistics give preference to circular clusters, diminishing their ability to identify elongated and/or irregular shaped clusters. Although adjusting the shape of the scan window can mitigate some of these problems, both the significance of irregular clusters and their spatial structure must be accounted for in a meaningful way. This paper utilizes a multiobjective evolutionary algorithm to find clusters with maximum significance while quantitatively tracking their geographic structure. Crime data for the city of Cincinnati are utilized to demonstrate the advantages of the new approach and highlight its benefits versus more traditional scan statistics.

Correlation of track irregularities and vehicle responses based on measured data

Science.gov (United States)

Karis, Tomas; Berg, Mats; Stichel, Sebastian; Li, Martin; Thomas, Dirk; Dirks, Babette

2018-06-01

Track geometry quality and dynamic vehicle response are closely related, but do not always correspond with each other in terms of maximum values and standard deviations. This can often be seen to give poor results in analyses with correlation coefficients or regression analysis. Measured data from both the EU project DynoTRAIN and the Swedish Green Train (Gröna Tåget) research programme is used in this paper to evaluate track-vehicle response for three vehicles. A single degree of freedom model is used as an inspiration to divide track-vehicle interaction into three parts, which are analysed in terms of correlation. One part, the vertical axle box acceleration divided by vehicle speed squared (?) and the second spatial derivative of the vertical track irregularities (?), is shown to be the weak link with lower correlation coefficients than the other parts. Future efforts should therefore be directed towards investigating the relation between axle box accelerations and track irregularity second derivatives.

Volume determination of irregularly-shaped quasi-spherical nanoparticles.

Science.gov (United States)

Attota, Ravi Kiran; Liu, Eileen Cherry

2016-11-01

Nanoparticles (NPs) are widely used in diverse application areas, such as medicine, engineering, and cosmetics. The size (or volume) of NPs is one of the most important parameters for their successful application. It is relatively straightforward to determine the volume of regular NPs such as spheres and cubes from a one-dimensional or two-dimensional measurement. However, due to the three-dimensional nature of NPs, it is challenging to determine the proper physical size of many types of regularly and irregularly-shaped quasi-spherical NPs at high-throughput using a single tool. Here, we present a relatively simple method that determines a better volume estimate of NPs by combining measurements from their top-down projection areas and peak heights using two tools. The proposed method is significantly faster and more economical than the electron tomography method. We demonstrate the improved accuracy of the combined method over scanning electron microscopy (SEM) or atomic force microscopy (AFM) alone by using modeling, simulations, and measurements. This study also exposes the existence of inherent measurement biases for both SEM and AFM, which usually produce larger measured diameters with SEM than with AFM. However, in some cases SEM measured diameters appear to have less error compared to AFM measured diameters, especially for widely used IS-NPs such as of gold, and silver. The method provides a much needed, proper high-throughput volumetric measurement method useful for many applications. Graphical Abstract The combined method for volume determination of irregularly-shaped quasi-spherical nanoparticles.

Reproducibility of irregular radiation fields for malignant lymphoma

International Nuclear Information System (INIS)

Mock, U.; Dieckmann, K.; Poetter, R.; Molitor, A.M.; Haverkamp, U.

1998-01-01

Purpose: Radiation treatment for malignant lymphoma requires large field irradiation with irregular blocks according to the individual anatomy and tumor configuration. For determination of safety margins (PTV) we quantitatively analysed the accuracy of field and block placement with regard to different anatomical regions. Patients and Methods: Forty patients with malignant lymphoma were irradiated using the classical supra-/infradiaphragmatic field arrangements. Treatment was performed with 10-MeV photons and irregularly shaped, large opposing fields. We evaluated the accuracy of field and block placements during the treatment courses by comparing the regularly performed verification - with the simulation films. Deviations were determined with respect to the field edges and the central axis, along the x- and z-axis. Results: With regard to the field edges, mean deviations of 2.0 mm and 3.4 mm were found along the x- and z-axis. The corresponding standard deviations were 3.4 mm and 5.5 mm, respectively. With regard to the shielding blocks, mean displacement along the x- and z-axis was 2.2 mm and 3.8 mm. In addition, overall standard deviations of 5.7 mm (x-axis) and 7.1 mm (z-axis) were determined. During the course of time an improved accuracy of block placement was notable. Conclusion: Systematic analysis of port films gives information for a better defining safety margins in external radiotherapy. Evaluation of verification films on a regular basis improves set-up accuracy by reducing displacements. (orig.) [de

The Occurrence of Small-scale Irregularities in the Mid-latitude Ionosphere from SuperDARN HF Radar Observations

Science.gov (United States)

Ruohoniemi, J. M.; Baker, J. B.; Maimaiti, M.; Oksavik, K.; Erickson, P. J.; Scales, W.; Eltrass, A.

2017-12-01

The mid-latitude radars of the SuperDARN network routinely observe backscatter from nighttime decameter-scale F region irregularities at latitudes well equatorward of the auroral boundary. This Sub-Auroral Ionospheric Scatter (SAIS) is strongly distinguished from auroral and SAPS backscatter by low Doppler velocities ( tens m/s) and stable, long-lived ( hours) occurrence in discrete events that are extended in both latitude and longitude. Statistical and event studies of SAIS with the SuperDARN radars indicate that the subauroral F region ionosphere is replete with irregularities during events, at least poleward of the 50° Λ horizon of the North American mid-latitude radars, and that radar observation of SAIS backscatter is then primarily limited by the magnetic aspect condition. Joint experiments with incoherent scatter radar have furnished sets of plasma measurements suitable for testing theories of plasma instability. Modeling work stimulated by the observations has explored the temperature-gradient instability (TGI) and the gradient drift instability (GDI) as possible sources of the irregularities. In this talk we review the findings on the occurrence of the SAIS category of mid-latitude F region irregularities, summarize the results of the modeling work, and discuss future research directions.

Determining the radiative properties of pulverized-coal particles from experiments. Final report

Energy Technology Data Exchange (ETDEWEB)

Menguec, M.P.

1992-02-01

A comprehensive coupled experimental-theoretical study has been performed to determine the effective radiative properties of pulverized-coal/char particles. The results obtained show that the ``effective`` scattering phase function of coal particles are highly forward scattering and show less sensitivity to the size than predicted from the Lorenz-Mie theory. The main reason for this is the presence of smaller size particles associated with each larger particle. Also, the coal/char particle clouds display more side scattering than predicted for the same size range spheres, indicating the irregular shape of the particles and fragmentation. In addition to these, it was observed that in the visible wavelength range the coal absorption is not gray, and slightly vary with the wavelength. These two experimental approaches followed in this study are unique in a sense that the physics of the problem are not approximated. The properties determined include all uncertainties related to the particle shape, size distribution, inhomogeneity and spectral complex index of refraction data. In order to obtain radiative property data over a wider wavelength spectrum, additional ex-situ experiments have been carried out using a Fourier Transform Infrared (FT-IR) Spectrometer. The spectral measurements were performed over the wavelength range of 2 to 22 {mu}m. These results were interpreted to obtain the ``effective`` efficiency factors of coal particles and the corresponding refractive index values. The results clearly show that the coal/char radiative properties display significant wavelength dependency in the infrared spectrum.

Using Little's Irregularity Index in orthodontics: outdated and inaccurate?

LENUS (Irish Health Repository)

Macauley, Donal

2012-12-01

Little\\'s Irregularity Index (LII) was devised to objectively score mandibular incisor alignment for epidemiological studies but has been extended to assess the relative performance of orthodontic brackets, retainer or treatment modalities. Our aim was to examine the repeatability and precision of LII measurements of four independent examiners on the maxillary arch of orthodontic patients. The hypothesis was that the reproducibility of individual contact point displacement measurements, used to calculate the LII score, are inappropriate.

Snow particles extracted from X-ray computed microtomography imagery and their single-scattering properties

Science.gov (United States)

Ishimoto, Hiroshi; Adachi, Satoru; Yamaguchi, Satoru; Tanikawa, Tomonori; Aoki, Teruo; Masuda, Kazuhiko

2018-04-01

Sizes and shapes of snow particles were determined from X-ray computed microtomography (micro-CT) images, and their single-scattering properties were calculated at visible and near-infrared wavelengths using a Geometrical Optics Method (GOM). We analyzed seven snow samples including fresh and aged artificial snow and natural snow obtained from field samples. Individual snow particles were numerically extracted, and the shape of each snow particle was defined by applying a rendering method. The size distribution and specific surface area distribution were estimated from the geometrical properties of the snow particles, and an effective particle radius was derived for each snow sample. The GOM calculations at wavelengths of 0.532 and 1.242 μm revealed that the realistic snow particles had similar scattering phase functions as those of previously modeled irregular shaped particles. Furthermore, distinct dendritic particles had a characteristic scattering phase function and asymmetry factor. The single-scattering properties of particles of effective radius reff were compared with the size-averaged single-scattering properties. We found that the particles of reff could be used as representative particles for calculating the average single-scattering properties of the snow. Furthermore, the single-scattering properties of the micro-CT particles were compared to those of particle shape models using our current snow retrieval algorithm. For the single-scattering phase function, the results of the micro-CT particles were consistent with those of a conceptual two-shape model. However, the particle size dependence differed for the single-scattering albedo and asymmetry factor.

A Novel Energy Yields Calculation Method for Irregular Wind Farm Layout

DEFF Research Database (Denmark)

Hou, Peng; Hu, Weihao; Soltani, Mohsen

2015-01-01

Due to the increasing size of offshore wind farm, the impact of the wake effect on energy yields become more and more evident. The Seafloor topography would limit the layout of the wind farm so that irregular layout is usually adopted inlarge scale offshore wind farm. However, the calculation...

Electrostatic lower hybrid waves excited by electromagnetic whistler mode waves scattering from planar magnetic-field-aligned plasma density irregularities

International Nuclear Information System (INIS)

Bell, T.F.; Ngo, H.D.

1990-01-01

Recent satellite observations demonstrate that high amplitude, short wavelength (5 m ≤ λ ≤ 100 m) electrostatic waves are commonly excited by electromagnetic whistler mode waves propagating in regions of the magnetosphere and topside ionosphere where small-scale magnetic-field-aligned plasma density irregularities are thought to exist. A new theoretical model of this phenomenon is presented, based upon passive linear scattering in a cold magnetoplasma. In this model the electrostatic waves are excited by linear mode coupling as the incident electromagnetic whistler mode waves scatter from the magnetic-field-aligned plasma density irregularities. The excited short wavelength waves are quasi-electrostatic whistler mode waves, a type of lower hybrid wave, whose wave normal lies near the whistler mode resonance cone where the wave refractive index becomes very large. The amplitude of the excited electrostatic lower hybrid waves is calculated for a wide range of values of input electromagnetic wave frequency, wave normal direction, electron plasma frequency, gyrofrequency, ion composition, and irregularity scale and density enhancement. Results indicate that high amplitude lower hybrid waves can be excited over a wide range of parameters for irregularity density enhancements as low as 5% whenever the scale of the irregularity is of the same order as the lower hybrid wavelength

Drift motions of small-scale irregularities in the high-latitude F region: An experimental comparison with plasma drift motions

International Nuclear Information System (INIS)

Ruohoniemi, J.M.; Greenwald, R.A.; Baker, K.B.; Villain, J.P.; McCready, M.A.

1987-01-01

On the evening of January 6, 1986, coordinated observations were carried out with the Johns Hopkins University Applied Physics Laboratory HF coherent scatter radar at Goose Bay, Labrador, and the SRI International incoherent scatter radar at Sondre Stromfjord, Greenland. The common field of view comprised a section of high-latitude F region ionosphere centered on the great circle plane between the radar sites. Over a 40-min period, the HF radar observed strong backscatter from small-scale (13.9 m) field-aligned irregularities. The bulk line-of-sight drift velocity of the irregularities is deduced from the backscatter data. The returns collected simultaneously with the incoherent scatter radar are processed for estimates of the mean line-of-sight ion velocity. Approximately 100 distinct comparisons are possible between the two sets of velocity estimates. Reversals exceeding 1,000 m/s are present in both. In this paper, the authors demonstrate a correspondence between the measured irregularity and ion drifts that is consistent with the supposition that the motion of the irregularities is dominated by convective drift of the ambient plasma. This indicates that the small-scale irregularities detected by HF radars in the high-latitude F region can serve as tracers of ionospheric convective drift

Exploring Individual Differences in Irregular Word Recognition among Children with Early-Emerging and Late-Emerging Word Reading Difficulty

Science.gov (United States)

Steacy, Laura M.; Kearns, Devin M.; Gilbert, Jennifer K.; Compton, Donald L.; Cho, Eunsoo; Lindstrom, Esther R.; Collins, Alyson A.

2017-01-01

Models of irregular word reading that take into account both child- and word-level predictors have not been evaluated in typically developing children and children with reading difficulty (RD). The purpose of the present study was to model individual differences in irregular word reading ability among 5th grade children (N = 170), oversampled for…

An experimental study of irregular wave forces on multiple quasi-ellipse caissons

Science.gov (United States)

Ren, Xiaozhong; Zhang, Peng; Ma, Yuxiang; Meng, Yufan

2014-09-01

An experimental investigation of irregular wave forces on quasi-ellipse caisson structures is presented. Irregular waves were generated based on the Jonswap spectrum with two significant wave heights, and the spectrum peak periods range from 1.19 s to 1.81 s. Incident wave directions relative to the centre line of the multiple caissons are from 0° to 22.5°. The spacing between caissons ranges from 2 to 3 times that of the width of the caisson. The effects of these parameters on the wave forces of both the perforated and non-perforated caissons were compared and analyzed. It was found that the perforated caisson can reduce wave forces, especially in the transverse direction. Furthermore, the relative interval and incident wave direction have significant effects on the wave forces in the case of multiple caissons.

Irregular Firing and High-Conductance States in Spinal Motoneurons during Scratching and Swimming

DEFF Research Database (Denmark)

Guzulaitis, Robertas; Hounsgaard, Jorn; Alaburda, Aidas

2016-01-01

UNLABELLED: Intense synaptic transmission during scratch network activity increases conductance and induces irregular firing in spinal motoneurons. It is not known whether this high-conductance state is a select feature for scratching or a property that goes with spinal motor network activity...... in general. Here we compare conductance and firing patterns in spinal motoneurons during network activity for scratching and swimming in an ex vivo carapace-spinal cord preparation from adult turtles (Trachemys scripta elegans). The pattern and relative engagement of motoneurons are distinctly different...... in scratching and swimming. Nevertheless, we found increased synaptic fluctuations in membrane potential, irregular firing, and increased conductance in spinal motoneurons during scratch and swim network activity. Our finding indicates that intense synaptic activation of motoneurons is a general feature...

Compensation for unfavorable characteristics of irregular individual shift rotas.

Science.gov (United States)

Knauth, Peter; Jung, Detlev; Bopp, Winfried; Gauderer, Patric C; Gissel, Andreas

2006-01-01

Some employees of TV companies, such as those who produce remote TV programs, have to cope with very irregular rotas and many short-term schedule deviations. Many of these employees complain about the negative effects of such on their wellbeing and private life. Therefore, a working group of employers, council representatives, and researchers developed a so-called bonus system. Based on the criteria of the BESIAK system, the following list of criteria for the ergonomic assessment of irregular shift systems was developed: proportion of night hours worked between 22 : 00 and 01 : 00 h and between 06 : 00 and 07 : 00 h, proportion of night hours worked between 01 : 00 and 06 : 00 h, number of successive night shifts, number of successive working days, number of shifts longer than 9 h, proportion of phase advances, off hours on weekends, work hours between 17 : 00 and 23 : 00 h from Monday to Friday, number of working days with leisure time at remote places, and sudden deviations from the planned shift rota. Each individual rota was evaluated in retrospect. If pre-defined thresholds of criteria were surpassed, bonus points were added to the worker's account. In general, more bonus points add up to more free time. Only in particular cases was monetary compensation possible for some criteria. The bonus point system, which was implemented in the year 2002 for about 850 employees of the TV company, has the advantages of more transparency concerning the unfavorable characteristics of working-time arrangements, incentive for superiors to design "good" rosters that avoid the bonus point thresholds (to reduce costs), positive short-term effects on the employee social life, and expected positive long-term effects on the employee health. In general, the most promising approach to cope with the problems of shift workers in irregular and flexible shift systems seems to be to increase their influence on the arrangement of working times. If this is not possible, bonus point systems

Comparison of ice particle morphology crushed from ice chunk and directly solidified from droplet

Energy Technology Data Exchange (ETDEWEB)

Yang, J.H.; Yoon, Y.S.; Bang, S.Y. [Dongguk Univ., Pil-dong, Chung-gu, Seoul (Korea, Republic of). Dept. of Mechanical Engineering

2008-07-01

In order to investigate the transition kinetics of ice to hydrate and to produce standard specimens of hydrate pellet from prepared hydrate powders, fine ice beads with uniform diameters must be fabricated. This paper discussed the construction of several experimental setups for the fabrication of fine ice particle generation. The ultrasonic nozzle was used to produce fine mist which solidified near the free surface of liquid nitrogen bath. The shape and population distribution of ice bead diameters was analyzed. The study also compared ice particles produced by crushing. The surface morphology of ice particles produced with a ball mill was also examined. Experimental results were obtained for an ice shaver, ball mill, bowl for grinding medicine, and ultrasonic nozzle. It was concluded that the information generated from the study was useful in estimating the macroscopic flow characteristics such as permeability of bulk powder and in determining mean effective diameter of irregular shaped particles. Future work was also noted as being underway with different experiments for other cases with different operating conditions. 5 refs., 5 figs.

UTILITARIAN OPACITY MODEL FOR AGGREGATE PARTICLES IN PROTOPLANETARY NEBULAE AND EXOPLANET ATMOSPHERES

International Nuclear Information System (INIS)

Cuzzi, Jeffrey N.; Davis, Sanford S.; Estrada, Paul R.

2014-01-01

As small solid grains grow into larger ones in protoplanetary nebulae, or in the cloudy atmospheres of exoplanets, they generally form porous aggregates rather than solid spheres. A number of previous studies have used highly sophisticated schemes to calculate opacity models for irregular, porous particles with sizes much smaller than a wavelength. However, mere growth itself can affect the opacity of the medium in far more significant ways than the detailed compositional and/or structural differences between grain constituents once aggregate particle sizes exceed the relevant wavelengths. This physics is not new; our goal here is to provide a model that provides physical insight and is simple to use in the increasing number of protoplanetary nebula evolution and exoplanet atmosphere models appearing in recent years, yet quantitatively captures the main radiative properties of mixtures of particles of arbitrary size, porosity, and composition. The model is a simple combination of effective medium theory with small-particle closed-form expressions, combined with suitably chosen transitions to geometric optics behavior. Calculations of wavelength-dependent emission and Rosseland mean opacity are shown and compared with Mie theory. The model's fidelity is very good in all comparisons we have made except in cases involving pure metal particles or monochromatic opacities for solid particles with sizes comparable to the wavelength

Pleural irregularities and mediastinal pleural involvement in early stages of malignant pleural mesothelioma and benign asbestos pleural effusion.

Science.gov (United States)

Kato, Katsuya; Gemba, Kenichi; Fujimoto, Nobukazu; Aoe, Keisuke; Takeshima, Yukio; Inai, Kouki; Kishimoto, Takumi

2016-09-01

To elucidate differences in the level and localization of pleural irregularities in early malignant pleural mesothelioma (eMPM) and benign asbestos pleural effusion (BAPE) using CT. Retrospective assessment of CT findings of consecutive patients with BAPE at a single centre and patients with eMPM reported in Japanese vital statistics. Thirty-six patients with confirmed diagnoses of BAPE and sixty-six patients with confirmed diagnoses of eMPM (mesothelioma stages T1 or T2) were included. Informed consent, CT scans, and clinical and pathologic details were obtained for all patients and were reviewed by one radiologist, two pathologists, and two pulmonologists. Asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening were assessed in all patients. Prevalence of asbestosis, pleural plaque, rounded atelectasis, and diffuse pleural thickening was significantly higher in the BAPE group. Low-level irregularity was more common in the BAPE group (ppleural irregularity was not observed in any patients in the BAPE group, although 55% of patients in the eMPM group showed interlobar pleural irregularity. Mediastinal pleural involvement was observed in 74% of patients in the eMPM group and had a positive predictive value of 89%. This study demonstrates that the level and localization of plural irregularities significantly differed between patients with BAPE and eMPM. Large-scale prospective studies are needed to fully establish the diagnostic utility of such differences. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Efficient irregular wavefront propagation algorithms on Intel® Xeon Phi™

Science.gov (United States)

Gomes, Jeremias M.; Teodoro, George; de Melo, Alba; Kong, Jun; Kurc, Tahsin; Saltz, Joel H.

2016-01-01

We investigate the execution of the Irregular Wavefront Propagation Pattern (IWPP), a fundamental computing structure used in several image analysis operations, on the Intel® Xeon Phi™ co-processor. An efficient implementation of IWPP on the Xeon Phi is a challenging problem because of IWPP’s irregularity and the use of atomic instructions in the original IWPP algorithm to resolve race conditions. On the Xeon Phi, the use of SIMD and vectorization instructions is critical to attain high performance. However, SIMD atomic instructions are not supported. Therefore, we propose a new IWPP algorithm that can take advantage of the supported SIMD instruction set. We also evaluate an alternate storage container (priority queue) to track active elements in the wavefront in an effort to improve the parallel algorithm efficiency. The new IWPP algorithm is evaluated with Morphological Reconstruction and Imfill operations as use cases. Our results show performance improvements of up to 5.63× on top of the original IWPP due to vectorization. Moreover, the new IWPP achieves speedups of 45.7× and 1.62×, respectively, as compared to efficient CPU and GPU implementations. PMID:27298591

Efficient irregular wavefront propagation algorithms on Intel® Xeon Phi™.

Science.gov (United States)

Gomes, Jeremias M; Teodoro, George; de Melo, Alba; Kong, Jun; Kurc, Tahsin; Saltz, Joel H

2015-10-01

We investigate the execution of the Irregular Wavefront Propagation Pattern (IWPP), a fundamental computing structure used in several image analysis operations, on the Intel ® Xeon Phi ™ co-processor. An efficient implementation of IWPP on the Xeon Phi is a challenging problem because of IWPP's irregularity and the use of atomic instructions in the original IWPP algorithm to resolve race conditions. On the Xeon Phi, the use of SIMD and vectorization instructions is critical to attain high performance. However, SIMD atomic instructions are not supported. Therefore, we propose a new IWPP algorithm that can take advantage of the supported SIMD instruction set. We also evaluate an alternate storage container (priority queue) to track active elements in the wavefront in an effort to improve the parallel algorithm efficiency. The new IWPP algorithm is evaluated with Morphological Reconstruction and Imfill operations as use cases. Our results show performance improvements of up to 5.63 × on top of the original IWPP due to vectorization. Moreover, the new IWPP achieves speedups of 45.7 × and 1.62 × , respectively, as compared to efficient CPU and GPU implementations.

Analysis of irregular opacities of silicosis using computed tomography

International Nuclear Information System (INIS)

Maeda, Atsushi; Shida, Hisao; Chiyotani, Keizo; Saito, Kenichi; Mishina, Michihito

1983-01-01

Classification in used to codify Chest CT images of abnormalities of the lung in a simple reproducible manner. Simbols to record CT features of importance are listed. We applied CT to 92 cases of silicosis and roentgenological analysis was performed. Bullae, honeycombing, cavity, emphysema, pleural thickning and calcification were more clearly demonstrated in CT images than routine chest roentgenograms. Irregular opacities were considered to be a combined profusion of small round and streak or strand. (author)

On H-irregularity strengths of G-amalgamation of graphs

Directory of Open Access Journals (Sweden)

Faraha Ashraf

2017-10-01

Full Text Available A simple graph G=(V(G,E(G admits an H-covering if every edge in E(G belongs at least to one subgraph of G isomorphic to a given graph H. Then the graph G admitting H-covering admits an H-irregular total k-labeling f: V(G U E(G \\to {1, 2, ..., k} if for every two different subgraphs H' and H'' isomorphic to H there is $wt_{f}(H' \

Formation of dwarf ellipticals and dwarf irregular galaxies by interaction of giant galaxies under environmental influence

OpenAIRE

Chattopadhyay, Tanuka; Debsarma, Suma; Karmakar, Pradip; Davoust, Emmanuel

2014-01-01

A model is proposed for the formation of gas-rich dwarf irregular galaxies and gas-poor, rotating dwarf elliptical galaxies following the interaction between two giant galaxies as a function of space density. The formation of dwarf galaxies is considered to depend on a random variable, the tidal index theta, an environmental parameter defined by Karachentsev et al. (2004), such that for theta less than zero, the formation of dwarf irregular galaxy is assured whereas for theta greater than zer...

Long wavelength irregularities in the equatorial electrojet

International Nuclear Information System (INIS)

Kudeki, E.; Farley, D.T.; Fejer, B.G.

1982-01-01

We have used the radar interferometer technique at Jicamarca to study in detail irregularities with wavelengths of a few kilometers generated in the unstable equatorial electrojet plasma during strong type 1 conditions. In-situ rocket observations of the same instability process are discussed in a companion paper. These large scale primary waves travel essentially horizontally and have large amplitudes. The vertical electron drift velocities driven by the horizontal wave electric fields reach or exceed the ion-acoustic velocity even though the horizontal phase velocity of the wave is considerably smaller. A straightforward extension to the long wavelength regime of the usual linear theory of the electrojet instability explains this and several other observed features of these dominant primary waves

Irregular employment amongst migrants in Spanish cities.

Science.gov (United States)

Sole, C; Ribas, N; Bergalli, V; Parella, S

1998-04-01

This article presents the irregular employment situation of non-European union immigrants in Spanish cities. Foreign labor is remarkable for its heterogeneity in terms of country of origin, demographic characteristics, and the different ways in which immigrants have entered the job market. Legal immigrants tend to concentrate in five different branches of activity, such as domestic service (mostly women), hotel and restaurant industry, agriculture, building and retail trade. Migrants who work in agriculture suffer the worst labor conditions than all other migrants. However, all migrants experience difficulty in obtaining residency and labor permits. Four integration strategies among Moroccan immigrants in Catalonia are discussed and can be viewed as support networks of the immigrants.

Why type 2 supernovae do not explode in irregular galaxies

International Nuclear Information System (INIS)

Shklovskij, I.S.

1984-01-01

The conclusion is drawn that reason for an absence of type 2 supernovae explosions in irregular galaxies is their peculiar chemical composition. The observed lack of stellar wind from massive hot giants is due to relatively low heavy element abundance. For this reason evolving massive stars do not form an extended dense envelopes that is a necessary condition for the type 2 supernova phenomenon

Experimental light scattering by small particles in Amsterdam and Granada

Directory of Open Access Journals (Sweden)

Volten H.

2010-06-01

Full Text Available We report on two light scattering instruments located in Amsterdam and Granada, respectively. These instruments enable measuring scattering matrices as functions of the scattering angle of collections of randomly orieneted irregular particles. In the past decades, the experimental setup located in Amsterdam, The Netherlands, has produced a significant amount of experimental data. Unfortunately, this setup was officially closed a couple of years ago. We also present a modernized descendant of the Dutch experimental setup recently constructed at the Instituto de Astrofísica de Andalucía (IAA in Granada, Spain. We give a brief description of the instruments, and present some representative results.

Numerical Investigation of the Influence of the Input Air Irregularity on the Performance of Turbofan Jet Engine

Science.gov (United States)

Novikova, Y.; Zubanov, V.

2018-01-01

The article describes the numerical investigation of the input air irregularity influence of turbofan engine on its characteristics. The investigated fan has a wide-blade, an inlet diameter about 2 meters, a pressure ratio about 1.6 and the bypass ratio about 4.8. The flow irregularity was simulated by the flap input in the fan inlet channel. Input of flap was carried out by an amount of 10 to 22,5% of the input channel diameter with increments of 2,5%. A nonlinear harmonic analysis (NLH-analysis) of NUMECA Fine/Turbo software was used to study the flow irregularity. The behavior of the calculated LPC characteristics repeats the experiment behavior, but there is a quantitative difference: the calculated efficiency and pressure ratio of booster consistent with the experimental data within 3% and 2% respectively, the calculated efficiency and pressure ratio of fan duct - within 4% and 2.5% respectively. An increasing the level of air irregularity in the input stage of the fan reduces the calculated mass flow, maximum pressure ratio and efficiency. With the value of flap input 12.5%, reducing the maximum air flow is 1.44%, lowering the maximum pressure ratio is 2.6%, efficiency decreasing is 3.1%.

Time-Scale and Time-Frequency Analyses of Irregularly Sampled Astronomical Time Series

Directory of Open Access Journals (Sweden)

S. Roques

2005-09-01

Full Text Available We evaluate the quality of spectral restoration in the case of irregular sampled signals in astronomy. We study in details a time-scale method leading to a global wavelet spectrum comparable to the Fourier period, and a time-frequency matching pursuit allowing us to identify the frequencies and to control the error propagation. In both cases, the signals are first resampled with a linear interpolation. Both results are compared with those obtained using Lomb's periodogram and using the weighted waveletZ-transform developed in astronomy for unevenly sampled variable stars observations. These approaches are applied to simulations and to light variations of four variable stars. This leads to the conclusion that the matching pursuit is more efficient for recovering the spectral contents of a pulsating star, even with a preliminary resampling. In particular, the results are almost independent of the quality of the initial irregular sampling.

Spatial relationship of 1-meter equatorial spread-F irregularities and depletions in total electron content

International Nuclear Information System (INIS)

Tsunoda, R.T.; Towle, D.M.

1979-01-01

An experiment was conducted at Kwajalein Atoll, Marshall Islands to investigate the spatial relationship of 1-m equatorial spread-F irregularities to total electron content (TEC) depletions. A high-power radar was operated (1) in a backscatter scan mode to spatially map the distribution of 1-m irregularities, and (2) in a dual-frequency, satellite-track mode to obtain the longitudinal TEC variations. We show that radar backscatter ''plumes'' found in the disturbed, nighttime equatorial ionosphere are longitudinally coincident with TEC depletions. We suggest that the TEC depletions are probably due to the presence of plasma ''bubbles'' in the equatorial F layer

An Efficient Heuristic Approach for Irregular Cutting Stock Problem in Ship Building Industry

Directory of Open Access Journals (Sweden)

Yan-xin Xu

2016-01-01

Full Text Available This paper presents an efficient approach for solving a real two-dimensional irregular cutting stock problem in ship building industry. Cutting stock problem is a common cutting and packing problem that arises in a variety of industrial applications. A modification of selection heuristic Exact Fit is applied in our research. In the case referring to irregular shapes, a placement heuristics is more important to construct a complete solution. A placement heuristic relating to bottom-left-fill is presented. We evaluate the proposed approach using generated instance only with convex shapes in literatures and some instances with nonconvex shapes based on real problem from ship building industry. The results demonstrate that the effectiveness and efficiency of the proposed approach are significantly better than some conventional heuristics.

Nonlinear radiated MHD flow of nanoliquids due to a rotating disk with irregular heat source and heat flux condition

Science.gov (United States)

Mahanthesh, B.; Gireesha, B. J.; Shehzad, S. A.; Rauf, A.; Kumar, P. B. Sampath

2018-05-01

This research is made to visualize the nonlinear radiated flow of hydromagnetic nano-fluid induced due to rotation of the disk. The considered nano-fluid is a mixture of water and Ti6Al4V or AA7072 nano-particles. The various shapes of nanoparticles like lamina, column, sphere, tetrahedron and hexahedron are chosen in the analysis. The irregular heat source and nonlinear radiative terms are accounted in the law of energy. We used the heat flux condition instead of constant surface temperature condition. Heat flux condition is more relativistic and according to physical nature of the problem. The problem is made dimensionless with the help of suitable similarity constraints. The Runge-Kutta-Fehlberg scheme is adopted to find the numerical solutions of governing nonlinear ordinary differential systems. The solutions are plotted by considering the various values of emerging physical constraints. The effects of various shapes of nanoparticles are drawn and discussed.

The effect of calcium on the composition and physical properties of whey protein particles prepared using emulsification.

Science.gov (United States)

Westerik, Nieke; Scholten, Elke; Corredig, Milena

2015-06-15

Protein microparticles were formed through emulsification of 25% (w/w) whey protein isolate (WPI) solutions containing various concentrations of calcium (0.0-400.0mM) in an oil phase stabilized by polyglycerol polyricinoleate (PGPR). The emulsions were heated (at 80°C) and the microparticles subsequently re-dispersed in an aqueous phase. Light microscopy and scanning electron microscopy (SEM) images revealed that control particles and those prepared with 7.4mM calcium were spherical and smooth. Particles prepared with 15.0mM calcium gained an irregular, cauliflower-like structure, and at concentrations larger than 30.0mM, shells formed and the particles were no longer spherical. These results describe, for the first time, the potential of modulating the properties of dense whey protein particles by using calcium, and may be used as structuring agents for the design of functional food matrices with increased protein and calcium content. Copyright © 2015. Published by Elsevier Ltd.

Active Absorption of Irregular Gravity Waves in BEM-Models

DEFF Research Database (Denmark)

Brorsen, Michael; Frigaard, Peter

1992-01-01

The boundary element method is applied to the computation of irregular gravity waves. The boundary conditions at the open boundaries are obtained by a digital filtering technique, where the surface elevations in front of the open boundary are filtered numerically yielding the velocity to be presc...... to be prescribed at the boundary. By numerical examples it is shown that well designed filters can reduce the wave reflection to a few per cent over a frequency range corresponding to a Jonswap spectrum....

Imaging irregular magma reservoirs with InSAR and GPS observations: Application to Kilauea and Copahue volcanoes

Science.gov (United States)

Lundgren, P.; Camacho, A.; Poland, M. P.; Miklius, A.; Samsonov, S. V.; Milillo, P.

2013-12-01

The availability of synthetic aperture radar (SAR) interferometry (InSAR) data has increased our awareness of the complexity of volcano deformation sources. InSAR's spatial completeness helps identify or clarify source process mechanisms at volcanoes (i.e. Mt. Etna east flank motion; Lazufre crustal magma body; Kilauea dike complexity) and also improves potential model realism. In recent years, Bayesian inference methods have gained widespread use because of their ability to constrain not only source model parameters, but also their uncertainties. They are computationally intensive, however, which tends to limit them to a few geometrically rather simple source representations (for example, spheres). An alternative approach involves solving for irregular pressure and/or density sources from a three-dimensional (3-D) grid of source/density cells. This method has the ability to solve for arbitrarily shaped bodies of constant absolute pressure/density difference. We compare results for both Bayesian (a Markov chain Monte Carlo algorithm) and the irregular source methods for two volcanoes: Kilauea, Hawaii, and Copahue, Argentina-Chile border. Kilauea has extensive InSAR and GPS databases from which to explore the results for the irregular method with respect to the Bayesian approach, prior models, and an extensive set of ancillary data. One caveat, however, is the current restriction in the irregular model inversion to volume-pressure sources (and at a single excess pressure change), which limits its application in cases where sources such as faults or dikes are present. Preliminary results for Kilauea summit deflation during the March 2011 Kamoamoa eruption suggests a northeast-elongated magma body lying roughly 1-1.5 km below the surface. Copahue is a southern Andes volcano that has been inflating since early 2012, with intermittent summit eruptive activity since late 2012. We have an extensive InSAR time series from RADARSAT-2 and COSMO-SkyMed data, although both are

Wireless sensing without sensors—an experimental study of motion/intrusion detection using RF irregularity

International Nuclear Information System (INIS)

Lee, Pius W Q; Tan, Hwee-Pink; Seah, Winston K G; Yao, Zexi

2010-01-01

Motion and intrusion detection are often cited as wireless sensor network (WSN) applications with typical configurations comprising clusters of wireless nodes equipped with motion sensors to detect human motion. Currently, WSN performance is subjected to several constraints, namely radio irregularity and finite on-board computation/energy resources. Radio irregularity in radio frequency (RF) propagation rises to a higher level in the presence of human activity due to the absorption effect of the human body. In this paper, we investigate the feasibility of monitoring RF transmission for the purpose of intrusion detection through experimentation. With empirical data obtained from the Crossbow TelosB platform in several different environments, the impact of human activity on the signal strength of RF signals in a WSN is evaluated. We then propose a novel approach to intrusion detection by turning a constraint in WSN, namely radio irregularity, into an advantage for the purpose of intrusion detection, using signal fluctuations to detect the presence of human activity within the WSN. Unlike RF fingerprinting, the 'intruders' here neither transmit nor receive any RF signals. By enabling existing wireless infrastructures to serve as intrusion detectors instead of deploying numerous costly sensors, this approach shows great promise for providing novel solutions

A study of the H I and optical properties of Low Surface Brightness galaxies: spirals, dwarfs, and irregulars

Science.gov (United States)

Honey, M.; van Driel, W.; Das, M.; Martin, J.-M.

2018-06-01

We present a study of the H I and optical properties of nearby (z ≤ 0.1) Low Surface Brightness galaxies (LSBGs). We started with a literature sample of ˜900 LSBGs and divided them into three morphological classes: spirals, irregulars, and dwarfs. Of these, we could use ˜490 LSBGs to study their H I and stellar masses, colours, and colour-magnitude diagrams, and local environment, compare them with normal, High Surface Brightness (HSB) galaxies and determine the differences between the three morphological classes. We found that LSB and HSB galaxies span a similar range in H I and stellar masses, and have a similar M_{H I}/M⋆-M⋆ relationship. Among the LSBGs, as expected, the spirals have the highest average H I and stellar masses, both of about 109.8 M⊙. The LSGBs' (g - r) integrated colour is nearly constant as function of H I mass for all classes. In the colour-magnitude diagram, the spirals are spread over the red and blue regions whereas the irregulars and dwarfs are confined to the blue region. The spirals also exhibit a steeper slope in the M_{H I}/M⋆-M⋆ plane. Within their local environment, we confirmed that LSBGs are more isolated than HSB galaxies, and LSB spirals more isolated than irregulars and dwarfs. Kolmogorov-Smirnov statistical tests on the H I mass, stellar mass, and number of neighbours indicate that the spirals are a statistically different population from the dwarfs and irregulars. This suggests that the spirals may have different formation and H I evolution than the dwarfs and irregulars.

Association between Body Weight Changes and Menstrual Irregularity: The Korea National Health and Nutrition Examination Survey 2010 to 2012

Directory of Open Access Journals (Sweden)

Kyung Min Ko

2017-06-01

Full Text Available BackgroundMenstrual irregularity is an indicator of endocrine disorders and reproductive health status. It is associated with various diseases and medical conditions, including obesity and underweight. We aimed to assess the association between body weight changes and menstrual irregularity in Korean women.MethodsA total of 4,621 women 19 to 54 years of age who participated in the 2010 to 2012 Korea National Health and Nutrition Examination Survey were included in this study. Self-reported questionnaires were used to collect medical information assessing menstrual health status and body weight changes. Odds ratios (ORs and 95% confidence interval (CI were calculated to evaluate the association between body weight changes and menstrual irregularity.ResultsSignificantly higher ORs (95% CI were observed in the association between menstrual irregularity and both weight loss (OR, 1.74; 95% CI, 1.22 to 2.48 and weight gain (OR, 1.45; 95% CI, 1.13 to 1.86 after adjusting for age, body mass index, current smoking, heavy alcohol drinking, regular exercise, calorie intake, education, income, metabolic syndrome, age of menarche, parity, and stress perception. Of note, significant associations were only observed in subjects with obesity and abdominal obesity, but not in non-obese or non-abdominally obese subjects. U-shaped patterns were demonstrated in both obese and abdominally obese subjects, indicating that greater changes in body weight are associated with higher odds of menstrual irregularity.ConclusionWe found a U-shaped pattern of association between body weight changes and menstrual irregularity among obese women in the general Korean population. This result indicates that not only proper weight management but also changes in body weight may influence the regulation of the menstrual cycle.

Association between Body Weight Changes and Menstrual Irregularity: The Korea National Health and Nutrition Examination Survey 2010 to 2012.

Science.gov (United States)

Ko, Kyung Min; Han, Kyungdo; Chung, Youn Jee; Yoon, Kun Ho; Park, Yong Gyu; Lee, Seung Hwan

2017-06-01

Menstrual irregularity is an indicator of endocrine disorders and reproductive health status. It is associated with various diseases and medical conditions, including obesity and underweight. We aimed to assess the association between body weight changes and menstrual irregularity in Korean women. A total of 4,621 women 19 to 54 years of age who participated in the 2010 to 2012 Korea National Health and Nutrition Examination Survey were included in this study. Self-reported questionnaires were used to collect medical information assessing menstrual health status and body weight changes. Odds ratios (ORs) and 95% confidence interval (CI) were calculated to evaluate the association between body weight changes and menstrual irregularity. Significantly higher ORs (95% CI) were observed in the association between menstrual irregularity and both weight loss (OR, 1.74; 95% CI, 1.22 to 2.48) and weight gain (OR, 1.45; 95% CI, 1.13 to 1.86) after adjusting for age, body mass index, current smoking, heavy alcohol drinking, regular exercise, calorie intake, education, income, metabolic syndrome, age of menarche, parity, and stress perception. Of note, significant associations were only observed in subjects with obesity and abdominal obesity, but not in non-obese or non-abdominally obese subjects. U-shaped patterns were demonstrated in both obese and abdominally obese subjects, indicating that greater changes in body weight are associated with higher odds of menstrual irregularity. We found a U-shaped pattern of association between body weight changes and menstrual irregularity among obese women in the general Korean population. This result indicates that not only proper weight management but also changes in body weight may influence the regulation of the menstrual cycle. Copyright © 2017 Korean Endocrine Society

Dryout heat flux experiments with deep heterogeneous particle bed

International Nuclear Information System (INIS)

Lindholm, I.; Holmstroem, S.; Miettinen, J.; Lestinen, V.; Hyvaerinen, J.; Pankakoski, P.; Sjoevall, H.

2006-01-01

A test facility has been constructed at Technical Research Centre of Finland (VTT) to simulate as accurately as possible the ex-vessel core particle bed in the conditions of Olkiluoto nuclear power plant. The STYX particle bed reproduces the anticipated depth of the bed and the size range of particles having irregular shape. The bed is immersed in water, creating top flooding conditions, and internally heated by an array of electrical resistance heating elements. Dryout tests have been successfully conducted at 0.1-0.7 MPa pressure for both uniformly mixed and stratified bed geometries. In all tests, including the stratified ones, the dry zone first formed near the bottom of the bed. The measured dryout heat fluxes increased with increasing pressure, from 232 kW/m 2 at near atmospheric pressure to 451 kW/m 2 at 0.7 MPa pressure. The data show some scatter even for the uniform bed. The tests with the stratified bed indicate a clear reduction of critical power due to the presence of a layer of small particles on top of the uniform bed. Comparison of data with various critical power (dryout heat flux) correlations for porous media shows that the most important parameter in the models is the effective particle diameter. Adiabatic debris bed flow resistance measurements were conducted to determine the most representative particle diameter. This diameter is close, but not equal, to the particle number-weighted average diameter of the bed material. With it, uniform bed data can be calculated to within an accuracy of 3-28% using Lipinski's 0-D model. In the stratified bed experiments, it appears that the top layer was partially fluidized, hence the measured critical power was significantly higher than calculated. Future experiments are being planned with denser top layer material to eliminate non-prototypic fluidization

Details of regional particle deposition and airflow structures in a realistic model of human tracheobronchial airways: two-phase flow simulation.

Science.gov (United States)

Rahimi-Gorji, Mohammad; Gorji, Tahereh B; Gorji-Bandpy, Mofid

2016-07-01

In the present investigation, detailed two-phase flow modeling of airflow, transport and deposition of micro-particles (1-10µm) in a realistic tracheobronchial airway geometry based on CT scan images under various breathing conditions (i.e. 10-60l/min) was considered. Lagrangian particle tracking has been used to investigate the particle deposition patterns in a model comprising mouth up to generation G6 of tracheobronchial airways. The results demonstrated that during all breathing patterns, the maximum velocity change occurred in the narrow throat region (Larynx). Due to implementing a realistic geometry for simulations, many irregularities and bending deflections exist in the airways model. Thereby, at higher inhalation rates, these areas are prone to vortical effects which tend to entrap the inhaled particles. According to the results, deposition fraction has a direct relationship with particle aerodynamic diameter (for dp=1-10µm). Enhancing inhalation flow rate and particle size will largely increase the inertial force and consequently, more particle deposition is evident suggesting that inertial impaction is the dominant deposition mechanism in tracheobronchial airways. Copyright © 2016 Elsevier Ltd. All rights reserved.

Entity’s Irregular Demand Scheduling of the Wholesale Electricity Market based on the Forecast of Hourly Price Ratios

Directory of Open Access Journals (Sweden)

O. V. Russkov

2015-01-01

Full Text Available The article considers a hot issue to forecast electric power demand amounts and prices for the entities of wholesale electricity market (WEM, which are in capacity of a large user with production technology requirements prevailing over hourly energy planning ones. An electric power demand of such entities is on irregular schedule. The article analyses mathematical models, currently applied to forecast demand amounts and prices. It describes limits of time-series models and fundamental ones in case of hourly forecasting an irregular demand schedule of the electricity market entity. The features of electricity trading at WEM are carefully analysed. Factors that influence on irregularity of demand schedule of the metallurgical plant are shown. The article proposes method for the qualitative forecast of market price ratios as a tool to reduce a dependence on the accuracy of forecasting an irregular schedule of demand. It describes the differences between the offered method and the similar ones considered in research studies and scholarly works. The correlation between price ratios and relaxation in the requirements for the forecast accuracy of the electric power consumption is analysed. The efficiency function of forecast method is derived. The article puts an increased focus on description of the mathematical model based on the method of qualitative forecast. It shows main model parameters and restrictions the electricity market imposes on them. The model prototype is described as a programme module. Methods to assess an effectiveness of the proposed forecast model are examined. The positive test results of the model using JSC «Volzhsky Pipe Plant» data are given. A conclusion is drawn concerning the possibility to decrease dependence on the forecast accuracy of irregular schedule of entity’s demand at WEM. The effective trading tool has been found for the entities of irregular demand schedule at WEM. The tool application allows minimizing cost

Actors and factors in the governance of irregular migration : a comparative analysis of Albanian, Georgian, Ukrainian, Pakistani and Afghani irregular flows to Greece

OpenAIRE

TRIANDAFYLLIDOU, Anna

2015-01-01

Proceedings from the conference "Governing Irregular Migration : States, Actors and Intermediaries", Athens 8-9 July 2015 The loss of over a thousand human lives in the effort to cross the Mediterranean during April 2015 has once again drawn media and political attention to the challenges that the EU is facing in its efforts to govern migration and asylum. However, what seems to be still far from complete is our (the experts and the politicians) understanding of what drives people to put t...

An efficient algorithm for global periodic orbits generation near irregular-shaped asteroids

Science.gov (United States)

Shang, Haibin; Wu, Xiaoyu; Ren, Yuan; Shan, Jinjun

2017-07-01

Periodic orbits (POs) play an important role in understanding dynamical behaviors around natural celestial bodies. In this study, an efficient algorithm was presented to generate the global POs around irregular-shaped uniformly rotating asteroids. The algorithm was performed in three steps, namely global search, local refinement, and model continuation. First, a mascon model with a low number of particles and optimized mass distribution was constructed to remodel the exterior gravitational potential of the asteroid. Using this model, a multi-start differential evolution enhanced with a deflection strategy with strong global exploration and bypassing abilities was adopted. This algorithm can be regarded as a search engine to find multiple globally optimal regions in which potential POs were located. This was followed by applying a differential correction to locally refine global search solutions and generate the accurate POs in the mascon model in which an analytical Jacobian matrix was derived to improve convergence. Finally, the concept of numerical model continuation was introduced and used to convert the POs from the mascon model into a high-fidelity polyhedron model by sequentially correcting the initial states. The efficiency of the proposed algorithm was substantiated by computing the global POs around an elongated shoe-shaped asteroid 433 Eros. Various global POs with different topological structures in the configuration space were successfully located. Specifically, the proposed algorithm was generic and could be conveniently extended to explore periodic motions in other gravitational systems.

Comparison of the ballistic contractile responses generated during microstimulation of single human motor axons with brief irregular and regular stimuli.

Science.gov (United States)

Leitch, Michael; Macefield, Vaughan G

2017-08-01

Ballistic contractions are induced by brief, high-frequency (60-100 Hz) trains of action potentials in motor axons. During ramp voluntary contractions, human motoneurons exhibit significant discharge variability of ∼20% and have been shown to be advantageous to the neuromuscular system. We hypothesized that ballistic contractions incorporating discharge variability would generate greater isometric forces than regular trains with zero variability. High-impedance tungsten microelectrodes were inserted into human fibular nerve, and single motor axons were stimulated with both irregular and constant-frequency stimuli at mean frequencies ranging from 57.8 to 68.9 Hz. Irregular trains generated significantly greater isometric peak forces than regular trains over identical mean frequencies. The high forces generated by ballistic contractions are not based solely on high frequencies, but rather a combination of high firing rates and discharge irregularity. It appears that irregular ballistic trains take advantage of the "catchlike property" of muscle, allowing augmentation of force. Muscle Nerve 56: 292-297, 2017. © 2016 Wiley Periodicals, Inc.

A Highly Accurate Regular Domain Collocation Method for Solving Potential Problems in the Irregular Doubly Connected Domains

Directory of Open Access Journals (Sweden)

Zhao-Qing Wang

2014-01-01

Full Text Available Embedding the irregular doubly connected domain into an annular regular region, the unknown functions can be approximated by the barycentric Lagrange interpolation in the regular region. A highly accurate regular domain collocation method is proposed for solving potential problems on the irregular doubly connected domain in polar coordinate system. The formulations of regular domain collocation method are constructed by using barycentric Lagrange interpolation collocation method on the regular domain in polar coordinate system. The boundary conditions are discretized by barycentric Lagrange interpolation within the regular domain. An additional method is used to impose the boundary conditions. The least square method can be used to solve the overconstrained equations. The function values of points in the irregular doubly connected domain can be calculated by barycentric Lagrange interpolation within the regular domain. Some numerical examples demonstrate the effectiveness and accuracy of the presented method.

Health effects of exhaust particles

Energy Technology Data Exchange (ETDEWEB)

Pihlava, T.; Uuppo, M.; Niemi, S.

2013-11-01

This report introduces general information about diesel particles and their health effects. The purpose of this report is to introduce particulate matter pollution and present some recent studies made regarding the health effects of particulate matter. The aim is not to go very deeply into the science, but instead to keep the text understandable for the average layman. Particulate matter is a complex mixture of extremely small particles and liquid droplets. These small particles are made up of a number of components that include for example acids, such as nitrates and sulphates, as well as organic chemicals, metals and dust particles from the soil. Particulate matter comes from several sources, such as transportation emissions, industrial emissions, forest fires, cigarette smoke, volcanic ash and climate variations. Particles are divided into coarse particles with diameters less than 10 ..m, fine particles with diameters smaller than 2.5 ..m and ultra-fine particles with diameters less than 0.1 ..m. The particulate matter in diesel exhaust gas is a highly complex mixture of organic, inorganic, solid, volatile and partly volatile compounds. Many of these particles do not form until they reach the air. Many carcinogenic compounds have been found in diesel exhaust gas and it is considered carcinogenic to humans. Particulate matter can cause several health effects, such as premature death in persons with heart or lung disease, cancer, nonfatal heart attacks, irregular heartbeat, aggravated asthma, decreased lung function and an increase in respiratory symptoms, such as irritation of the airways, coughing or difficulty breathing. It is estimated that in Finland about 1300 people die prematurely due to particles and the economic loss in the EU due to the health effects of particles can be calculated in the billions. Ultra-fine particles are considered to be the most harmful to human health. Ultrafine particles usually make the most of their quantity and surface area

Spelling pronunciation and visual preview both facilitate learning to spell irregular words.

Science.gov (United States)

Hilte, Maartje; Reitsma, Pieter

2006-12-01

Spelling pronunciations are hypothesized to be helpful in building up relatively stable phonologically underpinned orthographic representations, particularly for learning words with irregular phoneme-grapheme correspondences. In a four-week computer-based training, the efficacy of spelling pronunciations and previewing the spelling patterns on learning to spell loan words in Dutch, originating from French and English, was examined in skilled and less skilled spellers with varying ages. Reading skills were taken into account. Overall, compared to normal pronunciation, spelling pronunciation facilitated the learning of the correct spelling of irregular words, but it appeared to be no more effective than previewing. Differences between training conditions appeared to fade with older spellers. Less skilled young spellers seemed to profit more from visual examination of the word as compared to practice with spelling pronunciations. The findings appear to indicate that spelling pronunciation and allowing a preview can both be effective ways to learn correct spellings of orthographically unpredictable words, irrespective of age or spelling ability.

Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

International Nuclear Information System (INIS)

Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du

2015-01-01

Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

Feasibility study of flexible phased array ultrasonic technology using irregular surface specimen

Energy Technology Data Exchange (ETDEWEB)

Lee, Seung Pyo; Moon, Yong Sik; Jung, Nam Du [NDE Performance Demonstration Team, Korea Hydro and Nuclear Power, Central Research Institute, Daejeon (Korea, Republic of)

2015-02-15

Nuclear power plant contain many dissimilar metal welds that connect carbon steel components with stainless steel pipes using alloy 600 welding materials. Primary water stress corrosion cracks at dissimilar metal welds have been continuously reported around the world. In periodic integrity evaluations, dissimilar metal welds are examined using a generic ultrasonic testing procedure, KPD-UT-10. In this procedure, the gap between the probe and examination surface is limited to 1/32 inch (0.8 mm). It is not easy to test some dissimilar metal welds in Korean plants applying ordinary technology because of their tapered shapes and irregular surface conditions. This paper introduces a method for applying a flexible phased array technology to improve the reliability of ultrasonic testing results for various shapes and surface conditions. The artificial flaws in specimens with irregular surfaces were completely detected using the flexible phased array ultrasonic technology. Therefore, it can be said that the technology is applicable to field examination.

Validation of AEGIS/SCOPE2 system through actual core follow calculations with irregular operational conditions

International Nuclear Information System (INIS)

Tabuchi, M.; Tatsumi, M.; Ohoka, Y.; Nagano, H.; Ishizaki, K.

2017-01-01

This paper describes overview of AEGIS/SCOPE2 system, an advanced in-core fuel management system for pressurized water reactors, and its validation results of actual core follow calculations including irregular operational conditions. AEGIS and SCOPE2 codes adopt more detailed and accurate calculation models compared to the current core design codes while computational cost is minimized with various techniques on numerical and computational algorithms. Verification and validation of AEGIS/SCOPE2 has been intensively performed to confirm validity of the system. As a part of the validation, core follow calculations have been carried out mainly for typical operational conditions. After the Fukushima Daiichi nuclear power plant accident, however, all the nuclear reactors in Japan suffered from long suspension and irregular operational conditions. In such situations, measured data in the restart and operation of the reactors should be good examinations for validation of the codes. Therefore, core follow calculations were carried out with AEGIS/SCOPE2 for various cases including zero power reactor physics tests with irregular operational conditions. Comparisons between measured data and predictions by AEGIS/SCOPE2 revealed the validity and robustness of the system. (author)

Irregular water supply, household usage and dengue: a bio-social study in the Brazilian Northeast.

Science.gov (United States)

Caprara, Andrea; Lima, José Wellington de Oliveira; Marinho, Alice Correia Pequeno; Calvasina, Paola Gondim; Landim, Lucyla Paes; Sommerfeld, Johannes

2009-01-01

Despite increased vector control efforts, dengue fever remains endemic in Fortaleza, Northeast Brazil, where sporadic epidemic outbreaks have occurred since 1986. Multiple factors affect vector ecology such as social policy, migration, urbanization, city water supply, garbage disposal and housing conditions, as well as community level understanding of the disease and related practices. This descriptive study used a multi-disciplinary approach that bridged anthropology and entomology. A multiple case study design was adopted to include research in six study areas, defined as blocks. The water supply is irregular in households from both under-privileged and privileged areas, however, clear differences exist. In the more privileged blocks, several homes are not connected to the public water system, but have a well and pump system and therefore irregularity of supply does not affect them. In households from under-privileged blocks, where the water supply is irregular, the frequent use of water containers such as water tanks, cisterns, barrels and pots, creates environmental conditions with a greater number of breeding areas. In under-privileged homes, there are more possible breeding areas and environmental conditions that may improve the chances of Aedes aegypti survival.

Evaluation of simplified two source model for relative electron output factor of irregular block shape

International Nuclear Information System (INIS)

Lo, Y. E.; Yi, B. Y.; Ahn, S. D.; Kim, J. H.; Lee, S. W.; Choi, E. K.

2002-01-01

A practical calculation algorithm which calculates the relative output factor (ROF) for electron irregular shaped-field has been developed and evaluated the accuracy and the effectiveness of the algorithm by comparing the measurements and the calculation results for irregular fields used in clinic. The algorithm assumes that the electron dose can be express as sum of the primary source component and the scattered component from the shielding block. The primary source is assumed to have Gaussian distribution, while the scattered component follows the inverse square law. Depth and angular dependency of the primary and the scattered are ignored for maximizing the practicability by reducing the number of parameters for the algorithm. Electron dose can be calculated with three parameters such as, the effective source distance, the variance of primary source, and the scattering power of the block. The coefficients are obtained from the square shaped-block measurements and these are confirmed from the rectangular or irregular shaped-fields. The results showed less than 1.5% difference between the calculation and measurements. The algorithm is proved to be practical, since one can acquire the full parameters with minimum measurements and generates accurate results within the clinically acceptable range

Electromagnetic waves in irregular multilayered spheroidal structures of finite conductivity: full wave solutions

International Nuclear Information System (INIS)

Bahar, E.

1976-01-01

The propagation of electromagnetic waves excited by electric dipoles oriented along the axis of multilayered spheroidal structures of finite conductivity is investigated. The electromagnetic parameters and the thickness of the layers of the structure are assumed to be functions of the latitude. In the analysis, electric and magnetic field transforms that constitute a discrete and a continuous spectrum of spherical waves are used to provide a suitable basis for the expansion of the electromagnetic fields at any point in the irregular spheroidal structure. For spheroidal structures with good conducting cores, the terms in the solutions associated with the continuous part of the wave spectrum vanish. In general, however, when the skin depth for the core is large compared to its dimensions or when the sources are located in the core of the structure and propagation in the core is of special interest, the contribution from the continuous part of the wave spectrum cannot be neglected. At each interface between the layers of the irregular spheroidal structure, exact boundary conditions are imposed. Since the terms of the field expansions in the irregular structure do not individually satisfy the boundary conditions, Maxwell's equations are reduced to sets of coupled ordinary first-order differential equations for the wave amplitudes. The solutions are shown to satisfy the reciprocity relationships in electromagnetic theory. The analysis may be applied to problems of radio wave propagation in a nonuniform model of the earth-ionosphere waveguide, particularly when focusing effects at the antipodes are important

On Impulsive Boundary Value Problems of Fractional Differential Equations with Irregular Boundary Conditions

Directory of Open Access Journals (Sweden)

Guotao Wang

2012-01-01

Full Text Available We study nonlinear impulsive differential equations of fractional order with irregular boundary conditions. Some existence and uniqueness results are obtained by applying standard fixed-point theorems. For illustration of the results, some examples are discussed.

Controllable irregular melting induced by atomic segregation in bimetallic clusters with fabricating different initial configurations

International Nuclear Information System (INIS)

Li Guojian; Liu Tie; Wang Qiang; Lue Xiao; Wang Kai; He Jicheng

2010-01-01

The melting process of Co, Co-Cu and Co-Ni clusters with different initial configurations is studied in molecular dynamics by a general embedded atom method. An irregular melting, at which energy decreases as the temperature increase near the melting point, is found in the onion-like Co-Cu-Co clusters, but not in the mixed Co-Cu and onion-like Co-Ni-Co clusters. From the analysis of atomic distributions and energy variation, the results indicate the irregular melting is induced by Cu atomic segregation. Furthermore, this melting can be controlled by doping hetero atoms with different surface energies and controlling their distributions.

Provision of health services to irregular migrants with a special focus on children.

Science.gov (United States)

Søvig, Karl Harald

2011-01-01

All European countries are now facing a situation where a part of the population consists of migrants without a permit to stay or reside. These persons may have health problems, and the question then rises regarding health services to irregular migrants. Normally, welfare benefits are offered those with a relationship to the country concerned, as citizen, asylum seeker, tourist, etc. Irregular migrants are outside the society, and it could be suggested that they therefore should be denied health services. On the other hand, common European standards of humanity lay obligations on the States, for example, where situations are life-threatening. This contribution gives an overview of relevant legal instruments, both from the UN, Council of Europe and the European Union. Although there are many similarities, the instruments have their differences, and there may even be some tensions regarding the underlying values.

Characterization of Nightside Mid-latitude Irregularities Observed with the Blackstone SuperDARN Radar

Science.gov (United States)

Ruohoniemi, J. M.; Ribeiro, A. J.; Baker, J. B.; Greenwald, R. A.; Newell, P. T.

2009-12-01

The new mid-latitude SuperDARN radars at Wallops Island and Blackstone observe strong coherent backscattering on an almost nightly basis from latitudes that appear to be subauroral. One study has demonstrated an excellent correlation with the occurrence of density and temperature gradients within the ionospheric projection of the plasmapause (Greenwald et al., Geophys. Res. Lett. [2006]). We have processed all the data collected with the Blackstone radar since its inception in February 2008 for a characterization of the occurrence and properties of ‘plasmapause’ scatter. We have determined the local time and Kp dependencies of the activity and the relation of the spatial distribution of the irregularities to magnetospheric boundaries and ionospheric density gradients. We establish that the irregularities are a feature of the quiet-time subauroral ionosphere and provide a valuable diagnostic of the electric fields in the inner magnetosphere.

A Hybrid Model Based on Wavelet Decomposition-Reconstruction in Track Irregularity State Forecasting

Directory of Open Access Journals (Sweden)

Chaolong Jia

2015-01-01

Full Text Available Wavelet is able to adapt to the requirements of time-frequency signal analysis automatically and can focus on any details of the signal and then decompose the function into the representation of a series of simple basis functions. It is of theoretical and practical significance. Therefore, this paper does subdivision on track irregularity time series based on the idea of wavelet decomposition-reconstruction and tries to find the best fitting forecast model of detail signal and approximate signal obtained through track irregularity time series wavelet decomposition, respectively. On this ideology, piecewise gray-ARMA recursive based on wavelet decomposition and reconstruction (PG-ARMARWDR and piecewise ANN-ARMA recursive based on wavelet decomposition and reconstruction (PANN-ARMARWDR models are proposed. Comparison and analysis of two models have shown that both these models can achieve higher accuracy.

Construction of theoretical F-spread ionogams from scattering in the HF band from field-aligned irregularities

International Nuclear Information System (INIS)

Powers, W.J.

1985-01-01

The scattering and propagation of electromagnetic fields in the ionosphere for the HF band is considered. Particular attention is given to scattering at the geomagnetic equator from irregularities of ionization density that are aligned along the earth's magnetic field and that have lengths that are much greater than a Fresnel scale. Perpendicular to the earth's magnetic field the irregularities are assumed to be isotropic with scale lengths (wavelengths /(2π)) extending from an inner scale equal to the ionic gyroradius to an outer scale on the order of the scale height of the ionosphere. Primary emphasis is placed on the weak scattering of pulses from field-aligned irregularities embedded in the night time F-layer, with application to explaining F-spread ionograms. The average ionization density of the night time F-layer is assumed to be well modeled by a parabolic layer. Assuming that the effects of the earth's magnetic field and collisions can be neglected, an approximate dyadic Green's function is derived and utilized in the determination of the incident and singly scattered fields

Nonadiabatic two-electron transfer mediated by an irregular bridge

International Nuclear Information System (INIS)

Petrov, E.G.; Shevchenko, Ye.V.; May, V.

2004-01-01

Nonadiabatic two-electron transfer (TET) mediated by a linear molecular bridge is studied theoretically. Special attention is put on the case of a irregular distribution of bridge site energies as well as on the inter-site Coulomb interaction. Based on the unified description of electron transfer reactions [J. Chem. Phys. 115 (2001) 7107] a closed set of kinetic equations describing the TET process is derived. A reduction of this set to a single exponential donor-acceptor (D-A) TET is performed together with a derivation of an overall D-A TET rate. The latter contains a contribution of the stepwise as well as of the concerted route of D-A TET. The stepwise contribution is determined by two single-electron steps each of them associated with a sequential and a superexchange pathway. A two-electron unistep superexchange transition between the D and A forms the concerted contribution to the overall rate. Both contributions are analyzed in their dependency on the bridge length. The irregular distribution of the bridge site energies as well as the influence of the Coulomb interaction facilitates the D-A TET via a modification of the stepwise and the concerted part of the overall rate. At low temperatures and for short bridges with a single or two units the concerted contribution exceeds the stepwise contribution. If the bridge contains more than two units, the stepwise contribution dominates the overall rate

Irregular water supply, household usage and dengue: a bio-social study in the Brazilian Northeast Abastecimento irregular de água, seu uso domiciliar e dengue: uma pesquisa biossocial no Nordeste do Brasil

Directory of Open Access Journals (Sweden)

Andrea Caprara

2009-01-01

Full Text Available Despite increased vector control efforts, dengue fever remains endemic in Fortaleza, Northeast Brazil, where sporadic epidemic outbreaks have occurred since 1986. Multiple factors affect vector ecology such as social policy, migration, urbanization, city water supply, garbage disposal and housing conditions, as well as community level understanding of the disease and related practices. This descriptive study used a multi-disciplinary approach that bridged anthropology and entomology. A multiple case study design was adopted to include research in six study areas, defined as blocks. The water supply is irregular in households from both under-privileged and privileged areas, however, clear differences exist. In the more privileged blocks, several homes are not connected to the public water system, but have a well and pump system and therefore irregularity of supply does not affect them. In households from under-privileged blocks, where the water supply is irregular, the frequent use of water containers such as water tanks, cisterns, barrels and pots, creates environmental conditions with a greater number of breeding areas. In under-privileged homes, there are more possible breeding areas and environmental conditions that may improve the chances of Aedes aegypti survival.Apesar do crescimento de esforços no controle, desde 1986, a dengue, em Fortaleza, Nordeste do Brasil, continua endêmica com esporádicos surtos epidêmicos. Diversos fatores influenciam a ecologia do vetor, como as políticas sociais, a migração, a urbanização, o abastecimento urbano de água, a coleta de resíduos sólidos, as condições das casas, assim como as interpretações e práticas da comunidade. Este estudo descritivo utiliza uma abordagem multidisciplinar conjugando a antropologia e a entomologia. Foi adotado um desenho de estudo de caso múltiplo em seis quarteirões da cidade. O abastecimento de água é irregular seja nas casas pobres, seja naquelas

Eddy current heating of irregularly shaped plates by slow ramped fields

International Nuclear Information System (INIS)

Dresner, L.

1979-01-01

Theorems are presented for estimating eddy current heating of irregularly shaped plates by a perpendicular ramped field. The theorems, which are derived from two complementary variational principles, give upper and lower bounds to the eddy current heating. Illustrative results are given for rectangles, isosceles triangles, sectors of circular annuli, rhombuses, and L-shaped plates. A comparison is made with earlier work

Toxicological effects of irregularly shaped and spherical microplastics in a marine teleost, the sheepshead minnow (Cyprinodon variegatus).

Science.gov (United States)

Choi, Jin Soo; Jung, Youn-Joo; Hong, Nam-Hui; Hong, Sang Hee; Park, June-Woo

2018-04-01

The increasing global contamination of plastics in marine environments is raising public concerns about the potential hazards of microplastics to environmental and human health. Microplastics formed by the breakdown of larger plastics are typically irregular in shape. The objective of this study was to compare the effects of spherical or irregular shapes of microplastics on changes in organ distribution, swimming behaviors, gene expression, and enzyme activities in sheepshead minnow (Cyprinodon variegatus). Both types of microplastics accumulated in the digestive system, causing intestinal distention. However, when compared to spherical microplastics, irregular microplastics decreased swimming behavior (i.e., total distance travelled and maximum velocity) of sheepshead minnow. Both microplastics generated cellular reactive oxygen species (ROS), while ROS-related molecular changes (i.e., transcriptional and enzymatic characteristics) differed. This study provides toxicological insights into the impacts of environmentally relevant (fragmented) microplastics on fish and improves our understanding of the environmental effects of microplastics in the ecosystem. Copyright © 2018 Elsevier Ltd. All rights reserved.

Massive stars in the Sagittarius Dwarf Irregular Galaxy

Science.gov (United States)

Garcia, Miriam

2018-02-01

Low metallicity massive stars hold the key to interpret numerous processes in the past Universe including re-ionization, starburst galaxies, high-redshift supernovae, and γ-ray bursts. The Sagittarius Dwarf Irregular Galaxy [SagDIG, 12+log(O/H) = 7.37] represents an important landmark in the quest for analogues accessible with 10-m class telescopes. This Letter presents low-resolution spectroscopy executed with the Gran Telescopio Canarias that confirms that SagDIG hosts massive stars. The observations unveiled three OBA-type stars and one red supergiant candidate. Pending confirmation from high-resolution follow-up studies, these could be the most metal-poor massive stars of the Local Group.

Systematic description of the effect of particle shape on the strength properties of granular media

Directory of Open Access Journals (Sweden)

Azéma Emilien

2017-01-01

Full Text Available In this paper, we explore numerically the effect of particle shape on the mechanical behavior of sheared granular packings. In the framework of the Contact Dynamic (CDMethod, we model angular shape as irregular polyhedral particles, non-convex shape as regular aggregates of four overlapping spheres, elongated shape as rounded cap rectangles and platy shape as square-plates. Binary granular mixture consisting of disks and elongated particles are also considered. For each above situations, the number of face of polyhedral particles, the overlap of spheres, the aspect ratio of elongated and platy particles, are systematically varied from spheres to very angular, non-convex, elongated and platy shapes. The level of homogeneity of binary mixture varies from homogenous packing to fully segregated packings. Our numerical results suggest that the effects of shape parameters are nonlinear and counterintuitive. We show that the shear strength increases as shape deviate from spherical shape. But, for angular shapes it first increases up to a maximum value and then saturates to a constant value as the particles become more angular. For mixture of two shapes, the strength increases with respect of the increase of the proportion of elongated particles, but surprisingly it is independent with the level of homogeneity of the mixture. A detailed analysis of the contact network topology, evidence that various contact types contribute differently to stress transmission at the micro-scale.

Penalized likelihood and multi-objective spatial scans for the detection and inference of irregular clusters

Directory of Open Access Journals (Sweden)

Fonseca Carlos M

2010-10-01

Full Text Available Abstract Background Irregularly shaped spatial clusters are difficult to delineate. A cluster found by an algorithm often spreads through large portions of the map, impacting its geographical meaning. Penalized likelihood methods for Kulldorff's spatial scan statistics have been used to control the excessive freedom of the shape of clusters. Penalty functions based on cluster geometry and non-connectivity have been proposed recently. Another approach involves the use of a multi-objective algorithm to maximize two objectives: the spatial scan statistics and the geometric penalty function. Results & Discussion We present a novel scan statistic algorithm employing a function based on the graph topology to penalize the presence of under-populated disconnection nodes in candidate clusters, the disconnection nodes cohesion function. A disconnection node is defined as a region within a cluster, such that its removal disconnects the cluster. By applying this function, the most geographically meaningful clusters are sifted through the immense set of possible irregularly shaped candidate cluster solutions. To evaluate the statistical significance of solutions for multi-objective scans, a statistical approach based on the concept of attainment function is used. In this paper we compared different penalized likelihoods employing the geometric and non-connectivity regularity functions and the novel disconnection nodes cohesion function. We also build multi-objective scans using those three functions and compare them with the previous penalized likelihood scans. An application is presented using comprehensive state-wide data for Chagas' disease in puerperal women in Minas Gerais state, Brazil. Conclusions We show that, compared to the other single-objective algorithms, multi-objective scans present better performance, regarding power, sensitivity and positive predicted value. The multi-objective non-connectivity scan is faster and better suited for the

Special Operations, Irregular Warfare, and Operational Art: A Theory of Special Operations

Science.gov (United States)

2013-12-10

is mostly but not wholly a land phenomenon. Naval forces have combatted maritime irregulars such as pirates for millennia, for example see: Plutarch ...SW2502SocialMediaAndUW.html (accessed June 15, 2013). Plaster, John L. SOG: Secret Wars of America’s Commandos in Vietnam. New York: Simon & Schuster, 1997. Plutarch

Bone conducted vibration selectively activates irregular primary otolithic vestibular neurons in the guinea pig.

Science.gov (United States)

Curthoys, Ian S; Kim, Juno; McPhedran, Samara K; Camp, Aaron J

2006-11-01

The main objective of this study was to determine whether bone-conducted vibration (BCV) is equally effective in activating both semicircular canal and otolith afferents in the guinea pig or whether there is preferential activation of one of these classes of vestibular afferents. To answer this question a large number (346) of single primary vestibular neurons were recorded extracellularly in anesthetized guinea pigs and were identified by their location in the vestibular nerve and classed as regular or irregular on the basis of the variability of their spontaneous discharge. If a neuron responded to angular acceleration it was classed as a semicircular canal neuron, if it responded to maintained roll or pitch tilts it was classified as an otolith neuron. Each neuron was then tested by BCV stimuli-either clicks, continuous pure tones (200-1,500 Hz) or short tone bursts (500 Hz lasting 7 ms)-delivered by a B-71 clinical bone-conduction oscillator cemented to the guinea pig's skull. All stimulus intensities were referred to that animal's own auditory brainstem response (ABR) threshold to BCV clicks, and the maximum intensity used was within the animal's physiological range and was usually around 70 dB above BCV threshold. In addition two sensitive single axis linear accelerometers cemented to the skull gave absolute values of the stimulus acceleration in the rostro-caudal direction. The criterion for a neuron being classed as activated was an audible, stimulus-locked increase in firing rate (a 10% change was easily detectable) in response to the BCV stimulus. At the stimulus levels used in this study, semicircular canal neurons, both regular and irregular, were insensitive to BCV stimuli and very few responded: only nine of 189 semicircular canal neurons tested (4.7%) showed a detectable increase in firing in response to BCV stimuli up to the maximum 2 V peak-to-peak level we delivered to the B-71 oscillator (which produced a peak-to-peak skull acceleration of around

Sedimentation of bidisperse, uncharged colloidal sphere suspensions: Influence of viscosity and irregular surfaces

NARCIS (Netherlands)

Thies-Weesie, Dominique M. E.; Philipse, Albert P.; Lekkerkerker, Henk N. W.

1996-01-01

The sedimentation velocity of uncharged, nonaggregated silica spheres under gravity is strongly reduced after addition of small amounts of nonsedimenting small spheres. This reduction is largely due to surface irregularities on a nanoscale of the large spheres at which a limited number of small

Menarche delay and menstrual irregularities persist in adolescents with type 1 diabetes

Directory of Open Access Journals (Sweden)

McFann Kim

2011-05-01

Full Text Available Abstract Background Menarche delay has been reported in adolescent females with type 1 diabetes (T1DM, perhaps due to poor glycemic control. We sought to compare age at menarche between adolescent females with T1DM and national data, and to identify factors associated with delayed menarche and menstrual irregularity in T1DM. Methods This was a cross-sectional study and females ages 12- 24 years (n = 228 with at least one menstrual period were recruited during their outpatient diabetes clinic appointment. The National Health and Nutrition Examination Survey (NHANES 2001-2006 data (n = 3690 for females 12-24 years were used as a control group. Results Age at menarche was later in adolescent females with T1DM diagnosed prior to menarche (12.81 +/- 0.09 years (mean+/- SE (n = 185 than for adolescent females diagnosed after menarche (12.17 0.19 years, p = 0.0015 (n = 43. Average age of menarche in NHANES was 12.27 +/- 0.038 years, which was significantly earlier than adolescent females with T1DM prior to menarche (p p = 0.77. Older age at menarche was negatively correlated with BMI z-score (r = -0.23 p = 0.0029 but not hemoglobin A1c (A1c at menarche (r = 0.01, p = 0.91. Among 181 adolescent females who were at least 2 years post menarche, 63 (35% reported usually or always irregular cycles. Conclusion Adolescent females with T1DM had a later onset of menarche than both adolescent females who developed T1DM after menarche and NHANES data. Menarche age was negatively associated with BMI z-score, but not A1c. Despite improved treatment in recent decades, menarche delay and high prevalence of menstrual irregularity is still observed among adolescent females with T1DM.

Report of the advisory group meeting on the utilization of particle accelerators for proton therapy

International Nuclear Information System (INIS)

1998-07-01

Accelerated protons and light ions, being electrically charged and much heavier than electrons, have definite ranges in tissue with distinct Bragg peak with sharp distal falloffs and sharp lateral dose penumbra. Radiations oncologists could take advantage of these characteristics to deposit a high dose in an irregularly shaped tumor volume while sparing the surrounding healthy tissues and critical organs. This could lead to enhanced tumor control with reduced complications. The Advisory Group has recommended a number of measures to promote and support the spread of medically dedicated particle accelerator facilities and technology

An Optimization Algorithm for the Design of an Irregularly-Shaped Bridge Based on the Orthogonal Test and Analytic Hierarchy Process

Directory of Open Access Journals (Sweden)

Hanbing Liu

2016-11-01

Full Text Available Irregularly-shaped bridges are usually adopted to connect the main bridge and ramps in urban overpasses, which are under significant flexion-torsion coupling effects and in complicated stress states. In irregular-shaped bridge design, the parameters such as ramp radius, bifurcation diaphragm stiffness, box girder height, and supporting condition could affect structural performance in different manners. In this paper, the influence of various parameters on three indices, including maximum stress, the stress variation coefficient, and the fundamental frequency of torsional vibration, is investigated and analyzed based on orthogonal test method. Through orthogonal analysis, the major influence parameters and corresponding optimal values for these indices are achieved. Combining with the analytic hierarchy process (AHP, the hierarchical structure model of the multi-indices orthogonal test is established and a comprehensive weight analysis method is proposed to reflect the parameter influence on overall mechanical properties of an irregularly-shaped bridge. Influence order and optimal values of parameters for overall mechanical properties are determined based on the weight of factors and levels calculated by the comprehensive weight analysis method. The results indicate that the comprehensive weight analysis method is superior to the overall balance method, which verifies the effectiveness and accuracy of the comprehensive weight analysis in the parameter optimization of the multi-indices orthogonal test for an irregularly-shaped bridge. Optimal parameters obtained in this paper can provide reference and guidance for parameter control in irregularly-shaped bridge design.

The calculation of relative output factor and depth dose for irregular electron fields in water

International Nuclear Information System (INIS)

Dunscombe, Peter; McGhee, Peter; Chu, Terence

1996-01-01

Purpose: A technique, based on sector integration and interpolation, has been developed for the computation of both relative output factor and depth dose of irregular electron fields in water. The purpose of this study was to determine the minimum experimental data set required for the technique to yield results within accepted dosimetric tolerances. Materials and Methods: PC based software has been written to perform the calculations necessary to dosimetrically characterize irregular shaped electron fields. The field outline is entered via digitiser and the SSD and energy via the keyboard. The irregular field is segmented into sectors of specified angle (2 deg. was used for this study) and the radius of each sector computed. The central ray depth dose is reconstructed by summing the contributions from each sector deduced from calibration depth doses measured for circular fields. Relative output factors and depth doses at SSDs at which calibrations were not performed are found by interpolation. Calibration data were measured for circular fields from 2 to 9 cm diameter at 100, 105, 110, and 115 cm SSD. A clinical cut out can be characterized in less than 2 minutes including entry of the outline using this software. The performance of the technique was evaluated by comparing calculated relative output factors, surface dose and the locations of d 80 , d 50 and d 20 with experimental measurements on a variety of cut out shapes at 9 and 18 MeV. The calibration data set (derived from circular cut outs) was systematically reduced to identify the minimum required to yield an accuracy consistent with current recommendations. Results: The figure illustrates the ability of the technique to calculate the depth dose for an irregular field (shown in the insert). It was found that to achieve an accuracy of 2% in relative output factor and 2% or 2 mm (our criterion) in percentage depth dose, calibration data from five circular fields at the four SSDs spanning the range 100-115 cm

Computation of stress on the surface of a soft homogeneous arbitrarily shaped particle.

Science.gov (United States)

Yang, Minglin; Ren, Kuan Fang; Wu, Yueqian; Sheng, Xinqing

2014-04-01

Prediction of the stress on the surface of an arbitrarily shaped particle of soft material is essential in the study of elastic properties of the particles with optical force. It is also necessary in the manipulation and sorting of small particles with optical tweezers, since a regular-shaped particle, such as a sphere, may be deformed under the nonuniform optical stress on its surface. The stress profile on a spherical or small spheroidal soft particle trapped by shaped beams has been studied, however little work on computing the surface stress of an irregular-shaped particle has been reported. We apply in this paper the surface integral equation with multilevel fast multipole algorithm to compute the surface stress on soft homogeneous arbitrarily shaped particles. The comparison of the computed stress profile with that predicted by the generalized Lorenz-Mie theory for a water droplet of diameter equal to 51 wavelengths in a focused Gaussian beam show that the precision of our method is very good. Then stress profiles on spheroids with different aspect ratios are computed. The particles are illuminated by a Gaussian beam of different waist radius at different incidences. Physical analysis on the mechanism of optical stress is given with help of our recently developed vectorial complex ray model. It is found that the maximum of the stress profile on the surface of prolate spheroids is not only determined by the reflected and refracted rays (orders p=0,1) but also the rays undergoing one or two internal reflections where they focus. Computational study of stress on surface of a biconcave cell-like particle, which is a typical application in life science, is also undertaken.

PERLINDUNGAN HUKUM BAGI IRREGULAR MIGRANT WORKERS INDONESIA DI KAWASAN ASIA TENGGARA (DALAM PERSPEKTIF HUKUM HAM INTERNASIONAL

Directory of Open Access Journals (Sweden)

Riri Anggriani

2017-05-01

Full Text Available The development of globalization that occurred has considerable impact for human life and for countries in Southeast Asia. One is the movement of people from one country to another, especially concerning the problem of economic migrants seeking employment or working in a country where they work especially irregular migrant workers. These irregular migrants are vulnerable to violations of their human rights. The issue is how the protection of the law is provided by the country of origin through Indonesian national law in countries that are the destination of Indonesian migrant workers in the Southeast Asian Region through the perspective of international human rights law. This research is legal research. The results of this study indicate that Indonesian migrant workers with the status of irregular migrant workers are workers who also have the same rights as other migrant workers or other citizens so that countries (especially countries in Southeast Asia have an obligation to acknowledge and Protect them wherever they may be or under any circumstances they experience as contained in the provisions of international human rights law, especially in the Convention on the Protection of the Rights of All Migrant Workers and their Families (CMW, 1990.

ESA' s novel gravitational modeling of irregular planetary bodies

Science.gov (United States)

Ortega, Guillermo

A detailed understanding and modeling of the gravitational modeling is required for realistic investigation of the dynamics of orbits close to irregularly shaped bodies. Gravity field modelling up to a certain maximum spherical harmonic degree N involves N2 unkown spherical harmonic coefficients or complex harmonics. The corresponding number of matrix entries reaches till N4 . For missions like CHAMP, GRACE or GOCE, the maximum degree of resolution is 75, 150 and 300 respectively. Therefore, the number of unknowns for a satellite like GOCE will be around 100.000. Since these missions usually fly for a period of time of several years, the number of observations is huge. Hence, gravity field recovery from these missions is a high demanding task. The classical approaches like spherical expansion of the potential lead generally to a high number of coefficients, which reduce the software computational efficiency of the orbit propagation and which have mostly a limited physical meaning. One of the main targets of the activity is the modelling of asteroids, small moons, and cometary bodies. All celestial bodies are irregular by definition. However, the scope of the activity is broad enough as to be able to use the models and the software in quasy-regular bodies as well. Therefore the models and tools could be used for bodies such as the Moon, Mars, Venus, Deimos, Europa, Eros, Mathilda, and Churyumov-Gerasimenko, etc., being these applications relevant for scientific (Rosetta, Bepi Colombo), exploration (Exo-Mars), NEO mitigation (Don Quijote) and Earth observation (GOCE) missions of ESA.

Method for hot pressing irregularly shaped refractory articles

Science.gov (United States)

Steinkamp, William E.; Ballard, Ambrose H.

1982-01-01

The present invention is directed to a method for hot pressing irregularly haped refractory articles with these articles of varying thickness being provided with high uniform density and dimensional accuracy. Two partially pressed compacts of the refractory material are placed in a die cavity between displaceable die punches having compact-contacting surfaces of the desired article configuration. A floating, rotatable block is disposed between the compacts. The displacement of the die punches towards one another causes the block to rotate about an axis normal to the direction of movement of the die punches to uniformly distribute the pressure loading upon the compacts for maintaining substantially equal volume displacement of the powder material during the hot pressing operation.

Computing Homology Group Generators of Images Using Irregular Graph Pyramids

OpenAIRE

Peltier , Samuel; Ion , Adrian; Haxhimusa , Yll; Kropatsch , Walter; Damiand , Guillaume

2007-01-01

International audience; We introduce a method for computing homology groups and their generators of a 2D image, using a hierarchical structure i.e. irregular graph pyramid. Starting from an image, a hierarchy of the image is built, by two operations that preserve homology of each region. Instead of computing homology generators in the base where the number of entities (cells) is large, we first reduce the number of cells by a graph pyramid. Then homology generators are computed efficiently on...

Threshold Multi Split-Row algorithm for decoding irregular LDPC codes

Directory of Open Access Journals (Sweden)

Chakir Aqil

2017-12-01

Full Text Available In this work, we propose a new threshold multi split-row algorithm in order to improve the multi split-row algorithm for LDPC irregular codes decoding. We give a complete description of our algorithm as well as its advantages for the LDPC codes. The simulation results over an additive white gaussian channel show that an improvement in code error performance between 0.4 dB and 0.6 dB compared to the multi split-row algorithm.

Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures

Energy Technology Data Exchange (ETDEWEB)

Sevastianov, L. A., E-mail: sevast@sci.pfu.edu.ru [Peoples' Friendship University of Russia (Russian Federation); Egorov, A. A. [Russian Academy of Sciences, Prokhorov General Physics Institute (Russian Federation); Sevastyanov, A. L. [Peoples' Friendship University of Russia (Russian Federation)

2013-02-15

Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell's equations is made to obey 'inclined' boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of 'entanglement' of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lueneburg lens.

Method of adiabatic modes in studying problems of smoothly irregular open waveguide structures

International Nuclear Information System (INIS)

Sevastianov, L. A.; Egorov, A. A.; Sevastyanov, A. L.

2013-01-01

Basic steps in developing an original method of adiabatic modes that makes it possible to solve the direct and inverse problems of simulating and designing three-dimensional multilayered smoothly irregular open waveguide structures are described. A new element in the method is that an approximate solution of Maxwell’s equations is made to obey “inclined” boundary conditions at the interfaces between themedia being considered. These boundary conditions take into account the obliqueness of planes tangent to nonplanar boundaries between the media and lead to new equations for coupled vector quasiwaveguide hybrid adiabatic modes. Solutions of these equations describe the phenomenon of “entanglement” of two linear polarizations of an irregular multilayered waveguide, the appearance of a new mode in an entangled state, and the effect of rotation of the polarization plane of quasiwaveguide modes. The efficiency of the method is demonstrated by considering the example of numerically simulating a thin-film generalized waveguide Lüneburg lens.

Inter-hospital Cross-validation of Irregular Discharge Patterns for Young vs. Old Psychiatric Patients

Science.gov (United States)

Mozdzierz, Gerald J.; Davis, William E.

1975-01-01

Type of discharge (irregular vs. regular) and length of time hospitalized were used as unobtrusive measures of psychiatric patient acceptance of hospital treatment regime among two groups (18-27 years and 45 years and above) of patients. (Author)

Effect of silica particles modified by in-situ and ex-situ methods on the reinforcement of silicone rubber

International Nuclear Information System (INIS)

Song, Yingze; Yu, Jinhong; Dai, Dan; Song, Lixian; Jiang, Nan

2014-01-01

Highlights: • In-situ and ex-situ methods were applied to modify silica particles. • In-situ method was more beneficial to preparing silica particles with high BET surface area. • Silicone rubber filled with in-situ modified silica exhibits excellent mechanical and thermal properties. - Abstract: In-situ and ex-situ methods were applied to modify silica particles in order to investigate their effects on the reinforcement of silicone rubber. Surface area and pore analyzer, laser particle size analyzer, Fourier-transform infrared spectroscopy (FTIR), contact-angle instrument, and transmission electron microscope (TEM) were utilized to investigate the structure and properties of the modified silica particles. Dynamic mechanical thermal analyzer (DMTA) was employed to characterize the vulcanizing behavior and mechanical properties of the composites. Thermogravimetric analysis (TGA) was performed to test the thermal stability of the composites. FTIR and contact angle analysis indicated that silica particles were successfully modified by these two methods. The BET surface area and TEM results reflected that in-situ modification was more beneficial to preparing silica particles with irregular shape and higher BET surface area in comparison with ex-situ modification. The DMTA and TGA data revealed that compared with ex-situ modification, the in-situ modification produced positive influence on the reinforcement of silicone rubber

Numerical investigation of the energy performance of a guideless irregular heat and mass exchanger with corrugated heat transfer surface for dew point cooling

International Nuclear Information System (INIS)

Xu, Peng; Ma, Xiaoli; Diallo, Thierno M.O.; Zhao, Xudong; Fancey, Kevin; Li, Deying; Chen, Hongbing

2016-01-01

The paper presents an investigation into the energy performance of a novel irregular heat and mass exchanger for dew point cooling which, compared to the existing flat-plate heat exchangers, removed the use of the channel supporting guides and implemented the corrugated heat transfer surface, thus expecting to achieve the reduced air flow resistance, increased heat transfer area, and improved energy efficiency (i.e. Coefficient of Performance (COP)) of the air cooling process. CFD simulation was carried out to determine the flow resistance (K) factors of various elements within the dry and wet channels of the exchanger, while the ‘finite-element’ based ‘Newton-iteration’ numerical simulation was undertaken to investigate its cooling capacity, cooling effectiveness and COP at various geometrical and operational conditions. Compared to the existing flat-plate heat and mass exchangers with the same geometrical dimensions and operational conditions, the new irregular exchanger could achieve 32.9%–37% higher cooling capacity, dew-point and wet-bulb effectiveness, 29.7%–33.3% higher COP, and 55.8%–56.2% lower pressure drop. While undertaking dew point air cooling, the irregular heat and mass exchanger had the optimum air velocity of 1 m/s within the flow channels and working-to-intake air ratio of 0.3, which allowed the highest cooling capacity and COP to be achieved. In terms of the exchanger dimensions, the optimum height of the channel was 5 mm while its length was in the range 1–2 m. Overall, the proposed irregular heat and mass exchanger could lead to significant enhanced energy performance compared to the existing flat-plate dew point cooling heat exchanger of the same geometrical dimensions. To achieve the same amount cooling output, the irregular heat and mass exchanger had the reduced size and cost against the flat-plate ones. - Highlights: • Numerical investigation of an irregular heat and mass exchanger was undertaken. • A �

An adaptive vibration control method to suppress the vibration of the maglev train caused by track irregularities

Science.gov (United States)

Zhou, Danfeng; Yu, Peichang; Wang, Lianchun; Li, Jie

2017-11-01

The levitation gap of the urban maglev train is around 8 mm, which puts a rather high requirement on the smoothness of the track. In practice, it is found that the track irregularity may cause stability problems when the maglev train is traveling. In this paper, the dynamic response of the levitation module, which is the basic levitation structure of the urban maglev train, is investigated in the presence of track irregularities. Analyses show that due to the structural configuration of the levitation module, the vibration of the levitation gap may be amplified and "resonances" may be observed under some specified track wavelengths and train speeds; besides, it is found that the gap vibration of the rear levitation unit in a levitation module is more significant than that of the front levitation unit, which agrees well with practice. To suppress the vibration of the rear levitation gap, an adaptive vibration control method is proposed, which utilizes the information of the front levitation unit as a reference. A pair of mirror FIR (finite impulse response) filters are designed and tuned by an adaptive mechanism, and they produce a compensation signal for the rear levitation controller to cancel the disturbance brought by the track irregularity. Simulations under some typical track conditions, including the sinusoidal track profile, random track irregularity, as well as track steps, indicate that the adaptive vibration control scheme can significantly reduce the amplitude of the rear gap vibration, which provides a method to improve the stability and ride comfort of the maglev train.

Accuracy limits of the equivalent field method for irregular photon fields

International Nuclear Information System (INIS)

Sanz, Dario Esteban

2002-01-01

A mathematical approach is developed to evaluate the accuracy of the equivalent field method using basic clinical photon beam data. This paper presents an analytical calculation of dose errors arising when field equivalencies, calculated at a certain reference depth, are translated to other depths. The phantom scatter summation is expressed as a Riemann-Stieltjes integral and two categories of irregular fields are introduced: uniform and multiform. It is shown that multiform fields produce errors whose magnitudes are nearly twice those corresponding to uniform fields in extreme situations. For uniform field shapes, the maximum, local, relative dose errors, when the equivalencies are calculated at 10 cm depth on the central axis and translated to a depth of 30 cm, are 3.8% and 8.8% for 6 MV and cobalt-60 photon beams, respectively. In terms of maximum dose those errors are within 1-2%. This supports the conclusion that the equivalencies between rectangular fields, which are examples of uniform fields, are applicable to dose ratio functions irrespective of beam energy. However, the magnitude of such errors could be of importance when assessing the exit dose for in vivo monitoring. This work provides a better understanding of the influence of the irregular field shapes on the accuracy of the equivalent field method. (author)

Study of the spheroidization process of glass particles for selective internal radiotherapy

International Nuclear Information System (INIS)

Barros Filho, Eraldo Cordeiro

2012-01-01

The selective internal radiotherapy is an alternative method to treat hepatocellular carcinoma. Glass microspheres containing radionuclides are introduced in the liver through the hepatic artery, and they are housed preferentially in the region where the cancer cells are located. The microspheres are trapped in the arterioles which feed the tumors, and the β - particles annihilate the cancer cells. When these particles simultaneously emit γ rays, they can also be used to provide images of the tumor. The glass particles must be spherical to avoid unnecessary bleeding, and the particle size must be restricted to a range which is appropriated to trap them and avoid the migration to other parts of the body. Furthermore, they must have a good chemical durability and be nontoxic. The particle size distribution of microspheres is not easily predicted based on the original irregular particles since the variation of the aspect ratio and the presence of agglomerates can influence the final result. In the present work, the spheroidization process to obtain microspheres for radiotherapy treatment was studied. The glass microspheres were characterized by X-rays diffraction, Energy Dispersive X-rays Fluorescence Spectroscopy, Differential Scanning Calorimetry, Specific Superficial Area and cytotoxicity test. The dissolution rate in distilled water at 90 degree C (DR∼10 -8 g.cm - 2.min -1 ), density (2.79g.cm -3 ), viscosity, and size particle distribution were determined. The surface morphological aspect was evaluated by Scanning Electron Microscopy before and after the chemical durability tests in SBF and after the neutron irradiation. It is proposed that the produced material should be sieved to select the most suitable microspheres

Irregular wave functions of a hydrogen atom in a uniform magnetic field

Science.gov (United States)

Wintgen, D.; Hoenig, A.

1989-01-01

The highly excited irregular wave functions of a hydrogen atom in a uniform magnetic field are investigated analytically, with wave function scarring by periodic orbits considered quantitatively. The results obtained confirm that the contributions of closed classical orbits to the spatial wave functions vanish in the semiclassical limit. Their disappearance, however, is slow. This discussion is illustrated by numerical examples.

Effect of pH value on particle morphology and electrochemical properties of LiFePO4 by hydrothermal method

International Nuclear Information System (INIS)

Song, Qingzhu; Ou, Xiuqin; Wang, Li; Liang, Guangchuan; Wang, Zuorui

2011-01-01

Graphical abstract: The pH value of system is adjusted in the range of 2.5-8.8 by using dilute sulfuric acid and ammonia water. The results indicated that the particle exhibits acute angle diamond flake-like morphology at pH = 2.5. With increase of pH value, the particle gradually becomes to round flake-like and irregular flake-like morphology. The optimal sample synthesized at pH = 6.4 exhibits discharge capacities of 151.8 mAh g -1 at 0.2 C rate and 129.3 mAh g -1 at 3 C rate. Highlights: → The pH value of solution affects greatly on particle morphology. → The solubility product determined the transition of interphases. → The disorder of atoms in crystal is affected by pH value. → LiFePO 4 with high capacity could be synthesized at slight acid or neutral conditions. -- Abstract: Lithium iron phosphate was prepared by hydrothermal synthesis using LiOH.H 2 O, FeSO 4 .7H 2 O and H 3 PO 4 as raw materials. The effects of pH value of reaction solution on particle morphology and electrochemical property were investigated. The pH value of the reaction solution was adjusted in the range of 2.5-8.8 by dilute sulfuric acid and ammonia water. The samples were characterized by field-emission scanning electronic microscope (FE-SEM), X-ray powder diffraction (XRD), constant-current charge/discharge cycling tests and chemical analysis. The results indicated that the particles exhibited acute angle diamond flake-like morphology at pH = 2.5, and as the pH value increased, the particle became hexagon flake-like, round flake-like and irregular flake-like morphology gradually. The optimal sample synthesized at pH = 6.4 exhibited discharge capacities of 151.8 mAh g -1 at 0.2 C rate and 129.3 mAh g -1 at 3 C rate. It was found that pH value affected the morphologies and properties of the product by means of different crystal growth rates.

Irregular radiation response of a chondrosarcoma

International Nuclear Information System (INIS)

Marsden, J.J.; Kember, N.F.; Shaw, J.E.H.

1980-01-01

The DC II mouse chondrosarcoma was shown to be a potentially valuable radiobiological tumour system since it recovered from radiation injury by regrowth from clones that could be counted in histological sections. Unfortunately, the normal growth of this tumour following s.c. implantation in the thigh was irregular both in the time before growth became evident and in the rate of growth. The response to radiation was also unreliable since tumours irradiated with the same dose (e.g. 30 Gy) showed a range of responses from shrinkage to no detectable change in growth rate. The delay in normal growth can be attributed largely to delays in vascularization while changes in growth rate may be explained by differences in tumour architecture. Radiation response may depend on variations in hypoxic fraction and in relative cellularity. Tumours having the same external dimensions may differ by a factor of 80 in the numbers of tumour cells they contain. This chondrosarcoma may prove a closer model to some human tumours than many transplantable tumours that display regular growth patterns. (author)

Particle engineering using sonocrystallization: salbutamol sulphate for pulmonary delivery.

Science.gov (United States)

Dhumal, Ravindra S; Biradar, Shailesh V; Paradkar, Anant R; York, Peter

2009-02-23

The aim of present work was to produce fine elongated crystals of salbutamol sulphate (SS) by sonocrystallization for pulmonary delivery and compare with micronized and spray dried SS (SDSS) for in vitro aerosolization behavior. Application of ultrasound during anti-solvent crystallization resulted in fine elongated crystals (sonocrystallized SS; SCSS) compared to aggregates of large irregular crystals obtained without sonication. Higher sonication amplitude, time, concentration and lower processing temperatures favored formation of smaller crystals with narrow particle size distribution (PSD). SCSS was separated from dispersion by spray drying in the form of loose aggregates (SD-SCSS). The fine particle fraction (FPF) of formulations with coarse lactose carrier in cascade impactor increased from 16.66% for micronized SS to 31.12% for SDSS (obtained by spray drying aqueous SS solution) and 44.21% for SD-SCSS, due to reduced cohesive/adhesive forces and aerodynamic size by virtue of elongated shape of crystals. SD-SCSS was stable without any change in crystallinity and aerodynamic behavior for 3 months at 40 degrees C/75% RH, but amorphous SDSS showed recrystallization with poor aerosolization performance on storage. Sonocrystallization, a rapid and simple technique is reported for production of SS crystals suitable for inhalation delivery.

Spherical and irregular aberrations are important for the optimal performance of the human eye

NARCIS (Netherlands)

Nio, YK; Jansonius, NM; Fidler, [No Value; Geraghty, E; Norrby, S; Kooijman, AC

Contrast sensitivity measured psychophysically at different levels of defocus can be used to evaluate the eye optics. Possible parameters of spherical and irregular aberrations, e.g, relative modulation transfer (RMT), myopic shift, and depth of focus, can be determined from these measurements. The

Size and Albedo of Irregular Saturnian Satellites from Spitzer Observations

Science.gov (United States)

Mueller, Michael; Grav, T.; Trilling, D.; Stansberry, J.; Sykes, M.

2008-09-01

Using MIPS onboard the Spitzer Space Telescope, we observed the thermal emission (24 and, for some targets, 70 um) of eight irregular satellites of Saturn: Albiorix, Siarnaq, Paaliaq, Kiviuq, Ijiraq, Tarvos, Erriapus, and Ymir. We determined the size and albedo of all targets. An analysis of archived MIPS observations of Phoebe reproduces Cassini results very accurately, thereby validating our method. For all targets, the geometric albedo is found to be low, probably below 10% and clearly below 15%. Irregular satellites are much darker than the large regular satellites. Their albedo is, however, quite similar to that of small bodies in the outer Solar System (such as cometary nuclei, Jupiter Trojans, or TNOs). This is consistent with color measurements as well as dynamical considerations which suggest a common origin of the said populations. There appear to be significant object-to-object albedo differences. Similar albedos found for some members of dynamical clusters support the idea that they may have originated in the breakup of a parent body. For three satellites, thermal data at two wavelengths are available, enabling us to constrain their thermal properties. Sub-solar temperatures are similar to that found from Cassini's Phoebe fly-by. This suggests a rather low thermal inertia, as expected for regolith-covered objects. This work is based on observations made with the Spitzer Space Telescope, which is operated by JPL under a contract with NASA. Support for this work was provided by NASA.

Experimental Study of Irregular Waves on a Gravel Beach

Science.gov (United States)

Hu, Nai-Ren; Wu, Yun-Ta; Hwung, Hwung-Hweng; Yang, Ray-Yeng

2017-04-01

In the east coast of Taiwan, the sort grain size more belongs to cobble or gravel, which is physically distinct compared to the sandy beach in the west coast of Taiwan. Although gravel beaches can dissipate more of wave energy, gravel beaches were eroded and coastal road were damaged especially during typhoons. The purpose of this study is to investigate the geomorphological response of gravel beach due to irregular waves. This experiment was carry out in a 21m long, 50 cm wide, 70 cm high wave tank at Tainan Hydraulics Laboratory, National Cheng-Kung University, Taiwan. To simulate of the geometry in the east coast of Taiwan, a physical model with 1/36 scale-down was used, in which the seawall was 10cm built upon a 1:10 slope and gravel grains with D50 being 3.87 mm was nourished in front of the seawall. In terms of typhoon-scale wave condition, irregular waves with scale-down conditions were generated for 600 s for each scenarios and, three different water levels with respect to the gravel beach are designed. Application of laser combined with image processing to produce 3D topographic map, the erosion zone and accretion zone would be found. The resulting morphological change of gravel beach will be measured using an integrated laser and image processing tool to have 3D topographic maps. It is expected to have more understanding about under what conditions the gravel coasts suffer the least damage. In particular, the relation between erosion rates of gravel beach, the angle of gravel slope and the length of the plane on the gravel slope will be achieved

Mei symmetry and conservation laws of discrete nonholonomic dynamical systems with regular and irregular lattices

International Nuclear Information System (INIS)

Zhao Gang-Ling; Chen Li-Qun; Fu Jing-Li; Hong Fang-Yu

2013-01-01

In this paper, Noether symmetry and Mei symmetry of discrete nonholonomic dynamical systems with regular and the irregular lattices are investigated. Firstly, the equations of motion of discrete nonholonomic systems are introduced for regular and irregular lattices. Secondly, for cases of the two lattices, based on the invariance of the Hamiltomian functional under the infinitesimal transformation of time and generalized coordinates, we present the quasi-extremal equation, the discrete analogues of Noether identity, Noether theorems, and the Noether conservation laws of the systems. Thirdly, in cases of the two lattices, we study the Mei symmetry in which we give the discrete analogues of the criterion, the theorem, and the conservative laws of Mei symmetry for the systems. Finally, an example is discussed for the application of the results

Reconstruction in PET cameras with irregular sampling and depth of interaction capability

International Nuclear Information System (INIS)

Virador, P.R.G.; Moses, W.W.; Huesman, R.H.

1998-01-01

The authors present 2D reconstruction algorithms for a rectangular PET camera capable of measuring depth of interaction (DOI). The camera geometry leads to irregular radial and angular sampling of the tomographic data. DOI information increases sampling density, allowing the use of evenly spaced quarter-crystal width radial bins with minimal interpolation of irregularly spaced data. In the regions where DOI does not increase sampling density (chords normal to crystal faces), fine radial sinogram binning leads to zero efficiency bins if uniform angular binning is used. These zero efficiency sinogram bins lead to streak artifacts if not corrected. To minimize these unnormalizable sinogram bins the authors use two angular binning schemes: Fixed Width and Natural Width. Fixed Width uses a fixed angular width except in the problem regions where appropriately chosen widths are applied. Natural Width uses angle widths which are derived from intrinsic detector sampling. Using a modified filtered-backprojection algorithm to accommodate these angular binning schemes, the authors reconstruct artifact free images with nearly isotropic and position independent spatial resolution. Results from Monte Carlo data indicate that they have nearly eliminated image degradation due to crystal penetration

Lattice gas automaton scheme with stochastic particle movement for a rotated fluid flow

International Nuclear Information System (INIS)

Ishiguro, Misako

2002-01-01

Lattice gas automaton (LGA) models developed so far are just for Cartesian geometries, and no direct approach to rotated fluid flows is found. In this paper, LGA method is applied to model a two-dimensional rotated flow. Several problems specific to the rotated flow are to be solved: hexagonal lattice geometry to effectively identify the neighbors, boundary condition for irregular walls, multi-speed scheme to represent angular-oriented fluid velocity υ θ ≅γω, shape of macroscopic domain for statistics, formula to obtain macroscopic quantities such as density and mean fluid velocities, application method of Fermi-Dirac function to the initial particle arrangement. For this purpose, FHP-I type hexagonal lattice model is revised and a new LGA model with stochastic particle movement is proposed. The results of the trial calculation are shown. It is also investigated whether or not the underlying microscopic Boolean equations newly introduced leads to Navier-Stokes equation. (author)

Topography-guided treatment of irregular astigmatism with the wavelight excimer laser.

Science.gov (United States)

Jankov, Mirko R; Panagopoulou, Sophia I; Tsiklis, Nikolaos S; Hajitanasis, Georgos C; Aslanides, loannis M; Pallikaris, loannis G

2006-04-01

To evaluate the feasibility, safety, and predictability of correcting high irregular astigmatism in symptomatic eyes with the use of topography-guided photoablation. In a prospective, non-comparative case series, 16 consecutive symptomatic eyes of 11 patients with small hyperopic and myopic excimer laser optical zones, decentered and irregular ablation after corneal graft, and corneal scars were operated. Uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest and cycloplegic refraction, and corneal topography, with asphericity and regularity, were analyzed. LASIK (n = 10) and photorefractive keratectomy (n = 6) were performed using the ALLEGRETTO WAVE excimer laser and T-CAT software (Topography-guided Customized Ablation Treatment; WaveLight Laser Technologie AG, Erlangen, Germany). In the LASIK group, UCVA improved from 0.81 +/- 0.68 IogMAR (20/130) (range: 0.2 to 2.0) to 0.29 +/- 0.21 logMAR (20/39) (range: 0.1 to 0.7) at 6 months. In the PRK group, mean UCVA improved from 0.89 +/- 0.87 IogMAR (20/157) (range: 0.1 to 2.0) to 0.42 +/- 0.35 logMAR (20/53) (range: 0.1 to 1.0) at 6 months. Best spectacle-corrected visual acuity did not change significantly in either group. One PRK patient lost one line of BSCVA. Refractive cylinder for the LASIK group improved from -2.53 +/- 1.71 diopters (D) (range: -0.75 to -5.75 D) to -1.28 +/- 0.99 D (range: 0 to -2.50 D) at 6 months. Refractive cylinder in the PRK group improved from -2.21 +/- 2.11 D (range: -0.25 to -5.50 D) to -1.10 +/- 0.42 D (range: -0.50 to -1.50 D). Index of surface irregularity showed a decrease from 60 +/- 12 (range: 46 to 89) to 50 +/- 9 (range: 32 to 63) at 6 months in the LASIK group whereas no significant change was noted in the PRK group. Subjective symptoms, such as glare, halos, ghost images, starbursts, and monocular diplopia, were not present postoperatively. Topography-guided LASIK and PRK resulted in a significant reduction of refractive cylinder and

Rocket in situ observation of equatorial plasma irregularities in the region between E and F layers over Brazil

Directory of Open Access Journals (Sweden)

S. Savio Odriozola

2017-03-01

Full Text Available A two-stage VS-30 Orion rocket was launched from the equatorial rocket launching station in Alcântara, Brazil, on 8 December 2012 soon after sunset (19:00 LT, carrying a Langmuir probe operating alternately in swept and constant bias modes. At the time of launch, ground equipment operated at equatorial stations showed rapid rise in the base of the F layer, indicating the pre-reversal enhancement of the F region vertical drift and creating ionospheric conditions favorable for the generation of plasma bubbles. Vertical profiles of electron density estimated from Langmuir probe data showed wave patterns and small- and medium-scale plasma irregularities in the valley region (100–300 km during the rocket upleg and downleg. These irregularities resemble those detected by the very high frequency (VHF radar installed at Jicamarca and so-called equatorial quasi-periodic echoes. We present evidence suggesting that these observations could be the first detection of this type of irregularity made by instruments onboard a rocket.

Population Structure of Pythium irregulare, P. ultimum, and P. sylvaticum in Forest Nursery Soils of Oregon and Washington.

Science.gov (United States)

Weiland, Jerry E; Garrido, Patricia; Kamvar, Zhian N; Espíndola, Andrés S; Marek, Stephen M; Grünwald, Niklaus J; Garzón, Carla D

2015-05-01

Pythium species are important soilborne pathogens occurring in the forest nursery industry of the Pacific Northwest. However, little is known about their genetic diversity or population structure and it is suspected that isolates are moved among forest nurseries on seedling stock and shared field equipment. In order to address these concerns, a total of 115 isolates of three Pythium species (P. irregulare, P. sylvaticum, and P. ultimum) were examined at three forest nurseries using simple sequence repeat (SSR) and amplified fragment length polymorphism (AFLP) markers. Analyses revealed distinct patterns of intraspecific variation for the three species. P. sylvaticum exhibited the most diversity, followed by P. irregulare, while substantial clonality was found in P. ultimum. For both P. irregulare and P. sylvaticum, but not P. ultimum, there was evidence for significant variation among nurseries. However, all three species also exhibited at least two distinct lineages not associated with the nursery of origin. Finally, evidence was found that certain lineages and clonal genotypes, including fungicide-resistant isolates, are shared among nurseries, indicating that pathogen movement has occurred.

Evaluation of head movement periodicity and irregularity during locomotion of Caenorhabditis elegans

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Ryuzo eShingai

2013-03-01

Full Text Available Caenorhabditis elegans is suitable for studying the nervous system, which controls behavior. C. elegans shows sinusoidal locomotion on an agar plate. The head moves not only sinusoidally but also more complexly, which reflects regulation of the head muscles by the nervous system. The head movement becomes more irregular with senescence. To date, the head movement complexity has not been quantitatively analyzed. We propose two simple methods for evaluation of the head movement regularity on an agar plate using image analysis. The methods calculate metrics that are a measure of how the head end movement is correlated with body movement. In the first method, the length along the trace of the head end on the agar plate between adjacent intersecting points of the head trace and the quasi-midline of the head trace, which was made by sliding an averaging window of 1/2 the body wavelength, was obtained. Histograms of the lengths showed periodic movement of the head and deviation from it. In the second method, the intersections between the trace of the head end and the trace of the 5 (near the pharynx or 50% (the mid-body point from the head end in the centerline length of the worm image were marked. The length of the head trace between adjacent intersections was measured, and a histogram of the lengths was produced. The histogram for the 5% point showed deviation of the head end movement from the movement near the pharynx. The histogram for the 50% point showed deviation of the head movement from the sinusoidal movement of the body center. Application of these methods to wild type and several mutant strains enabled evaluation of their head movement periodicity and irregularity, and revealed a difference in the age-dependence of head movement irregularity between the strains. A set of five parameters obtained from the histograms reliably identifies differences in head movement between strains.

New advantages of the combined GPS and GLONASS observations for high-latitude ionospheric irregularities monitoring: case study of June 2015 geomagnetic storm

Science.gov (United States)

Cherniak, Iurii; Zakharenkova, Irina

2017-05-01

Monitoring, tracking and nowcasting of the ionospheric plasma density disturbances using dual-frequency measurements of the Global Positioning System (GPS) signals are effectively carried out during several decades. Recent rapid growth and modernization of the ground-based segment gives an opportunity to establish a great database consisting of more than 6000 stations worldwide which provide GPS signals measurements with an open access. Apart of the GPS signals, at least two-third of these stations receive simultaneously signals transmitted by another Global Navigation Satellite System (GNSS)—the Russian system GLONASS. Today, GLONASS signal measurements are mainly used in navigation and geodesy only and very rarely for ionosphere research. We present the first results demonstrating advantages of using several independent but compatible GNSS systems like GPS and GLONASS for improvement of the permanent monitoring of the high-latitude ionospheric irregularities. For the first time, the high-resolution two-dimensional maps of ROTI perturbation were made using not only GPS but also GLONASS measurements. We extend the use of the ROTI maps for analyzing ionospheric irregularities distribution. We demonstrate that the meridional slices of the ROTI maps can be effectively used to study the occurrence and temporal evolution of the ionospheric irregularities. The meridional slices of the geographical sectors with a high density of the GPS and GLONASS measurements can represent spatio-temporal dynamics of the intense ionospheric plasma density irregularities with very high resolution, and they can be effectively used for detailed study of the space weather drivers on the processes of the ionospheric irregularities generation, development and their lifetimes. Using a representative database of 5800 ground-based GNSS stations located worldwide, we have investigated the occurrence of the high-latitude ionospheric plasma density irregularities during the geomagnetic storm of

Irregular meal pattern-effects on energy expenditure, metabolism and appetite regulation: a randomized controlled trial in healthy normal-weight women

OpenAIRE

Alhussain, Maha H; Macdonald, Ian A.; Taylor, Moira A.

2016-01-01

Background: Obesity is increasing in parallel with greater all-day food availability. The latter may promote meal irregularity, dysregulation of the energy balance, and poor metabolic health.\\ud Objective: We investigated the effect of meal irregularity on the thermic effect of food (TEF), lipid concentrations, carbohydrate metabolism, subjective appetite, and gut hormones in healthy women.\\ud Design: Eleven normal-weight women (18–40 y of age) were recruited in a randomized crossover trial w...

Validity of autorefractor based screening method for irregular astigmatism compared to the corneal topography- a cross sectional study

Directory of Open Access Journals (Sweden)

Alicia Galindo-Ferreiro

2017-09-01

Full Text Available AIM: To present a method of screening for irregular astigmatism with an autorefractor and its determinants compared to corneal topography. METHODS: This cross-sectional validity study was conducted in 2013 at an eye hospital in Spain. A tabletop autorefractor (test 1 was used to measure the refractive status of the anterior surface of the cornea at two corneal meridians of each eye. Then corneal topography (test 2 and Bogan’s classification was used to group eyes into those with regular or no astigmatism (GRI and irregular astigmatism (GRII. Test 1 provided a single absolute value for the greatest cylinder difference (Vr. The receiver operating characteristic (ROC were plotted for the Vr values measured by test 1 for GRI and GRII eyes. On the basis a Vr value of 1.25 D as cut off, sensitivity, specificity were also calculated. RESULTS: The study sample was comprised of 260 eyes (135 patients. The prevalence of irregular astigmatism was 42% [95% confidence interval (CI: 36, 48]. Based on test 2, there were 151 eyes in GRI and 109 eyes in GRII. The median Vr was 0.75 D (25% quartile, 0.5 D for GRI and 1.75 D (25% quartile, 1.25 D for GRII. The area under curve was 0.171 for GRI and 0.83 for GRII. The sensitivity of test I was 78.1% and the specificity was 76.1%. CONCLUSION: A conventional autorefractor can be effective as a first level screening method to detect irregular corneal astigmatism in places where corneal topography facilities are not available.

Overcoming trends in irregularly spaced locations by regional polish - exemplified by estimation of the range of influence between Salmonella Dublin-seropositive cattle herds

DEFF Research Database (Denmark)

Ersbøll, Annette Kjær; Ersbøll, Bjarne Kjær

2010-01-01

The aim of the study was to develop a procedure to remove spatial trends in irregularly spaced data, with trends partly due to regional differences. Median polish is often used on regularly spaced (lattice) data where column and row medians are removed. For irregularly spaced data a low-resolutio...

A Control Simulation Method of High-Speed Trains on Railway Network with Irregular Influence

International Nuclear Information System (INIS)

Yang Lixing; Li Xiang; Li Keping

2011-01-01

Based on the discrete time method, an effective movement control model is designed for a group of highspeed trains on a rail network. The purpose of the model is to investigate the specific traffic characteristics of high-speed trains under the interruption of stochastic irregular events. In the model, the high-speed rail traffic system is supposed to be equipped with the moving-block signalling system to guarantee maximum traversing capacity of the railway. To keep the safety of trains' movements, some operational strategies are proposed to control the movements of trains in the model, including traction operation, braking operation, and entering-station operation. The numerical simulations show that the designed model can well describe the movements of high-speed trains on the rail network. The research results can provide the useful information not only for investigating the propagation features of relevant delays under the irregular disturbance but also for rerouting and rescheduling trains on the rail network. (general)

CORPORATE GOVERNANCE AND ACCOUNTING IRREGULARITIES: Evidence from the Two-tiered Board Structure in Indonesia

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Jaswadi JASWADI

2012-09-01

Full Text Available This study aims to investigate the extent to which the Indonesian corporate governance mechanism acts as an effective tool for protecting financial statements users against accounting irregularities. Considering that accounting irregularities might occur in between error and the fraud act, this study reviews the literature on minimizing the seriousness of these reporting incidences. The level of seriousness in misstatements is more severe when: (1 there is absence of financial expert(s on supervisory boards and audit committees, (2 companies have short tenured-CEOs and poor internal control systems, and (3 auditors are solely appointed by firms’ BOCs without agreement of block holders (known as referral. In addition, an examination of simultaneous effects of each corporate governance dimension reveals a general weakness of the BOCs and their audit committees. However, the BOC and audit committee could be an effective tool in mitigating reporting incidences, especially when they show high-quality collaboration.

Amperometric detection of morphine based on poly(3,4-ethylenedioxythiophene) immobilized molecularly imprinted polymer particles prepared by precipitation polymerization

International Nuclear Information System (INIS)

Ho, K.-C.; Yeh, W.-M.; Tung, T.-S.; Liao, J.-Y.

2005-01-01

Molecular imprinting is a novel technique used for chiral separation, artificial antibodies, sensors, and assays. Typically, molecular imprinted polymers (MIPs) are monoliths with irregular shapes. However, microspherical shapes with more uniform size can be obtained by the method of precipitation polymerization, which offers a higher active surface area by manipulating its compositions. In this study, MIP particles for the target molecule, morphine, were synthesized using a precipitation polymerization method that is more facile than the previous one that produced a thermally polymerized bulk. The conducting polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), was utilized to immobilize the MIP particles onto the indium tin oxide (ITO) glass as a MIP/PEDOT-modified electrode. The sensitivity for the MIP/PEDOT-modified electrode with MIP particles was 41.63 μA/cm 2 mM, which is more sensitive than that with non-MIP particles or that of a single PEDOT film with no incorporated particles in detecting morphine ranging from 0.1 to 2 mM. The detection limit was 0.3 mM (S/N = 3). In addition, we presented that the modified electrode can discriminate codeine that plays an interfering species

Aluminium EN AW-2124 alloy matrix composites reinforced with Ti(C,N), BN and Al2O3 particles

International Nuclear Information System (INIS)

Dobrzanski, L.A.; Wlodarczyk, A.; Adamiak, M.

2003-01-01

Investigation results of the aluminium alloy EN AW-2124 matrix composite materials with particles of the powders Ti(C,N), BN and Al 2 O 3 (15 wt.%) are presented in the paper. In order to obtain uniform distribution of reinforcement particles in aluminium alloy matrix powders of composite components have been milled in the rotary ball-bearing pulverizer. The composites have been pressed in laboratory vertical press at room temperature under the pressure of 500 kN. Obtained die samplings have been heated to the temperature 520-550 o C and extruded. Bars of diameter 8 mm have been received as a final product. Metallographic examination of the composites materials' structure shows non-uniform distribution of reinforced powders in the aluminium alloy matrix banding of reinforcements particles corresponds to the extrusion direction. Particles of reinforcement distribution in aluminium alloy matrix is irregular, some agglomerations of powder of aluminium oxide and porosity of different size have been noticed. Investigations of hardness and ultimate compressive strength show that the particles of reinforcement improve mechanical properties of composite materials. Investigations of compressive strength, carried out at room temperature, enable to compare mechanical properties of matrix and composite. (author)

Menstrual irregularities and lactation failure may precede thyroid dysfunction or goitre.

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Joshi J

1993-07-01

Full Text Available Menstrual and reproductive history of 178 women referred to the thyroid clinic was compared with 49 healthy controls. Cases were classified as euthyroid, hypothyroid or hyperthyroid after clinical examination and after serum T3, T4, TSH measurements. Reproductive history was related chronologically to symptoms and signs of thyroid dysfunction. Only 31.8% of hypothyroid and 35.3% of hyperthyroid women had normal menstrual pattern in contrast with 56.3% of Euthyroid and 87.8% of healthy controls (p < 0.001. Reproductive failure (infertility, pregnancy wastage, failure of lactation occurred in 37.5% of hypothyroid and 36.5% of hyperthyroid cases against 16.3% of euthyroid and 16.7% of healthy controls (p < 0.05. Interestingly, in 45% of cases with menstrual abnormality, the anomaly was antecedent to other clinical features by a variable period of two months to ten years. Reproductive failure and lactation failure also preceded thyroid dysfunction or goitre. Reproductive dysfunction may therefore be considered as one of the presenting symptoms of thyroid disorders in women, keeping in mind both menstrual irregularities and lactation failure may also arise from other common or idiopathic origins. Especially in women with menstrual irregularities in the perimenopausal age if thyroid dysfunction is detected, pharmacotherapy may be a superior alternative to surgical interventions like hysterectomy.

Helical wire stress analysis of unbonded flexible riser under irregular response

Science.gov (United States)

Wang, Kunpeng; Ji, Chunyan

2017-06-01

A helical wire is a critical component of an unbonded flexible riser prone to fatigue failure. The helical wire has been the focus of much research work in recent years because of the complex multilayer construction of the flexible riser. The present study establishes an analytical model for the axisymmetric and bending analyses of an unbonded flexible riser. The interlayer contact under axisymmetric loads in this model is modeled by setting radial dummy springs between adjacent layers. The contact pressure is constant during the bending response and applied to determine the slipping friction force per unit helical wire. The model tracks the axial stress around the angular position at each time step to calculate the axial force gradient, then compares the axial force gradient with the slipping friction force to judge the helical wire slipping region, which would be applied to determine the bending stiffness for the next time step. The proposed model is verified against the experimental data in the literature. The bending moment-curvature relationship under irregular response is also qualitatively discussed. The stress at the critical point of the helical wire is investigated based on the model by considering the local flexure. The results indicate that the present model can well simulate the bending stiffness variation during irregular response, which has significant effect on the stress of helical wire.

Stability Analysis Method for Rock Slope with an Irregular Shear Plane Based on Interface Model

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Changqing Qi

2018-01-01

Full Text Available Landslide developed in rock mass usually has irregular shear plane. An approach for calculating distributed factor of safety of the irregular shear plane was put forward in this paper. The presented method can obtain not only the detailed stability status at any grid node of a complex shear plane but also the global safety of the slope. Thus, it is helpful to thoroughly understand the mechanism of slope failure. Comparing with the result obtained through the limit equilibrium method, the presented method was proved to be more accurate and suitable for stability analysis of rock slope with a thin shear plane. The stability of a potentially unstable rock slope was analyzed based on the presented method at the end of this paper. The detailed local stability, global stability, and the potential failure mechanism were provided.

Optical properties, morphology and elemental composition of atmospheric particles at T1 supersite on MILAGRO campaign

Science.gov (United States)

Carabali, G.; Mamani-Paco, R.; Castro, T.; Peralta, O.; Herrera, E.; Trujillo, B.

2012-03-01

Atmospheric particles were sampled at T1 supersite during MILAGRO campaign, in March 2006. T1 was located at the north of Mexico City (MC). Aerosol sampling was done by placing copper grids for Transmission Electron Microscope (TEM) on the last five of an 8-stage MOUDI cascade impactor. Samples were obtained at different periods to observe possible variations on morphology. Absorption and scattering coefficients, as well as particle concentrations (0.01-3 μm aerodynamic diameter) were measured simultaneously using a PSAP absorption photometer, a portable integrating nephelometer, and a CPC particle counter. Particle images were acquired at different magnifications using a CM 200 Phillips TEM-EDAX system, and then calculated the border-based fractal dimension. Also, Energy Dispersive X-Ray Spectroscopy (EDS) was used to determine the elemental composition of particles. The morphology of atmospheric particles for two aerodynamic diameters (0.18 and 1.8 μm) was compared using border-based fractal dimension to relate it to the other particle properties, because T1-generated particles have optical, morphological and chemical properties different from those transported by the MC plume. Particles sampled under MC pollution influence showed not much variability, suggesting that more spherical particles (border-based fractal dimension close to 1.0) are more common in larger sizes (d50 = 1.8 μm), which may be attributed to aerosol aging and secondary aerosol formation. Between 06:00 and 09:00 a.m., smaller particles (d50 = 0.18 μm) had more irregular shapes resulting in higher border-based fractal dimensions (1.2-1.3) for samples with more local influence. EDS analysis in d50 = 0.18 μm particles showed high contents of carbonaceous material, Si, Fe, K, and Co. Perhaps, this indicates an impact from industrial and vehicle emissions on atmospheric particles at T1.

Application of digital tomosynthesis in diagnosing the fractures or dislocations in irregular bones and regions with complex structures.

Science.gov (United States)

Tuerdi, Batuer; Wang, Hui; Zhang, Ying; Zhou, Hao; Zhang, Hao

2015-01-01

The application potential of digital tomosynthesis in diagnosing fractures or dislocations in irregular bones and regions with complex structures was evaluated. Digital radiography and tomosynthesis were performed in 121 patients, and the image quality, accuracy, sensitivity, and specificity were compared. The number of participants with a definite diagnosis of fracture and/or dislocation was 98. The ratio of excellent images, accuracy, sensitivity, and specificity of digital tomosynthesis were higher than that of direct radiography. Digital tomosynthesis could be applied in the diagnosis of fractures or dislocations in irregular bones and regions with complex structures. Copyright © 2015 Elsevier Inc. All rights reserved.

Irregular Homogeneity Domains in Ternary Intermetallic Systems

Directory of Open Access Journals (Sweden)

Jean-Marc Joubert

2015-12-01

Full Text Available Ternary intermetallic A–B–C systems sometimes have unexpected behaviors. The present paper examines situations in which there is a tendency to simultaneously form the compounds ABx, ACx and BCx with the same crystal structure. This causes irregular shapes of the phase homogeneity domains and, from a structural point of view, a complete reversal of site occupancies for the B atom when crossing the homogeneity domain. This work reviews previous studies done in the systems Fe–Nb–Zr, Hf–Mo–Re, Hf–Re–W, Mo–Re–Zr, Re–W–Zr, Cr–Mn–Si, Cr–Mo–Re, and Mo–Ni–Re, and involving the topologically close-packed Laves, χ and σ phases. These systems have been studied using ternary isothermal section determination, DFT calculations, site occupancy measurement using joint X-ray, and neutron diffraction Rietveld refinement. Conclusions are drawn concerning this phenomenon. The paper also reports new experimental or calculated data on Co–Cr–Re and Fe–Nb–Zr systems.

Photographic investigation into the mechanism of combustion in irregular detonation waves

Science.gov (United States)

Kiyanda, C. B.; Higgins, A. J.

2013-03-01

Irregular detonations are supersonic combustion waves in which the inherent multi-dimensional structure is highly variable. In such waves, it is questionable whether auto-ignition induced by shock compression is the only combustion mechanism present. Through the use of high-speed schlieren and self-emitted light photography, the velocity of the different components of detonation waves in a {{ CH}}_4+2{ O}_2 mixture is analyzed. The observed burn-out of unreacted pockets is hypothesized to be due to turbulent combustion.

Tamoxifen treatment of bleeding irregularities associated with Norplant use.

Science.gov (United States)

Abdel-Aleem, Hany; Shaaban, Omar M; Amin, Ahmed F; Abdel-Aleem, Aly M

2005-12-01

To evaluate the possible role of tamoxifen (selective estrogen receptor modulators, SERM) in treating bleeding irregularities associated with Norplant contraceptive use. Randomized clinical trial including 100 Norplant users complaining of vaginal bleeding irregularities. The trial was conducted in the Family Planning Clinic of Assiut University Hospital. Women were assigned at random to receive tamoxifen tablets (10 mg) twice daily for 10 days or similar placebo. Women were followed-up for 3 months. The end points were percentage of women who stopped bleeding during treatment, bleeding/spotting days during the period of follow-up, effect of treatment on their lifestyle, and side effects and discontinuation of contraception. There was good compliance with treatment. At the end of treatment, a significantly higher percentage of tamoxifen users stopped bleeding in comparison to the control group (88% vs. 68%, respectively; p=.016). Women who used tamoxifen had significantly less bleeding and/or spotting days than women who used placebo, during the first and second months. During the third month, there were no significant differences between the two groups. Women who used tamoxifen reported improvement in performing household activities, religious duties and in sexual life, during the first 2 months. In the third month, there were no differences between the two groups. There were no significant differences between tamoxifen and placebo groups in reporting side effects. In the group who used tamoxifen, two women discontinued Norplant use because of bleeding vs. nine women in the placebo group. Tamoxifen use at a dose of 10 mg twice daily orally, for 10 days, has a beneficial effect on vaginal bleeding associated with Norplant use. In addition, the bleeding pattern was better in women who used tamoxifen for the following 2 months after treatment. However, these results have to be confirmed in a larger trial before advocating this line of treatment.

Report on the HAARP 2008 Winter Campaign Focusing on Artificial Ionospheric Irregularities

Science.gov (United States)

2008-07-31

Figure Bl. Magnetic field variations recorded by the fluxgate magnetometer 30 Figure B2. Composite ionogram showing the variation of the reflection...variation was monitored by the Fluxgate Magnetometer . The density irregularities were monitored by the Ionosonde. 20:00 Preliminary Results The...magnetic field variations in three directions (H, D, and Z) recorded by the fluxgate magnetometer from UTC 20:00 to 04:00 are shown in the plots of

Using Localised Quadratic Functions on an Irregular Grid for Pricing High-Dimensional American Options

NARCIS (Netherlands)

Berridge, S.J.; Schumacher, J.M.

2004-01-01

We propose a method for pricing high-dimensional American options on an irregular grid; the method involves using quadratic functions to approximate the local effect of the Black-Scholes operator.Once such an approximation is known, one can solve the pricing problem by time stepping in an explicit

Mental health care for irregular migrants in Europe: Barriers and how they are overcome

NARCIS (Netherlands)

Straßmayr, Christa; Matanov, Aleksandra; Priebe, Stefan; Barros, Henrique; Canavan, Reamonn; Díaz-Olalla, José Manuel; Gabor, Edina; Gaddini, Andrea; Greacen, Tim; Holcnerová, Petra; Kluge, Ulrike; Welbel, Marta; Nicaise, Pablo; Schene, Aart H.; Soares, Joaquim J. F.; Katschnig, Heinz

2012-01-01

Background: Irregular migrants (IMs) are exposed to a wide range of risk factors for developing mental health problems. However, little is known about whether and how they receive mental health care across European countries. The aims of this study were (1) to identify barriers to mental health care

Variations in tumor size and position due to irregular breathing in 4D-CT: A simulation study

International Nuclear Information System (INIS)

Sarker, Joyatee; Chu, Alan; Mui, Kit; Wolfgang, John A.; Hirsch, Ariel E.; Chen, George T. Y.; Sharp, Gregory C.

2010-01-01

Purpose: To estimate the position and volume errors in 4D-CT caused by irregular breathing. Methods: A virtual 4D-CT scanner was designed to reproduce axial mode scans with retrospective resorting. This virtual scanner creates an artificial spherical tumor based on the specifications of the user, and recreates images that might be produced by a 4D-CT scanner using a patient breathing waveform. 155 respiratory waveforms of patients were used to test the variability of 4D-CT scans. Each breathing waveform was normalized and scaled to 1, 2, and 3 cm peak-to-peak motion, and artificial tumors with 2 and 4 cm radius were simulated for each scaled waveform. The center of mass and volume of resorted 4D-CT images were calculated and compared to the expected values of center of mass and volume for the artificial tumor. Intrasubject variability was investigated by running the virtual scanner over different subintervals of each patient's breathing waveform. Results: The average error in the center of mass location of an artificial tumor was less than 2 mm standard deviation for 2 cm motion. The corresponding average error in volume was less than 4%. In the worst-case scenarios, a center of mass error of 1.0 cm standard deviation and volume errors of 30%-60% at inhale were found. Systematic errors were observed in a subset of patients due to irregular breathing, and these errors were more pronounced when the tumor volume is smaller. Conclusions: Irregular breathing during 4D-CT simulation causes systematic errors in volume and center of mass measurements. These errors are small but depend on the tumor size, motion amplitude, and degree of breathing irregularity.

Manufacturing of Cast Metal Foams with Irregular Cell Structure

Directory of Open Access Journals (Sweden)

Kroupová I.

2015-06-01

Full Text Available Metallic foams are materials of which the research is still on-going, with the broad applicability in many different areas (e.g. automotive industry, building industry, medicine, etc.. These metallic materials have specific properties, such as large rigidity at low density, high thermal conductivity, capability to absorb energy, etc. The work is focused on the preparation of these materials using conventional casting technology (infiltration method, which ensures rapid and economically feasible method for production of shaped components. In the experimental part we studied conditions of casting of metallic foams with open pores and irregular cell structure made of ferrous and nonferrous alloys by use of various types of filler material (precursors.

Investigating the size, shape and surface roughness dependence of polarization lidars with light-scattering computations on real mineral dust particles: Application to dust particles' external mixtures and dust mass concentration retrievals

Science.gov (United States)

Mehri, Tahar; Kemppinen, Osku; David, Grégory; Lindqvist, Hannakaisa; Tyynelä, Jani; Nousiainen, Timo; Rairoux, Patrick; Miffre, Alain

2018-05-01

Our understanding of the contribution of mineral dust to the Earth's radiative budget is limited by the complexity of these particles, which present a wide range of sizes, are highly-irregularly shaped, and are present in the atmosphere in the form of particle mixtures. To address the spatial distribution of mineral dust and atmospheric dust mass concentrations, polarization lidars are nowadays frequently used, with partitioning algorithms allowing to discern the contribution of mineral dust in two or three-component particle external mixtures. In this paper, we investigate the dependence of the retrieved dust backscattering (βd) vertical profiles with the dust particle size and shape. For that, new light-scattering numerical simulations are performed on real atmospheric mineral dust particles, having determined mineralogy (CAL, DOL, AGG, SIL), derived from stereogrammetry (stereo-particles), with potential surface roughness, which are compared to the widely-used spheroidal mathematical shape model. For each dust shape model (smooth stereo-particles, rough stereo-particles, spheroids), the dust depolarization, backscattering Ångström exponent, lidar ratio are computed for two size distributions representative of mineral dust after long-range transport. As an output, two Saharan dust outbreaks involving mineral dust in two, then three-component particle mixtures are studied with Lyon (France) UV-VIS polarization lidar. If the dust size matters most, under certain circumstances, βd can vary by approximately 67% when real dust stereo-particles are used instead of spheroids, corresponding to variations in the dust backscattering coefficient as large as 2 Mm- 1·sr- 1. Moreover, the influence of surface roughness in polarization lidar retrievals is for the first time discussed. Finally, dust mass-extinction conversion factors (ηd) are evaluated for each assigned shape model and dust mass concentrations are retrieved from polarization lidar measurements. From

Thyroid function and body weight in girls with irregular menstrual cycle living in mild iodine deficiency region

Directory of Open Access Journals (Sweden)

L Sh Vagapova

2011-09-01

Full Text Available To establish the relation of body weight indexes and functional state of thyroid in female adolescents with menstrual cycle disorder, living in the iodine-deficiency region, the investigation was conducted in 130 female adolescents with irregular menses. Obesity incidence and overweight in them was 18.5%, body weight deficiency was 43.8%.37.7% of the girls had normal body weight. Statistically significant differences were not defined according to TSH, fT4 and fT3 in patients with different body weight indexes. So, the results of investigation can help to come to the conclusion about the absence of true correlation between body weight and functional thyroid state in female adolescents with irregular menses.

Ionospheric wave and irregularity measurements using passive radio astronomy techniques

International Nuclear Information System (INIS)

Erickson, W.C.; Mahoney, M.J.; Jacobson, A.R.; Knowles, S.H.

1988-01-01

The observation of midlatitude structures using passive radio astronomy techniques is discussed, with particular attention being given to the low-frequency radio telescope at the Clark Lake Radio Observatory. The present telescope operates in the 10-125-MHz frequency range. Observations of the ionosphere at separations of a few kilometers to a few hundreds of kilometers by the lines of sight to sources are possible, allowing the determination of the amplitude, wavelength, direction of propagation, and propagation speed of ionospheric waves. Data are considered on large-scale ionospheric gradients and the two-dimensional shapes and sizes of ionospheric irregularities. 10 references

Metaphyseal cortical irregularities in children: A new perspective on a multi-focal growth variant

International Nuclear Information System (INIS)

Keats, T.E.; Joyce, J.M.

1984-01-01

The occurrence of metaphyseal cortical irregularities in adolescents in many different bones indicates a commonality of these lesions as a variation of normal growth, rater than a stress or avulsive by-product. The histologically recognized incomplete nature of the metaphysical cortex in children offers an attractive explanation for this phenomenon. (orig.)

Metaphyseal cortical irregularities in children: A new perspective on a multi-focal growth variant

Energy Technology Data Exchange (ETDEWEB)

Keats, T.E.; Joyce, J.M.

1984-07-01

The occurrence of metaphyseal cortical irregularities in adolescents in many different bones indicates a commonality of these lesions as a variation of normal growth, rather than a stress or avulsive by-product. The histologically recognized incomplete nature of the metaphysical cortex in children offers an attractive explanation for this phenomenon.

Elastic tripping analysis of corroded stiffeners in stiffened plate with irregular surfaces

Energy Technology Data Exchange (ETDEWEB)

Rahbarranji, Ahmad [AmirKabir University of Technology, Tehran (Iran, Islamic Republic of)

2014-09-15

Tripping of stiffeners is one of the buckling modes of stiffened panels which could rapidly lead to its catastrophic failure. Loss of thickness in the web and flange of stiffeners due to corrosion reduces elastic buckling strength. It is common practice to assume a uniform thickness reduction for corroded surfaces. To estimate the remaining strength of a corroded structure, a much higher level of accuracy is required since corroded surfaces are irregular. Finite element method is employed to analyze elastic tripping stress of corroded stiffeners with irregular surfaces. Comparing the results with elastic tripping stress of un-corroded stiffener, a reduction factor is introduced. It is found that for flat-bars and angle-bars the reduction factor increases by increasing corrosion loss; however, for tee-bars remains almost unchanged. Surface roughness has no significant effect on reduction of tripping Euler stress of angle-bars and flat-bars; however, it has an effect on reduction of tripping Euler stress of small flat-bars. For high values of corrosion loss, reduction of tripping Euler stress is higher in flat-bars than angle-bars. Corrosion at the mid-length or ends of flat-bars is more detrimental than full length. Corrosion at the ends of angle-bars is more detrimental than full length and mid-length.

Nonfeed application of rendered animal proteins for microbial production of eicosapentaenoic acid by the fungus Pythium irregulare.

Science.gov (United States)

Liang, Yi; Garcia, Rafael A; Piazza, George J; Wen, Zhiyou

2011-11-23

Rendered animal proteins are well suited for animal nutrition applications, but the market is maturing, and there is a need to develop new uses for these products. The objective of this study is to explore the possibility of using animal proteins as a nutrient source for microbial production of omega-3 polyunsaturated fatty acids by the microalga Schizochytrium limacinum and the fungus Pythium irregulare. To be absorbed by the microorganisms, the proteins needed to be hydrolyzed into small peptides and free amino acids. The utility of the protein hydrolysates for microorganisms depended on the hydrolysis method used and the type of microorganism. The enzymatic hydrolysates supported better cell growth performance than the alkali hydrolysates did. P. irregulare displayed better overall growth performance on the experimental hydrolysates compared to S. limacinum. When P. irregulare was grown in medium containing 10 g/L enzymatic hydrolysate derived from meat and bone meal or feather meal, the performance of cell growth, lipid synthesis, and omega-3 fatty acid production was comparable to the that of culture using commercial yeast extract. The fungal biomass derived from the animal proteins had 26-29% lipid, 32-34% protein, 34-39% carbohydrate, and industrial microorganisms which can produce omega-3 fatty acids for making omega-3-fortified foods or feeds.

Strain-rate effect on initial crush stress of irregular honeycomb under dynamic loading and its deformation mechanism

Science.gov (United States)

Wang, Peng; Zheng, Zhijun; Liao, Shenfei; Yu, Jilin

2018-02-01

The seemingly contradictory understandings of the initial crush stress of cellular materials under dynamic loadings exist in the literature, and a comprehensive analysis of this issue is carried out with using direct information of local stress and strain. Local stress/strain calculation methods are applied to determine the initial crush stresses and the strain rates at initial crush from a cell-based finite element model of irregular honeycomb under dynamic loadings. The initial crush stress under constant-velocity compression is identical to the quasi-static one, but less than the one under direct impact, i.e. the initial crush stresses under different dynamic loadings could be very different even though there is no strain-rate effect of matrix material. A power-law relation between the initial crush stress and the strain rate is explored to describe the strain-rate effect on the initial crush stress of irregular honeycomb when the local strain rate exceeds a critical value, below which there is no strain-rate effect of irregular honeycomb. Deformation mechanisms of the initial crush behavior under dynamic loadings are also explored. The deformation modes of the initial crush region in the front of plastic compaction wave are different under different dynamic loadings.

Modalities of Tonometry and their Accuracy with Respect to Corneal Thickness and Irregularities

Directory of Open Access Journals (Sweden)

Carlos Gustavo V. De Moraes

2008-01-01

Each of the many different commercially available tonometers has specific advantages and disadvantages. New non-invasive technologies are getting closer to a precise estimation of the true IOP. However, among all tonometers, none is highly accurate when both corneal thickness and surface irregularities are present. Fifty years after its development, Goldmann tonometry remains the gold standard to which all other devices are compared.

Serbian migration policy concerning irregular migration and asylum in the context of the EU integration process

Directory of Open Access Journals (Sweden)

Marta Stojić-Mitrović

2016-02-01

Full Text Available In this paper I would like to present Serbian migration policy concerning irregular migration and asylum in the context of the attempts of the Serbian state to become a member of the European Union. I would describe the history of the asylum system prior and after the implementation of the independent asylum system in Serbia in 2008. My presentation of the Serbian migration policy would be channelled by the analysis of some particular political issues, such as the externalization of the EU borders’ control, as well as some relevant elements of the European integration process, like visa liberalization. The second, more culturally specific dimension of the issue would be accessed through the demonstration of both legislative and public conceptualizations of the irregular migrants, asylum seekers and refugees in Serbia.

Fabrication of ITO particles using a combination of a homogeneous precipitation method and a seeding technique and their electrical conductivity

Directory of Open Access Journals (Sweden)

Yoshio Kobayashi

2015-09-01

Full Text Available The present work proposes a method to fabricate indium tin oxide (ITO particles using precursor particles synthesized with a combination of a homogeneous precipitation method and a seeding technique, and it also describes their electronic conductivity properties. Seed nanoparticles were produced using a co-precipitation method with aqueous solutions of indium (III chloride, tin (IV chloride aqueous solution and sodium hydroxide. Three types of ITO nanoparticles were fabricated. The first type was fabricated using the co-precipitation method (c-ITO. The second and third types were fabricated using a homogeneous precipitation method with the seed nanoparticles (s-ITO and without seeds (n-ITO. The as-prepared precursor particles were annealed in air at 500 °C, and their crystal structures were cubic ITO. The c-ITO nanoparticles formed irregular-shaped agglomerates of nanoparticles. The n-ITO nanoparticles had a rectangular-parallelepiped or quasi-cubic structure. Most s-ITO nanoparticles had a quasi-cubic structure, and their size was larger than the n-ITO particles. The volume resistivities of the c-ITO, n-ITO and s-ITO powders decreased in that order because the regular-shaped particles were made to strongly contact with each other.

The phase curve survey of the irregular saturnian satellites: A possible method of physical classification

Science.gov (United States)

Bauer, James M.; Grav, Tommy; Buratti, Bonnie J.; Hicks, Michael D.

2006-09-01

During its 2005 January opposition, the saturnian system could be viewed at an unusually low phase angle. We surveyed a subset of Saturn's irregular satellites to obtain their true opposition magnitudes, or nearly so, down to phase angle values of 0.01°. Combining our data taken at the Palomar 200-inch and Cerro Tololo Inter-American Observatory's 4-m Blanco telescope with those in the literature, we present the first phase curves for nearly half the irregular satellites originally reported by Gladman et al. [2001. Nature 412, 163-166], including Paaliaq (SXX), Siarnaq (SXXIX), Tarvos (SXXI), Ijiraq (SXXII), Albiorix (SXVI), and additionally Phoebe's narrowest angle brightness measured to date. We find centaur-like steepness in the phase curves or opposition surges in most cases with the notable exception of three, Albiorix and Tarvos, which are suspected to be of similar origin based on dynamical arguments, and Siarnaq.

Soft X-ray scanning transmission X-ray microscopy (STXM) of actinide particles.

Science.gov (United States)

Nilsson, Hans J; Tyliszczak, Tolek; Wilson, Richard E; Werme, Lars; Shuh, David K

2005-09-01

A descriptive account is given of our most recent research on the actinide dioxides with the Advanced Light Source Molecular Environmental Science (ALS-MES) Beamline 11.0.2 soft X-ray scanning transmission X-ray microscope (STXM) at the Lawrence Berkeley National Laboratory (LBNL). The ALS-MES STXM permits near-edge X-ray absorption fine structure (NEXAFS) and imaging with 30-nm spatial resolution. The first STXM spectromicroscopy NEXAFS spectra at the actinide 4d5/2 edges of the imaged transuranic particles, NpO2 and PuO2, have been obtained. Radiation damage induced by the STXM was observed in the investigation of a mixed oxidation state particle (Np(V,VI)) and was minimized during collection of the actual spectra at the 4d5/2 edge of the Np(V,VI) solid. A plutonium elemental map was obtained from an irregular PuO2 particle with the dimensions of 650 x 650 nm. The Pu 4d5/2 NEXAFS spectra were collected at several different locations from the PuO2 particle and were identical. A representative oxygen K-edge spectrum from UO2 was collected and resembles the oxygen K-edge from the bulk material. The unique and current performance of the ALS-MES STXM at extremely low energies (ca. 100 eV) that may permit the successful measurement of the actinide 5d edge is documented. Finally, the potential of STXM as a tool for actinide investigations is briefly discussed.

Chitosan-coated doxorubicin nano-particles drug delivery system inhibits cell growth of liver cancer via p53/PRC1 pathway.

Science.gov (United States)

Ye, Bai-Liang; Zheng, Ru; Ruan, Xiao-Jiao; Zheng, Zhi-Hai; Cai, Hua-Jie

2018-01-01

Nano-particles have been widely used in target-specific drug delivery system and showed advantages in cancers treatment. This study aims to evaluate the effect of chitosan coated doxorubicin nano-particles drug delivery system in liver cancer. The chitosan nano-particles were prepared by using the ionic gelation method. The characterizations of the nano-particles were determined by transmission electron microscopy. The cytotoxicity was detected by MTT assay, and the endocytosis, cell apoptosis and cell cycle were examined by flow cytometry. The protein level was analyzed with western blot. The dual luciferase reporter assay was performed to assess the interaction between p53 and the promoter of PRC1, and chromatin immune-precipitation was used to verify the binding between them. The FA-CS-DOX nano-particles were irregular and spherical particles around 30-40 nm, with uniform size and no adhesion. No significant difference was noted in doxorubicin release rate between CS-DOX and FA-CS-DOX. FA-CS-DOX nano-particles showed stronger cytotoxicity than CS-DOX. FA-CS-DOX nano-particles promoted the apoptosis and arrested cell cycle at G2/M phase, and they up-regulated p53. FA-CS-DOX nano-particles inhibited cell survival through p53/PRC1 pathway. Chitosan-coated doxorubicin nano-particles drug delivery system inhibits cell growth of liver cancer by promoting apoptosis and arresting cell cycle at G2/M phase through p53/PRC1 pathway. Copyright © 2017 Elsevier Inc. All rights reserved.

Finite Length Analysis of Irregular Repetition Slotted ALOHA in the Waterfall Region

OpenAIRE

Amat, Alexandre Graell i; Liva, Gianluigi

2018-01-01

A finite length analysis is introduced for irregular repetition slotted ALOHA (IRSA) that enables to accurately estimate its performance in the moderate-to-high packet loss probability regime, i.e., in the so-called waterfall region. The analysis is tailored to the collision channel model, which enables mapping the description of the successive interference cancellation process onto the iterative erasure decoding of low-density parity-check codes. The analysis provides accurate estimates of t...

Development of Computer Program for Analysis of Irregular Non Homogenous Radiation Shielding

International Nuclear Information System (INIS)

Bang Rozali; Nina Kusumah; Hendro Tjahjono; Darlis

2003-01-01

A computer program for radiation shielding analysis has been developed to obtain radiation attenuation calculation in non-homogenous radiation shielding and irregular geometry. By determining radiation source strength, geometrical shape of radiation source, location, dimension and geometrical shape of radiation shielding, radiation level of a point at certain position from radiation source can be calculated. By using a computer program, calculation result of radiation distribution analysis can be obtained for some analytical points simultaneously. (author)

Multidimensional assessment of strongly irregular voices such as in substitution voicing and spasmodic dysphonia: a compilation of own research.

Science.gov (United States)

Moerman, Mieke; Martens, Jean-Pierre; Dejonckere, Philippe

2015-04-01

This article is a compilation of own research performed during the European COoperation in Science and Technology (COST) action 2103: 'Advance Voice Function Assessment', an initiative of voice and speech processing teams consisting of physicists, engineers, and clinicians. This manuscript concerns analyzing largely irregular voicing types, namely substitution voicing (SV) and adductor spasmodic dysphonia (AdSD). A specific perceptual rating scale (IINFVo) was developed, and the Auditory Model Based Pitch Extractor (AMPEX), a piece of software that automatically analyses running speech and generates pitch values in background noise, was applied. The IINFVo perceptual rating scale has been shown to be useful in evaluating SV. The analysis of strongly irregular voices stimulated a modification of the European Laryngological Society's assessment protocol which was originally designed for the common types of (less severe) dysphonia. Acoustic analysis with AMPEX demonstrates that the most informative features are, for SV, the voicing-related acoustic features and, for AdSD, the perturbation measures. Poor correlations between self-assessment and acoustic and perceptual dimensions in the assessment of highly irregular voices argue for a multidimensional approach.

Global scale ionospheric irregularities associated with thunderstorm activity

CERN Document Server

Pulinets, S A

2002-01-01

The potential difference near 280 kV exists between ground and ionosphere. This potential difference is generated by thunderstorm discharges all over the world, and return current closes the circuit in the areas of fair weather (so-called fair weather current). The model calculations and experimental measurements clearly demonstrate non-uniform latitude-longitude distribution of electric field within the atmosphere. The recent calculations show that the strong large scale vertical atmospheric electric field can penetrate into the ionosphere and create large scale irregularities of the electron concentration. To check this the global distributions of thunderstorm activity obtained with the satellite monitoring for different seasons were compared with the global distributions of ionosphere critical frequency (which is equivalent to peak electron concentration) obtained with the help of satellite topside sounding. The similarity of the obtained global distributions clearly demonstrates the effects of thunderstor...

Irregular Migration - between legal status and social practices

DEFF Research Database (Denmark)

Lund Thomsen, Trine

2012-01-01

Arnfinn H. and Rogstad, Jon 2.Book reviews by null 3.INVISIBLE IMMIGRANTS, VISIBLE EXPATS? Americans in Finnish discourses on immigration and internationalization by Leinonen, Johanna 4.Migrants in the Scandinavian Welfare State by Brochmann, Grete and Hagelund, Anniken 5.TOWARD AN IDENTITY STRESS....... Language and religious affiliations of an immigrant adolescent in Norway by Haque, Shahzaman View Top 20 Most Downloaded Articles Previous Article Next Article Go to table of contents Download full text pdf (PDF, 425 KB) Irregular Migration – Between Legal Status and Social Practices Narratives of Polish...... connected to the specific area of activity and to the accumulated capital of the individual. The aim is to identify how opportunity structures affect the migration process and how migrants react to them depending on the available capital and biographical knowledge and experiences. The horizon of experience...

On total irregularity strength of caterpillar graphs with two leaves on each internal vertex

Science.gov (United States)

Rosyida, I.; Widodo; Indriati, D.

2018-04-01

Let G(V, E) be a graph. A function f from V(G)\\cup E(G) to the set {1, 2, …, k} is said to be a totally irregular total k-labeling of G if the weights of any two different vertices x and y in V (G) satisfy {w}f(x)\

A Novel Respiratory Motion Perturbation Model Adaptable to Patient Breathing Irregularities

Energy Technology Data Exchange (ETDEWEB)

Yuan, Amy [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Wei, Jie [Department of Computer Science, City College of New York, New York, New York (United States); Gaebler, Carl P.; Huang, Hailiang; Olek, Devin [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States); Li, Guang, E-mail: lig2@mskcc.org [Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, New York (United States)

2016-12-01

Purpose: To develop a physical, adaptive motion perturbation model to predict tumor motion using feedback from dynamic measurement of breathing conditions to compensate for breathing irregularities. Methods and Materials: A novel respiratory motion perturbation (RMP) model was developed to predict tumor motion variations caused by breathing irregularities. This model contained 2 terms: the initial tumor motion trajectory, measured from 4-dimensional computed tomography (4DCT) images, and motion perturbation, calculated from breathing variations in tidal volume (TV) and breathing pattern (BP). The motion perturbation was derived from the patient-specific anatomy, tumor-specific location, and time-dependent breathing variations. Ten patients were studied, and 2 amplitude-binned 4DCT images for each patient were acquired within 2 weeks. The motion trajectories of 40 corresponding bifurcation points in both 4DCT images of each patient were obtained using deformable image registration. An in-house 4D data processing toolbox was developed to calculate the TV and BP as functions of the breathing phase. The motion was predicted from the simulation 4DCT scan to the treatment 4DCT scan, and vice versa, resulting in 800 predictions. For comparison, noncorrected motion differences and the predictions from a published 5-dimensional model were used. Results: The average motion range in the superoinferior direction was 9.4 ± 4.4 mm, the average ΔTV ranged from 10 to 248 mm{sup 3} (−26% to 61%), and the ΔBP ranged from 0 to 0.2 (−71% to 333%) between the 2 4DCT scans. The mean noncorrected motion difference was 2.0 ± 2.8 mm between 2 4DCT motion trajectories. After applying the RMP model, the mean motion difference was reduced significantly to 1.2 ± 1.8 mm (P=.0018), a 40% improvement, similar to the 1.2 ± 1.8 mm (P=.72) predicted with the 5-dimensional model. Conclusions: A novel physical RMP model was developed with an average accuracy of 1.2 ± 1.8 mm for

The Marine Corps Civil Military Operations (CMO) Capability: Inadequate for Current and Future Irregular Environments

Science.gov (United States)

2011-05-02

the 2011 National Military Strategy contend and numerous analysts posit, that the United States will continue to prosecute irregular warfare or a...think tank reports, and the ruminations of various luminaries that the United States will be involved in inegular wmfare throughout the remainder of

ARCAD3-SAFARI coordinated study of auroral and polar F-region ionospheric irregularities

International Nuclear Information System (INIS)

Villain, J.P.; Hanuise, C.

1986-01-01

Simultaneous observations of F-region ionospheric irregularities have been performed with the SAFARI ground-based HF radars and the ISOPROBE experiment on board the AUREOL-3 satellite. Among seven orbits during which the satellite trajectory was directly in the radar beam or in the vicinity, four of them have been analyzed in detail. The spectral power of the electron density variations ΔNsub(e)/Nsub(e) has been calculated for wavelengths between 20 m and 1 km from the isoprobe high time resolution thermal plasma measurements. One spectrum is obtained every 1.2 s, a time which corresponds to about 10 km along the satellite trajectory. The presence of echoes observed in the F-region with the SAFARI radars is compared with the spectral power of the electron density variations deduced from the ISOPROBE ''in situ'' measurements. A good agreement is found between the two sets of observations and a numerical value of the spectral power corresponding to detection of echoes by the radar is given. A synoptical view of the event is given and interpreted according to the existing theories of plasma irregularities

A Strategy of Attrition through Enforcement: The Unmaking of Irregular Migration in Malaysia

OpenAIRE

Choo Chin Low

2017-01-01

This article reviews Malaysia's attempt to achieve zero migration irregularity by focusing on workplace enforcement, and examines how Malaysia's migration control has become a struggle between the state and employers. Applying the framework of "enforcement through attrition", this research examines three newly introduced principles governing workplace enforcement: employer sanctions, the Strict Liability Principle, and the Employers' Mandatory Commitment. The shift to employers in Malaysia's ...

Achievable capacity design for irregular and clustered high performance mesh networks

CSIR Research Space (South Africa)

Olwal, TO

2012-11-01

Full Text Available interference, it is assumed that no any two HPNs are placed within a radius less than 400 m at the edge and less than 700 m toward the centre of the deployment area. However, between any two HPNs the largest separation distance is allowed as much possible... q mc p bit-meters/sec when cm = O(n). Proof : Let us consider that in irregular and static networks, the node den- sity varies over space (i.e., an area) but stays constant over time. Suppose the regularity rate (probability) of HPN...

A survey of plasma irregularities as seen by the midlatitude Blackstone SuperDARN radar

Science.gov (United States)

Ribeiro, A. J.; Ruohoniemi, J. M.; Baker, J. B. H.; Clausen, L. B. N.; Greenwald, R. A.; Lester, M.

2012-02-01

The Super Dual Auroral Radar Network (SuperDARN) is a chain of HF radars that monitor plasma dynamics in the ionosphere. In recent years, SuperDARN has expanded to midlatitudes in order to provide enhanced coverage during geomagnetically active periods. A new type of backscatter from F region plasma irregularities with low Doppler velocity has been frequently observed on the nightside during quiescent conditions. Using three years of data from the Blackstone, VA radar, we have implemented a method for extracting this new type of backscatter from routine observations. We have statistically characterized the occurrence properties of the Sub Auroral Ionospheric Scatter (SAIS) events, including the latitudinal relationships to the equatorward edge of the auroral oval and the ionospheric projection of the plasmapause. We find that the backscatter is confined to local night, occurs on ≈70% of nights, is fixed in geomagnetic latitude, and is equatorward of both the auroral region and the plasmapause boundary. We conclude that SAIS irregularities are observed within a range of latitudes that is conjugate to the inner magnetosphere (plasmasphere).

234Th/238U disequilibrium in near-shore sediment: particle reworking and diagenetic time scales

International Nuclear Information System (INIS)

Aller, R.C.; Cochran, J.K.

1976-01-01

The distribution of 234 Th (tsub(1.2)=24.1 days) in excess of its parent 238 U in the upper layers of near-shore sediment makes possible the evaluation of short-term sediment reworking and diagenetic rates. 234 Th has a maximum residence time in Long Island Sound water of 1.4 days. Seasonal measurement of 234 Th/ 238 U disequilibrium in sediment at a single station in central Long Island Sound demonstrates rapid particle reworking and high 234 Thsub(XS)(>1 dpm/g) in the upper 4 cm of sediment with slower, irregular reworking and low 234 Thsub(XS) to at least 12 cm. The rate of rapid particle reworking varies seasonally and is highest in the fall. The rapidly mixed zone is characterized by steep gradients in sediment chemistry implying fast reactions spanned by 234 Th decay time scales. 238 U is depleted in the upper mixed zone and shows addition in reducing sediment at depth. (Auth.)

Small-threshold behaviour of two-loop self-energy diagrams: two-particle thresholds

International Nuclear Information System (INIS)

Berends, F.A.; Davydychev, A.I.; Moskovskij Gosudarstvennyj Univ., Moscow; Smirnov, V.A.; Moskovskij Gosudarstvennyj Univ., Moscow

1996-01-01

The behaviour of two-loop two-point diagrams at non-zero thresholds corresponding to two-particle cuts is analyzed. The masses involved in a cut and the external momentum are assumed to be small as compared to some of the other masses of the diagram. By employing general formulae of asymptotic expansions of Feynman diagrams in momenta and masses, we construct an algorithm to derive analytic approximations to the diagrams. In such a way, we calculate several first coefficients of the expansion. Since no conditions on relative values of the small masses and the external momentum are imposed, the threshold irregularities are described analytically. Numerical examples, using diagrams occurring in the standard model, illustrate the convergence of the expansion below the first large threshold. (orig.)

Modelling the Cost Performance of a Given Logistics Network Operating Under Regular and Irregular Conditions

NARCIS (Netherlands)

Janic, M.

2009-01-01

This paper develops an analytical model for the assessment of the cost performance of a given logistics network operating under regular and irregular (disruptive) conditions. In addition, the paper aims to carry out a sensitivity analysis of this cost with respect to changes of the most influencing

Tremor irregularity, torque steadiness and rate of force development in Parkinson's disease

DEFF Research Database (Denmark)

Rose, Martin Høyer; Løkkegaard, Annemette; Sonne-Holm, Stig

2013-01-01

with idiopathic PD and 15 neurologically healthy matched controls performed isometric maximal contractions (extension/flexion) as well as steady submaximal and powerful isometric knee extensions. The patients with PD showed decreased isometric tremor irregularity. Torque steadiness was reduced in PD...... that both knee isometric tremor Approximate Entropy and torque steadiness clearly differentiate between patients with PD and healthy controls. Furthermore, severely compromised RFD was found in patients with PD and was associated with decreased agonist muscle activation....

Science and technology of kernels and TRISO coated particle sorting

International Nuclear Information System (INIS)

Nothnagel, G.

2006-09-01

The ~1mm diameter TRISO coated particles, which form the elemental units of PBMR nuclear fuel, has to be close to spherical in order to best survive damage during sphere pressing. Spherical silicon carbide layers further provide the strongest miniature pressure vessels for fission product retention. To make sure that the final product contains particles of acceptable shape, 100% of kernels and coated particles have to be sorted on a surface-ground sorting table. Broken particles, twins, irregular (odd) shapes and extreme ellipsoids have to be separated from the final kernel and coated particle batches. Proper sorting of particles is an extremely important step in quality fuel production as the final failure fraction depends sensitively on the quality of sorting. After sorting a statistically significant sample of the sorted product is analysed for sphericity, which is defined as the ratio of maximum to minimum diameter, as part of a standard QC test to ensure conformance to German specifications. In addition a burn-leach test is done on coated particles (before pressing) and fuel spheres (after pressing) to ensure adherence to failure specifications. Because of the extreme importance of particle sorting for assurance of fuel quality it is essential to have an in-depth understanding of the capabilities and limitations of particle sorting. In this report a systematic scientific rationale is developed, from fundamental principles, to provide a basis for understanding the relationship between product quality and sorting parameters. The principles and concepts, developed in this report, will be of importance when future sorting tables (or equivalents) are to be designed. A number of new concepts and methodologies are developed to assist with equivalence validation of any two sorting tables. This is aimed in particular towards quantitative assessment of equivalence between current QC tables (closely based on the original NUKEM parameters, except for the driving mechanism

Experimental relationship between the specific resistance of a HEPA [High Efficiency Particulate Air] filter and particle diameters of different aerosol materials

International Nuclear Information System (INIS)

Novick, V.J.; Monson, P.R.; Ellison, P.E.

1990-01-01

The increase in pressure drop across a HEPA filter has been measured as a function of the particle mass loading using two materials with different particle morphologies. The HEPA filter media chosen, is identical to the filter media used in the Airborne Activity Confinement System (AACS) on the Savannah River Reactors. The velocity through the test filter media was the same as the velocity through the AACS media, under normal operating flow conditions. Sodium Chloride challenge particles were generated using an atomizer, resulting in regularly shaped crystalline forms. Ammonium chloride aerosols were formed from the gas phase reaction of HCl and NH 4 OH vapors resulting in irregular agglomerates. In both cases, the generation conditions were adjusted to provide several different particle size distributions. For each particle size distribution, the mass of material loaded per unit area of filter per unit pressure drop for a given filtration velocity (1/Specific resistance) was measured. Theoretical considerations in the most widely accepted filter cake model predict that the mass per unit area and per unit pressure drop should increase with the particle density times the particle diameter squared. However, these test results indicate that the increase in the mass loaded per unit area per unit pressure drop, for both materials, can be better described by plotting the specific resistance divided by the particle density as an inverse function of the particle density times the particle diameter squared. 9 refs., 7 figs

Observational study of ionospheric irregularities and GPS scintillations associated with the 2012 tropical cyclone Tembin passing Hong Kong

Science.gov (United States)

Yang, Zhe; Liu, Zhizhao

2016-05-01

This study presents the ionospheric responses observed in Hong Kong to a Typhoon, namely, Tembin, from the aspects of the occurrence of ionospheric irregularities and scintillations, using Global Positioning System (GPS) observations from a ground-based GPS scintillation monitoring station in Hong Kong and from GPS receivers on board the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) satellites. The ionospheric irregularities and scintillations are characterized by the rate of total electron content variation index (ROTI) and the amplitude scintillation index S4, respectively. The typhoon Tembin formed over the western North Pacific during 18-30 August 2012 and approached Hong Kong during 24-27 August 2012 with the closest distance 290 km from Hong Kong at around 17 universal time (UT) on 25 August 2012. The ground-based observations indicate that in the nighttime period of 20:00-02:00 local time (LT = UT + 8 h) on 26 August when Tembin passed closely to Hong Kong, the ionospheric irregularities and scintillations of GPS signals were observed in the south of Hong Kong, over the area of 13°N ~ 23°N in latitude and 110°E ~ 120°E in longitude. From the COSMIC observations, it shows that the number of radio occultation scintillation events peaks on 26 August 2012 during the passage of Tembin. Without the presence of strong geomagnetic or solar activity, it is suspected that gravity waves might be generated in the lower atmosphere and likely seed the formation of ionospheric plasma irregularities. This work for the first time from Hong Kong observes the sign of coupling between the lower atmosphere and ionosphere in a tropical cyclone event, combining both ground- and space-based GPS observation data.

Regularities and irregularities in order flow data

Science.gov (United States)

Theissen, Martin; Krause, Sebastian M.; Guhr, Thomas

2017-11-01

We identify and analyze statistical regularities and irregularities in the recent order flow of different NASDAQ stocks, focusing on the positions where orders are placed in the order book. This includes limit orders being placed outside of the spread, inside the spread and (effective) market orders. Based on the pairwise comparison of the order flow of different stocks, we perform a clustering of stocks into groups with similar behavior. This is useful to assess systemic aspects of stock price dynamics. We find that limit order placement inside the spread is strongly determined by the dynamics of the spread size. Most orders, however, arrive outside of the spread. While for some stocks order placement on or next to the quotes is dominating, deeper price levels are more important for other stocks. As market orders are usually adjusted to the quote volume, the impact of market orders depends on the order book structure, which we find to be quite diverse among the analyzed stocks as a result of the way limit order placement takes place.

Design strategies for irregularly adapting parallel applications

International Nuclear Information System (INIS)

Oliker, Leonid; Biswas, Rupak; Shan, Hongzhang; Sing, Jaswinder Pal

2000-01-01

Achieving scalable performance for dynamic irregular applications is eminently challenging. Traditional message-passing approaches have been making steady progress towards this goal; however, they suffer from complex implementation requirements. The use of a global address space greatly simplifies the programming task, but can degrade the performance of dynamically adapting computations. In this work, we examine two major classes of adaptive applications, under five competing programming methodologies and four leading parallel architectures. Results indicate that it is possible to achieve message-passing performance using shared-memory programming techniques by carefully following the same high level strategies. Adaptive applications have computational work loads and communication patterns which change unpredictably at runtime, requiring dynamic load balancing to achieve scalable performance on parallel machines. Efficient parallel implementations of such adaptive applications are therefore a challenging task. This work examines the implementation of two typical adaptive applications, Dynamic Remeshing and N-Body, across various programming paradigms and architectural platforms. We compare several critical factors of the parallel code development, including performance, programmability, scalability, algorithmic development, and portability

Multiresolution Analysis Adapted to Irregularly Spaced Data

Directory of Open Access Journals (Sweden)

Anissa Mokraoui

2009-01-01

Full Text Available This paper investigates the mathematical background of multiresolution analysis in the specific context where the signal is represented by irregularly sampled data at known locations. The study is related to the construction of nested piecewise polynomial multiresolution spaces represented by their corresponding orthonormal bases. Using simple spline basis orthonormalization procedures involves the construction of a large family of orthonormal spline scaling bases defined on consecutive bounded intervals. However, if no more additional conditions than those coming from multiresolution are imposed on each bounded interval, the orthonormal basis is represented by a set of discontinuous scaling functions. The spline wavelet basis also has the same problem. Moreover, the dimension of the corresponding wavelet basis increases with the spline degree. An appropriate orthonormalization procedure of the basic spline space basis, whatever the degree of the spline, allows us to (i provide continuous scaling and wavelet functions, (ii reduce the number of wavelets to only one, and (iii reduce the complexity of the filter bank. Examples of the multiresolution implementations illustrate that the main important features of the traditional multiresolution are also satisfied.

Global scale ionospheric irregularities associated with thunderstorm activity

International Nuclear Information System (INIS)

Pulinets, Sergey A.; Depuev, Victor H.

2003-01-01

The potential difference near 280 kV exists between ground and ionosphere. This potential difference is generated by thunderstorm discharges all over the world, and return current closes the circuit in the areas of fair weather (so-called fair weather current). The model calculations and experimental measurements clearly demonstrate non-uniform latitude-longitude distribution of electric field within the atmosphere. The recent calculations show that the strong large scale vertical atmospheric electric field can penetrate into the ionosphere and create large scale irregularities of the electron concentration. To check this the global distributions of thunderstorm activity obtained with the satellite monitoring for different seasons were compared with the global distributions of ionosphere critical frequency (which is equivalent to peak electron concentration) obtained with the help of satellite topside sounding. The similarity of the obtained global distributions clearly demonstrates the effects of thunderstorm electric fields onto the Earth's ionosphere. (author)

Energetic efficiency, menstrual irregularity, and bone mineral density in elite professional female ballet dancers.

Science.gov (United States)

Doyle-Lucas, Ashley F; Akers, Jeremy D; Davy, Brenda M

2010-01-01

Sports that emphasize low body weight for optimal performance, such as ballet, are associated with an increased prevalence of the female athlete triad (FT). Previous research in this area that involves dancers has been limited; the majority of studies have been performed on adolescents training in classical ballet, and not professional adult dancers. The purpose of this study is to compare the physical and behavioral characteristics of female elite ballet dancers to sedentary, recreationally active non-dancing controls, with regard to characteristics of the FT and energetic efficiency. Women aged 18 to 35 years were recruited as participants. The dancers (N = 15) and non-dancing controls (N = 15) were pair-matched via age (dancers: 24.3 ± 1.3 years; controls: 23.7 ± 0.9 years), body mass index (dancers: 18.9 ± 0.2; controls: 19.4 ± 0.2 kg/m 2 ), and fat-free mass (dancers: 44.3 ± 0.8; controls: 44.1 ± 0.9 kg). Assessments included habitual dietary intake using 4-day food records, self-reported physical activity, psychometric measures of eating behaviors, health and menstrual history, body composition and bone density (dual energy x-ray absorptiometry), and resting metabolic rate (RMR) assessed by indirect calorimetry. Characteristics of the FT, specifically menstrual irregularities (6 of 15 dancers reported irregular or no menses; 1 of 15 controls reported irregular menses) and low energy availability, were more prevalent in dancers than in pair-matched controls. Despite having a similar fat-free mass (FFM), dancers had a significantly lower absolute RMR (dancers: 1367 ± 27; controls: 1454 ± 34 kcal/d; p ≤ 0.05) and significantly lower RMR relative to FFM (dancers: 30.9 ± 0.6; controls: 33.1 ± 0.8 kcal/kg fat-free mass/d; p ≤ 0.05). Energy intake between dancers (1577 ± 89 kcal/d) and pair-matched controls (2075 ± 163 kcal/d) also differed significantly (p ≤ 0.01). Six of the 15 dancers met the criteria for the FT (including low bone mineral