Density perturbations due to the inhomogeneous discrete spatial structure of space-time

International Nuclear Information System (INIS)

Wolf, C.

1998-01-01

For the case that space-time permits an inhomogeneous discrete spatial structure due to varying gravitational fields or a foam-like structure of space-time, it is demonstrated that thermodynamic reasoning implies that matter-density perturbations will arise in the early universe

Effect of dewatering on seismic performance of multi-anchor wall due to high ground water level

Science.gov (United States)

Kobayashi, Makoto; Miura, Kinya; Konami, Takeharu; Hayashi, Taketo; Sato, Hiroki

2017-10-01

Previous research reported that the ground water in the backfill of reinforced soil wall made it deteriorate. According to the damage investigation of Great East Earthquake 2011, the reinforced soil structure due to high ground water level by seismic wave were deformed remarkably. Some of them classified ultimate limit state or restorability limit state. However, more than 90% of reinforced soil structure, which suffered from this earthquake, were classified into no damage condition. Therefore, it is necessary that the seismic behaviors of multi-anchor wall due to seepage flow should be clarified in order to adopt the performance-based design in such reinforced soil structure. In this study, a series of centrifugal shaking table tests were conducted to investigate the seismic behavior of multi-anchor wall due to high ground water level. The reinforced drainage pipes were installed into the backfill in order to verify the dewatering effect and additional reinforcement. Furthermore, to check only the dewatering effect, the model tests was carried out with several ground water table that was modeled the case reinforced drainage pipes installed. The test results show unique behavior of reinforced region that moved integrally. This implies that the reinforced region has been behaved as if it became one mass, and this behavior make this structure increase seismic performance. Thus, the effectiveness of dewatering was observed remarkably because of decreasing the inertial force during earthquake.

Structural changes in a copper alloy due to helium implantation

International Nuclear Information System (INIS)

Moreno, D.; Eliezer, D.

1996-01-01

The most suitable nuclear fusion reaction for energy production occurs between the two heavy hydrogen isotopes, deuterium and tritium. Structural materials in fusion reactors will be exposed to helium implantation over a broad range of energies. The deformation and partial exfoliation of surface layers due to hydrogen isotopes and helium contribute to the total erosion of the first wall. For this reason, one of the most important criteria in the choice of materials for the first wall of fusion reactors is the material's damage resistance. Recent advances in developing nuclear fusion reactors reveal that efficient heat removal from plasma-facing components is very important. Copper and copper alloys are considered an attractive choice for transporting such a high heat flux without thermal damage as they have high thermal conductivity. In the present study the authors report on the structural changes in a copper alloy, due to the helium implantation on the very near surface area, observed by transmission electron microscopy

Structure soil structure interaction effects: Seismic analysis of safety related collocated concrete structures

International Nuclear Information System (INIS)

Joshi, J.R.

2000-01-01

The Process, Purification and Stack Buildings are collocated safety related concrete shear wall structures with plan dimensions in excess of 100 feet. An important aspect of their seismic analysis was the determination of structure soil structure interaction (SSSI) effects, if any. The SSSI analysis of the Process Building, with one other building at a time, was performed with the SASSI computer code for up to 50 frequencies. Each combined model had about 1500 interaction nodes. Results of the SSSI analysis were compared with those from soil structure interaction (SSI) analysis of the individual buildings, done with ABAQUS and SASSI codes, for three parameters: peak accelerations, seismic forces and the in-structure floor response spectra (FRS). The results may be of wider interest due to the model size and the potential applicability to other deep soil layered sites. Results obtained from the ABAQUS analysis were consistently higher, as expected, than those from the SSI and SSSI analyses using the SASSI. The SSSI effect between the Process and Purification Buildings was not significant. The Process and Stack Building results demonstrated that under certain conditions a massive structure can have an observable effect on the seismic response of a smaller and less stiff structure

The Analytical Pragmatic Structure of Procedural Due Process: A Framework for Inquiry in Administrative Decision Making.

Science.gov (United States)

Fisher, James E.; Sealey, Ronald W.

The study describes the analytical pragmatic structure of concepts and applies this structure to the legal concept of procedural due process. This structure consists of form, purpose, content, and function. The study conclusions indicate that the structure of the concept of procedural due process, or any legal concept, is not the same as the…

Contamination Effects Due to Space Environmental Interactions

Science.gov (United States)

Chen, Philip T.; Paquin, Krista C. (Technical Monitor)

2001-01-01

Molecular and particulate contaminants are commonly generated from the orbital spacecraft operations that are under the influence of the space environment. Once generated, these contaminants may attach to the surfaces of the spacecraft or may remain in the vicinity of the spacecraft. In the event these contaminants come to rest on the surfaces of the spacecraft or situated in the line-of-sight of the observation path, they will create various degrees of contamination effect which may cause undesirable effects for normal spacecraft operations, There will be circumstances in which the spacecraft may be subjected to special space environment due to operational conditions. Interactions between contaminants and special space environment may alter or greatly increase the contamination effect due to the synergistic effect. This paper will address the various types of contamination generation on orbit, the general effects of the contamination on spacecraft systems, and the typical impacts on the spacecraft operations due to the contamination effect. In addition, this paper will explain the contamination effect induced by the space environment and will discuss the intensified contamination effect resulting from the synergistic effect with the special space environment.

Structural alterations in rat liver proteins due to streptozotocin-induced diabetes and the recovery effect of selenium: Fourier transform infrared microspectroscopy and neural network study

Science.gov (United States)

Bozkurt, Ozlem; Haman Bayari, Sevgi; Severcan, Mete; Krafft, Christoph; Popp, Jürgen; Severcan, Feride

2012-07-01

The relation between protein structural alterations and tissue dysfunction is a major concern as protein fibrillation and/or aggregation due to structural alterations has been reported in many disease states. In the current study, Fourier transform infrared microspectroscopic imaging has been used to investigate diabetes-induced changes on protein secondary structure and macromolecular content in streptozotocin-induced diabetic rat liver. Protein secondary structural alterations were predicted using neural network approach utilizing the amide I region. Moreover, the role of selenium in the recovery of diabetes-induced alterations on macromolecular content and protein secondary structure was also studied. The results revealed that diabetes induced a decrease in lipid to protein and glycogen to protein ratios in diabetic livers. Significant alterations in protein secondary structure were observed with a decrease in α-helical and an increase in β-sheet content. Both doses of selenium restored diabetes-induced changes in lipid to protein and glycogen to protein ratios. However, low-dose selenium supplementation was not sufficient to recover the effects of diabetes on protein secondary structure, while a higher dose of selenium fully restored diabetes-induced alterations in protein structure.

Greenhouse effect due to atmospheric nitrous oxide

Science.gov (United States)

Yung, Y. L.; Wang, W. C.; Lacis, A. A.

1976-01-01

The greenhouse effect due to nitrous oxide in the present atmosphere is about 0.8 K. Increase in atmospheric N2O due to perturbation of the nitrogen cycle by man may lead to an increase in surface temperature as large as 0.5 K by 2025, or 1.0 K by 2100. Other climatic effects of N2O are briefly discussed.

Submarine slope failures due to pipe structure formation.

Science.gov (United States)

Elger, Judith; Berndt, Christian; Rüpke, Lars; Krastel, Sebastian; Gross, Felix; Geissler, Wolfram H

2018-02-19

There is a strong spatial correlation between submarine slope failures and the occurrence of gas hydrates. This has been attributed to the dynamic nature of gas hydrate systems and the potential reduction of slope stability due to bottom water warming or sea level drop. However, 30 years of research into this process found no solid supporting evidence. Here we present new reflection seismic data from the Arctic Ocean and numerical modelling results supporting a different link between hydrates and slope stability. Hydrates reduce sediment permeability and cause build-up of overpressure at the base of the gas hydrate stability zone. Resulting hydro-fracturing forms pipe structures as pathways for overpressured fluids to migrate upward. Where these pipe structures reach shallow permeable beds, this overpressure transfers laterally and destabilises the slope. This process reconciles the spatial correlation of submarine landslides and gas hydrate, and it is independent of environmental change and water depth.

Mechanisms and effects of lightning current coupling to structures

International Nuclear Information System (INIS)

Foboda, Marek

1999-01-01

To evaluate the effects of a lightning discharge on a structure, it is necessary to know the modes of interaction of lightning electromagnetic field pulses to structures. The effects to these interactions are considered by means to the concept to equivalent collection areas. The equations to calculate the distance and equivalent collection areas due to lightning discharges are given in this article. Additionally, the possible modes of a direct lightning strike to the incoming line and the equations to calculate the resultant over voltages are also given. This article ends with the calculation of voltage drops due to direct and nearby lightning strike and induced voltages due to magnetic coupling. Several examples of calculations of the different mentioned cases are given

Vibrations of composite circular shell structures due to transient loads

International Nuclear Information System (INIS)

Schrader, K.-H.; Krutzik, N.; Winkel, G.

1975-01-01

Referring to a container consisting of different shell structures - such as spherical, cylindrical and conical shells - the dynamic behavior of coupled spatial shell structures due to transient loads will be investigated. The spatial structure including the filling of water will be idealized as a three-dimensional model consisting of ring elements. The influence of the water filling on the vibrations will be considered by virtual masses added to the shell structures. In circular direction as well as in meridional direction a consistent mass model has been used. By variation of the virtual masses it will be clarified, how these additional masses influence the vibrational behavior of the composed system. Another aspect which will be investigated is the influence of different stiffnesses of substructures or parts of substructures on the natural frequencies, and on their affiliated eigensystems. Furthermore, the maximum and minimum stresses in the structures caused by transient loads acting on the inner surface of the shells will be explored. Here it seems to be possible to locate an area of maximum strain. Rotational loads as well as nonrotational loads will be considered

Solving Component Structural Dynamic Failures Due to Extremely High Frequency Structural Response on the Space Shuttle Program

Science.gov (United States)

Frady, Greg; Nesman, Thomas; Zoladz, Thomas; Szabo, Roland

2010-01-01

For many years, the capabilities to determine the root-cause failure of component failures have been limited to the analytical tools and the state of the art data acquisition systems. With this limited capability, many anomalies have been resolved by adding material to the design to increase robustness without the ability to determine if the design solution was satisfactory until after a series of expensive test programs were complete. The risk of failure and multiple design, test, and redesign cycles were high. During the Space Shuttle Program, many crack investigations in high energy density turbomachines, like the SSME turbopumps and high energy flows in the main propulsion system, have led to the discovery of numerous root-cause failures and anomalies due to the coexistences of acoustic forcing functions, structural natural modes, and a high energy excitation, such as an edge tone or shedding flow, leading the technical community to understand many of the primary contributors to extremely high frequency high cycle fatique fluid-structure interaction anomalies. These contributors have been identified using advanced analysis tools and verified using component and system tests during component ground tests, systems tests, and flight. The structural dynamics and fluid dynamics communities have developed a special sensitivity to the fluid-structure interaction problems and have been able to adjust and solve these problems in a time effective manner to meet budget and schedule deadlines of operational vehicle programs, such as the Space Shuttle Program over the years.

Structural degradation of acrylic bone cements due to in vivo and simulated aging.

Science.gov (United States)

Hughes, Kerry F; Ries, Michael D; Pruitt, Lisa A

2003-05-01

Acrylic bone cement is the primary load-bearing material used for the attachment of orthopedic devices to adjoining bone. Degradation of acrylic-based cements in vivo results in a loss of structural integrity of the bone-cement-prosthesis interface and limits the longevity of cemented orthopedic implants. The purpose of this study is to investigate the effect of in vivo aging on the structure of the acrylic bone cement and to develop an in vitro artificial aging protocol that mimics the observed degradation. Three sets of retrievals are examined in this study: Palacos brand cement retrieved from hip replacements, and Simplex brand cement retrieved from both hip and knee replacement surgeries. In vitro aging is performed using oxidative and acidic environments on three acrylic-based cements: Palacos, Simplex, and CORE. Gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR) are used to examine the evolution of molecular weight and chemical species within the acrylic cements due to both in vivo and simulated aging. GPC analysis indicates that molecular weight is degraded in the hip retrievals but not in the knee retrievals. Artificial aging in an oxidative environment best reproduces this degradation mechanism. FTIR analysis indicates that there exists a chemical evolution within the cement due to in vivo and in vitro aging. These findings are consistent with scission-based degradation schemes in the cement. Based on the results of this study, a pathway for structural degradation of acrylic bone cement is proposed. The findings from this investigation have broad applicability to acrylic-based cements and may provide guidance for the development of new bone cements that resist degradation in the body. Copyright 2003 Wiley Periodicals, Inc.

Neighborhood structure effects on the Dynamic response of soil-structure interaction by harmonic analysis

Directory of Open Access Journals (Sweden)

Pan Dan-guang

2015-01-01

Full Text Available For realizing the variation of structural dynamic characteristics due to neighbor structure in buildings group, the surface structure is idealized as an equivalent single degree of freedom system with rigid base whose site consists of a single homogeneous layer. Based on the model, a equivalent method on the equivalent seismic excitation is proposed. Then, the differences of seismic response and equivalent seismic input between soil - structure interaction (SSI system and structure -soil-structure interaction (SSSI system are investigated by harmonic analysis. The numerical results show that dynamic responses would be underestimated in SSSI system when the forcing frequencies are close to the Natural frequency if the effects of neighborhood structure were ignored. Neighborhood structure would make the translational displacement increase and rocking vibration decrease. When establishing an effective seismic input, it is necessary to consider the impact of inertia interaction.

Uncertainty in Earthquake Source Imaging Due to Variations in Source Time Function and Earth Structure

KAUST Repository

Razafindrakoto, H. N. T.; Mai, Paul Martin

2014-01-01

One way to improve the accuracy and reliability of kinematic earthquake source imaging is to investigate the origin of uncertainty and to minimize their effects. The difficulties in kinematic source inversion arise from the nonlinearity of the problem, nonunique choices in the parameterization, and observational errors. We analyze particularly the uncertainty related to the choice of the source time function (STF) and the variability in Earth structure. We consider a synthetic data set generated from a spontaneous dynamic rupture calculation. Using Bayesian inference, we map the solution space of peak slip rate, rupture time, and rise time to characterize the kinematic rupture in terms of posterior density functions. Our test to investigate the effect of the choice of STF reveals that all three tested STFs (isosceles triangle, regularized Yoffe with acceleration time of 0.1 and 0.3 s) retrieve the patch of high slip and slip rate around the hypocenter. However, the use of an isosceles triangle as STF artificially accelerates the rupture to propagate faster than the target solution. It additionally generates an artificial linear correlation between rupture onset time and rise time. These appear to compensate for the dynamic source effects that are not included in the symmetric triangular STF. The exact rise time for the tested STFs is difficult to resolve due to the small amount of radiated seismic moment in the tail of STF. To highlight the effect of Earth structure variability, we perform inversions including the uncertainty in the wavespeed only, and variability in both wavespeed and layer depth. We find that little difference is noticeable between the resulting rupture model uncertainties from these two parameterizations. Both significantly broaden the posterior densities and cause faster rupture propagation particularly near the hypocenter due to the major velocity change at the depth where the fault is located.

Uncertainty in Earthquake Source Imaging Due to Variations in Source Time Function and Earth Structure

KAUST Repository

Razafindrakoto, H. N. T.

2014-03-25

One way to improve the accuracy and reliability of kinematic earthquake source imaging is to investigate the origin of uncertainty and to minimize their effects. The difficulties in kinematic source inversion arise from the nonlinearity of the problem, nonunique choices in the parameterization, and observational errors. We analyze particularly the uncertainty related to the choice of the source time function (STF) and the variability in Earth structure. We consider a synthetic data set generated from a spontaneous dynamic rupture calculation. Using Bayesian inference, we map the solution space of peak slip rate, rupture time, and rise time to characterize the kinematic rupture in terms of posterior density functions. Our test to investigate the effect of the choice of STF reveals that all three tested STFs (isosceles triangle, regularized Yoffe with acceleration time of 0.1 and 0.3 s) retrieve the patch of high slip and slip rate around the hypocenter. However, the use of an isosceles triangle as STF artificially accelerates the rupture to propagate faster than the target solution. It additionally generates an artificial linear correlation between rupture onset time and rise time. These appear to compensate for the dynamic source effects that are not included in the symmetric triangular STF. The exact rise time for the tested STFs is difficult to resolve due to the small amount of radiated seismic moment in the tail of STF. To highlight the effect of Earth structure variability, we perform inversions including the uncertainty in the wavespeed only, and variability in both wavespeed and layer depth. We find that little difference is noticeable between the resulting rupture model uncertainties from these two parameterizations. Both significantly broaden the posterior densities and cause faster rupture propagation particularly near the hypocenter due to the major velocity change at the depth where the fault is located.

Effect of gravity loading on inelastic seismic response of reinforced concrete structures

International Nuclear Information System (INIS)

Chowdhury, Rajib; Reddy, G. Rami; Roy, Raghupati; Dutta, Sekhar Chandra

2003-01-01

The effect of gravity loading is not considered in inelastic seismic response to avoid complexity and to reduce the number of influencing parameters. However, the possibility of considerable effect of this factor is indicated in many studies on inelastic seismic behaviour of structures. Hence, it is necessary to study the nature and extent of this effect on inelastic seismic behaviour of structures. The present paper attempts to fulfill this objective by studying the variation of energy dissipation due to presence of various level of axial load. The study is further extended to see the effect of axial force due to gravity loading on the ductility demand of hysteretic energy demand arising in structural elements of a simple one storey structures. The study shows that the presence of axial force may increase the energy dissipation capacity of structure leading to a reduction in ductility demand. (author)

INTERNAL STRUCTURE OF ASTEROIDS HAVING SURFACE SHEDDING DUE TO ROTATIONAL INSTABILITY

Energy Technology Data Exchange (ETDEWEB)

Hirabayashi, Masatoshi [Research Associate, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States); Sánchez, Diego Paul [Senior Research Associate, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States); Scheeres, Daniel J., E-mail: masatoshi.hirabayashi@colorado.edu [Richard Seebass Chair, Professor, Colorado Center for Astrodynamics Research, Aerospace Engineering Sciences, University of Colorado Boulder (United States)

2015-07-20

Surface shedding of an asteroid is a failure mode where surface materials fly off due to strong centrifugal forces beyond the critical spin period, while the internal structure does not deform significantly. This paper proposes a possible structure of an asteroid interior that leads to surface shedding due to rapid rotation rates. A rubble pile asteroid is modeled as a spheroid composed of a surface shell and a concentric internal core, the entire assembly called the test body. The test body is assumed to be uniformly rotating around a constant rotation axis. We also assume that while the bulk density and the friction angle are constant, the cohesion of the surface shell is different from that of the internal core. First, developing an analytical model based on limit analysis, we provide the upper and lower bounds for the actual surface shedding condition. Second, we use a Soft-sphere Discrete Element Method (SSDEM) to study dynamical deformation of the test body due to a quasi-static spin-up. In this paper we show the consistency of both approaches. Additionally, the SSDEM simulations show that the initial failure always occurs locally and not globally. In addition, as the core becomes larger, the size of lofted components becomes smaller. These results imply that if there is a strong core in a progenitor body, surface shedding is the most likely failure mode.

INTERNAL STRUCTURE OF ASTEROIDS HAVING SURFACE SHEDDING DUE TO ROTATIONAL INSTABILITY

International Nuclear Information System (INIS)

Hirabayashi, Masatoshi; Sánchez, Diego Paul; Scheeres, Daniel J.

2015-01-01

Surface shedding of an asteroid is a failure mode where surface materials fly off due to strong centrifugal forces beyond the critical spin period, while the internal structure does not deform significantly. This paper proposes a possible structure of an asteroid interior that leads to surface shedding due to rapid rotation rates. A rubble pile asteroid is modeled as a spheroid composed of a surface shell and a concentric internal core, the entire assembly called the test body. The test body is assumed to be uniformly rotating around a constant rotation axis. We also assume that while the bulk density and the friction angle are constant, the cohesion of the surface shell is different from that of the internal core. First, developing an analytical model based on limit analysis, we provide the upper and lower bounds for the actual surface shedding condition. Second, we use a Soft-sphere Discrete Element Method (SSDEM) to study dynamical deformation of the test body due to a quasi-static spin-up. In this paper we show the consistency of both approaches. Additionally, the SSDEM simulations show that the initial failure always occurs locally and not globally. In addition, as the core becomes larger, the size of lofted components becomes smaller. These results imply that if there is a strong core in a progenitor body, surface shedding is the most likely failure mode

Numerical modelling of welding distortion redistribution due to the change of self-constraint in a T-joint welded structure

Energy Technology Data Exchange (ETDEWEB)

Wang, Chao; Kim, Yong Rae; Kim, Jae Woong [Yeungnam University, Kyongsan (Korea, Republic of)

2016-06-15

Finite element method (FEM) is a powerful tool for analysing the potential deformation during a material removal process. After the removal of material, re-establishment of equilibrium within the remaining part of the structure causes distortion due to the relief of residual stress in the removed materials. In this study, commercial FEM software (MSC.Marc) was used to simulate material removal, and the accuracy was evaluated by comparison with results from machining experiments. The effect of cutting height on the distortion redistribution and the kerf width in a T-joint welded structure is discussed, and the distortion differences at the centre line of the bottom were compared between the calculated and experimental results. The results demonstrate that the developed model is useful and efficient for simulating the redistribution of welding distortion due to material removal.

Surface structural damage study in cortical bone due to medical drilling.

Science.gov (United States)

Tavera R, Cesar G; De la Torre-I, Manuel H; Flores-M, Jorge M; Hernandez M, Ma Del Socorro; Mendoza-Santoyo, Fernando; Briones-R, Manuel de J; Sanchez-P, Jorge

2017-05-01

A bone's fracture could be produced by an excessive, repetitive, or sudden load. A regular medical practice to heal it is to fix it in two possible ways: external immobilization, using a ferule, or an internal fixation, using a prosthetic device commonly attached to the bone by means of surgical screws. The bone's volume loss due to this drilling modifies its structure either in the presence or absence of a fracture. To observe the bone's surface behavior caused by the drilling effects, a digital holographic interferometer is used to analyze the displacement surface's variations in nonfractured post-mortem porcine femoral bones. Several nondrilled post-mortem bones are compressed and compared to a set of post-mortem bones with a different number of cortical drillings. During each compression test, a series of digital interferometric holograms were recorded using a high-speed CMOS camera. The results are presented as pseudo 3D mesh displacement maps for comparisons in the physiological range of load (30 and 50 lbs) and beyond (100, 200, and 400 lbs). The high resolution of the optical phase gives a better understanding about the bone's microstructural modifications. Finally, a relationship between compression load and bone volume loss due to the drilling was observed. The results prove that digital holographic interferometry is a viable technique to study the conditions that avoid the surgical screw from loosening in medical procedures of this kind.

Structural failure analysis of reactor vessels due to molten core debris

International Nuclear Information System (INIS)

Pfeiffer, P.A.

1993-01-01

Maintaining structural integrity of the reactor vessel during a postulated core melt accident is an important safety consideration in the design of the vessel. This paper addresses the failure predictions of the vessel due to thermal and pressure loadings from the molten core debris depositing on the lower head of the vessel. Different loading combinations were considered based on a wet or dry cavity and pressurization of the vessel based on operating pressure or atmospheric (pipe break). The analyses considered both short term (minutes) and long term (days) failure modes. Short term failure modes include creep at elevated temperatures and plastic instabilities of the structure. Long term failure modes are caused by creep rupture that lead to plastic instability of the structure. The analyses predict the reactor vessel will remain intact after the core melt has deposited on the lower vessel head

Probabilistic analysis of the torsional effects on the tall building resistance due to earthquake even

Science.gov (United States)

Králik, Juraj; Králik, Juraj

2017-07-01

The paper presents the results from the deterministic and probabilistic analysis of the accidental torsional effect of reinforced concrete tall buildings due to earthquake even. The core-column structural system was considered with various configurations in plane. The methodology of the seismic analysis of the building structures in Eurocode 8 and JCSS 2000 is discussed. The possibilities of the utilization the LHS method to analyze the extensive and robust tasks in FEM is presented. The influence of the various input parameters (material, geometry, soil, masses and others) is considered. The deterministic and probability analysis of the seismic resistance of the structure was calculated in the ANSYS program.

Tempo discrimination of musical patterns: effects due to pitch and rhythmic structure.

Science.gov (United States)

Boltz, M G

1998-11-01

The purpose of this research was to investigate a set of factors that may influence the perceived rate of an auditory event. In a paired-comparison task, subjects were presented with a set of music-like patterns that differed in their relative number of contour changes and in the magnitude of pitch skips (Experiment 1) as well as in the compatibility of rhythmic accent structure with the arrangement of pitch relations (Experiment 2) Results indicated that, relative to their standard referents, comparison melodies were judged to unfold more slowly when they displayed more changes in pitch direction, greater pitch distances, and an incompatible rhythmic accent structure. These findings are suggested to stem from an imputed velocity hypothesis, in which people overgeneralize certain invariant relations that typically occur between melodic and temporal accent structure within Western music.

Measurement of the noise components in the medical x-ray intensity pattern due to overlaying nonrecognizable structures

Science.gov (United States)

Tischenko, Oleg; Hoeschen, Christoph; Effenberger, Olaf; Reissberg, Steffen; Buhr, Egbert; Doehring, Wilfried

2003-06-01

There are many aspects that influence and deteriorate the detection of pathologies in X-ray images. Some of those are due to effects taking place in the stage of forming the X-ray intensity pattern in front of the x-ray detector. These can be described as motion blurring, depth blurring, anatomical background, scatter noise and structural noise. Structural noise results from an overlapping of fine irrelevant anatomical structures. A method for measuring the combined effect of structural noise and scatter noise was developed and will be presented in this paper. This method is based on the consideration that within a pair of projections created after rotation of the object with a small angle (which is within the typical uncertainty in positioning the patient) both images would show the same relevant structures whereas the projection of the fine overlapping structures will appear quite differently in the two images. To demonstrate the method two X-ray radiographs of a lung phantom were produced. The second radiograph was achieved after rotating the lung by an angle of about 3. Dyadic wavelet representations of both images were regarded. For each value of the wavelet scale parameter the corresponding pair of approximations was matched using the cross correlation matching technique. The homologous regions of approximations were extracted. The image containing only those structures that appear in both images simultaneously was then reconstructed from the wavelet coefficients corresponding to the homologous regions. The difference between one of the original images and the noise-reduced image contains the structural noise and the scatter noise.

Equidistant structure and effective nucleon mass in nuclear matter

International Nuclear Information System (INIS)

Tezuka, Hirokazu.

1981-11-01

The effective nucleon mass of the Equidistant Multi-Layer Structure (EMULS) is discussed self-consistently. In the density region where the Fermi gas state in nuclear matter is unstable against the density fluctuation, the EMULS gives lower binding energy. It is, however, shown that such a structure with an ordinary nucleon mass collapses due to too strong attraction. We point out that such a collapse can be avoided by taking account of an effective nucleon mass affected by the localization of nucleons. (author)

Magnetoelectric Effect in Gallium Arsenide-Nickel-Tin-Nickel Multilayer Structures

Science.gov (United States)

Filippov, D. A.; Tikhonov, A. A.; Laletin, V. M.; Firsova, T. O.; Manicheva, I. N.

2018-02-01

Experimental data have been presented for the magnetoelectric effect in nickel-tin-nickel multilayer structures grown on a GaAs substrate by cathodic electrodeposition. The method of fabricating these structures has been described, and the frequency dependence of the effect has been demonstrated. It has been shown that tin used as an intermediate layer reduces mechanical stresses due to the phase mismatch at the Ni-GaAs interface and, thus, makes it possible to grow good structures with a 70-μm-thick Ni layer. The grown structures offer good adhesion between layers and a high Q factor.

Effects of the magnetic field on the structure of materials

International Nuclear Information System (INIS)

Nakajima, Tetsuo

1984-02-01

This is a report of the ''Meeting on the effects of a magnetic field on the structure of materials'' held at KEK, Japan. The purpose of the Meeting was to study the diffraction of SR X-ray in a magnetic field. It was found that the effects of a magnetic field have been seen in various substnaces. The effects are due to the Zeeman effect, the Lamor diamagnetism, the Landau diamagnetism, the Meissner effect and the polarization effect. The topics discussed at the Meeting were the structure study of biological specimens by field orientation, the study of cell structure by field orientation, the phase transition under a strong pulse field, the behavior of high molecular liquid crystal in a magnetic field, the change of the f-electron density of the Tb 3+ ions in Tb IG in a magnetic field at low temperature, an electromagnet loaded on a goniometer and an in-situ observation system for the structure of magnetic domain, the control of structural phase transition by a magnetic field, the use of synchrotron orbit radiation for the structural analysis of random systems, and the field effect on chemical reactions. (Kato, T.)

Numerical Study of Focusing Effects of Microwaves inside Wood Due to Timber Ring Structure

Directory of Open Access Journals (Sweden)

Rocio Sanchez-Montero

2018-02-01

Full Text Available The aim of this study is the detailed calculation of microwave propagation inside raw timber in cylindrical configurations. Two different approaches have been used. The first one uses an exact formulation and analytical approximations in order to explore the electromagnetic field distribution inside dry wood. The introduction of conductivity in the exact model makes it so complex that the equations are unsuitable for analytical manipulation. In order to further explore the effect of moisture in cylindrical wood structures, a full scale numerical simulation using commercial software has been performed. The results show that for microwave frequencies in the 3 GHz range and for typical wood parameters, a cylindrical log behaves as a kind of Fresnel lens. This work has important applications in microwave treatment and sensing of wood.

The effect of seismic energy scavenging on host structure and harvesting performance

International Nuclear Information System (INIS)

Lallart, Mickaël; Wu, Yi-Chieh; Yan, Linjuan; Richard, Claude; Guyomar, Daniel

2013-01-01

Cantilevered piezoelectric energy harvesters have been studied extensively in recent years. Numerous techniques have been investigated to achieve optimal power output. However, the extraction of electrical energy from mechanical vibration leads to a reduction of the vibration magnitude of the harvester because of the electromechanical coupling effect, and so a model considering constant vibration magnitude input is no longer valid. Thus, an energy harvesting model excited with a constant force or acceleration magnitude has been adopted to take into account the damping effect induced by the energy harvesting process. This paper extends this model to the effect of energy harvesting on the fixed host structure (mechanical to mechanical coupling). Theoretical developments are presented as a dynamic problem of an electromechanically coupled two-degree-of-freedom (TDOF) spring–mass–damper system. Then, experimental measurements and computations based on finite element modeling (FEM) are carried out to validate theoretical predictions. It is shown that the extracted power obtained from the TDOF model would reach a maximal value by tuning the mass ratio between the host structure and the harvester and optimizing the electric load. The mechanical to mechanical coupling effect due to the harvester leads to a trade-off between the mechanical energy of the host structure and the harvested energy. When the harvester mass to host structure mass ratio is around 10 −3 , the maximal power is obtained and the host structure then has a sudden displacement reduction due to the strong mechanical to mechanical coupling. Experimental measurements have been performed for a mass ratio of around 0.02, with which the harvester effect is not negligible on the host structure behavior as the host structure displacement shows a decrease of more than 3 dB. In addition, the harvested power calculated with the TDOF model is about two times less than with a single-degree-of-freedom (SDOF

Structural changes of cotton seeds due to fast neurons-irradiation

Energy Technology Data Exchange (ETDEWEB)

Osiris, W G [Biophysics Department, Faculty of Science, Cairo University, Giza, (Egypt)

1997-12-31

The effect of irradiation with different fast neutron fluences in the range 10{sub 5}- 10{sub 8} n/cm{sup 2} were studied on one egyptian cotton seeds (Dandara, Giza 31). Both pre-and post-irradiated seeds were implanted and the effects of fast neutrons on the first generation were investigated through the use of: X-ray fluorescence analysis, infrared spectral,combustion technique, analysis as well as scanning electron microscopy. The changes in cellulose and heme cellulose contents in the seeds relative to the unirradiated one were also detected. From the obtained results,it was found that significant structural changes are indicated which may be attributed to the variation in the internal mechanisms that occurred by the radiation effect on thr structure of seeds. In conclusion, irradiation with fast neutrons may cause genetic changes in seeds. 4 figs., 5 tabs.

Generation of Earthquake Ground Motion Considering Local Site Effects and Soil-Structure Interaction Analysis of Ancient Structures

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Kwan; Lee, J. S.; Yang, T. S.; Cho, J. R.; R, H. [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

1997-09-01

In order to establish a correct correlation between them, mechanical characteristics of the ancient structures need to be investigated. Since sedimentary basins are preferred dwelling sites in ancient times, it is necessary to perform SSI analysis to derive correct correlation between the damage and ground motion intensity. Contents of Project are as follows: (1) Generation of stochastic earthquake ground motion considering source mechanism and site effects. (2) Analysis of seismic response of sedimentary basin. (3) Soil-structure interaction analysis of ancient structures (4) Investigation of dynamic response characteristics of ancient structure considering soil-structure interaction effects. A procedure is presented for generation of stochastic earthquake ground motion considering source mechanism and site effects. The simulation method proposed by Boore is used to generate the outcropping rock motion. The free field motion at the soil site is obtained by a convolution analysis. And for the study of wood structures, a nonlinear SDOF model is developed. The effects of soil-structure interaction on the behavior of the wood structures are found to be very minor. But the response can be significantly affected due to the intensity and frequency contents of the input motion. 13 refs., 6 tabs., 31 figs. (author)

The effect of exchange-correlation on change and stability of crystal structure

International Nuclear Information System (INIS)

Yazdani, A.; Niazi, M.; Alimardan, V.

2007-01-01

Since exchange interaction energy has effect on band structure via polarization of spin of free electron, then can directly effects formation crystal structure. Therefore exchange-correlation is able to have an effect on determination of crystal structure or its change and stability. This energy is subject to fluctuation range of electrons between conduction band and valance band or density of electrons which due to increase the entropy of system, via Gibss Energy .We investigated these factors: 1) Size of ions 2) Density of States 3) Range of inter atomic and pair-potential.

Effect of high temperature on integrity of concrete containment structures

International Nuclear Information System (INIS)

Bhat, P.D.

1986-01-01

The effect of high temperature on concrete material properties and structural behavior are studied in order to relate these effects to the performance of concrete containment structures. Salient data obtained from a test program undertaken to study the behavior of a restrained concrete structure under thermal gradient loads up to its ultimate limit are described. The preliminary results indicate that concrete material properties can be considered to remain unaltered up to temperatures of 100 0 C. The presence of thermal gradients did not significantly affect the structures ultimate mechanical load capacity. Relaxation of restraint forces due to creep was found to be an important factor. The test findings are compared with the observations made in available literature. The effect of test findings on the integrity analysis of a containment structure are discussed. The problem is studied from the viewpoint of a CANDU heavy water reactor containment

Dynamic structural response of reactor-core subassemblies (hexcans) due to accident overpressurization

International Nuclear Information System (INIS)

Pfeiffer, P.A.; Kulak, R.F.

1993-01-01

This paper presents a two-dimensional structural analysis for the evaluation of a single core subassembly due to internal overpressure associated with possible failure of fuel pins having high fission gas plenum pressure. Structural models are developed for the subassemblies and their surroundings with emphasis on the critical physical aspects of the problem. With these models the strains, deformations and the extent of permanent damage (plastic strain) to the subassemblies can be assessed. The nonlinear structural analyses was performed with a finite element program called STRAW (Structural Transient Response of Assembly Wrappers). This finite element program is applicable to nonlinear large displacement problems. The results of this study indicate that the permanent deformation (damage) is strongly influenced by the rise time (time to reach peak pressure) of the pressure pulse and the pressure in the fuel pin. The rise time is influenced by the opening time of the flow path for release of gas from the fuel pin plenum. Several examples are illustrated with various rise times and pressure magnitudes and the resulting permanent deformation of the hexcan wall. (author)

Dynamic structural response of reactor-core subassemblies (hexcans) due to accident overpressurization

International Nuclear Information System (INIS)

Pfeiffer, P.A.; Kulak, R.F.

1993-01-01

This paper presents a two-dimensional structural analysis for the evaluation of a single core subassembly due to internal overpressure associated with possible failure of fuel pins having high fission gas plenum pressure. Structural models are developed for the subassemblies and their surroundings with emphasis on the critical physical aspects of the problem. With these models the strains, deformations and the extent of permanent damage (plastic strain) to the subassemblies can be assessed. The nonlinear structural analyses was performed with a finite element program called STRAW (Structural Transient Response of Assembly Wrappers). This finite element program is applicable to nonlinear large displacement problems. The results of this study indicate that the permanent deformation (damage) is strongly influenced by the rise time (time to reach peak pressure) of the pressure pulse and the pressure in the fuel pin. The rise time is influenced by the opening time of the flow path for release of gas from the fuel pin plenum. Several examples are illustrated with various rise times and pressure magnitudes and the resulting permanent deformation of the hexcan wall

Potential fluctuations due to the randomly distributed charges at the semiconductor-insulator interface in MIS-structures

International Nuclear Information System (INIS)

Slavcheva, G.; Yanchev, I.

1991-01-01

A new expression for the Fourier transform of the binary correlation function of the random potential near the semiconductor-insulator interface is derived. The screening due to the image charge with respect to the metal electrode in MIS-structure is taken into account, introducing an effective insulator thickness. An essential advantage of this correlation function is the finite dispersion of the random potential Γ 2 to which it leads in distinction with the so far known correlation functions leading to divergent dispersion. The important characteristic of the random potential distribution Γ 2 determining the amplitude of the potential fluctuations is calculated. (author). 7 refs, 1 fig

Enhancement of Transistor-to-Transistor Variability Due to Total Dose Effects in 65-nm MOSFETs

CERN Document Server

Gerardin, S; Cornale, D; Ding, L; Mattiazzo, S; Paccagnella, A; Faccio, F; Michelis, S

2015-01-01

We studied device-to-device variations as a function of total dose in MOSFETs, using specially designed test structures and procedures aimed at maximizing matching between transistors. Degradation in nMOSFETs is less severe than in pMOSFETs and does not show any clear increase in sample-to-sample variability due to the exposure. At doses smaller than 1 Mrad( SiO2) variability in pMOSFETs is also practically unaffected, whereas at very high doses-in excess of tens of Mrad( SiO2)-variability in the on-current is enhanced in a way not correlated to pre-rad variability. The phenomenon is likely due to the impact of random dopant fluctuations on total ionizing dose effects.

Soil-structure interaction effects in seismic analysis of turbine generator building on rock-like foundation

International Nuclear Information System (INIS)

Park, Chi Seon; Lee, Sang Hoon; Yoo, Kwang Hoon

2004-01-01

Soil properties supporting structure may become criteria determining methodologies for seismic response analysis of a structure. Regulatory Guide describes that a fixed-base assumption is acceptable for structures supported on rock or rock-like materials defined by a shear wave velocity of 3,500 ft/sec or greater at a shear strain of 10 -3 percent or smaller when considering preloaded soil conditions due to the structure. Seismic analyses for the Korean nuclear power plant (NPP) structures satisfying the above site soil condition have been completed through the fixed-base analysis. However, dynamic responses for relatively stiff structures such as NPP structures still have soil-structure interaction (SSI) effects. In other words, the fixed-base analysis does not always yield conservative results to be compared with SSI analysis. The SSI effects due to different stiff soil properties for Turbine Generator Building (TGB) structure to be constructed at Kori site of South Korea are investigated in views of floor response spectra (FRS) and member forces

A triple-scale crystal plasticity modeling and simulation on size effect due to fine-graining

International Nuclear Information System (INIS)

Kurosawa, Eisuke; Aoyagi, Yoshiteru; Tadano, Yuichi; Shizawa, Kazuyuki

2010-01-01

In this paper, a triple-scale crystal plasticity model bridging three hierarchical material structures, i.e., dislocation structure, grain aggregate and practical macroscopic structure is developed. Geometrically necessary (GN) dislocation density and GN incompatibility are employed so as to describe isolated dislocations and dislocation pairs in a grain, respectively. Then the homogenization method is introduced into the GN dislocation-crystal plasticity model for derivation of the governing equation of macroscopic structure with the mathematical and physical consistencies. Using the present model, a triple-scale FE simulation bridging the above three hierarchical structures is carried out for f.c.c. polycrystals with different mean grain size. It is shown that the present model can qualitatively reproduce size effects of macroscopic specimen with ultrafine-grain, i.e., the increase of initial yield stress, the decrease of hardening ratio after reaching tensile strength and the reduction of tensile ductility with decrease of its grain size. Moreover, the relationship between macroscopic yielding of specimen and microscopic grain yielding is discussed and the mechanism of the poor tensile ductility due to fine-graining is clarified. (author)

Uncertainty in soil-structure interaction analysis of a nuclear power plant due to different analytical techniques

International Nuclear Information System (INIS)

Chen, J.C.; Chun, R.C.; Goudreau, G.L.; Maslenikov, O.R.; Johnson, J.J.

1984-01-01

This paper summarizes the results of the dynamic response analysis of the Zion reactor containment building using three different soil-structure interaction (SSI) analytical procedures: the substructure method, CLASSI; the equivalent linear finite element approach, ALUSH and the nonlinear finite element procedure, DYNA3D. Uncertainties in analyzing a soil-structure system due to SSI analysis procedures were investigated. Responses at selected locations in the structure were compared: peak accelerations and response spectra

Structural changes of small amplitude kinetic Alfvén solitary waves due to second-order corrections

International Nuclear Information System (INIS)

Choi, Cheong R.

2015-01-01

The structural changes of kinetic Alfvén solitary waves (KASWs) due to higher-order terms are investigated. While the first-order differential equation for KASWs provides the dispersion relation for kinetic Alfvén waves, the second-order differential equation describes the structural changes of the solitary waves due to higher-order nonlinearity. The reductive perturbation method is used to obtain the second-order and third-order partial differential equations; then, Kodama and Taniuti's technique [J. Phys. Soc. Jpn. 45, 298 (1978)] is applied in order to remove the secularities in the third-order differential equations and derive a linear second-order inhomogeneous differential equation. The solution to this new second-order equation indicates that, as the amplitude increases, the hump-type Korteweg-de Vries solution is concentrated more around the center position of the soliton and that dip-type structures form near the two edges of the soliton. This result has a close relationship with the interpretation of the complex KASW structures observed in space with satellites

The evolution of magnetic structures due to open-quote open-quote magnetosonic streaming close-quote close-quote

International Nuclear Information System (INIS)

Ryutova, M.P.; Kaisig, M.; Tajima, T.

1996-01-01

The Faraday effect in gasdynamics called acoustic streaming and its accompanying nonlinear phenomena have analogies in plasma magnetohydrodynamics. A natural place where these effects may occur is the solar atmosphere with its strongly inhomogeneous magnetic fields concentrated in random magnetic flux tubes. Unlike acoustic streaming in the usual gasdynamics, nonlinear phenomena consisting in the generation of plasma flows by an oscillating magnetic flux tube, open-quote open-quote magnetosonic streaming close-quote close-quote (Ryutova 1986), is accompanied by a current drive and results in a specific evolution of magnetic structures: depending on the physical parameters of the medium a single magnetic flux tube may be either split into thinner flux tubes or dissolved diffusively into the ambient plasma. The effect of the open-quote open-quote magnetosonic streaming,close-quote close-quote on one hand, is an obvious candidate for the generation of mass flows at magnetic flux tubes sites, and on the other hand, it plays an essential role in the evolution of magnetic structures and ultimately may determine their lifetime. The theory of magnetosonic streaming is general and can be applied to other astrophysical objects that maintain oscillatory motions and contain structured magnetic fields or magnetic domains. We review analytical results and describe the origin of the magnetosonic streaming in magnetic flux tubes due to their interaction with acoustic waves. We study numerically the regime of the open-quote open-quote magnetosonic streaming close-quote close-quote corresponding to splitting of a magnetic flux tube. Our computer simulation supports and extends the analytical result. copyright 1996 The American Astronomical Society

Fluid transport due to nonlinear fluid-structure interaction

DEFF Research Database (Denmark)

Jensen, Jakob Søndergaard

1997-01-01

This work considers nonlinear fluid-structure interaction for a vibrating pipe containing fluid. Transverse pipe vibrations will force the fluid to move relative to the pipe creating unidirectional fluid flow towards the pipe end. The fluid flow induced affects the damping and the stiffness...... of the pipe. The behavior of the system in response to lateral resonant base excitation is analysed numerically and by the use of a perturbation method (multiple scales). Exciting the pipe in the fundamental mode of vibration seems to be most effective for transferring energy from the shaker to the fluid......, whereas higher modes of vibration can be used to transport fluid with pipe vibrations of smaller amplitude. The effect of the nonlinear geometrical terms is analysed and these terms are shown to affect the response for higher modes of vibration. Experimental investigations show good agreement...

Assessment of soil-structure interaction effects based on simple modes

International Nuclear Information System (INIS)

Philippacopoulos, A.J.; Miller, C.A.

1983-01-01

Soil-structure interaction effects are investigated using a simple mathematical model which employs three degrees-of-freedom. The foundation is approximated by a homogeneous, isotropic, elastic half-space. Harmonic functions and a recorded earthquake are used to represent the free-field input motion. Variations of the response characteristics due to structural and interaction parameters are demonstrated. Response spectra are presented that display the magnitude of the maximum structural response for a range of fixed-base structural frequencies, interaction frequencies and damping. Conclusions are obtained regarding the behavior of the response of the soil-structure system. The findings reported herein can be used for the interpretation of the results of soil-structure interaction analyses of nuclear plant structures that are performed with available computer codes

Effect of superconductivity on the cubic to tetragonal structural transition due to a two-fold degenerate electronic band

International Nuclear Information System (INIS)

Ghatak, S.K.; Khanra, B.C.; Ray, D.K.

1978-01-01

The effect of the BCS superconductivity on the cubic to tetragonal structural transition arising from a two-fold degenerate electronic band is investigated within the mean field approximation. The phase diagram of the two transitions is given for a half filled esub(g)-band. Modification of the two transitions when they are close together is also discussed. (author)

Electronic, structural, and substrate effect properties of single-layer covalent organic frameworks

International Nuclear Information System (INIS)

Liang, Liangbo; Zhu, Pan; Meunier, Vincent

2015-01-01

Recently synthesized two-dimensional covalent organic frameworks (COFs) exhibit high surface area, large pore size, and unique structural architectures, making them promising materials for various energy applications. Here, a total of nine COFs structures, including two deposited on a hexagonal boron nitride substrate, are investigated using density functional theory, quasi-particle many-body theory within the GW approximation, and an image charge model. The structures considered belong to two major families (thiophene-based COF-n (T-COF-n) and tetrakis (4-aminophenyl) porphyrin-x (TAPP-x)) differing from the presence of B—O or C=N linkers. While T-COF-n structures are shown to constitute planar networks, TAPP-x systems can display non-negligible corrugation due to the out-of-plane rotation of phenyl rings. We find that the electronic properties do not differ significantly when altering the chain molecules within each family. Many-body effects are shown to lead to large band-gap increase while the presence of the substrate yields appreciable reductions of the gaps, due to substrate polarization effects

Density Effects on Post-shock Turbulence Structure

Science.gov (United States)

Tian, Yifeng; Jaberi, Farhad; Livescu, Daniel; Li, Zhaorui; Michigan State University Collaboration; Los Alamos National Laboratory Collaboration; Texas A&M University-Corpus Christi Collaboration

2017-11-01

The effects of density variations due to mixture composition on post-shock turbulence structure are studied using turbulence-resolving shock-capturing simulations. This work extends the canonical Shock-Turbulence Interaction (STI) problem to involve significant variable density effects. The numerical method has been verified using a series of grid and LIA convergence tests, and is used to generate accurate post-shock turbulence data for a detailed flow study. Density effects on post-shock turbulent statistics are shown to be significant, leading to an increased amplification of turbulent kinetic energy (TKE). Eulerian and Lagrangian analyses show that the increase in the post-shock correlation between rotation and strain is weakened in the case with significant density variations (referred to as the ``multi-fluid'' case). Similar to previous single-fluid results and LIA predictions, the shock wave significantly changes the topology of the turbulent structures, exhibiting a symmetrization of the joint PDF of second and third invariant of the deviatoric part of velocity gradient tensor. In the multi-fluid case, this trend is more significant and mainly manifested in the heavy fluid regions. Lagrangian data are also used to study the evolution of turbulence structure away from the shock wave and assess the accuracy of Lagrangian dynamical models.

Increase in electron mobility of InGaAs/InP composite channel high electron mobility transistor structure due to SiN passivation

International Nuclear Information System (INIS)

Liu Yuwei; Wang Hong; Radhakrishnan, K.

2007-01-01

The influence of silicon nitride passivation on electron mobility of InGaAs/InP composite channel high electron mobility transistor structure has been studied. Different from the structures with single InGaAs channel, an increase in effective mobility μ e with a negligible change of sheet carrier density n s after SiN deposition is clearly observed in the composite channel structures. The enhancement of μ e could be explained under the framework of electrons transferring from the InP sub-channel into InGaAs channel region due to the energy band bending at the surface region caused by SiN passivation, which is further confirmed by low temperature photoluminescence measurements

Plasmon mediated inverse Faraday effect in a graphene-dielectric-metal structure.

Science.gov (United States)

Bychkov, Igor V; Kuzmin, Dmitry A; Tolkachev, Valentine A; Plaksin, Pavel S; Shavrov, Vladimir G

2018-01-01

This Letter shows the features of inverse Faraday effect (IFE) in a graphene-dielectric-metal (GDM) structure. The constants of propagation and attenuation of the surface plasmon-polariton modes are calculated. The effective magnetic field induced by surface plasmon modes in the dielectric due to the IFE is estimated to reach above 1 tesla. The possibility to control the distribution of the magnetic field by chemical potential of graphene is shown. The concept of strain-driven control of the IFE in the structure has been proposed and investigated.

Investigations of surface-tension effects due to small-scale complex boundaries

Science.gov (United States)

Feng, Jiansheng

In this Ph.D. dissertation, we have investigated some important surface-tension phenomena including capillarity, wetting, and wicking. We mainly focus on the geometric aspects of these problems, and to learn about how structures affect properties. . In the first project (Chapter 2), we used numerical simulations and experiments to study the meniscus of a fluid confined in capillaries with complicated cross-sectional geometries. In the simulations, we computed the three-dimensional shapes of the menisci formed in polygonal and star-shaped capillaries with sharp or rounded corners. Height variations across the menisci were used to quantify the effect of surface tension. Analytical solutions were derived for all the cases where the cross-sectional geometry was a regular polygon or a regular star-shape. Power indices that characterize the effects of corner rounding were extracted from simulation results. These findings can serve as guide for fabrications of unconventional three-dimensional structures in Capillary Force Lithography experiments. Experimental demonstrations of the working principle was also performed. Although quantitative matching between simulation and experimental results was not achieved due to the limitation of material properties, clear qualitative trends were observed and interesting three-dimensional nano-structures were produced. A second project (Chapter 3) focused on developing techniques to produce three-dimensional hierarchically structured superhydrophobic surfaces with high aspect ratios. We experimented with two different high-throughput electron-beam-lithography processes featuring single and dual electron-beam exposures. After a surface modification procedure with a hydrophobic silane, the structured surfaces exhibited two distinct superhydrophobic behaviors---high and low adhesion. While both types of superhydrophobic surfaces exhibited very high (approximately 160° water advancing contact angles, the water receding contact angles on

Renormalization of effective mass in self-assembled quantum dots due to electron-electron interactions

International Nuclear Information System (INIS)

Babinski, A; Korkusinski, M; Hawrylak, P; Wasilewski, Z R; Potemski, M

2013-01-01

Magnetic-field dispersion of the multiexcitons related to the p shell of a single quantum dot (QD) is analysed in this work. The reduced cyclotron effective mass of carriers is determined from the energy splitting between the p + - and p − - related multiexcitonic emission lines. The reduced mass in the occupied QD was found to be larger than the mass related to the QD's single particle structure. The apparent increase of the reduced mass with increasing excitonic occupation of the dot is related to the mass renoralization due to electron-electron interactions within a multiexcitonic droplet

Considering soil-structure interaction effects in the equivalent static analysis method of the Iranian of the Iranian seismic building code

International Nuclear Information System (INIS)

Shakib, H.; Dehghani Ashkezari, G.

2002-01-01

In this study, based on the equivalent static analysis method of the Iranian seismic code, an algorithm is presented to consider the soil-structure interaction (SSI) effects. Modifications of free field motion and structural properties like period and damping due to soil situation are considered in the proposed algorithm. An increase for fundamental period of structure and a modification (usually increase) for it's effective damping are observed. The increase of period is due to the flexibility of the soil foundation and modification of damping is due to the dissipating energy in soil. In order to propose the relative expressions in the presented algorithm, the soil-structure analyses of 8, 10, 13 and 16 stories frames are carried out. By considering the NEHRP soil-structure interaction algorithm and findings of soil-structure interaction analyses carried out in this study, the algorithm based on the equivalent static analysis method of the Iranian seismic building code to consider the effect of soil-structure interaction

Sloshing, fluid-structure interaction and structural response due to shock and impact loads 1994. PVP-Vol. 272

International Nuclear Information System (INIS)

Ma, D.C.; Shin, Y.S.; Brochard, D.; Fujita, K.

1994-01-01

This volume is comprised of papers presented in two symposia at the 1994 ASME Pressure Vessels and Piping Conference. These sessions, sponsored by the Fluid-Structure Interaction and Seismic Engineering Technical Committees, provided a forum for the discussion of recent advances in sloshing, fluid-structure interaction, and structural dynamics produced by high energy excitations. The papers presented at the four technical sessions on Sloshing and Fluid-Structure Interaction represent a broad spectrum of fluid-structure systems: sloshing, fluid-structure interaction, and dynamic and seismic response of various fluid-structure systems such as reactor components, liquid storage tanks, submerged structures and piping systems, etc. The paper presented at the session on Structural Dynamics Produced by High-Energy Excitations cover underwater explosion effects on submerged structures, bubble loading phenomena, finite element mesh refinements on failure predictions, penetration and impact problems, and dynamic design of blast containment vessels. Also included are numerical analysis, design, and testing to understand difficult transient response phenomena. Separate abstracts were prepared for 24 papers in this volume

Effects of radiation on MOS structures and silicon devices

International Nuclear Information System (INIS)

Braeunig, D.; Fahrner, W.

1983-02-01

A comprehensive view of radiation effects on MOS structures and silicon devices is given. In the introduction, the interaction of radiation with semiconductor material is presented. In the next section, the electrical degradation of semiconductor devices due to this interaction is discussed. The commonly used hardening techniques are shown. The last section deals with testing of radiation hardness of devices. (orig.) [de

Interpretation of interfacial structures in X-ray multilayers by TEM Fresnel fringe effects

OpenAIRE

Nguyen, Tai D.; O'Keefe, Michael A.; Kilaas, Roar; Gronsky, Ronald; Kortright, Jeffrey B.

1991-01-01

Assessment of interfacial structures from high-resolution TEM images of cross-sectional specimens is difficult due to Fresnel fringe effects producing different apparent structures in the images. The effects of these fringes have been commonly over-looked in efforts of making quantitative interpretation of interfacial profiles. In this report, we present the observations of the Fresnel fringes in nanometer period Mo/Si, W/C, and WC/C multilayers in through-focus-series TEM images. Calculation...

Effect of foundation flexibility on the vibrational stability of the National Ignition Facility optical system support structures

International Nuclear Information System (INIS)

McCallen, D.

1997-01-01

Alignment requirements for the National Ignition Facility (NIF) optical components will require a number of support structures which minimize the system displacements and deformations. The stringent design requirements for this facility will result in a system in which vibrations due to ambient environmental loads (e.g. foundation motion due to typical traffic loads, microseisms or nearby equipment) will have a significant, and perhaps predominant, influence on the design of the supporting structures. When considering the total deformations and displacements of the structural systems, the contribution of the foundation to the overall system flexibility must be addressed. Classical fixed-base structural analyses, which are predicated on an assumption of an infinitely rigid foundation system, neglect the influence of foundation flexibility and for the vibration regime in which the NIF structures reside, may result in significant underestimation of the system ambient vibration displacements. In the work described herein, parametric studies were performed in order to understand the potential contributions of soil-structure- interaction (SSI) to optical system displacements. Time domain finite element analyses were employed to quantify the effect of wave scattering by the mat foundation and the effects of inertial SSI due to the rocking of the massive shear wall support structures. A simplified procedure is recommended for accounting for SSI effects in the design of the special equipment structures. The simplified approach consists of applying a scale factor to displacements obtained from fixed base analyses to approximately account for the effects of soil-structure interaction and variable support input motion

Reinforced concrete bridges: effects due to corrosion and concrete young modulus variation

Directory of Open Access Journals (Sweden)

P. T. C. Mendes

Full Text Available Most of the Brazilian bridges of federal road network are made of reinforced concrete and are more than 30 years old, with little information about the mechanical properties of their constitutive materials. Along the service life of these bridges much modification occurred on vehicles load and geometry and in design standard. Many of them show signs of concrete and steel deterioration and their stability conditions are unknown. With the aim of contributing to the structural evaluation of reinforced concrete bridges it was decided to analyze the stresses in reinforced concrete bridge sections to verify the effects due to reinforcement corrosion and variation of the concrete Young modulus on the stress distribution regarding several load patterns and cracking effects in a representative bridge of the Brazilian road network with different longitudinal reinforcement taxes and two concrete Young modulus, Ec and 0.5Ec, and with different percentage of reinforcement corrosion. The analysis considered two finite element models: frame and shell elements as well as solid elements. The results indicate that these variation effects are more significant in reinforcement bars than in concrete.

Effect of Iron and Magnesium on Alloy AL9M Structure and Properties

Science.gov (United States)

Bazhenov, V. E.; Koltygin, A. V.; Belov, V. D.

2017-09-01

The effect of iron impurity on the structure and properties of aluminum alloy AL9M, especially its action on magnesium distribution within the structure, is studied. The microstructure of a cast component of this alloy broken during operation is analyzed. It is shown that iron impurity has an unfavorable effect on structure and mechanical properties of a casting due to appearance of Al9Fe2Si and Al18Fe2Mg7Si10 intermetallics. Formation of these intermetallics consumes a considerable amount of magnesium and lowers the content of the Q(Al5Cu2Mg8Si6) strengthening phase in the alloy structure.

Investigating structural and perfusion deficits due to repeated head trauma in active professional fighters.

Science.gov (United States)

Mishra, Virendra; Sreenivasan, Karthik; Banks, Sarah J; Zhuang, Xiaowei; Yang, Zhengshi; Cordes, Dietmar; Bernick, Charles

2018-01-01

Repeated head trauma experienced by active professional fighters results in various structural, functional and perfusion damage. However, whether there are common regions of structural and perfusion damage due to fighting and whether these structural and perfusion differences are associated with neuropsychological measurements in active professional fighters is still unknown. To that end, T1-weighted and pseudocontinuous arterial spin labeling MRI on a group of healthy controls and active professional fighters were acquired. Voxelwise group comparisons, in a univariate and multivariate sense, were performed to investigate differences in gray and white matter density (GMD, WMD) and cerebral blood flow (CBF) between the two groups. A significantly positive association between global GMD and WMD was obtained with psychomotor speed and reaction time, respectively, in our cohort of active professional fighters. In addition, regional WMD deficit was observed in a cluster encompassing bilateral pons, hippocampus, and thalamus in fighters (0.49 ± 0.04 arbitrary units (a.u.)) as compared to controls (0.51 ± 0.05a.u.). WMD in the cluster of active fighters was also significantly associated with reaction time. Significantly lower CBF was observed in right inferior temporal lobe with both partial volume corrected (46.9 ± 14.93 ml/100 g/min) and non-partial volume corrected CBF maps (25.91 ± 7.99 ml/100 g/min) in professional fighters, as compared to controls (65.45 ± 22.24 ml/100 g/min and 35.22 ± 12.18 ml/100 g/min respectively). A paradoxical increase in CBF accompanying right cerebellum and fusiform gyrus in the active professional fighters (29.52 ± 13.03 ml/100 g/min) as compared to controls (19.43 ± 12.56 ml/100 g/min) was observed with non-partial volume corrected CBF maps. Multivariate analysis with both structural and perfusion measurements found the same clusters as univariate analysis in addition to a cluster in right precuneus

Investigating structural and perfusion deficits due to repeated head trauma in active professional fighters

Directory of Open Access Journals (Sweden)

Virendra Mishra

2018-01-01

Full Text Available Repeated head trauma experienced by active professional fighters results in various structural, functional and perfusion damage. However, whether there are common regions of structural and perfusion damage due to fighting and whether these structural and perfusion differences are associated with neuropsychological measurements in active professional fighters is still unknown. To that end, T1-weighted and pseudocontinuous arterial spin labeling MRI on a group of healthy controls and active professional fighters were acquired. Voxelwise group comparisons, in a univariate and multivariate sense, were performed to investigate differences in gray and white matter density (GMD, WMD and cerebral blood flow (CBF between the two groups. A significantly positive association between global GMD and WMD was obtained with psychomotor speed and reaction time, respectively, in our cohort of active professional fighters. In addition, regional WMD deficit was observed in a cluster encompassing bilateral pons, hippocampus, and thalamus in fighters (0.49 ± 0.04 arbitrary units (a.u. as compared to controls (0.51 ± 0.05a.u.. WMD in the cluster of active fighters was also significantly associated with reaction time. Significantly lower CBF was observed in right inferior temporal lobe with both partial volume corrected (46.9 ± 14.93 ml/100 g/min and non-partial volume corrected CBF maps (25.91 ± 7.99 ml/100 g/min in professional fighters, as compared to controls (65.45 ± 22.24 ml/100 g/min and 35.22 ± 12.18 ml/100 g/min respectively. A paradoxical increase in CBF accompanying right cerebellum and fusiform gyrus in the active professional fighters (29.52 ± 13.03 ml/100 g/min as compared to controls (19.43 ± 12.56 ml/100 g/min was observed with non-partial volume corrected CBF maps. Multivariate analysis with both structural and perfusion measurements found the same clusters as univariate analysis in addition to a cluster in right

'Vanishing' structural effects of temperature in polymer glasses close to the glass-transition temperature

International Nuclear Information System (INIS)

Shantarovich, V.P.; Suzuki, T.; Ito, Y.; Yu, R.S.; Kondo, K.; Yampolskii, Yu. P.; Alentiev, A.Yu.

2007-01-01

Positron annihilation lifetime (PAL) measurements were used for observation of structural effects of temperature in polystyrene (PS), super-cross-linked polystyrene networks (CPS), and in polyimides (PI) below and in the vicinity of glass-transition temperature T g . 'Vanishing' of these structural effects in the repeating cycles of the temperature controlled PAL experiments due to the slow relaxation processes in different conditions and details of chemical structure is demonstrated. Obtained results illustrate complex, dependent on thermal history, inhomogeneous character of the glass structure. In fact, structure of some polymer glasses is changing continuously. Calculations of the number density of free volume holes in these conditions are discussed

Field tests on partial embedment effects (embedment effect tests on soil-structure interaction)

International Nuclear Information System (INIS)

Kurimoto, O.; Tsunoda, T.; Inoue, T.; Izumi, M.; Kusakabe, K.; Akino, K.

1993-01-01

A series of Model Tests of Embedment Effect on Reactor Buildings has been carried out by the Nuclear Power Engineering Corporation (NUPEC), under the sponsorship of the Ministry of International Trade and lndustry (MITI) of Japan. The nuclear reactor buildings are partially embedded due to conditions for the construction or building arrangement in Japan. It is necessary to verify the partial embedment effects by experiments and analytical studies in order to incorporate the effects in the seismic design. Forced vibration tests, therefore, were performed using a model with several types of embedment. Correlated simulation analyses were also performed and the characteristics of partial embedment effects on soil-structure interaction were evaluated. (author)

Structure-activity relationship of immunostimulatory effects of phthalates

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Nielsen Gunnar D

2008-10-01

Full Text Available Abstract Background Some chemicals, including some phthalate plasticizers, have been shown to have an adjuvant effect in mice. However, an adjuvant effect, defined as an inherent ability to stimulate the humoral immune response, was only observed after exposure to a limited number of the phthalates. An adjuvant effect may be due to the structure or physicochemical characteristics of the molecule. The scope of this study was to investigate which molecular characteristics that determine the observed adjuvant effect of the most widely used phthalate plasticizer, the di-(2-ethylhexyl phthalate (DEHP, which is documented as having a strong adjuvant effect. To do so, a series of nine lipophilic compounds with structural and physicochemical relations to DEHP were investigated. Results Adjuvant effect of phthalates and related compounds were restricted to the IgG1 antibody formation. No effect was seen on IgE. It appears that lipophilicity plays a crucial role, but lipophilicity does not per se cause an adjuvant effect. In addition to lipophilicity, a phthalate must also possess specific stereochemical characteristics in order for it to have adjuvant effect. Conclusion The adjuvant effect of phthalates are highly influenced by both stereochemical and physico-chemical properties. This knowledge may be used in the rational development of plasticizers without adjuvant effect as well as in the design of new immunological adjuvants.

Formation of the self-assembled structures by the ultrasonic cavitation erosion-corrosion effect on carbon steel

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Dayun Yan

2015-11-01

Full Text Available The cavitation erosion-corrosion effect on the metal surface always forms irregular oxide structures. In this study, we reported the formation of regular self-assembled structures of amorphous nanoparticles around the cavitation erosion pits on carbon steel upon the ultrasonic cavitation in methylene blue solution. Each self-assembled structure was composed of linearly aligned nanoparticles of about 100 nm. The formation of self-assembled structures might be due to the combined effect of corrosion, specific sonochemical reaction in methylene blue solution, and the magnetic domain structures on the carbon steel.

Emissions embodied in global trade have plateaued due to structural changes in China

Science.gov (United States)

Pan, Chen; Peters, Glen P.; Andrew, Robbie M.; Korsbakken, Jan Ivar; Li, Shantong; Zhou, Dequn; Zhou, Peng

2017-09-01

In the 2000s, the rapid growth of CO2 emitted in the production of exports from developing to developed countries, in which China accounted for the dominant share, led to concerns that climate polices had been undermined by international trade. Arguments on "carbon leakage" and "competitiveness"—which led to the refusal of the U.S. to ratify the Kyoto Protocol—put pressure on developing countries, especially China, to limit their emissions with Border Carbon Adjustments used as one threat. After strong growth in the early 2000s, emissions exported from developing to developed countries plateaued and could have even decreased since 2007. These changes were mainly due to China: In 2002-2007, China's exported emissions grew by 827 MtCO2, amounting to almost all the 892 MtCO2 total increase in emissions exported from developing to developed countries, while in 2007-2012, emissions exported from China decreased by 229 MtCO2, contributing to the total decrease of 172 MtCO2 exported from developing to developed countries. We apply Structural Decomposition Analysis to find that, in addition to the diminishing effects of the global financial crisis, the slowdown and eventual plateau was largely explained by several potentially permanent changes in China: Decline in export volume growth, improvements in CO2 intensity, and changes in production structure and the mix of exported products. We argue that growth in China's exported emissions will not return to the high levels during the 2000s, therefore the arguments for climate polices focused on embodied emissions such as Border Carbon Adjustments are now weakened.

Watershed evapotranspiration increased due to changes in vegetation composition and structure under a subtropical climate

Science.gov (United States)

Ge Sun; Changqing Zuo; Shiyu Liu; Mingliang Liu; Steven G McNulty; James M. Vose

2008-01-01

Natural forests in southern China have been severely logged due to high human demand for timber, food, and fuels during the past century, but are recovering in the past decade. The objective of this study was to investigate how vegetation cover changes in composition and structure affected the water budgets of a 9.6-km2 Dakeng watershed located...

Evaluation of blast-induced vibration effects on structures 1

Energy Technology Data Exchange (ETDEWEB)

Lee, Jong Rim; Jeon, Gyu Shick; Lee, Dae Soo; Joo, Kwang Ho; Lee, Woong Keon [Korea Electrotechnology Research Inst., Changwon (Korea, Republic of); Ryu, Chang Ha; Chung, So Keul; Lee, Kyung Won; Shin, Hee Soon; Chun, Sun Woo; Park, Yeon Jun; Synn, Joong Ho; Choi, Byung Hee [Korea Inst. of Geology Mining and Materials, Taejon (Korea, Republic of)

1995-12-31

Due to the difficulties of obtaining construction site for new plants, following ones are inevitably being built in the site adjacent to existing power plants. Therefore considerable thought has been recently given to the dynamic loading generated by blasting works near the plants to maintain the safety of structures and facilities in power plants. Our own standard for safety level of blast vibration is not prepared yet, and foreign standards have been generally employed without theoretical and experimental verification. Safety-related structures of power plants and facilities have to be protected against the effects of possible hazards due to blast vibration. Earthquakes have been considered a major dynamic design loading as a requirement of plant design, but the effects of blast-induced vibration are not. In order to ensure the safety, rational safe criterion should be established and blast design should be satisfy it, which requires the development of a model for prediction of vibration level through more systematic measurement and analysis. The main objectives of the study are : to provide background data for establishing the rational safe vibration limits, to develop models for prediction of blast vibration level, to establish safe blast design criterion, and to accumulate techniques for field measurements, data acquisition and analysis (author). 80 refs., 347 figs.

Experimental Verification Of Secondary Effect Due To Prestressing

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Pažma Peter

2015-12-01

Full Text Available The aim of this article is to describe an experimental program at Slovak University of Technology in Bratislava, Department of concrete structures and bridges and its results. This experimental program was focused on two main subjects. The first one, which is also the topic of this article was an analysis of prestressing effects on the statically indeterminate structures, where the redundancy had been changed up to the kinematic mechanism development. The second topic was an analysis of behaviour of the prestressing units with different bond.

Structural mechanisms of the flux effect for VVER-1000 reactor pressure vessel materials

International Nuclear Information System (INIS)

Gurovich, B.; Kuleshova, E.; Fedotova, S.; Maltsev, D.; Zabusov, O.; Frolov, A.; Erak, D.; Zhurko, D.

2015-01-01

To justify the lifetime extension of VVER-1000 reactor pressure vessels (RPV) up to 60 years and more it is necessary to expand the existing surveillance samples database to beyond design fluence by means of accelerated irradiation in a research reactor. Herewith since the changes in mechanical properties of materials under irradiation are due to occurring structural changes, correct analysis of the data obtained at accelerated irradiation of VVER-1000 RPV materials requires a clear understanding of the structural mechanisms that are responsible for the flux effect in VVER-1000 RPV steels. Two mechanisms are responsible for radiation embrittlement of VVER-1000 RPV steels: the hardening one (radiation hardening due to formation of radiation-induced Ni-based precipitates and radiation defects) and non-hardening one (due to formation of impurities segregations at grain boundaries - reversible temper brittleness). In this context for an adequate interpretation of the mechanical tests results when justifying the lifetime extension of existing units a complex of comparative structural studies (TEM, SEM and AES) of VVER-1000 RPV materials irradiated in different conditions (in research reactor IR-8 and within surveillance samples) was performed. It is shown that the flux effect is observed for materials with high nickel content (weld metals with Ni content > 1.35%) and it is mostly due to the contribution of non-hardening mechanism of radiation embrittlement (the difference in the accumulation kinetics of grain boundary phosphorus segregation) and somewhat contribution of the hardening mechanism (the difference in density of radiation-induced precipitates). Therefore when analyzing the results obtained from the accelerated irradiation of VVER-1000 WM the correction for the flux effect should be made. (authors)

Application of PCR-denaturing-gradient gel electrophoresis (DGGE) method to examine microbial community structure in asparagus fields with growth inhibition due to continuous cropping.

Science.gov (United States)

Urashima, Yasufumi; Sonoda, Takahiro; Fujita, Yuko; Uragami, Atsuko

2012-01-01

Growth inhibition due to continuous cropping of asparagus is a major problem; the yield of asparagus in replanted fields is low compared to that in new fields, and missing plants occur among young seedlings. Although soil-borne disease and allelochemicals are considered to be involved in this effect, this is still controversial. We aimed to develop a technique for the biological field diagnosis of growth inhibition due to continuous cropping. Therefore, in this study, fungal community structure and Fusarium community structure in continuously cropped fields of asparagus were analyzed by polymerase chain reaction/denaturing-gradient gel electrophoresis (PCR-DGGE). Soil samples were collected from the Aizu region of Fukushima Prefecture, Japan. Soil samples were taken from both continuously cropped fields of asparagus with growth inhibition and healthy neighboring fields of asparagus. The soil samples were collected from the fields of 5 sets in 2008 and 4 sets in 2009. We were able to distinguish between pathogenic and non-pathogenic Fusarium by using Alfie1 and Alfie2GC as the second PCR primers and PCR-DGGE. Fungal community structure was not greatly involved in the growth inhibition of asparagus due to continuous cropping. By contrast, the band ratios of Fusarium oxysporum f. sp. asparagi in growth-inhibited fields were higher than those in neighboring healthy fields. In addition, there was a positive correlation between the band ratios of Fusarium oxysporum f. sp. asparagi and the ratios of missing asparagus plants. We showed the potential of biological field diagnosis of growth inhibition due to continuous cropping of asparagus using PCR-DGGE.

Secondary Moments due to Prestressing with Different Bond at the Ultimate Limit State

Directory of Open Access Journals (Sweden)

Halvoník Jaroslav

2018-03-01

Full Text Available Secondary effects of prestressing develop in statically indeterminate structures (e.g., continuous beams due to the restraint of deformations imposed by hyperstatic restraints. These effects may significantly influence internal forces and stresses in prestressed structures. Secondary effects are influenced by the redundancy of a structural system, which raises the question of whether they will remain constant after a change in the structural system, e.g., due to the development of plastic hinge(s in a critical cross-section(s or after the development of a kinematic mechanism, or if they will disappear when the structure changes into a sequence of simply supported beams. The paper deals with an investigation of the behavior of continuous post-tensioned beams subjected to an ultimate load with significant secondary effects from prestressing. A total of 6 two-span beams prestressed by tendons with different bonds were tested in a laboratory with a load that changed their structural system into a kinematic mechanism. The internal forces and secondary effects of the prestressing were controlled through measurements of the reactions in all the supports. The results revealed that the secondary effects remained as a permanent part of the action on the experimental beams, even after the development of the kinematic mechanism. The results obtained confirmed that secondary effects should be included in all combinations of actions for verifications of ultimate limit states (ULS.

Secondary Moments due to Prestressing with Different Bond at the Ultimate Limit State

Science.gov (United States)

Halvoník, Jaroslav; Pažma, Peter; Vida, Radoslav

2018-03-01

Secondary effects of prestressing develop in statically indeterminate structures (e.g., continuous beams) due to the restraint of deformations imposed by hyperstatic restraints. These effects may significantly influence internal forces and stresses in prestressed structures. Secondary effects are influenced by the redundancy of a structural system, which raises the question of whether they will remain constant after a change in the structural system, e.g., due to the development of plastic hinge(s) in a critical cross-section(s) or after the development of a kinematic mechanism, or if they will disappear when the structure changes into a sequence of simply supported beams. The paper deals with an investigation of the behavior of continuous post-tensioned beams subjected to an ultimate load with significant secondary effects from prestressing. A total of 6 two-span beams prestressed by tendons with different bonds were tested in a laboratory with a load that changed their structural system into a kinematic mechanism. The internal forces and secondary effects of the prestressing were controlled through measurements of the reactions in all the supports. The results revealed that the secondary effects remained as a permanent part of the action on the experimental beams, even after the development of the kinematic mechanism. The results obtained confirmed that secondary effects should be included in all combinations of actions for verifications of ultimate limit states (ULS).

Biofilm Effect on Flow Structure over a Permeable Bed

Science.gov (United States)

Kazemifar, F.; Blois, G.; Aybar, M.; Perez-Calleja, P.; Nerenberg, R.; Sinha, S.; Hardy, R. J.; Best, J.; Sambrook Smith, G.; Christensen, K. T.

2017-12-01

Biofilms constitute an important form of bacterial life in aquatic environments and are present at the fluid-solid interfaces in natural and industrial settings, such as water distribution systems and riverbeds among others. The permeable, heterogeneous, and deformable structure of biofilms can influence mass and momentum transport between the subsurface and freestream. However, this interaction is not fully understood, in part due to technical obstacles impeding quantitative experimental investigations. In this work, the effect of biofilm on flow structure over a permeable bed is studied. Experiments are conducted in a closed water channel equipped with an idealized two-dimensional permeable bed. Prior to conducting flow experiments, the models are placed within an independent recirculating reactor for biofilm growth. Once a targeted biofilm growth stage is achieved, the models are transferred to the water channel and subjected to transitional and turbulent flows. Long-distance microscopic particle image velocimetry measurements are performed to quantify the effect of biofilm on the turbulence structure of the free flow as well as the freestream-subsurface flow interaction.

THE STUDY ON THE DURABILITY OF SUBMERGED STRUCTURE DISPLACEMENT DUE TO CONCRETE FAILURE

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M. Mohd

2016-09-01

Full Text Available Concrete structures that exposed to marine environments are subjected to multiple deterioration mechanisms. An overview of the existing technology for submerged concrete, pressure resistant, concrete structures which related such as cracks, debonds, and delamination are discussed. Basic knowledge related to drowning durability such as submerged concrete structures in the maritime environment are the durability of a concrete and the ability to resist to weathering, chemical attack, abrasion or other deterioration processes. The measuring techniques and instrumentation for geometrical monitoring of submerged structural displacements have traditionally been categorized into two groups according to the two main groups, namely as geodetic surveying and geotechnical structural measurements of local displacements. This paper aims to study the durability of submerged concrete displacement and harmful effects of submerged concrete structures.

Numerical simulation of baseflow modification due to effects of ...

African Journals Online (AJOL)

Numerical simulation of baseflow modification due to effects of sediment yield. ... Physically-based mathematical modelling affords the opportunity to look at this kind of interaction, which should be simulated by deterministic responses of both water and fluvial processes. In addition to simulating the streamflow and ...

Analytical model for time to cover cracking in RC structures due to rebar corrosion

International Nuclear Information System (INIS)

Bhargava, Kapilesh; Ghosh, A.K.; Mori, Yasuhiro; Ramanujam, S.

2006-01-01

The structural degradation of concrete structures due to reinforcement corrosion is a major worldwide problem. Reinforcement corrosion causes a volume increase due to the oxidation of metallic iron, which is mainly responsible for exerting the expansive radial pressure at the steel-concrete interface and development of hoop tensile stresses in the surrounding concrete. Cracking occurs, once the maximum hoop tensile stress exceeds the tensile strength of the concrete. The cracking begins at the steel-concrete interface and propagates outwards and eventually results in the thorough cracking of the cover concrete and this would indicate the loss of service life for the corrosion affected structures. An analytical model is proposed to predict the time required for cover cracking and the weight loss of reinforcing bar in corrosion affected reinforced concrete structures. The modelling aspects of the residual strength of cracked concrete and the stiffness contribution from the combination of reinforcement and expansive corrosion products have also been incorporated in the model. The problem is modeled as a boundary value problem and the governing equations are expressed in terms of the radial displacement. The analytical solutions are presented considering a simple two-zone model for the cover concrete, viz. cracked or uncracked. Reasonable estimation of the various parameters in the model related to the composition and properties of expansive corrosion products based on the available published experimental data has also been discussed. The performance of the proposed corrosion cracking model is then investigated through its ability to reproduce available experimental trends. Reasonably good agreement between experimental results and the analytical predictions has been obtained. It has also been found that tensile strength and initial tangent modulus of cover concrete, annual mean corrosion rate and modulus of elasticity of reinforcement plus corrosion products combined

Differences in Femoral Geometry and Structure Due to Immobilization

Science.gov (United States)

Kiratli, Beatrice Jenny; Yamada, M.; Smith, A.; Marcus, R. M.; Arnaud, S.; vanderMeulen, M. C. H.; Hargens, Alan R. (Technical Monitor)

1996-01-01

Reduction in bone mass of the lower extremity is well documented in individuals with paralysis resulting from spinal cord injury (SCI). The consequent osteopenia leads to elevated fracture risk with fractures occurring more commonly in the femoral shaft and supracondylar regions than the hip. A model has recently been described to estimate geometry and structure of the femoral midshaft from whole body scans by dual X-ray absorptiometry (DXA). Increases in femoral geometric and structural properties during growth were primarily related to mechanical loading as reflected by body mass. In this study, we investigate the relationship between body mass and femoral geometry and structure in adults with normal habitual mechanical loading patterns and those with severely reduced loading. The subjects were 78 ambulatory men (aged 20-72 yrs) and 113 men with complete paralysis from SCI of more than 4 years duration (aged 21 73 yrs). Subregional analysis was performed on DXA whole body scans to obtain bone mineral content (BMC, g), cortical thickness (cm), crosssectional moment of inertia (CSMI, cm4), and section modulus (cm3) of the femoral midshaft. All measured bone variables were significantly lower in SCI compared with ambulatory subjects: -29% (BMC), -33% (cortical thickness), -23% (CSMI), and -22% (section modulus) while body mass was not significantly different. However, the associations between body mass and bone properties were notably different; r2 values were higher for ambulatory than SCI subjects in regressions of body mass on BMC (0.48 vs 0.20), CSMI (0.59 vs 0.32), and section modulus (0.59 vs 0.31). No association was seen between body mass and cortical thickness for either group. The greatest difference between groups is in the femoral cortex, consistent with reduced bone mass via endosteal expansion. The relatively lesser difference in geometric and structural properties implies that there is less effect on mechanical integrity than would be expected from

Lactate as an insidious metabolite due to the Warburg effect.

Science.gov (United States)

Luc, Raymond; Tortorella, Stephanie M; Ververis, Katherine; Karagiannis, Tom C

2015-04-01

Although oncogenetics remains a critical component of cancer biology and therapeutic research, recent interest has been taken towards the non-genetic features of tumour development and progression, such as cancer metabolism. Specifically, it has been observed that tumour cells are inclined to preferentially undergo glycolysis despite presence of adequate oxygen. First reported by Otto Warburg in the 1920s, and now termed the 'Warburg effect', this aberrant metabolism has become of particular interest due to the prevalence of the fermentation phenotype in a variety of cancers studied. Consequently, this phenotype has proven to play a pivotal role in cancer proliferation. As such Warburg's observations are now being integrated within the modern paradigms of cancer and in this review we explore the role of lactate as an insidious metabolite due to the Warburg effect.

Spatially modulated magnetic structure of EuS due to the tetragonal domain structure of SrTiO3 APS

CERN Document Server

Rosenberg, Aaron J.; Kirtley, John R.; Gedik, Nuh; Moodera, Jagadeesh S.; Moler, Kathryn A.

2017-12-15

The combination of ferromagnets with topological superconductors or insulators allows for new phases of matter that support excitations such as chiral edge modes and Majorana fermions. EuS, a wide-bandgap ferromagnetic insulator with a Curie temperature around 16 K, and SrTiO3 (STO), an important substrate for engineering heterostructures, may support these phases. We present scanning superconducting quantum interference device measurements of EuS grown epitaxially on STO that reveal micron-scale variations in ferromagnetism and paramagnetism. These variations are oriented along the STO crystal axes and only change their configuration upon thermal cycling above the STO cubic-to-tetragonal structural transition temperature at 105 K, indicating that the observed magnetic features are due to coupling between EuS and the STO tetragonal structure. We speculate that the STO tetragonal distortions may strain the EuS, altering the magnetic anisotropy on a micron scale. This result demonstrates that local variation in...

Structural effects on fusion reactor blankets due to liquid metals in magnetic fields

International Nuclear Information System (INIS)

Lehner, J.R.; Reich, M.; Powell, J.R.

1976-01-01

The transient stress distribution caused in the blanket structure when the plasma current suddenly switches off in a time short compared to the L/R decay time of the liquid metal blanket was studied. Poloidal field of the plasma will induce a current to flow in the liquid metal and blanket walls. Since the resistance of the liquid lithium will be much less than that of the metal walls, the current can be considered as flowing around the blanket near the cross section perimeter, but in the lithium

Effective Dose Equivalent To The Cypriot Population Due To Natural Radiation

Energy Technology Data Exchange (ETDEWEB)

Christofides, S [Medical Physics Department, Nicosia General Hospital (Cyprus)

1994-12-31

A study was initiated by the Biomedical Research Foundation, two years ago, to estimate the various natural radiation components that contribute to the Effective Dose Equivalent (EDE) to the Cypriot population. The present study has shown that the contribution due to cosmic radiation is estimated to be less than 270 microSiverts per annum, while that due to airborne Rn-222 concentration in Cypriot houses is estimated to be less then 330 microSieverts per annum. The contribution due to terrestrial gamma radiations, which is currently under investigation, is so far estimated to be around 108 microSieverts per annum. Therefore the EDE to the Cypriot population due to natural radiation is likely to be around 700 microSieverts per annum, not taking into account the internal exposure due to other naturally occuring radionuclides. (author). 7 refs, 4 figs, 4 tabs.

Sodium environment effects to structural materials for fast reactors

International Nuclear Information System (INIS)

Hasegawa, Masayoshi; Fujimura, Tadato; Kondo, Tatsuo; Okabayashi, Kunio; Matsumoto, Keishi.

1976-03-01

Among the material technology for liquid metal-cooling fast breeder reactors, the characteristic points are high temperature, liquid sodium as a heat medium, and high energy-high density neutron energy spectra, accordingly the secular change of materials due to these factors must be taken into the design. The project of material tests in sodium was started from the metallographical studies on corrosion and mass transfer phenomena in sodium environment, and was evolved to the tests and studies on short time strength, creep strength, fatigue strength, and embrittlement in sodium environment. Concerning the corrosion and mass transfer tests, low purity and medium purity material testing loops were employed, and the test of immersion in sodium was carried out. Domestically produced austenitic stainless steel and Cr-Mo steel were tested, and the measurement of weight change, surface inspection, and the observation of cross sectional structure were carried out before and after the immersion. The decrease of thickness due to the leaching of surface metal and the lowering of strength due to the change of composition or structure come into question only in case of very thin walled stainless tubes, and the lowering of heat transfer is negligible. Cr-Mo steel also showed good corrosion resistance in sodium, but the effect of decarbonization on the strength needs some investigation in the production specifications. (Kako, I.)

Nuclear effects in the F3 structure function for finite and asymptotic Q2

International Nuclear Information System (INIS)

Kulagin, S.A.

1998-01-01

We study nuclear effects in the structure function F 3 which describes the parity violating part of the charged-current neutrino nucleon deep inelastic scattering. Starting from a covariant approach we derive a factorized expression for the nuclear structure function in terms of the nuclear spectral function and off-shell nucleon structure functions valid for arbitrary momentum transfer Q and in the limit of weak nuclear binding, i.e. when a nucleus can be treated as a non-relativistic system. We develop a systematic expansion of nuclear structure functions in terms of a Q -2 series caused by nuclear effects (''nuclear twist'' series). Basing ourselves on this expansion we calculate nuclear corrections to the Gross-Llewellyn-Smith sum rule as well as to higher moments of F 3 . We show that corrections to the GLS sum rule due to nuclear effects cancel out in the Bjorken limit and calculate the corresponding Q -2 correction. Special attention is paid to the discussion of the off-shell effects in the structure functions. A sizable impact of these effects both on the Q 2 and x dependence of nuclear structure functions is found. (orig.)

Side effects of anabolic androgenic steroids: pathological findings and structure-activity relationships.

Science.gov (United States)

Büttner, Andreas; Thieme, Detlef

2010-01-01

Side effects of anabolic steroids with relevance in forensic medicine are mainly due to life-threatening health risks with potential fatal outcome and cases of uncertain limitations of criminal liability after steroid administration. Both problems are typically associated with long-term abuse and excessive overdose of anabolic steroids. Side effects may be due to direct genomic or nongenomic activities (myotrophic, hepatotoxic), can result from down-regulation of endogenous biosynthesis (antiandrogenic) or be indirect consequence of steroid biotransformation (estrogenic).Logically, there are no systematic clinical studies available and the number of causally determined fatalities is fairly limited. The following compilation reviews typical abundant observations in cases where nonnatural deaths (mostly liver failure and sudden cardiac death) were concurrent with steroid abuse. Moreover, frequent associations between structural characteristics and typical side effects are summarized.

Tsunamis effects at coastal sites due to offshore faulting

International Nuclear Information System (INIS)

Miloh, T.; Striem, H.L.

1976-07-01

Unusual waves (tsunamis) triggered by submarine tectonic activity such as a fault displacement in the sea bottom may have considerable effect on a coastal site. The possiblity of such phenomena to occur at the southern coast of Israel due to a series of shore-parallel faults, about twenty kilometers offshore, is examined in this paper. The analysis relates the energy or the momentum imparted to the body of water due to a fault displacement of the sea bottom to the energy or the momentum of he water waves thus created. The faults off the Ashdod coast may cause surface waves with amplitudes of about five metres and periods of about one third of an hour. It is also considered that because of the downward movement of the faulted blocks a recession of the sea level rather than a flooding would be the first and the predominant effect at the shore, and this is in agreement with some historical reports. The analysis here presented might be of interest to those designing coastal power plants. (author)

Effectiveness of multi tuned liquid dampers with slat screens for reducing dynamic responses of structures

Science.gov (United States)

Nguyen, T. P.; Pham, D. T.; Ngo, K. T.

2018-04-01

Reducing vibration in structures under lateral load always attracts many researchers in during pastime, hence the mainly purpose of paper analyzes effectiveness of multiple-tuned liquid dampers for reducing dynamic responses of structures under ground acceleration of earthquakes. In this study, the multi-tuned liquid damper with slat screens (M-TLDWSS) is considered in detail for analyzing dynamic response of multi-degrees of freedom structure due to earthquake, which is more different previous studies. Then, the general equation of motion of the structure and M-TLDWSS under ground acceleration of earthquake is established based on dynamic balance of principle and solved by numerical method in the time domain. The effects of characteristic parameters of M-TLDWSS on dynamic response of the structure are investigated. The results obtained in this study demonstrate that the M-TLDWSS has significantly effectiveness for reducing dynamic response of the structure.

Crystal orientation effects on the piezoelectric field of strained zinc-blende quantum-well structures

DEFF Research Database (Denmark)

Duggen, Lars; Willatzen, Morten; Lassen, Benny

2008-01-01

direction show important changes in strain and the electric distribution due to piezoelectric effects. The findings indicate the quantitative importance of a fully coupled model even for zinc blende, in particular when discussing electronic band structure and optoelectronic properties....

Suspensions of polymer-grafted nanoparticles with added polymers-Structure and effective pair-interactions.

Science.gov (United States)

Chandran, Sivasurender; Saw, Shibu; Kandar, A K; Dasgupta, C; Sprung, M; Basu, J K

2015-08-28

We present the results of combined experimental and theoretical (molecular dynamics simulations and integral equation theory) studies of the structure and effective interactions of suspensions of polymer grafted nanoparticles (PGNPs) in the presence of linear polymers. Due to the absence of systematic experimental and theoretical studies of PGNPs, it is widely believed that the structure and effective interactions in such binary mixtures would be very similar to those of an analogous soft colloidal material-star polymers. In our study, polystyrene-grafted gold nanoparticles with functionality f = 70 were mixed with linear polystyrene (PS) of two different molecular weights for obtaining two PGNP:PS size ratios, ξ = 0.14 and 2.76 (where, ξ = Mg/Mm, Mg and Mm being the molecular weights of grafting and matrix polymers, respectively). The experimental structure factor of PGNPs could be modeled with an effective potential (Model-X), which has been found to be widely applicable for star polymers. Similarly, the structure factor of the blends with ξ = 0.14 could be modeled reasonably well, while the structure of blends with ξ = 2.76 could not be captured, especially for high density of added polymers. A model (Model-Y) for effective interactions between PGNPs in a melt of matrix polymers also failed to provide good agreement with the experimental data for samples with ξ = 2.76 and high density of added polymers. We tentatively attribute this anomaly in modeling the structure factor of blends with ξ = 2.76 to the questionable assumption of Model-X in describing the added polymers as star polymers with functionality 2, which gets manifested in both polymer-polymer and polymer-PGNP interactions especially at higher fractions of added polymers. The failure of Model-Y may be due to the neglect of possible many-body interactions among PGNPs mediated by matrix polymers when the fraction of added polymers is high. These observations point to the need for a new framework to

Beam loading effects in a standing wave accelerator structure

International Nuclear Information System (INIS)

Arai, Shigeaki; Katayama, Takeshi; Tojyo, Eiki; Yoshida, Katsuhide.

1978-11-01

The steady-state beam loading effects on the accelerating field in the disk-loaded structure of a standing wave type have been systematically studied. The electron bunch from a 15 MeV electron linac is injected at arbitrary phase of the external driving field in the test structure. The change of the phase shift of the accelerating field and that of the stored energy are measured as a function of the phase on which the bunch rides. The former shows drastic change when the bunch is around the crest of the driving field and when the beam loading is heavy, whereas the latter varies sinusoidally for any beam loading. The resonant frequency shift of the structure due to beam loading is estimated by using the measured results. All the experimental results are well explained by the normal mode analysis of the microwave cavity theory. (author)

Structural equation modelling of lower back pain due to whole-body vibration exposure in the construction industry.

Science.gov (United States)

Vitharana, Vitharanage Hashini Paramitha; Chinda, Thanwadee

2017-09-21

Whole-body vibration (WBV) exposure is a health hazard among workers, causing lower back pain (LBP) in the construction industry. This study examines key factors affecting LBP due to WBV exposure using exploratory factor analysis and structural equation modelling. The results confirm five key factors (equipment, job related, organizational, personal, social context) with their 17 associated items. The organizational factor is found the most important, as it influences the other four factors. The results also show that appropriate seat type, specific training programme, job rotation, workers' satisfaction and workers' physical condition are crucial in reducing LBP due to WBV exposure. Moreover, provision of new machines without proper training and good working condition might not help reduce LBP due to WBV exposure. The results help the construction companies to better understand key factors affecting LBP due to WBV exposure, and to plan for a better health improvement programme.

Potential Settlement Due to Seismic Effects in the Residential Area of Ilgin (Konya, Turkey

Directory of Open Access Journals (Sweden)

Adnan Ozdemir

2016-04-01

Full Text Available Ilgin lies on newly formed, loose, granular deposits, and there is a substantial risk for surface liquefaction and foundation settlements due to the seismic effects resulting from groundwater close to the surface. This study evaluates potential settlement due to seismic effects in the residential areas of Ilgin using the Standard Penetration Test (SPT performed on 45 geotechnical bores. In Turkey, where earthquakes occur frequently, the selection of residential areas is of great importance. In this research, the number of settlements was calculated considering an earthquake having a Local Magnitude of 6 (i.e., ML ≥ 6.0 and a ≥ 0.4 g under a 0.4 g seismic force, and a potential settlement map of the residential area was prepared. The amount of settlement exceeds 20 cm at locations near Ilgin Lake and in the northern section of Ilgin residential areas; downtown, the settlement ranges from 10-20 cm. The settlements presented here exceed the allowable threshold limits for structures constructed using adobe and brick in this district. Thus, improvements to minimize earthquake-induced damages are required for structures in Ilgin. Moreover, the selection of new residential areas, along with the proper design of the structures before construction, should be examined further to avoid ground liquefaction and structure damage due to settlement.    Resumen La localidad de Ilgin está ubicada sobre depósitos recién formados, granulares y no compactos, por lo que existe un riesgo sustancial de licuefacción de la superficie y la creación de asentamientos o deslizamientos debido a los efectos sísmicos resultantes del agua subterránea poco profunda. Este artículo evalúa el potencial de asentamiento debido a los efectos sísmicos en las áreas residenciales de Ilgin a través del Ensayo de Penetración Estándar (SPT, en inglés realizado en 45 perforaciones geotécnicas. En Turquía, donde los terremotos ocurren frecuentemente, la selección de �

Effect of soil–structure interaction on the reliability of reinforced concrete bridges

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Kamel Bezih

2015-09-01

Full Text Available In the design of reinforced concrete (RC bridges, the random and nonlinear behavior of soil may lead to insufficient reliability levels. For this reason, it is necessary to take into account the variability of soil properties which can significantly affect the bridge behavior regarding ultimate and serviceability limit states. This study investigates the failure probability for existing reinforced concrete bridges due to the effects of interaction between the soil and the structure. In this paper, a coupled reliability–mechanical approach is developed to study the effect of soil–structure interaction for RC bridges. The modeling of this interaction is incorporated into the mechanical model of RC continuous beams, by considering nonlinear elastic soil stiffness. The reliability analysis highlights the large importance of soil–structure interaction and shows that the structural safety is highly sensitive to the variability of soil properties, especially when the nonlinear behavior of soil is considered.

Effect of waste wax and chain structure on the mechanical and physical properties of polyethylene

Directory of Open Access Journals (Sweden)

M.A. AlMaadeed

2015-05-01

The wax dispersion in the matrix strongly depends on the percentage of wax added to the polymer and the molecular structure of the polymer. It was found that increasing the wax content enhances the phase separation. LDPE undergoes less phase separation due to its highly branched structure composed of a network of short and long chain branches. The wax has no pronounced plasticising effect on the polymer. This is clearly manifested in LDPE as no change in the melting temperature occurred. LLDPE and HDPE were slightly affected by a high concentration of wax (30% and 40%. This is due to the non-uniform distribution of short chain branching along the LLDPE and HDPE main chains, which can interact with the wax structure.

Structural evolution due to Zn and Te adsorption on As-exposed Si(211): density functional calculation

International Nuclear Information System (INIS)

Gupta, Bikash C; Konar, Shyamal; Grein, C H; Sivananthan, S

2009-01-01

Systematic theoretical investigations are carried out under the density functional formalism in an effort to understand the initial structural evolution due to the adsorption of ZnTe on As-exposed Si(211). Our calculations indicate that after the adsorption of Zn and Te on the As-exposed Si(211), the stable atomic structure qualitatively follows the ideal atomic structure of Si(211) with alteration of various bond lengths. Since the basic symmetry of the Si(211) is preserved after the adsorption of ZnTe, the deposition of ZnTe on the As terminated Si(211) prior to the deposition of CdTe and HgCdTe is useful for obtaining an ultimate quality layer of HgCdTe on Si(211). Some of our results are compared with the available experimental results, and they are found to agree with each other qualitatively.

Structural and surface changes in glassy carbon due to strontium implantation and heat treatment

Science.gov (United States)

Odutemowo, O. S.; Malherbe, J. B.; Prinsloo, L. C.; Njoroge, E. G.; Erasmus, R.; Wendler, E.; Undisz, A.; Rettenmayr, M.

2018-01-01

There are still questions around the microstructure of glassy carbon (GC), like the observation of the micropores. These were proposed to explain the low density of GC. This paper explains the effect of ion bombardment (200 keV Sr+, 1 × 1016 Sr+/cm2 at RT) on the microstructure of GC. TEM and AFM show that micropores in pristine GC are destroyed leading to densification of GC from 1.42 g/cm3 to 2.03 g/cm3. The amorphisation of glassy carbon was also not complete with graphitic strands embedded within the GC. These were relatively few, as Raman analysis showed that the Sr implantation resulted in a typical amorphous Raman spectrum. Annealing of the sample at 900 °C only resulted in a slight recovery of the GC structure. AFM and SEM analysis showed that the surface of the sample became rougher after Sr implantation. The roughness increased after the sample was annealed at 600 °C due to segregation of Sr towards the surface of the GC. SEM measurements of a sample with both implanted and un-implanted edges after annealing at 900 °C, showed that the high temperature heat treatment did not affect the surface topography of un-irradiated GC.

Local impact effects on concrete target due to missile: An empirical and numerical approach

International Nuclear Information System (INIS)

Ranjan, Rajiv; Banerjee, Sauvik; Singh, R.K.; Banerji, Pradipta

2014-01-01

Highlights: • Local impact effect of hard missile on reinforced concrete targets has been studied. • Review of empirical formulation for predicting local response carried out. • Numerical simulation of experimental test of Kojima (1991) carried out. • Divergence of FE results with those obtained using emperical formulations. • Close match of numerical simulation results with experimental data. - Abstract: Concrete containment walls and internal concrete barrier walls of a Nuclear Power Plant safety related structures are often required to be designed for externally and internally generated missiles. Potential missiles include external extreme wind generated missiles, aircraft crash and internal accident generated missiles such as impact due to turbine blade failure and steel pipe missiles resulting from pipe break. The objective of the present paper is to compare local missile impact effects on reinforced concrete target using available empirical formulations with those obtained using LS-DYNA numerical simulation. The use of numerical simulations for capturing the transient structural response has become increasingly used for structural design against impact loads. They overcome the limits of applicability of the empirical formulae and also provide information on stress and deformation fields, which may be used to improve the resistance of the concrete. Finite element (FE) analyses of an experimental impact problem reported by Kojima (1991) are carried out that are able to capture the missile impact effects; in terms of local and global damage. The continuous surface cap model has been used for modelling concrete behaviour. A range of missile velocity has been considered to simulate local missile impact phenomenon and modes of failure and to capture the concrete response from elastic to plastic fracture. A comparison is then made between the empirical formulations, numerical simulation results, and available experimental results of slab impact tests

Effect on thermoluminescence parameters of biotite mineral due to thermal quenching

International Nuclear Information System (INIS)

Kalita, J.M.; Wary, G.

2012-01-01

The Thermally Stimulated Luminescence (TSL) at room temperature X-ray irradiated natural biotite in form of micro-grain powder was studied under various heating rates. TSL peaks showed at temperatures 393 K, 399.6 K, 403.5 K, 404.5 K, 406.9 K at their respective heating rates 2 K/s, 4 K/s, 6 K/s, 8 K/s and 10 K/s. The effect of thermal quenching on thermoluminescence parameters such as peak maximum temperature, peak area, FWHM, geometrical symmetry factor, the activation energy were investigated. From the symmetry factor it is clear that the TL glow curve follows the first order kinetics for the lowest heating rate, but as the heating rate increases it defers from the first order. The activation energies for each heating rates were calculated by using Chen peak shape methods for general order kinetics and found to be decreased for higher heating rates. When activation energy is calculated by variable heating rate method it is observed that the method overestimated the value of activation energy and pre-exponential frequency factor significantly due to thermal quenching. - Highlights: ► Biotite is a common mineral with chemical formula K(Mg,Fe) 3 AlSi 3 O 10 (F,OH) 2 . ► Structural, compositional and elemental analysis of biotite is carried out. ► TSL of X-ray irradiated natural biotite was studied under various heating rates. ► The effect of thermal quenching on TL parameters has been investigated.

Grain boundary barrier modification due to coupling effect of crystal polar field and water molecular dipole in ZnO-based structures

International Nuclear Information System (INIS)

Ji, Xu; Zhu, Yuan; Chen, Mingming; Su, Longxing; Chen, Anqi; Zhao, Chengchun; Gui, Xuchun; Xiang, Rong; Huang, Feng; Tang, Zikang

2014-01-01

Surface water molecules induced grain boundaries (GBs) barrier modification was investigated in ZnO and ZnMgO/ZnO films. Tunable electronic transport properties of the samples by water were characterized via a field effect transistor (FET) device structure. The FETs fabricated from polar C-plane ZnO and ZnMgO/ZnO films that have lots of GBs exhibited obvious double Schottky-like current-voltage property, whereas that fabricated from nonpolar M-plane samples with GBs and ZnO bulk single-crystal had no obvious conduction modulation effects. Physically, these hallmark properties are supposed to be caused by the electrostatical coupling effect of crystal polar field and molecular dipole on GBs barrier.

MnFe(PGe) compounds: Preparation, structural evolution, and magnetocaloric effects

International Nuclear Information System (INIS)

Yue Ming; Zhang Hong-Guo; Zhang Jiu-Xing; Liu Dan-Min

2015-01-01

The interdependences of preparation conditions, magnetic and crystal structures, and magnetocaloric effects (MCE) of the MnFePGe-based compounds are reviewed. Based upon those findings, a new method for the evaluation of the MCE in these compounds, based on differential scanning calorimetry (DSC), is proposed. The MnFePGe-based compounds are a group of magnetic refrigerants with giant magnetocaloric effect (GMCE), and as such, have drawn tremendous attention, especially due to their many advantages for practical applications. Structural evolution and phase transformation in the compounds as functions of temperature, pressure, and magnetic field are reported. Influences of preparation conditions upon the homogeneity of the compounds’ chemical composition and microstructure, both of which play a key role in the MCE and thermal hysteresis of the compounds, are introduced. Lastly, the origin of the “virgin effect” in the MnFePGe-based compounds is discussed. (paper)

Theoretical study of relativistic effects in the electronic structure and chemical bonding of UF6

International Nuclear Information System (INIS)

Onoe, Jun; Takeuchi, Kazuo; Sekine, Rika; Nakamatsu, Hirohide; Mukoyama, Takeshi; Adachi, Hirohiko.

1992-01-01

We have performed the relativistic molecular orbital calculation for the ground state of UF 6 , using the discrete-variational Dirac-Slater method (DV-DS), in order to elucidate the relativistic effects in the electronic structure and chemical bonding. Compared with the electronic structure calculated by the non-relativistic Hartree-Fock-Slater (DV-X α )MO method, not only the direct relativistic effects (spin-orbit splitting etc), but also the indirect effect due to the change in screening core potential charge are shown to be important in the MO level structure. From the U-F bond overlap population analysis, we found that the U-F bond formation can be explained only by the DV-DS, not by the DV-X α . The calculated electronic structure in valence energy region (-20-OeV) and excitation energies in UV region are in agreement with experiments. (author)

Effects of concentration, head group, and structure of surfactants on the degradation of phenanthrene

International Nuclear Information System (INIS)

Jin Danyue; Jiang Xia; Jing Xin; Ou Ziqing

2007-01-01

The effects of concentration, polar/ionic head group, and structure of surfactants on the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in the aqueous phase, as well as their effects on the bacterial activity were investigated. The toxicity ranking of studied surfactants is: non-ionic surfactants (Tween 80, Brij30, 10LE and Brij35) -1 ) served the sole carbon and energy resource. However, the degradation of 14 C-phenanthrene showed either a decrease or no obvious change with the surfactants present at all tested concentrations (5-40 mg L -1 ). Thus, the surfactant addition is not beneficial to the removal of phenanthrene or other PAH contaminants due presumably to the preferential utilization of surfactants at low levels as the non-toxic nutrient resource and to the high toxicity of the surfactants at high levels to the microorganism activity. Biodegradation of phenanthrene was also influenced by the surfactant concentration, head group type, and structure. Much more research has yet to be completed on the use of surfactants for soil remediation due to the surfactant toxicity or biodegradation effect

Effect of intratympanic dexamethasone, memantine and piracetam on cellular apoptosis due to cisplatin ototoxicity.

Science.gov (United States)

Topdag, M; Iseri, M; Gelenli, E; Yardimoglu, M; Yazir, Y; Ulubil, S A; Topdag, D O; Ustundag, E

2012-11-01

This study aimed to contribute to the literature on the prevention and treatment of ototoxicity due to various drugs and chemicals. This study compared the histological effects of intratympanic dexamethasone, memantine and piracetam on cellular apoptosis due to cisplatin ototoxicity, in 36 rats. Dexamethasone and memantine had significant effects on the stria vascularis, organ of Corti and spiral ganglion (p piracetam decreased the apoptosis rate, this effect was not statistically significant (p > 0.05). Dexamethasone and memantine were found superior to piracetam in reducing apoptosis due to cisplatin ototoxicity. Further studies of this subject are needed, incorporating electron microscopy and auditory brainstem response testing.

Basic equations of the quasiparticle-phonon nuclear model with the effects due to the Pauli principle and the phonon ground state correlations

International Nuclear Information System (INIS)

Nguyen Dinh Dang; Voronov, V.V.

1983-01-01

A system of basic equations of the quasiparticle-phonon model is obtained for energies and a structure of excited states described by the wave functions containing one- and two-phonon components. The effects due to the Pauli principle for two-phonon components and the phonon ground state correlations of a spherical nucleus are taken here into account. The quantitative estimations of these effects are given by a simplified scheme. The relation between these equations with the results from other theoretical approaches is discussed

76 FR 59113 - Extension of the Due Date for Submitting Information on How to Structure Proposed New Program...

Science.gov (United States)

2011-09-23

... manufacturing research needs, and issue sub-awards to fund research by universities, government laboratories, and U.S. businesses. This initiative would support research and development (R&D) in advanced...-02] Extension of the Due Date for Submitting Information on How to Structure Proposed New Program...

Maternal Parenting Style and Delinquency by Race and the Moderating Effect of Structural Disadvantage

Science.gov (United States)

Mowen, Thomas J.; Schroeder, Ryan D.

2018-01-01

Contemporary research suggests authoritative parenting is the most effective parenting style in deterring juvenile delinquency. Some research has found there are differences in parenting style between racial groups due to structural disadvantage faced by marginalized individuals. Yet, relatively little is known about how racial differences in…

Analysis of the overall structural behavior due to the impact of deformable missiles

International Nuclear Information System (INIS)

Ettouney, M.M.; Radini, R.R.; Hsueh, P.S.

1979-01-01

This paper presents a method of analysis to evaluate the overall behavior of reinforced concrete structures subjected to impact from deformable missiles. This method approaches the analysis in a very simple and practical way. The analysis is based on approximating the structure-missile system by a two-degree of freedom model. The two degrees of freedom model represents the missile and the structure, respectively. The hysteretic damping effects are considered implicitly through the nonlinearity of the two springs. Empirical formulas are presented for the evaluation of the dynamic properties of the nonlinear spring representing the concrete structure. The impact is simulated by applying an impulse on the two degrees of freedom system, then by the method of step by step numerical time integration (central difference formula is used) the time histories of the displacements and velocities of both the missile and structure are obtained. The numerical procedure is simple enough to be programmed by a hand or desk calculator which makes the method handy for most engineers and analysis. (orig.)

Passive noise control by enhancing aeroacoustic interference due to structural discontinuities in close proximity

Science.gov (United States)

Leung, R. C. K.; So, R. M. C.; Tang, S. K.; Wang, X. Q.

2011-07-01

In-duct devices are commonly installed in flow ducts for various flow management purposes. The structural construction of these devices indispensably creates disruption to smooth flow through duct passages so they exist as structural discontinuities in duct flow. The presence of these discontinuities provides additional possibility of noise generation. In real practice, in-duct devices do not exist alone in any duct system. Even though each in-duct device would generate its own noise, it might be possible that these devices could be properly arranged so as to strengthen the interference between individual noise; thus giving rise to an overall reduction of noise radiation in the in-duct far field. This concept of passive noise control is investigated by considering different configurations of two structural discontinuities of simple form (i.e., a cavity) in tandem in an unconfined flow and in opposing setting within a flow duct. It is known that noise generated by a cavity in unconfined domain (unconfined cavity) is strongly dependent on flow-resonant behavior within the cavity so the interference it produces is merely aeroacoustic. The objective of the present study is to verify the concept of passive noise reduction through enhancement of aeroacoustic interference due to two cavities by considering laminar flow only. A two-dimensional approach is adopted for the direct aeroacoustic calculations using a direct numerical simulation (DNS) technique. The position and geometries of the cavities and the Mach number are varied; the resultant aeroacoustic behavior and acoustic power are calculated. The numerical results are compared with a single cavity case to highlight the effect of introducing additional cavities to the aeroacoustic problem. Resonant flow oscillations occur when two unconfined cavities are very close and the associated acoustic field is very intense with no noise reduction possible. However, for duct aeroacoustics, it is found that a 7.9 db reduction

Centrifuge modelling of seismic soil structure interaction effects

International Nuclear Information System (INIS)

Ghosh, B.; Madabhushi, S.P.G.

2007-01-01

Proper understanding of the role of unbounded soil in the evaluation of dynamic soil structure interaction (SSI) problem is very important for structures used in the nuclear industry. In this paper, the results from a series of dynamic centrifuge tests are reported. These tests were performed on different types of soil stratifications supporting a rigid containment structure. Test results indicate that accelerations transmitted to the structure's base are dependent on the stiffness degradation in the supporting soil. Steady build up of excess pore pressure leads to softening of the soil, which decreases the shear modulus and shear strength and subsequently changes the dynamic responses. It is also shown that the presence of the structure reduces the translational component of the input base motion and induces rocking of the structure. The test results are compared with some standard formulae used for evaluating interaction in the various building codes. It was concluded that the dynamic shear modulus values used should be representative of the site conditions and can vary dramatically due to softening. Damping values used are still very uncertain and contain many factors, which cannot be accounted in the experiments. It is emphasized that simplified design processes are important to gain an insight into the behaviour of the physical mechanism but for a complete understanding of the SSI effects sophisticated methods are necessary to account for non-linear behaviour of the soil material

Diagnostic tool for structural health monitoring: effect of material nonlinearity and vibro-impact process

Science.gov (United States)

Hiwarkar, V. R.; Babitsky, V. I.; Silberschmidt, V. V.

2013-07-01

Numerous techniques are available for monitoring structural health. Most of these techniques are expensive and time-consuming. In this paper, vibration-based techniques are explored together with their use as diagnostic tools for structural health monitoring. Finite-element simulations are used to study the effect of material nonlinearity on dynamics of a cracked bar. Additionally, several experiments are performed to study the effect of vibro-impact behavior of crack on its dynamics. It was observed that a change in the natural frequency of the cracked bar due to crack-tip plasticity and vibro-impact behavior linked to interaction of crack faces, obtained from experiments, led to generation of higher harmonics; this can be used as a diagnostic tool for structural health monitoring.

High temperature annealing effect on structural and magnetic properties of Ti/Ni multilayers

International Nuclear Information System (INIS)

Bhatt, Pramod; Ganeshan, V.; Reddy, V.R.; Chaudhari, S.M.

2006-01-01

High temperature annealing effect on structural and magnetic properties of Ti/Ni multilayer (ML) up to 600 deg. C have been studied and reported in this paper. Ti/Ni multilayer samples having constant layer thicknesses of 50 A each are deposited on float glass and Si(1 1 1) substrates using electron-beam evaporation technique under ultra-high vacuum (UHV) conditions at room temperatures. The micro-structural parameters and their evolution with temperature for as-deposited as well as annealed multilayer samples up to 600 deg. C in a step of 100 deg. C for 1 h are determined by using X-ray diffraction (XRD) and grazing incidence X-ray reflectivity techniques. The X-ray diffraction pattern recorded at 300 deg. C annealed multilayer sample shows interesting structural transformation (from crystalline to amorphous) because of the solid-state reaction (SSR) and subsequent re-crystallization at higher temperatures of annealing, particularly at ≥400 deg. C due to the formation of TiNi 3 and Ti 2 Ni alloy phases. Sample quality and surface morphology are examined by using atomic force microscopy (AFM) technique for both as-deposited as well as annealed multilayer samples. In addition to this, a temperature dependent dc resistivity measurement is also used to study the structural transformation and subsequent alloy phase formation due to annealing treatment. The corresponding magnetization behavior of multilayer samples after each stage of annealing has been investigated by using Magneto-Optical Kerr Effect (MOKE) technique and results are interpreted in terms of observed micro-structural changes

EFFECT OF DEXTRAN-graft-POLYACRYLAMIDE INTERNAL STRUCTURE ON FLOCCULATION PROCESS PARAMETERS

International Nuclear Information System (INIS)

Bezugla, T.; Kutsevol, N.; Shyichuk, A.; Ziolkowska, D.

2008-01-01

Dextran-graft-Polyacrylamide copolymers (D-g-PAA) of brush-like architecture were tested as flocculation aids in the model kaolin suspensions. Due to expanded conformation the D-g-PAA copolymers are more effective flocculants than individual PAA with close molecular mass. The internal structure of D-g-PAA copolymers which is determined by number and length of grafted PAA chains, the distance between grafts, etc., has the significant influence on flocculation behavior of such polymers

Track structure based modelling of light ion radiation effects on nuclear and mitochondrial DNA

Science.gov (United States)

Schmitt, Elke; Ottolenghi, Andrea; Dingfelder, Michael; Friedland, Werner; Kundrat, Pavel; Baiocco, Giorgio

2016-07-01

Space radiation risk assessment is of great importance for manned spaceflights in order to estimate risks and to develop counter-measures to reduce them. Biophysical simulations with PARTRAC can help greatly to improve the understanding of initial biological response to ionizing radiation. Results from modelling radiation quality dependent DNA damage and repair mechanisms up to chromosomal aberrations (e.g. dicentrics) can be used to predict radiation effects depending on the kind of mixed radiation field exposure. Especially dicentric yields can serve as a biomarker for an increased risk due to radiation and hence as an indicator for the effectiveness of the used shielding. PARTRAC [1] is a multi-scale biophysical research MC code for track structure based initial DNA damage and damage response modelling. It integrates physics, radiochemistry, detailed nuclear DNA structure and molecular biology of DNA repair by NHEJ-pathway to assess radiation effects on cellular level [2]. Ongoing experiments with quasi-homogeneously distributed compared to sub-micrometre focused bunches of protons, lithium and carbon ions allow a separation of effects due to DNA damage complexity on nanometre scale from damage clustering on (sub-) micrometre scale [3, 4]. These data provide an unprecedented benchmark for the DNA damage response model in PARTRAC and help understand the mechanisms leading to cell killing and chromosomal aberrations (e.g. dicentrics) induction. A large part of space radiation is due to a mixed ion field of high energy protons and few heavier ions that can be only partly absorbed by the shielding. Radiation damage induced by low-energy ions significantly contributes to the high relative biological efficiency (RBE) of ion beams around Bragg peak regions. For slow light ions the physical cross section data basis in PARTRAC has been extended to investigate radiation quality effects in the Bragg peak region [5]. The resulting range and LET values agree with ICRU data

Long-range spin-singlet proximity effect for a Josephson system with a single-crystal ferromagnet due to its band-structure features

Science.gov (United States)

Avdeev, M. V.; Proshin, Yu. N.

2018-03-01

A possible explanation for the long-range proximity effect observed in single-crystalline cobalt nanowires sandwiched between two tungsten superconducting electrodes [Nat. Phys. 6, 389 (2010), 10.1038/nphys1621] is proposed. The theoretical model uses properties of a ferromagnet band structure. Specifically, to connect the exchange field with the momentum of quasiparticles the distinction between the effective masses in majority and minority spin subbands and the Fermi-surface anisotropy are considered. The derived Eilenberger-like equations allowed us to obtain a renormalized exchange interaction that is completely compensated for some crystallographic directions under certain conditions. The proposed theoretical model is compared with previous approaches.

Stochastic health effects assessment due to short-term external exposure

International Nuclear Information System (INIS)

Raicevic, J.J.; Raskob, W.; Merkle, M.; Ninkovic, M.M.

2001-01-01

The new model for calculation of stochastic health effects is presented in this paper. The exposure pathways which are briefly considered are the short-term external exposure due to passage of the radioactive cloud (cloudshine) and the short-term external exposure due to radioactive material deposited on skin and clothes (skin contamination). The quantitative assessment of stochastic effects is expressed in numbers of deaths, which are given as a functions of the time at the accident, and age at death, what on the other side enables estimation of the number of deaths within the specified range of the time/age parameters. That means the model calculates the number of deaths within one particular year, summed up over all ages at deaths, or vice versa, it finds the number of deaths within the specified range of ages at death, summed up over all observation times. Results presented in this paper are implemented in the module LATEHEAL, which is incorporated in RODOS, a new European system for decision support for nuclear emergencies. (author)

Spin-orbit coupling effects in indium antimonide quantum well structures

Science.gov (United States)

Dedigama, Aruna Ruwan

Indium antimonide (InSb) is a narrow band gap material which has the smallest electron effective mass (0.014m0) and the largest electron Lande g-facture (-51) of all the III-V semiconductors. Spin-orbit effects of III-V semiconductor heterostructures arise from two different inversion asymmetries namely bulk inversion asymmetry (BIA) and structural inversion asymmetry (SIA). BIA is due to the zinc-blende nature of this material which leads to the Dresselhaus spin splitting consisting of both linear and cubic in-plane wave vector terms. As its name implies SIA arises due to the asymmetry of the quantum well structure, this leads to the Rashba spin splitting term which is linear in wave vector. Although InSb has theoretically predicted large Dresselhaus (760 eVA3) and Rashba (523 eA 2) coefficients there has been relatively little experimental investigation of spin-orbit coefficients. Spin-orbit coefficients can be extracted from the beating patterns of Shubnikov--de Haas oscillations (SdH), for material like InSb it is hard to use this method due to the existence of large electron Lande g-facture. Therefore it is essential to use a low field magnetotransport technique such as weak antilocalization to extract spin-orbit parameters for InSb. The main focus of this thesis is to experimentally determine the spin-orbit parameters for both symmetrically and asymmetrically doped InSb/InxAl 1-xSb heterostructures. During this study attempts have been made to tune the Rashba spin-orbit coupling coefficient by using a back gate to change the carrier density of the samples. Dominant phase breaking mechanisms for InSb/InxAl1-xSb heterostructures have been identified by analyzing the temperature dependence of the phase breaking field from weak antilocalization measurements. Finally the strong spin-orbit effects on InSb/InxAl1-xSb heterostructures have been demonstrated with ballistic spin focusing devices.

Surface and Internal Waves due to a Moving Load on a Very Large Floating Structure

Directory of Open Access Journals (Sweden)

Taro Kakinuma

2012-01-01

Full Text Available Interaction of surface/internal water waves with a floating platform is discussed with nonlinearity of fluid motion and flexibility of oscillating structure. The set of governing equations based on a variational principle is applied to a one- or two-layer fluid interacting with a horizontally very large and elastic thin plate floating on the water surface. Calculation results of surface displacements are compared with the existing experimental data, where a tsunami, in terms of a solitary wave, propagates across one-layer water with a floating thin plate. We also simulate surface and internal waves due to a point load, such as an airplane, moving on a very large floating structure in shallow water. The wave height of the surface or internal mode is amplified when the velocity of moving point load is equal to the surface- or internal-mode celerity, respectively.

Structure resonances due to space charge in periodic focusing channels

Science.gov (United States)

Li, Chao; Jameson, R. A.

2018-02-01

The Vlasov-Poisson model is one of the most effective methods to study the space charge dominated beam evolution self-consistently in a periodic focusing channel. Since the approach to get the solution with this model is not trivial, previous studies are limited in degenerated conditions, either in smoothed channel (constant focusing) [I. Hofmann, Phys. Rev. E 57, 4713 (1998)] or in alternating gradient focusing channel with equal initial beam emittance condition in the degrees of freedom [I. Hofmann et al., Part. Accel. 13, 145 (1983); Chao Li et al., THOBA02, IPAC2016]. To establish a basis, we intentionally limit this article to the study of the pure transverse periodic focusing lattice with arbitrary initial beam condition, and the same lattice structure in both degrees of freedom, but with possibility of different focusing strengths. This will show the extension of the existing work. The full Hamiltonian is invoked for a pure transverse focusing lattice in various initial beam conditions, revealing different mode structure and additional modes beyond those of the degenerated cases. Application of the extended method to realistic lattices (including longitudinal accelerating elements) and further details will then reveal many new insights, and will be presented in later work.

Effects of air blast on power plant structures and components

International Nuclear Information System (INIS)

Kot, C.A.; Valentin, R.A.; McLennan, D.A.; Turula, P.

1978-10-01

The effects of air blast from high explosives detonation on selected power plant structures and components are investigated analytically. Relying on a synthesis of state of the art methods estimates of structural response are obtained. Similarly blast loadings are determined from compilations of experimental data reported in the literature. Plastic-yield line analysis is employed to determine the response of both concrete and steel flat walls (plates) under impulsive loading. Linear elastic theory is used to investigate the spalling of concrete walls and mode analysis methods predict the deflection of piping. The specific problems considered are: the gross deformation of reinforced concrete shield and containment structures due to blast impulse, the spalling of concrete walls, the interaction or impact of concrete debris with steel containments and liners, and the response of exposed piping to blast impulse. It is found that for sufficiently close-in detonations and/or large explosive charge weights severe damage or destruction will result. This is particularly true for structures or components directly exposed to blast impulse

Giant magnetoelectric effect in negative magnetostrictive/piezoelectric/positive magnetostrictive semiring structure

Science.gov (United States)

Zeng, Lingyu; Zhou, Minhong; Bi, Ke; Lei, Ming

2016-01-01

Magnetoelectric (ME) Ni/PZT/TbFe2 and TbFe2/PZT composites with two semiring structures are prepared. The dependence between ME coupling and magnetostrictive property of the composite is discussed. Because Ni possesses negative magnetostrictive property and TbFe2 shows positive magnetostrictive property, the ME voltage coefficient of Ni/PZT/TbFe2 semiring structure is much larger than that of TbFe2/PZT. In these composites, the ME voltage coefficient increases and the resonance frequency gradually decreases with the increase of the semiring radius, showing that structural parameters are key factors to the composite properties. Due to the strong ME coupling effect, a giant ME voltage coefficient αE = 44.8 V cm-1 Oe-1 is obtained. This approach opens a way for the design of ME composites with giant ME voltage coefficient.

Correlating charge transport to structure in deconstructed diketopyrrolopyrrole oligomers: A case study of a monomer in field-effect transistors

DEFF Research Database (Denmark)

Pickett, Alec; Torkkeli, Mika; Mukhopadhyay, Tushita

2018-01-01

Copolymers based on diketopyrrolopyrrole (DPP) cores have attracted a lot of attention due to their high p-type as well as n-type carrier mobilities in organic field-effect transistors (FETs) and high power conversion efficiencies in solar cell structures. We report the structural and charge tran...

Effect of Large Negative Phase of Blast Loading on Structural Response of RC Elements

Directory of Open Access Journals (Sweden)

Syed Zubair Iman

2016-01-01

Full Text Available Structural response of reinforced concrete (RC elements for analysis and design are often obtained using the positive phase of the blast pressure curve disregarding the negative phase assuming insignificant contribution from the negative phase of the loading. Although, some insight on the effect of negative phase of blast pressure based on elastic single-degree-of-freedom (SDOF analysis was presented before, the influence of negative phase on different types of resistance functions of SDOF models and on realistic finite element analysis has not been explored. In this study, the effects of inclusion of pulse negative phase on structural response of RC elements from SDOF analysis and from more detailed finite element analysis have been investigated. Investigation of SDOF part has been conducted using MATLAB code that utilizes non-linear resistance functions of SDOF model. Detailed numerical investigation using finite element code DIANA was conducted on the significance of the negative phase on structural response. In the FE model, different support stiffness was used to explore the effect of support stiffness on the structural response due to blast negative phase. Results from SDOF and FE analyses present specific situations where the effect of large negative phase was found to be significant on the structural response of RC elements.

Single-particle effects in fine structure of super-asymmetric fission

International Nuclear Information System (INIS)

Mirea, M.

1999-01-01

Energy spectrum measurements concerning the 14 C decay from 223 Ra revealed a fine structure with an intense branch on the excited state of the daughter 209 Pb. Apart the great number of microscopic--macroscopic attempts of different authors in describing this behavior (compiled recently), this phenomenon was explained quantitatively using the Landau--Zener effect, i.e., the promotion mechanism of a unpaired nucleon between two levels characterised by the same quantum numbers connected to some symmetries of the nuclear system in the region where an avoided level crossing is exhibited. The adiabatic levels during the super-asymmetric fission process were determined with a new version of the two--centre shell model especially constructed for very large mass--asymmetries. The half--lives are obtained in the framework of the Wentzel--Kramers--Brillouin approximation. The amount of the variation of the barrier height in the excited channels was estimated accounting the specialization energy which can be interpreted as the excess of the energy of a nucleon with a given spin over the energy for the same spin nucleon state of lowest energy. It is evidenced that the fine structure of cluster decay is due to two competitive effects: the Landau--Zener effect which enhances the probability to have an excited daughter in the final channel and the specialization energy which increases the potential barrier and therefore leads to a diminution of the penetrability. This formalism was used for predictions of the fine structure in the case of 14 C decay of 225 Ac and to explain the fine structure of alpha decay. (author)

Field enhancement due to anomalous skin effect inside a target

International Nuclear Information System (INIS)

Ma, G.; Tan, W.

1996-01-01

A new method based on Fourier transformation to study the skin effects is presented. Using this method, the field amplitude in plasma is represented in terms of electric conductivity, and the normal and anomalous skin effects are described through one formula by omitting the plasma dispersion or not. The results are in agreement with other publications [e.g., J. P. Matte and K. Aguenaou, Phys. Rev. A 45, 2558 (1992)] for equivalent parameters. But for deeper positions inside a target, which have not been studied by others, it is found that the field amplitude is considerably enhanced due to an anomalous skin effect, even for constant collision frequency. In addition, the skin absorptions and some calculations on an anomalous skin effect for different collision frequencies are also presented. copyright 1996 American Institute of Physics

Brain structural plasticity with spaceflight

OpenAIRE

Koppelmans, Vincent; Bloomberg, Jacob J; Mulavara, Ajitkumar P; Seidler, Rachael D

2016-01-01

Humans undergo extensive sensorimotor adaptation during spaceflight due to altered vestibular inputs and body unloading. No studies have yet evaluated the effects of spaceflight on human brain structure despite the fact that recently reported optic nerve structural changes are hypothesized to occur due to increased intracranial pressure occurring with microgravity. This is the first report on human brain structural changes with spaceflight. We evaluated retrospective longitudinal T2-weighted ...

Team Leader Structuring for Team Effectiveness and Team Learning in Command-and-Control Teams.

Science.gov (United States)

van der Haar, Selma; Koeslag-Kreunen, Mieke; Euwe, Eline; Segers, Mien

2017-04-01

Due to their crucial and highly consequential task, it is of utmost importance to understand the levers leading to effectiveness of multidisciplinary emergency management command-and-control (EMCC) teams. We argue that the formal EMCC team leader needs to initiate structure in the team meetings to support organizing the work as well as facilitate team learning, especially the team learning process of constructive conflict. In a sample of 17 EMCC teams performing a realistic EMCC exercise, including one or two team meetings (28 in sum), we coded the team leader's verbal structuring behaviors (1,704 events), rated constructive conflict by external experts, and rated team effectiveness by field experts. Results show that leaders of effective teams use structuring behaviors more often (except asking procedural questions) but decreasingly over time. They support constructive conflict by clarifying and by making summaries that conclude in a command or decision in a decreasing frequency over time.

Team Leader Structuring for Team Effectiveness and Team Learning in Command-and-Control Teams

Science.gov (United States)

van der Haar, Selma; Koeslag-Kreunen, Mieke; Euwe, Eline; Segers, Mien

2017-01-01

Due to their crucial and highly consequential task, it is of utmost importance to understand the levers leading to effectiveness of multidisciplinary emergency management command-and-control (EMCC) teams. We argue that the formal EMCC team leader needs to initiate structure in the team meetings to support organizing the work as well as facilitate team learning, especially the team learning process of constructive conflict. In a sample of 17 EMCC teams performing a realistic EMCC exercise, including one or two team meetings (28 in sum), we coded the team leader’s verbal structuring behaviors (1,704 events), rated constructive conflict by external experts, and rated team effectiveness by field experts. Results show that leaders of effective teams use structuring behaviors more often (except asking procedural questions) but decreasingly over time. They support constructive conflict by clarifying and by making summaries that conclude in a command or decision in a decreasing frequency over time. PMID:28490856

Microstructural changes of AISI 316L due to structural sensitization and its influence on the fatigue properties

Directory of Open Access Journals (Sweden)

Sylvia Dundeková

2014-11-01

Full Text Available Mechanical and fatigue properties of material are dependent on its microstructure. The microstructure of AISI 316L stainless steel commonly used for the production of medical tools, equipment and implants can be easily influenced by its heat treatment. Microstructural changes and fatigue properties of AISI 316L stainless steel due to the heat treatment consisted of annealing at the temperature of 815°C with the dwell time of 500 hours were analyzed in the present paper. Precipitation of intermetallic phases and carbides was observed as a response of the material to the applied heat treatment. Small negative influence was observed in the case of fatigue region bellow 105 cycles; however the fatigue limit remains unchanged due to the structural sensitization.

Electronic structure, Born effective charges and spontaneous polarization in magnetoelectric gallium ferrite

International Nuclear Information System (INIS)

Roy, Amritendu; Garg, Ashish; Mukherjee, Somdutta; Gupta, Rajeev; Prasad, Rajendra; Auluck, Sushil

2011-01-01

We present a theoretical study of the structure-property correlation in gallium ferrite, based on first-principles calculations followed by a subsequent comparison with experiments. The local spin density approximation (LSDA + U) of the density functional theory has been used to calculate the ground state structure, electronic band structure, density of states and Born effective charges. The calculations reveal that the ground state structure is orthorhombic Pc 2 1 n having A-type antiferromagnetic spin configuration, with lattice parameters matching well with those obtained experimentally. Plots of the partial density of states of constituent ions exhibit noticeable hybridization of Fe 3d, Ga 4s, Ga 4p and O 2p states. However, the calculated charge density and electron localization function show a largely ionic character of the Ga/Fe-O bonds which is also supported by a lack of any significant anomaly in the calculated Born effective charges with respect to the corresponding nominal ionic charges. The calculations show a spontaneous polarization of ∼ 59 μC cm -2 along the b-axis which is largely due to asymmetrically placed Ga1, Fe1, O1, O2 and O6 ions.

Effect of volume and surface charges on discharge structure of glow dielectric barrier discharge

Energy Technology Data Exchange (ETDEWEB)

Xu, Shao-Wei; He, Feng; Wang, Yu; Li, Lulu; Ouyang, Ji-Ting [School of Physics, Beijing Institute of Technology, Beijing 100081 (China)

2013-08-15

The effect of volume and surface charges on the structure of glow dielectric barrier discharge (DBD) has been investigated numerically by using two-dimensional (2D) fluid modeling. The local increase of volume or surface charges induces a kind of activation-inhibition effect, which enhances the local volume discharge and inhibits the discharge in neighborhoods, resulting in non-uniform discharge. The activation-inhibition effect due to the non-uniform volume and/or surface charges depends on the non-uniformity itself and the applied voltage. The activation-inhibition of non-uniform charges has different effects on the volume charges and the accumulated surface charges. The distribution of remaining free charges (seed electrons) in volume at the beginning of voltage pulse plays a key role for the glow DBD structure, resulting in a patterned DBD, when the seed electrons are non-uniform at higher frequency and moderate voltage or uniform DBD, when the seed electrons are uniform at lower frequency or high voltage. The distribution of surface charges is not the determining factor but a result of the formed DBD structure.

Effect of soil–structure interaction on the reliability of reinforced concrete bridges

OpenAIRE

Kamel Bezih; Alaa Chateauneuf; Mahdi Kalla; Claude Bacconnet

2015-01-01

In the design of reinforced concrete (RC) bridges, the random and nonlinear behavior of soil may lead to insufficient reliability levels. For this reason, it is necessary to take into account the variability of soil properties which can significantly affect the bridge behavior regarding ultimate and serviceability limit states. This study investigates the failure probability for existing reinforced concrete bridges due to the effects of interaction between the soil and the structure. In this ...

Polymer physics predicts the effects of structural variants on chromatin architecture.

Science.gov (United States)

Bianco, Simona; Lupiáñez, Darío G; Chiariello, Andrea M; Annunziatella, Carlo; Kraft, Katerina; Schöpflin, Robert; Wittler, Lars; Andrey, Guillaume; Vingron, Martin; Pombo, Ana; Mundlos, Stefan; Nicodemi, Mario

2018-05-01

Structural variants (SVs) can result in changes in gene expression due to abnormal chromatin folding and cause disease. However, the prediction of such effects remains a challenge. Here we present a polymer-physics-based approach (PRISMR) to model 3D chromatin folding and to predict enhancer-promoter contacts. PRISMR predicts higher-order chromatin structure from genome-wide chromosome conformation capture (Hi-C) data. Using the EPHA4 locus as a model, the effects of pathogenic SVs are predicted in silico and compared to Hi-C data generated from mouse limb buds and patient-derived fibroblasts. PRISMR deconvolves the folding complexity of the EPHA4 locus and identifies SV-induced ectopic contacts and alterations of 3D genome organization in homozygous or heterozygous states. We show that SVs can reconfigure topologically associating domains, thereby producing extensive rewiring of regulatory interactions and causing disease by gene misexpression. PRISMR can be used to predict interactions in silico, thereby providing a tool for analyzing the disease-causing potential of SVs.

Effects on vegetable seeds due to non ionizing radiation

Energy Technology Data Exchange (ETDEWEB)

Acri, G.; Oliva, A.; Falcone, G. [Universita della Calabria, Dipt. di Fisica, Cosenza (Italy); Acri, G.; Testagrossa, B.; Vermiglio, G.; Tripepi, M.G. [Universita della Calabria, Dipt. di Ecologia, Cosenza (Italy); Bitonti, M.B.; Chiappetta, A. [Universita di Messina, Dipt. di Protezionistica Ambientale, Sanitaria, Sociale ed Industriale, Messina (Italy)

2006-07-01

Based on the tightly relationship between light and plants growth and development, the present work aims to obtain some further insight into the effects of non ionizing radiation the photo-autotrophic organisms, due to the relevant implications for both scientific knowledge and economical and social effects. In this context, a set of experiments was conducted to investigate the influence of a long-lasting exposition to both RF at 1850 MHz and polarized light source on roots elongation of corn kernels. The radical apparatus was chosen as a sensible parameter and the elongation of the roots was monitored as a function of time. Mitotic index and length of meta-xylem cells were estimated in root apex as an index of cell proliferation and cell expansion activity, respectively. (N.C.)

Effects on vegetable seeds due to non ionizing radiation

International Nuclear Information System (INIS)

Acri, G.; Oliva, A.; Falcone, G.; Acri, G.; Testagrossa, B.; Vermiglio, G.; Tripepi, M.G.; Bitonti, M.B.; Chiappetta, A.

2006-01-01

Based on the tightly relationship between light and plants growth and development, the present work aims to obtain some further insight into the effects of non ionizing radiation the photo-autotrophic organisms, due to the relevant implications for both scientific knowledge and economical and social effects. In this context, a set of experiments was conducted to investigate the influence of a long-lasting exposition to both RF at 1850 MHz and polarized light source on roots elongation of corn kernels. The radical apparatus was chosen as a sensible parameter and the elongation of the roots was monitored as a function of time. Mitotic index and length of meta-xylem cells were estimated in root apex as an index of cell proliferation and cell expansion activity, respectively. (N.C.)

Analysis of an Underground Structure Settlement Risk due to Tunneling

DEFF Research Database (Denmark)

Vahdatirad, Mohammad Javad; Ghodrat, Hadi; Firouzianbandpey, Sarah

2010-01-01

of the underground commercial center structure settlement is estimated using both empirical and numerical methods. The settlement risk level of the commercial center structure is determined based on presented definitions about risk classification of various types of structures. Consequently, tunneling processes...

Radiochemical separation and effective dose estimation due to ingestion of 90Sr

International Nuclear Information System (INIS)

Ilic, Z.; Vidic, A.; Deljkic, D.; Sirko, D.; Zovko, E.; Samek, D.

2009-01-01

Since 2007. Institute for Public Health of Federation of Bosnia and Herzegovina-Radiation Protection Centre, within the framework of monitoring of radioactivity of environment carried out measurement of specific activity of 90 Sr content in selected food and water samples. The paper described the methods of measurement and radiochemical separation. Presented results, as average values of specific activity of 90 Sr, were used for estimation of effective dose due to ingestion of 90 Sr for 2007. and 2008. Estimated effective dose for 2007. due to ingestion of 90 Sr for adults was 1,36 μSv and 2,03 μSv for children (10 year old), and for 2008. 0,67 μSv (adults) and 1,01 μSv (children 10 year old). Estimated effective doses for 2007. and 2008. are varied because of different average specific activity radionuclide 90 Sr in selected samples of food, their number, species and origin. (author) [sr

Global earthquake casualties due to secondary effects: A quantitative analysis for improving rapid loss analyses

Science.gov (United States)

Marano, K.D.; Wald, D.J.; Allen, T.I.

2010-01-01

This study presents a quantitative and geospatial description of global losses due to earthquake-induced secondary effects, including landslide, liquefaction, tsunami, and fire for events during the past 40 years. These processes are of great importance to the US Geological Survey's (USGS) Prompt Assessment of Global Earthquakes for Response (PAGER) system, which is currently being developed to deliver rapid earthquake impact and loss assessments following large/significant global earthquakes. An important question is how dominant are losses due to secondary effects (and under what conditions, and in which regions)? Thus, which of these effects should receive higher priority research efforts in order to enhance PAGER's overall assessment of earthquakes losses and alerting for the likelihood of secondary impacts? We find that while 21.5% of fatal earthquakes have deaths due to secondary (non-shaking) causes, only rarely are secondary effects the main cause of fatalities. The recent 2004 Great Sumatra-Andaman Islands earthquake is a notable exception, with extraordinary losses due to tsunami. The potential for secondary hazards varies greatly, and systematically, due to regional geologic and geomorphic conditions. Based on our findings, we have built country-specific disclaimers for PAGER that address potential for each hazard (Earle et al., Proceedings of the 14th World Conference of the Earthquake Engineering, Beijing, China, 2008). We will now focus on ways to model casualties from secondary effects based on their relative importance as well as their general predictability. ?? Springer Science+Business Media B.V. 2009.

Development of Program Evaluating the Effects on the Secondary Side of Steam Generator due to Foreign Objects

International Nuclear Information System (INIS)

Ju, Yoo Hyun; Nam, Choi Sung

2005-01-01

When materials such as metal are into the secondary side of steam generator, they, so called foreign objects, may have influences on the integrity of the steam generator tubes. They cause the tube wear due to the relative motion between the tubes and foreign objects and the tube impact due to flow. The best way to avoid the effects is to remove all the foreign objects. However, it is not easy to remove the foreign materials thoroughly due to their condition such as the location. If the locations of the foreign materials are in the middle of tube bundle and the tube arrangement of the steam generator is the triangle type, the equipment such as FOSAR(Foreign Object Search and Retrieval) can not reach their locations. If the foreign materials stick together with the tubes or tube sheet, they can not be removed. In the case of operating the steam generator with the foreign materials, the licensee must prove that the materials do not affect the tube integrity and do not threaten the pressure boundary with the analytical method. Considering the wear and impact by the foreign materials, KEPRI(Korea Electric Power Research Institute) developed the methodology to evaluate the foreign materials analytically. This methodology was described with a computer program in order to obtain the fast results. The program informs whether the tubes have the structural integrity when the foreign material strikes the tubes. Moreover, this gives us the remaining life of the steam generator tubes. In this paper, the program, which evaluates the effects of the foreign objects in the secondary side of steam generator, is introduced

Effects of confinement and external fields on structure and transport in colloidal dispersions in reduced dimensionality

International Nuclear Information System (INIS)

Wilms, D; Virnau, P; Binder, K; Deutschländer, S; Siems, U; Franzrahe, K; Henseler, P; Keim, P; Schwierz, N; Maret, G; Nielaba, P

2012-01-01

In this work, we focus on low-dimensional colloidal model systems, via simulation studies and also some complementary experiments, in order to elucidate the interplay between phase behavior, geometric structures and transport properties. In particular, we try to investigate the (nonlinear!) response of these very soft colloidal systems to various perturbations: uniform and uniaxial pressure, laser fields, shear due to moving boundaries and randomly quenched disorder. We study ordering phenomena on surfaces or in monolayers by Monte Carlo computer simulations of binary hard-disk mixtures, the influence of a substrate being modeled by an external potential. Weak external fields allow a controlled tuning of the miscibility of the mixture. We discuss the laser induced de-mixing for the three different possible couplings to the external potential. The structural behavior of hard spheres interacting with repulsive screened Coulomb or dipolar interaction in 2D and 3D narrow constrictions is investigated using Brownian dynamics simulations. Due to misfits between multiples of the lattice parameter and the channel widths, a variety of ordered and disordered lattice structures have been observed. The resulting local lattice structures and defect probabilities are studied for various cross sections. The influence of a self-organized order within the system is reflected in the velocity of the particles and their diffusive behavior. Additionally, in an experimental system of dipolar colloidal particles confined by gravity on a solid substrate we investigate the effect of pinning on the dynamics of a two-dimensional colloidal liquid. This work contains sections reviewing previous work by the authors as well as new, unpublished results. Among the latter are detailed studies of the phase boundaries of the de-mixing regime in binary systems in external light fields, configurations for shear induced effects at structured walls, studies on the effect of confinement on the structures

Study of electro-optic effect in asymmetrically ramped AlInGaAs multiple quantum well structures

Energy Technology Data Exchange (ETDEWEB)

Sadiq, Muhammad Usman; Peters, Frank H.; Corbett, Brian [Tyndall National Institute, Lee Maltings, Cork (Ireland); Department of Physics, University College Cork, Cork (Ireland); O' Callaghan, James; Roycroft, Brendan; Thomas, Kevin; Pelucchi, Emanuele [Tyndall National Institute, Lee Maltings, Cork (Ireland)

2016-04-15

We investigate the electro-optic properties of two oppositely ramped asymmetric quantum well structures in the AlInGaAs material system. The grading of the bandgap in the quantum wells has been achieved by changing the ratio of Al to Ga in the quaternary alloy during the epitaxial growth. The surface normal photo-response and the Fabry-Perot fringe shift in straight waveguides are compared for both structures as a function of applied voltage at 1550 nm for TE-polarized light. The measurements show a change in the refractive index due to a red shift of the excitonic resonances due to the quantum-confined Stark effect. The 10 quantum well structure with a ramp up of the bandgap in the growth direction leads to the figure of merit of the voltage for a π phase shift, V{sub π} by length, L, V{sub π} x L, of 6 as compared to 7 V . mm in the structure with a ramp in opposite direction. Further investigations show that the reduction in V{sub π} is due to increased absorption at high reverse bias which induces a non-linear phase change. (copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Estimation of health effects due to elevated radiation exposure levels in structures

International Nuclear Information System (INIS)

Marks, S.; Cross, F.T.; Denham, D.H.; Kennedy, W.E. Jr.

1985-02-01

Uranium mill tailings were used as landfill for many years in the United States before the health risk associated with such use was recognized. Occupants of buildings erected on or adjacent to contaminated landfills may experience radiation exposures sufficient to warrant remedial action. Estimates of the cost-effectiveness of the remedial measures may be provided using a combination of occupancy data, appropriate risk coefficients and projected costs. This effort is in support of decisions by the US Department of Energy (DOE) to conduct remedial action at such locations. The methods used in this project, with examples of their application, will be presented in this paper

Structure effect on the interaction of phenylurea herbicides with model biomembrane as an environmental mobility parameter.

Science.gov (United States)

Librando, Vito; Forte, Stefano; Sarpietro, Maria G

2004-01-15

During recent years, intensive use of herbicides has raised increasing concern mainly due to their massive pollution of the environment. As these herbicides are directly or indirectly toxic to a wide range of organisms, their potential for contaminating soil, surface water, and groundwater makes these xenobiotics of special interest from a health and environmental point of view. Knowledge of the mechanisms by which they exert their toxic effects is becoming a need. Because of the herbicides' lipophilicity, a possible site of interaction in the cell is represented by biomembranes. The interaction of four herbicides, difenoxuron, diuron, linuron, and metoxuron, with model membranes constituted of dimyristoylphosphatidylcholine multilamellar vesicles was investigated by the differential scanning calorimetry technique. The aim was to study the effects exerted by an increasing amount of the examined compounds on thermotropic behavior of the model phospholipid membranes and to correlate the obtained results with structural features of the herbicides due to their environmental mobility. Among the herbicides studied, linuron is the most effective in perturbing the ordinate structure of vesicles forming phospholipids, whereas metoxuron is the least effective and the others exert an intermediate effect. Linuron exerts its effect both on the transition temperature of the gel to the liquid crystalline phase and on the enthalpy change. Difenoxuron, diuron, and metoxuron cause a change in the transition temperature but have an insignificant effect on the enthalpy change. The calorimetric results, correlated with the structural features of the herbicides, are consistent with their partition coefficient, log K(ow), suggesting that the more hydrophobic compound character causes a greater liposolubility and consequential cellular absorption with more effectiveness on the membrane order.

Assessing the indirect effects due to natural hazards on a mesoscale

Science.gov (United States)

Pfurtscheller, C.; Schwarze, R.

2009-04-01

Measuring indirect economic costs and other effects from natural hazards, especially floods in alpine and other mountainous regions, are a necessary part of a comprehensive economic assessment. Their omission seriously affects the relative economic benefits of structural or non structural measures of flood defence. Surpassing controversial, IO-model-based economic estimates, analysing indirect economic effects lead to the key question of identifying and evaluating the drivers of indirect economic effects and resilience to system effects in the regional economy, i.e. at the meso-level. This investigation takes place for the catastrophic floods in summer 2005 in the provinces of Tyrol and Vorarlberg, Austria, which caused an estimated € 670 Mio direct loss on private and public assets and severe interruptions in lifeline services. The paper starts out with differentiating the concept of indirect economic costs from direct costs, examing different temporal (short vs. long-term) and spatial (macro-, meso- vs. microeconomic) system boundaries. It surveys common theories of economic resilience and vulnerability at the regional economy level. Indirect effects at the regional economy level can be defined as interferences of the economic exchange of goods and services triggered by breakdowns of transport lines and critical production inputs. The extent and persistence of indirect effects of natural hazards is not only by parameters of the extreme event, such as duration and amplitude of the flood, but much more by resilience parameters of the regional economy such as size of enterprises, the network structure (linkages) of the regional economy, availability of insurance and relief funds, and the stock of inventory. These effects can only be dissected by means of expert judgement and event studies. This paper presents the results of a survey conducted among business practioneers, members of chamber of commerce, civil protection agencies to identify and scale the drivers of

Fluorescence, Decay Time, and Structural Change of Laser Dye Cresyl Violet in Solution due to Microwave Irradiation at GSM 900/1800 Mobile Phone Frequencies

Directory of Open Access Journals (Sweden)

Fuat Bayrakceken

2012-01-01

Full Text Available Microwave irradiation at GSM 900/1800 MHz mobile phone frequencies affects the electronic structure of cresyl violet in solution. These changes are important because laser-dye cresyl violet strongly bonds to DNA- and RNA-rich cell compounds in nerve tissues. The irradiation effects on the electronic structure of cresyl violet and its fluorescence data were all obtained experimentally at room temperature. For most laser dyes, this is not a trivial task because laser dye molecules possess a relatively complex structure. They usually consist of an extended system of conjugated double or aromatic π-bonds with attached auxochromic (electron donating groups shifting the absorption band further towards longer wavelength. Because of the intrinsically high degree of conjugation, the vibrational modes of the molecular units couple strongly with each other. We found that the fluorescence quantum yield was increased from to due to intramolecular energy hopping of cresyl violet in solution which is exposed to microwave irradiation at mobile phone frequencies, and the photonic product cannot be used as a laser dye anymore.

Infrared absorption, multiphonon processes and time reversal effect on Si and Ge band structure

International Nuclear Information System (INIS)

Kunert, H.W.; Machatine, A.G.J.; Malherbe, J.B.; Barnas, J.; Hoffmann, A.; Wagner, M.R.

2008-01-01

We have examined the effect of Time Reversal Symmetry (TRS) on vibrational modes and on the electronic band structure of Si and Ge. Most of the primary non-interacting modes are not affected by TRS. Only phonons originating from high symmetry lines S and A of the Brillouin Zone (BZ) indicate extra degeneracy. Selection rules for some two and three phonons originating from high symmetry lines are determined. The states of electrons and holes described by electronic band structure due to spin-inclusion are assigned by spinor representations of the double space group. Inclusion of the TRS into the band structure results in extra degeneracy of electrons and holes, and therefore optical selection rules suppose to be modified

The effects of 7-dehydrocholesterol on the structural properties of membranes

Science.gov (United States)

Liu, Yingzhe; Chipot, Christophe; Shao, Xueguang; Cai, Wensheng

2011-10-01

Smith-Lemli-Opitz syndrome, a congenital and developmental malformation disease, is typified by abnormal accumulation of 7-dehydrocholesterol (7DHC), the immediate precursor of cholesterol (CHOL), and depletion thereof. Knowledge of the effect of 7DHC on the biological membrane is, however, still fragmentary. In this study, large-scale atomistic molecular dynamics simulations, employing two distinct force fields, have been conducted to elucidate differences in the structural properties of a hydrated dimyristoylphosphatidylcholine bilayer due to CHOL and 7DHC. The present series of results indicate that CHOL and 7DHC possess virtually the same ability to condense and order membranes. Furthermore, the condensing and ordering effects are shown to be strengthened at increasing sterol concentrations.

The effect of a loss of model structural detail due to network skeletonization on contamination warning system design: case studies

Science.gov (United States)

Davis, Michael J.; Janke, Robert

2018-05-01

The effect of limitations in the structural detail available in a network model on contamination warning system (CWS) design was examined in case studies using the original and skeletonized network models for two water distribution systems (WDSs). The skeletonized models were used as proxies for incomplete network models. CWS designs were developed by optimizing sensor placements for worst-case and mean-case contamination events. Designs developed using the skeletonized network models were transplanted into the original network model for evaluation. CWS performance was defined as the number of people who ingest more than some quantity of a contaminant in tap water before the CWS detects the presence of contamination. Lack of structural detail in a network model can result in CWS designs that (1) provide considerably less protection against worst-case contamination events than that obtained when a more complete network model is available and (2) yield substantial underestimates of the consequences associated with a contamination event. Nevertheless, CWSs developed using skeletonized network models can provide useful reductions in consequences for contaminants whose effects are not localized near the injection location. Mean-case designs can yield worst-case performances similar to those for worst-case designs when there is uncertainty in the network model. Improvements in network models for WDSs have the potential to yield significant improvements in CWS designs as well as more realistic evaluations of those designs. Although such improvements would be expected to yield improved CWS performance, the expected improvements in CWS performance have not been quantified previously. The results presented here should be useful to those responsible for the design or implementation of CWSs, particularly managers and engineers in water utilities, and encourage the development of improved network models.

Shielding effect of snow cover on indoor exposure due to terrestrial gamma radiation

International Nuclear Information System (INIS)

Fujimoto, Kenzo; Kobayashi, Sadayoshi

1988-01-01

Many people in the world live in high latitude region where it snows frequently in winter. When snow covers the ground, it considerably reduces the external exposure from the radiation sources in the ground. Therefore, the evaluation of snow effect on exposure due to terrestrial gamma radiation is necessary to obtain the population dose as well as the absorbed dose in air in snowy regions. Especially the shielding effect on indoor exposure is essentially important in the assessment of population dose since most individuals spend a large portion of their time indoors. The snow effect, however, has been rather neglected or assumed to be the same both indoors and outdoors in the population dose calculation. Snow has been recognized only as a cause of temporal variation of outdoor exposure rate due firstly to radon daughters deposition with snow fall and secondly to the shielding effect of snow cover. This paper describes an approach to the evaluation of shielding effect of snow cover on exposure and introduces population dose calculation as numerical example for the people who live in wooden houses in Japan

Structural and effective connectivity in focal epilepsy

Directory of Open Access Journals (Sweden)

Christopher S. Parker

2018-01-01

Full Text Available Patients with medically-refractory focal epilepsy may be candidates for neurosurgery and some may require placement of intracranial EEG electrodes to localise seizure onset. Assessing cerebral responses to single pulse electrical stimulation (SPES may give diagnostically useful data. SPES produces cortico-cortical evoked potentials (CCEPs, which infer effective brain connectivity. Diffusion-weighted images and tractography may be used to estimate structural brain connectivity. This combination provides the opportunity to observe seizure onset and its propagation throughout the brain, spreading contiguously along the cortex explored with electrodes, or non-contiguously. We analysed CCEPs and diffusion tractography in seven focal epilepsy patients and reconstructed the effective and structural brain networks. We aimed to assess the inter-modal similarity of the networks at a large scale across the cortex, the effective and structural connectivity of the ictal-onset zone, and investigate potential mechanisms of non-contiguous seizure spread. We found a significant overlap between structural and effective networks. Effective network CCEP amplitude, baseline variation, and outward connectivity was higher at ictal-onset zones, while structural connection strength within the ictal-onset zone tended to be higher. These findings support the concept of hyperexcitable cortex being associated with seizure generation. The high prevalence of structural and effective connections from the ictal-onset zone to sites of non-contiguous spread suggests that macroscopic structural and effective connections are plausible routes for non-contiguous seizure spread.

Effect of Additional Structure on Effective Stack Height of Gas Dispersion in Atmosphere

Directory of Open Access Journals (Sweden)

Takenobu Michioka

2016-03-01

Full Text Available Wind-tunnel experiments were conducted to evaluate the effect of additional structure (building, sea wall and banking on the effective stack height, which is usually used in safety analyses of nuclear power facilities in Japan. The effective stack heights were estimated with and without the additional structure in addition to the reactor building while varying several conditions such as the source height, the height of additional structure and the distance between the source position and the additional structure. When the source height is equivalent to the reactor building height, the additional structure enhances both the vertical and horizontal gas dispersion widths and decreases the ground gas concentration, and it means that the additional structure does not decrease the effective stack height. When the source height is larger than the reactor height, the additional structures might affect the effective stack height. As the distance between the source and the additional structure decreases, or as the height of the additional structure increases, the structure has a larger effect on the effective stack height.

Some considerations on the dynamic structure-soil-structure interactions analysis

International Nuclear Information System (INIS)

Matthees, W.

1979-01-01

A mixed method has been developed for the approximate analysis of soil-structure or structure-soil-structure interaction problems due to earthquakes. In order to produce comparable results of interaction problems as well as for shallow and for deep soils due to the same earthquake excitation (accelerogram) situated always at the lower bedrock boundary, the analysis is performed in two steps: 1) Calculation of the complex transfer function and the response of the upper interior boundary of a layered soil-system which is connected at its top to a soil-structure-system, using the one-dimensional deconvolution. 2) By making a complete interaction analysis of the surface soil-structure-system using the interior boundary excitation of the calculated response from step 1. The depth of the soil-structure-system must be chosen large enough to exclude interaction effects down to the layered soil-system's interior boundary. (orig.)

Si/Ge hetero-structure nanotube tunnel field effect transistor

KAUST Repository

Hanna, A. N.

2015-01-07

We discuss the physics of conventional channel material (silicon/germanium hetero-structure) based transistor topology mainly core/shell (inner/outer) gated nanotube vs. gate-all-around nanowire architecture for tunnel field effect transistor application. We show that nanotube topology can result in higher performance through higher normalized current when compared to nanowire architecture at Vdd-=-1-V due to the availability of larger tunneling cross section and lower Shockley-Reed-Hall recombination. Both architectures are able to achieve sub 60-mV/dec performance for more than five orders of magnitude of drain current. This enables the nanotube configuration achieving performance same as the nanowire architecture even when Vdd is scaled down to 0.5-V.

Si/Ge hetero-structure nanotube tunnel field effect transistor

KAUST Repository

Hanna, A. N.; Hussain, Muhammad Mustafa

2015-01-01

We discuss the physics of conventional channel material (silicon/germanium hetero-structure) based transistor topology mainly core/shell (inner/outer) gated nanotube vs. gate-all-around nanowire architecture for tunnel field effect transistor application. We show that nanotube topology can result in higher performance through higher normalized current when compared to nanowire architecture at Vdd-=-1-V due to the availability of larger tunneling cross section and lower Shockley-Reed-Hall recombination. Both architectures are able to achieve sub 60-mV/dec performance for more than five orders of magnitude of drain current. This enables the nanotube configuration achieving performance same as the nanowire architecture even when Vdd is scaled down to 0.5-V.

Kinetic, volumetric and structural effects induced by liquid Ga penetration into ultrafine grained Al

International Nuclear Information System (INIS)

Naderi, Mehrnoosh; Peterlechner, Martin; Schafler, Erhard; Divinski, Sergiy V.; Wilde, Gerhard

2015-01-01

Kinetic, volumetric and structural effects induced by penetration of liquid Ga in ultrafine grained (UFG) Al produced by severe plastic deformation using high-pressure torsion were studied by isothermal dilatometric measurements, electron microscopy, atomic force microscopy and X-ray diffraction. Severe plastic deformation changed the distribution of impurities and their segregation was revealed by transmission electron microscopy. Two-stage length changes of UFG Al were observed which are explained by counteracting effects of expansion due to grain boundary segregation of Ga and contraction due to precipitation and recrystallization. After applying Ga, the kinetics of the liquid Ga penetration in UFG Al is studied in-situ in the electron microscope by the “first appearance” method and the time scales are in agreement with those inducing the volumetric changes

Ionochromic effects and structures of metalated poly(p-phenylenevinylene) polymers incorporating 2,2'-bipyridines

International Nuclear Information System (INIS)

Chen, L.X.; Jager, W.J.H.; Gosztola, D.J.; Niemczyk, M.P.; Wasielewski, M.R.

2000-01-01

The effects of metal ion chelation to the 2,2'-bipyridine (bpy) groups on the photophysics and exciton dynamics of two conjugated polymers 1 and 2 in solution are investigated. The structures of polymers 1 and 2 have 2,2'-bipyridyl-5-vinylene units that alternate with one and three 2,5-bis(n-decyloxy)-1,4-phenylenevinylene monomer units, respectively. The photophysics and exciton dynamics of metalated polymers 1 and 2 are compared to those of the metal-free polymers (Chen et al. J. Phys. Chem. A 1999, 103, 4341-4351). The origins of ionochromic effects due the metal ion chelation were studied using both steady-state and transient optical spectroscopy, and the results indicate that both conformational flattening and participation of Jr electrons from the metal in the π-conjugation of the polymer backbone play important roles in metal ion binding induced red shifts in absorption and photoluminescence spectra. The photoluminescence properties of the metalated polymers are determined by the metal ion electronic structures, where the closed shell Zn 2+ -bound polymer 2 has an increased photoluminescence quantum yield and the corresponding open shell Ni 2+ - or Fe 3+ -bound polymers have quenched photoluminescence due to spin-orbit coupling. The dual character of metalated polymer 2 as a conjugated polymer and as a metal-bpy complex is discussed. In addition, the structures of metal ion binding sites are studied via X-ray absorption fine structure (XAFS) and are related to the photophysical properties of the metalated polymers

Quark effects in nuclear structure

International Nuclear Information System (INIS)

Watt, A.

1987-01-01

Some experimental data in nuclear structure physics cannot be explained on the assumption that nuclei consist of inert protons and neutrons. The quark model attributes a definite internal structure to nucleons and implies that their properties should change when embedded in a nucleus. This article reviews some of the experimental evidence for these effects and discusses some new aspects of nuclear structure predicted by the quark model

Blending protocol effect in structural properties of PA6/ABS nanocomposites compatibilized with SAN-MA

International Nuclear Information System (INIS)

Castro, Lucas D.C. de; Oliveira, Amanda D.; Pessan, Luiz Antonio

2015-01-01

Nanocomposites based on polyamide 6 (PA6) and acrylonitrile-butadiene-styrene (ABS) compatibilized with styrene acrylonitrile-co-maleic anhydride were prepared using different blending protocols in a twin screw extruder. Specimen were prepared though injection molding. The organoclay (OMMT) incorporation and blending sequence effect on structural properties were investigated. X-ray diffraction analysis (XRD) indicates a complete exfoliated structure for all samples. Rheological measurements show an increasing in nanocomposites complex viscosities and storage modulus values when compared with the ternary blend. However, no significant effects in the rheological behavior were observed due the blending sequence. Differential scanning calorimetry (DSC) measurements suggests the incorporation of OMMT and different blending protocols may influence the polyamide polymorphism and degree of crystallinity. (author)

Generation and maintenance of low effective pressures due to fluid flow in fractured rocks

Science.gov (United States)

Garagash, D.; Brantut, N.; Schubnel, A.; Bhat, H. S.

2017-12-01

The pore fluid pressure is expected to increase with increasing depth in the crust, primarily due to gravity forces. Because direct measurements are impossible beyond a few kilometers depths, the pore pressure gradient is often assumed to be linear (e.g., hydrostatic). However, a number of processes can severely modify the fluid pressure distribution in the crust. Here, we investigate the effect of fluid flow coupled to nonlinear permeability-effective pressure relationship. We performed a set of laboratory fluid flow experiments on thermally cracked Westerly granite at confining pressures up to 200 MPa and pore fluid pressures up to 120 MPa. Fluid flow was generated by imposing very strong pore pressure differences, up to 120 MPa, between the ends of the sample. The vertical fluid pressure distribution inside the sample was inferred by a set of 8 radial strain gauges, and an array of 10 P- and S-wave transducers. When the effective stress is kept near zero at one end of the sample and maintained high at the other end, the steady-state pore pressure profile is nonlinear. The effective stress, as inferred from the strain gauge array, remains close to zero through 2/3 of the sample, and increases sharply near the drained end of the sample. The ultrasonic data are used to build a vertical P- and S-wave velocity structure. The wave velocity profiles are consistent with a nonlinear relationship between wave velocity and effective pressure, as expected in thermally cracked granite. Taken together, our experimental data confirm the theoretical prediction that near zero effective stress can be generated through significant sections of rocks as a response to an imposed fluid flow. This has strong implications for the state of stress of the Earth's crust, especially around major continental transform faults that act as conduits for deep volatiles.

Structural analysis of an underground reinforced concrete waste storage tank due to over-pressurization

International Nuclear Information System (INIS)

Xu, J.; Bandyopadhyay, K.; Shteyngart, S.

1993-01-01

This paper presents the results of a structural analysis performed by use of the finite element method in determining the pressure-carrying capacity of an underground tank which contains nuclear wastes. The tank and surrounding soil were modeled and analyzed using the ABAQUS program. Special emphasis as given to determining the effects of soil-containment interaction by employing a Coulomb friction model. The effect of material properties was investigated by considering two sets of stress-strain data for the steel plates. In addition, a refined mesh was used to evaluate the strain concentration effects at steel liner thickness discontinuities

Nonlinear soil-structure interaction due to base slab uplift on the seismic response of an HTGR plant

International Nuclear Information System (INIS)

Kennedy, R.P.; Short, S.A.; Wesley, D.A.; Lee, T.H.

1975-01-01

The importance of the nonlinear soil-structure interaction effects resulting from substantial base slab uplift occurring during a seismic excitation are evaluated. The structure considered consisted of the containment building and prestressed concrete reactor vessel for a typical HTGR plant. A simplified dynamic mathematical model was utilized consisting of a conventional lumped mass structure with soil-structure interaction accounted for by translational and rotational springs whose properties are determined by elastic half space theory. Three different site soil conditions (a rock site, a moderately stiff soil and a soft soil site) and two levels of horizontal ground motion (0.3g and 0.5g earthquakes) were considered. It may be concluded that linear analysis can be used to conservatively estimate the important behavior of the base slab, even under conditions of substantial base slab uplift. For all cases investigated, linear analysis resulted in higher base overturning moments, greater toe pressures, and greater heel uplift distances than nonlinear analyses. It may also be concluded that the nonlinear effect of uplift does not result in any significant lengthening of the fundamental period of the structure. Also, except in the short period region only negligible differences exist between instructure response spectra based on linear analysis and those based on nonlinear analysis. Finally, for sites in which soil-structure interaction is not significant, as for the rock site, the peak structural response at all locations above the base mat are not significantly influenced by the nonlinear effects of base slab uplift. However, for the two soil sites, the peak shears and moments are, in a few instances, significantly different between linear and nonlinear analyses

Effect of structural inheritance on effectiveness of 'intercritical quenching'

International Nuclear Information System (INIS)

Kut'in, A.B.; Polyakova, A.M.; Gerbikh, N.M.

1989-01-01

Effect of quenching from intercritical interval on tempering brittleness suppression by comparing structural changes under heating of steels which do not tend to structural inheritance and steels, additionally doped with elements increasing the tendency of preliminary quenching grain to reduction, is studied. Investigation was conducted using medium-carbon chromium nickel steels, melted in an open induction furnace. It is shown that effect of quenching from intercritical interval on the tempering brittleness attennuation is increased with the increase of steel tendency to structural inheritance. Intergranular embrittlement suppression at tempering is obviously caused by a uniform distribution of impurities on subboundaries in the grain volume

The effects of local correlations on the electronic structure of FeSe

Science.gov (United States)

Watson, Matthew; Kim, Timur; Haghighirad, Amir; Coldea, Amalia

FeSe is structurally the simplest of Fe-based superconductors, but its complex and unique properties pose important theoretical questions. One important aspect of the physics of FeSe is the understanding of the strength and effects of electronic correlations. In order to explore this, we have performed angle-resolved photo-emission spectroscopy (ARPES) measurements on high quality bulk single crystals of FeSe over a wide range of binding energies, in different scattering geometries and with varying incident photon energies, analysing the quasiparticle renormalisations, scattering rates and degree of coherence. We find that FeSe exhibits moderately strong, orbital-dependent correlation effects which are understood to arise primarily due to local electron-electron interactions on the Fe sites. We conclude that electronic correlations constitute a key ingredient in understanding the electronic structure of FeSe. Part of this work was supported by EPSRC, UK (EP/I004475/1, EP/I017836/1). We thank Diamond Light Source for access to Beamline I05.

Effective constraint algebras with structure functions

International Nuclear Information System (INIS)

Bojowald, Martin; Brahma, Suddhasattwa

2016-01-01

This article presents the result that fluctuations and higher moments of a state, by themselves, do not imply quantum corrections in structure functions of constrained systems. Moment corrections are isolated from other types of quantum effects, such as factor-ordering choices and regularization, by introducing a new condition with two parts: (i) having a direct (or faithful) quantization of the classical structure functions, (ii) free of factor-ordering ambiguities. In particular, it is assumed that the classical constraints can be quantized in an anomaly free way, so that properties of the resulting constraint algebras can be derived. If the two-part condition is not satisfied, effective constraints can still be evaluated, but quantum effects may be stronger. Consequences for canonical quantum gravity, whose structure functions encode space–time structure, are discussed. In particular, deformed algebras found in models of loop quantum gravity provide reliable information even in the Planck regime. (paper)

On the sea-covering effect of a huge floating structure on the surrounding water; Choogata futai shuhen no kaisui ni taisuru kaimen shahei no eikyo ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Fujino, M; Kagemoto, H; Hamada, T [The University of Tokyo, Tokyo (Japan)

1997-12-31

The numerical analysis program based on the difference method for dynamics of sea water with sea-surface displacement, flow rate, salt content and temperature as the parameters is modified to more accurately assess the effects of a huge marine structure on surrounding environment by adding the effects of insolation and boundary conditions of the sea-covering effects of the floating structure. The numerical simulation was done for summer and winter seasons, not in a sea area but using a rectangular bay with the floating structure at the center. A new flow evolves around the floating structure, due to the sea-covering effect. The flow patterns in summer and winter are clearly different, due to difference in insolation. The predicted flow is also sensitive whether stratification is considered or not, by which is meant that it is important what stratification effect is taken into account. Daily insolation changes are accompanied by vertical distribution of water temperature and its temporal change. These effects are also observed under the floating structure which shields insolation. 10 refs., 17 figs., 4 tabs.

On the sea-covering effect of a huge floating structure on the surrounding water; Choogata futai shuhen no kaisui ni taisuru kaimen shahei no eikyo ni tsuite

Energy Technology Data Exchange (ETDEWEB)

Fujino, M.; Kagemoto, H.; Hamada, T. [The University of Tokyo, Tokyo (Japan)

1996-12-31

The numerical analysis program based on the difference method for dynamics of sea water with sea-surface displacement, flow rate, salt content and temperature as the parameters is modified to more accurately assess the effects of a huge marine structure on surrounding environment by adding the effects of insolation and boundary conditions of the sea-covering effects of the floating structure. The numerical simulation was done for summer and winter seasons, not in a sea area but using a rectangular bay with the floating structure at the center. A new flow evolves around the floating structure, due to the sea-covering effect. The flow patterns in summer and winter are clearly different, due to difference in insolation. The predicted flow is also sensitive whether stratification is considered or not, by which is meant that it is important what stratification effect is taken into account. Daily insolation changes are accompanied by vertical distribution of water temperature and its temporal change. These effects are also observed under the floating structure which shields insolation. 10 refs., 17 figs., 4 tabs.

Crystallographic changes in lead zirconate titanate due to neutron irradiation

Directory of Open Access Journals (Sweden)

Alexandra Henriques

2014-11-01

Full Text Available Piezoelectric and ferroelectric materials are useful as the active element in non-destructive monitoring devices for high-radiation areas. Here, crystallographic structural refinement (i.e., the Rietveld method is used to quantify the type and extent of structural changes in PbZr0.5Ti0.5O3 after exposure to a 1 MeV equivalent neutron fluence of 1.7 × 1015 neutrons/cm2. The results show a measurable decrease in the occupancy of Pb and O due to irradiation, with O vacancies in the tetragonal phase being created preferentially on one of the two O sites. The results demonstrate a method by which the effects of radiation on crystallographic structure may be investigated.

The ketogenic diet is effective for refractory epilepsy associated with acquired structural epileptic encephalopathy.

Science.gov (United States)

Villaluz, Mel Michel; Lomax, Lysa Boissé; Jadhav, Trupti; Cross, J Helen; Scheffer, Ingrid E

2018-07-01

Ketogenic diet therapies have proven efficacy for refractory epilepsy. There are many reports of their use in the genetic developmental and epileptic encephalopathies; however, little attention has been paid as to whether the diet is also effective in individuals with an acquired structural aetiology. We observed remarkable efficacy of the diet in two patients with hypoxic-ischaemic encephalopathy. We then analysed our cases with refractory structural epilepsies of acquired origin to characterize their response to the ketogenic diet. The classical ketogenic diet was implemented with dietary ratios of 3:1 to 4.4:1. Seizure frequency at 1 month, 3 months, 6 months, 1 year, and 2 years was ascertained. A responder was defined as greater than 50% seizure reduction compared to baseline. Seven of the nine patients were responders at 3 months. Somewhat surprisingly we found that the ketogenic diet was effective in patients with a developmental and epileptic encephalopathy due to an acquired structural aetiology. This cohort may not be routinely considered for the ketogenic diet because of their structural and acquired, rather than genetic, basis. The ketogenic diet should be considered early in the management of patients with acquired structural encephalopathies as it can improve seizure control with the potential to improve developmental outcome. The ketogenic diet was effective in children with epilepsy associated with an acquired structural aetiology. © 2018 Mac Keith Press.

A study on the effects of seawater on the durable life of concrete structures(II)

Energy Technology Data Exchange (ETDEWEB)

Oh, Byung Hwan; Jang, Bong Suk; Jang, Seung Yeop; Jeon, Se Jin; Yu, Yeong; Park, Dae Gyun; Hyeong, Sang Soo [Seoul National Univ., Seoul (Korea, Republic of)

1999-02-15

Recently, large scale concrete structures such as nuclear power plants and offshore structures are actively being built in this country. These structures are subject to heavy attack due to seawater environment. A reasonable consideration for corrosion has not been paid to the structures in the past decades due to insufficient research data and guidelines. The durability is emerging as one of the most important factors. In the design and construction of concrete structures. The purpose of the present study is, therefore, to explore the corrosion mechanism and penetration mechanism of chloride ion, and to establish the evaluation procedure of durability life of concrete structures. In this study, the chloride ion concentration of seawater around our country have been analyzed and the deterioration mechanism of concrete structures have been also analyzed. The penetration mechanism of seawater into the concrete has been also studied. To this end, a comprehensive experimental program has been setup. The major test variables include the type of cement and the type of mineral admixture. The strength test as well as corrosion test have been conducted to explore the effects of chloride ion penetration on the properties of concrete. The corrosion mechanism and the penetration of chloride ion into concrete structures have been studied. These results will allow the estimation of durable life of concrete structures in nuclear power plants. The experimental results and the developed theory in the present study can be efficiently used to analyze the chloride ion penetration and to estimate the durability of concrete structures In nuclear power plants. The present study may also provide strong basis to evaluate the remaining service life of concrete structures in nuclear power plants.

Investigation of the structure change of atomic shells due to uranium ionization by the Dirac-Fock-Slater method

International Nuclear Information System (INIS)

Shchornak, G.

1979-01-01

The influence of outer vacancies in the atomic shells of uranium on the atomic shell structure is claculated by the Dirac-Fock-Slater method. It is found out that the energy of the X-ray transitions increases due to the detachment of the electrons with the lowest binding energies. The electron detachment from the subshells of the 4f level gives rise to negative energy shifts of the X-ray transitions.(author)

Greenhouse effects due to man-made perturbations of trace gases

Science.gov (United States)

Wang, W. C.; Yung, Y. L.; Lacis, A. A.; Mo, T.; Hansen, J. E.

1976-01-01

Nitrous oxide, methane, ammonia, and a number of other trace constituents of the earth's atmosphere have infrared absorption bands in the spectral range from 7 to 14 microns. Despite their small amounts, these gases can have a significant effect on the thermal structure of the atmosphere by transmitting most of the thermal radiation from the earth's surface to the lower atmosphere. In the present paper, this greenhouse effect is computed for a number of trace gases. The nature and climatic implications of possible changes in the concentrations of N2O, CH4, NH3, and HNO3 are discussed.

Effect of biocompatible polymers on the structural integrity of lipid bilayers under external stimuli

Science.gov (United States)

Wang, Jia-Yu; Kausik, Ravinath; Chen, Chi-Yuan; Han, Song-I.; Marks, Jeremy; Lee, Ka Yee

2010-03-01

Cell membrane dysfunction due to loss of structural integrity is the pathology of tissue death in trauma and common diseases. It is now established that certain biocompatible polymers, such as Poloxamer 188, Poloxamine 1107 and polyethylene glycol (PEG), are effective in sealing of injured cell membranes, and able to prevent acute necrosis. Despite these broad applications of these polymers for human health, the fundamental mechanisms by which these polymers interact with cell membranes are still under debate. Here, the effects of a group of biocompatible polymers on phospholipid membrane integrity under osmotic and oxidative stress were explored using giant unilamellar vesicles as model cell membranes. Our results suggest that the adsorption of the polymers on the membrane surface is responsible for the cell membrane resealing process due to its capability of slowing down the surface hydration dynamics.

Effect of Secondary Doping Using Sorbitol on Structure and Transport Properties of PEDOT-PSS Thin Films

Science.gov (United States)

Khasim, Syed; Pasha, Apsar; Roy, Aashish S.; Parveen, Ameena; Badi, Nacer

2017-07-01

Poly(3,4-ethylene dioxythiophene):poly(styrenesulphonate) (PEDOT-PSS) in the recent past has emerged as one of the most fascinating conducting polymers for many device applications. The unique feature of PEDOT-PSS is its transparency in the entire visible spectrum with excellent thermal stability. The PEDOT-PSS as prepared as an aqueous dispersion has very low conductivity, and it hinders the performance of a device. In this work we report the conductivity enhancement of PEDOT-PSS thin films through secondary doping using a polar organic solvent such as sorbitol. The mechanism of conductivity enhancement was studied through various physical and chemical characterizations. The effect of sorbitol concentration on structure and transport properties of PEDOT-PSS thin films was investigated in detail. The structural and morphological modifications in PEDOT-PSS due to the addition of sorbitol was studied through Fourier transform spectroscopy, Ultra Violet-visible spectroscopy, theromogravimetric analysis, scanning electron microscopy and atomic force microscopy. The interactions resulting from conformational changes of PEDOT chains that changes from coiled to linear structure due to the sorbitol treatment significantly improves the conductivity of PEDOT-PSS films. The secondary doping of sorbitol reduces the energy barrier that facilitates the charge carrier hopping leading to enhanced conductivity. We have observed that the conductivity of PEDOT-PSS thin films was increased by two fold due to sorbitol treatment when compared to conductivity of pure PEDOT-PSS. We have carried out detailed analysis of dielectric parameters of sorbitol-treated PEDOT-PSS films and found that sorbitol treatment has a significant effect on various dielectric attributes of PEDOT-PSS films. Hence, secondary doping using sorbitol could be a useful way to effectively tailor the conductivity and dielectric properties of PEDOT-PSS thin films that can be used as flexible electrodes in

Water co-adsorption and electric field effects on borohydride structures on Os(1 1 1) by first-principles calculations

Energy Technology Data Exchange (ETDEWEB)

Escaño, Mary Clare Sison, E-mail: mcescano@u-fukui.ac.jp [Graduate School of Engineering, University of Fukui, 3-9-1 Bunkyo, Fukui 910-8507 (Japan); Arevalo, Ryan Lacdao [Department of Precision Science and Technology and Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Gyenge, Elod [Department of Chemical and Biological Engineering, The University of British Columbia, Vancouver, BC, Canada V6T 1Z3 (Canada); Kasai, Hideaki [Department of Precision Science and Technology and Applied Physics, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

2013-12-15

Highlights: ► Difference in Pt, Os electronic structures lead to different borohydride structures. ► Promotion of B–H bond breaking on Os due to water effects. ► Control of borohydride structure on Os catalyst using electric field. -- Abstract: Periodic density functional theory calculations are performed to investigate the nature of the BH{sub 4ad} and its interaction with H{sub 2}O{sub ad} in the presence of homogenous electric field. We observed a significant charge polarity of BH{sub 4ad} on Os(1 1 1) and such property could explain the electrostatic interaction with water monomer (H{sub ad}) with its HOH plane parallel to the surface. This interaction changes the BH{sub ad} molecular structure to BH{sub 3ad} + H{sub ad}. In the presence of homogenous electric field, the water co-adsorption effect is reduced due to the stabilization of H{sub 2}O{sub ad} on the surface and the deviation of the O–H bond from the plane, decreasing the electrostatic interaction between BH{sub 4ad} and H{sub 2}O{sub ad}. These fundamental findings imply accessible control of borohydride structures on an electrode surface, which could be relevant for direct borohydride fuel cell (DBFC) and reversible hydrogen storage/release applications.

Water co-adsorption and electric field effects on borohydride structures on Os(1 1 1) by first-principles calculations

International Nuclear Information System (INIS)

Escaño, Mary Clare Sison; Arevalo, Ryan Lacdao; Gyenge, Elod; Kasai, Hideaki

2013-01-01

Highlights: ► Difference in Pt, Os electronic structures lead to different borohydride structures. ► Promotion of B–H bond breaking on Os due to water effects. ► Control of borohydride structure on Os catalyst using electric field. -- Abstract: Periodic density functional theory calculations are performed to investigate the nature of the BH 4ad and its interaction with H 2 O ad in the presence of homogenous electric field. We observed a significant charge polarity of BH 4ad on Os(1 1 1) and such property could explain the electrostatic interaction with water monomer (H ad ) with its HOH plane parallel to the surface. This interaction changes the BH ad molecular structure to BH 3ad + H ad . In the presence of homogenous electric field, the water co-adsorption effect is reduced due to the stabilization of H 2 O ad on the surface and the deviation of the O–H bond from the plane, decreasing the electrostatic interaction between BH 4ad and H 2 O ad . These fundamental findings imply accessible control of borohydride structures on an electrode surface, which could be relevant for direct borohydride fuel cell (DBFC) and reversible hydrogen storage/release applications

Soil-structure interaction effects for laterally excited liquid-tank system

International Nuclear Information System (INIS)

Tang, Yu; Veletsos, A.S.

1992-01-01

Following a brief review of the mechanical model for liquid-storage tanks which permits consideration of the effects of tank and ground flexibility, and lateral and rocking base excitations, the effects of both kinematic and inertia interaction effects on the response of the tank-liquid system are examined and elucidated. The free-field motion is defined by a power spectral density function and an incoherence function, which characterizes the spatial variability of the ground motion due to the vertically incident incoherence waves. The quantities examined are the ensemble means of the peak values of the response. The results are compared with those obtained for no soil-structure interaction and for kinematic interaction to elucidate the nature and relative importance of the two interactions. Only the impulsive actions are examined, the convective actions are for all practical purposes unaffected by both kinematic and inertia interactions. It is shown that the major reduction of the response is attributed to inertia interaction. 20 refs

Effect of Al-doped YCrO3 on structural, electronic and magnetic properties

Science.gov (United States)

Durán, A.; Verdín, E.; Conde, A.; Escamilla, R.

2018-05-01

Structural, dielectric and magnetic properties were investigated in the YCr1-xAlxO3 with 0 cell volume of the orthorhombic structure without changes in the oxidation state of the Cr3+ ions. We discuss two mechanisms that could have a significant influence on the magnetic properties. The first is related to local deformation occurring for x structure. The local deformation is controlled by the inclination of the octahedrons and the octahedral distortion having a strong effect on the TN and the coercive field at low Al concentrations. On the other hand, the decreasing of the magnetization values (Mr and Hc) is ascribed to changes in the electronic structure, which is confirmed by a decreasing of the contribution of Cr 3d states at Fermi level due to increasing Al3+ content. Thus, we analyzed and discussed that both mechanisms influence the electronic properties of the YCr1-xAlxO3 solid solution.

Effect on non-linear soil-structure interaction due to base slab uplift on the seismic response of a high-temperature gas-cooled reactor (HTGR)

International Nuclear Information System (INIS)

Kennedy, R.P.; Short, S.A.

1976-01-01

In high seismic regions it has often been the practice to use oversized base slabs for the major nuclear power plant structures in order to prevent, or at least minimize the amount of dynamic base slab uplift which will result from the overturning moments developed during seismic ground motion. Two major reasons have been expressed as to why dynamic base slab uplift should be minimized: (1) As nuclear power plants are normally designed for seismic loadings based upon linear analysis, and since soil-structure interaction becomes nonlinear when only a portion of the base slab is in contact with the soil, linear elasticity analysis may be acceptable if base slab uplift occurs (as the resultant design loads may be incorrect), and (2) substantial uplift could cause excessive toe pressures in the supporting soil and significant impact forces when the slab recontacts the soil. The primary purpose of this paper is to evaluate the importance of the nonlinear soil-structure interaction effects resulting from substantial base slab uplift occurring during a seismic excitation. The structure for this investigation consisted of the containment building and prestressed reactor vessel (PCRV) for a typical HTGR plant. A simplified dynamic mathematical model was utilized consisting of a conventional lumped mass structure with soil-structure interaction accounted for by translational and rotational springs whose properties are determined by elastic half space theory. Three different site soil conditions (a rock site, a moderately stiff soil, and a soft soil) and two levels of horizontal ground motion (0.3 and 0.5 g earthquakes) were considered. (Auth.)

Effects of non-structural components and soil-structure interaction on the seismic response of framed structures

Science.gov (United States)

Ditommaso, Rocco; Auletta, Gianluca; Iacovino, Chiara; Nigro, Antonella; Carlo Ponzo, Felice

2017-04-01

In this paper, several nonlinear numerical models of reinforced concrete framed structures have been defined in order to evaluate the effects of non-structural elements and soil-structure interaction on the elastic dynamic behaviour of buildings. In the last few years, many and various studies have highlighted the significant effects derived from the interaction between structural and non-structural components on the main dynamic characteristics of a building. Usually, structural and non-structural elements act together, adding both masses and stiffness. The presence of infill panels is generally neglected in the design process of structural elements, although these elements can significantly increase the lateral stiffness of a structure leading to a modification in the dynamic properties. Particularly, at the Damage Limit State (where an elastic behaviour is expected), soil-structure interaction effects and non-structural elements may further affect the elastic natural period of buildings, changing the spectral accelerations compared with those provided by seismic codes in case of static analyses. In this work, a parametric study has been performed in order to evaluate the elastic fundamental period of vibration of buildings as a function of structural morphology (height, plan area, ratio between plan dimensions), infills presence and distribution and soil characteristics. Acknowledgements This study was partially funded by the Italian Department of Civil Protection within the project DPC-RELUIS 2016 - RS4 ''Seismic observatory of structures and health monitoring'' and by the "Centre of Integrated Geomorphology for the Mediterranean Area - CGIAM" within the Framework Agreement with the University of Basilicata "Study, Research and Experimentation in the Field of Analysis and Monitoring of Seismic Vulnerability of Strategic and Relevant Buildings for the purposes of Civil Protection and Development of Innovative Strategies of Seismic Reinforcement".

Load kick-back effects due to activation of demand response in view of distribution grid operation

DEFF Research Database (Denmark)

Han, Xue; Sossan, Fabrizio; Bindner, Henrik W.

2014-01-01

. The paper has shown how aggregated consumption dynamics introduce new peaks in the system due to the synchronous behaviors of a portfolio of homogeneous DSRs, which is instructed by the flexibility management system. This dynamic effect is recognized as load kick-back effect. The impact of load kick......-back effects onto the distribution grid is analysed in this paper by establishing scenarios based on the estimation of DSR penetration levels from the system operator. The results indicate some risks that the activation of demand response may create critical peaks in the local grid due to kick-back effects....

Effect of gamma irradiation on the structural, mechanical and optical properties of polytetrafluoroethylene sheet

Science.gov (United States)

Mohammadian-Kohol, M.; Asgari, M.; Shakur, H. R.

2018-04-01

In this study, the effects of gamma radiation on the chemical structure, mechanical and optical properties of polytetrafluoroethylene (PTFE) sheet were investigated with various doses up to 12 kGy. The chemical changes in the structure were studied by FTIR spectroscopy. Also, effects of radiation on the different mechanical parameters such as Young's modulus, toughness, strain, and stress were studied at the maximum tolerable force and the fracture points. Furthermore, changing the various optical parameters such as absorption coefficient, Urbach energy, optical band gaps, refractive index, optical dispersion parameters and plasma resonance frequency were studied by UV-visible spectroscopy. Formation of a band at 1594 cm-1, which was belonged to double carbon bonds, indicated that chain-scission was occurred at 12 kGy gamma irradiation dose. As well, the mechanical results showed an increase in the elastic behavior of PTFE sheets and a decrease in the plastic behavior of it with absorbed dose increasing. Moreover, the results showed that gamma irradiation can effectively change the various optical properties of PTFE sheets due to different phenomena such as degradation of the main chains, occurring chain-scission, formation of free radicals and cross-linking in the polymer structure.

Realistic Features in Analysing the Effect of the Seismic Motion upon Localized Structures Considering Base Isolation Influence on Their Dynamic Behaviour

Science.gov (United States)

Apostol, Bogdan Felix; Florin Balan, Stefan; Ionescu, Constantin

2017-12-01

The effects of the earthquakes on buildings and the concept of seismic base isolation are investigated by using the model of the vibrating bar embedded at one end. The normal modes and the eigenfrequencies of the bar are highlighted and the amplification of the response due to the excitation of the normal modes (eigenmodes) is computed. The effect is much enhanced at resonance, for oscillating shocks which contain eigenfrequencies of the bar. Also, the response of two linearly joined bars with one end embedded is calculated. It is shown that for very different elastic properties the eigenfrequencies are due mainly to the “softer” bar. The effect of the base isolation in seismic structural engineering is assessed by formulating the model of coupled harmonic oscillators, as a simplified model for the structure building-foundation viewed as two coupled vibrating bars. The coupling decreases the lower eigenfrequencies of the structure and increases the higher ones. Similar amplification factors are derived for coupled oscillators at resonance with an oscillating shock.

Radiation Effects on Spacecraft Structural Materials

International Nuclear Information System (INIS)

Wang, Jy-An J.; Ellis, Ronald J.; Hunter, Hamilton T.; Singleterry, Robert C. Jr.

2002-01-01

Research is being conducted to develop an integrated technology for the prediction of aging behavior for space structural materials during service. This research will utilize state-of-the-art radiation experimental apparatus and analysis, updated codes and databases, and integrated mechanical and radiation testing techniques to investigate the suitability of numerous current and potential spacecraft structural materials. Also included are the effects on structural materials in surface modules and planetary landing craft, with or without fission power supplies. Spacecraft structural materials would also be in hostile radiation environments on the surface of the moon and planets without appreciable atmospheres and moons around planets with large intense magnetic and radiation fields (such as the Jovian moons). The effects of extreme temperature cycles in such locations compounds the effects of radiation on structural materials. This paper describes the integrated methodology in detail and shows that it will provide a significant technological advance for designing advanced spacecraft. This methodology will also allow for the development of advanced spacecraft materials through the understanding of the underlying mechanisms of material degradation in the space radiation environment. Thus, this technology holds a promise for revolutionary advances in material damage prediction and protection of space structural components as, for example, in the development of guidelines for managing surveillance programs regarding the integrity of spacecraft components, and the safety of the aging spacecraft. (authors)

Effect of temperature, of oxygen content and the downstream effect on corrosion rate of structural materials in liquid sodium

International Nuclear Information System (INIS)

Ilincev, G.

1988-01-01

The effects were experimentally tested of temperature and of oxygen content on the corrosion rate of structural materials in liquid sodium and on reducing the corrosion rate down the sodium stream. The results of the experiments are shown in graphs and tables and are discussed in detail. The duration of all tests was standard 1,000 hours. The test parameters were set such as to determine the effect of temperature on corrosion of a quantity of various materials in sodium with a low oxygen content (1.2 to 2 ppm) at temperatures of 500 to 800 degC and in sodium with a high oxygen content (345 ppm) at temperatures of 500 to 700 degC. More experiments served the determination of the effect of a different oxygen content varying between 1.2 and 2 ppm at a constant temperature of 600 degC. The materials being tested included main structural materials used for fast reactor construction and materials allowing to establish the effect of main alloying elements on their corrosion in liquid sodium of different temperatures and purity grades. The relationships showing the effects of temperature and oxygen content in sodium on the rate of corrosion of various structural materials in hot parts of the installation and on the reduction in the rate of corrosion downstream due to sodium saturation with corrosion products were constructed using the experimental results. (Z.M.). 15 figs., 2 tabs., 7 refs

Magnetic field effect on Gd2(MoO4)3 domain structure formation in the phase transformation range

International Nuclear Information System (INIS)

Flerova, S.A.; Tsinman, I.L.

1987-01-01

The behaviour of ferroelastic-ferroelectric domain structure of gadolinium molybdate crystal (GMO)during its formation in the magnetic field in the vicinity of phase transformation is studied.It is shown that the formation of domain structure in the presence of a temperature gradient occurs in the field of mechanical stresses whose mainly stretching effect is concentrated near phase boundaries.The magnetic field intensifies summary mechanical stresses where a domain structure in a ferroelectric phase is formed due to interaction with the elements of inhomogeneous and differently oriented currents near phase boundaries

Rethinking the role of edaphic condition in halophyte vegetation degradation on salt marshes due to coastal defense structure

Science.gov (United States)

Xie, Tian; Cui, Baoshan; Bai, Junhong; Li, Shanze; Zhang, Shuyan

2018-02-01

Determining how human disturbance affects plant community persistence and species conservation is one of the most pressing ecological challenges. The large-scale disturbance form defense structures usually have a long-term and potential effect on phytocommunity in coastal saltmarshes. Coastal defense structures usually remove the effect of tidal wave on tidal salt marshes. As a consequence, edaphic factors such as the salinity and moisture contents are disturbed by tidal action blocking. However, few previous studies have explicitly addressed the response of halophyte species persistence and dynamics to the changing edaphic conditions. The understanding of the response of species composition in seed banks and aboveground vegetation to the stress is important to identify ecological effect of coastal defense structures and provide usefully insight into restoration. Here, we conducted a field study to distinguish the density, species composition and relationships of seed bank with aboveground vegetation between tidal flat wetlands with and without coastal defense structures. We also addressed the role of edaphic condition in vegetation degradation caused by coastal defense structures in combination with field monitor and greenhouse experiments. Our results showed the density of the seed bank and aboveground vegetation in the tidal flat without coastal defense structures was significantly lower than the surrounded flat with coastal defense structures. A total of 14 species were founded in the surrounded flat seed bank and 11 species in the tidal flat, but three species were only recorded in aboveground vegetation of the tidal flat which was much lower than 24 aboveground species in the surrounded flat. The absent of species in aboveground vegetation contributed to low germination rate which depend on the edaphic condition. The germination of seeds in the seed bank were inhabited by high soil salinity in the tidal flat and low soil moisture in the surrounded flat. Our

Fine structure of the isoscalar giant quadrupole resonance in 40Ca due to Landau damping?

International Nuclear Information System (INIS)

Usman, I.; Buthelezi, Z.; Carter, J.; Cooper, G.R.J.; Fearick, R.W.; Foertsch, S.V.; Fujita, H.; Fujita, Y.; Kalmykov, Y.; Neumann-Cosel, P. von; Neveling, R.; Papakonstantinou, P.; Richter, A.; Roth, R.; Shevchenko, A.; Sideras-Haddad, E.; Smit, F.D.

2011-01-01

The fragmentation of the Isoscalar Giant Quadrupole Resonance (ISGQR) in 40 Ca has been investigated in high energy-resolution experiments using proton inelastic scattering at E p =200 MeV. Fine structure is observed in the region of the ISGQR and its characteristic energy scales are extracted from the experimental data by means of a wavelet analysis. The experimental scales are well described by Random Phase Approximation (RPA) and second-RPA calculations with an effective interaction derived from a realistic nucleon-nucleon interaction by the Unitary Correlation Operator Method (UCOM). In these results characteristic scales are already present at the mean-field level pointing to their origination in Landau damping, in contrast to the findings in heavier nuclei and also to SRPA calculations for 40 Ca based on phenomenological effective interactions, where fine structure is explained by the coupling to two-particle-two-hole (2p-2h) states.

Assessment of the Vibrations Effects Caused by Technical Seismicity Due to the Railway traffic on High-sensitivity Machinery

Science.gov (United States)

Papán, Daniel; Valašková, Veronika; Demeterová, Katarína

2016-10-01

The numerical and experimental approach in structural dynamics problems is more and more current nowadays. This approach is applied and solved in many research and developing institutions of the all the world. Vibrations effect caused by passing trains used in manufacturing facilities can affect the quality of the production activity. This effect is possible to be solved by a numerical or an experimental way. Numerical solution is not so financially and time demanding. The main aim of this article is to focus on just experimental measurement of this problem. In this paper, the case study with measurement due to cramped conditions realized in situ is presented. The case study is located close to railway. The vibration effect caused by passing trains on the high-sensitivity machinery contained in this object were observed. The structure was a high-sensitivity machine that was placed in a construction process. For the measurements, the high-sensitivity standard vibrations equipment was used. The assessments of measurements’ results were performed for the technological conditions and Slovak Standard Criteria. Both of these assessments were divided to amplitude and frequency domain. The amplitude criterion is also divided to peak particle velocity and RMS (Root Mean Square). Frequency domain assessment were realised using the frequency response curves obtained from high-sensitivity machinery manufacturer. The frequency limits are established for each axis of triaxle system. The measurement results can be predicted if the vibration have to be reduced. Measurement implemented in the production hall should obtain materials to determine the seismic loading and response of production machinery caused by technical seismicity.

Structural transformations in Mn2NiGa due to residual stress

International Nuclear Information System (INIS)

Singh, Sanjay; Maniraj, M.; D'Souza, S. W.; Barman, S. R.; Ranjan, R.

2010-01-01

Powder x-ray diffraction study of Mn 2 NiGa ferromagnetic shape memory alloy shows the existence of a 7M monoclinic modulated structure at room temperature (RT). The structure of Mn 2 NiGa is found to be highly dependent on residual stress. For higher stress, the structure is tetragonal at RT, and for intermediate stress it is 7M monoclinic. However, only when the stress is considerably relaxed, the structure is cubic, as is expected at RT since the martensitic transition temperature is 230 K.

Effect of crumb cellular structure characterized by image analysis on cake softness.

Science.gov (United States)

Dewaest, Marine; Villemejane, Cindy; Berland, Sophie; Neron, Stéphane; Clement, Jérôme; Verel, Aliette; Michon, Camille

2017-10-04

Sponge cake is a cereal product characterized by an aerated crumb and appreciated for its softness. When formulating such product, it is interesting to be able to characterize the crumb structure using image analysis and to bring knowledge about the effects of the crumb cellular structure on its mechanical properties which contribute to softness. An image analysis method based on mathematical morphology was adapted from the one developed for bread crumb. In order to evaluate its ability to discriminate cellular structures, series of cakes were prepared using two rather similar emulsifiers but also using flours with different aging times before use. The mechanical properties of the crumbs of these different cakes were also characterized. It allowed a cell structure classification taking into account cell size and homogeneity, but also cell wall thickness and the number of holes in the walls. Interestingly, the cellular structure differences had a larger impact on the aerated crumb Young modulus than the wall firmness. Increasing the aging time of flour before use leads to the production of firmer crumbs due to coarser and inhomogeneous cellular structures. Changing the composition of the emulsifier may change the cellular structure and, depending on the type of the structural changes, have an impact on the firmness of the crumb. Cellular structure rather than cell wall firmness was found to impact cake crumb firmness. The new fast and automated tool for cake crumb structure analysis allows detecting quickly any change in cell size or homogeneity but also cell wall thickness and number of holes in the walls (openness degree). To obtain a softer crumb, it seems that options are to decrease the cell size and the cell wall thickness and/or to increase the openness degree. It is then possible to easily evaluate the effects of ingredients (flour composition, emulsifier …) or change in the process on the crumb structure and thus its softness. Moreover, this image

SUPPRESSION OF DIELECTRONIC RECOMBINATION DUE TO FINITE DENSITY EFFECTS

International Nuclear Information System (INIS)

Nikolić, D.; Gorczyca, T. W.; Korista, K. T.; Ferland, G. J.; Badnell, N. R.

2013-01-01

We have developed a general model for determining density-dependent effective dielectronic recombination (DR) rate coefficients in order to explore finite-density effects on the ionization balance of plasmas. Our model consists of multiplying by a suppression factor those highly-accurate total zero-density DR rate coefficients which have been produced from state-of-the-art theoretical calculations and which have been benchmarked by experiment. The suppression factor is based upon earlier detailed collision-radiative calculations which were made for a wide range of ions at various densities and temperatures, but used a simplified treatment of DR. A general suppression formula is then developed as a function of isoelectronic sequence, charge, density, and temperature. These density-dependent effective DR rate coefficients are then used in the plasma simulation code Cloudy to compute ionization balance curves for both collisionally ionized and photoionized plasmas at very low (n e = 1 cm –3 ) and finite (n e = 10 10 cm –3 ) densities. We find that the denser case is significantly more ionized due to suppression of DR, warranting further studies of density effects on DR by detailed collisional-radiative calculations which utilize state-of-the-art partial DR rate coefficients. This is expected to impact the predictions of the ionization balance in denser cosmic gases such as those found in nova and supernova shells, accretion disks, and the broad emission line regions in active galactic nuclei.

DYNAMICS OF STRUCTURAL AND FUNCTIONAL STATUS OF MYOCARDIUM DUE TO COMBINATION THERAPY WITH AMLODIPINE AND BISOPROLOL IN PATIENTS WITH ARTERIAL HYPERTENSION

Directory of Open Access Journals (Sweden)

I. L. Zapesochnaya

2015-09-01

Full Text Available Aim. To evaluate the effect of 6-month therapy with combination of amlodipine and bisoprolol on the structural and functional status of the myocardium in hypertensive patients who work in the Far North.Material and methods. 140 hypertensive patients who live in the Khanty-Mansiysk Autonomous District - Yugra were divided into two groups depending on arrangement of working time. The first group included 72 patients who work only day shift; the second group – 68 patients who work alternate (day/night shifts. Combination therapy with amlodipine and bisoprolol assigned to all patients. Echocardiography was performed at baseline, after 12 weeks, and after 6 months of therapy.Results. The target blood pressure (BP level in group 1 was achieved in 92.9%. A share of patients with normal left ventricular (LV geometry increased from 37.5 to 44.8%; a share of patients with concentric and eccentric LV hypertrophy (LVH decreased from 30.6 to 23.9% and 19.4 to 19.2%, respectively. Target BP level in group 2 was achieved in 87.9%. A share of patients with normal LV geometry increased from 23.5 to 33.3%; while share of patients with concentric and eccentric LVH decreased from 45.6 to 38.1% and from 19.1 to 17.4%, respectively. A positive correlation between LV myocardial index and average daily systolic and diastolic BP was found.Conclusion. Revealed changes in BP and in LV structure and function due to treatment with amlodipine and bisoprolol can be considered as cardioprotective effect of this combination in hypertensive patients who work in the Far North. This effect was more pronounced in hypertensive patients working alternate (day/night shifts.

DYNAMICS OF STRUCTURAL AND FUNCTIONAL STATUS OF MYOCARDIUM DUE TO COMBINATION THERAPY WITH AMLODIPINE AND BISOPROLOL IN PATIENTS WITH ARTERIAL HYPERTENSION

Directory of Open Access Journals (Sweden)

I. L. Zapesochnaya

2014-01-01

Full Text Available Aim. To evaluate the effect of 6-month therapy with combination of amlodipine and bisoprolol on the structural and functional status of the myocardium in hypertensive patients who work in the Far North.Material and methods. 140 hypertensive patients who live in the Khanty-Mansiysk Autonomous District - Yugra were divided into two groups depending on arrangement of working time. The first group included 72 patients who work only day shift; the second group – 68 patients who work alternate (day/night shifts. Combination therapy with amlodipine and bisoprolol assigned to all patients. Echocardiography was performed at baseline, after 12 weeks, and after 6 months of therapy.Results. The target blood pressure (BP level in group 1 was achieved in 92.9%. A share of patients with normal left ventricular (LV geometry increased from 37.5 to 44.8%; a share of patients with concentric and eccentric LV hypertrophy (LVH decreased from 30.6 to 23.9% and 19.4 to 19.2%, respectively. Target BP level in group 2 was achieved in 87.9%. A share of patients with normal LV geometry increased from 23.5 to 33.3%; while share of patients with concentric and eccentric LVH decreased from 45.6 to 38.1% and from 19.1 to 17.4%, respectively. A positive correlation between LV myocardial index and average daily systolic and diastolic BP was found.Conclusion. Revealed changes in BP and in LV structure and function due to treatment with amlodipine and bisoprolol can be considered as cardioprotective effect of this combination in hypertensive patients who work in the Far North. This effect was more pronounced in hypertensive patients working alternate (day/night shifts.

Potential collapse due to geological structures influence in Seropan Cave, Gunung Kidul, Yogyakarta, Indonesia

Science.gov (United States)

Nugroho, B.; Pranantya, P. A.; Witjahjati, R.; Rofinus

2018-01-01

This study aims to estimate the potential collapse in the Seropan cave, based on the existing geological structure conditions in the cave. This is very necessary because in the Seropan cave will be built Microhydro installation for power plants. The electricity will be used to raise the underground river water in the cave to a barren soil surface, which can be used for surface irrigation. The method used is analysis the quality of rock mass along the cave. Analysis of rock mass quality using Geomechanical Classification or Rock Mass Rating (RMR), to determine the magnitude of the effect of geological structure on rock mass stability. The research path is divided into several sections and quality analysis is performed on each section. The results show that the influence of geological structure is very large and along the cave where the research there are several places that have the potential to collapse, so need to get serious attention in handling it. Nevertheless, the construction of this Microhydro installation can still be carried out by making a reinforcement on potentially collapsing parts

Magnetic field effects on the crust structure of neutron stars

Science.gov (United States)

Franzon, B.; Negreiros, R.; Schramm, S.

2017-12-01

We study the effects of high magnetic fields on the structure and on the geometry of the crust in neutron stars. We find that the crust geometry is substantially modified by the magnetic field inside the star. We build stationary and axis-symmetric magnetized stellar models by using well-known equations of state to describe the neutron star crust, namely, the Skyrme model for the inner crust and the Baym-Pethick-Sutherland equation of state for the outer crust. We show that the magnetic field has a dual role, contributing to the crust deformation via the electromagnetic interaction (manifested in this case as the Lorentz force) and by contributing to curvature due to the energy stored in it. We also study a direct consequence of the crust deformation due to the magnetic field: the thermal relaxation time. This quantity, which is of great importance to the thermal evolution of neutron stars, is sensitive to the crust properties, and, as such, we show that it may be strongly affected by the magnetic field.

Passive microwave remote sensing of soil moisture - The effect of tilled row structure

Science.gov (United States)

Wang, J. R.; Newton, R. W.; Rouse, J. W., Jr.

1980-01-01

The tilled row structure in agricultural fields is one of the important factors affecting observations of microwave emission from such fields. Measurements of this effect were performed with L-band and X-band radiometers mounted on a mobile truck on a bare 40 m x 45 m row tilled field; the soil moisture content during measurements ranged from 10 to 30% by dry weight. Results showed that the variations of the antenna temperatures with incident angle changed with the azimuth angle measured from the row direction. It is found that the observed difference between horizontally and vertically polarized antenna temperatures is due to the change in the local angle of field emission within the antenna field of view caused by the large-scale row structure.

Fatigue of LMFBR piping due to flow stratification

International Nuclear Information System (INIS)

Woodward, W.S.

1983-01-01

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

Fatigue of LMFBR piping due to flow stratification

Energy Technology Data Exchange (ETDEWEB)

Woodward, W.S.

1983-01-01

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

Electronic excitation induced structural and optical modifications in InGaN/GaN quantum well structures grown by MOCVD

Energy Technology Data Exchange (ETDEWEB)

Prabakaran, K.; Ramesh, R.; Jayasakthi, M.; Surender, S.; Pradeep, S. [Crystal Growth Centre, Anna University, Chennai (India); Balaji, M. [National Centre for Nanoscience and Nanotechnology, University of Madras, Guindy Campus, Chennai (India); Asokan, K. [Inter-University Accelerator Centre, New Delhi (India); Baskar, K., E-mail: drbaskar2009@gmail.com [Crystal Growth Centre, Anna University, Chennai (India); Manonmaniam Sundaranar University, Tirunelveli (India)

2017-03-01

Highlights: • Effects on InGaN/GaN QW structures by Au{sup 7+} (100 MeV) ion have been investigated. • Structural defects of the irradiated InGaN/GaN QW structures are determined. • The intermixing effect in irradiated InGaN/GaN QW structures were understood. • Modified luminescence was observed in the PL spectra due to heavy ion irradiation. • Surface modification was observed due to the heavy ion irradiation. - Abstract: The present study focuses on the electronic excitation induced structural and optical properties of InGaN/GaN quantum well (QW) structures grown by metal organic chemical vapor deposition technique. These excitations were produced using Au{sup 7+} ion irradiation with 100 MeV energy. The X-ray rocking curves intensity and full width at half-maximum values corresponding to the planes of (0 0 0 2) and (1 0 −1 5) of the irradiated QW structures show the modifications in the screw and edge-type dislocation densities vary with the ion fluences. The structural characteristics using the reciprocal space mapping indicate the intermixing effects in InGaN/GaN QW structures. Atomic force microscopy images confirmed the presence of nanostructures and the surface modification due to heavy ion irradiation. The irradiated QW structures exhibited degraded photoluminescence intensity and a subsequent decrease in the yellow luminescence band intensity with the fluences of 1 × 10{sup 11} and 5 × 10{sup 12} ions/cm{sup 2} compared to the pristine QW structures.

Effects of Novel Structure Bonding Materials on Properties of Aeronautical Acrylic

Directory of Open Access Journals (Sweden)

LI Zhisheng

2017-06-01

Full Text Available Novel structure bonding materials, J-351 epoxy adhesive film with low curing temperature and liquid modified acrylate SY-50s adhesive were chosen and characterized. The effects of adhesives on the mechanical properties of acrylic were studied. The results reveal that both adhesives have excellent bonding properties to acrylic. The stress-solvent crazing value of J-351 is higher than that of SY-50s. With the application of adhesive on the surface, mechanical properties of acrylic are declined. Casting acrylic shows more drastic decline than that of oriented acrylic. Through the characterization of fracture surface, we find that fracture of tensile sample derives from the side with adhesive. Mechanical properties of acrylic are more sensitive to SY-50s, because the liquid adhesive presents integrate bonding interface with acrylic. The interface between J-351 and acrylic is clear, making acrylic insensitive to J-351 film. Edge attachment strength of samples bonded with J-351 are higher than that of samples bonded with SY-50s due to the effects of adhesives on acrylic. J-351 epoxy adhesive film presents preferable application performance in the structure bonding of aeronautical acrylic.

Thyroid cancer due to biological effects of ionizing radiation

International Nuclear Information System (INIS)

Galvão, T.; Castro, N.; Teixeira, D.; Matuo, R.

2017-01-01

Thyroid cancer is considered the most common in the region of the head and neck. It can be caused by spontaneous mutations, but also by ionizing radiation. The effect of ionizing radiation on the thyroid has been studied for several decades. The exact cause of the cancer is not known, but people with certain risk factors are more vulnerable, such as exposure to radiation, family history and age over 40 years. The thyroid is susceptible to the effects of radiation and is involved in the field of diagnostic or therapeutic irradiation, and may present functional and structural changes. Radiation can act in different ways, such as inhibiting or activating specific functions of the follicular epithelium, reducing the number of functioning follicles, altering vascularization or vascular permeability and inducing immune reactions. These morphological and histological changes may be related to the development of thyroid cancer

Analytical model of cracking due to rebar corrosion expansion in concrete considering the structure internal force

Science.gov (United States)

Lin, Xiangyue; Peng, Minli; Lei, Fengming; Tan, Jiangxian; Shi, Huacheng

2017-12-01

Based on the assumptions of uniform corrosion and linear elastic expansion, an analytical model of cracking due to rebar corrosion expansion in concrete was established, which is able to consider the structure internal force. And then, by means of the complex variable function theory and series expansion technology established by Muskhelishvili, the corresponding stress component functions of concrete around the reinforcement were obtained. Also, a comparative analysis was conducted between the numerical simulation model and present model in this paper. The results show that the calculation results of both methods were consistent with each other, and the numerical deviation was less than 10%, proving that the analytical model established in this paper is reliable.

Cracking in reinforced concrete structures due to imposed deformations

Energy Technology Data Exchange (ETDEWEB)

Nagy, A.

1997-04-01

This thesis is concerned with modeling of the cracking process in reinforced concrete due to imposed deformations. Cracking is investigated both at early ages, during hydration, and at mature age when the final properties of the concrete are reached. One of the most important material characteristics of the concrete at early ages, the Young`s modulus is determined by means of a dynamic method called the resonance frequency method. 40 refs

Engineering characterization of ground motion. Task II: Soil structure interaction effects on structural response

Energy Technology Data Exchange (ETDEWEB)

Luco, J E; Wong, H L [Structural and Earthquake Engineering Consultants, Inc., Sierra Madre, CA (United States); Chang, C -Y; Power, M S; Idriss, I M [Woodward-Clyde Consultants, Walnut Creek, CA (United States)

1986-08-01

This report presents the results of part of a two-task study on the engineering characterization of earthquake ground motion for nuclear power plant design. The overall objective of this research program sponsored by the U.S. Nuclear Regulatory Commission (USNRC) is to develop recommendations for methods for selecting design response spectra or acceleration time histories to be used to characterize motion at the foundation level of nuclear power plants. Task I of the study, which is presented in Vol. 1 of NUREG/CR-3805, developed a basis for selecting design response spectra taking into account the characteristics of free-field ground motion found to be significant in causing structural damage. Task II incorporates additional considerations of effects of spatial variations of ground motions and soil-structure interaction on foundation motions and structural response. The results of Task II are presented in Vols. 2 through of NUREG/CR-3805 as follows: Vol. 2 effects of ground motion characteristics on structural response considering localized structural nonlinearities and soil-structure interaction effects; Vol. 3 observational data on spatial variations of earthquake ground motions; Vol. 4 soil-structure interaction effects on structural response; and Vol. 5, summary based on Tasks I and II studies. This report presents the results of the Vol. 4 studies.

Evaluation of Detrimental Effects on Mechanical Properties of Zry-4 Due to Hydrogen Absorption by means of Scanning Electron Microscopy (SEM) In-Situ Observation of Crack Propagation

International Nuclear Information System (INIS)

Fernandez, L; Fernandez, G.E; Bertolino, G; Meyer, G

2001-01-01

The study of mechanical properties degradation of zirconium alloys due to hydrides assumes fundamental importance in the nuclear industry.During normal nuclear reactors operation, structural parts absorbed hydrogen generated from radiolysis of water, causing detrimental effects on mechanical properties.As a consequence, these materials are easily cracked in the presence of mechanical solicitation due to loss of ductility of the hydride-phase.The presence of cracks indicates fracture mechanic as the most suitable methodology in the study of mechanical properties degradation.In this work we used the crack tip opening displacement (CTOD) criteria to evaluate the detrimental effects on mechanical properties with the observation in SEM of crack propagation.The samples used were SEN (B) of Zry-4 and cathodic homogenous charged with hydrogen concentrations lower than 400 ppm

DIFFERENTIAL EQUATION SIMULATION IN CALCULATION OF LATERAL AND TRANSVERSE-LONGITUDINAL BENDING OF FRAME STRUCTURES WITHOUT AND WITH DUE ACCOUNT OF VISCOELASTIC MATERIAL PROPERTIES

Directory of Open Access Journals (Sweden)

V. M. Ovsianko

2012-01-01

Full Text Available The paper reveals a brand-new direction in simulation of frame and continual structures while calculating static and dynamic loads and stability.  An electronic model has been synthesized  for an investigated object and then it has been analyzed not with the help of  specialized analog computing techniques but by means of high-performance software package for electronic circuit calculation using a personal computer.The given paper contains exact algebraic equations corresponding to differential equations for lateral bending calculation of frame structures without and with due account of viscoelastic material properties in compliance with the Kelvin model.The exact algebraic equation for a beam on elastic supports (or elastic Winkler foundation has been derived for quartic differential equation.The paper presents a number of exact algebraic equations which are equivalent to differential equations for transverse-longitudinal bending calculation of frame structures without and with due account of viscoelastic material properties when lateral and longitudinal loads are applied in the form of  impulses with any periods of their duration and any interchangeability. 

Early detection of micro-structural changes due to fatigue of non-corrosive austenitic stainless steels

International Nuclear Information System (INIS)

Kalkhof, D.; Niffenegger, M.; Grosse, M.

2003-03-01

In view of life extension efforts of nuclear power plants, many investigations are in progress in order to assess the structural integrity of different components. In many cases, this involves unexpected loads, which were not taken into account during design of components, e.g. temperature cycling arising from unforeseen stratification flow conditions. Under certain power plant transients (start-up/shut-down, hot stand-by, thermal stratification) at critical locations of piping and nozzles, material degradation caused by accumulated cyclic plastic strain takes place. However, materials subjected to cyclic loading exhibit changes in microstructure already before macroscopic crack initiation begins, this period covers a considerable part of fatigue life. Existing methods for in-service inspection are mainly specialised for crack detection. Advanced non-destructive testing methods for monitoring of material degradation are sensitive to any micro-structural changes in the material leading to a degradation of the mechanical properties. Therefore, these indirect methods require a careful interpretation of the measured signal in terms of micro-structural evolutions due to ageing. During cyclic loading of austenitic stainless steel, microstructural changes occur, which affect both the mechanical and the physical properties. Typical features are the rearrangement of dislocations and, in some cases, a deformation-induced martensitic phase transformation. In our investigation martensite formation was used as an indication for material degradation due to fatigue. Knowledge about mechanisms and influencing parameters of the martensitic transformation process is essential for the application in a lifetime monitoring system. The investigations showed that for a given austenitic stainless steel the deformation-induced martensite depends on the applied strain amplitude, the cycle number (usage factor, lifetime) and the temperature. It was demonstrated that the volume fraction of

Full-scale experimental and numerical study about structural behaviour of a thin-walled cold-formed steel building affected by ground settlements due to land subsidence

Directory of Open Access Journals (Sweden)

J. A. Ortiz

2015-11-01

Full Text Available Land subsidence due to ground water withdrawal is a problem in many places around the world (Poland, 1984. This causes differential ground settlements that affect masonry structures, because these structural materials do not exhibit an adequate performance beyond a certain level of angular distortion. This work presents the experimental and numerical results about a study regarding the performance of a full-scale thin-walled cold-formed steel building affected by ground differential settlements due to land subsidence. The experimental stage consisted in the construction of a test-building to be subjected to differential settlements in laboratory. The numerical stage consisted in performing a numerical non-linear static pull-down analysis simulating the differential ground settlements of the test-building. The results show that the structural performance of the tested building was very suitable in terms of ductility.

Numerical modeling of persian gulf salinity variations due to tidal effects

International Nuclear Information System (INIS)

Sabbagh Yazdi, S.R.

2004-01-01

Numerical modeling of salinity changes in marine environment of Persian Gulf is investigated in this paper. Computer simulation of the problem is performed by the solution of a convection-diffusion equation for salinity concentration coupled with the hydrodynamic equations. The hydrodynamic equations consist of shallow water equations of continuity and motion in horizontal plane. The effects of rain and evaporations are considered in the continuity equation and the effects of bed slope and friction, as well as Coriolis effects are considered in two equations of motion. The cell vertex finite volume method is applied for solving the governing equations on triangular unstructured meshes. Using unstructured meshes provides great flexibility for modeling the flow problems in arbitrary and complex geo metrics, such as Persia Gulf domain. The results of evaporation and Coriolis effects, as well as imposing river and tidal boundary conditions to the hydrodynamic model of Persian Gulf (considering variable topology rough bed) are compared with predictions of Admiralty Tide Table, Which are obtained from the harmonic analysis. The performance of the developed computer model is demonstrated by simulation of salinity changes due to inflow effects and diffusion effects as well as computed currents

A Study on the Embedment Effect in the Soil-Structure Interaction Analysis of the APR1400

International Nuclear Information System (INIS)

Young-Sun Jang; Kwang-Ho Joo; Chong-Hak Kim

2002-01-01

The SSI (Soil-Structure Interaction) analyses are being performed for the APR1400 (Advanced Power Reactor 1400 MWe, Old name - KNGR; Korean Next Generation Reactor) design, because the APR1400 is developed as a Standard Nuclear Power Plant concept enveloping suitable soil conditions. For the SSI analyses, SASSI program which adopts the Flexible Volume Method is used. In the SSI analyses, there can be uncertainties by Bond and De-bond problem between the structure and lateral soil elements. According to ASCE Standard 4, one method to address this concern is to assume no connectivity between structure and lateral soil over the upper half of the embedment of 20 ft (6 m), whichever is less. This study is performed as a part of the parametric analyses for the APR1400 seismic analyses to address the concern of the potential embedment effect on the in-structure response spectra due to connectivity between structure and lateral soil. In this study, 4 model cases are analyzed to check the potential embedment effect - Full connection, 20 ft no connectivity which is defined as a minimum De-bond depth of the soil in ASCE Standard 4 and 26.5 ft no connectivity between structure and lateral soil over the upper half of the embedment. Last one is full no connection for only reference. The in-structure response spectra are compared with the response spectra without considering the embedment effect. (authors)

Earliness-tardiness scheduling around almost equal due dates

NARCIS (Netherlands)

Hoogeveen, J.A.; Velde, van de S.L.

1997-01-01

The just-in-time concept in manufacturing has aroused interest in machine scheduling problems with earliness-tardiness penalties. In particular, common due date problems, which are structurally less complicated than problems with general due dates, have emerged as an interesting and fruitful field

The Effects of Dietary Macronutrient Balance on Skin Structure in Aging Male and Female Mice

Science.gov (United States)

McMahon, Aisling C.; Ruohonen, Kari; Raubenheimer, David; Ballard, J. William O.; Le Couteur, David G.; Nicholls, Caroline; Li, Zhe; Maitz, Peter K. M.; Wang, Yiwei; Simpson, Stephen J.

2016-01-01

Nutrition influences skin structure; however, a systematic investigation into how energy and macronutrients (protein, carbohydrate and fat) affects the skin has yet to be conducted. We evaluated the associations between macronutrients, energy intake and skin structure in mice fed 25 experimental diets and a control diet for 15 months using the Geometric Framework, a novel method of nutritional analysis. Skin structure was associated with the ratio of dietary macronutrients eaten, not energy intake, and the nature of the effect differed between the sexes. In males, skin structure was primarily associated with protein intake, whereas in females carbohydrate intake was the primary correlate. In both sexes, the dermis and subcutaneous fat thicknesses were inversely proportional. Subcutaneous fat thickness varied positively with fat intake, due to enlarged adipocytes rather than increased adipocyte number. We therefore demonstrated clear interactions between skin structure and macronutrient intakes, with the associations being sex-specific and dependent on dietary macronutrient balance. PMID:27832138

New rheological model for concrete structural analysis

International Nuclear Information System (INIS)

Chern, J.C.

1984-01-01

Long time deformation is of interest in estimating stresses of the prestressed concrete reactor vessel, in predicting cracking due to shrinkage or thermal dilatation, and in the design of leak-tight structures. Many interacting influences exist among creep, shrinkage and cracking for concrete. An interaction which researchers have long observed, is that at simultaneous drying and loading, the deformation of a concrete structure under the combined effect is larger than the sum of the shrinkage deformation of the structure at no load and the deformation of the sealed structure. The excess deformation due to the difference between observed test data and conventional analysis is regarded as the Pickett Effect. A constitutive relation explaining the Pickett Effect and other similar superposition problems, which includes creep, shrinkage (or thermal dilation), cracking, aging was developed with an efficient time-step numerical algorithm. The total deformation in the analysis is the sum of strain due to elastic deformation and creep, cracking and shrinkage with thermal dilatation. Instead of a sudden stress reduction to zero after the attainment of the strength limit, the gradual strain-softening of concrete (a gradual decline of stress at increasing strain) is considered

The heat treatment effect on the structural changes and properties of high-nitrogen chromium steels

International Nuclear Information System (INIS)

Blinov, V.M.; Elistratov, A.A.; Kolesnikov, A.G.; Rakhshtadt, A.G.; Plokhikh, A.I.; Morozova, E.I.; Kostina, M.V.

2000-01-01

The structural transformations in the steels with 0.4-1.3 %N and 15-24 %Cr content, originating by thermal treatment, are studied. The dependences of the phase composition of the high-chromium steels (18 %Cr) on the nitrogen content are established. The ratio of the unchanged austenite increases and the martensite quantity decreases correspondingly with growth of the nitrogen concentration from 0.4 up to 1.2 %. The effect of strengthening the steels with the initial martensite structure as well as austenite and martensite steels is observed in the process of steels tempering due to the hardening on the account of the martensite dispersion hardening [ru

Upright nanopyramid structured cover glass with light harvesting and self-cleaning effects for solar cell applications

International Nuclear Information System (INIS)

Amalathas, Amalraj Peter; Alkaisi, Maan M

2016-01-01

In this paper, we demonstrate the effect of upright nanopyramid (UNP) structured cover glass with light harvesting and self-cleaning functions on the device performance of monocrystalline Si solar cells. The UNP structures were fabricated on the surface of the glass substrate by simple, high throughput and low cost UV nanoimprint lithography, using a Si master mold with inverted nanopyramid (INP) structures. The diffuse transmittance and haze ratio values were significantly increased for UNP patterned glass, especially in the wavelength range 300–600 nm compared to the bare glass; this implies that antireflection and strong light scattering are due to the UNP structures. By replacing a bare cover glass with UNP patterned glass, the power conversion efficiency of the monocrystalline Si solar cell was substantially enhanced by about 10.97%; this is mainly due to the increased short-circuit current density J SC of 32.39 mA cm −2 compared to the reference cell with bare cover glass (i.e. J SC   =  31.60 mA cm −2 ). In addition, unlike the bare cover glass (i.e. θ CA ∼ 36°), the fluorinated UNP structured cover glass exhibited a hydrophobic surface with a water contact angle ( θ CA ) of ∼132° and excellent self-cleaning of dust particles by rolling down water droplets. (paper)

EFFECTIVE HYPERFINE-STRUCTURE FUNCTIONS OF AMMONIA

Energy Technology Data Exchange (ETDEWEB)

Augustovičová, L.; Soldán, P.; Špirko, V., E-mail: spirko@marge.uochb.cas.cz [Charles University in Prague, Faculty of Mathematics and Physics, Department of Chemical Physics and Optics, Ke Karlovu 3, CZ-12116 Prague 2 (Czech Republic)

2016-06-20

The hyperfine structure of the rotation-inversion ( v {sub 2} = 0{sup +}, 0{sup −}, 1{sup +}, 1{sup −}) states of the {sup 14}NH{sub 3} and {sup 15}NH{sub 3} ammonia isotopomers is rationalized in terms of effective (ro-inversional) hyperfine-structure (hfs) functions. These are determined by fitting to available experimental data using the Hougen’s effective hyperfine-structure Hamiltonian within the framework of the non-rigid inverter theory. Involving only a moderate number of mass independent fitting parameters, the fitted hfs functions provide a fairly close reproduction of a large majority of available experimental data, thus evidencing adequacy of these functions for reliable prediction. In future experiments, this may help us derive spectroscopic constants of observed inversion and rotation-inversion transitions deperturbed from hyperfine effects. The deperturbed band centers of ammonia come to the forefront of fundamental physics especially as the probes of a variable proton-to-electron mass ratio.

Effect of space structures against development of transport infrastructure in Banda Aceh by using the concept of transit oriented development

Science.gov (United States)

Noer, Fadhly; Matondang, A. Rahim; Sirojuzilam, Saleh, Sofyan M.

2017-11-01

Due to the shifting of city urban development causing the shift of city services center, so there is a change in space pattern and space structure in Banda Aceh, then resulting urban sprawl which can lead to congestion problem occurs on the arterial road in Banda Aceh, it can be seen from the increasing number of vehicles per year by 6%. Another issue occurs by urban sprawl is not well organized of settlement due to the uncontrolled use of space so that caused grouping or the differences in socioeconomic strata that can impact to the complexity of population mobility problem. From this background problem considered to be solved by a concept that is Transit Oriented Development (TOD), that is a concept of transportation development in co-operation with spatial. This research will get the model of transportation infrastructure development with TOD concept that can handle transportation problem in Banda Aceh, due to change of spatial structure, and to find whether TOD concept can use for the area that has a population in medium density range. The result that is obtained equation so the space structure is: Space Structure = 0.520 + 0.206X3 + 0.264X6 + 0.100X7 and Transportation Infrastructure Development = -1.457 + 0.652X1 + 0.388X5 + 0.235X6 + 0.222X7 + 0.327X8, So results obtained with path analysis method obtained variable influences, node ratio, network connectivity, travel frequency, travel destination, travel cost, and travel time, it has a lower value when direct effect with transportation infrastructure development, but if the indirect effect through the structure of space has a greater influence, can be seen from spatial structure path scheme - transportation infrastructure development.

Internal electric fields due to piezoelectric and spontaneous polarizations in CdZnO/MgZnO quantum well with various applied electric field effects

International Nuclear Information System (INIS)

Jeon, H.C.; Lee, S.J.; Kang, T.W.; Park, S.H.

2012-01-01

The strain-induced piezoelectric polarization and the spontaneous polarization can be reduced effectively using the applied electric field in the CdZnO/ZnMgO quantum well (QW) structure with high Cd composition. That is, optical properties as a function of internal and external fields in the CdZnO/ZnMgO QW with various applied electric field result in the increased optical gain due to the fact that the QW potential profile is flattened as a result of the compensation of the internal field by the reverse field as confirmed. These results demonstrate that a high-performance optical device operation can be realized in CdZnO/MgZnO QW structures by reducing the droop phenomenon.

Internal electric fields due to piezoelectric and spontaneous polarizations in CdZnO/MgZnO quantum well with various applied electric field effects

Energy Technology Data Exchange (ETDEWEB)

Jeon, H.C. [Quantum-functional Semiconductor Research Center, Dongguk University, Seoul 100-715 (Korea, Republic of); Lee, S.J., E-mail: leesj@dongguk.edu [Quantum-functional Semiconductor Research Center, Dongguk University, Seoul 100-715 (Korea, Republic of); Kang, T.W. [Quantum-functional Semiconductor Research Center, Dongguk University, Seoul 100-715 (Korea, Republic of); Park, S.H. [Department of Electronics Engineering, Catholic University of Daegu, Kyeongbuk 712-702 (Korea, Republic of)

2012-05-15

The strain-induced piezoelectric polarization and the spontaneous polarization can be reduced effectively using the applied electric field in the CdZnO/ZnMgO quantum well (QW) structure with high Cd composition. That is, optical properties as a function of internal and external fields in the CdZnO/ZnMgO QW with various applied electric field result in the increased optical gain due to the fact that the QW potential profile is flattened as a result of the compensation of the internal field by the reverse field as confirmed. These results demonstrate that a high-performance optical device operation can be realized in CdZnO/MgZnO QW structures by reducing the droop phenomenon.

Assessment of the structural brain network reveals altered connectivity in children with unilateral cerebral palsy due to periventricular white matter lesions

Directory of Open Access Journals (Sweden)

Kerstin Pannek

2014-01-01

Conclusion: This study shows that network-based analysis of structural connectivity can identify alterations in FA in unilateral CP, and that these alterations in FA are related to clinical function. Application of this connectome-based analysis to investigate alterations in connectivity following treatment may elucidate the neurological correlates of improved functioning due to intervention.

Optical nonlinearity due to thermomechanical effect in the planar and homeotropic nematic liquid crystals

Energy Technology Data Exchange (ETDEWEB)

Poursamad, J.B. [Physics & Optic Engineering Group, University of Bonab, Bonab (Iran, Islamic Republic of); Phirouznia, A. [Department of Physics, Azerbaijan ShahidMadani University, 53714-161 Tabriz (Iran, Islamic Republic of); Sahrai, M. [Research Institue for Applied Physics and Astronomy, Univerity of Tabriz, Tabriz (Iran, Islamic Republic of)

2015-11-01

Possibility of observing third thermomechanical (TM) effect in uniform nematic liquid crystals (NLC) with proper selection of boundary conditions on the cell walls is theoretically studied. Absorption of a light wave induces the needed temperature gradient for the TM effect. The molecular director reorientation due to third TM effect and the induced phase shift on the probe beam are calculated. The forth TM coefficient can be measured directly by the method proposed in this work.

Effect of Long-Period Ordering of the Structure of a Plant on the Initial Stages of Photosynthesis

Science.gov (United States)

Korshunov, M. A.; Shabanov, A. V.; Bukhanov, E. R.; Shabanov, V. F.

2018-01-01

Using data on the structure of plant leaves, specific features of light propagation in biophotoniccrystal structures have been established by the transfer matrix method. Splitting of the stopband in two bands has been found. The density of photonic states and the electromagnetic field value have been calculated. The occurrence of two photosystems (splitting of the stopband in two bands), the peculiarity of the long-wavelength quantum yield and its enhancement (Emerson effect), and water dissociation in the soft mode due to an increase in the electromagnetic field on the layers are explained.

The effects of ultrasonic pretreatment and structural changes during the osmotic dehydration of the 'Starking' apple (Malus domestica Borkh)

Energy Technology Data Exchange (ETDEWEB)

Rosa-Mendoza, M. E.; Fernandez-Munoz, J. L.; Arjona-Roman, J. L.

2012-11-01

During the osmotic dehydration (OD) of fruit, the cell membrane displays a high resistance to mass transfer, thereby reducing the dehydration rate. To reduce thermal damage to cell membranes, alternative methods have recently been introduced to reduce the initial moisture content and/or modify the structure of fruit tissue. The aim of this work was to evaluate the effects of an ultrasound (US) pretreatment for OD on the effective diffusion coefficients and to observe the changes in the molecular structure of 'Starking' apple cubes by Fourier-transform infrared spectroscopy (FTIR) during a 3 h process using a 45 dregee Bx sucrose solution at 60 degree centigrade. In the pretreatment step, apple samples were immersed in an ultrasonic bath at 45 kHz for 20 min. The effective diffusion coefficients for water (Dew) and solids (Des) were calculated from the observed osmotic kinetics according to Fick's second law for the transient state. The solids coefficients were higher than the water coefficients in both processes due to the concentration difference (De = 7.7 × 10{sup -}9 and 9.7 × 10{sup -}9 m{sup 2} s{sup -}1 for ODUS). The structural changes were determined by FTIR by measuring the molecular vibration frequency for sucrose. The 1,500-900 cm{sup -}1 region of the infrared spectra was used to monitor the effect of sucrose concentration on fruit structure. We observed that the first bonds formed were C-H and C-O-C stretching (at 920 and 1,129 cm{sup -}1, respectively) in the sucrose skeleton and glycoside bonds among sucrose molecules. The water concentration affected the diffusion coefficient significantly due to its dependence on the physical structure of the food. (Author) 27 refs.

Solvent effects on the crystal growth structure and morphology of the pharmaceutical dirithromycin

Science.gov (United States)

Wang, Yuan; Liang, Zuozhong

2017-12-01

Solvent effects on the crystal structure and morphology of pharmaceutical dirithromycin molecules were systematically investigated using both experimental crystallization and theoretical simulation. Dirithromycin is one of the new generation of macrolide antibiotics with two polymorphic forms (Form I and Form II) and many solvate forms. Herein, six solvates of the dirithromycin, including acetonitrile, acetonitrile/water, acetone, 1-propanol, N,N-dimethylformamide (DMF) and cyclohexane, were studied. Experimentally, we crystallized the dirithromycin molecules in different solvents by the solvent evaporating method and measured the crystal structures with the X-ray diffraction (XRD). We compared these crystal structures of dirithromycin solvates and analyzed the solvent property-determined structure evolution. The solvents have a strong interaction with the dirithromycin molecule due to the formation of inter-molecular interactions (such as the hydrogen bonding and close contacts (sum of vdW radii)). Theoretically, we calculated the ideal crystal habit based on the solvated structures with the attachment growth (AE) model. The predicted morphologies and aspect ratios of dirithromycin solvates agree well with the experimental results. This work could be helpful to better understand the structure and morphology evolution of solvates controlled by solvents and guide the crystallization of active pharmaceutical ingredients in the pharmaceutical industry.

Effective mass and damping of submerged structures

International Nuclear Information System (INIS)

Dong, R.G.

1978-01-01

Various structures important for safety in nuclear power plants must remain functioning in the event of an earthquake or other dynamic phenomenon. Some of these important structures, such as spent-fuel storage racks, main pressure-relief valve lines, and internal structures in the reactor vessel, are submerged in water. Dynamic analysis must include the force and damping effects of water. This report provides a technical basis for evaluating the wide variety of modeling assumptions currently used in design analysis. Current design analysis techniques and information in the literature form the basis of our conclusions and recommendations. We surveyed 32 industrial firms and reviewed 49 technical references. We compare various theories with published experimental results wherever possible. Our findings generally pertain to idealized structures, such as single isolated members, arrays of members, and coaxial cylinders. We relate these findings to the actual reactor structures through observations and recommendations. Whenever possible we recommend a definite way to evaluate the effect of hydrodynamic forces on these structures

Estimation of organ and effective dose due to Compton backscatter security scans

International Nuclear Information System (INIS)

Hoppe, Michael E.; Schmidt, Taly Gilat

2012-01-01

Purpose: To estimate organ and effective radiation doses due to backscatter security scanners using Monte Carlo simulations and a voxelized phantom set. Methods: Voxelized phantoms of male and female adults and children were used with the GEANT4 toolkit to simulate a backscatter security scan. The backscatter system was modeled based on specifications available in the literature. The simulations modeled a 50 kVp spectrum with 1.0 mm-aluminum-equivalent filtration and a previously measured exposure of approximately 4.6 μR at 30 cm from the source. Photons and secondary interactions were tracked from the source until they reached zero kinetic energy or exited from the simulation’s boundaries. The energy deposited in the phantoms’ respective organs was tallied and used to calculate total organ dose and total effective dose for frontal, rear, and full scans with subjects located 30 and 75 cm from the source. Results: For a full screen, all phantoms’ total effective doses were below the established 0.25 μSv standard, with an estimated maximum total effective dose of 0.07 μSv for full screen of a male child. The estimated maximum organ dose due to a full screen was 1.03 μGy, deposited in the adipose tissue of the male child phantom when located 30 cm from the source. All organ dose estimates had a coefficient of variation of less than 3% for a frontal scan and less than 11% for a rear scan. Conclusions: Backscatter security scanners deposit dose in organs beyond the skin. The effective dose is below recommended standards set by the Health Physics Society (HPS) and the American National Standards Institute (ANSI) assuming the system provides a maximum exposure of approximately 4.6 μR at 30 cm.

The effects of structure anisotropy on lensing observables in an exact general relativistic setting for precision cosmology

Energy Technology Data Exchange (ETDEWEB)

Troxel, M. A.; Ishak, Mustapha; Peel, Austin, E-mail: troxel@utdallas.edu, E-mail: mishak@utdallas.edu, E-mail: austin.peel@utdallas.edu [Department of Physics, The University of Texas at Dallas, Richardson, TX 75080 (United States)

2014-03-01

The study of relativistic, higher order, and nonlinear effects has become necessary in recent years in the pursuit of precision cosmology. We develop and apply here a framework to study gravitational lensing in exact models in general relativity that are not restricted to homogeneity and isotropy, and where full nonlinearity and relativistic effects are thus naturally included. We apply the framework to a specific, anisotropic galaxy cluster model which is based on a modified NFW halo density profile and described by the Szekeres metric. We examine the effects of increasing levels of anisotropy in the galaxy cluster on lensing observables like the convergence and shear for various lensing geometries, finding a strong nonlinear response in both the convergence and shear for rays passing through anisotropic regions of the cluster. Deviation from the expected values in a spherically symmetric structure are asymmetric with respect to path direction and thus will persist as a statistical effect when averaged over some ensemble of such clusters. The resulting relative difference in various geometries can be as large as approximately 2%, 8%, and 24% in the measure of convergence (1−κ) for levels of anisotropy of 5%, 10%, and 15%, respectively, as a fraction of total cluster mass. For the total magnitude of shear, the relative difference can grow near the center of the structure to be as large as 15%, 32%, and 44% for the same levels of anisotropy, averaged over the two extreme geometries. The convergence is impacted most strongly for rays which pass in directions along the axis of maximum dipole anisotropy in the structure, while the shear is most strongly impacted for rays which pass in directions orthogonal to this axis, as expected. The rich features found in the lensing signal due to anisotropic substructure are nearly entirely lost when one treats the cluster in the traditional FLRW lensing framework. These effects due to anisotropic structures are thus likely to

The effect of promoters on the electronic structure of ruthenium catalysts supported on carbon

International Nuclear Information System (INIS)

Guraya, Monica; Sprenger, Susanne; Rarog-Pilecka, Wioletta; Szmigiel, Dariusz; Kowalczyk, Zbigniew; Muhler, Martin

2004-01-01

Alkali- and earth-alkali-promoted ruthenium catalysts supported on graphitized carbon were investigated by means of X-ray and ultraviolet photoelectron spectroscopy (XPS and UPS) in order to study the effect of promoters on the electronic structure of this metal-support system. Samples were measured as prepared and after thorough reduction in hydrogen. The C 1s spectra of reduced alkali-promoted catalysts showed a shift towards higher binding energies and an asymmetric broadening. Neither non-promoted nor Ba-promoted Ru/C samples exhibited such a behaviour after similar treatments. The most important feature in the UP spectra of the reduced alkali-promoted catalysts was the appearance of a well defined Fermi edge absent in the semimetal-like electronic structure of graphite. No significant effects appeared in the case of non-promoted or Ba-promoted catalysts. The increase in the density of occupied states at the Fermi energy indicates a shift of this level into the conduction band, due to a charge transfer from the promoter to the support. This interpretation also provides an explanation for the observed higher C 1s binding energy and asymmetric broadening, due to the off-set introduced in the binding energy scale and the increasing probability of inelastic excitations near the Fermi level. In addition to photoelectron spectroscopy, low energy ion scattering (ISS) was used to obtain information about the localisation of the promoters. Based on the mild sputtering effect during prolonged series of spectra, it was possible to conclude that potassium covers both the carbon support and the Ru metal particles

Effects prediction guidelines for structures subjected to ground motion

International Nuclear Information System (INIS)

1975-07-01

Part of the planning for an underground nuclear explosion (UNE) is determining the effects of expected ground motion on exposed structures. Because of the many types of structures and the wide variation in ground motion intensity typically encountered, no single prediction method is both adequate and feasible for a complete evaluation. Furthermore, the nature and variability of ground motion and structure damage prescribe effects predictions that are made probabilistically. Initially, prediction for a UNE involves a preliminary assessment of damage to establish overall project feasibility. Subsequent efforts require more detailed damage evaluations, based on structure inventories and analyses of specific structures, so that safety problems can be identified and safety and remedial measures can be recommended. To cover this broad range of effects prediction needs for a typical UNE project, three distinct but interrelated methods have been developed and are described. First, the fundamental practical and theoretical aspects of predicting the effects of dynamic ground motion on structures are summarized. Next, experimentally derived and theoretically determined observations of the behavior of typical structures subjected to ground motion are presented. Then, based on these fundamental considerations and on the observed behavior of structures, the formulation of the three effects prediction procedures is described, along with guidelines regarding their applicability. Example damage predictions for hypothetical UNEs demonstrate these procedures. To aid in identifying the vibration properties of complex structures, one chapter discusses alternatives in vibration testing, instrumentation, and data analysis. Finally, operational guidelines regarding data acquisition procedures, safety criteria, and remedial measures involved in conducting structure effects evaluations are discussed. (U.S.)

Voltabsorptometric study of 'structural memory' effects in polyaniline

International Nuclear Information System (INIS)

Nekrasov, A.A.; Ivanov, V.F.; Gribkova, O.L.; Vannikov, A.V.

2005-01-01

This study is aimed at clarifying the role of the counter anions used in the electrochemical synthesis of polyaniline (PAn) on the spectroelectrochemical properties of the resulting film (so-called ''structural memory'' effect). Polyaniline films were synthesized in aqueous solutions of different acids: HCl, HClO 4 and H 2 SO 4 ('parent' acids). Further spectroelectrochemical studies were performed in aqueous solutions of the above-mentioned acids for each of the films synthesized in the above 'parent' acids. Differential voltabsorptometric curves (dA/dt versus potential (DCVA)) were measured at certain characteristic wavelengths corresponding to the individual absorption bands separated from the spectra using Alentsev-Fock method. These are the bands of the radical cations (435 nm), quinoid fragments (570 nm), dimers of radical cations (presumably 665 nm) and 'localized polarons' (755 nm). Particular attention has been paid to the formation of the dimers of radical cations and their role in the redox transitions in the film. Comparing our results with the literature data, we suppose that such dimers may facilitate electron exchange between adjacent polymer chains contributing to the conductivity increase. Complex nature of the first voltammetric peak was discovered, which is probably due to the heterogeneous structure of PAn. Results of molecular modeling of the interchain dimers of the radical cations using semi-empirical PM3 calculations are reported and their electronic spectrum was simulated

Effect of Different Structural Materials on Neutronic Performance of a Hybrid Reactor

Science.gov (United States)

Übeyli, Mustafa; Tel, Eyyüp

2003-06-01

Selection of structural material for a fusion-fission (hybrid) reactor is very important by taking into account of neutronic performance of the blanket. Refractory metals and alloys have much higher operating temperatures and neutron wall load (NWL) capabilities than low activation materials (ferritic/martensitic steels, vanadium alloys and SiC/SiC composites) and austenitic stainless steels. In this study, effect of primary candidate refractory alloys, namely, W-5Re, T111, TZM and Nb-1Zr on neutronic performance of the hybrid reactor was investigated. Neutron transport calculations were conducted with the help of SCALE 4.3 System by solving the Boltzmann transport equation with code XSDRNPM. Among the investigated structural materials, tantalum had the worst performance due to the fact that it has higher neutron absorption cross section than others. And W-5Re and TZM having similar results showed the best performance.

Plant Sterols: Chemical and Enzymatic Structural Modifications and Effects on Their Cholesterol-Lowering Activity.

Science.gov (United States)

He, Wen-Sen; Zhu, Hanyue; Chen, Zhen-Yu

2018-03-28

Plant sterols have attracted increasing attention due to their excellent cholesterol-lowering activity. However, free plant sterols have some characteristics of low oil solubility, water insolubility, high melting point, and low bioavailability, which greatly limit their application in foods. Numerous studies have been undertaken to modify their chemical structures to improve their chemical and physical properties in meeting the needs of various applications. The present review is to summarize the literature and update the progress on structural modifications of plant sterols in the following aspects: (i) synthesis of plant sterol esters by esterification and transesterification with hydrophobic fatty acids and triacylglycerols to improve their oil solubility, (ii) synthesis of plant sterol derivatives by coupling with various hydrophilic moieties to enhance their water solubility, and (iii) mechanisms by which plant sterols reduce plasma cholesterol and the effect of structural modifications on plasma cholesterol-lowering activity of plant sterols.

BENDING THE DOMING EFFECT IN STRUCTURE FROM MOTION RECONSTRUCTIONS THROUGH BUNDLE ADJUSTMENT

Directory of Open Access Journals (Sweden)

L. Magri

2017-08-01

Full Text Available Structure from Motion techniques provides low-cost and flexible methods that can be adopted in arial surveying to collect topographic data with accurate results. Nevertheless, the so-called “doming effect”, due to unfortunate acquisition conditions or unreliable modeling of radial distortion, has been recognized as a critical issue that disrupts the quality of the attained 3D reconstruction. In this paper we propose a novel method, that works effectively in the presence of a nearly flat soil, to tackle a posteriori the doming effect: an automatic ground detection method is used to capture the doming deformation flawing the reconstruction, which in turn is wrapped to the correct geometry by iteratively enforcing a planarity constraint through a Bundle Adjustment framework. Experiments on real word datasets demonstrate promising results.

Diplopia due to Dacryops

Directory of Open Access Journals (Sweden)

Rahmi Duman

2013-01-01

Full Text Available Dacryops is a lacrimal ductal cyst. It is known that it can cause globe displacement, motility restriction, and proptosis because of the mass effect. Diplopia due to dacryops has not been reported previously. Here, we present a 57-year-old man with binocular horizontal diplopia that occurred during left direction gaze due to dacryops.

Effective equations for fluid-structure interaction with applications to poroelasticity

KAUST Repository

Brown, Donald; Popov, Peter V.; Efendiev, Yalchin R.

2012-01-01

Modeling of fluid-solid interactions in porous media is a challenging and computationally demanding task. Due to the multiscale nature of the problem, simulating the flow and mechanics by direct numerical simulation is often not feasible and an effective model is preferred. In this work, we formally derive an effective model for Fluid-Structure Interaction (FSI). In earlier work, assuming infinitesimal pore-scale deformations, an effective poroelastic model of Biot was derived. We extend this model to a nonlinear Biot model that includes pore-scale deformation into the effective description. The main challenge is the difference in coordinate systems of the fluid and solid equations. This is circumvented by utilizing the Arbitrary Lagrange-Eulerian (ALE) formulation of the FSI equations, giving a unified frame in which to apply two-scale asymptotic techniques. In the derived nonlinear Biot model, the local cell problem are coupled to the macroscopic equations via the effective coefficients. These coefficients may be viewed as tabular functions of the macroscopic parameters. After simplifying this dependence, we assume the coefficients depend on macroscopic pressure only. Using a three dimensional pore geometry we calculate, as a proof-of-concept example, the effective permeability and Biot coefficients for various values or pressure. We observe that, for this geometry, a stronger pressure dependence on flow quantities than on mechanically based effective quantities. © 2014 Taylor & Francis Group, LLC.

Effective equations for fluid-structure interaction with applications to poroelasticity

KAUST Repository

Brown, Donald

2012-11-05

Modeling of fluid-solid interactions in porous media is a challenging and computationally demanding task. Due to the multiscale nature of the problem, simulating the flow and mechanics by direct numerical simulation is often not feasible and an effective model is preferred. In this work, we formally derive an effective model for Fluid-Structure Interaction (FSI). In earlier work, assuming infinitesimal pore-scale deformations, an effective poroelastic model of Biot was derived. We extend this model to a nonlinear Biot model that includes pore-scale deformation into the effective description. The main challenge is the difference in coordinate systems of the fluid and solid equations. This is circumvented by utilizing the Arbitrary Lagrange-Eulerian (ALE) formulation of the FSI equations, giving a unified frame in which to apply two-scale asymptotic techniques. In the derived nonlinear Biot model, the local cell problem are coupled to the macroscopic equations via the effective coefficients. These coefficients may be viewed as tabular functions of the macroscopic parameters. After simplifying this dependence, we assume the coefficients depend on macroscopic pressure only. Using a three dimensional pore geometry we calculate, as a proof-of-concept example, the effective permeability and Biot coefficients for various values or pressure. We observe that, for this geometry, a stronger pressure dependence on flow quantities than on mechanically based effective quantities. © 2014 Taylor & Francis Group, LLC.

Quantifying Ancient Maya Land Use Legacy Effects on Contemporary Rainforest Canopy Structure

Directory of Open Access Journals (Sweden)

Jessica N. Hightower

2014-11-01

Full Text Available Human land use legacies have significant and long-lasting ecological impacts across landscapes. Investigating ancient (>400 years legacy effects can be problematic due to the difficulty in detecting specific, historic land uses, especially those hidden beneath dense canopies. Caracol, the largest (~200 km2 Maya archaeological site in Belize, was abandoned ca. A.D. 900, leaving behind myriad structures, causeways, and an extensive network of agricultural terraces that persist beneath the architecturally complex tropical forest canopy. Airborne LiDAR enables the detection of these below-canopy archaeological features while simultaneously providing a detailed record of the aboveground 3-dimensional canopy organization, which is indicative of a forest’s ecological function. Here, this remote sensing technology is used to determine the effects of ancient land use legacies on contemporary forest structure. Canopy morphology was assessed by extracting LiDAR point clouds (0.25 ha plots from LiDAR-identified terraced (n = 150 and non-terraced (n = 150 areas on low (0°–10°, medium (10°–20°, and high (>20° slopes. We calculated the average canopy height, canopy openness, and vertical diversity from the LiDAR returns, with topographic features (i.e., slope, elevation, and aspect as covariates. Using a PerMANOVA procedure, we determined that forests growing on agricultural terraces exhibited significantly different canopy structure from those growing on non-terraced land. Terraces appear to mediate the effect of slope, resulting in less structural variation between slope and non-sloped land and yielding taller, more closed, more vertically diverse forests. These human land uses abandoned >1000 years ago continue to impact contemporary tropical rainforests having implications related to arboreal habitat and carbon storage.

Structural Response to Blast Loading: The Effects of Corrosion on Reinforced Concrete Structures

Directory of Open Access Journals (Sweden)

Hakan Yalciner

2014-01-01

Full Text Available Structural blast design has become a necessary part of the design with increasing terrorist attacks. Terrorist attacks are not the one to make the structures important against blast loading where other explosions such as high gas explosions also take an important place in structural safety. The main objective of this study was to verify the structural performance levels under the impact of different blast loading scenarios. The blast loads were represented by using triangular pulse for single degree of freedom system. The effect of blast load on both corroded and uncorroded reinforced concrete buildings was examined for different explosion distances. Modified plastic hinge properties were used to ensure the effects of corrosion. The results indicated that explosion distance and concrete strength were key parameters to define the performance of the structures against blast loading.

Effect of Additional Structure on Effective Stack Height of Gas Dispersion in Atmosphere

OpenAIRE

Takenobu Michioka; Koichi Sada; Kazuki Okabayashi

2016-01-01

Wind-tunnel experiments were conducted to evaluate the effect of additional structure (building, sea wall and banking) on the effective stack height, which is usually used in safety analyses of nuclear power facilities in Japan. The effective stack heights were estimated with and without the additional structure in addition to the reactor building while varying several conditions such as the source height, the height of additional structure and the distance between the source position and the...

Modelling Variable Fire Severity in Boreal Forests: Effects of Fire Intensity and Stand Structure.

Science.gov (United States)

Miquelajauregui, Yosune; Cumming, Steven G; Gauthier, Sylvie

2016-01-01

It is becoming clear that fires in boreal forests are not uniformly stand-replacing. On the contrary, marked variation in fire severity, measured as tree mortality, has been found both within and among individual fires. It is important to understand the conditions under which this variation can arise. We integrated forest sample plot data, tree allometries and historical forest fire records within a diameter class-structured model of 1.0 ha patches of mono-specific black spruce and jack pine stands in northern Québec, Canada. The model accounts for crown fire initiation and vertical spread into the canopy. It uses empirical relations between fire intensity, scorch height, the percent of crown scorched and tree mortality to simulate fire severity, specifically the percent reduction in patch basal area due to fire-caused mortality. A random forest and a regression tree analysis of a large random sample of simulated fires were used to test for an effect of fireline intensity, stand structure, species composition and pyrogeographic regions on resultant severity. Severity increased with intensity and was lower for jack pine stands. The proportion of simulated fires that burned at high severity (e.g. >75% reduction in patch basal area) was 0.80 for black spruce and 0.11 for jack pine. We identified thresholds in intensity below which there was a marked sensitivity of simulated fire severity to stand structure, and to interactions between intensity and structure. We found no evidence for a residual effect of pyrogeographic region on simulated severity, after the effects of stand structure and species composition were accounted for. The model presented here was able to produce variation in fire severity under a range of fire intensity conditions. This suggests that variation in stand structure is one of the factors causing the observed variation in boreal fire severity.

Bounds on the Effect of Progressive Structural Degradation

DEFF Research Database (Denmark)

Achtziger, W.; Bendsøe, Martin P; Taylor, John E.

1998-01-01

Problem formulations are presented for the evaluation of upper and lower bounds on the effect of progressive structural degradation. For the purposes of this study, degradation effect is measured by an increase in global structural compliance (flexibility). Thus the slated bounds are given simply...

Bounds on the Effect of Progressive Structural Degradation

DEFF Research Database (Denmark)

Achtziger, Wolfgang; Bendsøe, Martin P; Taylor, John E.

1997-01-01

Problem formulations are presented for the evaluation of upper and lower bounds on the effect of progressive structural degradation. For the purposes of this study, degradation effect is measured by an increase in global structural compliance (flexibility). Thus the stated bounds are given simply...

Irradiation deformation due to SIPA induced dislocation anisotropy

International Nuclear Information System (INIS)

Woo, CH.

1980-02-01

A contribution to irradiation deformation resulting from the stress-induced preferred adsorption (SIPA) effect is considered. SIPA causes a variation of the growth rates of irradiation-generated dislocation loops, according to the alignment of their Burgers vectors with respect to the applied stress. A prolinged period under an applied stress then creates an anisotropic dislocation structure in which the majority of dislocations have their Burgers vectors in alignment with the stress. In the presence of 'neutral' sinks, the resulting anisotropic dislocation structure causes plastic deformation similar to the way in which irradiation growth occurs in zirconium. This mechanism is called SIPA-induced growth (SIG). We have shown that SIG is very significant in comparison to SIPA, except when little or no loop growth has occurred during the period the stress is applied. This report contains the detailed formulation and derivation of the formulae for the evaluation of the contribution due to SIG. (auth)

Structural properties and neutron irradiation effects of ceramics

International Nuclear Information System (INIS)

Yano, Toyohiko

1994-01-01

In high temperature gas-cooled reactors and nuclear fusion reactors being developed at present, various ceramics are to be used in the environment of neutron irradiation for undertaking important functions. The change of the characteristics of those materials by neutron irradiation must be exactly forecast, but it has been known that the response of the materials is different respectively. The production method of ceramics and the resulted structures of ceramics which control their characteristics are explained. The features of covalent bond and ionic bond, the synthesis of powder and the phase change by heating, sintering and sintering agent, and grain boundary phase are described. The smelling of ceramics by neutron irradiation is caused by the formation of the clusters of Frenkel defects and minute spot defects. Its restoration by annealing is explained. The defects remaining in materials after irradiation are the physical defects by flipping atoms cut due to the collision with high energy particles and the chemical defects by nuclear transformation. Some physical defects can be restored, but chemical defects are never restored. The mechanical properties of ceramics and the effect of irradiation on them, and the thermal properties of ceramics and the effect of irradiation on them are reported. (K.I.)

Structure of the X-ray photoelectron spectra of fluorides and oxides of lanthanides connected with the dynamic effect

International Nuclear Information System (INIS)

Teterin, Yu.A.; Teterin, A.Yu.; Lebedev, A.M.; Utkin, I.O.; Nikitin, A.S.

1998-01-01

Impact of dynamic effect on the fine structure of the X-ray electron spectra of the lanthanide oxides and fluorides is considered. Significant complication of the Ln4p-electrons occurs due to interaction of configurations of the basic single-hole and additional two-hole finite states of the 4p 5 4d 10 4f n ↔ 4p 6 4d 8 4f n+1 type. Impact of the atoms nature of the nearest surrounding of the lanthanides ions on the parameters of such fine structure is evaluated [ru

Current bistability in a weakly coupled multi-quantum well structure: a magnetic field induced 'memory effect'

International Nuclear Information System (INIS)

Feu, W H M; Villas-Boas, J M; Cury, L A; Guimaraes, P S S; Vieira, G S; Tanaka, R Y; Passaro, A; Pires, M P; Landi, S M; Souza, P L

2009-01-01

A study of magnetotunnelling in weakly coupled multi-quantum wells reveals a new phenomenon which constitutes a kind of memory effect in the sense that the electrical resistance of the sample after application of the magnetic field is different from before and contains the information that a magnetic field was applied previously. The change in the electric field domain configuration triggered by the magnetic field was compared for two samples, one strictly periodic and another with a thicker quantum well inserted into the periodic structure. For applied biases at which two electric field domains are present in the sample, as the magnetic field is increased a succession of discontinuous reductions in the electrical resistance is observed due to the magnetic field-induced rearrangement of the electric field domains, i.e. the domain boundary jumps from well to well as the magnetic field is changed. The memory effect is revealed for the aperiodic structure as the electric field domain configuration triggered by the magnetic field remains stable after the field is reduced back to zero. This effect is related to the multi-stability in the current-voltage characteristics observed in some weakly coupled multi-quantum well structures.

Spin-torsion effects in the hyperfine structure of methanol

International Nuclear Information System (INIS)

Coudert, L. H.; Gutlé, C.; Huet, T. R.; Grabow, J.-U.; Levshakov, S. A.

2015-01-01

The magnetic hyperfine structure of the non-rigid methanol molecule is investigated experimentally and theoretically. 12 hyperfine patterns are recorded using molecular beam microwave spectrometers. These patterns, along with previously recorded ones, are analyzed in an attempt to evidence the effects of the magnetic spin-torsion coupling due to the large amplitude internal rotation of the methyl group [J. E. M. Heuvel and A. Dymanus, J. Mol. Spectrosc. 47, 363 (1973)]. The theoretical approach setup to analyze the observed data accounts for this spin-torsion in addition to the familiar magnetic spin-rotation and spin-spin interactions. The theoretical approach relies on symmetry considerations to build a hyperfine coupling Hamiltonian and spin-rotation-torsion wavefunctions compatible with the Pauli exclusion principle. Although all experimental hyperfine patterns are not fully resolved, the line position analysis yields values for several parameters including one describing the spin-torsion coupling

Graphite nanoplatelets-modified PLA/PCL: Effect of blend ratio and nanofiller localization on structure and properties.

Science.gov (United States)

Kelnar, Ivan; Kratochvíl, Jaroslav; Kaprálková, Ludmila; Zhigunov, Alexander; Nevoralová, Martina

2017-07-01

Structure and properties of poly(lactic acid) (PLA)/poly (ɛ-caprolactone) (PCL) influenced by graphite nanoplatelets (GNP) were studied in dependence on blend composition. Electron microscopy indicates predominant localization of GNP in PCL. GNP-induced changes in viscosity hinder refinement of PCL inclusions, support PCL continuity in the co-continuous system, and lead to reduction of PLA inclusions size without GNP being present at the interface in the PCL-matrix blend. Negligible differences in crystallinity of both phases indicate that mechanical behaviour is mainly influenced by reinforcement and GNP-induced changes in morphology. Addition of 5 parts of GNP leads to ~40% and ~25% increase of stiffness in the PCL- and PLA-matrix systems, respectively, whereas the reinforcing effect is practically eliminated in the co-continuous systems due to GNP-induced lower continuity of PLA which enhances toughness. Impact resistance of the 80/20 blend shows increase with 5 parts content due to synergistic effect of PCL/GNP stacks, whereas minor increase in the blend of the ductile PCL matrix with brittle PLA inclusions is caused by GNP-modification of the component parameters. Results indicate high potential of GNP in preparing biocompatible systems with wide range of structure and properties. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ergodization of magnetic surfaces due to finite beta effect in a helical system

International Nuclear Information System (INIS)

Hayashi, Takaya.

1989-04-01

Breaking of magnetic surfaces due to finite beta effect in a l=2 heliotron/torsatron configuration is studied by using a newly developed three dimensional equilibrium code. Breaking can be suppressed by a larger aspect ratio configuration, shaping of magnetic surface (inward shift or prolate shape), pitch modulation of helical coils, or pressure profile control. (author)

The effect of the water tariff structures on the water consumption in Mallorcan hotels

Science.gov (United States)

Deyà-Tortella, Bartolomé; Garcia, Celso; Nilsson, William; Tirado, Dolores

2016-08-01

Tourism increases water demand, especially in coastal areas and on islands, and can also cause water shortages during the dry season and the degradation of the water supply. The aim of this study is to evaluate the impact of water price structures on hotel water consumption on the island of Mallorca (Spain). All tourist municipalities on the island use different pricing structures, such as flat or block rates, and different tariffs. This exogenous variation is used to evaluate the effect of prices on water consumption for a sample of 134 hotels. The discontinuity of the water tariff structure and the fixed rate, which depends on the number of hotel beds, generate endogeneity problems. We propose an econometric model, an instrumental variable quantile regression for within artificial blocks transformed data, to solve both problems. The coefficients corresponding to the price variables are not found to be significantly different from zero. The sign of the effect is negative, but the magnitude is negligible: a 1% increase in all prices would reduce consumption by an average of only 0.024%. This result is probably due to the small share of water costs with respect to the total hotel operational costs (around 4%). Our regression model concludes that the introduction of water-saving initiatives constitutes an effective way to reduce consumption.

Exciting imperfection. Real-structure effects in magnesium-, cadmium-, and zinc-oxide

Energy Technology Data Exchange (ETDEWEB)

Schleife, Andre

2010-07-01

We employ recent ab-initio methods and theoretical spectroscopy techniques that rely on heavy numerical calculations to describe electronic excitations in non-ideal crystals of three group-II oxides. We study the ideal equilibrium polymorphs of these oxides, for gaining a thorough understanding as well as the necessary confidence in our approaches to generalize and apply them to the electronic excitations in imperfect crystals. As such imperfections we take the influence of strain, the alloying of the different oxides, an intrinsic point defect, and free electrons in the lowest conduction band into account. We employ the DFT results as input in order to compute quasiparticle electronic structures, which are in good agreement with experimental findings. According to Hedin's equations for interacting electrons, the electron-hole interaction is taken into account by solving a Bethe-Salpeter equation for the polarization function. Thereafter the equilibrium polymorphs of ideal bulk MgO, ZnO, and CdO and investigates the structure of their valence and conduction bands are described. We present densities of states and effective masses, as well as natural band discontinuities. Furthermore, our description of the dielectric function, which takes excitonic effects into account, enables us to derive the electron-energy loss function. The influence of uniaxial and biaxial strain on the ordering of the valence bands in ZnO is investigated. In addition, we explore the electronic band structure of the non-equilibrium wurtzite structures of MgO and CdO. We predict valence-band splittings and band gaps as they might occur at interfaces of Mgo or CdO with ZnO substrates. Thereafter we study pseudobinary alloys by means of a cluster expansion method. Due to the different crystal structures of the respective oxides, i.e. rocksalt and wurtzite, the description of their heterostructural combination has to be achieved. The electronic and optical properties of the group-II oxide

Exciting imperfection. Real-structure effects in magnesium-, cadmium-, and zinc-oxide

International Nuclear Information System (INIS)

Schleife, Andre

2010-01-01

We employ recent ab-initio methods and theoretical spectroscopy techniques that rely on heavy numerical calculations to describe electronic excitations in non-ideal crystals of three group-II oxides. We study the ideal equilibrium polymorphs of these oxides, for gaining a thorough understanding as well as the necessary confidence in our approaches to generalize and apply them to the electronic excitations in imperfect crystals. As such imperfections we take the influence of strain, the alloying of the different oxides, an intrinsic point defect, and free electrons in the lowest conduction band into account. We employ the DFT results as input in order to compute quasiparticle electronic structures, which are in good agreement with experimental findings. According to Hedin's equations for interacting electrons, the electron-hole interaction is taken into account by solving a Bethe-Salpeter equation for the polarization function. Thereafter the equilibrium polymorphs of ideal bulk MgO, ZnO, and CdO and investigates the structure of their valence and conduction bands are described. We present densities of states and effective masses, as well as natural band discontinuities. Furthermore, our description of the dielectric function, which takes excitonic effects into account, enables us to derive the electron-energy loss function. The influence of uniaxial and biaxial strain on the ordering of the valence bands in ZnO is investigated. In addition, we explore the electronic band structure of the non-equilibrium wurtzite structures of MgO and CdO. We predict valence-band splittings and band gaps as they might occur at interfaces of Mgo or CdO with ZnO substrates. Thereafter we study pseudobinary alloys by means of a cluster expansion method. Due to the different crystal structures of the respective oxides, i.e. rocksalt and wurtzite, the description of their heterostructural combination has to be achieved. The electronic and optical properties of the group-II oxide alloys

River channel morphology and hydraulics properties due to introduction of plant basket hydraulic structures for river channel management

Science.gov (United States)

Kałuża, Tomasz; Radecki-Pawlik, Artur; Plesiński, Karol; Walczak, Natalia; Szoszkiewicz, Krzysztof; Radecki-Pawlik, Bartosz

2016-04-01

In the present time integrated water management is directly connected with management and direct works in river channels themselves which are taking into account morphological processes in rivers and improve flow conditions. Our work focused on the hydraulic and hydrodynamic consequences upon the introduction of the concept of the improvement of the hydromorphological conditions of the Flinta River in a given reach following river channel management concept. Based on a comprehensive study of the hydromorphological state of the river, four sections were selected where restoration measures can efficiently improve river habitat conditions in the river. For each section a set of technical and biological measures were proposed and implemented in practice. One of the proposed solutions was to construct plant basket hydraulic structures (PBHS) within the river channel, which are essentially plant barriers working as sediment traps, changing river channel morphology and are in line with concepts of Water Framework Directive. These relatively small structures work as crested weirs and unquestionably change the channel morphology. Along our work we show the results of three-year long (2013-2015) systematic measurements that provided information on the morphological consequences of introducing such structures into a river channel. Our main conclusions are as follows: 1. Plant basket hydraulic structures cause changes in hydrodynamic conditions and result in sediment accumulation and the formation of river backwaters upstream and downstream the obstacle; 2. The introduced plant basket hydraulic structures cause plant debris accumulation which influences the hydrodynamic flow conditions; 3. The installation of plant basket hydraulic structures on the river bed changes flow pattern as well as flow hydrodynamic conditions causing river braiding process; 4. The erosion rate below the plant basket hydraulic structures is due to the hydraulic work conditions of the PBHS and its

Effects of input structural dates for displacements and internal forces of structures in case of earthquake

International Nuclear Information System (INIS)

Gyoergyi, J.

2001-01-01

This paper analyses the effects of uncertainties in the modulus of elasticity of the constructional material, soil stiffness and the mass of structure on models corresponding to two typical structures in the Paks Nuclear Power Plant. The structure has been modelled as a beam model, and in computation of soil springs, a stiff foundation has been taken into account. Analyses show that masses must be taken into account as correctly as possible, but the effects of soil stiffness are sharply different with flexible and rigid structures. This effect in the case of flexible buildings is less important than in the case of rigid-box-like structures. (author)

Local effects in thin elastic shell due to thermal and mechanical loadings

International Nuclear Information System (INIS)

Taheri, S.

1987-01-01

For a thick cylinder (1/15)<(h/rm)<(1/3) the local effect is represented by the same field. When the local effect is negligible the Love-Kirchhoff solution is valid for a thick cylinder. A shear effect shell theory may give for a thin cylinder a large error compared to the exact 3D solution on a thermal shock. The Love-Kirchhoff solution is generally not valid in the vicinity of a clamped or simply supported edge. A finite element program of thin shell with shear effect or thick shell ist not really reliable. A combination of 3D local solution and Love-Kirchhoff global solution through a transition zone may replace a complete 3D solution for not very thick structures. (orig./GL)

Effect of cavitation on flow structure of a tip vortex

Science.gov (United States)

Matthieu, Dreyer; Reclari, Martino; Farhat, Mohamed

2013-11-01

Tip vortices, which may develop in axial turbines and marine propellers, are often associated with the occurrence of cavitation because of the low pressure in their core. Although this issue has received a great deal of attention, it is still unclear how the phase transition affects the flow structure of such a vortex. In the present work, we investigate the change of the vortex structure due to cavitation incipience. The measurement of the velocity field is performed in the case of a tip vortex generated by an elliptical hydrofoil placed in the test section of EPFL high speed cavitation tunnel. To this end, a 3D stereo PIV is used with fluorescent seeding particles. A cost effective method is developed to produce in-house fluorescent seeding material, based on polyamide particles and Rhodamine-B dye. The amount of cavitation in the vortex core is controlled by the inlet pressure in the test section, starting with the non-cavitating case. We present an extensive analysis of the vorticity distribution, the vortex intensity and core size for various cavitation developments. This research is supported by CCEM and swisselectric research.

Structured population dynamics: continuous size and discontinuous stage structures.

Science.gov (United States)

Buffoni, Giuseppe; Pasquali, Sara

2007-04-01

A nonlinear stochastic model for the dynamics of a population with either a continuous size structure or a discontinuous stage structure is formulated in the Eulerian formalism. It takes into account dispersion effects due to stochastic variability of the development process of the individuals. The discrete equations of the numerical approximation are derived, and an analysis of the existence and stability of the equilibrium states is performed. An application to a copepod population is illustrated; numerical results of Eulerian and Lagrangian models are compared.

Quantum confinement effect in cheese like silicon nano structure fabricated by metal induced etching

Energy Technology Data Exchange (ETDEWEB)

Saxena, Shailendra K., E-mail: phd1211512@iiti.ac.in; Sahu, Gayatri; Sagdeo, Pankaj R.; Kumar, Rajesh [Material Research Laboratory, Discipline of Physics & MSEG, Indian Institute of Technology Indore, Madhya Pradesh-452017 (India)

2015-08-28

Quantum confinement effect has been studied in cheese like silicon nano-structures (Ch-SiNS) fabricated by metal induced chemical etching using different etching times. Scanning electron microscopy is used for the morphological study of these Ch-SiNS. A visible photoluminescence (PL) emission is observed from the samples under UV excitation at room temperature due to quantum confinement effect. The average size of Silicon Nanostructures (SiNS) present in the samples has been estimated by bond polarizability model using Raman Spectroscopy from the red-shift observed from SiNSs as compared to its bulk counterpart. The sizes of SiNS present in the samples decreases as etching time increase from 45 to 75 mintunes.

An impedance function approach for soil-structure interaction analyses including structure-to-structure interaction effects

International Nuclear Information System (INIS)

Gantayat, A.; Kamil, H.

1981-01-01

The dynamic soil-structure and structure-to-structure interaction effects may be determined in one of the two ways: by modeling the entire soil-structure system by a finite-element model, or by using a frequency-dependent (or frequency-independent) impedance function approach. In seismic design of nuclear power plant structures, the normal practice is to use the first approach because of its simplicity and easy availability of computer codes to perform such analyses. However, in the finite-element approach, because of the size and cost restrictions, the three-dimensional behavior of the entire soil-structure system and the radiation damping in soil are only approximately included by using a two-dimensional finite-element mesh. In using the impedance function approach, the soil-structure analyses can be performed in four steps: (a) determination of the dynamic properties of the fixed base superstructure, (b) determination of foundation and structure impedance matrices and input motions, (c) evaluation of foundation motion, (d) analysis of the fixed base superstructure using computed foundation motion. (orig./RW)

Effectiveness of a multifactorial handwashing program to reduce school absenteeism due to acute gastroenteritis.

Science.gov (United States)

Azor-Martínez, Ernestina; Cobos-Carrascosa, Elena; Gimenez-Sanchez, Francisco; Martínez-López, Jose Miguel; Garrido-Fernández, Pablo; Santisteban-Martínez, Joaquin; Seijas-Vazquez, Maria Luisa; Campos-Fernandez, Maria Amparo; Bonillo-Perales, Antonio

2014-02-01

Acute gastroenteritis (AGE) is one of the most common diseases among children and an important cause of school absenteeism. The aim of this study was to assess the effectiveness of a handwashing program using hand sanitizers for the prevention of school absenteeism due to AGE. A randomized, controlled and open study of a sample of 1341 children between 4 and 12 years of age, attending 5 state schools in Almería (Spain), with an 8-month follow up (academic year). The experimental group (EG) washed their hands with soap and water, complementing this with the use of a hand sanitizer, and the control group (CG) followed the usual handwashing procedure. Absenteeism rates due GI were compared between the 2 groups through the multivariate Poisson regression analysis. Percent days absent in both groups were compared with a Z-test. 446 cases of school absenteeism due to AGE were registered. The school children from the EG had a 36% lower risk of absenteeism due to AGE (IRR: 0.64, 95% confidence interval: 0.52-0.78) and a decrease in absenteeism of 0.13 episodes/child/academic year (0.27 of EG vs 0.40 CG/episodes/child/academic year, P absenteeism cases due to AGE.

Effect of bismuth ion substitution on structural properties of zinc ferrite nanoparticles

Directory of Open Access Journals (Sweden)

Naraavula Suresh Kumar

2016-06-01

Full Text Available Bismuth doped nano zinc ferrite particles having the general formula ZnFe2-xBixO4 (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25 were synthesized by sol-gel combustion method. The effect of bismuth doping on structural properties were investigated. The X-ray diffraction (XRD spectra confirm the single phase cubic spinel structure. The average crystallite sizes of all the samples were determined by Debye-Scherrer equation and are in the range 16–20 nm. The lattice parameter increases with the increase of bismuth ion concentration. This is due to the larger ionic radius of Bi3+ ions substituting smaller Fe3+ ions at octahedral sites (B-sites. The surface morphology of all compounds was studied by scanning electron microscope (SEM. The microstructure analysis and the particle size were examined by transmission electron microscope (TEM. The compositional stoichiometry of these samples was verified by energy dispersive spectroscopy (EDS analysis.

The effect of Berberine preparation on diarrheal symptoms due to Linac irradiation

International Nuclear Information System (INIS)

Hiasa, Tsuyoshi; Mitao, Satoshi; Tanaka, Motofumi; Matsubayashi, Shigeru; Kato, Koji

1979-01-01

Kyoberine, a preparation made from berberine, was administered in 20 cases of malignant tumors (16 cases of cervical carcinoma, 2 cases of corpus uteri carcinoma, and 2 cases of ovarian carcinoma) in which diarrhea was an acute symptom resulting from Linac irradiation. Diarrhea occurred frequently in the patients who received 1600 - 2000 rad. In regard to the characteristics of the feces, this drug was remarkably effective in 25% of the patients and effective in 65% total effectiveness, 90%. In regard to the frequency of diarrhea, it was remarkably effective in 30% of the patients and effective in 60% total effectiveness, 90%. A comprehensive assessment of the effect on the characteristics of the feces and the frequency of diarrhea revealed the drug to be remarkably effective in 7 cases (35%) and effective in 11 (55%). After serial administration of the drug, recurrence of diarrhea was noted only in one case out of 18 in which the drug was effective. Examinations of body weight, peripheral blood, the liver, the kidneys, and electrolytes revealed no side effects. This drug had an excellent effect on diarrhea due to Linac irradiation. Because of its depressant action on peristaltic reflexes and its anti-inflammatory and anti-ulcerative actions, it is hoped that it can be used to prevent radiation injuries. (Ueda, J.)

Effects of electron beam irradiation on the structural properties of polylactic acid/polyethylene blends

Energy Technology Data Exchange (ETDEWEB)

Bee, Soo-Tueen, E-mail: direct.beest@gmail.com [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Ratnam, C.T. [Radiation Processing Technology Division, Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Sin, Lee Tin, E-mail: direct.tinsin@gmail.com [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Tee, Tiam-Ting; Wong, Wai-Kien; Lee, Jiuun-Xiang [Department of Chemical Engineering, Faculty of Engineering and Science, Universiti Tunku Abdul Rahman, Jalan Genting Kelang, 53300 Setapak, Kuala Lumpur (Malaysia); Rahmat, A.R. [Department of Polymer Engineering, Faculty of Chemical Engineering, Universiti Teknologi Malaysia, 81310 UTM Skudai, Johor (Malaysia)

2014-09-01

Highlights: •Electron beam irradiation on polyethylene (LDPE) and polylactic acid (PLA) blends. •Irradiated PLA/LDPE blends exhibit structural rearrangement to highly ordered structure. •Irradiated PLA/LDPE matrix extends continuity of polymer matrix with larger fibrils diameter. -- Abstract: The purpose of this research was to investigate the effects of electron beam irradiation on the properties of polylactic acid (PLA) and low density polyethylene (LDPE) blends. The PLA were compounded with 20–80% LDPE and were exposed to electron beam irradiation dosages of 20–120 kGy. The results from gel content and X-ray diffraction analyses showed that the addition of LDPE to PLA effectively increased the gel content and crystallinity. However, an increasing percentage of LDPE reduced the tensile strength and Young’s modulus of the PLA/LDPE samples due to the lower intermolecular bonding of LDPE than of PLA. Moreover, an increase in irradiation dosages gradually decreased the mechanical properties of low-LDPE PLA/LDPE. In contrast, the increasing irradiation dosage enhanced the mechanical properties of higher-LDPE PLA/LDPE. These results indicate that higher amounts of LDPE effectively react with the release of free radicals within the amorphous phase if the blends are subjected to irradiation. The higher amounts of free radicals induce the formation of three-dimensional cross-linked networks in the polymer matrix and thus increase the gel content. The irradiation-induced cross-linking in PLA/LDPE samples improves the mechanical properties and crystallinity by promoting a structural rearrangement of the polymer matrix into a highly ordered structure.

Effects of electron beam irradiation on the structural properties of polylactic acid/polyethylene blends

International Nuclear Information System (INIS)

Bee, Soo-Tueen; Ratnam, C.T.; Sin, Lee Tin; Tee, Tiam-Ting; Wong, Wai-Kien; Lee, Jiuun-Xiang; Rahmat, A.R.

2014-01-01

Highlights: •Electron beam irradiation on polyethylene (LDPE) and polylactic acid (PLA) blends. •Irradiated PLA/LDPE blends exhibit structural rearrangement to highly ordered structure. •Irradiated PLA/LDPE matrix extends continuity of polymer matrix with larger fibrils diameter. -- Abstract: The purpose of this research was to investigate the effects of electron beam irradiation on the properties of polylactic acid (PLA) and low density polyethylene (LDPE) blends. The PLA were compounded with 20–80% LDPE and were exposed to electron beam irradiation dosages of 20–120 kGy. The results from gel content and X-ray diffraction analyses showed that the addition of LDPE to PLA effectively increased the gel content and crystallinity. However, an increasing percentage of LDPE reduced the tensile strength and Young’s modulus of the PLA/LDPE samples due to the lower intermolecular bonding of LDPE than of PLA. Moreover, an increase in irradiation dosages gradually decreased the mechanical properties of low-LDPE PLA/LDPE. In contrast, the increasing irradiation dosage enhanced the mechanical properties of higher-LDPE PLA/LDPE. These results indicate that higher amounts of LDPE effectively react with the release of free radicals within the amorphous phase if the blends are subjected to irradiation. The higher amounts of free radicals induce the formation of three-dimensional cross-linked networks in the polymer matrix and thus increase the gel content. The irradiation-induced cross-linking in PLA/LDPE samples improves the mechanical properties and crystallinity by promoting a structural rearrangement of the polymer matrix into a highly ordered structure

SOME EFFECTIVE METHODS OF TRAINING COMMUNICATIONS AND IT SPECIALISTS FROM MILITARY STRUCTURES

Directory of Open Access Journals (Sweden)

Gheorghe BOARU

2016-12-01

Full Text Available Service training military specialists in communications and informatics is part of the general system of training and education of the Romanian Armed Forces. Due to the place and the increasingly important role of the communications and information in the command and control of tactical, operational and strategic military structures, decision makers pay special attention to training this category of specialists, so that the technical support provided by them might meet all technical requirements and operational management of any military operation. There is a permanent concern to ensure the training principle of compatibility with modern armies of NATO, by choosing similar forms and methods of effective training, ensuring operational training. In this article we analyzed and proposed the most affordable and effective ways of training in communication and information, with suggestions for institutionalized training.

Organizational structures of companies versus project management effectiveness

Directory of Open Access Journals (Sweden)

Joanna Haffer

2012-12-01

Full Text Available An organizational structure, indicated as one out of the four main organizational conditions supporting project management, has an essential meaning for project execution. This article, based on the research results, describes different organizational structures of project-orientated enterprises, enumerating their advantages and disadvantages, and reveals the influence of inter-organizational relations on project management effectiveness in enterprises operating in Poland. The results indicate that the more a character of inter-organizational relations is heading towards project structure, the higher project management effectiveness is. In the next sequence the project management processes are supported by strong matrix structures, whereas the worst outcomes are provided by functional structures. Simultaneously, it was concluded that project structures are conducive to high advancement of project management processes, and among them, especially project risk management processes as well as communication, time and cost management processes.

Effective mass and damping of submerged structures

International Nuclear Information System (INIS)

Dong, R.G.

1979-01-01

A number of structures important for safety in nuclear power plants are submerged in water. These include spent fuel storage racks, main pressure relief valve lines, and internal structures in the reactor vessel. Dynamic analyses of such structures must include the force and damping effects of water. A wide variety of modeling assumptions are being used in design analyses, and currently there are no uniform positions by which to judge the adequacy of the assumptions . A study was caried out to establish a technical basis for evaluating the assymptions and to recommend suitable methods to describe the effects of the water. The results of the study were based on information published in the literature or conveyed by industrial firms. A survey of 32 firms and 49 technical references was carried out. Heavy emphasis was placed on validating the results with available experimental data. The information collected apply generally to idealized structures such as single isolated members, arrays of members and coaxial cylinders. The results of the study are categorized with respect to such idealized structures, and the applicability to actual reactor structures was discussed through observations and recommendations. (orig.)

The effects of soil-structure interaction modeling techniques on in-structure response spectra

International Nuclear Information System (INIS)

Johnson, J.J.; Wesley, D.A.; Almajan, I.T.

1977-01-01

The structure considered for this investigation consisted of the reactor containment building (RCB) and prestressed concrete reactor vessel (PCRV) for a HTGR plant. A conventional lumped-mass dynamic model in three dimensions was used in the study. The horizontal and vertical response, which are uncoupled due to the symmetry of the structure, were determined for horizontal and vertical excitation. Five different site conditions ranging from competent rock to a soft soil site were considered. The simplified approach to the overall plant analysis utilized stiffness proportional composite damping with a limited amount of soil damping consistent with US NRC regulatory guidelines. Selected cases were also analyzed assuming a soil damping value approximating the theoretical value. The results from the simplified approach were compared to those determined by rigorously coupling the structure to a frequency independent half-space representation of the soil. Finally, equivalent modal damping ratios were found by matching the frequency response at a point within the coupled soil-structure system determined by solution of the coupled and uncoupled equations of motion. The basis for comparison of the aforementioned techniques was the response spectra at selected locations within the soil-structure system. Each of the five site conditions was analyzed and in-structure response spectra were generated. The response spectra were combined to form a design envelope which encompasses the entire range of site parameters. Both the design envelopes and the site-by-site results were compared

Vapor pressure lowering effects due to salinity and suction pressure in the depletion of vapor-dominated geothermal reservoirs

Energy Technology Data Exchange (ETDEWEB)

Battistelli, A. [Aquater S.p.A., Pisa (Italy); Calore, C. [Istituto Internazionale per le Ricerche Geotermiche-CNR, Pisa (Italy); Pruess, K. [Lawrence Berkeley Lab., Berkeley, CA (United States)

1995-03-01

The equation-of-state module able to handle saline brines with non-condensible gas, developed for the TOUGH2 simulator, has been improved to include vapor pressure lowering (VPL) due to suction pressure as represented by Kelvin`s equation. In this equation the effects of salt are considered whereas those of non-condensible gas have currently been neglected. Numerical simulations of fluid production from tight matrix blocks have been performed to evaluate the impact of VPL effects due to salinity and suction pressure on the depletion behaviour of vapor-dominated geothermal reservoirs. Previous studies performed neglected VPL due to suction pressure showed that for initial NaCl mass fractions above threshold values, {open_quotes}sealing{close_quotes} of the block occurs and large amounts of liquid fluid may not be recovered. On the other hand, below the threshold value the matrix block dries out due to fluid production. The inclusion of VPL due to suction pressure does not allow complete vaporization of the liquid phase. As a result, the threshold NaCl concentration above which sealing of the matrix block occurs is increased. Above the {open_quotes}critical{close_quotes} NaCl concentration, block depletion behaviour with and without the VPL due to suction pressure is almost identical, as liquid phase saturation remains high even after long production times. As the VPL due to suction pressure depends mainly on capillary pressure, the shape of capillary pressure functions used in numerical simulations is important in determining VPL effects on block depletion.

Coma Morphology Due to an Extended Active Region and Implications for the Spin State of Comet Hale-Bopp

Science.gov (United States)

Samarasinha, Nalin H.

2000-01-01

We show that the circular character of continuum structures observed in the coma of comet Hale-Bopp around the perihelion passage is most likely due to a dust jet from a large extended active region on the surface. Coma morphology due to a wide jet is different from that due to a narrow jet. The latter shows foreshortening effects due to observing geometry, wider jet produces more circular features. This circularization effect provides a self-consistent explanation for the evolution of near-perihelion coma morphology. No changes in the direction of the rotational angular momentum vector are required during this period in contrast to the models of Schleicher et al. This circularization effect also enables us to produce near-circular coma features in the S-E quadrant during 1997 late February and therefore questions the basic premise on which Sekanina bases his morphological arguments for a gravitationally bound satellite nucleus.

Effect of geometry structure on critical properties

Science.gov (United States)

Jiang, Qing; Jiang, Xue-fan

1997-02-01

The effective-field renormalization group (EFRG) scheme is utilized to compute critical properties of the transverse Ising model (TIM) in a quantum-spin system. We distinguish differences between lattices of the same coordination number but of different structures and take effects of the first fluctuation correction into account. The improved results for the critical transverse field are obtained for several lattice structures even by considering the smallest possible cluster, which is in good agreement with series results.

Laser-induced fluorescences due to quadrupole moment transition and Stark effect in a He glow discharge

International Nuclear Information System (INIS)

Sakai, Hisashi; Takiyama, Ken; Kimura, Masahiko; Yamasaki, Motokuni; Fujita, Toshiaki; Oda, Toshiatsu; Kawasaki, Ken.

1993-01-01

The electric quadrupole moment transition and the Stark effect are investigated in a He hollow cathode discharge with laser-induced fluorescence method. It is shown that the forbidden transition from 2 1 S to 3 1 D in the negative glow is dominantly due to the quadrupole moment transition. This absorption coefficient is obtained from the laser-induced fluorescence intensity measurement in which the collisional transfers are taken into account. The result agrees with the theoretical coefficient. In the cathode dark space the fluorescence due to the Stark effect is also observed. Spatial distribution of the fluorescence is discussed, compared with the electric field distribution in the dark space. (author)

Critical Study of Corrosion Damaged Concrete Structures

OpenAIRE

Sallehuddin Shah Ayop; John Cairns

2013-01-01

Corrosion of steel reinforcement in concrete is one of the major problems with respect to the durability of reinforced concrete structures. The degradation of the structure strength due to reinforcement corrosion decreases its design life. This paper presents the literature study on the influence of the corrosion on concrete structure starting from the mechanism of the corrosion until the deterioration stage and the structural effects of corrosion on concrete structures.

Enhancement of transport properties of a Brownian particle due to quantum effects: Smoluchowski limit

International Nuclear Information System (INIS)

Shit, Anindita; Chattopadhyay, Sudip; Chaudhuri, Jyotipratim Ray

2012-01-01

Graphical abstract: By invoking physically motivated coordinate transformation into quantum Smoluchowski equation, we have presented a transparent treatment for the determination of the effective diffusion coefficient and current of a quantum Brownian particle. Substantial enhancement in the efficiency of the diffusive transport is envisaged due to the quantum correction effects. Highlights:: ► Transport of a quantum Brownian particle in a periodic potential has been addressed. ► Governing quantum Smoluchowski equation (QSE) includes state dependent diffusion. ► A coordinate transformation is used to recast QSE with constant diffusion. ► Transport properties increases in comparison to the corresponding classical result. ► This enhancement is purely a quantum effect. - Abstract: The transport property of a quantum Brownian particle that interacts strongly with a bath (in which a typical damping constant by far exceeds a characteristic frequency of the isolated system) under the influence of a tilted periodic potential has been studied by solving quantum Smoluchowski equation (QSE). By invoking physically motivated coordinate transformation into QSE, we have presented a transparent treatment for the determination of the effective diffusion coefficient of a quantum Brownian particle and the current (the average stationary velocity). Substantial enhancement in the efficiency of the diffusive transport is envisaged due to the quantum correction effects only if the bath temperature hovers around an appropriate range of intermediate values. Our findings also confirm the results obtained in the classical cases.

Effects of marine reserves versus nursery habitat availability on structure of reef fish communities.

Science.gov (United States)

Nagelkerken, Ivan; Grol, Monique G G; Mumby, Peter J

2012-01-01

No-take marine fishery reserves sustain commercial stocks by acting as buffers against overexploitation and enhancing fishery catches in adjacent areas through spillover. Likewise, nursery habitats such as mangroves enhance populations of some species in adjacent habitats. However, there is lack of understanding of the magnitude of stock enhancement and the effects on community structure when both protection from fishing and access to nurseries concurrently act as drivers of fish population dynamics. In this study we test the separate as well as interactive effects of marine reserves and nursery habitat proximity on structure and abundance of coral reef fish communities. Reserves had no effect on fish community composition, while proximity to nursery habitat only had a significant effect on community structure of species that use mangroves or seagrass beds as nurseries. In terms of reef fish biomass, proximity to nursery habitat by far outweighed (biomass 249% higher than that in areas with no nursery access) the effects of protection from fishing in reserves (biomass 21% lower than non-reserve areas) for small nursery fish (≤ 25 cm total length). For large-bodied individuals of nursery species (>25 cm total length), an additive effect was present for these two factors, although fish benefited more from fishing protection (203% higher biomass) than from proximity to nurseries (139% higher). The magnitude of elevated biomass for small fish on coral reefs due to proximity to nurseries was such that nursery habitats seem able to overrule the usually positive effects on fish biomass by reef reserves. As a result, conservation of nursery habitats gains importance and more consideration should be given to the ecological processes that occur along nursery-reef boundaries that connect neighboring ecosystems.

Effects of marine reserves versus nursery habitat availability on structure of reef fish communities.

Directory of Open Access Journals (Sweden)

Ivan Nagelkerken

Full Text Available No-take marine fishery reserves sustain commercial stocks by acting as buffers against overexploitation and enhancing fishery catches in adjacent areas through spillover. Likewise, nursery habitats such as mangroves enhance populations of some species in adjacent habitats. However, there is lack of understanding of the magnitude of stock enhancement and the effects on community structure when both protection from fishing and access to nurseries concurrently act as drivers of fish population dynamics. In this study we test the separate as well as interactive effects of marine reserves and nursery habitat proximity on structure and abundance of coral reef fish communities. Reserves had no effect on fish community composition, while proximity to nursery habitat only had a significant effect on community structure of species that use mangroves or seagrass beds as nurseries. In terms of reef fish biomass, proximity to nursery habitat by far outweighed (biomass 249% higher than that in areas with no nursery access the effects of protection from fishing in reserves (biomass 21% lower than non-reserve areas for small nursery fish (≤ 25 cm total length. For large-bodied individuals of nursery species (>25 cm total length, an additive effect was present for these two factors, although fish benefited more from fishing protection (203% higher biomass than from proximity to nurseries (139% higher. The magnitude of elevated biomass for small fish on coral reefs due to proximity to nurseries was such that nursery habitats seem able to overrule the usually positive effects on fish biomass by reef reserves. As a result, conservation of nursery habitats gains importance and more consideration should be given to the ecological processes that occur along nursery-reef boundaries that connect neighboring ecosystems.

Structural Model for the Effects of Perceived Indoor Work Environment on Sick Building Syndrome and Stress

Directory of Open Access Journals (Sweden)

Abdullah Nor Hazana

2016-01-01

Full Text Available Sick Building syndrome (SBS and stress have a prevalent influence on organizational productivity and competitiveness. Unhealthy employees not only tend to have high medical leaves but also low productivity due to ailments and discomforts. Studies that investigate the effects of indoor work environment on Sick Building Syndrome (SBS have yielded mixed results while their effect on stress has not been empirically established. Furthermore, studies that simultaneously investigate both SBS and stress are almost non-existent. Thus, this study aimed to study the effects of perceived indoor work environment on SBS and stress and the link between SBS and stress. A cross-sectional survey participated by 598 employees from various industries was conducted from September to October 2015. Data were analyzed using Partial Least Square Structural Equation Modeling (PLS-SEM to assess both the measurement model and the path structure. The results suggest that indoor work environment has significant yet the weak effect on SBS while it has no effect on stress. However, SBS has a strong significant relationship with stress. The implication of this study on the importance of conducive indoor work environment is discussed with suggestions for future studies.

Nonmonotonous electron mobility due to structurally induced resonant coupling of subband states in an asymmetric double quantum well

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R. K. Nayak

2015-11-01

Full Text Available We show that sharp nonmonotic variation of low temperature electron mobility μ can be achieved in GaAs/AlxGa1-xAs barrier delta-doped double quantum well structure due to quantum mechanical transfer of subband electron wave functions within the wells. We vary the potential profile of the coupled structure as a function of the doping concentration in order to bring the subbands into resonance such that the subband energy levels anticross and the eigen states of the coupled structure equally share both the wells thereby giving rise to a dip in mobility. When the wells are of equal widths, the dip in mobility occurs under symmetric doping of the side barriers. In case of unequal well widths, the resonance can be obtained by suitable asymmetric variation of the doping concentrations. The dip in mobility becomes sharp and also the wavy nature of mobility takes a rectangular shape by increasing the barrier width. We show that the dip in mobility at resonance is governed by the interface roughness scattering through step like changes in the subband mobilities. It is also gratifying to show that the drop in mobility at the onset of occupation of second subband is substantially supressed through the quantum mechanical transfer of subband wave functions between the wells. Our results can be utilized for performance enhancement of coupled quantum well devices.

Structural energetics of noble metals

International Nuclear Information System (INIS)

Mujibur Rahman, S.M.

1982-06-01

Structural energetics of the noble metals, namely Cu, Ag, and Au are investigated by employing a single-parameter pseudopotential. The calculations show that the lowest energy for all of these metals corresponds to FCC - their observed crystal structure. The one-electron contribution to the free energy is found to dominate the structural prediction for these metals. The present investigation strongly emphasizes that the effects due to band hybridization and core-core exchange play a significant role on the structural stability of the noble metals. (author)

Advances in soil-structure interaction studies

International Nuclear Information System (INIS)

Maheshwari, B.K.

2011-01-01

It is utmost important that lifeline infrastructures (such as bridges, hospitals, power plants, dams etc.) are safe and functional during earthquakes as damage or collapse of these structures may have far reaching implications. A lifeline's failure may hamper relief and rescue operations required just after an earthquake and secondly its indirect economical losses may be very severe. Therefore, safety of these structures during earthquakes is vital. Further, damage to nuclear facilities during earthquake may lead to disaster. These structures should be designed adequately taking into account all the important issues. Soil-Structure Interaction (SSI) is one of the design issues, which is often overlooked and even in some cases ignored. The effects of dynamic SSI are well understood and practiced in the nuclear power industry (for large foundations of the nuclear containment structures) since sixties. However, in last decade, there are many advances in techniques of SSI and those need to be incorporated in practice. Failures of many structures occurred during the 1989 Loma Prieta and 1994 Northridge, California earthquakes and the 1995 Kobe, Japan earthquake due to SSI or a related issue. Many jetties had failed in Andaman and Nicobar islands due to Sumatra earthquake and ensuing tsunamis. It is because of this recent experience that the importance of SSI on dynamic response of structures during earthquakes has been fully realized. General belief that the SSI effects are always beneficial for the structure is not correct. Some cases have been presented where it is shown that SSI effects are detrimental for the stability of the structure. This paper addresses the effects of dynamic SSI on the response of the structures and explains its importance. Further advances in SSI studies have been discussed

The crystal structure of Haloferax volcanii proliferating cell nuclear antigen reveals unique surface charge characteristics due to halophilic adaptation

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Morroll Shaun

2009-08-01

Full Text Available Abstract Background The high intracellular salt concentration required to maintain a halophilic lifestyle poses challenges to haloarchaeal proteins that must stay soluble, stable and functional in this extreme environment. Proliferating cell nuclear antigen (PCNA is a fundamental protein involved in maintaining genome integrity, with roles in both DNA replication and repair. To investigate the halophilic adaptation of such a key protein we have crystallised and solved the structure of Haloferax volcanii PCNA (HvPCNA to a resolution of 2.0 Å. Results The overall architecture of HvPCNA is very similar to other known PCNAs, which are highly structurally conserved. Three commonly observed adaptations in halophilic proteins are higher surface acidity, bound ions and increased numbers of intermolecular ion pairs (in oligomeric proteins. HvPCNA possesses the former two adaptations but not the latter, despite functioning as a homotrimer. Strikingly, the positive surface charge considered key to PCNA's role as a sliding clamp is dramatically reduced in the halophilic protein. Instead, bound cations within the solvation shell of HvPCNA may permit sliding along negatively charged DNA by reducing electrostatic repulsion effects. Conclusion The extent to which individual proteins adapt to halophilic conditions varies, presumably due to their diverse characteristics and roles within the cell. The number of ion pairs observed in the HvPCNA monomer-monomer interface was unexpectedly low. This may reflect the fact that the trimer is intrinsically stable over a wide range of salt concentrations and therefore additional modifications for trimer maintenance in high salt conditions are not required. Halophilic proteins frequently bind anions and cations and in HvPCNA cation binding may compensate for the remarkable reduction in positive charge in the pore region, to facilitate functional interactions with DNA. In this way, HvPCNA may harness its environment as

The crystal structure of Haloferax volcanii proliferating cell nuclear antigen reveals unique surface charge characteristics due to halophilic adaptation

Science.gov (United States)

Winter, Jody A; Christofi, Panayiotis; Morroll, Shaun; Bunting, Karen A

2009-01-01

Background The high intracellular salt concentration required to maintain a halophilic lifestyle poses challenges to haloarchaeal proteins that must stay soluble, stable and functional in this extreme environment. Proliferating cell nuclear antigen (PCNA) is a fundamental protein involved in maintaining genome integrity, with roles in both DNA replication and repair. To investigate the halophilic adaptation of such a key protein we have crystallised and solved the structure of Haloferax volcanii PCNA (HvPCNA) to a resolution of 2.0 Å. Results The overall architecture of HvPCNA is very similar to other known PCNAs, which are highly structurally conserved. Three commonly observed adaptations in halophilic proteins are higher surface acidity, bound ions and increased numbers of intermolecular ion pairs (in oligomeric proteins). HvPCNA possesses the former two adaptations but not the latter, despite functioning as a homotrimer. Strikingly, the positive surface charge considered key to PCNA's role as a sliding clamp is dramatically reduced in the halophilic protein. Instead, bound cations within the solvation shell of HvPCNA may permit sliding along negatively charged DNA by reducing electrostatic repulsion effects. Conclusion The extent to which individual proteins adapt to halophilic conditions varies, presumably due to their diverse characteristics and roles within the cell. The number of ion pairs observed in the HvPCNA monomer-monomer interface was unexpectedly low. This may reflect the fact that the trimer is intrinsically stable over a wide range of salt concentrations and therefore additional modifications for trimer maintenance in high salt conditions are not required. Halophilic proteins frequently bind anions and cations and in HvPCNA cation binding may compensate for the remarkable reduction in positive charge in the pore region, to facilitate functional interactions with DNA. In this way, HvPCNA may harness its environment as opposed to simply surviving in

Does the edge effect influence plant community structure in a tropical dry forest?

Directory of Open Access Journals (Sweden)

Diogo Gallo Oliveira

2013-04-01

Full Text Available Edge effects are considered a key factor in regulating the structure of plant communities in different ecosystems. However, regardless to few studies, edge influence does not seem to be decisive in semiarid regions such as the Brazilian tropical dry forest known as Caatinga but this issue remains inconclusive. The present study tests the null hypothesis that the plant community of shrubs and trees does not change in its structure due to edge effects. Twenty-four plots (20 x 20 m were set up in a fragment of Caatinga, in which 12 plots were in the forest edges and 12 plots were inside the fragment. Tree richness, abundance and species composition did not differ between edge and interior plots. The results of this study are in agreement with the pattern previously found for semiarid environments and contrasts with previous results obtained in different environments such as Rainforests, Savanna and Forest of Araucaria, which indicate abrupt differences between the border and interior of the plant communities in these ecosystems, and suggest that the community of woody plants of the Caatinga is not ecologically affected by the presence of edges.

A Review of the Effects of Elevated Temperature on Concrete Materials and Structures

International Nuclear Information System (INIS)

Naus, D.J.; Graves, H.L. III

2006-01-01

Concrete's properties are more complex than those of most materials because not only is concrete a composite material whose constituents have different properties, but its properties depend upon moisture and porosity. Exposure of concrete to elevated temperature affects its mechanical and physical properties. Elements could distort and displace, and, under certain conditions, the concrete surfaces could spall due to the buildup of steam pressure. Because thermally-induced dimensional changes, loss of structural integrity, and release of moisture and gases resulting from the migration of free water could adversely affect plant operations and safety, a complete understanding of the behavior of concrete under long-term elevated-temperature exposure as well as both during and after a thermal excursion resulting from a postulated design-basis accident condition is essential for reliable design evaluations and assessments of nuclear power plant structures. As the properties of concrete change with respect to time and the environment to which it is exposed, an assessment of the effects of concrete aging is also important in performing safety evaluations. The effects of elevated temperature on Portland cement concretes and constituent materials are summarized, design codes and standards identified, and considerations for elevated temperature service noted. (authors)

Structural response of steel high rise buildings to fire

DEFF Research Database (Denmark)

Gentili, Filippo; Giuliani, Luisa; Bontempi, Franco

2013-01-01

Due to the significant vertical elevation and complexity of the structural system, high rise buildings may suffer from the effects of fire more than other structures. For this reason, in addition to evacuation strategies and active fire protection, a careful consideration of structural response t...

Effects of shallow natural gas well structures and associated roads on grassland songbird reproductive success in Alberta, Canada.

Directory of Open Access Journals (Sweden)

Jenny Yoo

Full Text Available Grassland songbird populations across North America have experienced dramatic population declines due to habitat loss and degradation. In Canada, energy development continues to fragment and disturb prairie habitat, but effects of oil and gas development on reproductive success of songbirds in North American mixed-grass prairies remains largely unknown. From 2010-2012, in southeastern Alberta, Canada, we monitored 257 nests of two ground-nesting grassland songbird species, Savannah sparrow (Passerculus sandwichensis and chestnut-collared longspur (Calcarius ornatus. Nest locations varied with proximity to and density of conventional shallow gas well structures and associated roads in forty-two 258-ha mixed-grass prairie sites. We estimated the probabilities of nest success and clutch size relative to gas well structures and roads. There was little effect of distance to or density of gas well structure on nest success; however, Savannah sparrow experienced lower nest success near roads. Clutch sizes were lower near gas well structures and cattle water sources. Minimizing habitat disturbance surrounding gas well structures, and reducing abundance of roads and trails, would help minimize impacts on reproductive success for some grassland songbirds.

Adaptive memory: Is the animacy effect on memory due to emotional arousal?

Science.gov (United States)

Meinhardt, Martin J; Bell, Raoul; Buchner, Axel; Röer, Jan P

2018-05-07

Animate entities are often better remembered than inanimate ones. The proximal mechanisms underlying this animacy effect on recall are unclear. In two experiments, we tested whether the animacy effect is due to emotional arousal. Experiment 1 revealed that translations of the animate words used in the pioneering study of Nairne et al. (Psychological science, 24, 2099-2105, 2013) were perceived as being more arousing than translations of the inanimate words, suggesting that animacy might have been confounded with arousal in previous studies. In Experiment 2, new word lists were created in which the animate and inanimate words were matched on arousal (amongst several other dimensions), and participants were required to reproduce the animate and inanimate words in a free recall task. There was a tendency towards better memory for arousing items, but robust animacy effects were obtained even though animate and inanimate words were matched on arousal. Thus, while arousal may contribute to the animacy effect when it is not carefully controlled for, it cannot explain the memory advantage of animate items.

Effects of shearing on biogas production and microbial community structure during anaerobic digestion with recuperative thickening.

Science.gov (United States)

Yang, Shufan; Phan, Hop V; Bustamante, Heriberto; Guo, Wenshan; Ngo, Hao H; Nghiem, Long D

2017-06-01

Recuperative thickening can intensify anaerobic digestion to produce more biogas and potentially reduce biosolids odour. This study elucidates the effects of sludge shearing during the thickening process on the microbial community structure and its effect on biogas production. Medium shearing resulted in approximately 15% increase in biogas production. By contrast, excessive or high shearing led to a marked decrease in biogas production, possibly due to sludge disintegration and cell lysis. Microbial analysis using 16S rRNA gene amplicon sequencing showed that medium shearing increased the evenness and diversity of the microbial community in the anaerobic digester, which is consistent with the observed improved biogas production. By contrast, microbial diversity decreased under either excessive shearing or high shearing condition. In good agreement with the observed decrease in biogas production, the abundance of Bacteroidales and Syntrophobaterales (which are responsible for hydrolysis and acetogenesis) decreased due to high shearing during recuperative thickening. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

Risk estimates of stochastic effects due to exposure to radiation - a stochastic harm index

International Nuclear Information System (INIS)

Gonen, Y.G.

1980-01-01

The effects of exposure to low level radiation on the survival probability and life expectancy were investigated. The 1977 vital statistics of Jewish males in Israel were used as a baseline, mainly the data on normalized survival probability and life expectation as functions of age. Assumed effects of exposure were superposed on these data and the net differences calculated. It was found that the realistic rate effects of exposure to radiation are generally less than calculated by multiplying the collective dose by the risk factor. The effects are strongly age-dependent, decreasing sharply with age at exposure. The assumed harm due to exposure can be more than offset by improvements in medical care and safety. (H.K.)

Fine-structure excitation of Fe II and Fe III due to collisions with electrons

Science.gov (United States)

Wan, Yier; Qi, Yueying; Favreau, Connor; Loch, Stuart; Stancil, P.; Ballance, Connor; McLaughlin, Brendan

2018-06-01

Atomic data of iron peak elements are of great importance in astronomical observations. Among all the ionization stages of iron, Fe II and Fe III are of particular importance because of the high cosmic abundance, relatively low ionization potential and complex open d-shell atomic structure. Fe II and Fe III emission are observed from nearly all classes of astronomical objects over a wide spectral range from the infrared to the ultraviolet. To meaningfully interpret these spectra, astronomers have to employ highly complex modeling codes with reliable collision data to simulate the astrophysical observations. The major aim of this work is to provide reliable atomic data for diagnostics. We present new collision strengths and effective collisions for electron impact excitation of Fe II and Fe III for the forbidden transitions among the fine-structure levels of the ground terms. A very fine energy mesh is used for the collision strengths and the effective collision strengths are calculated over a wide range of electron temperatures of astrophysical importance (10-2000 K). The configuration interaction state wave functions are generated with a scaled Thomas-Fermi-Dirac-Amaldi (TFDA) potential, while the R-matrix plus intermediate coupling frame transformation (ICFT), Breit-Pauli R-matrix and Dirac R-matrix packages are used to obtain collision strengths. Influences of the different methods and configuration expansions on the collisional data are discussed. Comparison is made with earlier theoretical work and differences are found to occur at the low temperatures considered here.This work was funded by NASA grant NNX15AE47G.

Enhanced biennial variability in the Pacific due to Atlantic capacitor effect.

Science.gov (United States)

Wang, Lei; Yu, Jin-Yi; Paek, Houk

2017-03-20

The El Niño-Southern Oscillation (ENSO) and the variability in the Pacific subtropical highs (PSHs) have major impacts on social and ecological systems. Here we present an Atlantic capacitor effect mechanism to suggest that the Atlantic is a key pacemaker of the biennial variability in the Pacific including that in ENSO and the PSHs during recent decades. The 'charging' (that is, ENSO imprinting the North Tropical Atlantic (NTA) sea surface temperature (SST) via an atmospheric bridge mechanism) and 'discharging' (that is, the NTA SST triggering the following ENSO via a subtropical teleconnection mechanism) processes alternate, generating the biennial rhythmic changes in the Pacific. Since the early 1990s, a warmer Atlantic due to the positive phase of Atlantic multidecadal oscillation and global warming trend has provided more favourable background state for the Atlantic capacitor effect, giving rise to enhanced biennial variability in the Pacific that may increase the occurrence frequency of severe natural hazard events.

Effects of magnetized walls on the particle structure and the yield stress of magnetorheological fluids

Energy Technology Data Exchange (ETDEWEB)

Zhou, Jianfeng, E-mail: zhoujianfeng@njtech.edu.cn [School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu (China); Mo, Jingwen [Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong); Shao, Chunlei [School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, Jiangsu (China); Li, Zhigang [Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon (Hong Kong)

2015-09-01

In this work, we investigate the quasi-static shear deformation of magnetic particles (MPs) in a Couette flow of magnetorheological (MR) fluids through Stokesian dynamic simulations. The magnetized walls are modeled by a congregation of magnetic dipoles and their effects on the MPs are considered. The simple shear flow of the base fluid with linear velocity distribution is used to generate the shear deformation of the MP structure and the yield stresses under different shear rates are obtained. Comparing with the relatively long chains forming in base fluid without the effect of magnetized walls, the initial structure of MPs is mainly in the form of short chains due to the attractive force of walls. At the beginning of the shear deformation of the MP structure, the concentration of MPs near the walls is found. As the shear deformation develops, however, the chains concentrate at the center of the simulation domain and the MPs near wall boundaries are attracted to the center. The yield stress depends on the initial structure of MPs which is affected by the magnetized walls. It is revealed that the larger shear rate of base fluid results in the larger yield stress, and the effects of the magnetization intensity of the walls and their space distance on the yield stress are also investigated. - Highlights: • We model a Couette flow of magnetorheological fluid considering magnetized walls. • The walls are modeled by a congregation of magnetic dipoles. • Initial structure of MPs is remarkably affected by the walls, so is yield stress. • Larger base fluid shear rate causes the larger shear deformation and larger yield stress.

Effects of magnetized walls on the particle structure and the yield stress of magnetorheological fluids

International Nuclear Information System (INIS)

Zhou, Jianfeng; Mo, Jingwen; Shao, Chunlei; Li, Zhigang

2015-01-01

In this work, we investigate the quasi-static shear deformation of magnetic particles (MPs) in a Couette flow of magnetorheological (MR) fluids through Stokesian dynamic simulations. The magnetized walls are modeled by a congregation of magnetic dipoles and their effects on the MPs are considered. The simple shear flow of the base fluid with linear velocity distribution is used to generate the shear deformation of the MP structure and the yield stresses under different shear rates are obtained. Comparing with the relatively long chains forming in base fluid without the effect of magnetized walls, the initial structure of MPs is mainly in the form of short chains due to the attractive force of walls. At the beginning of the shear deformation of the MP structure, the concentration of MPs near the walls is found. As the shear deformation develops, however, the chains concentrate at the center of the simulation domain and the MPs near wall boundaries are attracted to the center. The yield stress depends on the initial structure of MPs which is affected by the magnetized walls. It is revealed that the larger shear rate of base fluid results in the larger yield stress, and the effects of the magnetization intensity of the walls and their space distance on the yield stress are also investigated. - Highlights: • We model a Couette flow of magnetorheological fluid considering magnetized walls. • The walls are modeled by a congregation of magnetic dipoles. • Initial structure of MPs is remarkably affected by the walls, so is yield stress. • Larger base fluid shear rate causes the larger shear deformation and larger yield stress

Dianthraceno[a,e]pentalenes: Synthesis, crystallographic structures and applications in organic field-effect transistors

KAUST Repository

Dai, Gaole

2015-01-01

Two soluble and stable dianthraceno[a,e]pentalenes with two (DAP1) and six (DAP2) phenyl substituents were synthesized. Both compounds possess a small energy band gap and show amphoteric redox behaviour due to intramolecular donor-accepter interactions. X-ray crystallographic analysis revealed that DAP2 has a closely packed structure with multi-dimensional [C-H⋯π] interactions although there are no π-π interactions between the dianthraceno[a,e]pentalene cores. As a result, solution-processed field effect transistors based on DAP2 exhibited an average hole mobility of 0.65 cm2 V-1 s-1. Under similar conditions, DAP1 showed an average field effect hole mobility of 0.001 cm2 V-1 s-1. This journal is

Quasiparticle band gap of organic-inorganic hybrid perovskites: Crystal structure, spin-orbit coupling, and self-energy effects

Science.gov (United States)

Gao, Weiwei; Gao, Xiang; Abtew, Tesfaye A.; Sun, Yi-Yang; Zhang, Shengbai; Zhang, Peihong

2016-02-01

The quasiparticle band gap is one of the most important materials properties for photovoltaic applications. Often the band gap of a photovoltaic material is determined (and can be controlled) by various factors, complicating predictive materials optimization. An in-depth understanding of how these factors affect the size of the gap will provide valuable guidance for new materials discovery. Here we report a comprehensive investigation on the band gap formation mechanism in organic-inorganic hybrid perovskites by decoupling various contributing factors which ultimately determine their electronic structure and quasiparticle band gap. Major factors, namely, quasiparticle self-energy, spin-orbit coupling, and structural distortions due to the presence of organic molecules, and their influences on the quasiparticle band structure of organic-inorganic hybrid perovskites are illustrated. We find that although methylammonium cations do not contribute directly to the electronic states near band edges, they play an important role in defining the band gap by introducing structural distortions and controlling the overall lattice constants. The spin-orbit coupling effects drastically reduce the electron and hole effective masses in these systems, which is beneficial for high carrier mobilities and small exciton binding energies.

Structural Emergency Control Paradigm

DEFF Research Database (Denmark)

Vu, Thanh Long; Chatzivasileiadis, Spyros; Chiang, Hsiao-Dong

2017-01-01

demand and hopefully stabilize the system. This traditional emergency control results in interrupted service with severe economic damage to customers. Also, such control is usually less effective due to the lack of coordination among protective devices. In this paper, we propose a novel structural...

Effects of gastrointestinal tissue structure on computed dipole vectors

Directory of Open Access Journals (Sweden)

Pullan Andrew J

2007-10-01

Full Text Available Abstract Background Digestive diseases are difficult to assess without using invasive measurements. Non-invasive measurements of body surface electrical and magnetic activity resulting from underlying gastro-intestinal activity are not widely used, in large due to their difficulty in interpretation. Mathematical modelling of the underlying processes may help provide additional information. When modelling myoelectrical activity, it is common for the electrical field to be represented by equivalent dipole sources. The gastrointestinal system is comprised of alternating layers of smooth muscle (SM cells and Interstitial Cells of Cajal (ICC. In addition the small intestine has regions of high curvature as the intestine bends back upon itself. To eventually use modelling diagnostically, we must improve our understanding of the effect that intestinal structure has on dipole vector behaviour. Methods Normal intestine electrical behaviour was simulated on simple geometries using a monodomain formulation. The myoelectrical fields were then represented by their dipole vectors and an examination on the effect of structure was undertaken. The 3D intestine model was compared to a more computationally efficient 1D representation to determine the differences on the resultant dipole vectors. In addition, the conductivity values and the thickness of the different muscle layers were varied in the 3D model and the effects on the dipole vectors were investigated. Results The dipole vector orientations were largely affected by the curvature and by a transmural gradient in the electrical wavefront caused by the different properties of the SM and ICC layers. This gradient caused the dipoles to be oriented at an angle to the principal direction of electrical propagation. This angle increased when the ratio of the longitudinal and circular muscle was increased or when the the conductivity along and across the layers was increased. The 1D model was able to represent the

Irradiation of: MOS field effect structures effect of the radiation dose

International Nuclear Information System (INIS)

Leray, J.L.

1989-01-01

The radiation effects on the structure and the operation of a metal-oxide semiconductor (MOS) are studied. The phenomenology of the radiation damage is analyzed as a function of the accumulated radiation dose and the time. The chronology of the phenomena which takes place in the oxide and the radiation transient phases in MOS structures are discussed. The equivalence of different radiations on SiO2 and other semiconductors is analyzed. The models applied to the study of the radiation permanent effects are reviewed [fr

Effective Method for Determining Environmental Loads on Supporting Structures for Offshore Wind Turbines

Directory of Open Access Journals (Sweden)

Dymarski Paweł

2016-01-01

Full Text Available This paper presents a description of an effective method for determining loads due to waves and current acting on the supporting structures of the offshore wind turbines. This method is dedicated to the structures consisting of the cylindrical or conical elements as well as (truncates pyramids of polygon with a large number of sides (8 or more. The presented computational method is based on the Morison equation, which was originally developed only for cylindrically shaped structures. The new algorithm shown here uses the coefficients of inertia and drag forces that were calculated for non-cylindrical shapes. The analysed structure consists of segments which are truncated pyramids on the basis of a hex decagon. The inertia coefficients, CM, and drag coefficients, CD, were determined using RANSE-CFD calculations. The CFD simulations were performed for a specific range of variation of the period, and for a certain range of amplitudes of the velocity. In addition, the analysis of influence of the surface roughness on the inertia and drag coefficients was performed. In the next step, the computations of sea wave, current and wind load on supporting structure for the fifty-year storm were carried out. The simulations were performed in the time domain and as a result the function of forces distribution along the construction elements was obtained. The most unfavourable distribution of forces will be used, to analyse the strength of the structure, as the design load.

Semidiurnal signal in UT1 due to the influence of tidal gravitation on the triaxial structure of the Earth

Science.gov (United States)

Brzeziński, Aleksander; Capitaine, Nicole

2010-11-01

The axial component of Earth rotation, which is conventionally expressed by Universal Time (UT1), contains small physical signals with diurnal and subdiurnal periods. This part of the spectrum is dominated by the tidal effects which are regular and predictable. The largest components express the influence of the gravitationally forced ocean tides with diurnal and semidiurnal periods and amplitudes up to 0.02 milliseconds (ms) in UT1 corresponding to an angular displacement of 0.30 milliarcseconds (mas); see Table 8.3 of the IERS Conventions (IERS, 2003). There are also smaller subdiurnal components (amplitudes up to 0.03 mas), designated as “spin libration” by Chao et al. (1991), due to direct influence of the tidal gravitation on those features of the Earth's density distribution which are expressed by the non-zonal terms of the geopotential. These components are not included in the models recommended by the IERS Conventions, in contrast to the corresponding effect in polar motion (ibid., Table 5.1). Here we consider in detail the subdiurnal libration in UT1. We derive an analytical solution for the structural model of the Earth consisting of an elastic mantle and a liquid core which are not coupled to each other. The reference solution for the rigid Earth is computed by using the satellite-determined coefficients of geopotential and the recent developments of the tide generating potential (TGP). We arrived to the conclusion that the set of terms with amplitudes exceeding the truncation level of 0.005 mas consists of 11 semidiurnal harmonics due to the influence of the TGP term u22 on the equatorial flattening of the Earth expressed by the Stokes coefficients C22, S22. There is an excellent agreement between our estimates for the rigid Earth and the amplitudes derived by Wünsch (1991). The only important difference is the term with the tidal code ν2, which seems to be overlooked in the development of Wünsch. Our amplitudes computed for an elastic Earth with

Soil-Structure Interaction Effect on Fragility Curve of 3D Models of Concrete Moment-Resisting Buildings

Directory of Open Access Journals (Sweden)

Ali Anvarsamarin

2018-01-01

Full Text Available This paper presents the probabilistic generation of collapse fragility curves for evaluating the performance of 3D, reinforced concrete (RC moment-resisting building models, considering soil-structure interaction (SSI by concentration on seismic uncertainties. It considers collapse as the loss of lateral load-resisting capacity of the building structures due to severe ground shaking and consequent large interstory drifts intensified by P-Δ effects as well as the strength and stiffness deterioration of their lateral load carrying systems. The estimation of the collapse performance of structures requires the relation between the intensity measure (IM and the probability of collapse that is determined using the generated collapse fragility curves. Considering a number of 6-, 12-, and 18-story, 3D, RC moment-resisting buildings, two scalar IMs are employed to estimate their collapse fragility curve. On the other hand, the effect of the site soil type on the collapse fragility curves was taken into account by considering the soil-structure interaction. According to the obtained results, adopting the average of spectral acceleration (Saavg intensity measure is more efficient in capturing the effect of the inherent uncertainties of the strong ground motions on the structural response parameters. In addition, considering the SSI for soil type D with shear-wave velocity of 180 m/s to 360 m/s reduces the median of intensity measure (IM = Sa(T1 of fragility curve in 6-, 12-, and 18-story buildings by 4.92%, 22.26%, and 23.03%, respectively.

Dynamic Analysis of Partially Embedded Structures Considering Soil-Structure Interaction in Time Domain

Directory of Open Access Journals (Sweden)

Sanaz Mahmoudpour

2011-01-01

Full Text Available Analysis and design of structures subjected to arbitrary dynamic loadings especially earthquakes have been studied during past decades. In practice, the effects of soil-structure interaction on the dynamic response of structures are usually neglected. In this study, the effect of soil-structure interaction on the dynamic response of structures has been examined. The substructure method using dynamic stiffness of soil is used to analyze soil-structure system. A coupled model based on finite element method and scaled boundary finite element method is applied. Finite element method is used to analyze the structure, and scaled boundary finite element method is applied in the analysis of unbounded soil region. Due to analytical solution in the radial direction, the radiation condition is satisfied exactly. The material behavior of soil and structure is assumed to be linear. The soil region is considered as a homogeneous half-space. The analysis is performed in time domain. A computer program is prepared to analyze the soil-structure system. Comparing the results with those in literature shows the exactness and competency of the proposed method.

Human due diligence.

Science.gov (United States)

Harding, David; Rouse, Ted

2007-04-01

Most companies do a thorough job of financial due diligence when they acquire other companies. But all too often, deal makers simply ignore or underestimate the significance of people issues in mergers and acquisitions. The consequences are severe. Most obviously, there's a high degree of talent loss after a deal's announcement. To make matters worse, differences in decision-making styles lead to infighting; integration stalls; and productivity declines. The good news is that human due diligence can help companies avoid these problems. Done early enough, it helps acquirers decide whether to embrace or kill a deal and determine the price they are willing to pay. It also lays the groundwork for smooth integration. When acquirers have done their homework, they can uncover capability gaps, points of friction, and differences in decision making. Even more important, they can make the critical "people" decisions-who stays, who goes, who runs the combined business, what to do with the rank and file-at the time the deal is announced or shortly thereafter. Making such decisions within the first 30 days is critical to the success of a deal. Hostile situations clearly make things more difficult, but companies can and must still do a certain amount of human due diligence to reduce the inevitable fallout from the acquisition process and smooth the integration. This article details the steps involved in conducting human due diligence. The approach is structured around answering five basic questions: Who is the cultural acquirer? What kind of organization do you want? Will the two cultures mesh? Who are the people you most want to retain? And how will rank-and-file employees react to the deal? Unless an acquiring company has answered these questions to its satisfaction, the acquisition it is making will be very likely to end badly.

Study on the Effect of Secondary Banded Structure on the Fatigue Property of Non-Quenched and Tempered Micro Alloyed Steel

Science.gov (United States)

Yajie, Cheng; Qingliang, Liao; Yue, Zhang

Due to composition segregation and cooling speed, streamline or banded structure were often obtained in the thermal forming parts along the direction of parts forming. Generally speaking, banded structure doesn't decrease the longitudinal mechanical properties, so the secondary banded structure can't get enough attention. The effect of secondary banded structure on the fatigue properties of micro alloyed DG20Mn and 35CrMo steel was investigated using the axial tensile fatigue test of stress ratio of 0.1. The result shows that secondary banded structure was obtained in the center of the steel parts, because of the composition segregation and the lower cooling rate in center part of steel. Secondary banded structure has no significant effect on axial tensile properties of both DG20Mn and 35CrMo, but decreases the axial tensile fatigue performance of DG20Mn steel. This study suggests that under the high cyclic tensile stress, multi-source damage cracks in steel initiated by large strain of pearlite of secondary banded structure, which is larger than damage strain, is the major factor of the decrease of fatigue life of steel.

Correction of autonomic nervous system indicators due to the effect of geomagnetic perturbations in patients with remote after effects of closed traumatic brain injury

Directory of Open Access Journals (Sweden)

V. A. Коrshnyak

2016-08-01

  Abstract The authors show that in modern biology, life is seen as the ability of living matter, and namely in medicine – the ability of human body, to maintain the existence in natural environment. From this perspective, it is extremely necessary to synchronize the activity of body structures among themselves taking into account the changes of environmental factors. Achieving the harmony between the body activity and environmental changes is carried out using an external pacemaker of life processes’ activity, the role of which is performed by the geomagnetic field (GMF.  This became possible due to the fact that the life processes are cyclical, i.e. they possess rhythmic characteristics, and GMF is an electromagnetic field which is changing its characteristics rhythmically.  The material for the present study were the data obtained during the neurological examination of 20 healthy people and 100 patients with remote consequences of CTBI which were treated in the clinic of autonomic nervous system pathology of the SI "Institute of neurology, psychiatry and narcology of the NAMS of Ukraine". The results investigations have showed that geomagnetic perturbations, which modify the GMF parameters, exacerbate the disorders of VNS in patients with remote after effects of CTBI. It is associated with the increased desynchronization of the activity of suprasegmental structures of VNS and with breach of brain vascular system’s status that occurs during a magnetic storm. The acupuncture that is aimed at restoring of synchronization of activity of suprasegmental structures of VNS significantly reduces its sensitivity to the geomagnetic disturbances. Keywords: magnetic storm, closed head injury, autonomic nervous system.

Photon structure functions with heavy particle mass effects

Energy Technology Data Exchange (ETDEWEB)

Uematsu, Tsuneo, E-mail: uematsu@scphys.kyoto-u.jp [Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto, 606-8502 (Japan); Maskawa Institute for Science and Culture, Kyoto Sangyo University, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan)

2013-01-15

In the framework of the perturbative QCD we investigate heavy particle mass effects on the unpolarized and polarized photon structure functions, F{sub 2}{sup γ} and g{sub 1}{sup γ}, respectively. We present our basic formalism to treat heavy particle mass effects to NLO in perturbative QCD. We also study heavy quark effects on the QCD sum rule for the first moment of g{sub 1}{sup γ}, which is related to axial anomaly. The photon structure function in supersymmetric QCD is also briefly discussed.

A study on the effects of seawater on the durable life of concrete structures(I)

Energy Technology Data Exchange (ETDEWEB)

Oh, Byung Hwan; Chang, Bong Seok; Chang, Seung Yeob; Cheon, Se Jin; Cheong, Sang Hwa; Yu, Yeong; Shin, Yong Seok; Shin, Myeong Su; Hyeong, Sang Su [Seoul Nationl Univ., Seoul (Korea, Republic of)

1998-06-15

Recently, large scale concrete structures such as Nuclear Power Plants and offshore structures are actively being built in this country. These structures are subject to heavy attack due to seawater environment. A reasonable consideration for corrosion has not been paid to the structures in the past decades due to insufficient research data and guidelines. The durability os emerging as one of the most important factors in the design and construction of concrete structures. The purpose of the present study is, therefore, to explore the corrosion mechanism and penetration mechanism of chloride ion, and to establish the evaluation procedure of durability life of concrete structures. A comprehensive experimental program has been set up and severe the types and amount of cement and mineral admixtures. The test results on the corrosion and strength characteristics of various concrete with be reported in the second-year report since the corrosion tests need long time. The results can be used in the design and construction of concrete structures in the future.

Effect of groundwater on soil-structure interaction

International Nuclear Information System (INIS)

Xu, J.; Bandyopadhyay, K.K.; Kassir, M.K.

1995-01-01

This paper presents results of a parametric study performed to investigate the effect of pore water in saturated soils on the response of nuclear containment structures to seismic motions. The technique employed uses frequency domain algorithm which incorporates impedances for both dry and saturated soils into an SSI model. A frequency domain time history analysis is carried out using the computer code CARES for a typical PWR containment structure. Structural responses presented in terms of floor response spectra indicate that considering the presence of the pore water in soils could benefit the design of massive nuclear containment structures

Magnetic activity at infrared frequencies in structured metallic photonic crystals

International Nuclear Information System (INIS)

O'Brien, S.; Pendry, J.P.

2002-01-01

We derive the effective permeability and permittivity of a nanostructured metallic photonic crystal by analysing the complex reflection and transmission coefficients for slabs of various thicknesses. These quantities were calculated using the transfer matrix method. Our results indicate that these structures could be used to realize a negative effective permeability, at least up to infrared frequencies. The origin of the negative permeability is a resonance due to the internal inductance and capacitance of the structure. We also present an analytic model for the effective permeability of the crystal. The model reveals the importance of the inertial inductance due to the finite mass of the electrons in the metal. We find that this contribution to the inductance has implications for the design of metallic magnetic structures in the optical region of the spectrum. We show that the magnetic activity in the structure is accompanied by the concentration of the incident field energy into very small volumes within the structure. This property will allow us to considerably enhance non-linear effects with minute quantities of material. (author)

Interactive effects of warming, eutrophication and size structure: impacts on biodiversity and food-web structure.

Science.gov (United States)

Binzer, Amrei; Guill, Christian; Rall, Björn C; Brose, Ulrich

2016-01-01

Warming and eutrophication are two of the most important global change stressors for natural ecosystems, but their interaction is poorly understood. We used a dynamic model of complex, size-structured food webs to assess interactive effects on diversity and network structure. We found antagonistic impacts: Warming increases diversity in eutrophic systems and decreases it in oligotrophic systems. These effects interact with the community size structure: Communities of similarly sized species such as parasitoid-host systems are stabilized by warming and destabilized by eutrophication, whereas the diversity of size-structured predator-prey networks decreases strongly with warming, but decreases only weakly with eutrophication. Nonrandom extinction risks for generalists and specialists lead to higher connectance in networks without size structure and lower connectance in size-structured communities. Overall, our results unravel interactive impacts of warming and eutrophication and suggest that size structure may serve as an important proxy for predicting the community sensitivity to these global change stressors. © 2015 John Wiley & Sons Ltd.

On the Internal Structure of Mobile Barchan Sand Dunes due to Granular Processes

Science.gov (United States)

Vriend, N. M.; Arran, M.; Louge, M. Y.; Hay, A. G.; Valance, A.

2017-12-01

In this work, we visualize the internal structure of mobile barchan desert dunes at the avalanche scale. We reveal an intriguing history of dune building using a novel combination of local sand sampling and advanced geophysical techniques resulting in high resolution measurements of individual avalanche events. Due to progressive rebuilding, granular avalanching, erosional and depositional processes, these marching barchan dunes are reworked every few years and a characteristic zebra-pattern (figure 1a), orientated parallel to the slipface at the angle of repose, appears at regular intervals. We present scientific data on the structure obtained from several mobile barchan dunes of different sizes during recent desert field campaigns (2014, 2015, 2017) in a mobile barchan dune field in Qatar (25.01°N, 51.34°E in the AlWakrah municipality). The site has been equipped with a weather station and has been regularly visited by a multidisciplinary research team in recent years (e.g. [1]). By applying high-frequency (1200 MHz) ground penetrating radar (GPR) transects across the midline (figure 1b) we map the continuous evolution of this cross-bedding at high resolution deep within the dune. The GPR reveals a slope reduction of the slipface near the base of the dune; evidence of irregular wind reversals; and the presence of a harder aeolian cap around the crest and extending to the brink. The data is supplemented with granulometry from layers stabilized by dyed water injection and uncovered by excavating vertical walls perpendicular to old buried avalanches. We attribute visible differences in water penetration between adjacent layers to fine particle segregation processes in granular avalanches. This work was made possible by the support of NPRP grant 6-059-2-023 from the Qatar National Research Fund to MYL and AGH, and a Royal Society Dorothy Hodgkin Research Fellowship to NMV. We thank Jean-Luc Métayer for performing detailed particle size distribution measurements

Effect of Space Vehicle Structure Vibration on Control Moment Gyroscope Dynamics

Science.gov (United States)

Dobrinskaya, Tatiana

2008-01-01

Control Moment Gyroscopes (CMGs) are used for non-propulsive attitude control of satellites and space stations, including the International Space Station (ISS). CMGs could be essential for future long duration space missions due to the fact that they help to save propellant. CMGs were successfully tested on the ground for many years, and have been successfully used on satellites. However, operations have shown that the CMG service life on the ISS is significantly shorter than predicted. Since the dynamic environment of the ISS differs greatly from the nominal environment of satellites, it was important to analyze how operations specific to the station (dockings and undockings, huge solar array motion, crew exercising, robotic operations, etc) can affect the CMG performance. This task became even more important since the first CMG failure onboard the ISS. The CMG failure resulted in the limitation of the attitude control capabilities, more propellant consumption, and additional operational issues. Therefore, the goal of this work was to find out how the vibrations of a space vehicle structure, caused by a variety of onboard operations, can affect the CMG dynamics and performance. The equations of CMG motion were derived and analyzed for the case when the gyro foundation can vibrate in any direction. The analysis was performed for unbalanced CMG gimbals to match the CMG configuration on ISS. The analysis showed that vehicle structure vibrations can amplify and significantly change the CMG motion if the gyro gimbals are unbalanced in flight. The resonance frequencies were found. It was shown that the resonance effect depends on the magnitude of gimbal imbalance, on the direction of a structure vibration, and on gimbal bearing friction. Computer modeling results of CMG dynamics affected by the external vibration are presented. The results can explain some of the CMG vibration telemetry observed on ISS. This work shows that balancing the CMG gimbals decreases the effect

Simplified analysis of frame structures with viscoelastic dampers considering the effect of soil-structure interaction

Science.gov (United States)

Zhao, Xuefei; Wang, Shuguang; Du, Dongsheng; Liu, Weiqing

2017-01-01

In this study, simplified numerical models are developed to analyze the soil-structure interaction (SSI) effect on frame structures equipped with viscoelastic dampers (VEDs) based on pile group foundation. First, a single degree-of-freedom (SDOF) oscillator is successfully utilized to replace the SDOF energy dissipated structure considering the SSI effect. The equivalent period and damping ratio of the system are obtained through analogical analysis using the frequency transfer function with adoption of the modal strain energy (MSE) technique. A parametric analysis is carried out to study the SSI effect on the performance of VEDs. Then the equilibrium equations of the multi degree-of-freedom (MDOF) structure with VEDs considering SSI effect are established in the frequency domain. Based on the assumption that the superstructure of the coupled system possesses the classical normal mode, the MDOF superstructure is decoupled to a set of individual SDOF systems resting on a rigid foundation with adoption of the MSE technique through formula derivation. Numerical results demonstrate that the proposed methods have the advantage of reducing computational cost, however, retaining the satisfactory accuracy. The numerical method proposed herein can provide a fast evaluation of the efficiency of VEDs considering the SSI effect.

The effects of Web site structure: the role of personal difference.

Science.gov (United States)

Chung, Hwiman; Ahn, Euijin

2007-12-01

This study examined the effects of Web site structures in terms of advertising effectiveness- memory, attitude, and behavioral intentions. The primary research question for this study is, What type of Web site (Web ad) structure is most effective? In the pilot study, we tested the difference between two Web site structures, linear and interactive, in terms of traditional advertising effectiveness. Results from the pilot study did not support our research expectations. However, differences in terms of memory were noted between the two structures. After re-creating the Web site based on subjects' comments, in the final experiment, we examined the differences between the two structures and the moderating role of personality difference on the effects of Web site structure. The results confirm that participants' attitude, memory, and behavioral intentions were affected differently by the different Web site structures. However, some research hypotheses were not supported by the current data.

Local Impact Simulation of SC Wall Structures using Aircraft Engine Projectile

International Nuclear Information System (INIS)

Chung, Chulhun; Lee, Jungwhee; Lee, Hanjoo; Jung, Raeyoung; Hyun, Changhun

2013-01-01

SC wall structure developed for nuclear power plant buildings consists of plain concrete and two steel plates on both surface of the concrete, while RC structure consists of re bar and concrete. SC structure has higher scabbing resistance than RC structure due to the action of steel plate on the rear side of impact. Therefore SC structure is known as more effective structure from the viewpoint of aircraft crash than RC structure. However, most of the recent researches and experiments about local impact damage deal with RC structures, and the effect of re bar and steel plate is not considered reasonably. Although Walter et al. and Make-work et al. suggested a formula for evaluating perforation depth of steel plate covered RC walls, most of the previous researches about SC structure are focused on perforation and scabbing due to the impact of hard projectile, rather than soft projectile such as an aircraft. In this research a soft projectile, i. e. aircraft engine, is utilized for impact simulation of RC and SC walls. To evaluate local damage of SC wall structures, parametric study with the variables of wall thickness and steel ratio of the cover plate is performed, and the results are compared with those of RC structures. Since scabbing was prevented by the steel plates, penetration mode of damage was observed in SC walls while scabbing damage was occurred in RC walls. It is confirmed that the rear steel plate not only contains concrete debris, but also reduces the internal damage of the concrete walls. Penetration depth of SC walls did not largely vary due to the increasing steel ratio, and similar results to RC walls were observed when the wall thickness is larger than a certain value since the impact resistance of SC wall is mainly governed by the thickness of concrete part. Therefore, it is expected that similar level of impact resistance to RC structure can be produced with the minimum thickness of steel plates of SC structure. According to these results, SC

Anaphylaxis due to caffeine

OpenAIRE

Sugiyama, Kumiya; Cho, Tatsurai; Tatewaki, Masamitsu; Onishi, Shogo; Yokoyama, Tatsuya; Yoshida, Naruo; Fujimatsu, Takayoshi; Hirata, Hirokuni; Fukuda, Takeshi; Fukushima, Yasutsugu

2015-01-01

We report a rare case of anaphylaxis due to caffeine intake. A 27-year-old woman suffered her first episode of anaphylaxis and a positive skin prick test suggested that the anaphylaxis was due to an IgE-mediated hypersensitivity reaction to caffeine. She was diagnosed with caffeine allergy and has not had an allergic reaction after avoiding foods and drinks containing caffeine. Although caffeine is known to have antiallergic effects, this case shows that caffeine can be an allergen and cause ...

New interpretation of arterial stiffening due to cigarette smoking using a structurally motivated constitutive model

DEFF Research Database (Denmark)

Enevoldsen, Majken; Henneberg, K-A; Jensen, J A

2011-01-01

these effects using a single stiffening parameter similar to the approach in isotropic continuum damage mechanics. There is a pressing need, however, for more detailed histological information coupled with more complete biaxial mechanical data for a broader range of systemic arteries....... published for rat pulmonary arteries. A structurally motivated "four fiber family" constitutive relation was used to fit the available biaxial data and associated best-fit values of material parameters were estimated using multivariate nonlinear regression. Results suggested that arterial stiffening caused...

On the structural behavior of ship's shell structures due to impact loading

Directory of Open Access Journals (Sweden)

Hyung Kyun Lim

2018-01-01

Full Text Available When collision accident between ships or between ship and offshore platform occurs, a common phenomenon that occurs in structures is the plastic deformation accompanied by a large strain such as fracture. In this study, for the rational design against accidental limit state, the plastic material constants of steel plate which is heated by line heating and steel plate formed by cold bending procedure have been defined through the numerical simulation for the high speed tension test. The usefulness of the material constants included in Cowper–Symonds model and Johnson–Cook model and the assumption that strain rate can be neglected when strain rate is less than the intermediate speed are verified through free drop test as well as comparing with numerical results in several references. This paper ends with describing the future study.

Climate change due to greenhouse effects in China as simulated by a regional climate model

Energy Technology Data Exchange (ETDEWEB)

Gao, X.J.; Zhao, Z.C.; Ding, Y.H.; Huang, R.H.; Giorgi, F. [National Climate Centre, Beijing (China)

2001-07-01

Impacts of greenhouse effects (2 x CO{sub 2}) upon climate change over China as simulated by a regional climate model over China (RegCM / China) have been investigated. The model was based on RegCM2 and was nested to a global coupled ocean-atmosphere model (CSIRO R21L9 AOGCM model). Results of the control run (1 x CO{sub 2}) indicated that simulations of surface air temperature and precipitation in China by RegCM are much better than that by the global coupled model because of a higher resolution. Results of sensitive experiment by RegCM with 2 x CO{sub 2} showed that the surface air temperature over China might increase remarkably due to greenhouse effect, especially in winter season and in North China. Precipitation might also increase in most parts of China due to the CO{sub 2} doubling.

The Effect of Anisotropy on Light Extraction of Organic Light-Emitting Diodes with Photonic Crystal Structure

Directory of Open Access Journals (Sweden)

Wei Xu

2013-01-01

Full Text Available The light extraction efficiency of organic light-emitting diodes (OLED is greatly limited due to the difference in refractive indexes between materials of OLED. We fabricated OLED with photonic crystal microstructures in the interface between the glass substrate and the ITO anode. The light extraction efficiency can be improved by utilizing photonic crystals; however, the anisotropy effect of light extraction was clearly observed in experiment. To optimize the device performance, the effect of photonic crystal on both light extraction and angular distribution was investigated using finite-difference time domain (FDTD method. We simulated the photonic crystals with the structure of square lattice and triangle lattice. We analyzed the improvement of these structures in the light extraction efficiency of the OLED and the influence of arrangement, depth, period, and diameter on anisotropy. The optimized geometric parameters were provided, which will provide the theoretical support for designing the high performance OLED.

Nonlinear response of vessel walls due to short-time thermomechanical loading

International Nuclear Information System (INIS)

Pfeiffer, P.A.; Kulak, R.F.

1994-01-01

Maintaining structural integrity of the reactor pressure vessel (RPV) during a postulated core melt accident is an important safety consideration in the design of the vessel. This study addresses the failure predictions of the vessel due to thermal and pressure loadings fro the molten core debris depositing on the lower head of the vessel. Different loading combinations were considered based on the dead load, yield stress assumptions, material response and internal pressurization. The analyses considered only short term failure (quasi static) modes, long term failure modes were not considered. Short term failure modes include plastic instabilities of the structure and failure due to exceeding the failure strain. Long term failure odes would be caused by creep rupture that leads to plastic instability of the structure. Due to the sort time durations analyzed, creep was not considered in the analyses presented

Effect of Spirulina addition on the physicochemical and structural properties of extruded snacks

Directory of Open Access Journals (Sweden)

Bárbara Franco LUCAS

Full Text Available Abstract Nowadays the demand for practical food like snacks increases worldwide, however the nutritional value in most these formulations is reduced. Due to its chemical composition with high protein concentration, the microalga Spirulina has been used on the production of enriched foods. The present study aimed to evaluate the effects of Spirulina sp. LEB 18 addition on snacks formulations and extrusion conditions on the physicochemical and structural properties of snacks. Protein concentration and physical properties such as expansion index, bulk density, hardness, water absorption index, water solubility index and color were determined. The results showed that the addition of Spirulina sp. LEB 18, temperature in the last zone of the extruder and feed moisture influenced the product responses. The increase in feed moisture increased the hardness, bulk density and water absorption index of the snacks. Higher concentrations of microalga produced snacks with higher protein content, total color difference (ΔE and compact structure. The addition of 2.6% Spirulina produced snacks with up to 11.3% protein and with adequate physical and structural properties for consumption. Thus, snacks containing Spirulina are an alternative to the demand for healthy food of practical consumption.

Founder effects and genetic population structure of brown trout (Salmo trutta) in a Danish river system

DEFF Research Database (Denmark)

Hansen, Michael Møller; Mensberg, Karen-Lise Dons

1996-01-01

The influence of founder effects on the genetic population structure of brown trout (Salmo trutta) was studied in a small Danish river system. Samples of trout from seven locations were analysed by allozyme electrophoresis and mitochondrial DNA restriction fragment length polymorphism analysis....... For comparison, allozyme data from other Danish trout populations and mtDNA data from two hatchery strains were included. Genetic differentiation among populations was found to be small but significant. Pairwise tests for homogeneity of allele and haplotype frequencies between samples showed that significance...... simulations of the influence of founder effects on mitochondrial DNA differentiation and variability showed that the observed divergence could be due either to natural founder effects or to a genetic contribution by hatchery trout. However, the allozyme results pointed towards natural founder effects...

Visual signal detection in structured backgrounds. II. Effects of contrast gain control, background variations, and white noise

Science.gov (United States)

Eckstein, M. P.; Ahumada, A. J. Jr; Watson, A. B.

1997-01-01

Studies of visual detection of a signal superimposed on one of two identical backgrounds show performance degradation when the background has high contrast and is similar in spatial frequency and/or orientation to the signal. To account for this finding, models include a contrast gain control mechanism that pools activity across spatial frequency, orientation and space to inhibit (divisively) the response of the receptor sensitive to the signal. In tasks in which the observer has to detect a known signal added to one of M different backgrounds grounds due to added visual noise, the main sources of degradation are the stochastic noise in the image and the suboptimal visual processing. We investigate how these two sources of degradation (contrast gain control and variations in the background) interact in a task in which the signal is embedded in one of M locations in a complex spatially varying background (structured background). We use backgrounds extracted from patient digital medical images. To isolate effects of the fixed deterministic background (the contrast gain control) from the effects of the background variations, we conduct detection experiments with three different background conditions: (1) uniform background, (2) a repeated sample of structured background, and (3) different samples of structured background. Results show that human visual detection degrades from the uniform background condition to the repeated background condition and degrades even further in the different backgrounds condition. These results suggest that both the contrast gain control mechanism and the background random variations degrade human performance in detection of a signal in a complex, spatially varying background. A filter model and added white noise are used to generate estimates of sampling efficiencies, an equivalent internal noise, an equivalent contrast-gain-control-induced noise, and an equivalent noise due to the variations in the structured background.

Effects of structural nonlinearity and foundation sliding on probabilistic response of a nuclear structure

International Nuclear Information System (INIS)

Hashemi, Alidad; Elkhoraibi, Tarek; Ostadan, Farhang

2015-01-01

Highlights: • Probabilistic SSI analysis including structural nonlinearity and sliding are shown. • Analysis is done for a soil and a rock site and probabilistic demands are obtained. • Structural drift ratios and In-structure response spectra are evaluated. • Structural nonlinearity significantly impacts local demands in the structure. • Sliding generally reduces seismic demands and can be accommodated in design. - Abstract: This paper examines the effects of structural nonlinearity and foundation sliding on the results of probabilistic structural analysis of a typical nuclear structure where structural nonlinearity, foundation sliding and soil-structure interaction (SSI) are explicitly included. The evaluation is carried out for a soil and a rock site at 10"4, 10"5, and 10"6 year return periods (1E − 4, 1E − 5, and 1E − 6 hazard levels, respectively). The input motions at each considered hazard level are deaggregated into low frequency (LF) and high frequency (HF) motions and a sample size of 30 is used for uncertainty propagation. The statistical distribution of structural responses including story drifts, and in-structure response spectra (ISRS) as well as foundation sliding displacements are examined. The probabilistic implementation of explicit structural nonlinearity and foundation sliding in combination with the SSI effects are demonstrated using nonlinear response history analysis (RHA) of the structure with the foundation motions obtained from elastic SSI analyses, which are applied as input to fixed-base inelastic analyses. This approach quantifies the expected structural nonlinearity and sliding for the particular structural configuration and provides a robust analytical basis for the estimation of the probabilistic distribution of selected demands parameters both at the design level and beyond design level seismic input. For the subject structure, the inclusion of foundation sliding in the analysis is found to have reduced both

Biological effects due to weak magnetic fields on plants

Science.gov (United States)

Belyavskaya, N.

In the evolution process, living organisms have experienced the action of the Earth's magnetic field (MF) that is a natural component of our environment. It is known that a galactic MF induction does not exceed 0.1 nT, since investigations of weak magnetic field (WMF) effects on biological systems have attracted attention of biologists due to planning long-term space flights to other planets where the magnetizing force is near 10-5 Oe. However, the role of WMF and its influence on organisms' functioning are still insufficiently investigated. A large number of experiments with seedlings of different plant species placed in WMF has found that the growth of their primary roots is inhibited during the early terms of germination in comparison with control. The proliferation activity and cell reproduction are reduced in meristem of plant roots under WMF application. The prolongation of total cell reproductive cycle is registered due to the expansion of G phase in1 different plant species as well as of G phase in flax and lentil roots along with2 relative stability of time parameters of other phases of cell cycle. In plant cells exposed to WMF, the decrease in functional activity of genome at early prereplicate period is shown. WMF causes the intensification in the processes of proteins' synthesis and break-up in plant roots. Qualitative and quantitative changes in protein spectrum in growing and differentiated cells of plant roots exposed to WMF are revealed. At ultrastructural level, there are observed such ultrastructural peculiarities as changes in distribution of condensed chromatin and nucleolus compactization in nuclei, noticeable accumulation of lipid bodies, development of a lytic compartment (vacuoles, cytosegresomes and paramural bodies), and reduction of phytoferritin in plastids in meristem cells of pea roots exposed to WMF. Mitochondria are the most sensitive organelle to WMF application: their size and relative volume in cells increase, matrix is electron

Flying between sky islands: the effect of naturally fragmented habitat on butterfly population structure.

Science.gov (United States)

Sekar, Sandhya; Karanth, Praveen

2013-01-01

High elevation montane areas are called "sky islands" when they occur as a series of high mountains separated by lowland valleys. Different climatic conditions at high elevations makes sky islands a specialized type of habitat, rendering them naturally fragmented compared to more continuous habitat at lower elevations. Species in sky islands face unsuitable climate in the intervening valleys when moving from one montane area to another. The high elevation shola-grassland mosaic in the Western Ghats of southern India form one such sky island complex. The fragmented patches make this area ideal to study the effect of the spatial orientation of suitable habitat patches on population genetic structure of species found in these areas. Past studies have suggested that sky islands tend to have genetically structured populations, possibly due to reduced gene flow between montane areas. To test this hypothesis, we adopted the comparative approach. Using Amplified Fragment Length Polymorphisms, we compared population genetic structures of two closely related, similar sized butterfly species: Heteropsis oculus, a high elevation shola-grassland specialist restricted to the southern Western Ghats, and Mycalesis patnia, found more continuously distributed in lower elevations. In all analyses, as per expectation the sky island specialist H. oculus exhibited a greater degree of population genetic structure than M. patnia, implying a difference in geneflow. This difference in geneflow in turn appears to be due to the natural fragmentation of the sky island complexes. Detailed analysis of a subset of H. oculus samples from one sky island complex (the Anamalais) showed a surprising genetic break. A possible reason for this break could be unsuitable conditions of higher temperature and lower rainfall in the intervening valley region. Thus, sky island species are not only restricted by lack of habitat continuity between montane areas, but also by the nature of the intervening habitat.

Changes in dermal papilla structures due to aging in the facial cheek region.

Science.gov (United States)

Mizukoshi, K; Yonekura, K; Futagawa, M; Nakamura, T; Hirayama, K; Takahashi, K

2015-05-01

In the past, it has been possible to measure the dermal papilla structures which are undulations between the epidermis and dermis by noninvasive method. However, almost all of previous studies were not intended to measure facial skin but another site of body. Here, we investigated age-dependent alterations for dermal papilla structures in the facial cheek region after elucidating the difference of characteristics between the body site. The surface of the dermis was observed under scanning electron microscope (SEM) using face and abdominal skin biopsy samples. A total of 90 Japanese women were investigated by in vivo confocal laser microscope (CLSM). The number and the shape in the horizontal cross-sectional images of the dermal papilla were analyzed. The facial skin had different characteristics in comparison to the abdominal skin by SEM observation. Under CLSM observation, we found abnormal dermal papilla structures which were accompanied by spots or enlarged pore areas and eliminated these structures from our analysis. We revealed a decrease in the number of normal dermal papilla structures with age and large individual differences at younger ages. We found abnormal dermal papilla structures and differences in the dermal papilla structures between face and other body site. With these taken into consideration, we could precisely investigate the aging alteration of normal dermal papilla structures in the face. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Separate effects tests to determine the thermal dispersion in structured pebble beds in the PBMR HPTU test facility

Energy Technology Data Exchange (ETDEWEB)

Toit, C.G. du, E-mail: jat.dutoit@nwu.ac.za; Rousseau, P.G.; Kgame, T.L.

2014-05-01

Thermal-fluid simulations are used extensively to predict the maximum fuel temperatures, flows, pressure drops and thermal capacitance of pebble bed gas cooled reactors in support of the reactor safety case. The PBMR company developed the HTTF test facility in cooperation with M-Tech Industrial (Pty) Ltd. and the North-West University in South Africa to conduct comprehensive separate effects tests as well as integrated effects tests to study the different thermal-fluid phenomena. This paper describes the separate effects tests that were conducted to determine the effect of the porous structure on the fluid effective thermal conductivity due to the thermal dispersion. It also presents the methodology applied in the data analysis to derive the resultant values of the effective thermal conductivity and its associated uncertainty.

xF 3( x,Q 2) Structure Function and Gross-Llewellyn Smith Sum Rule with Nuclear Effect and Higher Twist Correction

International Nuclear Information System (INIS)

Nath, N.M.; Mukharjee, A.; Das, M.K.; Sarma, J.K.

2016-01-01

We present an analysis of the xF 3 (x,Q 2 ) structure function and Gross-Llewellyn Smith(GLS) sum rule taking into account the nuclear effects and higher twist correction. This analysis is based on the results presented in [N.M. Nath, et al, Indian J. Phys. 90 (2016) 117]. The corrections due to nuclear effects predicted in several earlier analysis are incorporated to our results of xF 3 (x,Q 2 ) structure function and GLS sum rule for free nucleon, corrected upto next-next-to-leading order (NNLO) perturbative order and calculate the nuclear structure function as well as sum rule for nuclei. In addition, by means of a simple model we have extracted the higher twist contributions to the non-singlet structure function xF 3 (x,Q 2 ) and GLS sum rule in NNLO perturbative orders and then incorporated them to our results. Our NNLO results along with nuclear effect and higher twist corrections are observed to be compatible with corresponding experimental data and other phenomenological analysis. (paper)

Effects on Performance and Work Quality due to Low Frequency Ventilation Noise

Science.gov (United States)

Persson Waye, K.; Rylander, R.; Benton, S.; Leventhall, H. G.

1997-08-01

A pilot study was carried out to assess method evaluating effects of low frequency noise on performance. Of special interest was to study objective and subjective effects over time. Two ventilation noises were used, one of a predominantly mid frequency character and the other of a predominantly low frequency character. Both had an NC value of 35. For the study, 50 students were recruited and 30 selected on the basis of subjective reports of pressure on the eardrum after exposure to a low frequency noise. Of these, 14 randomly selected subjects aged 21 and 34 took part. The subjects performed three computerized cognitive tests in the mid frequency or the low frequency noise condition alternatively. Tests I and II were performed together with a secondary task.Questionnaires were used to evaluate subjective symptoms, effects on mood and estimated interference with the test results due to temperature, light and noise. The results showed that the subjective estimations of noise interference with performance were higher for the low frequency noise (psocial orientation (pstudied. The results further indicate that the NC curves do not fully assess the negative effects of low frequency noise on work performance.

[Pain and emotional dysregulation: Cellular memory due to pain].

Science.gov (United States)

Narita, Minoru; Watanabe, Moe; Hamada, Yusuke; Tamura, Hideki; Ikegami, Daigo; Kuzumaki, Naoko; Igarashi, Katsuhide

2015-08-01

Genetic factors are involved in determinants for the risk of psychiatric disorders, and neurological and neurodegenerative diseases. Chronic pain stimuli and intense pain have effects at a cellular and/or gene expression level, and will eventually induce "cellular memory due to pain", which means that tissue damage, even if only transient, can elicit epigenetically abnormal transcription/translation and post-translational modification in related cells depending on the degree or kind of injury or associated conditions. Such cell memory/transformation due to pain can cause an abnormality in a fundamental intracellular response, such as a change in the three-dimensional structure of DNA, transcription, or translation. On the other hand, pain is a multidimensional experience with sensory-discriminative and motivational-affective components. Recent human brain imaging studies have examined differences in activity in the nucleus accumbens between controls and patients with chronic pain, and have revealed that the nucleus accumbens plays a role in predicting the value of a noxious stimulus and its offset, and in the consequent changes in the motivational state. In this review, we provide a very brief overview of a comprehensive understanding of chronic pain associated with emotional dysregulation due to transcriptional regulation, epigenetic modification and miRNA regulation.

Dark energy and modified gravity in the Effective Field Theory of Large-Scale Structure

Science.gov (United States)

Cusin, Giulia; Lewandowski, Matthew; Vernizzi, Filippo

2018-04-01

We develop an approach to compute observables beyond the linear regime of dark matter perturbations for general dark energy and modified gravity models. We do so by combining the Effective Field Theory of Dark Energy and Effective Field Theory of Large-Scale Structure approaches. In particular, we parametrize the linear and nonlinear effects of dark energy on dark matter clustering in terms of the Lagrangian terms introduced in a companion paper [1], focusing on Horndeski theories and assuming the quasi-static approximation. The Euler equation for dark matter is sourced, via the Newtonian potential, by new nonlinear vertices due to modified gravity and, as in the pure dark matter case, by the effects of short-scale physics in the form of the divergence of an effective stress tensor. The effective fluid introduces a counterterm in the solution to the matter continuity and Euler equations, which allows a controlled expansion of clustering statistics on mildly nonlinear scales. We use this setup to compute the one-loop dark-matter power spectrum.

New interpretation of arterial stiffening due to cigarette smoking using a structurally motivated constitutive model

DEFF Research Database (Denmark)

Enevoldsen, Marie Sand; Henneberg, Kaj-Åge; Jensen, Jørgen Arendt

2011-01-01

to capture these effects using a single stiffening parameter similar to the approach in isotropic continuum damage mechanics. There is a pressing need, however, for more detailed histological information coupled with more complete biaxial mechanical data for a broader range of systemic arteries....... published for rat pulmonary arteries. A structurally motivated ‘‘four fiber family’’ constitutive relation was used to fit the available biaxial data and associated best-fit values of material parameters were estimated using multivariate nonlinear regression. Results suggested that arterial stiffening...

Finite-volume effects due to spatially non-local operators arXiv

CERN Document Server

Briceño, Raúl A.; Hansen, Maxwell T.; Monahan, Christopher J.

Spatially non-local matrix elements are useful lattice-QCD observables in a variety of contexts, for example in determining hadron structure. To quote credible estimates of the systematic uncertainties in these calculations, one must understand, among other things, the size of the finite-volume effects when such matrix elements are extracted from numerical lattice calculations. In this work, we estimate finite-volume effects for matrix elements of non-local operators, composed of two currents displaced in a spatial direction by a distance $\\xi$. We find that the finite-volume corrections depend on the details of the matrix element. If the external state is the lightest degree of freedom in the theory, e.g.~the pion in QCD, then the volume corrections scale as $ e^{-m_\\pi (L- \\xi)} $, where $m_\\pi$ is the mass of the light state. For heavier external states the usual $e^{- m_\\pi L}$ form is recovered, but with a polynomial prefactor of the form $L^m/|L - \\xi|^n$ that can lead to enhanced volume effects. These ...

Structural dynamics in FBR

International Nuclear Information System (INIS)

Bhoje, S.B.

2003-01-01

In view of thin walled large diameter shell structures with associated fluid effects, structural dynamics problems are very critical in a fast breeder reactor. Structural characteristics and consequent structural dynamics problems in typical pool type Fast Breeder Reactor are highlighted. A few important structural dynamics problems are pump induced as well as flow induced vibrations, seismic excitations, pressure transients in the intermediate heat exchangers and pipings due to a large sodium water reaction in the steam generator, and core disruptive accident loadings. The vibration problems which call for identification of excitation forces, formulation of special governing equations and detailed analysis with fluid structure interaction and sloshing effects, particularly for the components such as PSP, inner vessel, CP, CSRDM and TB are elaborated. Seismic design issues are presented in a comprehensive way. Other transient loadings which are specific to FBR, resulting from sodium-water reaction and core disruptive accident are highlighted. A few important results of theoretical as well as experimental works carried out for 500 MWe Prototype Fast Breeder Reactor (PFBR), in the domain of structural dynamics are presented. (author)

Effects of spin orbital coupling on atomic and electronic structures in Al2Cu and Al2Au crystal and liquid phases via ab initio molecular dynamics simulations

International Nuclear Information System (INIS)

Wang, Y.; Lu, Y.H.; Wang, X.D.; Cao, Q.P.; Zhang, D.X.; Jiang, J.Z.

2014-01-01

Highlights: • The SOC effect affects the cohesion energy of crystal phase. • The effect of SOC was reduced due to random local atomic structures in liquids. • The local geometrical structures also affect the melting points. • Both SOC effect and local atomic structures are important for melting point difference. - Abstract: The origin of different melting points between Al 2 Cu and Al 2 Au has been studied using ab initio molecular dynamics simulations. Cohesive energy, electronic structures and structure information of both crystal and liquid phases have been analyzed. It is found that spin orbital coupling (SOC) plays an important role on the cohesive energy of crystal phase, consistent with the different melting points of these two alloys. Whereas, it seems that SOC has no effect on the formation energy and structure of liquid phase. Possible mechanism of reduced SOC effect at liquid phase is proposed. Our results are helpful to understand the glass formation ability difference between Al 2 Cu and Al 2 Au

Thienoacene-fused pentalenes: Syntheses, structures, physical properties and applications for organic field-effect transistors

KAUST Repository

Dai, Gaole

2014-11-27

Three soluble and stable thienoacene-fused pentalene derivatives (1-3) with different π-conjugation lengths were synthesized. X-ray crystallographic analysis and density functional theory (DFT) calculations revealed their unique geometric and electronic structures due to the interaction between the aromatic thienoacene units and antiaromatic pentalene moiety. As a result, they all possess a small energy gap and show amphoteric redox behaviour. Time dependent (TD) DFT calculations were used to explain their unique electronic absorption spectra. These new compounds exhibited good thermal stability and ordered packing in solid state and thus their applications in organic field-effect transistors (OFETs) were also investigated. The highest field-effect hole mobility of 0.016, 0.036 and 0.001 cm2 V-1 s-1 was achieved for solution-processed thin films of 1-3, respectively.

Radiation damage in carbon-carbon composites: Structure and property effects

International Nuclear Information System (INIS)

Burchell, T.D.

1995-01-01

Carbon-carbon composites are an attractive choice for fusion reactor plasma facing components because of their low atomic number, superior thermal shock resistance, and low neutron activation. Next generation tokamak reactors such as the International Thermonuclear Experimental Reactor (ITER), will require high thermal conductivity carbon-carbon composites and other materials, such as beryllium, to protect their plasma facing components from the anticipated high heat fluxes. Moreover, ignition machines such as ITER will produce a large neutron flux. Consequently, the influence of neutron damage on the structure and properties of carbon-carbon composite materials must be evaluated. Data from two irradiation experiments are reported and discussed here. Carbon-carbon composite materials were irradiated in target capsules in the High Flux Isotope Reactor (HAIR) at Oak Ridge National Laboratory (ORAL). A peak damage dose of 4.7 displacements per atom (da) at an irradiation temperature of ∼600 degrees C was attained. The carbon materials irradiated here included unidirectional, two- directional, and three-directional carbon-carbon composites. Irradiation induced dimensional changes are reported for the materials and related to single crystal dimensional changes through fiber and composite structural models. Moreover, carbon-carbon composite material dimensional changes are discussed in terms of their architecture, fiber type, and graphitization temperature. Neutron irradiation induced reductions in the thermal conductivity of two, three-directional carbon-carbon composites are reported, and the recovery of thermal conductivity due to thermal annealing is demonstrated. Irradiation induced strength changes are reported for several carbon-carbon composite materials and are explained in terms of in-crystal and composite structural effects

Effects of Added Mass and Structural Damping on Dynamic Responses of a 3D Wedge Impacting on Water

Directory of Open Access Journals (Sweden)

Pengyao Yu

2018-05-01

Full Text Available The impact between the wave and the bottom of a high-speed vessel is often simplified as water-entry problems of wedges. Most investigations focus on the water entry of two dimensional (2D wedges. The effects of added mass and structural damping are still not fully investigated. By combining the normal mode method, the hydrodynamic impact model of rigid wedges and the potential flow theory, a dynamic model for predicting the response of a three dimensional (3D wedge impacting on water with a constant velocity is established in this paper. The present model can selectively consider the effects of the added mass and the structural damping. The present method has been validated through comparisons with results of published literatures and commercial software. It is found that the added mass can increase the stress response before the flow separation, and reduce the vibration frequency after the flow separation. Due to the effect of the added mass, the stress response of some positions after the flow separation is even higher than that before the flow separation. The structural damping has a negligible effect on the stress before the flow separation, but it can reduce vibration stress after the flow separation.

Assessment of structural integrity of Monju steel liner against sodium leakage and combustion. Modeling of thinning process of liner due to corrosion in structural analysis

International Nuclear Information System (INIS)

Tsukimori, K.; Kato, T.; Furuhashi, I.; Iwata, K.; Akatsu, M.

2001-01-01

The lining structure of LMFBR (Liquid Metal cooled Fast Breeder Reactor) has an important role to prohibit leaking sodium from touching a concrete floor in a sodium leakage incident. JNC (Japan Nuclear Cycle Development Institute) experienced a sodium leakage incident in 1995 in the secondary heat transport system room of the prototype LMFBR MONJU. In this incident, a part of the liner was covered with a certain amount of high temperature leaked sodium and its compounds. Visible but small distortion and thinning of the liner were detected, which were due to heating by sodium fire and chemical corrosion, respectively. To simulate the MONJU incident, JNC conducted a series of sodium leakage tests, in one of which severer corrosion (molten salt type corrosion) than that in the MONJU incident was observed. In order to secure the conservativeness in the integrity assessment of the liner, consideration of a severest corrosion process was demanded. This means that the loss of parts of the structure with time should be considered in the structural analyses. In this study a modeling of thinning process of the liner was developed in order to realize reasonable analysis from the point of view of actual phenomena. The concept of the method is to release the stress of the lost region by using artificial creep and reducing Young's modulus. The necessity of this kind of model and the validity was verified through an application analysis of the liner in the secondary heat transport system room of MONJU. (authors)

Structured-gate organic field-effect transistors

International Nuclear Information System (INIS)

Aljada, Muhsen; Pandey, Ajay K; Velusamy, Marappan; Burn, Paul L; Meredith, Paul; Namdas, Ebinazar B

2012-01-01

We report the fabrication and electrical characteristics of structured-gate organic field-effect transistors consisting of a gate electrode patterned with three-dimensional pillars. The pillar gate electrode was over-coated with a gate dielectric (SiO 2 ) and solution processed organic semiconductors producing both unipolar p-type and bipolar behaviour. We show that this new structured-gate architecture delivers higher source-drain currents, higher gate capacitance per unit equivalent linear channel area, and enhanced charge injection (electrons and/or holes) versus the conventional planar structure in all modes of operation. For the bipolar field-effect transistor (FET) the maximum source-drain current enhancements in p- and n-channel mode were >600% and 28%, respectively, leading to p and n charge mobilities with the same order of magnitude. Thus, we have demonstrated that it is possible to use the FET architecture to manipulate and match carrier mobilities of material combinations where one charge carrier is normally dominant. Mobility matching is advantageous for creating organic logic circuit elements such as inverters and amplifiers. Hence, the method represents a facile and generic strategy for improving the performance of standard organic semiconductors as well as new materials and blends. (paper)

Structured-gate organic field-effect transistors

Science.gov (United States)

Aljada, Muhsen; Pandey, Ajay K.; Velusamy, Marappan; Burn, Paul L.; Meredith, Paul; Namdas, Ebinazar B.

2012-06-01

We report the fabrication and electrical characteristics of structured-gate organic field-effect transistors consisting of a gate electrode patterned with three-dimensional pillars. The pillar gate electrode was over-coated with a gate dielectric (SiO2) and solution processed organic semiconductors producing both unipolar p-type and bipolar behaviour. We show that this new structured-gate architecture delivers higher source-drain currents, higher gate capacitance per unit equivalent linear channel area, and enhanced charge injection (electrons and/or holes) versus the conventional planar structure in all modes of operation. For the bipolar field-effect transistor (FET) the maximum source-drain current enhancements in p- and n-channel mode were >600% and 28%, respectively, leading to p and n charge mobilities with the same order of magnitude. Thus, we have demonstrated that it is possible to use the FET architecture to manipulate and match carrier mobilities of material combinations where one charge carrier is normally dominant. Mobility matching is advantageous for creating organic logic circuit elements such as inverters and amplifiers. Hence, the method represents a facile and generic strategy for improving the performance of standard organic semiconductors as well as new materials and blends.

Pounding effects during an earthquake, with and without consideration of soil‑structure interaction

Directory of Open Access Journals (Sweden)

Daniela DOBRE

2015-07-01

Full Text Available The pounding between adjacent buildings can cause both architectural and structural damages. The paper presents some aspects related to the Vrancea seismic motions pattern, a review of observed damages after a strong earthquake due to pounding of buildings in Romania, a few causes of pounding, an analytical and numerical modeling study. For the behavior of buildings under structural pounding, an analysis with and without consideration of soil-structure interaction is done.

Work structure, organizational communication, and organizational effectiveness

International Nuclear Information System (INIS)

Van Cott, H.P.; Bauman, M.B.

1986-01-01

This paper describes the assessment of the work structure and organizational communication in nuclear power plants. Questionnaires were given to a cross-section of plant personnel, and structured ''critical incident'' interviews were conducted to verify the questionnaire results. The data showed that a variety of work structure factor problem areas do exist in nuclear power plants. This paper highlights many aspects of organizational communication found to be problematic, and identifies weak links in the chain of coordination and information processing required to effectively perform corrective and preventive maintenance in the plants

Potential fluctuations due to randomly distributed charges at the semiconductor-insulator interface in MIS-structures

International Nuclear Information System (INIS)

Yanchev, I.

2003-01-01

A new expression for the Fourier transform of the binary correlation function of the random potential near the semiconductor-insulator interface is derived. The screening from the metal electrode in MIS-structure is taken into account introducing an effective insulator thickness. An essential advantage of this correlation function is the finite dispersion of the random potential to which it leads in distinction with the so far known correlation functions leading to a divergent dispersion. The dispersion, an important characteristic of the random potential distribution, determining the amplitude of the potential fluctuations is calculated

Potential fluctuations due to randomly distributed charges at the semiconductor-insulator interface in MIS-structures

CERN Document Server

Yanchev, I

2003-01-01

A new expression for the Fourier transform of the binary correlation function of the random potential near the semiconductor-insulator interface is derived. The screening from the metal electrode in MIS-structure is taken into account introducing an effective insulator thickness. An essential advantage of this correlation function is the finite dispersion of the random potential to which it leads in distinction with the so far known correlation functions leading to a divergent dispersion. The dispersion, an important characteristic of the random potential distribution, determining the amplitude of the potential fluctuations is calculated.

Potential fluctuations due to randomly distributed charges at the semiconductor-insulator interface in MIS-structures

Energy Technology Data Exchange (ETDEWEB)

Yanchev, I

2003-07-01

A new expression for the Fourier transform of the binary correlation function of the random potential near the semiconductor-insulator interface is derived. The screening from the metal electrode in MIS-structure is taken into account introducing an effective insulator thickness. An essential advantage of this correlation function is the finite dispersion of the random potential to which it leads in distinction with the so far known correlation functions leading to a divergent dispersion. The dispersion, an important characteristic of the random potential distribution, determining the amplitude of the potential fluctuations is calculated.

Effects of air pollutants on epicuticular wax structure

International Nuclear Information System (INIS)

Huttunen, S.

1994-01-01

In xerophytes, like conifers, the epicuticular wax is well developed. Especially in and around stomatal entrances, a thick wax coating is present. Epicuticular waxes are modified by changes in plant growth conditions such as temperature, relative humidity, irradiance, and wind, or acid rain. The fine structure of epicuticular waxes, their chemistry, and ecophysiological function are modified, especially in evergreen, long-lived conifer needles with characteristic crystalline wax structures. During needle flushing and development, wax structure is easily modified. Acid rain-treated Scots pine needles had 50% less epicuticular waxes in early August. Pollution-induced delayed development, destruction, and disturbances have been identified in many plant species. The structural changes in wax crystals are known. Acid rain or polluted air can destroy the crystalloid epicuticular waxes in a few weeks. In Pinus sylvestris, the first sign of pollution effect is the fusion of wax tubes. In Picea abies and P. sitchensis, modifications of crystalloid wax structure are known. In Californian pine trees phenomena of recrystallization of wax tubes on second-year needles were observed after delayed epicuticular wax development in Pinus ponderosa and P. coulteri. Thus, the effects of air pollutants are modified by climate. Accelerated senescence of leaves and needles have been associated with natural and anthropogenic stresses. The accelerated erosion rate of epicuticular waxes has been measured under air pollution conditions. Many short-term air pollution experiments have failed to show any structural changes in epicuticular wax structures. The quantity and quality of needle waxes grown in open-top chambers, glass houses, or polluted air before treatment, differ from field conditions and make it difficult to detect effects of any treatment. (orig.)

Giant Faraday effect due to Pauli exclusion principle in 3D topological insulators.

Science.gov (United States)

Paudel, Hari P; Leuenberger, Michael N

2014-02-26

Experiments using ARPES, which is based on the photoelectric effect, show that the surface states in 3D topological insulators (TI) are helical. Here we consider Weyl interface fermions due to band inversion in narrow-bandgap semiconductors, such as Pb1-xSnxTe. The positive and negative energy solutions can be identified by means of opposite helicity in terms of the spin helicity operator in 3D TI as ĥ(TI) = (1/ |p|_ |) β (σ|_ x p|_ ) · z^, where β is a Dirac matrix and z^ points perpendicular to the interface. Using the 3D Dirac equation and bandstructure calculations we show that the transitions between positive and negative energy solutions, giving rise to electron-hole pairs, obey strict optical selection rules. In order to demonstrate the consequences of these selection rules, we consider the Faraday effect due to the Pauli exclusion principle in a pump-probe setup using a 3D TI double interface of a PbTe/Pb₀.₃₁Sn₀.₆₉Te/PbTe heterostructure. For that we calculate the optical conductivity tensor of this heterostructure, which we use to solve Maxwell's equations. The Faraday rotation angle exhibits oscillations as a function of probe wavelength and thickness of the heterostructure. The maxima in the Faraday rotation angle are of the order of mrds.

Field Observation of Soil Displacements Resulting Due Unsupported Excavation and Its Effects on Proposed Adjacent Piles

Directory of Open Access Journals (Sweden)

Ala Nasir Al-Jorany

2016-06-01

Full Text Available Soil movement resulting due unsupported excavation nearby axially loaded piles imposes significant structural troubles on geotechnical engineers especially for piles that are not designed to account for loss of lateral confinement. In this study the field excavation works of 7.0 m deep open tunnel was continuously followed up by the authors. The work is related to the project of developing the Army canal in the east of Baghdad city in Iraq. A number of selected points around the field excavation are installed on the ground surface at different horizontal distance. The elevation and coordinates of points are recorded during 23 days with excavation progress period. The field excavation process was numerically simulated by using the finite element package PLAXIS 3D foundation. The obtained analysis results regarding the displacements of the selected points are compared with the field observation for verification purpose. Moreover, finite element analysis of axially loaded piles that are presumed to be existed at the locations of the observation points is carried out to study the effect of excavation on full scale piles behaviors. The field observation monitored an upward movement and positive lateral ground movement for shallow excavation depth. Later on and as the excavation process went deeper, a downward movement and negative lateral ground movement are noticed. The analyses results are in general well agreed with the monitored values of soil displacements at the selected points. It is found also that there are obvious effects of the nearby excavation on the presumed piles in terms of displacements and bending moments.

Modeling and analysis of aging behavior of concrete structures in nuclear power plants

Energy Technology Data Exchange (ETDEWEB)

Rashid, J.Y.R.; James, R.J.; Dunham, R.S. [ANATECH (United States)

2011-07-01

As nuclear power plants approach the end of their original design life and begin to transition to the life extension phase, consideration has to be given to the effects of structural aging when evaluating the extended operation of reinforced or pre-stressed concrete structures. The behavior of concrete is highly nonlinear, having low tensile strength, shear stiffness and strength that depend on crack widths, and a confinement-dependent compressive elasto-plasticity. A concrete material model is described having the appropriate capabilities required for evaluating structural aging. The model treats reinforced concrete as a three-phase composite: plain concrete material as a three-dimensional continuum phase, steel reinforcement (rebar) as a uni-directional phase, and a rebar-concrete interaction phase. Structural aging is defined as the combined effects of time dependent material properties degradation and service induced changes in loading and operational conditions. Three broad categories of structural aging, and the interaction between them, are considered: 1) Aging effects due to expected time dependent changes in material properties, 2) Aging effects due to unexpected time dependent material degradation, and 3) Aging effects due to operational environment and loading. Example analyses are presented which illustrate the value of using advanced modeling and simulation in evaluating expected and unusual structural behavior. This is particularly important for safety structures that are approaching the end of their design life and are facing the prospect of re-licensing for extended operation

Soil-structure interaction effects on the reliability evaluation of reactor containments

International Nuclear Information System (INIS)

Pires, J.; Hwang, H.; Reich, M.

1986-01-01

The probability-based method for the seismic reliability assessment of nuclear structures, which has been developed at Brookhaven National Laboratory (BNL), is extended to include the effects of soil-structure interaction. A reinforced concrete containment building is analyzed in order to examine soil-structure interaction effects on: (1) structural fragilities; (2) floor response spectra statistics; and (3) correlation coefficients for total acceleration responses at specified structural locations

Ecological and evolutionary effects of stickleback on community structure.

Directory of Open Access Journals (Sweden)

Simone Des Roches

Full Text Available Species' ecology and evolution can have strong effects on communities. Both may change concurrently when species colonize a new ecosystem. We know little, however, about the combined effects of ecological and evolutionary change on community structure. We simultaneously examined the effects of top-predator ecology and evolution on freshwater community parameters using recently evolved generalist and specialist ecotypes of three-spine stickleback (Gasterosteus aculeatus. We used a mesocosm experiment to directly examine the effects of ecological (fish presence and density and evolutionary (phenotypic diversity and specialization factors on community structure at lower trophic levels. We evaluated zooplankton biomass and composition, periphyton and phytoplankton chlorophyll-a concentration, and net primary production among treatments containing different densities and diversities of stickleback. Our results showed that both ecological and evolutionary differences in the top-predator affect different aspects of community structure and composition. Community structure, specifically the abundance of organisms at each trophic level, was affected by stickleback presence and density, whereas composition of zooplankton was influenced by stickleback diversity and specialization. Primary productivity, in terms of chlorophyll-a concentration and net primary production was affected by ecological but not evolutionary factors. Our results stress the importance of concurrently evaluating both changes in density and phenotypic diversity on the structure and composition of communities.

Structure functions of hadrons in the QCD effective theory

International Nuclear Information System (INIS)

Shigetani, Takayuki

1996-01-01

We study the structure functions of hadrons with the low energy effective theory of QCD. We try to clarify a link between the low energy effective theory, where non-perturbative dynamics is essential, and the high energy deep inelastic scattering experiment. We calculate the leading twist matrix elements of the structure function at the low energy model scale within the effective theory. Calculated structure functions are evoluted to the high momentum scale with the help of the perturbative QCD, and compared with the experimental data. Through the comparison of the model calculations with the experiment, we discuss how the non-perturbative dynamics of the effective theory is reflected in the deep inelastic phenomena. We first evaluate the structure functions of the pseudoscalar mesons using the NJL model. The resulting structure functions show reasonable agreements with experiments. We study then the quark distribution functions of the nucleon using a covariant quark-diquark model. We calculate three leading twist distribution functions, spin-independent f 1 (x), longitudinal spin distribution g 1 (x), and chiral-odd transversity spin distribution h 1 (x). The results for f 1 (x) and g 1 (x) turn out to be consistent with available experiments because of the strong spin-0 diquark correlation. (author)

Self-Sensing Concrete Nanocomposites for Smart Structures

OpenAIRE

A. D'Alessandro; F. Ubertini; A. L. Materazzi

2016-01-01

In the field of civil engineering, Structural Health Monitoring is a topic of growing interest. Effective monitoring instruments permit the control of the working conditions of structures and infrastructures, through the identification of behavioral anomalies due to incipient damages, especially in areas of high environmental hazards as earthquakes. While traditional sensors can be applied only in a limited number of points, providing a partial information for a structural diagnosis, novel tr...

Coal mining activities change plant community structure due to air pollution and soil degradation.

Science.gov (United States)

Pandey, Bhanu; Agrawal, Madhoolika; Singh, Siddharth

2014-10-01

The aim of this study was to investigate the effects of coal mining activities on the community structures of woody and herbaceous plants. The response of individual plants of community to defilement caused by coal mining was also assessed. Air monitoring, soil physico-chemical and phytosociological analyses were carried around Jharia coalfield (JCF) and Raniganj coalfield. The importance value index of sensitive species minified and those of tolerant species enhanced with increasing pollution load and altered soil quality around coal mining areas. Although the species richness of woody and herbaceous plants decreased with higher pollution load, a large number of species acclimatized to the stress caused by the coal mining activities. Woody plant community at JCF was more affected by coal mining than herbaceous community. Canonical correspondence analysis revealed that structure of herbaceous community was mainly driven by soil total organic carbon, soil nitrogen, whereas woody layer community was influenced by sulphur dioxide in ambient air, soil sulphate and soil phosphorus. The changes in species diversity observed at mining areas indicated an increase in the proportion of resistant herbs and grasses showing a tendency towards a definite selection strategy of ecosystem in response to air pollution and altered soil characteristics.

Plasma effects on subcellular structures

International Nuclear Information System (INIS)

Gweon, Bomi; Kim, Dan Bee; Jung, Heesoo; Choe, Wonho; Kim, Daeyeon; Shin, Jennifer H.

2010-01-01

Atmospheric pressure helium plasma treated human hepatocytes exhibit distinctive zones of necrotic and live cells separated by a void. We propose that plasma induced necrosis is attributed to plasma species such as oxygen radicals, charged particles, metastables and/or severe disruption of charged cytoskeletal proteins. Interestingly, uncharged cytoskeletal intermediate filaments are only minimally disturbed by plasma, elucidating the possibility of plasma induced electrostatic effects selectively destroying charged proteins. These bona fide plasma effects, which inflict alterations in specific subcellular structures leading to necrosis and cellular detachment, were not observed by application of helium flow or electric field alone.

Wannier–Stark electro-optical effect, quasi-guided and photonic modes in 2D macroporous silicon structures with SiO_2 coatings

International Nuclear Information System (INIS)

Karachevtseva, L.; Goltviansky, Yu.; Sapelnikova, O.; Lytvynenko, O.; Stronska, O.; Bo, Wang; Kartel, M.

2016-01-01

Highlights: • The IR absorption spectra of oxidized macroporous silicon were studied. • The Wannier–Stark electro-optical effect on Si-SiO_2 boundary was confirmed. • An additional electric field of quasi-guided optical modes was evaluated. • The photonic modes and band gaps were measured as peculiarities in absorption spectra. - Abstract: Opportunities to enhance the properties of structured surfaces were demonstrated on 2D macroporous silicon structures with SiO_2 coatings. We investigated the IR light absorption oscillations in macroporous silicon structures with SiO2 coatings 0–800 nm thick. The Wannier–Stark electro-optical effect due to strong electric field on Si-SiO_2boundary and an additional electric field of quasi-guided optical modes were taken into account. The photonic modes and band gaps were also considered as peculiarities in absorbance spectra of macroporous silicon structures with a thick SiO_2 coating. The photonic modes do not coincide with the quasi-guided modes in the silicon matrix and do not appear in absorption spectra of 2D macroporous silicon structures with surface nanocrystals.

Effects of macroeconomic trends on social security spending due to sickness and disability.

Science.gov (United States)

Khan, Jahangir; Gerdtham, Ulf-G; Jansson, Bjarne

2004-11-01

We analyzed the relationship between macroeconomic conditions, measured as unemployment rate and social security spending, from 4 social security schemes and total spending due to sickness and disability. We obtained aggregated panel data from 13 Organization for Economic Cooperation and Development member countries for 1980-1996. We used regression analysis and fixed effect models to examine spending on sickness benefits, disability pensions, occupational-injury benefits, survivor's pensions, and total spending. A decline in unemployment increased sickness benefits spending and reduced disability pension spending. These effects reversed direction after 4 years of unemployment. Inclusion of mortality rate as an additional variable in the analysis did not affect the findings. Macroeconomic conditions influence some reimbursements from social security schemes but not total spending.

Effect of Population Structure Change on Carbon Emission in China

Directory of Open Access Journals (Sweden)

Wen Guo

2016-03-01

Full Text Available This paper expanded the Logarithmic Mean Divisia Index (LMDI model through the introduction of urbanization, residents’ consumption, and other factors, and decomposed carbon emission changes in China into carbon emission factor effect, energy intensity effect, consumption inhibitory factor effect, urbanization effect, residents’ consumption effect, and population scale effect, and then explored contribution rates and action mechanisms of the above six factors on change in carbon emissions in China. Then, the effect of population structure change on carbon emission was analyzed by taking 2003–2012 as a sample period, and combining this with the panel data of 30 provinces in China. Results showed that in 2003–2012, total carbon emission increased by 4.2117 billion tons in China. The consumption inhibitory factor effect, urbanization effect, residents’ consumption effect, and population scale effect promoted the increase in carbon emissions, and their contribution ratios were 27.44%, 12.700%, 74.96%, and 5.90%, respectively. However, the influence of carbon emission factor effect (−2.54% and energy intensity effect (−18.46% on carbon emissions were negative. Population urbanization has become the main population factor which affects carbon emission in China. The “Eastern aggregation” phenomenon caused the population scale effect in the eastern area to be significantly higher than in the central and western regions, but the contribution rate of its energy intensity effect (−11.10 million tons was significantly smaller than in the central (−21.61 million tons and western regions (−13.29 million tons, and the carbon emission factor effect in the central area (−3.33 million tons was significantly higher than that in the eastern (−2.00 million tons and western regions (−1.08 million tons. During the sample period, the change in population age structure, population education structure, and population occupation structure

Steel Processing Properties and Their Effect on Impact Deformation of Lightweight Structures

Energy Technology Data Exchange (ETDEWEB)

Simunovic, S

2003-09-23

The objective of the research was to perform a comprehensive computational analysis of the effects of material and process modeling approaches on performance of UltraLight Steel Auto Body (ULSAB) vehicle models. The research addressed numerous material related effects, impact conditions as well as analyzed the performance of the ULSAB vehicles in crashes against designs representing the current US vehicle fleet. This report is organized into three main sections. The first section describes the results of the computational analysis of ULSAB crash simulations that were performed using advanced material modeling techniques. The effects of strain-rate sensitivity on a high strength steel (HSS) intensive vehicle were analyzed. Frontal and frontal offset crash scenarios were used in a finite element parametric study of the ULSAB body structure. Comparisons are made between the crash results using the piece-wise-linear isotropic plasticity strain-rate dependent material model, and the isotropic plasticity material model based on quasi-static properties. The simulation results show the importance of advanced material modeling techniques for vehicle crash simulations due to strain-rate sensitivity and rapid hardening characteristics of advanced high strength steels. Material substitution was investigated for the main frontal crush structure using the material of similar yield stress a significantly different strain-rate and hardening characteristics. The objective of the research presented in Section 2 was to assess the influence of stamping process on crash response of ULSAB vehicle. Considered forming effects included thickness variations and plastic strain hardening imparted in the part forming process. The as-formed thickness and plastic strain for front crash parts were used as input data for vehicle crash analysis. Differences in structural performance between crash models with and without forming data were analyzed in order to determine the effects and feasibility of

Heat treatment and aging effect on the structural and optical properties of plasma polymerized 2,6-diethylaniline thin films

International Nuclear Information System (INIS)

Matin, Rummana; Bhuiyan, A.H.

2012-01-01

The monomer, 2,6-diethylaniline has been used to deposit plasma polymerized 2,6-diethylaniline (PPDEA) thin films at room temperature on to glass substrates by a capacitively coupled parallel plate glow discharge reactor. A comparative analysis on the changes of morphological, structural and optical properties of as-deposited, heat treated and aged PPDEA thin films is ascertained. Scanning electron microscopy shows uniform and pinhole free surface of PPDEA thin films and no significant difference in the surface morphology is observed due to heat treatment. Electron dispersive X-ray and Fourier transform infrared spectroscopic investigations indicate some structural rearrangement in PPDEA thin films due to heat treatment. Differential thermal analysis, thermogravimetric analysis and differential thermogravimetric analysis suggest that the PPDEA is thermally stable up to about 580 K. The study on the optical absorption spectra of as-deposited, heat treated and aged PPDEA thin films of different thicknesses lead to the determination of the allowed direct and indirect transition energies ranging from 3.63 to 2.73 and 2.38 to 1.26 eV respectively. Urbach energy, steepness parameter and extinction coefficient are also assessed. It is observed that the optical parameters of as-deposited PPDEA thin films change due to heat treatment and do not change appreciably due to aging. - Highlights: ► Heat treatment and aging effect of plasma polymerized 2,6-diethylaniline thin films. ► The surface morphology of PPDEA is found uniform for all types of sample. ► Heat treatment introduces some elemental and structural rearrangement. ► The thermal stability is found up to about 580 K. ► Optical parameters were changed for heat treatment but not markedly for aging.

Surface behaviour of first-wall materials due to the synergistic effect of helium and hydrogen isotopes

International Nuclear Information System (INIS)

Abramov, E.; Moreno, D.; Solovioff, G.; Eliezer, D.

1994-01-01

Scanning electron microscopy has been used to investigate changes in surface morphology due to helium implantation and hydrogen charging. Pure polycrystalline nickel, OFHC copper and Cu-1.8Be-0.2Co (CAD 172) alloy have been studied. The influence of helium implantation parameters on blister formation and growth was investigated. Hydrogen charging (cathodic or thermal-gas) was found to lower the helium content needed for blistering and surface exfoliation. The effect of heating, carried out after hydrogen charging, was also studied. For the copper samples, hydrogen damage was produced by oxide reduction at the oxide-metal interface. This damage was found to be lower when the sputtering due to helium implantation increased. The CuBe alloy showed a greater hydrogen resistance due to the stability of the surface BeO. ((orig.))

Growth, Employment and Structural Change

DEFF Research Database (Denmark)

Aggarwal, Aradhna

2016-01-01

This paper studies the decomposition of GSDP growth per capita in Punjab via-a-vis 15 other states in India during 1993–94 and 2011–12 in terms of employment and productivity growth. Specifically, it focuses on the role of employment growth and structural change in employment on economic growth...... but structural shifts have paid off well in terms of diversification of the economy and their contribution to labour productivity especially for manufacturing. Overall employment effect had been negative but this was essentially due to contraction in the labour force; the employment rate effect turned out...

System Reliability of Timber Structures

DEFF Research Database (Denmark)

Kirkegaard, Poul Henning; Sørensen, John Dalsgaard

2010-01-01

elements, alternate load path(s) etc. in the structural design. In general these characteristics can have a positive influence on system reliability of a structure however, in Eurocodes ductility is only awarded for concrete and steel structures but not for timber structures. It is well......-know that structural systems can redistribute internal forces due to ductility of a connection, i.e. some additional loads can be carried by the structure. The same effect is also possible for reinforced concrete structures and structures of steel. However, for timber structures codes do not award that ductility......For reduction of the risk of collapse in the event of loss of structural element(s), a structural engineer may take necessary steps to design a collapse-resistant structure that is insensitive to accidental circumstances e.g. by incorporating characteristics like redundancy, ties, ductility, key...

Brain structural plasticity with spaceflight.

Science.gov (United States)

Koppelmans, Vincent; Bloomberg, Jacob J; Mulavara, Ajitkumar P; Seidler, Rachael D

2016-01-01

Humans undergo extensive sensorimotor adaptation during spaceflight due to altered vestibular inputs and body unloading. No studies have yet evaluated the effects of spaceflight on human brain structure despite the fact that recently reported optic nerve structural changes are hypothesized to occur due to increased intracranial pressure occurring with microgravity. This is the first report on human brain structural changes with spaceflight. We evaluated retrospective longitudinal T2-weighted MRI scans and balance data from 27 astronauts (thirteen ~2-week shuttle crew members and fourteen ~6-month International Space Station crew members) to determine spaceflight effects on brain structure, and whether any pre to postflight brain changes are associated with balance changes. Data were obtained from the NASA Lifetime Surveillance of Astronaut Health. Brain scans were segmented into gray matter maps and normalized into MNI space using a stepwise approach through subject specific templates. Non-parametric permutation testing was used to analyze pre to postflight volumetric gray matter changes. We found extensive volumetric gray matter decreases, including large areas covering the temporal and frontal poles and around the orbits. This effect was larger in International Space Station versus shuttle crew members in some regions. There were bilateral focal gray matter increases within the medial primary somatosensory and motor cortex; i.e., the cerebral areas where the lower limbs are represented. These intriguing findings are observed in a retrospective data set; future prospective studies should probe the underlying mechanisms and behavioral consequences.

Key Techniques on Preparing High Aspect Ratio Micro and Nano Structures

DEFF Research Database (Denmark)

Jian, Zhao; Lianhe, Dong; Xiaoli, Zhu

2016-01-01

effectively. The mechanism of action between NaCl and HSQ was analyzed. The collapse and adhesion of resist structure due to the effect of gas-liquid interfacial capillary surface tension were suppressed by the CO2 supercritical drying method. Large-area dense nano-structures with the aspect ratio of 12...

Nuclear structure and fusion at the barrier

International Nuclear Information System (INIS)

Reisdorf, W.

1985-01-01

A comparative study of measured fusion excitation functions in the vicinity of the barrier reveals nuclear structure effects, due in particular to the coupling of the fusion process to direct-reaction channels. (orig.)

Structure Effects of 2D Materials on α-Nickel Hydroxide for Oxygen Evolution Reaction.

Science.gov (United States)

Luan, Chenglong; Liu, Guangli; Liu, Yujie; Yu, Lei; Wang, Yao; Xiao, Yun; Qiao, Hongyan; Dai, Xiaoping; Zhang, Xin

2018-04-24

To engineer low-cost, high-efficiency, and stable oxygen evolution reaction (OER) catalysts, structure effects should be primarily understood. Focusing on this, we systematically investigated the relationship between structures of materials and their OER performances by taking four 2D α-Ni(OH) 2 as model materials, including layer-stacked bud-like Ni(OH) 2 -NB, flower-like Ni(OH) 2 -NF, and petal-like Ni(OH) 2 -NP as well as the ultralarge sheet-like Ni(OH) 2 -NS. For the first three (layer-stacking) catalysts, with the decrease of stacked layers, their accessible surface areas, abilities to adsorb OH - , diffusion properties, and the intrinsic activities of active sites increase, which accounts for their steadily enhanced activity. As expected, Ni(OH) 2 -NP shows the lowest overpotential (260 mV at 10 mA cm -2 ) and Tafel slope (78.6 mV dec -1 ) with a robust stability over 10 h among the samples, which also outperforms the benchmark IrO 2 (360 mV and 115.8 mV dec -1 ) catalyst. Interestingly, Ni(OH) 2 -NS relative to Ni(OH) 2 -NP exhibits even faster substance diffusion due to the sheet-like structure, but shows inferior OER activity, which is mainly because the Ni(OH) 2 -NP with a smaller size possesses more active boundary sites (higher reactivity of active sites) than Ni(OH) 2 -NS, considering the adsorption properties and accessible surface areas of the two samples are quite similar. By comparing the different structures and their OER behaviors of four α-Ni(OH) 2 samples, our work may shed some light on the structure effect of 2D materials and accelerate the development of efficient OER catalysts.

SnTe field effect transistors and the anomalous electrical response of structural phase transition

International Nuclear Information System (INIS)

Li, Haitao; Zhu, Hao; Yuan, Hui; Li, Qiliang; You, Lin; Kopanski, Joseph J.; Richter, Curt A.; Zhao, Erhai

2014-01-01

SnTe is a conventional thermoelectric material and has been newly found to be a topological crystalline insulator. In this work, back-gate SnTe field-effect transistors have been fabricated and fully characterized. The devices exhibit n-type transistor behaviors with excellent current-voltage characteristics and large on/off ratio (>10 6 ). The device threshold voltage, conductance, mobility, and subthreshold swing have been studied and compared at different temperatures. It is found that the subthreshold swings as a function of temperature have an apparent response to the SnTe phase transition between cubic and rhombohedral structures at 110 K. The abnormal and rapid increase in subthreshold swing around the phase transition temperature may be due to the soft phonon/structure change which causes the large increase in SnTe dielectric constant. Such an interesting and remarkable electrical response to phase transition at different temperatures makes the small SnTe transistor attractive for various electronic devices.

Turbulent momentum transport due to neoclassical flows

International Nuclear Information System (INIS)

Lee, Jungpyo; Barnes, Michael; Parra, Felix I; Belli, Emily; Candy, Jeff

2015-01-01

Intrinsic toroidal rotation in a tokamak can be driven by turbulent momentum transport due to neoclassical flow effects breaking a symmetry of turbulence. In this paper we categorize the contributions due to neoclassical effects to the turbulent momentum transport, and evaluate each contribution using gyrokinetic simulations. We find that the relative importance of each contribution changes with collisionality. For low collisionality, the dominant contributions come from neoclassical particle and parallel flows. For moderate collisionality, there are non-negligible contributions due to neoclassical poloidal electric field and poloidal gradients of density and temperature, which are not important for low collisionality. (paper)

Three novel approaches to structural identifiability analysis in mixed-effects models.

Science.gov (United States)

Janzén, David L I; Jirstrand, Mats; Chappell, Michael J; Evans, Neil D

2016-05-06

Structural identifiability is a concept that considers whether the structure of a model together with a set of input-output relations uniquely determines the model parameters. In the mathematical modelling of biological systems, structural identifiability is an important concept since biological interpretations are typically made from the parameter estimates. For a system defined by ordinary differential equations, several methods have been developed to analyse whether the model is structurally identifiable or otherwise. Another well-used modelling framework, which is particularly useful when the experimental data are sparsely sampled and the population variance is of interest, is mixed-effects modelling. However, established identifiability analysis techniques for ordinary differential equations are not directly applicable to such models. In this paper, we present and apply three different methods that can be used to study structural identifiability in mixed-effects models. The first method, called the repeated measurement approach, is based on applying a set of previously established statistical theorems. The second method, called the augmented system approach, is based on augmenting the mixed-effects model to an extended state-space form. The third method, called the Laplace transform mixed-effects extension, is based on considering the moment invariants of the systems transfer function as functions of random variables. To illustrate, compare and contrast the application of the three methods, they are applied to a set of mixed-effects models. Three structural identifiability analysis methods applicable to mixed-effects models have been presented in this paper. As method development of structural identifiability techniques for mixed-effects models has been given very little attention, despite mixed-effects models being widely used, the methods presented in this paper provides a way of handling structural identifiability in mixed-effects models previously not

The Effects of Doping Copper and Mesoporous Structure on Photocatalytic Properties of TiO2

Directory of Open Access Journals (Sweden)

Yang Wang

2014-01-01

Full Text Available This paper describes a system for the synthesis of Cu-doped mesoporous TiO2 nanoparticles by a hydrothermal method at relatively low temperatures. The technique used is to dope the as-prepared mesoporous TiO2 system with copper. In this method, the copper species with the form of Cu1+, which was attributed to the reduction effect of dehydroxylation and evidenced by X-ray photoelectron spectroscopy (XPS and X-ray diffraction (XRD, was well dispersed in the optimal concentration 1 wt.% Cu-doped mesoporous TiO2. In this as-prepared mesoporous TiO2 system, original particles with a size of approximately 20 nm are aggregated together to shapes of approximately 1100 nm, which resulted in the porous aggregate structure. More importantly, the enhancement of the photocatalytic activity was discussed as effects due to the formation of stable Cu(I and the mesoporous structure in the Cu-doped mesoporous TiO2. Among them, Cu-doped mesoporous TiO2 shows the highest degradation rate of methyl orange (MO. In addition, the effects of initial solution pH on degradation of MO had also been investigated. As a result, the optimum values of initial solution pH were found to be 3.

Study of the early age cracking of concrete massive structures: effect of the temperature decrease rate, steel reinforcement and construction joints

International Nuclear Information System (INIS)

Briffaut, M.

2010-01-01

At early-age, massive concrete structures (ex. nuclear power plant) are submitted to strains due to the hydration reaction. If they are restrained, crossing cracks can occurs. This cracking may increase significantly the concrete wall permeability. The objectives of this work was to characterize the early age concrete behavior (thermal and endogenous shrinkage, basic and thermal transient creep, mechanical characteristic evolution) as well as develop a new device to study the early age cracking of a concrete structure submitted to restrained shrinkage. The experimental campaign achieved with this new device (called thermal active ring test) and the numerical analysis of the test thanks to finite element simulations allows us to evaluate the coupling between creep and damage, to identify the tensile strength decrease due to construction joints and to quantify the effect of reinforcement on the concrete behaviour. Moreover, with this device, permeability measurements have been performed on a cracked specimen. Finally, numerical simulations of massive structures highlight the influence of boundary conditions for restrained shrinkage and the influence of the coupling between creep and damage on the damage pattern. (author)

Nonlinear dynamic analysis of framed structures including soil-structure interaction effects

International Nuclear Information System (INIS)

Mahmood, M.N.; Ahmed, S.Y.

2008-01-01

The role of oil-structure interaction on seismic behavior of reinforced concrete structures is investigated in this paper. A finite element approach has been adopted to model the interaction system that consists of the reinforced concrete plane frame, soil deposit and interface which represents the frictional between foundation of the structure and subsoil. The analysis is based on the elasto-plastic behavior of the frame members (beams and columns) that is defined by the ultimate axial force-bending moment interaction curve, while the cap model is adopted to govern the elasto-plastic behavior of the soil material. Mohr-Coulomb failure law is used to determine the initiation of slippage at the interface, while the separation is assumed to determine the initiation of slippage at the interface, while the separation is assumed to occur when the stresses at the interface becomes tension stresses. New-Mark's Predictor-Corrector algorithm is adopted for nonlinear dynamic analysis. The main aim of present work is to evaluate the sensitivity of structures to different behavior of the soil and interface layer when subjected to an earthquake excitation. Predicted results of the dynamic analysis of the interaction system indicate that the soil-structure interaction problem can have beneficial effects on the structural behavior when different soil models (elastic and elasto-plastic) and interface conditions (perfect bond and permitted slip)are considered. (author)

River flooding due to intense precipitation

International Nuclear Information System (INIS)

Lin, James C.

2014-01-01

River stage can rise and cause site flooding due to local intense precipitation (LIP), dam failures, snow melt in conjunction with precipitation or dam failures, etc. As part of the re-evaluation of the design basis as well as the PRA analysis of other external events, the likelihood and consequence of river flooding leading to the site flooding need to be examined more rigorously. To evaluate the effects of intense precipitation on site structures, the site watershed hydrology and pond storage are calculated. To determine if river flooding can cause damage to risk-significant systems, structures, and components (SSC), water surface elevations are analyzed. Typically, the amount and rate of the input water is determined first. For intense precipitation, the fraction of the rainfall in the watershed drainage area not infiltrated into the ground is collected in the river and contributes to the rise of river water elevation. For design basis analysis, the Probable Maximum Flood (PMF) is evaluated using the Probable Maximum Precipitation (PMP) based on the site topography/configuration. The peak runoff flow rate and water surface elevations resulting from the precipitation induced flooding can then be estimated. The runoff flow hydrograph and peak discharge flows can be developed using the synthetic hydrograph method. The standard step method can then be used to determine the water surface elevations along the river channel. Thus, the flood water from the local intense precipitation storm and excess runoff from the nearby river can be evaluated to calculate the water surface elevations, which can be compared with the station grade floor elevation to determine the effects of site flooding on risk-significant SSCs. The analysis needs to consider any possible diversion flow and the effects of changes to the site configurations. Typically, the analysis is performed based on conservative peak rainfall intensity and the assumptions of failure of the site drainage facilities

Potential fluctuations due to randomly distributed charges at the semiconductor-insulator interface in mis-structures

International Nuclear Information System (INIS)

Yanchev, I; Slavcheva, G.

1993-01-01

A new expression for the Fourier transform of the binary correlation function of the random potential near the semiconductor-insulator interface is derived. The screening from the metal electrode in MIS-structure is taken into account introducing an effective insulator thickness. An essential advantage of this correlation function is the finite dispersion of the random potential Γ 2 to which it leads in distinction with the so far known correlation functions leading to divergent dispersion. The important characteristic of the random potential distribution Γ 2 determining the amplitude of the potential fluctuations is calculated. 7 refs. (orig.)

Effect of graphene on photoluminescence properties of graphene/GeSi quantum dot hybrid structures

International Nuclear Information System (INIS)

Chen, Y. L.; Ma, Y. J.; Wang, W. Q.; Ding, K.; Wu, Q.; Fan, Y. L.; Yang, X. J.; Zhong, Z. Y.; Jiang, Z. M.; Chen, D. D.; Xu, F.

2014-01-01

Graphene has been discovered to have two effects on the photoluminescence (PL) properties of graphene/GeSi quantum dot (QD) hybrid structures, which were formed by covering monolayer graphene sheet on the multilayer ordered GeSi QDs sample surfaces. At the excitation of 488 nm laser line, the hybrid structure had a reduced PL intensity, while at the excitation of 325 nm, it had an enhanced PL intensity. The attenuation in PL intensity can be attributed to the transferring of electrons from the conducting band of GeSi QDs to the graphene sheet. The electron transfer mechanism was confirmed by the time resolved PL measurements. For the PL enhancement, a mechanism called surface-plasmon-polariton (SPP) enhanced absorption mechanism is proposed, in which the excitation of SPP in the graphene is suggested. Due to the resonant excitation of SPP by incident light, the absorption of incident light is much enhanced at the surface region, thus leading to more exciton generation and a PL enhancement in the region. The results may be helpful to provide us a way to improve optical properties of low dimensional surface structures.

Risk Reduction Effects Due to the Start Time Extension of EDGs in OPR-1000

International Nuclear Information System (INIS)

Lim, Ho-Gon; Yang, Joon-Eon; Hwang, Mee-Jeong

2006-01-01

Under the condition that the ECCS rule in Korea will be revised based on the new U.S. 10 CFR 50.46, the risk impact due to the EDG start time extension is analyzed in the present study. This paper is composed of 6 sections. In the section 2, the LOCA break size that cannot be mitigable under the condition of extended EDG start time is obtained from the thermal hydraulic analysis. The section 3 discusses the frequency of the immitigable LOCA and the probability of the LOOP given a LOCA. In the section 4, the effect of the EDG start time extension on its failure probability is discussed with a qualitative manner. Finally, the whole risk change due to the EDG start time extension is calculated in the section 5 with the conclusions given in the section 6

Brain Structural Effects of Psychopharmacological Treatment in Bipolar Disorder

Science.gov (United States)

McDonald, Colm

2015-01-01

Bipolar disorder is associated with subtle neuroanatomical deficits including lateral ventricular enlargement, grey matter deficits incorporating limbic system structures, and distributed white matter pathophysiology. Substantial heterogeneity has been identified by structural neuroimaging studies to date and differential psychotropic medication use is potentially a substantial contributor to this. This selective review of structural neuroimaging and diffusion tensor imaging studies considers evidence that lithium, mood stabilisers, antipsychotic medication and antidepressant medications are associated with neuroanatomical variation. Most studies are negative and suffer from methodological weaknesses in terms of directly assessing medication effects on neuroanatomy, since they commonly comprise posthoc assessments of medication associations with neuroimaging metrics in small heterogenous patient groups. However the studies which report positive findings tend to form a relatively consistent picture whereby lithium and antiepileptic mood stabiliser use is associated with increased regional grey matter volume, especially in limbic structures. These findings are further supported by the more methodologically robust studies which include large numbers of patients or repeated intra-individual scanning in longitudinal designs. Some similar findings of an apparently ameliorative effect of lithium on white matter microstructure are also emerging. There is less support for an effect of antipsychotic or antidepressant medication on brain structure in bipolar disorder, but these studies are further limited by methodological difficulties. In general the literature to date supports a normalising effect of lithium and mood stabilisers on brain structure in bipolar disorder, which is consistent with the neuroprotective characteristics of these medications identified by preclinical studies. PMID:26412064

Effects of Repeated Growing Season Prescribed Fire on the Structure and Composition of Pine–Hardwood Forests in the Southeastern Piedmont, USA

Directory of Open Access Journals (Sweden)

Matthew J. Reilly

2016-12-01

Full Text Available We examined the effects of repeated growing season prescribed fire on the structure and composition of mixed pine–hardwood forests in the southeastern Piedmont region, Georgia, USA. Plots were burned two to four times over an eight-year period with low intensity surface fires during one of four six-week long periods from early April to mid-September. Density of saplings (0.25–11.6 cm diameter at breast height was significantly reduced after one or two fires during the first four-year period. Sapling density declined with additional burning over the next four years, but density of mesic hardwoods including sweetgum (Liquidambar styraciflua and red maple (Acer rubrum remained relatively high (~865 stems ha−1. Repeated burning had little effect on density or basal area of trees (≥11.7 cm dbh and changes in overstory structure were limited to small increases in the quadratic mean diameter of all trees and pines. We found little evidence to suggest differential effects on structure or composition due to timing of burn within the growing season. Although repeated growing season burning alters midstory structure and composition, burning alone is unlikely to result in immediate shifts in overstory composition or structure in mixed pine–hardwood forests of the southeastern Piedmont region.

Low-redshift effects of local structure on the Hubble parameter in presence of a cosmological constant

Energy Technology Data Exchange (ETDEWEB)

Romano, Antonio Enea [University of Crete, Department of Physics and CCTP, Heraklion (Greece); Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia); Vallejo, Sergio Andres [Kyoto University, Yukawa Institute for Theoretical Physics, Kyoto (Japan); Universidad de Antioquia, Instituto de Fisica, Medellin (Colombia)

2016-04-15

In order to estimate the effects of a local structure on the Hubble parameter we calculate the low-redshift expansion for H(z) and (δH)/(H) for an observer at the center of a spherically symmetric matter distribution in the presence of a cosmological constant. We then test the accuracy of the formulas comparing them with fully relativistic non-perturbative numerical calculations for different cases for the density profile. The low-redshift expansion we obtain gives results more precise than perturbation theory since it is based on the use of an exact solution of Einstein's field equations. For larger density contrasts the low-redshift formulas accuracy improves respect to the perturbation theory accuracy because the latter is based on the assumption of a small density contrast, while the former does not rely on such an assumption. The formulas can be used to take into account the effects on the Hubble expansion parameter due to the monopole component of the local structure. If the H(z) observations will show deviations from the ΛCDM prediction compatible with the formulas we have derived, this could be considered an independent evidence of the existence of a local inhomogeneity, and the formulas could be used to determine the characteristics of this local structure. (orig.)

The effects of musical training on structural brain development: a longitudinal study.

Science.gov (United States)

Hyde, Krista L; Lerch, Jason; Norton, Andrea; Forgeard, Marie; Winner, Ellen; Evans, Alan C; Schlaug, Gottfried

2009-07-01

Long-term instrumental music training is an intense, multisensory and motor experience that offers an ideal opportunity to study structural brain plasticity in the developing brain in correlation with behavioral changes induced by training. Here, for the first time, we demonstrate structural brain changes after only 15 months of musical training in early childhood, which were correlated with improvements in musically relevant motor and auditory skills. These findings shed light on brain plasticity, and suggest that structural brain differences in adult experts (whether musicians or experts in other areas) are likely due to training-induced brain plasticity.

Structural and Electrical Analysis of Various MOSFET Designs

OpenAIRE

Pallavi Choudhary; Tarun Kapoor

2015-01-01

Invention of Transistor is the foundation of electronics industry. Metal Oxide Semiconductor Field Effect Transistor (MOSFET) has been the key to the development of nano electronics technology. This paper offers a brief review of some of the most popular MOSFET structure designs. The scaling down of planar bulk MOSFET proposed by the Moore’s Law has been saturated due to short channel effects and DIBL. Due to this alternative approaches has been considered to overcome the problems...

Effects of Vitrectomy on Recurrent Macular Edema due to Branch Retinal Vein Occlusion after Intravitreal Injection of Bevacizumab

Directory of Open Access Journals (Sweden)

Tatsuya Yunoki

2013-01-01

Full Text Available Purpose. To evaluate the effects of pars plana vitrectomy (PPV on recurrent macular edema due to branch retinal vein occlusion (BRVO after intravitreal injections of bevacizumab (IVB. Methods. This retrospective study included 22 eyes of 22 patients who underwent single or multiple IVB injections for macular edema due to BRVO and showed a recurrence of macular edema. All patients then underwent PPV and were followed up for more than 6 months after the surgery with examinations of best corrected visual acuity (BCVA and optical coherence tomography (OCT. OCT parameters were central macular thickness (CMT and average retinal thickness in a 1-mm-diameter circular region at the fovea (MRT. Results. Mean BCVA, CRT, and MRT were significantly improved from the baseline after PPV. Greater improvement of BCVA, CRT, and MRT was obtained after 1 month of IVB than after 6 months of PPV. No eyes showed worsening of macular edema after the surgery. Conclusion. PPV improved BCVA and recurrent macular edema due to BRVO, but PPV that was less effective than IVB had been in the same patients. PPV may be one of the treatment options for recurrent macular edema due to BRVO after IVB.

Climate Change Impacts on Flood risk in Urban Areas due to Combined Effects of Extreme Precipitation and Sea Surges

DEFF Research Database (Denmark)

Larsen, A. N.; Mikkelsen, Peter Steen; Arnbjerg-Nielsen, Karsten

Climate change will impact the hydrological cycle greatly and lead to increases in flood hazards due to both pluvial and fluvial floods as well as sea surges in many regions. The impacts of the individual effects are analysed for a catchment in Greater Copenhagen. Based on both the present...... surges. Presently the most important hazard is due to extreme precipitation. However, due to climate change impacts the future most important hazard is due to sea surges. The increase in probability of floods is substantial over a 70 year horizon and actions must be taken to decrease either the hazards...

Transient electromagnetic and dynamic structural analyses of a blanket structure with coupling effects

Energy Technology Data Exchange (ETDEWEB)

Koganezawa, K. [Mitsubishi Atomic Power Industries, Inc., Yokohama (Japan); Kushiyama, M. [Mitsubishi Atomic Power Industries, Inc., Yokohama (Japan); Niikura, S. [Mitsubishi Atomic Power Industries, Inc., Yokohama (Japan); Kudough, F. [Mitsubishi Atomic Power Industries, Inc., Yokohama (Japan); Onozuka, M. [Mitsubishi Heavy Industries Ltd., Yokohama (Japan); Koizumi, K. [Japan Atomic Energy Research Inst., Ibaraki (Japan)

1995-12-31

Transient electromagnetic and dynamic structural analyses of a blanket structure in the fusion experimental reactor (FER) under a plasma disruption event and a vertical displacement event (VDE) have been performed to investigate the dynamic structural characteristics and the feasibility of the structure. Coupling effects between eddy currents and dynamic deflections have also been taken into account in these analyses. In this study, the inboard blanket was employed because of our computer memory limitation. A 1/192 segment model of a full torus was analyzed using the analytical code, EDDYCUFF. In the plasma disruption event, the maximum magnetic pressure caused by eddy currents and poloidal fields was 1.2MPa. The maximum stress intensity by this magnetic pressure was 114MPa. In the VDE, the maximum magnetic pressure was 2.4MPa and the maximum stress intensity was 253MPa. This stress was somewhat beyond the allowable stress limit. Therefore, the blanket structure and support design should be reviewed to reduce the stress to a suitable value. In summary, the dynamic structural characteristics and design issues of the blanket structure have been identified. (orig.).

Effect of single vacancy on the structural, electronic structure and magnetic properties of monolayer graphyne by first-principles

Energy Technology Data Exchange (ETDEWEB)

Yun, Jiangni, E-mail: niniyun@nwu.edu.cn; Zhang, Yanni; Xu, Manzhang; Wang, Keyun; Zhang, Zhiyong

2016-10-01

The effect of single vacancy on the structural, electronic and magnetic properties of monolayer graphyne is investigated by the first-principles calculations. The calculated results reveal that single vacancy can result in the spin polarization in monolayer graphyne and the spin polarization is sensitive to local geometric structure of the vacancy. In the case of monolayer graphyne with one single vacancy at the sp{sup 2} hybridized C site, the vacancy introduces rather weakly spin-polarized, flat bands in the band gap. Due to the localization nature of the defect-induced bands, the magnetic moment is mainly localized at the vacancy site. As for the monolayer graphyne with one single vacancy at the sp hybridized C site, one defect-induced state which is highly split appears in the band gap. The spin-up band of the defect-induced state is highly dispersive and shows considerable delocalization, suggesting that the magnetic moment is dispersed around the vacancy site. The above magnetization in monolayer graphyne with one single vacancy is possibly explained in terms of the valence-bond theory. - Graphical abstract: Calculated band structure of the monolayer graphyne without (a) and with one single vacancy at Vb site (b) and at Vr site(c), respectively. Blue and red lines represent the spin-up and spin-down bands, respectively. For the sake of clarity, the band structure near the Fermi energy is also presented on the right panel. The Fermi level is set to zero on the energy scale. - Highlights: • A Jahn-Teller distortion occurs in monolayer graphyne with single vacancy. • The spin polarization is sensitive to local geometric structure of the vacancy. • Vacancy lying at sp{sup 2} hybridized C site introduces weakly spin-polarized defect bands. • A strong spin splitting occurs when the vacancy lies at sp hybridized C site. • The magnetization is explained in terms of the valence-bond theory.

Investigation of neutron radiation effects in structural materials for CTR use

International Nuclear Information System (INIS)

Wiffen, F.W.

1975-01-01

Neutron irradiation of structural materials in the high-flux region of a Controlled Thermonuclear Reactor (CTR), especially in the first wall of the reactor, will result in swelling due to cavity formation and loss of ductility through both lattice hardening and the effect of transmutation-produced helium on the fracture mode. The intensity and relative importance of the effects will be a strong function of the material and reactor operating conditions. A consideration of the effects of the 14 MeV D-T fusion neutrons, based on calculated damage response, on the sparse available data from high-energy neutron irradiation, and on an intuitive understanding of past radiation effects experimentation, suggests that although the 14 MeV neutrons will produce damage at a higher rate than lower-energy neutrons, there is no basis for anticipating different forms of damage. Irradiation experiments designed to evaluate materials for CTR service must be conducted in a number of facilities. Used in a well-coordinated evaluation program, the combined results from all available irradiation facilities will lead to an understanding of the radiation effects that will occur in CTRs. The experimental program will involve three distinct phases: (a) correlation experiments, (b) screening studies, and (c) qualification and design data generation. Each of these phases will evaluate a number of physical and mechanical properties. The end result of this program will be the qualification of a few materials for CTR use

Cost-Effective Fabrication of Inner-Porous Micro/Nano Carbon Structures.

Science.gov (United States)

Jiang, Shulan; Shi, Tielin; Tang, Zirong; Xi, Shuang

2018-03-01

This paper reports the fabrication of a new micro/nano carbon architecture array which owns the characteristics of inner-porous, desired conductivity and large effective surface area. The micro/nano inner-porous carbon structures were fabricated for the first time, with ordinary and cost-effective processes, including photolithography, oxygen plasma etching and pyrolysis. Firstly, micro/nano hierarchical photoresist structures array was generated through photolithography and oxygen plasma etching processes. By introducing a critical thin-film spin-coating step, and followed with carefully pyrolyzing process, the micro/nano photoresist structures were converted into innerporous carbon architectures with good electric connection which connected the carbon structures array together. Probably the inner-porous property can be attributed to the shrinkage difference between positive thin film and negative photoresist structures during pyrolyzing process. It is demonstrated that the simple method is effective to fabricate inner-porous carbon structures with good electric connection and the carbon structures can be used as electrochemical electrodes directly and without the addition of other pyrolysis or film coating processes. The electrochemical property of the carbon structures has been explored by cyclic voltammetric measurement. Compared with solid carbon microstructures array, the cyclic voltammetry curve of inner-porous carbon structures shows greatly enhanced current and improved charge-storage capability, indicating great potential in micro energy storage devices and bio-devices.