Parental separation and adult psychological distress: an investigation of material and relational mechanisms.

Science.gov (United States)

Lacey, Rebecca E; Bartley, Mel; Pikhart, Hynek; Stafford, Mai; Cable, Noriko

2014-03-23

An association between parental separation or divorce occurring in childhood and increased psychological distress in adulthood is well established. However relatively little is known about why this association exists and how the mechanisms might differ for men and women. We investigate why this association exists, focussing on material and relational mechanisms and in particular on the way in which these link across the life course. This study used the 1970 British Cohort Study (n=10,714) to investigate material (through adolescent and adult material disadvantage, and educational attainment) and relational (through parent-child relationship quality and adult partnership status) pathways between parental separation (0-16 years) and psychological distress (30 years). Psychological distress was measured using Rutter's Malaise Inventory. The inter-linkages between these two broad mechanisms across the life course were also investigated. Missing data were multiply imputed by chained equations. Path analysis was used to explicitly model prospectively-collected measures across the life course, therefore methodologically extending previous work. Material and relational pathways partially explained the association between parental separation in childhood and adult psychological distress (indirect effect=33.3% men; 60.0% women). The mechanisms were different for men and women, for instance adult partnership status was found to be more important for men. Material and relational factors were found to interlink across the life course. Mechanisms acting through educational attainment were found to be particularly important. This study begins to disentangle the mechanisms between parental separation in childhood and adult psychological distress. Interventions which aim to support children through education, in particular, are likely to be particularly beneficial for later psychological health.

How do we have to change quantum mechanics in order to describe separated systems

International Nuclear Information System (INIS)

Aerts, D.

1984-01-01

Since it has been shown recently that quantum mechanics can not describe separated physical systems the author reanalyses the reasoning of Einstein-Podolsky-Rosen, and finds that the most straight forward conclusion of this paradox is not correct. He indicates the missing elements of reality in the quantum mechanical description of separated physical systems. He shows that Bell inequalities are satisfied if the two physical systems are separated, whether the systems are quantum systems or classical systems is of no matter. An example of a classical macroscopical situation where Bell inequalities are violated is given. (Auth.)

Properties influencing cracking and separation of palm nuts in a mechanical cracker cum separator

Directory of Open Access Journals (Sweden)

JOSHUA OLANREWAJU OLAOYE

2018-01-01

Full Text Available Experimental studies of some properties influencing cracking and separation of palm kernel from the shell was conducted in a palm kernel dual processing machine. A mechanical cracking cum separating machine was developed for the study. The cracking unit consists of feed hopper, impeller shaft, cracking drum and impeller blade. The nut falls by gravity through the hopper channel into the cracking drum where the cracking process takes place through the help of impeller blades that flip the palm nut against the walls of cylindrical cracking drum. The mass of cracked nut flows through the separating unit that separates the kernel from the shell. The separation is induced by high current of air mass generated by an axial fan. A dura palm variety was selected and a total sample of eighteen thousand (18000 palm nuts were obtained and divided into two groups (feed rates, A and B, of eight thousand and ten thousand palm nuts respectively. Sample groups A and B were further divided into five sub – groups of four hundred (400 and five hundred (500 palm kernel nuts. Each sub group (feed rate was replicated four times at different shaft speeds (600, 900, 1200, 1500 and 1800 rpm. Results showed that cracking efficiencies increased with respect to speed. Un-cracked nuts percentage ranged from 1.3 to 5.3% at 7.1% moisture content, and 1.6 to 4.5% for 400 and 500 feed rates, respectively. Cracking time for both feed rates decreased with shaft speed. Throughput capacity of 11.49 kg/h was observed to be the lowest at 600 rpm and moisture content of 7.1% for both 400 feed rates and the highest throughput capacity of 37.16 kg/h was recorded at 1800 rpm at moisture contents of 9.3% and 16.1%. The results of this study shows that moisture content, engine speed and feed rate are significant parameters that influence cracking of nuts and separation of palm kernel from the shell.

Mechanical separation of chiral dipoles by chiral light

International Nuclear Information System (INIS)

Canaguier-Durand, Antoine; Hutchison, James A; Genet, Cyriaque; Ebbesen, Thomas W

2013-01-01

We calculate optical forces and torques exerted on a chiral dipole by chiral light fields and reveal genuine chiral forces in combining the chiral contents of both light field and dipolar matter. Here, the optical chirality is characterized in a general way through the definition of optical chirality density and chirality flow. We show, in particular, that both terms have mechanical effects associated, respectively, with reactive and dissipative components of the chiral forces. Remarkably, these chiral force components are directly related to standard observables: optical rotation for the reactive component and circular dichroism for the dissipative one. As a consequence, the resulting forces and torques are dependent on the enantiomeric form of the chiral dipole. This suggests promising strategies for using chiral light forces to mechanically separate chiral objects according to their enantiomeric form. (paper)

Phase separation of cesium from lead borosilicate glass by heat treatment under a reducing atmosphere

Energy Technology Data Exchange (ETDEWEB)

Xu, Zhanglian; Okada, Takashi, E-mail: t-okada@u-fukui.ac.jp; Nishimura, Fumihiro; Yonezawa, Susumu

2016-11-05

Highlights: • Cesium was phase separated from lead borosilicate glass under a reductive atmosphere. • The phase separation occurred on the glass surface that was in contact with the gas. • The leachability of cesium was enhanced by the phase separation. • The degree of such enhancement varied depending on the heat treatment conditions. - Abstract: A phase-separation technique for removing sodium from glass using a heat-treatment method under a reducing atmosphere was previously developed for sodium recovery from waste glass. In this study, this technique was applied to cesium-containing lead borosilicate glass to concentrate the cesium in phase-separated sodium-rich materials for efficient cesium extraction. The theoretical phase-separation temperature of the sodium-rich phase was simulated by thermodynamic equilibrium calculations and was predicted to occur below 700 °C for lead borosilicate glass. Experimentally, a simulated lead borosilicate glass was melted at 1000 °C and subsequently annealed below 700 °C under a CO-containing reducing atmosphere. The phase separation of cesium was found to occur with sodium enrichment on the glass surface that was in contact with the gas phase, promoting cesium extraction from the treated glass using water. The cesium extraction efficiency was affected by the surface area of the treated glass that was in contact with water, and under the examined conditions, the cesium extraction efficiency was up to 66%. Phase separation using reductive heat treatment, combined with a water leaching technique, is suggested to be effective for extracting cesium incorporated in borosilicate glass waste.

Neural mechanisms underlying human consensus decision-making.

Science.gov (United States)

Suzuki, Shinsuke; Adachi, Ryo; Dunne, Simon; Bossaerts, Peter; O'Doherty, John P

2015-04-22

Consensus building in a group is a hallmark of animal societies, yet little is known about its underlying computational and neural mechanisms. Here, we applied a computational framework to behavioral and fMRI data from human participants performing a consensus decision-making task with up to five other participants. We found that participants reached consensus decisions through integrating their own preferences with information about the majority group members' prior choices, as well as inferences about how much each option was stuck to by the other people. These distinct decision variables were separately encoded in distinct brain areas-the ventromedial prefrontal cortex, posterior superior temporal sulcus/temporoparietal junction, and intraparietal sulcus-and were integrated in the dorsal anterior cingulate cortex. Our findings provide support for a theoretical account in which collective decisions are made through integrating multiple types of inference about oneself, others, and environments, processed in distinct brain modules. Copyright © 2015 Elsevier Inc. All rights reserved.

Opto-mechanical design of the MTG FCI spectral separation assembly

Science.gov (United States)

Riguet, François; Brousse, Emmanuel; Carel, Jean-Louis; Cottenye, Justine; Harmann, David; Joncour, Marc; Makhlouf, Houssine; Mouricaud, Daniel; Oussalah, Meihdi; Rodolfo, Jacques

2015-09-01

The Spectral Separation Assembly is a key component of the Flexible Combined Imager, an instrument that will be on-board Meteosat Third Generation. It splits the input beam coming from the telescope into five spectral groups, for a total of 16 channels, from 0.4 to 13.3 μm. It comprises a set of four dichroics separators followed by four collimating optics for the infrared spectral groups, which feed the cold imaging optics. The visible spectral group is directly imaged on a detector. This paper presents the optical design of the assembly, the mechanical mounting of the optical components, and the coatings developed for the dichroics, mirrors and lenses.

The Preceding Voltage Pulse and Separation Welding Mechanism of Electrical Contacts

DEFF Research Database (Denmark)

Yang, Xiao Cheng; Huang, Jiang; Li, Zhen Biao

2016-01-01

In order to obtain a better understanding of the welding mechanism in contact separation, electrical endurance tests were conducted with AgSnO2 and AgNi contacts on a simulation test device. Waveforms of contact displacement, contact voltage, and current were recorded with LabVIEW during the tests......, and changes in a contact gap and heights of pips with increases in operation cycles were observed through charge-coupled device cameras. The resultant test results show that welding in separation is accompanied with a preceding voltage pulse which represents arc rather than contact bounce arc....

Bio-inspired particle separator design based on the food retention mechanism by suspension-feeding fish

International Nuclear Information System (INIS)

Hung, Tien-Chieh; Piedrahita, Raul H; Cheer, Angela

2012-01-01

A new particle separator is designed using a crossflow filtration mechanism inspired by suspension-feeding fish in this study. To construct the model of the bio-inspired particle separator, computational fluid dynamics techniques are used, and parameters related to separator shape, fluid flow and particle properties that might affect the performance in removing particles from the flow, are varied and tested. The goal is to induce a flow rotation which enhances the separation of particles from the flow, reduce the particle-laden flow that exits via a collection zone at the lower/posterior end of the separator, while at the same time increase the concentration of particles in that flow. Based on preliminary particle removal efficiency tests, an exiting flow through the collection zone of about 8% of the influent flow rate is selected for all the performance tests of the separator including trials with particles carried by air flow instead of water. Under this condition, the simulation results yield similar particle removal efficiencies in water and air but with different particle properties. Particle removal efficiencies (percentage of influent particles that exit through the collection zone) were determined for particles ranging in size from 1 to 1500 µm with a density between 1000 and 1150 kg m −3 in water and 2 and 19 mm and 68 and 2150 kg m −3 in air. As an example, removal efficiencies are 66% and 64% for 707 µm diameter particles with a density of 1040 kg m −3 in water and for 2 mm particles with a density of 68 kg m −3 in air, respectively. No significant performance difference is found by geometrically scaling the inlet diameter of the separator up or down in the range from 2.5 to 10 cm. (paper)

Sludge Water Characteristics Under Different Separation Methods from a Membrane Bioreactor

KAUST Repository

Wei, Chunhai

2013-11-22

The concept of sludge water was proposed to integrate the relative terminologies and its characteristics under different separation methods from a membrane bioreactor (MBR) were investigated in this study. Based on chemical oxygen demand (COD) and three-dimensional fluorescence excitation-emission matrix (F-EEM), and compared with the control (gravitational sedimentation), some suspended particulate organics or biopolymer clusters (mainly proteins) were released from sludge flocs into the supernatant after centrifugation under low to middle centrifugal forces (10-4000 g) and then aggregated into a pellet under high centrifugal forces (10000-20000 g). Filtration (1.2 μm glass fiber filter) produced sludge water with a lower biopolymers concentration than the control (gravitational sedimentation followed by filtration) due to cake layer formation during filtration. As for centrifugation followed by filtration, low to middle centrifugal forces did not significantly affect sludge water characteristics but high centrifugal forces reduced the concentrations of some proteins in sludge water from advanced analytical protocols including F-EEM and liquid chromatography with on-line organic carbon detection (LC-OCD), demonstrating a low to middle centrifugal force suitable for MBR sludge water separation. From LC-OCD, the main fractions of sludge water were humic substances and building blocks, low molecular weight neutrals and biopolymers (mainly proteins rather than polysaccharides). Supplemental materials are available for this article. Go to the publisher\\'s online edition of Separation Science and Technology to view the supplemental file. © 2013 Copyright Taylor and Francis Group, LLC.

Sludge Water Characteristics Under Different Separation Methods from a Membrane Bioreactor

KAUST Repository

Wei, Chunhai; Amy, Gary L.

2013-01-01

The concept of sludge water was proposed to integrate the relative terminologies and its characteristics under different separation methods from a membrane bioreactor (MBR) were investigated in this study. Based on chemical oxygen demand (COD) and three-dimensional fluorescence excitation-emission matrix (F-EEM), and compared with the control (gravitational sedimentation), some suspended particulate organics or biopolymer clusters (mainly proteins) were released from sludge flocs into the supernatant after centrifugation under low to middle centrifugal forces (10-4000 g) and then aggregated into a pellet under high centrifugal forces (10000-20000 g). Filtration (1.2 μm glass fiber filter) produced sludge water with a lower biopolymers concentration than the control (gravitational sedimentation followed by filtration) due to cake layer formation during filtration. As for centrifugation followed by filtration, low to middle centrifugal forces did not significantly affect sludge water characteristics but high centrifugal forces reduced the concentrations of some proteins in sludge water from advanced analytical protocols including F-EEM and liquid chromatography with on-line organic carbon detection (LC-OCD), demonstrating a low to middle centrifugal force suitable for MBR sludge water separation. From LC-OCD, the main fractions of sludge water were humic substances and building blocks, low molecular weight neutrals and biopolymers (mainly proteins rather than polysaccharides). Supplemental materials are available for this article. Go to the publisher's online edition of Separation Science and Technology to view the supplemental file. © 2013 Copyright Taylor and Francis Group, LLC.

Separating grain boundary migration mechanisms in molecular dynamics simulations

International Nuclear Information System (INIS)

Ulomek, Felix; Mohles, Volker

2016-01-01

In molecular dynamics (MD) simulations of grain boundary (GB) migration it is quite common to find a temperature dependence of GB mobility that deviates strongly from an Arrhenius-type dependence. This usually indicates that more than one mechanism is actually active. With the goal to separate different GB migration mechanisms we investigate a Σ7 <111> 38.2° GB by MD using an EAM potential for aluminium. To drive the GB with a well-known and adjustable force, the energy conserving orientational driving force (ECO DF) is used that had been introduced recently. The magnitude of the DF and the temperature are varied. This yielded a high and a low temperature range for the GB velocity, with a transition temperature that depends on the magnitude of the DF. A method is introduced which allows both a visual and a statistical characterization of GB motion on a per atom basis. These analyses reveal that two mechanisms are active in this GB, a shuffling mechanism and its initiation. These mechanisms operate in a sequential, coupled manner. Based on this, a simple model is introduced that describes all simulated GB velocities (and hence the mobility) very well, including the transition between the dominating mechanisms.

Simulation of fatigue damage in ferroelectric polycrystals under mechanical/electrical loading

Science.gov (United States)

Kozinov, S.; Kuna, M.

2018-07-01

The reliability of smart-structures made of ferroelectric ceramics is essentially reduced by the formation of cracks under the action of external electrical and/or mechanical loading. In the current research a numerical model for low-cycle fatigue in ferroelectric mesostructures is proposed. In the finite element simulations a combination of two user element routines is utilized. The first one is used to model a micromechanical ferroelectric domain switching behavior inside the grains. The second one is used to simulate fatigue damage of grain boundaries by a cohesive zone model (EMCCZM) based on an electromechanical cyclic traction-separation law (TSL). For numerical simulations a scanning electron microscope image of the ceramic's grain structure was digitalized and meshed. The response of this mesostructure to cyclic electrical or mechanical loading is systematically analyzed. As a result of the simulations, the distribution of electric potential, field, displacement and polarization as well as mechanical stresses and deformations inside the grains are obtained. At the grain boundaries, the formation and evolution of damage are analyzed until final failure and induced degradation of electric permittivity. It is found that the proposed model correctly mimics polycrystalline behavior during poling processes and progressive damage under cyclic electromechanical loading. To the authors' knowledge, it is the first model and numerical analysis of ferroelectric polycrystals taking into account both domain reorientation and cohesive modeling of intergranular fracture. It can help to understand failure mechanisms taking place in ferroelectrics during fatigue processes.

Boundary-Layer Separation Control under Low-Pressure Turbine Airfoil Conditions using Glow-Discharge Plasma Actuators

Science.gov (United States)

Hultgren, Lennart S.; Ashpis, David E.

2003-01-01

Modem low-pressure turbines, in general, utilize highly loaded airfoils in an effort to improve efficiency and to lower the number of airfoils needed. Typically, the airfoil boundary layers are turbulent and fully attached at takeoff conditions, whereas a substantial fraction of the boundary layers on the airfoils may be transitional at cruise conditions due to the change of density with altitude. The strong adverse pressure gradients on the suction side of these airfoils can lead to boundary-layer separation at the latter low Reynolds number conditions. Large separation bubbles, particularly those which fail to reattach, cause a significant degradation of engine efficiency. A component efficiency drop of the order 2% may occur between takeoff and cruise conditions for large commercial transport engines and could be as large as 7% for smaller engines at higher altitude. An efficient means of of separation elimination/reduction is, therefore, crucial to improved turbine design. Because the large change in the Reynolds number from takeoff to cruise leads to a distinct change in the airfoil flow physics, a separation control strategy intended for cruise conditions will need to be carefully constructed so as to incur minimum impact/penalty at takeoff. A complicating factor, but also a potential advantage in the quest for an efficient strategy, is the intricate interplay between separation and transition for the situation at hand. Volino gives a comprehensive discussion of several recent studies on transition and separation under low-pressure-turbine conditions, among them one in the present facility. Transition may begin before or after separation, depending on the Reynolds number and other flow conditions. If the transition occurs early in the boundary layer then separation may be reduced or completely eliminated. Transition in the shear layer of a separation bubble can lead to rapid reattachment. This suggests using control mechanisms to trigger and enhance early

Strain distribution and failure mode of polymer separators for Li-ion batteries under biaxial loading

Science.gov (United States)

Kalnaus, Sergiy; Kumar, Abhishek; Wang, Yanli; Li, Jianlin; Simunovic, Srdjan; Turner, John A.; Gorney, Phillip

2018-02-01

Deformation of polymer separators for Li-ion batteries has been studied under biaxial tension by using a dome test setup. This deformation mode provides characterization of separator strength under more complex loading conditions, closer representing deformation of an electric vehicle battery during crash event, compared to uniaxial tension or compression. Two polymer separators, Celgard 2325 and Celgard 2075 were investigated by deformation with spheres of three different diameters. Strains in separators were measured in situ by using Digital Image Correlation (DIC) technique. The results show consistent rupture of separators along the machine direction coinciding with areas of high strain accumulation. The critical first principal strain for failure was independent of the sphere diameter and was determined to be approximately 34% and 43% for Celgard 2325 and Celgard 2075 respectively. These values can be taken as a criterion for internal short circuit in a battery following an out-of-plane impact. A Finite Element (FE) model was built with the anisotropic description of separator behavior, derived from tensile tests in orthogonal directions. The results of simulations predicted the response of separator rather well when compared to experimental results for various sizes of rigid sphere.

Fast Mechanically Driven Daughter Cell Separation Is Widespread in Actinobacteria.

Science.gov (United States)

Zhou, Xiaoxue; Halladin, David K; Theriot, Julie A

2016-08-30

Dividing cells of the coccoid Gram-positive bacterium Staphylococcus aureus undergo extremely rapid (millisecond) daughter cell separation (DCS) driven by mechanical crack propagation, a strategy that is very distinct from the gradual, enzymatically driven cell wall remodeling process that has been well described in several rod-shaped model bacteria. To determine if other bacteria, especially those in the same phylum (Firmicutes) or with similar coccoid shapes as S. aureus, might use a similar mechanically driven strategy for DCS, we used high-resolution video microscopy to examine cytokinesis in a phylogenetically wide range of species with various cell shapes and sizes. We found that fast mechanically driven DCS is rather rare in the Firmicutes (low G+C Gram positives), observed only in Staphylococcus and its closest coccoid relatives in the Macrococcus genus, and we did not observe this division strategy among the Gram-negative Proteobacteria In contrast, several members of the high-G+C Gram-positive phylum Actinobacteria (Micrococcus luteus, Brachybacterium faecium, Corynebacterium glutamicum, and Mycobacterium smegmatis) with diverse shapes ranging from coccoid to rod all undergo fast mechanical DCS during cell division. Most intriguingly, similar fast mechanical DCS was also observed during the sporulation of the actinobacterium Streptomyces venezuelae Much of our knowledge on bacterial cytokinesis comes from studying rod-shaped model organisms such as Escherichia coli and Bacillus subtilis Less is known about variations in this process among different bacterial species. While cell division in many bacteria has been characterized to some extent genetically or biochemically, few species have been examined using video microscopy to uncover the kinetics of cytokinesis and daughter cell separation (DCS). In this work, we found that fast (millisecond) DCS is exhibited by species in two independent clades of Gram-positive bacteria and is particularly prevalent

Coarsening and pattern formation during true morphological phase separation in unstable thin films under gravity

Science.gov (United States)

Kumar, Avanish; Narayanam, Chaitanya; Khanna, Rajesh; Puri, Sanjay

2017-12-01

We address in detail the problem of true morphological phase separation (MPS) in three-dimensional or (2 +1 )-dimensional unstable thin liquid films (>100 nm) under the influence of gravity. The free-energy functionals of these films are asymmetric and show two points of common tangency, which facilitates the formation of two equilibrium phases. Three distinct patterns formed by relative preponderance of these phases are clearly identified in "true MPS". Asymmetricity induces two different pathways of pattern formation, viz., defect and direct pathway for true MPS. The pattern formation and phase-ordering dynamics have been studied using statistical measures such as structure factor, correlation function, and growth laws. In the late stage of coarsening, the system reaches into a scaling regime for both pathways, and the characteristic domain size follows the Lifshitz-Slyozov growth law [L (t ) ˜t1 /3] . However, for the defect pathway, there is a crossover of domain growth behavior from L (t ) ˜t1 /4→t1 /3 in the dynamical scaling regime. We also underline the analogies and differences behind the mechanisms of MPS and true MPS in thin liquid films and generic spinodal phase separation in binary mixtures.

Experimental Investigation of Separated and Transitional Boundary Layers Under Low-Pressure Turbine Airfoil Conditions

Science.gov (United States)

Hultgren, Lennart S.; Volino, Ralph J.

2002-01-01

Modern low-pressure turbine airfoils are subject to increasingly stronger pressure gradients as designers impose higher loading in an effort to improve efficiency and to reduce part count. The adverse pressure gradients on the suction side of these airfoils can lead to boundary-layer separation, particularly under cruise conditions. Separation bubbles, notably those which fail to reattach, can result in a significant degradation of engine efficiency. Accurate prediction of separation and reattachment is hence crucial to improved turbine design. This requires an improved understanding of the transition flow physics. Transition may begin before or after separation, depending on the Reynolds number and other flow conditions, has a strong influence on subsequent reattachment, and may even eliminate separation. Further complicating the problem are the high free-stream turbulence levels in a real engine environment, the strong pressure gradients along the airfoils, the curvature of the airfoils, and the unsteadiness associated with wake passing from upstream stages. Because of the complicated flow situation, transition in these devices can take many paths that can coexist, vary in importance, and possibly also interact, at different locations and instances in time. The present work was carried out in an attempt to systematically sort out some of these issues. Detailed velocity measurements were made along a flat plate subject to the same nominal dimensionless pressure gradient as the suction side of a modern low-pressure turbine airfoil ('Pak-B'). The Reynolds number based on wetted plate length and nominal exit velocity, Re, was varied from 50;000 to 300; 000, covering cruise to takeoff conditions. Low, 0.2%, and high, 7%, inlet free-stream turbulence intensities were set using passive grids. These turbulence levels correspond to about 0.2% and 2.5% turbulence intensity in the test section when normalized with the exit velocity. The Reynolds number and free

Energy and exergy performance of residential heating systems with separate mechanical ventilation

International Nuclear Information System (INIS)

Zmeureanu, Radu; Yu Wu, Xin

2007-01-01

The paper brings new evidence on the impact of separate mechanical ventilation system on the annual energy and exergy performance of several design alternatives of residential heating systems, when they are designed for a house in Montreal. Mathematical models of residential heating, ventilation and domestic hot water (HVAC-DHW) systems, which are needed for this purpose, are developed and furthermore implemented in the Engineering Equation Solver (EES) environment. The Coefficient of Performance and the exergy efficiency are estimated as well as the entropy generation and exergy destruction of the overall system. The equivalent greenhouse gas emissions due to the on-site and off-site use of primary energy sources are also estimated. The addition of a mechanical ventilation system with heat recovery to any HVAC-DHW system discussed in the paper increases the energy efficiency; however, it decreases the exergy efficiency, which indicates a potential long-term damaging impact on the natural environment. Therefore, the use of a separate mechanical ventilation system in a house should be considered with caution, and recommended only when other means for controlling the indoor air quality cannot be applied

Surface Damage Mechanism of Monocrystalline Si Under Mechanical Loading

Science.gov (United States)

Zhao, Qingliang; Zhang, Quanli; To, Suet; Guo, Bing

2017-03-01

Single-point diamond scratching and nanoindentation on monocrystalline silicon wafer were performed to investigate the surface damage mechanism of Si under the contact loading. The results showed that three typical stages of material removal appeared during dynamic scratching, and a chemical reaction of Si with the diamond indenter and oxygen occurred under the high temperature. In addition, the Raman spectra of the various points in the scratching groove indicated that the Si-I to β-Sn structure (Si-II) and the following β-Sn structure (Si-II) to amorphous Si transformation appeared under the rapid loading/unloading condition of the diamond grit, and the volume change induced by the phase transformation resulted in a critical depth (ductile-brittle transition) of cut (˜60 nm ± 15 nm) much lower than the theoretical calculated results (˜387 nm). Moreover, it also led to abnormal load-displacement curves in the nanoindentation tests, resulting in the appearance of elbow and pop-out effects (˜270 nm at 20 s, 50 mN), which were highly dependent on the loading/unloading conditions. In summary, phase transformation of Si promoted surface deformation and fracture under both static and dynamic mechanical loading.

Mechanical properties of cork under contact stresses

International Nuclear Information System (INIS)

Parralejo, A. D.; Guiberteau, F.; Fortes, M. A.; Rosa, M. E.

2001-01-01

In this work our interest is focussed on the mechanical behaviour of natural cork under contact stresses. Many of the applications of this curious material are related with its mechanical response under such a stress field, however this topic has not been still sufficiently considered in the scientific literature. For this purpose, we proposed the use of Hertzian indentation tests. By using this mythology we have investigated the cork structure influence on the corresponding mechanical properties. Our results reveal a clear mechanical anisotropy effect. Moreover, the elastic modulus corresponding to specific directions have been estimated. Several are the main advantages of this specific test mythology versus traditional uniaxial compression tests, specially simplicity and local character. (Author) 9 refs

Doesn't it the quantum mechanics separable?; Es no separable la mecanica cuantica?

Energy Technology Data Exchange (ETDEWEB)

Patino Jaidar, Erick Leonardo [Universidad Nacional Autonoma de Mexico, Mexico, D. F. (Mexico)

2001-04-01

Since its beginning, quantum mechanics has been proposed as a non-separable theory, however, this has been a controversial issue. The arguments with or against the non-local character of the quantum theory has always been closely related to its foundations. Nowadays the general opinions is that non-local effects had been verified and the dead of realism as a philosophical point of view is unavoidable. Nevertheless, the discussion stills open, since the performed experiments rely on very strong and unverified experimental hypothesis. Actually there are realistic and local models which reproduce the experimental results. The main goal of this paper is to expose some of the critics which show that realism has not been rejected, but in fact there are alternative realistic theories which allow deep understanding of the quantum behavior. [Spanish] Desde sus inicios, la mecanica cuantica se ha postulado como una teoria no separable, sin embargo este ha sido siempre un punto generador de gran polemica. Los argumentos a favor o en contra del caracter no local de la teoria cuantica han estado siempre vinculados de manera estrecha con sus fundamentos. La tendencia generalizada a la fecha es pensar que los efectos no separables han sido verificados y que la muerte del realismo como vision filosofica es inevitable. Aun asi, la discusion no ha sido cerrada, puesto que los experimentos realizados se apoyan en hipotesis experimentales muy fuertes no verificadas, lo cual da buenas razones para dudar de ellos. De hecho existen modelos realistas y locales que reproducen los resultados de los experimentos realizados. El principal objetivo de este articulo es exponer algunas de las criticas que demuestran que el realismo no ha sido descartado y que, muy por el contrario, existen teorias realistas alternativas que permiten un entendimiento mucho mas amplio de los fenomenos cuanticos.

Fast Mechanically Driven Daughter Cell Separation Is Widespread in Actinobacteria

Directory of Open Access Journals (Sweden)

Xiaoxue Zhou

2016-08-01

Full Text Available Dividing cells of the coccoid Gram-positive bacterium Staphylococcus aureus undergo extremely rapid (millisecond daughter cell separation (DCS driven by mechanical crack propagation, a strategy that is very distinct from the gradual, enzymatically driven cell wall remodeling process that has been well described in several rod-shaped model bacteria. To determine if other bacteria, especially those in the same phylum (Firmicutes or with similar coccoid shapes as S. aureus, might use a similar mechanically driven strategy for DCS, we used high-resolution video microscopy to examine cytokinesis in a phylogenetically wide range of species with various cell shapes and sizes. We found that fast mechanically driven DCS is rather rare in the Firmicutes (low G+C Gram positives, observed only in Staphylococcus and its closest coccoid relatives in the Macrococcus genus, and we did not observe this division strategy among the Gram-negative Proteobacteria. In contrast, several members of the high-G+C Gram-positive phylum Actinobacteria (Micrococcus luteus, Brachybacterium faecium, Corynebacterium glutamicum, and Mycobacterium smegmatis with diverse shapes ranging from coccoid to rod all undergo fast mechanical DCS during cell division. Most intriguingly, similar fast mechanical DCS was also observed during the sporulation of the actinobacterium Streptomyces venezuelae.

Steady-state configuration and tension calculations of marine cables under complex currents via separated particle swarm optimization

Science.gov (United States)

Xu, Xue-song

2014-12-01

Under complex currents, the motion governing equations of marine cables are complex and nonlinear, and the calculations of cable configuration and tension become difficult compared with those under the uniform or simple currents. To obtain the numerical results, the usual Newton-Raphson iteration is often adopted, but its stability depends on the initial guessed solution to the governing equations. To improve the stability of numerical calculation, this paper proposed separated the particle swarm optimization, in which the variables are separated into several groups, and the dimension of search space is reduced to facilitate the particle swarm optimization. Via the separated particle swarm optimization, these governing nonlinear equations can be solved successfully with any initial solution, and the process of numerical calculation is very stable. For the calculations of cable configuration and tension of marine cables under complex currents, the proposed separated swarm particle optimization is more effective than the other particle swarm optimizations.

Micro-Raman spectroscopy studies of the phase separation mechanisms of transition-metal phosphate glasses

International Nuclear Information System (INIS)

Mazali, Italo Odone; Alves, Oswaldo Luiz; Gimenez, Iara de Fatima

2009-01-01

Glass-ceramics are prepared by controlled separation of crystal phases in glasses, leading to uniform and dense grain structures. On the other hand, chemical leaching of soluble crystal phases yields porous glass-ceramics with important applications. Here, glass/ceramic interfaces of niobo-, vanado- and titano-phosphate glasses were studied by micro-Raman spectroscopy, whose spatial resolution revealed the multiphase structures. Phase-separation mechanisms were also determined by this technique, revealing that interface composition remained unchanged as the crystallization front advanced for niobo- and vanadophosphate glasses (interface-controlled crystallization). For titanophosphate glasses, phase composition changed continuously with time up to the equilibrium composition, indicating a spinodal-type phase separation. (author)

Giant panda׳s tooth enamel: Structure, mechanical behavior and toughening mechanisms under indentation.

Science.gov (United States)

Weng, Z Y; Liu, Z Q; Ritchie, R O; Jiao, D; Li, D S; Wu, H L; Deng, L H; Zhang, Z F

2016-12-01

The giant panda׳s teeth possess remarkable load-bearing capacity and damage resistance for masticating bamboos. In this study, the hierarchical structure and mechanical behavior of the giant panda׳s tooth enamel were investigated under indentation. The effects of loading orientation and location on mechanical properties of the enamel were clarified and the evolution of damage in the enamel under increasing load evaluated. The nature of the damage, both at and beneath the indentation surfaces, and the underlying toughening mechanisms were explored. Indentation cracks invariably were seen to propagate along the internal interfaces, specifically the sheaths between enamel rods, and multiple extrinsic toughening mechanisms, e.g., crack deflection/twisting and uncracked-ligament bridging, were active to shield the tips of cracks from the applied stress. The giant panda׳s tooth enamel is analogous to human enamel in its mechanical properties, yet it has superior hardness and Young׳s modulus but inferior toughness as compared to the bamboo that pandas primarily feed on, highlighting the critical roles of the integration of underlying tissues in the entire tooth and the highly hydrated state of bamboo foods. Our objective is that this study can aid the understanding of the structure-mechanical property relations in the tooth enamel of mammals and further provide some insight on the food habits of the giant pandas. Copyright © 2016 Elsevier Ltd. All rights reserved.

Physical mechanisms in shock-induced turbulent separated flow

Science.gov (United States)

Dolling, D. S.

1987-12-01

It has been demonstrated that the flow downstream of the moving shock is separated and that the foot of the shock is effectively the instantaneous separation point. The shock induced turbulent separation is an intermittant process and the separation line indicated by surface tracer methods, such as kerosene-lampblack, is a downstream boundary of a region of intermittent separation.

Wetting-layer formation mechanisms of surface-directed phase separation under different quench depths with off-critical compositions in polymer binary mixture

Science.gov (United States)

Yan, Li-Tang; Xie, Xu-Ming

2007-02-01

Focusing on the off-critical condition, the quench depth dependence of surface-directed phase separation in the polymer binary mixture is numerically investigated by combination of the Cahn-Hilliard-Cook theory and the Flory-Huggins-de Gennes theory. Two distinct situations, i.e., for the wetting, the minority component is preferred by the surface and the majority component is preferred by the surface, are discussed in detail. The simulated results show that the formation mechanism of the wetting layer is affected by both the quench depth and the off-critical extent. Moreover, a diagram, illustrating the formation mechanisms of the wetting layer with various quench depths and compositions, is obtained on the basis of the simulated results. It is found that, when the minority component is preferred by the surface, the growth of the wetting layer can exhibit pure diffusion limited growth law, logarithmic growth law, and Lifshitz-Slyozov growth law. However, when the majority component is preferred by the surface, the wetting layer always grows logarithmically, regardless of the quench depth and the off-critical extent. It is interesting that the surface-induced nucleation can be observed in this case. The simulated results demonstrate that the surface-induced nucleation only occurs below a certain value of the quench depth, and a detailed range about it is calculated and indicated. Furthermore, the formation mechanisms of the wetting layer are theoretically analyzed in depth by the chemical potential gradient.

Magnetically separable nanoferrite-anchored glutathione: Aqueous homocoupling of arylboronic acids under microwave irradiation

Science.gov (United States)

A highly active, stable and magnetically separable glutathione based organocatalyst provided good to excellent yields to symmetric biaryls in the homocoupling of arylboronic acids under microwave irradiation. Symmetrical biaryl motifs are present in a wide range of natural p...

CRDM with separate SCRAM latch engagement and locking

Energy Technology Data Exchange (ETDEWEB)

Dodd, Christopher D.; DeSantis, Paul K.; Stambaugh, Kevin J.; Mackovjak, Allan R.; McLaughlin, John P.; Goodyear, Brett T.; Edwards, Michael J.; Ales, Matthew W.

2018-01-09

A control rod drive mechanism (CRDM) configured to latch onto the lifting rod of a control rod assembly and including separate latch engagement and latch holding mechanisms. A CRDM configured to latch onto the lifting rod of a control rod assembly and including a four-bar linkage closing the latch, wherein the four-bar linkage biases the latch closed under force of gravity.

Evaluation of enrichment by centrifugal separation: the future of the centrifugal-separation method

International Nuclear Information System (INIS)

Kanagawa, A.

A gas centrifuge plant for uranium enrichment is considered from the point of view of economic competition with other methods. Characteristics of the method are presented including: energy efficiency, the cascade, the separation coefficient, the equilibrium separation process, and capability as centrifugal pump. The structure of an individual gas centrifuge separator is described including the rotating cylinder, mechanisms for gas injection and extraction, mechanisms for counter-streaming of gas, the axle holder mechanism, the gas sealing mechanism, and the driving mechanism. (U.S.)

Peeling mechanism of tomato under infrared heating

Science.gov (United States)

Critical behaviors of peeling tomatoes using infrared heat are thermally induced peel loosening and subsequent cracking. However, the mechanism of peel loosening and cracking due to infrared heating remains unclear. This study aimed at investigating the mechanism of peeling tomatoes under infrared h...

Possible Mechanisms Underlying the Therapeutic Effects of Transcranial Magnetic Stimulation

Science.gov (United States)

Chervyakov, Alexander V.; Chernyavsky, Andrey Yu.; Sinitsyn, Dmitry O.; Piradov, Michael A.

2015-01-01

Transcranial magnetic stimulation (TMS) is an effective method used to diagnose and treat many neurological disorders. Although repetitive TMS (rTMS) has been used to treat a variety of serious pathological conditions including stroke, depression, Parkinson’s disease, epilepsy, pain, and migraines, the pathophysiological mechanisms underlying the effects of long-term TMS remain unclear. In the present review, the effects of rTMS on neurotransmitters and synaptic plasticity are described, including the classic interpretations of TMS effects on synaptic plasticity via long-term potentiation and long-term depression. We also discuss the effects of rTMS on the genetic apparatus of neurons, glial cells, and the prevention of neuronal death. The neurotrophic effects of rTMS on dendritic growth and sprouting and neurotrophic factors are described, including change in brain-derived neurotrophic factor concentration under the influence of rTMS. Also, non-classical effects of TMS related to biophysical effects of magnetic fields are described, including the quantum effects, the magnetic spin effects, genetic magnetoreception, the macromolecular effects of TMS, and the electromagnetic theory of consciousness. Finally, we discuss possible interpretations of TMS effects according to dynamical systems theory. Evidence suggests that a rTMS-induced magnetic field should be considered a separate physical factor that can be impactful at the subatomic level and that rTMS is capable of significantly altering the reactivity of molecules (radicals). It is thought that these factors underlie the therapeutic benefits of therapy with TMS. Future research on these mechanisms will be instrumental to the development of more powerful and reliable TMS treatment protocols. PMID:26136672

Full-scale demonstration of treatment of mechanically separated organic residue in a bioreactor at VAM in Wijster

NARCIS (Netherlands)

Oonk, H.; Woelders, H.

1999-01-01

At the VAM waste treatment company in Wijster a demonstration is in progress of bioreactor technology for the treatment of mechanically separated organic residue (MSOR) of a waste separation plant. This bioreactor is an in situ fermentation cell in which physical, chemical and biological processes

Deciphering the Cognitive and Neural Mechanisms Underlying ...

International Development Research Centre (IDRC) Digital Library (Canada)

Deciphering the Cognitive and Neural Mechanisms Underlying Auditory Learning. This project seeks to understand the brain mechanisms necessary for people to learn to perceive sounds. Neural circuits and learning. The research team will test people with and without musical training to evaluate their capacity to learn ...

Thermal separation of soil particles from thermal conductivity measurement under various air pressures.

Science.gov (United States)

Lu, Sen; Ren, Tusheng; Lu, Yili; Meng, Ping; Zhang, Jinsong

2017-01-05

The thermal conductivity of dry soils is related closely to air pressure and the contact areas between solid particles. In this study, the thermal conductivity of two-phase soil systems was determined under reduced and increased air pressures. The thermal separation of soil particles, i.e., the characteristic dimension of the pore space (d), was then estimated based on the relationship between soil thermal conductivity and air pressure. Results showed that under both reduced and increased air pressures, d estimations were significantly larger than the geometrical mean separation of solid particles (D), which suggested that conductive heat transfer through solid particles dominated heat transfer in dry soils. The increased air pressure approach gave d values lower than that of the reduced air pressure method. With increasing air pressure, more collisions between gas molecules and solid surface occurred in micro-pores and intra-aggregate pores due to the reduction of mean free path of air molecules. Compared to the reduced air pressure approach, the increased air pressure approach expressed more micro-pore structure attributes in heat transfer. We concluded that measuring thermal conductivity under increased air pressure procedures gave better-quality d values, and improved soil micro-pore structure estimation.

Enrichment of the metallic components from waste printed circuit boards by a mechanical separation process using a stamp mill

International Nuclear Information System (INIS)

Yoo, Jae-Min; Jeong, Jinki; Yoo, Kyoungkeun; Lee, Jae-chun; Kim, Wonbaek

2009-01-01

Printed circuit boards incorporated in most electrical and electronic equipment contain valuable metals such as Cu, Ni, Au, Ag, Pd, Fe, Sn, and Pb. In order to employ a hydrometallurgical route for the recycling of valuable metals from printed circuit boards, a mechanical pre-treatment step is needed. In this study, the metallic components from waste printed circuit boards have been enriched using a mechanical separation process. Waste printed circuit boards shredded to 5.0 mm. The fractions of milled printed circuit boards of size 5.0 mm fraction and the heavy fraction were subjected to two-step magnetic separation. Through the first magnetic separation at 700 Gauss, 83% of the nickel and iron, based on the whole printed circuit boards, was recovered in the magnetic fraction, and 92% of the copper was recovered in the non-magnetic fraction. The cumulative recovery of nickel-iron concentrate was increased by a second magnetic separation at 3000 Gauss, but the grade of the concentrate decreased remarkably from 76% to 56%. The cumulative recovery of copper concentrate decreased, but the grade increased slightly from 71.6% to 75.4%. This study has demonstrated the feasibility of the mechanical separation process consisting of milling/size classification/gravity separation/two-step magnetic separation for enriching metallic components such as Cu, Ni, Al, and Fe from waste printed circuit boards

Gas Bubble Dynamics under Mechanical Vibrations

Science.gov (United States)

Mohagheghian, Shahrouz; Elbing, Brian

2017-11-01

The scientific community has a limited understanding of the bubble dynamics under mechanical oscillations due to over simplification of Navier-Stockes equation by neglecting the shear stress tensor and not accounting for body forces when calculating the acoustic radiation force. The current work experimental investigates bubble dynamics under mechanical vibration and resulting acoustic field by measuring the bubble size and velocity using high-speed imaging. The experimental setup consists of a custom-designed shaker table, cast acrylic bubble column, compressed air injection manifold and an optical imaging system. The mechanical vibrations resulted in accelerations between 0.25 to 10 times gravitational acceleration corresponding to frequency and amplitude range of 8 - 22Hz and 1 - 10mm respectively. Throughout testing the void fraction was limited to <5%. The bubble size is larger than resonance size and smaller than acoustic wavelength. The amplitude of acoustic pressure wave was estimated using the definition of Bjerknes force in combination with Rayleigh-Plesset equation. Physical behavior of the system was capture and classified. Bubble size, velocity as well as size and spatial distribution will be presented.

Genomic interrogation of mechanism(s) underlying cellular responses to toxicants

International Nuclear Information System (INIS)

Amin, Rupesh P.; Hamadeh, Hisham K.; Bushel, Pierre R.; Bennett, Lee; Afshari, Cynthia A.; Paules, Richard S.

2002-01-01

Assessment of the impact of xenobiotic exposure on human health and disease progression is complex. Knowledge of mode(s) of action, including mechanism(s) contributing to toxicity and disease progression, is valuable for evaluating compounds. Toxicogenomics, the subdiscipline which merges genomics with toxicology, holds the promise to contributing significantly toward the goal of elucidating mechanism(s) by studying genome-wide effects of xenobiotics. Global gene expression profiling, revolutionized by microarray technology and a crucial aspect of a toxicogenomic study, allows measuring transcriptional modulation of thousands of genes following exposure to a xenobiotic. We use our results from previous studies on compounds representing two different classes of xenobiotics (barbiturate and peroxisome proliferator) to discuss the application of computational approaches for analyzing microarray data to elucidate mechanism(s) underlying cellular responses to toxicants. In particular, our laboratory demonstrated that chemical-specific patterns of gene expression can be revealed using cDNA microarrays. Transcript profiling provides discrimination between classes of toxicants, as well as, genome-wide insight into mechanism(s) of toxicity and disease progression. Ultimately, the expectation is that novel approaches for predicting xenobiotic toxicity in humans will emerge from such information

POSSIBLE MECHANISMS UNDERLYING THE THERAPEUTIC EFFECTS OF TRANSCRANIAL MAGNETIC STIMULATION

Directory of Open Access Journals (Sweden)

Alexander eChervyakov

2015-06-01

Full Text Available Transcranial magnetic stimulation (TMS is an effective method used to diagnose and treat many neurological disorders. Although repetitive TMS (rTMS has been used to treat a variety of serious pathological conditions including stroke, depression, Parkinson's disease, epilepsy, pain, and migraines, the pathophysiological mechanisms underlying the effects of long-term TMS remain unclear. In the present review, the effects of rTMS on neurotransmitters and synaptic plasticity are described, including the classic interpretations of TMS effects on synaptic plasticity via long-term potentiation (LTP and long-term depression (LTD. We also discuss the effects of rTMS on the genetic apparatus of neurons, glial cells and the prevention of neuronal death. The neurotrophic effects of rTMS on dendritic growth and sprouting and neurotrophic factors are described, including change in brain-derived neurotrophic factor (BDNF concentration under the influence of rTMS. Also, non-classical effects of TMS related to biophysical effects of magnetic fields are described, including the quantum effects, the magnetic spin effects, genetic magnetoreception, the macromolecular effects of TMS, and the electromagnetic theory of consciousness. Finally, we discuss possible interpretations of TMS effects according to dynamical systems theory. Evidence suggests that a rTMS-induced magnetic field should be considered a separate physical factor that can be impactful at the subatomic level and that rTMS is capable of significantly altering the reactivity of molecules (radicals. It is thought that these factors underlie the therapeutic benefits of therapy with TMS. Future research on these mechanisms will be instrumental to the development of more powerful and reliable TMS treatment protocols.

Modeling and testing of a tube-in-tube separation mechanism of bodies in space

Science.gov (United States)

Michaels, Dan; Gany, Alon

2016-12-01

A tube-in-tube concept for separation of bodies in space was investigated theoretically and experimentally. The separation system is based on generation of high pressure gas by combustion of solid propellant and restricting the expansion of the gas only by ejecting the two bodies in opposite directions, in such a fashion that maximizes generated impulse. An interior ballistics model was developed in order to investigate the potential benefits of the separation system for a large range of space body masses and for different design parameters such as geometry and propellant. The model takes into account solid propellant combustion, heat losses, and gas phase chemical reactions. The model shows that for large bodies (above 100 kg) and typical separation velocities of 5 m/s, the proposed separation mechanism may be characterized by a specific impulse of 25,000 s, two order of magnitude larger than that of conventional solid rockets. It means that the proposed separation system requires only 1% of the propellant mass that would be needed for a conventional rocket for the same mission. Since many existing launch vehicles obtain such separation velocities by using conventional solid rocket motors (retro-rockets), the implementation of the new separation system design can reduce dramatically the mass of the separation system and increase safety. A dedicated experimental setup was built in order to demonstrate the concept and validate the model. The experimental results revealed specific impulse values of up to 27,000 s and showed good correspondence with the model.

Interaction mechanisms of cavitation bubbles induced by spatially and temporally separated fs-laser pulses.

Directory of Open Access Journals (Sweden)

Nadine Tinne

Full Text Available The emerging use of femtosecond lasers with high repetition rates in the MHz regime together with limited scan speed implies possible mutual optical and dynamical interaction effects of the individual cutting spots. In order to get more insight into the dynamics a time-resolved photographic analysis of the interaction of cavitation bubbles is presented. Particularly, we investigated the influence of fs-laser pulses and their resulting bubble dynamics with various spatial as well as temporal separations. Different time courses of characteristic interaction effects between the cavitation bubbles were observed depending on pulse energy and spatio-temporal pulse separation. These ranged from merely no interaction to the phenomena of strong water jet formation. Afterwards, the mechanisms are discussed regarding their impact on the medical application of effective tissue cutting lateral to the laser beam direction with best possible axial precision: the mechanical forces of photodisruption as well as the occurring water jet should have low axial extend and a preferably lateral priority. Furthermore, the overall efficiency of energy conversion into controlled mechanical impact should be maximized compared to the transmitted pulse energy and unwanted long range mechanical side effects, e.g. shock waves, axial jet components. In conclusion, these experimental results are of great importance for the prospective optimization of the ophthalmic surgical process with high-repetition rate fs-lasers.

On the role of fibril mechanics in the work of separation of fibrillating interfaces

NARCIS (Netherlands)

Vossen, B.G.; Sluis, van der O.; Schreurs, P.J.G.; Geers, M.G.D.; Neggers, J.; Hoefnagels, J.P.M.

2015-01-01

High values for the work of separation have been reported in peel tests on fibrillating interfacial systems. The exact origin of these high values is not properly understood, since it remains unclear which dissipative mechanisms related to fibrillation cause a significant increase in the work of

Probing neural mechanisms underlying auditory stream segregation in humans by transcranial direct current stimulation (tDCS).

Science.gov (United States)

Deike, Susann; Deliano, Matthias; Brechmann, André

2016-10-01

One hypothesis concerning the neural underpinnings of auditory streaming states that frequency tuning of tonotopically organized neurons in primary auditory fields in combination with physiological forward suppression is necessary for the separation of representations of high-frequency A and low-frequency B tones. The extent of spatial overlap between the tonotopic activations of A and B tones is thought to underlie the perceptual organization of streaming sequences into one coherent or two separate streams. The present study attempts to interfere with these mechanisms by transcranial direct current stimulation (tDCS) and to probe behavioral outcomes reflecting the perception of ABAB streaming sequences. We hypothesized that tDCS by modulating cortical excitability causes a change in the separateness of the representations of A and B tones, which leads to a change in the proportions of one-stream and two-stream percepts. To test this, 22 subjects were presented with ambiguous ABAB sequences of three different frequency separations (∆F) and had to decide on their current percept after receiving sham, anodal, or cathodal tDCS over the left auditory cortex. We could confirm our hypothesis at the most ambiguous ∆F condition of 6 semitones. For anodal compared with sham and cathodal stimulation, we found a significant decrease in the proportion of two-stream perception and an increase in the proportion of one-stream perception. The results demonstrate the feasibility of using tDCS to probe mechanisms underlying auditory streaming through the use of various behavioral measures. Moreover, this approach allows one to probe the functions of auditory regions and their interactions with other processing stages. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Two-dimensional materials for novel liquid separation membranes

Science.gov (United States)

Ying, Yulong; Yang, Yefeng; Ying, Wen; Peng, Xinsheng

2016-08-01

Demand for a perfect molecular-level separation membrane with ultrafast permeation and a robust mechanical property for any kind of species to be blocked in water purification and desalination is urgent. In recent years, due to their intrinsic characteristics, such as a unique mono-atom thick structure, outstanding mechanical strength and excellent flexibility, as well as facile and large-scale production, graphene and its large family of two-dimensional (2D) materials are regarded as ideal membrane materials for ultrafast molecular separation. A perfect separation membrane should be as thin as possible to maximize its flux, mechanically robust and without failure even if under high loading pressure, and have a narrow nanochannel size distribution to guarantee its selectivity. The latest breakthrough in 2D material-based membranes will be reviewed both in theories and experiments, including their current state-of-the-art fabrication, structure design, simulation and applications. Special attention will be focused on the designs and strategies employed to control microstructures to enhance permeation and selectivity for liquid separation. In addition, critical views on the separation mechanism within two-dimensional material-based membranes will be provided based on a discussion of the effects of intrinsic defects during growth, predefined nanopores and nanochannels during subsequent fabrication processes, the interlayer spacing of stacking 2D material flakes and the surface charge or functional groups. Furthermore, we will summarize the significant progress of these 2D material-based membranes for liquid separation in nanofiltration/ultrafiltration and pervaporation. Lastly, we will recall issues requiring attention, and discuss existing questionable conclusions in some articles and emerging challenges. This review will serve as a valuable platform to provide a compact source of relevant and timely information about the development of 2D material-based membranes as

Two-dimensional materials for novel liquid separation membranes.

Science.gov (United States)

Ying, Yulong; Yang, Yefeng; Ying, Wen; Peng, Xinsheng

2016-08-19

Demand for a perfect molecular-level separation membrane with ultrafast permeation and a robust mechanical property for any kind of species to be blocked in water purification and desalination is urgent. In recent years, due to their intrinsic characteristics, such as a unique mono-atom thick structure, outstanding mechanical strength and excellent flexibility, as well as facile and large-scale production, graphene and its large family of two-dimensional (2D) materials are regarded as ideal membrane materials for ultrafast molecular separation. A perfect separation membrane should be as thin as possible to maximize its flux, mechanically robust and without failure even if under high loading pressure, and have a narrow nanochannel size distribution to guarantee its selectivity. The latest breakthrough in 2D material-based membranes will be reviewed both in theories and experiments, including their current state-of-the-art fabrication, structure design, simulation and applications. Special attention will be focused on the designs and strategies employed to control microstructures to enhance permeation and selectivity for liquid separation. In addition, critical views on the separation mechanism within two-dimensional material-based membranes will be provided based on a discussion of the effects of intrinsic defects during growth, predefined nanopores and nanochannels during subsequent fabrication processes, the interlayer spacing of stacking 2D material flakes and the surface charge or functional groups. Furthermore, we will summarize the significant progress of these 2D material-based membranes for liquid separation in nanofiltration/ultrafiltration and pervaporation. Lastly, we will recall issues requiring attention, and discuss existing questionable conclusions in some articles and emerging challenges. This review will serve as a valuable platform to provide a compact source of relevant and timely information about the development of 2D material-based membranes as

A novel approach to mechanical foot stimulation during human locomotion under body weight support.

Science.gov (United States)

Gravano, S; Ivanenko, Y P; Maccioni, G; Macellari, V; Poppele, R E; Lacquaniti, F

2011-04-01

Input from the foot plays an essential part in perceiving support surfaces and determining kinematic events in human walking. To simulate adequate tactile pressure inputs under body weight support (BWS) conditions that represent an effective form of locomotion training, we here developed a new method of phasic mechanical foot stimulation using light-weight pneumatic insoles placed inside the shoes (under the heel and metatarsus). To test the system, we asked healthy participants to walk on a treadmill with different levels of BWS. The pressure under the stimulated areas of the feet and subjective sensations were higher at high levels of BWS and when applied to the ball and toes rather than heels. Foot stimulation did not disturb significantly the normal motor pattern, and in all participants we evoked a reliable step-synchronized triggering of stimuli for each leg separately. This approach has been performed in a general framework looking for "afferent templates" of human locomotion that could be used for functional sensory stimulation. The proposed technique can be used to imitate or partially restore surrogate contact forces under body weight support conditions. Copyright © 2010 Elsevier B.V. All rights reserved.

Dynein Transmits Polarized Actomyosin Cortical Flows to Promote Centrosome Separation

Directory of Open Access Journals (Sweden)

Alessandro De Simone

2016-03-01

Full Text Available The two centrosomes present at the onset of mitosis must separate in a timely and accurate fashion to ensure proper bipolar spindle assembly. The minus-end-directed motor dynein plays a pivotal role in centrosome separation, but the underlying mechanisms remain elusive, particularly regarding how dynein coordinates this process in space and time. We addressed these questions in the one-cell C. elegans embryo, using a combination of 3D time-lapse microscopy and computational modeling. Our analysis reveals that centrosome separation is powered by the joint action of dynein at the nuclear envelope and at the cell cortex. Strikingly, we demonstrate that dynein at the cell cortex acts as a force-transmitting device that harnesses polarized actomyosin cortical flows initiated by the centrosomes earlier in the cell cycle. This mechanism elegantly couples cell polarization with centrosome separation, thus ensuring faithful cell division.

9 CFR 381.174 - Limitations with respect to use of Mechanically Separated (Kind of Poultry).

Science.gov (United States)

2010-01-01

... Mechanically Separated (Kind of Poultry). 381.174 Section 381.174 Animals and Animal Products FOOD SAFETY AND INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE AGENCY ORGANIZATION AND TERMINOLOGY; MANDATORY MEAT AND POULTRY PRODUCTS INSPECTION AND VOLUNTARY INSPECTION AND CERTIFICATION POULTRY PRODUCTS INSPECTION REGULATIONS...

Photocatalytic degradation of methylene blue on magnetically separable MgFe2O4 under visible light irradiation

International Nuclear Information System (INIS)

Shahid, Muhammad; Jingling, Liu; Ali, Zahid; Shakir, Imran; Warsi, Muhammad Farooq; Parveen, Riffat; Nadeem, Muhammad

2013-01-01

A magnetically separable single-phase MgFe 2 O 4 photocatalyst with a spinel crystal structure was synthesized by using the solid-state reaction method. The formation of spinel structure is confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The magnetic measurements showed that the photocatalyst material can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for waste water treatment. The photocatalytic activity of MgFe 2 O 4 was investigated by using the photo-decomposition of methylene blue dye under visible light. The photoelectrochemical property of the MgFe 2 O 4 was studied by measuring their photocurrent–potential behavior in 1 M NaOH electrolyte under AM 1.5100 mW cm −2 illumination. - Graphical abstract: Highly efficient magnetically separable MgFe 2 O 4 photocatalyst for organic based impurities decomposition as well as for the production of H 2 gas was synthesized and characterized successfully (a) MgFe 2 O 4 photocatalyst in polluted water, (b) The photocatalyst (MgFe 2 O 4 ) is being attracted toward magnetic field for separation, (c) Hysteresis loop of MgFe 2 O 4 showing magnetic behavior. Highlights: ► New photocatalyst working in the visible range have been synthesized by facile cheap route. ► MgFe 2 O 4 photocatalyst showed well defined magnetically separable behavior. ► Excellent water splitting characteristics to produce H 2 was observed under visible light irradiation

Neural Mechanisms Underlying Risk and Ambiguity Attitudes.

Science.gov (United States)

Blankenstein, Neeltje E; Peper, Jiska S; Crone, Eveline A; van Duijvenvoorde, Anna C K

2017-11-01

Individual differences in attitudes to risk (a taste for risk, known probabilities) and ambiguity (a tolerance for uncertainty, unknown probabilities) differentially influence risky decision-making. However, it is not well understood whether risk and ambiguity are coded differently within individuals. Here, we tested whether individual differences in risk and ambiguity attitudes were reflected in distinct neural correlates during choice and outcome processing of risky and ambiguous gambles. To these ends, we developed a neuroimaging task in which participants ( n = 50) chose between a sure gain and a gamble, which was either risky or ambiguous, and presented decision outcomes (gains, no gains). From a separate task in which the amount, probability, and ambiguity level were varied, we estimated individuals' risk and ambiguity attitudes. Although there was pronounced neural overlap between risky and ambiguous gambling in a network typically related to decision-making under uncertainty, relatively more risk-seeking attitudes were associated with increased activation in valuation regions of the brain (medial and lateral OFC), whereas relatively more ambiguity-seeking attitudes were related to temporal cortex activation. In addition, although striatum activation was observed during reward processing irrespective of a prior risky or ambiguous gamble, reward processing after an ambiguous gamble resulted in enhanced dorsomedial PFC activation, possibly functioning as a general signal of uncertainty coding. These findings suggest that different neural mechanisms reflect individual differences in risk and ambiguity attitudes and that risk and ambiguity may impact overt risk-taking behavior in different ways.

Harnessing electro driven separation technique for the separation of selected agrochemicals

International Nuclear Information System (INIS)

Wan Aini Wan Ibrahim; Alam, S.M. Monjurul; Azli Sulaiman

2008-01-01

Electro driven separation techniques offer a different approach to the analysis of complex mixtures than do traditional pressure-driven chromatographic system; it may rely on electrophoresis, the transport of charged species through a medium by an applied field or may rely on electro driven mobile phase to provide a true chromatographic separation. In the current work the potential of an electro driven separation technique viz. Micellar electrokinetic chromatography (MEKC), is harnessed for the separation of selected agrochemicals (organophosphorus pesticides, OPPs) widely used in the agriculture sector in Malaysia. The current study compares the use of MEKC in normal mode (NM) and reverse mode (RM) for the separation of the selected OPPS. This study also highlights the difference in separations produced by performing separations in normal mode-MEKC (NM-MEKC) and reverse mode-MEKC (RM-MEKC) for the selected OPPs. In RM-MEKC, separation is conducted at acidic pH (pH 2.5 in the current work) where the electro osmotic flow (EOF) is weak whereas in NM-MEKC, the separation is carried out under basic pH (9.3 in this work) where the EOF is strong. A reverse migration order of the OPPs was observed under RM-MEKC. Separation under NM-MEKC was found to be superior to those of RM- MEKC. A comparison is also made between separations performed under sweeping-NM-MEKC and sweeping-RM-MEKC. In sweeping, the OPPs are prepared in the same background solution (BGS) minus the micelles and is adjusted to the same conductivity as the BGS. The study showed that NM-MEKC is more sensitive than RM-MEKC but sweeping-RM-MEKC is superior to sweeping-NM-MEKC. However, sweeping-RM-MEKC only separates two of the OPPs in a single run whereas sweeping-NM-MEKC separates four OPPs in a single run. The better choice of separation mode would be sweeping-NM- MEKC for more OPPs separation in a single run. (author)

Are carnivore digestive separation mechanisms revealed on structure-rich diets?: Faecal inconsistency in dogs (Canis familiaris fed day old chicks.

Directory of Open Access Journals (Sweden)

Annelies De Cuyper

Full Text Available Pronounced variations in faecal consistency have been described anecdotally for some carnivore species fed a structure-rich diet. Typically two faecal consistencies are distinguished, namely hard and firm versus liquid and viscous faeces. It is possible that a separation mechanism is operating in the carnivore digestive tract, as in many herbivore species. Six beagle dogs were fed two experimental diets in a cross-over design of 7 days. Test diets consisted of chunked day old chicks differing only in particle size (fine = 7.8 mm vs coarse = 13 mm in order to vary dietary structure. Digestive retention time was measured using titanium oxide (TiO2 as marker. The total faecal output was scored for consistency and faecal fermentation profiles were evaluated through faecal short-chain fatty acid (SCFA and ammonia (NH3 analyses. A total of 181 faecal samples were collected. Dietary particle size did not affect faecal consistency, fermentative end products nor mean retention time (MRT. However, a faecal consistency dichotomy was observed with firm faeces (score 2-2.5 and soft faeces (score 4-4.5 being the most frequently occurring consistencies in an almost alternating pattern in every single dog. Firm and soft faeces differed distinctively in fermentative profiles. Although the structure difference between diets did not affect the faecal dichotomy, feeding whole prey provoked the occurrence of the latter which raises suspicion of a digestive separation mechanism in the canine digestive tract. Further faecal characterisation is however required in order to unravel the underlying mechanism.

5 CFR 837.802 - Benefits under another retirement system for Federal employees based on the most recent separation.

Science.gov (United States)

2010-01-01

... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Benefits under another retirement system for Federal employees based on the most recent separation. 837.802 Section 837.802 Administrative... system for Federal employees based on the most recent separation. (a) Generally. An annuitant who has...

Development of an Inclined Plate Extractor-Separator for Immiscible Liquids

Directory of Open Access Journals (Sweden)

Syed Zahoor ul Hassan Rizvi

2009-10-01

Full Text Available A new inclined plates extractor-separator is developed for operation with immiscible liquids in which extraction and separation is achieved in one unit contrary to mixer settlers. The inclined plates extractor-separator combines turbulent jets for contacting, and an inclined plate for separation of the two phases. The inclined plates extractor-separator does not have any moving part inside the vessel. This feature makes it free from the mechanical problems associated with conventional apparatus. The proposed inclined plates extractor-separator was operated in batch mode under various operating conditions to evaluate its performance on the basis of extraction efficiency. Water (light phase was used as solvent to extract ethyl acetate from a heavy phase pool of tetrachloroethylene and ethyl acetate. The ethyl acetate content was analysed using chromatography. A hydrodynamic study was carried out using high speed photography to understand the mechanisms occurring during mass transfer across the two phases. Furthermore, it was found that the proposed inclined plate extractor-separator reduces the overall operating time by 67% and consumes only 13% of the power in comparison to a mixer-settler. A hydraulic power consumption comparison with a mixer settler and a gullwing extractor-separator is also presented.

RELATION BETWEEN MECHANICAL PROPERTIES AND PYROLYSIS TEMPERATURE OF PHENOL FORMALDEHYDE RESIN FOR GAS SEPARATION MEMBRANES

Directory of Open Access Journals (Sweden)

MONIKA ŠUPOVÁ

2012-03-01

Full Text Available The aim of this paper has been to characterize the relation between the pyrolysis temperature of phenol-formaldehyde resin, the development of a porous structure, and the mechanical properties for the application of semipermeable membranes for gas separation. No previous study has dealt with this problem in its entirety. Phenol-formaldehyde resin showed an increasing trend toward micropore porosity in the temperature range from 500 till 1000°C, together with closure of mesopores and macropores. Samples cured and pyrolyzed at 1000°C pronounced hysteresis of desorption branch. The ultimate bending strength was measured using a four-point arrangement that is more suitable for measuring of brittle materials. The chevron notch technique was used for determination the fracture toughness. The results for mechanical properties indicated that phenol-formaldehyde resin pyrolyzates behaved similarly to ceramic materials. The data obtained for the material can be used for calculating the technical design of gas separation membranes.

Separation Mechanism of Fatty Acids from Waste Cooking Oil and Its Flotation Performance in Iron Ore Desiliconization

Directory of Open Access Journals (Sweden)

Wenda Guo

2017-12-01

Full Text Available Using the mixed fatty acids (MFA produced by waste cooking oil as flotation collectors directly, the flotation effect is usually not satisfactory, especially at lower temperature, which may be due to the presence of large amounts of saturated fatty acids. In this study, waste cooking oil was separated into saturated fatty acids (SFA and unsaturated fatty acids (UFA. The separation mechanism was studied by molecular simulation based on quantum and molecular mechanics. SFA and UFA were analyzed by iodine value, melting point measurement and Fourier transform infrared (FT-IR spectroscopy to check the result of the separation. The micro-flotation and bench-scale flotation tests were performed to investigate the flotation differences between SFA and UFA. The results showed that the poor flotation performance of waste cooking oil was due to the large amount of SFA in presence. If the SFA was separated out, the TFe grade and recovery of the flotation concentrates would be increased by 4.09 and 2.70 percentage points, respectively and the SiO2 grade would be 4.03 percentage points lower at the same time. This study would provide technical supports and theoretical guidance for the waste cooking oil application in the field of mineral processing.

Separation of argon isotopes by porous membrane method, (2)

International Nuclear Information System (INIS)

Yoshida, Hiroshi; Fujine, Sachio; Saito, Keiichiro; Ouchi, Misao; Naruse, Yuji

1979-08-01

Separation characteristics of an engineering-scale cascade equipment, which is composed of five stages using Al 2 O 3 barriers, were examined under different operating conditions. This report describes the results of the separation experiment of argon isotopes by the square cascade operated under total reflux. The results are as follows: (1) Mean pore diameter and tortuosity of the barriers were estimated to be 400A and 13-15, respectively. (2) Flow mechanism through the barriers was proved to be ideal Knudsen flow by measurement of the permeability. (3) The cascade was equilibriated in 30-40 minutes, depending on stage gas inventory. (4) The effect of an operating pressure on the separation factor could be estimated by Knudsen's and Present-deBethune's theories. (5) The stage separation factor could be estimated by the conventional theoretical equations by introducing a correction factor as a function of Reynolds number of the permeating flow through the barriers. (6) An experimental equation to estimate the flow effect on the separation factor was obtained considering velocity and physical properties of the gas in the vicinity of the barrier surface. (author)

Jet-Underlying Event Separation Method for Heavy Ion Collisions at the Relativistic Heavy Ion Collider

OpenAIRE

Hanks, J. A.; Sickles, A. M.; Cole, B. A.; Franz, A.; McCumber, M. P.; Morrison, D. P.; Nagle, J. L.; Pinkenburg, C. H.; Sahlmueller, B.; Steinberg, P.; von Steinkirch, M.; Stone, M.

2012-01-01

Reconstructed jets in heavy ion collisions are a crucial tool for understanding the quark-gluon plasma. The separation of jets from the underlying event is necessary particularly in central heavy ion reactions in order to quantify medium modifications of the parton shower and the response of the surrounding medium itself. There have been many methods proposed and implemented for studying the underlying event substructure in proton-proton and heavy ion collisions. In this paper, we detail a me...

Separation of zeros for source signature identification under reverberant path conditions.

Science.gov (United States)

Hasegawa, Tomomi; Tohyama, Mikio

2011-10-01

This paper presents an approach to distinguishing the zeros representing a sound source from those representing the transfer function on the basis of Lyon's residue-sign model. In machinery noise diagnostics, the source signature must be separated from observation records under reverberant path conditions. In numerical examples and an experimental piano-string vibration analysis, the modal responses could be synthesized by using clustered line-spectrum modeling. The modeling error represented the source signature subject to the source characteristics being given by a finite impulse response. The modeling error can be interpreted as a remainder function necessary for the zeros representing the source signature. © 2011 Acoustical Society of America

Raw mechanically separated chicken meat and salmon protein hydrolysate as protein sources in extruded dog food

DEFF Research Database (Denmark)

Tjernsbekk, M. T.; Tauson, A. H.; Kraugerud, O. F.

2017-01-01

Protein quality was evaluated for mechanically separated chicken meat (MSC) and salmon protein hydrolysate (SPH), and for extruded dog foods where MSC or SPH partially replaced poultry meal (PM). Apparent total tract digestibility (ATTD) of crude protein (CP) and amino acids (AA) in the protein...

Fatigue behaviour of the austenitic steel 1.4550 under mechanical and thermal cyclic loading

Energy Technology Data Exchange (ETDEWEB)

Siegele, D.; Fingerhuth, J.; Varfolomeev, I.; Moroz, S. [Fraunhofer Institute for Mechanics of Materials (IWM), Freiburg (Germany)

2014-07-01

Fatigue behaviour of the austenitic steel 1.4550 (X6CrNiNb18-10) under low-cycle fatigue and high-cycle thermal fatigue was investigated with in two research projects supported by the Federal Ministry of Economic Affairs and Energy and the Ministry of Education and Research. The objectives of the projects were the gain of deep understanding of the damage mechanisms under mechanical and thermal cyclic loading and the development of material models and simulation procedures for an improved lifetime assessment. In comparison to the advanced mechanism based material models engineering computational procedures were proven with respect to their applicability and conservatisms. For thermal cyclic loading, test equipment and technique were developed which allow for cyclic thermal loading with temperature ranges between 1 00 C and 300 C and frequencies between 0.1 and 1 Hz. As a result, tests with a temperature range of 150 C and lower showed no crack formation up to 300,000 cycles. For temperature ranges of 200 C and higher multiple crack patterns were observed with the deepest crack of about 1.3 mm after 1,000,000 cycles, whereas the difference in crack depth between 300,000 and 1,000,000 cycles was negligibly small. To model the fatigue lifetime, the D{sub TMF} damage parameter was applied to the low-cycle fatigue and the thermal, high frequent fatigue tests. For thermal fatigue, the analyses predicted in agreement with the tests crack initiation followed by crack propagation, subsequent retardation and arrest. This behaviour can be explained qualitatively and quantitatively using the methods of linear-elastic fracture mechanics, whereas the consideration of the interaction of multiple cracks is essential to describe the experimentally observed crack retardation. The results for thermal fatigue are in the scatterband of the mechanical p and thermo-mechanical fatigue results and the cycles to failure are 10 times higher than those estimated according to the KTA fatigue

Separating monocular and binocular neural mechanisms mediating chromatic contextual interactions.

Science.gov (United States)

D'Antona, Anthony D; Christiansen, Jens H; Shevell, Steven K

2014-04-17

When seen in isolation, a light that varies in chromaticity over time is perceived to oscillate in color. Perception of that same time-varying light may be altered by a surrounding light that is also temporally varying in chromaticity. The neural mechanisms that mediate these contextual interactions are the focus of this article. Observers viewed a central test stimulus that varied in chromaticity over time within a larger surround that also varied in chromaticity at the same temporal frequency. Center and surround were presented either to the same eye (monocular condition) or to opposite eyes (dichoptic condition) at the same frequency (3.125, 6.25, or 9.375 Hz). Relative phase between center and surround modulation was varied. In both the monocular and dichoptic conditions, the perceived modulation depth of the central light depended on the relative phase of the surround. A simple model implementing a linear combination of center and surround modulation fit the measurements well. At the lowest temporal frequency (3.125 Hz), the surround's influence was virtually identical for monocular and dichoptic conditions, suggesting that at this frequency, the surround's influence is mediated primarily by a binocular neural mechanism. At higher frequencies, the surround's influence was greater for the monocular condition than for the dichoptic condition, and this difference increased with temporal frequency. Our findings show that two separate neural mechanisms mediate chromatic contextual interactions: one binocular and dominant at lower temporal frequencies and the other monocular and dominant at higher frequencies (6-10 Hz).

DNA under Force: Mechanics, Electrostatics, and Hydration

Directory of Open Access Journals (Sweden)

Jingqiang Li

2015-02-01

Full Text Available Quantifying the basic intra- and inter-molecular forces of DNA has helped us to better understand and further predict the behavior of DNA. Single molecule technique elucidates the mechanics of DNA under applied external forces, sometimes under extreme forces. On the other hand, ensemble studies of DNA molecular force allow us to extend our understanding of DNA molecules under other forces such as electrostatic and hydration forces. Using a variety of techniques, we can have a comprehensive understanding of DNA molecular forces, which is crucial in unraveling the complex DNA functions in living cells as well as in designing a system that utilizes the unique properties of DNA in nanotechnology.

Separation of atropisomers by chiral liquid chromatography and thermodynamic analysis of separation mechanism

Directory of Open Access Journals (Sweden)

Ling Zhang

2017-06-01

Full Text Available In the pharmaceutical industry, the analysis of atropisomers is of considerable interest from a scientific and regulatory perspective. The compound of interest contains two stereogenic axes due to the hindered rotation around the single bonds connecting the aryl groups, which results in four potential configurational isomers (atropisomers. The separation of the four atropisomers is achieved on a derivatized β-cyclodextrin bonded stationary phase. Further investigation shows that low temperature conditions, including sample preparation (−70 °C, sample storage (−70 °C, and chromatographic separation (6 °C, were critical to preventing interconversion. LC-UV-Laser Polarimetric analysis identified peak 1/2 as a pair of enantiomers and peak 3/4 as another. Thermodynamic analysis of the retention data indicated that the separation of the pairs of enantiomers is primarily enthalpy controlled as indicated by the positive slope of the van’t Huff plot. The difference in absolute Δ (Δ H, ranged from 2.20 kJ/mol to 2.42 kJ/mol.

On the problems of separation work unit for the laser isotope separation

International Nuclear Information System (INIS)

Wang, Lijun

2008-01-01

The concept of separation power or separation work, which is widely used in Uranium isotope separation industry is introduced historically for the weak separating machine and so-called 'ideal cascade'. Therefore, when this concept is applied to a laser isotope separation facility, which is deeply different from a cascade in structure and in mechanism of separation, some confusions may occur. By comparison the costs of SWU of laser isotope separation facility and an ideal cascade we come to a conclusion: the concept of separation work is not applicable for laser isotope separation. In order to compare the economics of laser isotope separation technique with diffusion or centrifugation techniques an equivalent cost of SWU is suggested in this paper. (author)

Turing mechanism underlying a branching model for lung morphogenesis.

Science.gov (United States)

Xu, Hui; Sun, Mingzhu; Zhao, Xin

2017-01-01

The mammalian lung develops through branching morphogenesis. Two primary forms of branching, which occur in order, in the lung have been identified: tip bifurcation and side branching. However, the mechanisms of lung branching morphogenesis remain to be explored. In our previous study, a biological mechanism was presented for lung branching pattern formation through a branching model. Here, we provide a mathematical mechanism underlying the branching patterns. By decoupling the branching model, we demonstrated the existence of Turing instability. We performed Turing instability analysis to reveal the mathematical mechanism of the branching patterns. Our simulation results show that the Turing patterns underlying the branching patterns are spot patterns that exhibit high local morphogen concentration. The high local morphogen concentration induces the growth of branching. Furthermore, we found that the sparse spot patterns underlie the tip bifurcation patterns, while the dense spot patterns underlies the side branching patterns. The dispersion relation analysis shows that the Turing wavelength affects the branching structure. As the wavelength decreases, the spot patterns change from sparse to dense, the rate of tip bifurcation decreases and side branching eventually occurs instead. In the process of transformation, there may exists hybrid branching that mixes tip bifurcation and side branching. Since experimental studies have reported that branching mode switching from side branching to tip bifurcation in the lung is under genetic control, our simulation results suggest that genes control the switch of the branching mode by regulating the Turing wavelength. Our results provide a novel insight into and understanding of the formation of branching patterns in the lung and other biological systems.

Adaptive Response in Animals Exposed to Non-Ionizing Radiofrequency Fields: Some Underlying Mechanisms

Directory of Open Access Journals (Sweden)

Yi Cao

2014-04-01

Full Text Available During the last few years, our research group has been investigating the phenomenon of adaptive response in animals exposed to non-ionizing radiofrequency fields. The results from several separate studies indicated a significant increase in survival, decreases in genetic damage as well as oxidative damage and, alterations in several cellular processes in mice pre-exposed to radiofrequency fields and subsequently subjected to sub-lethal or lethal doses of γ-radiation or injected with bleomycin, a radiomimetic chemical mutagen. These observations indicated the induction of adaptive response providing the animals the ability to resist subsequent damage. Similar studies conducted by independent researchers in mice and rats have supported our observation on increased survival. In this paper, we have presented a brief review of all of our own and other independent investigations on radiofrequency fields-induced adaptive response and some underlying mechanisms discussed.

Separators - Technology review: Ceramic based separators for secondary batteries

Energy Technology Data Exchange (ETDEWEB)

Nestler, Tina; Schmid, Robert; Münchgesang, Wolfram; Bazhenov, Vasilii; Meyer, Dirk C. [Technische Universität Bergakademie Freiberg, Institut für Experimentelle Physik, Leipziger Str. 23, 09596 Freiberg (Germany); Schilm, Jochen [Fraunhofer-Institut für Keramische Technologien und Systeme IKTS, Winterbergstraße 28, 01277 Dresden (Germany); Leisegang, Tilmann [Fraunhofer-Technologiezentrum Halbleitermaterialien THM, Am St.-Niclas-Schacht 13, 09599 Freiberg (Germany)

2014-06-16

Besides a continuous increase of the worldwide use of electricity, the electric energy storage technology market is a growing sector. At the latest since the German energy transition ('Energiewende') was announced, technological solutions for the storage of renewable energy have been intensively studied. Storage technologies in various forms are commercially available. A widespread technology is the electrochemical cell. Here the cost per kWh, e. g. determined by energy density, production process and cycle life, is of main interest. Commonly, an electrochemical cell consists of an anode and a cathode that are separated by an ion permeable or ion conductive membrane - the separator - as one of the main components. Many applications use polymeric separators whose pores are filled with liquid electrolyte, providing high power densities. However, problems arise from different failure mechanisms during cell operation, which can affect the integrity and functionality of these separators. In the case of excessive heating or mechanical damage, the polymeric separators become an incalculable security risk. Furthermore, the growth of metallic dendrites between the electrodes leads to unwanted short circuits. In order to minimize these risks, temperature stable and non-flammable ceramic particles can be added, forming so-called composite separators. Full ceramic separators, in turn, are currently commercially used only for high-temperature operation systems, due to their comparably low ion conductivity at room temperature. However, as security and lifetime demands increase, these materials turn into focus also for future room temperature applications. Hence, growing research effort is being spent on the improvement of the ion conductivity of these ceramic solid electrolyte materials, acting as separator and electrolyte at the same time. Starting with a short overview of available separator technologies and the separator market, this review focuses on ceramic

Separators - Technology review: Ceramic based separators for secondary batteries

Science.gov (United States)

Nestler, Tina; Schmid, Robert; Münchgesang, Wolfram; Bazhenov, Vasilii; Schilm, Jochen; Leisegang, Tilmann; Meyer, Dirk C.

2014-06-01

Besides a continuous increase of the worldwide use of electricity, the electric energy storage technology market is a growing sector. At the latest since the German energy transition ("Energiewende") was announced, technological solutions for the storage of renewable energy have been intensively studied. Storage technologies in various forms are commercially available. A widespread technology is the electrochemical cell. Here the cost per kWh, e. g. determined by energy density, production process and cycle life, is of main interest. Commonly, an electrochemical cell consists of an anode and a cathode that are separated by an ion permeable or ion conductive membrane - the separator - as one of the main components. Many applications use polymeric separators whose pores are filled with liquid electrolyte, providing high power densities. However, problems arise from different failure mechanisms during cell operation, which can affect the integrity and functionality of these separators. In the case of excessive heating or mechanical damage, the polymeric separators become an incalculable security risk. Furthermore, the growth of metallic dendrites between the electrodes leads to unwanted short circuits. In order to minimize these risks, temperature stable and non-flammable ceramic particles can be added, forming so-called composite separators. Full ceramic separators, in turn, are currently commercially used only for high-temperature operation systems, due to their comparably low ion conductivity at room temperature. However, as security and lifetime demands increase, these materials turn into focus also for future room temperature applications. Hence, growing research effort is being spent on the improvement of the ion conductivity of these ceramic solid electrolyte materials, acting as separator and electrolyte at the same time. Starting with a short overview of available separator technologies and the separator market, this review focuses on ceramic-based separators

Influence of thermodynamic mechanism of inter- facial adsorption on purifying air-conditioning engineering under intensification of electric field

Directory of Open Access Journals (Sweden)

Chen Yun-Yu

2016-12-01

Full Text Available As a kind of mass transfer process as well as the basis of separating and purifying mixtures, interfacial adsorption has been widely applied to fields like chemical industry, medical industry and purification engineering in recent years. Influencing factors of interfacial adsorption, in addition to the traditional temperature, intensity of pressure, amount of substance and concentration, also include external fields, such as magnetic field, electric field and electromagnetic field, etc. Starting from the point of thermodynamics and taking the Gibbs adsorption as the model, the combination of energy axiom and the first law of thermodynamics was applied to boundary phase, and thus the theoretical expression for the volume of interface absorption under electric field as well as the mathematical relationship between surface tension and electric field intensity was obtained. In addition, according to the obtained theoretical expression, the volume of interface absorption of ethanol solution under different electric field intensities and concentrations was calculated. Moreover, the mechanism of interfacial adsorption was described from the perspective of thermodynamics and the influence of electric field on interfacial adsorption was explained reasonably, aiming to further discuss the influence of thermodynamic mechanism of interfacial adsorption on purifying air-conditioning engineering under intensification of electric field.

An easily reversible structural change underlies mechanisms enabling desert crust cyanobacteria to survive desiccation.

Science.gov (United States)

Bar-Eyal, Leeat; Eisenberg, Ido; Faust, Adam; Raanan, Hagai; Nevo, Reinat; Rappaport, Fabrice; Krieger-Liszkay, Anja; Sétif, Pierre; Thurotte, Adrien; Reich, Ziv; Kaplan, Aaron; Ohad, Itzhak; Paltiel, Yossi; Keren, Nir

2015-10-01

Biological desert sand crusts are the foundation of desert ecosystems, stabilizing the sands and allowing colonization by higher order organisms. The first colonizers of the desert sands are cyanobacteria. Facing the harsh conditions of the desert, these organisms must withstand frequent desiccation-hydration cycles, combined with high light intensities. Here, we characterize structural and functional modifications to the photosynthetic apparatus that enable a cyanobacterium, Leptolyngbya sp., to thrive under these conditions. Using multiple in vivo spectroscopic and imaging techniques, we identified two complementary mechanisms for dissipating absorbed energy in the desiccated state. The first mechanism involves the reorganization of the phycobilisome antenna system, increasing excitonic coupling between antenna components. This provides better energy dissipation in the antenna rather than directed exciton transfer to the reaction center. The second mechanism is driven by constriction of the thylakoid lumen which limits diffusion of plastocyanin to P700. The accumulation of P700(+) not only prevents light-induced charge separation but also efficiently quenches excitation energy. These protection mechanisms employ existing components of the photosynthetic apparatus, forming two distinct functional modes. Small changes in the structure of the thylakoid membranes are sufficient for quenching of all absorbed energy in the desiccated state, protecting the photosynthetic apparatus from photoinhibitory damage. These changes can be easily reversed upon rehydration, returning the system to its high photosynthetic quantum efficiency. Copyright © 2015 Elsevier B.V. All rights reserved.

32 CFR 887.7 - Persons separated under other than honorable conditions (undesirable or bad conduct) or...

Science.gov (United States)

2010-07-01

... 32 National Defense 6 2010-07-01 2010-07-01 false Persons separated under other than honorable conditions (undesirable or bad conduct) or dishonorable discharge. 887.7 Section 887.7 National Defense... honorable conditions (undesirable or bad conduct) or dishonorable discharge. Those persons whose character...

Amount of fear extinction changes its underlying mechanisms.

Science.gov (United States)

An, Bobae; Kim, Jihye; Park, Kyungjoon; Lee, Sukwon; Song, Sukwoon; Choi, Sukwoo

2017-07-03

There has been a longstanding debate on whether original fear memory is inhibited or erased after extinction. One possibility that reconciles this uncertainty is that the inhibition and erasure mechanisms are engaged in different phases (early or late) of extinction. In this study, using single-session extinction training and its repetition (multiple-session extinction training), we investigated the inhibition and erasure mechanisms in the prefrontal cortex and amygdala of rats, where neural circuits underlying extinction reside. The inhibition mechanism was prevalent with single-session extinction training but faded when single-session extinction training was repeated. In contrast, the erasure mechanism became prevalent when single-session extinction training was repeated. Moreover, ablating the intercalated neurons of amygdala, which are responsible for maintaining extinction-induced inhibition, was no longer effective in multiple-session extinction training. We propose that the inhibition mechanism operates primarily in the early phase of extinction training, and the erasure mechanism takes over after that.

Disaggregation and separation dynamics of magnetic particles in a microfluidic flow under an alternating gradient magnetic field

Science.gov (United States)

Cao, Quanliang; Li, Zhenhao; Wang, Zhen; Qi, Fan; Han, Xiaotao

2018-05-01

How to prevent particle aggregation in the magnetic separation process is of great importance for high-purity separation, while it is a challenging issue in practice. In this work, we report a novel method to solve this problem for improving the selectivity of size-based separation by use of a gradient alternating magnetic field. The specially designed magnetic field is capable of dynamically adjusting the magnetic field direction without changing the direction of magnetic gradient force acting on the particles. Using direct numerical simulations, we show that particles within a certain center-to-center distance are inseparable under a gradient static magnetic field since they are easy aggregated and then start moving together. By contrast, it has been demonstrated that alternating repulsive and attractive interaction forces between particles can be generated to avoid the formation of aggregations when the alternating gradient magnetic field with a given alternating frequency is applied, enabling these particles to be continuously separated based on size-dependent properties. The proposed magnetic separation method and simulation results have the significance for fundamental understanding of particle dynamic behavior and improving the separation efficiency.

Rotational particle separator: A new method for separating fine particles and mist from gases

NARCIS (Netherlands)

Brouwers, J.J.H.

1996-01-01

An account is given of the patented technique of the rotational particle separator for separating solid and liquid particles of diameter 0.1 µm and larger from gases. Attention is focused on the working principle, fluid mechanical constraints, particle design, separation performance, power

Rotational particle separator: A new method for separating fine particles and mists from gases

NARCIS (Netherlands)

Brouwers, J.J.H.

1996-01-01

An account is given of the patented technique of the rotational particle separator for separating solid and liquid particles of diameter 0.1 µm and larger from gases. Attention is focussed on the working principle, fluid mechanical constraints, practical designs, separation performance, power

Out-of-pile test of the crud separator system. (I)

International Nuclear Information System (INIS)

Takasaki, Akito; Iimura, Katsumichi; Tanaka, Isao

1991-01-01

The JMTR Project has been developing the crud separator system since 1981, and the advanced system has been fabricated for the in-pile test to be performed in the HBWR (Norway). The crud separator system removes magnetized crud circulating in a primary circuit by the permanent magnet assembly surrounded inside and outside of the separator vessel. Before the in-pile test, out-of-pile test was carried out in the JMTR Project under the condition of atmospheric pressure and room temperature, and the simplified theoretical analysis for crud separation mechanism was also carried out. The out-of-pile test results suggested that separation factor increased with increasing magnetic susceptibility of crud and crud particle diameter, and decreased with increasing flow rate. These results were in good agreement with the theoretical analysis. The test results also showed that the crud size enlarger was effective in lower separation factor region, which related to lower magnetic susceptibility of crud, smaller crud diameter and higher flow rate. (author)

Control of a perturbed under-actuated mechanical system

KAUST Repository

Zayane, Chadia; Laleg-Kirati, Taous-Meriem; Chemori, Ahmed

2015-01-01

In this work, the trajectory tracking problem for an under-actuated mechanical system in presence of unknown input disturbances is addressed. The studied inertia wheel inverted pendulum falls in the class of non minimum phase systems. The proposed

Magnetically Enhanced Solid-Liquid Separation

Science.gov (United States)

Rey, C. M.; Keller, K.; Fuchs, B.

2005-07-01

DuPont is developing an entirely new method of solid-liquid filtration involving the use of magnetic fields and magnetic field gradients. The new hybrid process, entitled Magnetically Enhanced Solid-Liquid Separation (MESLS), is designed to improve the de-watering kinetics and reduce the residual moisture content of solid particulates mechanically separated from liquid slurries. Gravitation, pressure, temperature, centrifugation, and fluid dynamics have dictated traditional solid-liquid separation for the past 50 years. The introduction of an external field (i.e. the magnetic field) offers the promise to manipulate particle behavior in an entirely new manner, which leads to increased process efficiency. Traditional solid-liquid separation typically consists of two primary steps. The first is a mechanical step in which the solid particulate is separated from the liquid using e.g. gas pressure through a filter membrane, centrifugation, etc. The second step is a thermal drying process, which is required due to imperfect mechanical separation. The thermal drying process is over 100-200 times less energy efficient than the mechanical step. Since enormous volumes of materials are processed each year, more efficient mechanical solid-liquid separations can be leveraged into dramatic reductions in overall energy consumption by reducing downstream drying requirements have a tremendous impact on energy consumption. Using DuPont's MESLS process, initial test results showed four very important effects of the magnetic field on the solid-liquid filtration process: 1) reduction of the time to reach gas breakthrough, 2) less loss of solid into the filtrate, 3) reduction of the (solids) residual moisture content, and 4) acceleration of the de-watering kinetics. These test results and their potential impact on future commercial solid-liquid filtration is discussed. New applications can be found in mining, chemical and bioprocesses.

Exploration of mechanisms underlying the strain-rate-dependent mechanical property of single chondrocytes

Energy Technology Data Exchange (ETDEWEB)

Nguyen, Trung Dung; Gu, YuanTong, E-mail: yuantong.gu@qut.edu.au [School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology, Brisbane, Queensland (Australia)

2014-05-05

Based on the characterization by Atomic Force Microscopy, we report that the mechanical property of single chondrocytes has dependency on the strain-rates. By comparing the mechanical deformation responses and the Young's moduli of living and fixed chondrocytes at four different strain-rates, we explore the deformation mechanisms underlying this dependency property. We found that the strain-rate-dependent mechanical property of living cells is governed by both of the cellular cytoskeleton and the intracellular fluid when the fixed chondrocytes are mainly governed by their intracellular fluid, which is called the consolidation-dependent deformation behavior. Finally, we report that the porohyperelastic constitutive material model which can capture the consolidation-dependent behavior of both living and fixed chondrocytes is a potential candidature to study living cell biomechanics.

Studies of the underlying mechanisms for optical nonlinearities of blue phase liquid crystals (Presentation Recording)

Science.gov (United States)

Chen, Chun-Wei; Khoo, Iam Choon; Zhao, Shuo; Lin, Tsung-Hsien; Ho, Tsung-Jui

2015-10-01

We have investigated the mechanisms responsible for nonlinear optical processes occurring in azobenzene-doped blue phase liquid crystals (BPLC), which exhibit two thermodynamically stable BPs: BPI and BPII. In coherent two wave-mixing experiments, a slow (minutes) and a fast (few milliseconds) side diffractions are observed. The underlying mechanisms were disclosed by monitoring the dynamics of grating formation and relaxation as well as by some supplementary experiments. We found the photothermal indexing and dye/LC intermolecular torque leading to lattice distortion to be the dominant mechanisms for the observed nonlinear response in BPLC. Moreover, the response time of the nonlinear optical process varied with operating phase. The rise time of the thermal indexing process was in good agreement with our findings on the temperature dependence of BP refractive index: τ(ISO) > τ(BPI) > τ(BPII). The relaxation time of the torque-induced lattice distortion was analogue to its electrostriction counterpart: τ'(BPI) > τ'(BPII). In a separate experiment, lattice swelling with selective reflection of direction changed from green to red was also observed. This was attributable to the isomerization-induced change in cholesteric pitch, which directly affects the lattice spacing. The phenomenon was confirmed by measuring the optical rotatory power of the BPLC.

Formation of structural steady states in lamellar/sponge phase-separating fluids under shear flow

Science.gov (United States)

Panizza, P.; Courbin, L.; Cristobal, G.; Rouch, J.; Narayanan, T.

2003-05-01

We investigate the effect of shear flow on a lamellar-sponge phase-separating fluid when subjected to shear flow. We show the existence of two different steady states (droplets and ribbons structures) whose nature does not depend on the way to reach the two-phase unstable region of the phase diagram (temperature quench or stirring). The transition between ribbons and droplets is shear thickening and its nature strongly depends on what dynamical variable is imposed. If the stress is fixed, flow visualization shows the existence of shear bands at the transition, characteristic of coexistence in the cell between ribbons and droplets. In this shear-banding region, the viscosity oscillates. When the shear rate is fixed, no shear bands are observed. Instead, the transition exhibits a hysteretic behavior leading to a structural bi-stability of the phase-separating fluid under flow.

Movable shark scales act as a passive dynamic micro-roughness to control flow separation

International Nuclear Information System (INIS)

Lang, Amy W; Bradshaw, Michael T; Smith, Jonathon A; Wheelus, Jennifer N; Motta, Philip J; Habegger, Maria L; Hueter, Robert E

2014-01-01

Shark scales on fast-swimming sharks have been shown to be movable to angles in excess of 50°, and we hypothesize that this characteristic gives this shark skin a preferred flow direction. During the onset of separation, flow reversal is initiated close to the surface. However, the movable scales would be actuated by the reversed flow thereby causing a greater resistance to any further flow reversal and this mechanism would disrupt the process leading to eventual flow separation. Here we report for the first time experimental evidence of the separation control capability of real shark skin through water tunnel testing. Using skin samples from a shortfin mako Isurus oxyrinchus, we tested a pectoral fin and flank skin attached to a NACA 4412 hydrofoil and separation control was observed in the presence of movable shark scales under certain conditions in both cases. We hypothesize that the scales provide a passive, flow-actuated mechanism acting as a dynamic micro-roughness to control flow separation. (paper)

Robust and durable superhydrophobic cotton fabrics for oil/water separation.

Science.gov (United States)

Zhou, Xiaoyan; Zhang, Zhaozhu; Xu, Xianghui; Guo, Fang; Zhu, Xiaotao; Men, Xuehu; Ge, Bo

2013-08-14

By introducing the incorporation of polyaniline and fluorinated alkyl silane to the cotton fabric via a facile vapor phase deposition process, the fabric surface possessed superhydrophobicity with the water contact angle of 156° and superoleophilicity with the oil contact angle of 0°. The as-prepared fabric can be applied as effective materials for the separation of water and oil mixture with separation efficiency as high as 97.8%. Compared with other materials for oil/water separation, the reported process was simple, time-saving, and repeatable for at least 30 times. Moreover, the obtained fabric kept stable superhydrophobicity and high separation efficiency under extreme environment conditions of high temperature, high humidity, strong acidic or alkaline solutions, and mechanical forces. Therefore, this reported fabric has the advantages of scalable fabrication, high separation efficiency, stable recyclability, and excellent durability, exhibiting the strong potential for industrial production.

Deformation Mechanisms of Gum Metals Under Nanoindentation

Science.gov (United States)

Sankaran, Rohini Priya

defect structures to applied loading, we perform ex-situ nanoindentation. Nanoindentation is a convenient method as the plastic deformation is localized and probes a nominally defect free volume of the material. We subsequently characterize the defect structures in these alloys with both conventional TEM and advanced techniques such as HAADF HRSTEM and nanoprobe diffraction. These advanced techniques allow for a more thorough understanding of the observed deformation features. The main findings from this investigation are as follows. As expected we observe that a non-equilibrium phase, o, is present in the leaner beta-stabilized alloy, ST Ref-1. We do not find any direct evidence of secondary phases in STGM, and we find the beta phase in CWGM, along with lath microstructure with subgrain structure consisting of dislocation cell networks. Upon nanoindentation, we find twinning accompanied by beta nucleation on the twin boundary in ST Ref-1 samples. This result is consistent with previous findings and is reasonable considering the alloy is unstable with respect to beta transformation. We find deformation nanotwinning in cold worked gum metals under nanoindentation, which is initially surprising. We argue that when viewed as a nanocrystalline material, such a deformation mechanism is consistent with previous work, and furthermore, a deformation nanotwinned structure does not preclude an ideal shear mechanism from operating in the alloy. Lastly, we observe continuous lattice rotations in STGM under nanoindentation via nanoprobe diffraction. With this technique, for the first time we can demonstrate that the lattice rotations are truly continuous at the nanoscale. We can quantify this lattice rotation, and find that even though the rotation is large, it may be mediated by a reasonable geometrically necessary dislocation density, and note that similar rotations are typically observed in other materials under nanoindentation. HRSTEM and conventional TEM data confirm the

Steam separator uprating by elimination of capacity-limiting mechanisms

International Nuclear Information System (INIS)

Parkinson, J.R.; Pruster, W.P.; Kidwell, J.H.; Schneider, W.G.

1985-01-01

Advanced steam/water separation equipment for nuclear steam generator application is required for new equipment manufacture and also for retrofit. For new equipment applications, the desire for higher capacity is driven by competitiveness which requires maximum throughput in the most compact package. For retrofit applications, which have arisen due to the poor performance of some of the original equipment, the need is for high capacity separators which can fit into the existing pressure vessel envelope and not only correct the performance problem, but also allow for uprated plant output. This paper describes the development of such advanced steam separators

Isotopic separation

International Nuclear Information System (INIS)

Castle, P.M.

1979-01-01

This invention relates to molecular and atomic isotope separation and is particularly applicable to the separation of 235 U from other uranium isotopes including 238 U. In the method described a desired isotope is separated mechanically from an atomic or molecular beam formed from an isotope mixture utilising the isotropic recoil momenta resulting from selective excitation of the desired isotope species by radiation, followed by ionization or dissociation by radiation or electron attachment. By forming a matrix of UF 6 molecules in HBr molecules so as to collapse the V 3 vibrational mode of the UF 6 molecule the 235 UF 6 molecules are selectively excited to promote reduction of UF 6 molecules containing 235 U and facilitate separation. (UK)

Cell-Nonautonomous Mechanisms Underlying Cellular and Organismal Aging.

Science.gov (United States)

Medkour, Younes; Svistkova, Veronika; Titorenko, Vladimir I

2016-01-01

Cell-autonomous mechanisms underlying cellular and organismal aging in evolutionarily distant eukaryotes have been established; these mechanisms regulate longevity-defining processes within a single eukaryotic cell. Recent findings have provided valuable insight into cell-nonautonomous mechanisms modulating cellular and organismal aging in eukaryotes across phyla; these mechanisms involve a transmission of various longevity factors between different cells, tissues, and organisms. Herein, we review such cell-nonautonomous mechanisms of aging in eukaryotes. We discuss the following: (1) how low molecular weight transmissible longevity factors modulate aging and define longevity of cells in yeast populations cultured in liquid media or on solid surfaces, (2) how communications between proteostasis stress networks operating in neurons and nonneuronal somatic tissues define longevity of the nematode Caenorhabditis elegans by modulating the rates of aging in different tissues, and (3) how different bacterial species colonizing the gut lumen of C. elegans define nematode longevity by modulating the rate of organismal aging. Copyright © 2016. Published by Elsevier Inc.

Crack assessment of pipe under combined thermal and mechanical load

International Nuclear Information System (INIS)

Song, Tae Kwang; Kim, Yun Jae

2009-01-01

In this paper, J-integral and transient C(t)-integral, which were key parameters in low temperature and high temperature fracture mechanics, under combined thermal and mechanical load were estimated via 3-dimensional finite element analyses. Various type of thermal and mechanical load, material hardening were considered to decrease conservatism in existing solutions. As a results, V-factor and redistribution time for combined thermal and mechanical load were proposed to calculate J-integral and C(t)-integral, respectively.

Chromatographic separations of stereoisomers

Energy Technology Data Exchange (ETDEWEB)

Souter, R.W.

1985-01-01

This text covers both diastereomers and enantiomers; describes techniques for GC, HPLC, and other chromatographic methods; and tabulates results of various applications by both techniques and compound class. It provides current knowledge about separation mechanisms and interactions of asymmetric molecules, as well as experimental and commercial materials such as columns, instruments, and derivatization reagents. The contents also include stereoisomer separations by gas chromatography. Stereoisomer separations by high-performance liquid chromatography. Stereoisomer separations by other chromatographic techniques.

Organ-specific proteomics analysis for identification of response mechanism in soybean seedlings under flooding stress.

Science.gov (United States)

Khatoon, Amana; Rehman, Shafiq; Hiraga, Susumu; Makino, Takahiro; Komatsu, Setsuko

2012-10-22

Flooding is one of the severe environmental factors which impair growth and yield in soybean plant. To investigate the organ specific response mechanism of soybean under flooding stress, changes in protein species were analyzed using a proteomics approach. Two-day-old soybeans were subjected to flooding for 5 days. Proteins were extracted from root, hypocotyl and leaf, and separated by two-dimensional polyacrylamide gel electrophoresis. In root, hypocotyl and leaf, 51, 66 and 51 protein species were significantly changed, respectively, under flooding stress. In root, metabolism related proteins were increased; however these proteins were decreased in hypocotyl and leaf. In all 3 organs, cytoplasm localized proteins were decreased, and leaf chloroplastic proteins were also decreased. Isoflavone reductase was commonly decreased at protein level in all 3 organs; however, mRNA of isoflavone reductase gene was up-regulated in leaf under flooding stress. Biophoton emission was increased in all 3 organs under flooding stress. The up-regulation of isoflavone reductase gene at transcript level; while decreased abundance at protein level indicated that flooding stress affected the mRNA translation to proteins. These results suggest that concurrence in expression of isoflavone reductase gene at mRNA and protein level along with imbalance in other disease/defense and metabolism related proteins might lead to impaired growth of root, hypocotyl and leaf of soybean seedlings under flooding stress. Copyright © 2012 Elsevier B.V. All rights reserved.

Photocatalytic degradation of methylene blue on magnetically separable MgFe2O4 under visible light irradiation

KAUST Repository

Shahid, Muhammad

2013-05-01

A magnetically separable single-phase MgFe2O4 photocatalyst with a spinel crystal structure was synthesized by using the solid-state reaction method. The formation of spinel structure is confirmed by X-ray diffraction and Fourier transform infrared spectroscopy. The magnetic measurements showed that the photocatalyst material can be separated from water when an external magnetic field is added and redispersed into water solution after the external magnetic field is eliminated. It is one of the promising photocatalysts for waste water treatment. The photocatalytic activity of MgFe2O4 was investigated by using the photo-decomposition of methylene blue dye under visible light. The photoelectrochemical property of the MgFe2O4 was studied by measuring their photocurrent-potential behavior in 1 M NaOH electrolyte under AM 1.5100 mW cm-2 illumination. © 2013 Elsevier B.V. All rights reserved.

Study of mechanism of hydrogen diffusion in separation devices. Progress report for 1980-1983

International Nuclear Information System (INIS)

Lee, M.H.

1983-01-01

For the purpose of studying the mechanisms of hydrogen diffusion in separation devices e.g. transition-metal membranes, we have developed a microscopic dynamic model appropriate for describing the nonequilibrium statistical mechanics of hydrogen-in-a-metal. Using this model we have carried out a detailed analysis to obtain the autocorrelation function of density fluctuations in the model. Our model is built on the physical idea that, at low temperatures, spin clusters are the basic units or aggregates of transport. Our work can explain the reversed isotope effect in diffusion. We have also obtained an expression for the relative diffusivity, verifiable by experiments with tritium in metals. Our notion of spin clusters is novel. There is some evidence of their existence. The interstitial spin clusters are comparable to atomic and nuclear spin clusters, the only other natural spin clusters. Our demonstration of a long-time tail in the autocorrelation function is also novel. Diffusion can be anomalous if long time tails exist, a current topic in nonlinear behavior of fluids and solids. Our progress has been made possible by our development in the mathematical method of solving the generalized Langevin equation. This method is applicable to any time-dependent quantum many-body model. The underlying basis of this method is our discovery of a new orthogonalization process in Hilbert space, first since Gram and Schmidt over 100 years ago. Our process is simpler if Hilbert space is realized as is for all physical problems. To demonstrate the power and utility of our method we considered a well established model of metals, thereby discovering the existence of a low-frequency electronic mobility. This kind of intrinsic conductivity should exist in ensembles of all light particles, hence also relevant to hydrogen and its isotopes in metals

Carbon Dioxide Separation Using Thermally Optimized Membranes

Science.gov (United States)

Young, J. S.; Jorgensen, B. S.; Espinoza, B. F.; Weimer, M. W.; Jarvinen, G. D.; Greenberg, A.; Khare, V.; Orme, C. J.; Wertsching, A. K.; Peterson, E. S.; Hopkins, S. D.; Acquaviva, J.

2002-05-01

The purpose of this project is to develop polymeric-metallic membranes for carbon dioxide separations that operate under a broad range of industrially relevant conditions not accessible with present membrane units. The last decade has witnessed a dramatic increase in the use of polymer membranes as an effective, economic and flexible tool for many commercial gas separations including air separation, the recovery of hydrogen from nitrogen, carbon monoxide, and methane mixtures, and the removal of carbon dioxide from natural gas. In each of these applications, high fluxes and excellent selectivities have relied on glassy polymer membranes which separate gases based on both size and solubility differences. To date, however, this technology has focused on optimizing materials for near ambient conditions. The development of polymeric materials that achieve the important combination of high selectivity, high permeability, and mechanical stability at temperatures significantly above 25oC and pressures above 10 bar, respectively, has been largely ignored. Consequently, there is a compelling rationale for the exploration of a new realm of polymer membrane separations. Indeed, the development of high temperature polymeric-metallic composite membranes for carbon dioxide separation at temperatures of 100-450 oC and pressures of 10-150 bar would provide a pivotal contribution with both economic and environmental benefits. Progress to date includes the first ever fabrication of a polymeric-metallic membrane that is selective from room temperature to 370oC. This achievement represents the highest demonstrated operating temperature at which a polymeric based membrane has successfully functioned. Additionally, we have generated the first polybenzamidizole silicate molecular composites. Finally, we have developed a technique that has enabled the first-ever simultaneous measurements of gas permeation and membrane compaction at elevated temperatures. This technique provides a unique

Mechanism of crack initiation and crack growth under thermal and mechanical fatigue loading

Energy Technology Data Exchange (ETDEWEB)

Utz, S.; Soppa, E.; Silcher, H.; Kohler, C. [Stuttgart Univ. (Germany). Materials Testing Inst.

2013-07-01

The present contribution is focused on the experimental investigations and numerical simulations of the deformation behaviour and crack development in the austenitic stainless steel X6CrNiNb18-10 under thermal and mechanical cyclic loading in HCF and LCF regimes. The main objective of this research is the understanding of the basic mechanisms of fatigue damage and the development of simulation methods, which can be applied further in safety evaluations of nuclear power plant components. In this context the modelling of crack initiation and crack growth inside the material structure induced by varying thermal or mechanical loads are of particular interest. The mechanisms of crack initiation depend among other things on the type of loading, microstructure, material properties and temperature. The Nb-stabilized austenitic stainless steel in the solution-annealed condition was chosen for the investigations. Experiments with two kinds of cyclic loading - pure thermal and pure mechanical - were carried out and simulated. The fatigue behaviour of the steel X6CrNiNb18-10 under thermal loading was studied within the framework of the joint research project [4]. Interrupted thermal cyclic tests in the temperature range of 150 C to 300 C combined with non-destructive residual stress measurements (XRD) and various microscopic investigations, e.g. in SEM (Scanning Electron Microscope), were used to study the effects of thermal cyclic loading on the material. This thermal cyclic loading leads to thermal induced stresses and strains. As a result intrusions and extrusions appear inside the grains (at the surface), at which microcracks arise and evolve to a dominant crack. Finally, these microcracks cause a continuous and significant decrease of residual stresses. The fatigue behaviour of the steel X6CrNiNb18-10 under mechanical loading at room temperature was studied within the framework of the research project [5], [8]. With a combination of interrupted LCF tests and EBSD

Mechanism of crack initiation and crack growth under thermal and mechanical fatigue loading

International Nuclear Information System (INIS)

Utz, S.; Soppa, E.; Silcher, H.; Kohler, C.

2013-01-01

The present contribution is focused on the experimental investigations and numerical simulations of the deformation behaviour and crack development in the austenitic stainless steel X6CrNiNb18-10 under thermal and mechanical cyclic loading in HCF and LCF regimes. The main objective of this research is the understanding of the basic mechanisms of fatigue damage and the development of simulation methods, which can be applied further in safety evaluations of nuclear power plant components. In this context the modelling of crack initiation and crack growth inside the material structure induced by varying thermal or mechanical loads are of particular interest. The mechanisms of crack initiation depend among other things on the type of loading, microstructure, material properties and temperature. The Nb-stabilized austenitic stainless steel in the solution-annealed condition was chosen for the investigations. Experiments with two kinds of cyclic loading - pure thermal and pure mechanical - were carried out and simulated. The fatigue behaviour of the steel X6CrNiNb18-10 under thermal loading was studied within the framework of the joint research project [4]. Interrupted thermal cyclic tests in the temperature range of 150 C to 300 C combined with non-destructive residual stress measurements (XRD) and various microscopic investigations, e.g. in SEM (Scanning Electron Microscope), were used to study the effects of thermal cyclic loading on the material. This thermal cyclic loading leads to thermal induced stresses and strains. As a result intrusions and extrusions appear inside the grains (at the surface), at which microcracks arise and evolve to a dominant crack. Finally, these microcracks cause a continuous and significant decrease of residual stresses. The fatigue behaviour of the steel X6CrNiNb18-10 under mechanical loading at room temperature was studied within the framework of the research project [5], [8]. With a combination of interrupted LCF tests and EBSD

Nuclide separation modeling through reverse osmosis membranes in radioactive liquid waste

Directory of Open Access Journals (Sweden)

Byung-Sik Lee

2015-12-01

Full Text Available The aim of this work is to investigate the transport mechanism of radioactive nuclides through the reverse osmosis (RO membrane and to estimate its effectiveness for nuclide separation from radioactive liquid waste. An analytical model is developed to simulate the RO separation, and a series of experiments are set up to confirm its estimated separation behavior. The model is based on the extended Nernst–Plank equation, which handles the convective flux, diffusive flux, and electromigration flux under electroneutrality and zero electric current conditions. The distribution coefficient which arises due to ion interactions with the membrane material and the electric potential jump at the membrane interface are included as boundary conditions in solving the equation. A high Peclet approximation is adopted to simplify the calculation, but the effect of concentration polarization is included for a more accurate prediction of separation. Cobalt and cesium are specifically selected for the experiments in order to check the separation mechanism from liquid waste composed of various radioactive nuclides and nonradioactive substances, and the results are compared with the estimated cobalt and cesium rejections of the RO membrane using the model. Experimental and calculated results are shown to be in excellent agreement. The proposed model will be very useful for the prediction of separation behavior of various radioactive nuclides by the RO membrane.

Nuclide separation modeling through reverse osmosis membranes in radioactive liquid waste

Energy Technology Data Exchange (ETDEWEB)

Lee, Byung Sik [KEPCO Engineering and Construction, Gimcheon (Korea, Republic of)

2015-12-15

The aim of this work is to investigate the transport mechanism of radioactive nuclides through the reverse osmosis (RO) membrane and to estimate its effectiveness for nuclide separation from radioactive liquid waste. An analytical model is developed to simulate the RO separation, and a series of experiments are set up to confirm its estimated separation behavior. The model is based on the extended Nernst-Plank equation, which handles the convective flux, diffusive flux, and electromigration flux under electroneutrality and zero electric current conditions. The distribution coefficient which arises due to ion interactions with the membrane material and the electric potential jump at the membrane interface are included as boundary conditions in solving the equation. A high Peclet approximation is adopted to simplify the calculation, but the effect of concentration polarization is included for a more accurate prediction of separation. Cobalt and cesium are specifically selected for the experiments in order to check the separation mechanism from liquid waste composed of various radioactive nuclides and nonradioactive substances, and the results are compared with the estimated cobalt and cesium rejections of the RO membrane using the model. Experimental and calculated results are shown to be in excellent agreement. The proposed model will be very useful for the prediction of separation behavior of various radioactive nuclides by the RO membrane.

Decomposition Methods For a Piv Data Analysis with Application to a Boundary Layer Separation Dynamics

Directory of Open Access Journals (Sweden)

Václav URUBA

2010-12-01

Full Text Available Separation of the turbulent boundary layer (BL on a flat plate under adverse pressure gradient was studied experimentally using Time-Resolved PIV technique. The results of spatio-temporal analysis of flow-field in the separation zone are presented. For this purpose, the POD (Proper Orthogonal Decomposition and its extension BOD (Bi-Orthogonal Decomposition techniques are applied as well as dynamical approach based on POPs (Principal Oscillation Patterns method. The study contributes to understanding physical mechanisms of a boundary layer separation process. The acquired information could be used to improve strategies of a boundary layer separation control.

On the atomistic mechanisms of alkane (methane-pentane) separation by distillation: a molecular dynamics study.

Science.gov (United States)

Zahn, Dirk

2007-11-01

Insights into the liquid-vapor transformation of methane-pentane mixtures were obtained from transition path sampling molecular dynamics simulations. This case study of the boiling of non-azeotropic mixtures demonstrates an unprejudiced identification of the atomistic mechanisms of phase separation in the course of vaporization which form the basis of distillation processes. From our simulations we observe spontaneous segregation events in the liquid mixture to trigger vapor nucleation. The formation of vapor domains stabilizes and further promotes the separation process by preferential evaporation of methane molecules. While this discrimination holds for all mixtures of different composition studied, a full account of the boiling process requires a more complex picture. At low methane concentration the nucleation of the vapor domains includes both methane and pentane molecules. The pentane molecules, however, tend to form small aggregates and undergo rapid re-condensation within picoseconds to nanoseconds scales. Accordingly, two aspects of selectivity accounting for methane-pentane separation in the course of liquid-vapor transformations were made accessible to molecular dynamics simulations: spontaneous segregation in the liquid phase leading to selective vapor nucleation and growth favoring methane vaporization and selective re-condensation of pentane molecules.

Fracture mechanics of hydroxyapatite single crystals under geometric confinement.

Science.gov (United States)

Libonati, Flavia; Nair, Arun K; Vergani, Laura; Buehler, Markus J

2013-04-01

Geometric confinement to the nanoscale, a concept that refers to the characteristic dimensions of structural features of materials at this length scale, has been shown to control the mechanical behavior of many biological materials or their building blocks, and such effects have also been suggested to play a crucial role in enhancing the strength and toughness of bone. Here we study the effect of geometric confinement on the fracture mechanism of hydroxyapatite (HAP) crystals that form the mineralized phase in bone. We report a series of molecular simulations of HAP crystals with an edge crack on the (001) plane under tensile loading, and we systematically vary the sample height whilst keeping the sample and the crack length constant. We find that by decreasing the sample height the stress concentration at the tip of the crack disappears for samples with a height smaller than 4.15nm, below which the material shows a different failure mode characterized by a more ductile mechanism with much larger failure strains, and the strength approaching that of a flaw-less crystal. This study directly confirms an earlier suggestion of a flaw-tolerant state that appears under geometric confinement and may explain the mechanical stability of the reinforcing HAP platelets in bone. Copyright © 2012 Elsevier Ltd. All rights reserved.

Believing versus interacting: Behavioural and neural mechanisms underlying interpersonal coordination

DEFF Research Database (Denmark)

Konvalinka, Ivana; Bauer, Markus; Kilner, James

When two people engage in a bidirectional interaction with each other, they use both bottom-up sensorimotor mechanisms such as monitoring and adapting to the behaviour of the other, as well as top-down cognitive processes, modulating their beliefs and allowing them to make decisions. Most research...... in joint action has investigated only one of these mechanisms at a time – low-level processes underlying joint coordination, or high-level cognitive mechanisms that give insight into how people think about another. In real interactions, interplay between these two mechanisms modulates how we interact...

Development on the automatic separator of separation of residual powders from SF hulls

International Nuclear Information System (INIS)

Jung, Jae Hoo; Kim, Young Hwang; Kim, Ki Ho; Park, Byung Buk; Lee, Hyo Jik; Kim, Sung Hyun; Park, Hee Sung; Lee, Jong Kwang; Kim, Ho Dong

2009-12-01

At the previous process of auto hull separator, vol-oxidizer convert UO 2 pellets to U 3 O 8 powder, and in the next step, hulls and powders is collected into each part of two vessels. In order to enhance the recover rate, fine powders on the surface of hulls should be removed from hulls. Auto hulls separator for fine powders is a device which can separate fine powders from hulls. In order to design and manufacture this device, we analyzed fine powders which are remained on the surface of hulls for separation properties, and selected separation and operation methods. Also, the main mechanism is devised by using the design considerations. These main mechanism consists of rotation drum, parts feeder, hull conveyer, powders separator, air shower, and vessels. Design considerations for auto hulls separator as follows ; capacity : 100 kg HM/batch, rod-cut length : 50 mm, recovery rate for fine powders : 95 % and operation condition : over 12 hrs/batch. We considered connection methods of the vessel and high vacuum module which can join with the outlet of auto hulls separator. Also, by using the above results, we have manufactured auto hulls separator for fine powders, and conducted blank tests for operation condition. Here, hulls of 50 mm length for test are used with 20 kg HM/batch. We have conducted separation tests of 2 batches to collect fine powders with hulls of 10 kg HM/batch. Our goal of recovery rate was 95%, but in the test result, the recovery rate of fine powders on the surface of hulls was over 96 %

In Situ Observations of Thermoreversible Gelation and Phase Separation of Agarose and Methylcellulose Solutions under High Pressure.

Science.gov (United States)

Kometani, Noritsugu; Tanabe, Masahiro; Su, Lei; Yang, Kun; Nishinari, Katsuyoshi

2015-06-04

Thermoreversible sol-gel transitions of agarose and methylcellulose (MC) aqueous solutions on isobaric cooling or heating under high pressure up to 400 MPa have been investigated by in situ observations of optical transmittance and falling-ball experiments. For agarose, which undergoes the gelation on cooling, the application of pressure caused a gradual rise in the cloud-point temperature over the whole pressure range examined, which is almost consistent with the pressure dependence of gelling temperature estimated by falling-ball experiments, suggesting that agarose gel is stabilized by compression and that the gelation occurs nearly in parallel with phase separation under ambient and high-pressure conditions. For MC, which undergoes the gelation on heating, the cloud-point temperature showed a slight rise with an initial elevation of pressure up to ∼150 MPa, whereas it showed a marked depression above 200 MPa. In contrast, the gelling temperature of MC, which is nearly identical to the cloud-point temperature at ambient pressure, showed a monotonous rise with increasing pressure up to 350 MPa, which means that MC undergoes phase separation prior to gelation on heating under high pressure above 200 MPa. Similar results were obtained for the melting process of MC gel on cooling. The unique behavior of the sol-gel transition of MC under high pressure has been interpreted in terms of the destruction of hydrophobic hydration by compression.

Origin of Reversible Photoinduced Phase Separation in Hybrid Perovskites

Science.gov (United States)

Bischak, Connor G.; Hetherington, Craig L.; Wu, Hao; Aloni, Shaul; Ogletree, D. Frank; Limmer, David T.; Ginsberg, Naomi S.

2017-02-01

Nonequilibrium processes occurring in functional materials can significantly impact device efficiencies and are often difficult to characterize due to the broad range of length and time scales involved. In particular, mixed halide hybrid perovskites are promising for optoelectronics, yet the halides reversibly phase separate when photo-excited, significantly altering device performance. By combining nanoscale imaging and multiscale modeling, we elucidate the mechanism underlying this phenomenon, demonstrating that local strain induced by photo-generated polarons promotes halide phase separation and leads to nucleation of light-stabilized iodide-rich clusters. This effect relies on the unique electromechanical properties of hybrid materials, characteristic of neither their organic nor inorganic constituents alone. Exploiting photo-induced phase separation and other nonequilibrium phenomena in hybrid materials, generally, could enable new opportunities for expanding the functional applications in sensing, photoswitching, optical memory, and energy storage.

Mechanical behavior of silicon carbide nanoparticles under uniaxial compression

Energy Technology Data Exchange (ETDEWEB)

He, Qiuxiang; Fei, Jing; Tang, Chao; Zhong, Jianxin; Meng, Lijun, E-mail: ljmeng@xtu.edu.cn [Xiangtan University, Hunan Key Laboratory for Micro-Nano Energy Materials and Devices, Faculty of School of Physics and Optoelectronics (China)

2016-03-15

The mechanical behavior of SiC nanoparticles under uniaxial compression was investigated using an atomic-level compression simulation technique. The results revealed that the mechanical deformation of SiC nanocrystals is highly dependent on compression orientation, particle size, and temperature. A structural transformation from the original zinc-blende to a rock-salt phase is identified for SiC nanoparticles compressed along the [001] direction at low temperature. However, the rock-salt phase is not observed for SiC nanoparticles compressed along the [110] and [111] directions irrespective of size and temperature. The high-pressure-generated rock-salt phase strongly affects the mechanical behavior of the nanoparticles, including their hardness and deformation process. The hardness of [001]-compressed nanoparticles decreases monotonically as their size increases, different from that of [110] and [111]-compressed nanoparticles, which reaches a maximal value at a critical size and then decreases. Additionally, a temperature-dependent mechanical response was observed for all simulated SiC nanoparticles regardless of compression orientation and size. Interestingly, the hardness of SiC nanocrystals with a diameter of 8 nm compressed in [001]-orientation undergoes a steep decrease at 0.1–200 K and then a gradual decline from 250 to 1500 K. This trend can be attributed to different deformation mechanisms related to phase transformation and dislocations. Our results will be useful for practical applications of SiC nanoparticles under high pressure.

Post-separation families: Residential arrangements and everyday life of separated parents and their children

NARCIS (Netherlands)

Bakker, W.

2015-01-01

This dissertation is about post-separation families, their residential arrangements and the organization and practising of their everyday post-separation (family) life. Divorce and separation are common life events in most Western countries. In the Netherlands, 30% of all children under age 18

Process, including PSA and membrane separation, for separating hydrogen from hydrocarbons

Science.gov (United States)

Baker, Richard W.; Lokhandwala, Kaaeid A.; He, Zhenjie; Pinnau, Ingo

2001-01-01

An improved process for separating hydrogen from hydrocarbons. The process includes a pressure swing adsorption step, a compression/cooling step and a membrane separation step. The membrane step relies on achieving a methane/hydrogen selectivity of at least about 2.5 under the conditions of the process.

Nonlinear Mechanics of MEMS Rectangular Microplates under Electrostatic Actuation

KAUST Repository

Saghir, Shahid

2016-01-01

The first objective of the dissertation is to develop a suitable reduced order model capable of investigating the nonlinear mechanical behavior of von-Karman plates under electrostatic actuation. The second objective is to investigate the nonlinear

Mechanical separation process for decladding of LWR fuel elements

International Nuclear Information System (INIS)

Koch, R.

1984-10-01

A comparison of the advantages and disadvantages of known methods of decladding led to cavitation erosion being used as a decladding mechanism. This process attacks not the jacket of the fuel rod but the fuel itself. Cavitation erosion is the consequence of imploding vapour bubbles entailing dynamic stress of a high frequency and high amplitude. The separation effect is due to the different material properties. Ductile materials as a rule are much more resistant to dynamic stress than brittle materials. Systematic experiments at varying pressures, volume flow, nozzle geometries and distances between nozzle and sample led to optimized parameters. There was a conspicuous rise in the relations pressure to depth of erosion and volume flow to depth of erosion. This considered, p=700 bar and d=1.6 mm were found to be useful parameters. The relation of the distance from nozzle to sample and the erosion obtained also has an optimum at s=50 mm. This distance can be shortened in the course of the operation. A great entrance angle combined with a nozzle outlet channel of the length l=1/2 D improves the erosion result considerably. The attack of the cavitating water jet on the jacket of the fuel rod causes a weight loss of [de

Peripheral Receptor Mechanisms Underlying Orofacial Muscle Pain and Hyperalgesia

Science.gov (United States)

Saloman, Jami L.

Musculoskeletal pain conditions, particularly those associated with temporomandibular joint and muscle disorders (TMD) are severely debilitating and affect approximately 12% of the population. Identifying peripheral nociceptive mechanisms underlying mechanical hyperalgesia, a prominent feature of persistent muscle pain, could contribute to the development of new treatment strategies for the management of TMD and other muscle pain conditions. This study provides evidence of functional interactions between ligand-gated channels, P2X3 and TRPV1/TRPA1, in trigeminal sensory neurons, and proposes that these interactions underlie the development of mechanical hyperalgesia. In the masseter muscle, direct P2X3 activation, via the selective agonist αβmeATP, induced a dose- and time-dependent hyperalgesia. Importantly, the αβmeATP-induced hyperalgesia was prevented by pretreatment of the muscle with a TRPV1 antagonist, AMG9810, or the TRPA1 antagonist, AP18. P2X3 was co-expressed with both TRPV1 and TRPA1 in masseter muscle afferents confirming the possibility for intracellular interactions. Moreover, in a subpopulation of P2X3 /TRPV1 positive neurons, capsaicin-induced Ca2+ transients were significantly potentiated following P2X3 activation. Inhibition of Ca2+-dependent kinases, PKC and CaMKII, prevented P2X3-mechanical hyperalgesia whereas blockade of Ca2+-independent PKA did not. Finally, activation of P2X3 induced phosphorylation of serine, but not threonine, residues in TRPV1 in trigeminal sensory neurons. Significant phosphorylation was observed at 15 minutes, the time point at which behavioral hyperalgesia was prominent. Similar data were obtained regarding another nonselective cation channel, the NMDA receptor (NMDAR). Our data propose P2X3 and NMDARs interact with TRPV1 in a facilitatory manner, which could contribute to the peripheral sensitization underlying masseter hyperalgesia. This study offers novel mechanisms by which individual pro-nociceptive ligand

On the role of local charge carrier mobility in the charge separation mechanism of organic photovoltaics.

Science.gov (United States)

Yoshikawa, Saya; Saeki, Akinori; Saito, Masahiko; Osaka, Itaru; Seki, Shu

2015-07-21

Although the charge separation (CS) and transport processes that compete with geminate and non-geminate recombination are commonly regarded as the governing factors of organic photovoltaic (OPV) efficiency, the details of the CS mechanism remain largely unexplored. Here we provide a systematic investigation on the role of local charge carrier mobility in bulk heterojunction films of ten different low-bandgap polymers and polythiophene analogues blended with methanofullerene (PCBM). By correlating with the OPV performances, we demonstrated that the local mobility of the blend measured by time-resolved microwave conductivity is more important for the OPV output than those of the pure polymers. Furthermore, the results revealed two separate trends for crystalline and semi-crystalline polymers. This work offers guidance in the design of high-performance organic solar cells.

Underlying mechanisms of improving physical activity behavior after rehabilitation

NARCIS (Netherlands)

van der Ploeg, H.P.; Streppel, K.R.; van der Beek, A.J.; van der Woude, L.H.V.; van Harten, W.H.; van Mechelen, W.

2008-01-01

Background: Regular physical activity is beneficial for the health and functioning of people with a disability. Effective components of successful physical activity promotion interventions should be identified and disseminated. Purpose: To study the underlying mechanisms of the combined sport

Underlying Mechanisms of Improving Physical Activity Behavior after Rehabilitation

NARCIS (Netherlands)

van der Ploeg, Hidde P.; Streppel, Kitty R.M.; van der Beek, Allard J.; Woude, Luc H.V.; van Harten, Willem H.; Vollenbroek-Hutten, Miriam Marie Rosé; van Mechelen, Willem

2008-01-01

Background: Regular physical activity is beneficial for the health and functioning of people with a disability. Effective components of successful physical activity promotion interventions should be identified and disseminated. Purpose: To study the underlying mechanisms of the combined sport

Dual-band frequency selective surface with large band separation and stable performance

International Nuclear Information System (INIS)

Zhou Hang; Qu Shao-Bo; Lin Bao-Qin; Wang Jia-Fu; Ma Hua; Zhang Jie-Qiu; Peng Wei-Dong; Bai Peng; Wang Xu-Hua; Xu Zhuo

2012-01-01

A new technique of designing a dual-band frequency selective surface with large band separation is presented. This technique is based on a delicately designed topology of L- and Ku-band microwave filters. The two band-pass responses are generated by a capacitively-loaded square-loop frequency selective surface and an aperture-coupled frequency selective surface, respectively. A Faraday cage is located between the two frequency selective surface structures to eliminate undesired couplings. Based on this technique, a dual-band frequency selective surface with large band separation is designed, which possesses large band separation, high selectivity, and stable performance under various incident angles and different polarizations. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

On the dynamic mechanical property and deformation mechanism of as-extruded Mg-Sn-Ca alloys under tension

International Nuclear Information System (INIS)

Huang, Qiuyan; Pan, Hucheng; Tang, Aitao; Ren, Yuping; Song, Bo; Qin, Gaowu; Zhang, Mingxing; Pan, Fusheng

2016-01-01

To further understand the deformation mechanism of magnesium alloys and expand their applications under dynamic conditions, the newly developed Mg-2Sn-1Ca alloy (TX21) is selected as the representative sample and tested under wide loading rate ranging from quasi-static to dynamic level (10"−"3–500/s). Both ultimate tensile strength and elongation of the as-extruded TX21 alloys increase with strain rate. Although twinning is accompanied due to the enhanced activity at higher strain rate, the preferential activation of dislocations is readily clarified and confirmed as the dominant deformation modes. Active interactions of pyramidal dislocations result in the higher strain hardening ability and could be correlated to the obviously positive strain-rate sensitivity for mechanical properties. Moreover, it is observed that the larger grain size and higher content of solute atoms dissolved in matrix would lead to the more active dislocations and twinning formations. The present results would provide insight into further understanding the deformation mechanism under dynamic rate loading and designing Mg alloy suitable for impact conditions.

On the dynamic mechanical property and deformation mechanism of as-extruded Mg-Sn-Ca alloys under tension

Energy Technology Data Exchange (ETDEWEB)

Huang, Qiuyan [National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Pan, Hucheng [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Tang, Aitao, E-mail: tat@cqu.edu.cn [National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China); Ren, Yuping [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Song, Bo [Faculty of Materials and Energy, Southwest University, Chongqing 400715 (China); Qin, Gaowu, E-mail: qingw@smm.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819 (China); Zhang, Mingxing [School of Mechanical and Mining Engineering, University of Queensland, St Lucia, QLD 4072 (Australia); Pan, Fusheng [National Engineering Research Center for Magnesium Alloys, Chongqing University, Chongqing 400044 (China)

2016-05-10

To further understand the deformation mechanism of magnesium alloys and expand their applications under dynamic conditions, the newly developed Mg-2Sn-1Ca alloy (TX21) is selected as the representative sample and tested under wide loading rate ranging from quasi-static to dynamic level (10{sup −3}–500/s). Both ultimate tensile strength and elongation of the as-extruded TX21 alloys increase with strain rate. Although twinning is accompanied due to the enhanced activity at higher strain rate, the preferential activation of dislocations is readily clarified and confirmed as the dominant deformation modes. Active interactions of pyramidal dislocations result in the higher strain hardening ability and could be correlated to the obviously positive strain-rate sensitivity for mechanical properties. Moreover, it is observed that the larger grain size and higher content of solute atoms dissolved in matrix would lead to the more active dislocations and twinning formations. The present results would provide insight into further understanding the deformation mechanism under dynamic rate loading and designing Mg alloy suitable for impact conditions.

Animal behavior models of the mechanisms underlying antipsychotic atypicality.

NARCIS (Netherlands)

Geyer, M.A.; Ellenbroek, B.A.

2003-01-01

This review describes the animal behavior models that provide insight into the mechanisms underlying the critical differences between the actions of typical vs. atypical antipsychotic drugs. Although many of these models are capable of differentiating between antipsychotic and other psychotropic

Molecular mechanisms underlying the emergence of bacterial pathogens: an ecological perspective.

Science.gov (United States)

Bartoli, Claudia; Roux, Fabrice; Lamichhane, Jay Ram

2016-02-01

The rapid emergence of new bacterial diseases negatively affects both human health and agricultural productivity. Although the molecular mechanisms underlying these disease emergences are shared between human- and plant-pathogenic bacteria, not much effort has been made to date to understand disease emergences caused by plant-pathogenic bacteria. In particular, there is a paucity of information in the literature on the role of environmental habitats in which plant-pathogenic bacteria evolve and on the stress factors to which these microbes are unceasingly exposed. In this microreview, we focus on three molecular mechanisms underlying pathogenicity in bacteria, namely mutations, genomic rearrangements and the acquisition of new DNA sequences through horizontal gene transfer (HGT). We briefly discuss the role of these mechanisms in bacterial disease emergence and elucidate how the environment can influence the occurrence and regulation of these molecular mechanisms by directly impacting disease emergence. The understanding of such molecular evolutionary mechanisms and their environmental drivers will represent an important step towards predicting bacterial disease emergence and developing sustainable management strategies for crops. © 2015 BSPP AND JOHN WILEY & SONS LTD.

Pentiptycene-based polyurethane with enhanced mechanical properties and CO2-plasticization resistance for thin film gas separation membranes.

Science.gov (United States)

Pournaghshband Isfahani, Ali; Sadeghi, Morteza; Wakimoto, Kazuki; Shrestha, Binod Babu; Bagheri, Rouhollah; Sivaniah, Easan; Ghalei, Behnam

2018-04-30

Development of thin film composite (TFC) membranes offers an opportunity to achieve the permeability/selectivity requirements for optimum CO2 separation performance. However, the durability and performance of thin film gas separation membranes are mostly challenged by weak mechanical properties and high CO2 plasticization. Here, we designed new polyurethane (PU) structures with bulky aromatic chain extenders that afford preferred mechanical properties for ultra-thin film formation. An improvement of about 1500% in Young's modulus and 600% in hardness was observed for pentiptycene-based PUs compared to typical PU membranes. Single (CO2, H2, CH4, and N2) and mixed (CO2/N2 and CO2/CH4) gas permeability tests were performed on the PU membranes. The resulting TFC membranes showed a high CO2 permeance up to 1400 GPU (10-6 cm3(STP) cm-2s-1 cmHg-1) and the CO2/N2 and CO2/H2 selectivities of about 22 and 2.1, respectively. The enhanced mechanical properties of pentiptycene-based PUs results in high performance thin membranes with the similar selectivity of the bulk polymer. The thin film membranes prepared from pentiptycene-based PUs also showed a two-fold enhanced plasticization resistance compared to non-pentiptycene containing PU membranes.

Mechanically durable underwater superoleophobic surfaces based on hydrophilic bulk metals for oil/water separation

Science.gov (United States)

Yu, Huadong; Lian, Zhongxu; Xu, Jinkai; Wan, Yanling; Wang, Zuobin; Li, Yiquan; Yu, Zhanjiang; Weng, Zhankun

2018-04-01

Despite the success of previous methods for fabricating underwater superoleophobic surfaces, most of the surfaces based on soft materials are prone to collapse and deformation due to their mechanically fragile nature, and they fail to perform their designed functions after the surface materials are damaged in water. In this work, the nanosecond laser-induced oxide coatings on hydrophilic bulk metals are reported which overcomes the limitation and shows the robust underwater superoleophobicity to a mechanical challenge encountered by surfaces deployed in water environment. The results show that the surface materials have the advantage that the underwater superoleophobicity is still preserved after the surfaces are scratched by knife or sandpaper and even completely destroyed because of the hydrophilic property of damaged materials in water. It is important that the results provide a guide for the design of durable underwater superoleophobic surfaces, and the development of superoleophobic materials in many potential applications such as the oil-repellent and the oil/water separation. Additionally, the nanosecond laser technology is simple, cost-effective and suitable for the large-area and mass fabrication of mechanically durable underwater superoleophobic metal materials.

Using High Performance Computing to Examine the Processes of Neurogenesis Underlying Pattern Separation/Completion of Episodic Information.

Energy Technology Data Exchange (ETDEWEB)

Aimone, James Bradley [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Betty, Rita [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-03-01

Using High Performance Computing to Examine the Processes of Neurogenesis Underlying Pattern Separation/Completion of Episodic Information - Sandia researchers developed novel methods and metrics for studying the computational function of neurogenesis, thus generating substantial impact to the neuroscience and neural computing communities. This work could benefit applications in machine learning and other analysis activities.

Electrospun polyacrylonitrile/polyurethane composite nanofibrous separator with electrochemical performance for high power lithium ion batteries

Energy Technology Data Exchange (ETDEWEB)

Zainab, Ghazala [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Wang, Xianfeng, E-mail: wxf@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Key Laboratory of High Performance Fibers & Products, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Nanofibers Research Center, Modern Textile Institute, Donghua University, Shanghai 200051 (China); Yu, Jianyong [Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Key Laboratory of High Performance Fibers & Products, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Nanofibers Research Center, Modern Textile Institute, Donghua University, Shanghai 200051 (China); Zhai, Yunyun; Ahmed Babar, Aijaz; Xiao, Ke [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Ding, Bin, E-mail: binding@dhu.edu.cn [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Key Laboratory of Textile Science & Technology, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Key Laboratory of High Performance Fibers & Products, Ministry of Education, College of Textiles, Donghua University, Shanghai 201620 (China); Nanofibers Research Center, Modern Textile Institute, Donghua University, Shanghai 200051 (China)

2016-10-01

Lithium ion batteries (LIBs) for high performance require separators with auspicious reliability and safety. Keeping LIBs reliability and safety in view, microporous polyacrylonitrile (PAN)/polyurethane (PU) nonwoven composite separator have been developed by electrospinning technique. The physical, electrochemical and thermal properties of the PAN/PU separator were characterized. Improved ionic conductivity up to 2.07 S cm{sup −1}, high mechanical strength (10.38 MPa) and good anodic stability up to 5.10 V are key outcomes of resultant membranes. Additionally, high thermal stability displaying only 4% dimensional change after 0.5 h long exposure to 170 °C in an oven, which could be valuable addition towards the safety of LIBs. Comparing to commercialized polypropylene based separators, resulting membranes offered improved internal short-circuit protection function, offering better rate capability and enhanced capacity retention under same observation conditions. These fascinating characteristics endow these renewable composite nonwovens as promising separators for high power LIBs battery. - Highlights: • The PAN/PU based separators were prepared by multi-needle electrospinning technique. • The electrospun separators displays good mechanical properties and thermal stability. • These separators exhibit good wettability with liquid electrolyte, high ion conductivity and internal short-circuit protection. • Nanofibrous composite nonwoven possesses stable cyclic performance which give rise to acceptable battery performances.

The Influence of Drift Gas Composition on the Separation Mechanism in Traveling Wave Ion Mobility Spectrometry: Insight from Electrodynamic Simulations.

Science.gov (United States)

May, Jody C; McLean, John A

2003-06-01

The influence of three different drift gases (helium, nitrogen, and argon) on the separation mechanism in traveling wave ion mobility spectrometry is explored through ion trajectory simulations which include considerations for ion diffusion based on kinetic theory and the electrodynamic traveling wave potential. The model developed for this work is an accurate depiction of a second-generation commercial traveling wave instrument. Three ion systems (cocaine, MDMA, and amphetamine) whose reduced mobility values have previously been measured in different drift gases are represented in the simulation model. The simulation results presented here provide a fundamental understanding of the separation mechanism in traveling wave, which is characterized by three regions of ion motion: (1) ions surfing on a single wave, (2) ions exhibiting intermittent roll-over onto subsequent waves, and (3) ions experiencing a steady state roll-over which repeats every few wave cycles. These regions of ion motion are accessed through changes in the gas pressure, wave amplitude, and wave velocity. Resolving power values extracted from simulated arrival times suggest that momentum transfer in helium gas is generally insufficient to access regions (2) and (3) where ion mobility separations occur. Ion mobility separations by traveling wave are predicted to be effectual for both nitrogen and argon, with slightly lower resolving power values observed for argon as a result of band-broadening due to collisional scattering. For the simulation conditions studied here, the resolving power in traveling wave plateaus between regions (2) and (3), with further increases in wave velocity contributing only minor improvements in separations.

Film thickness dependence of phase separation and dewetting behaviors in PMMA/SAN blend films.

Science.gov (United States)

You, Jichun; Liao, Yonggui; Men, Yongfeng; Shi, Tongfei; An, Lijia

2010-09-21

Film thickness dependence of complex behaviors coupled by phase separation and dewetting in blend [poly(methyl methacrylate) (PMMA) and poly(styrene-ran-acrylonitrile) (SAN)] films on silicon oxide substrate at 175 °C was investigated by grazing incidence ultrasmall-angle X-ray scattering (GIUSAX) and in situ atomic force microscopy (AFM). It was found that the dewetting pathway was under the control of the parameter U(q0)/E, which described the initial amplitude of the surface undulation and original thickness of film, respectively. Furthermore, our results showed that interplay between phase separation and dewetting depended crucially on film thickness. Three mechanisms including dewetting-phase separation/wetting, dewetting/wetting-phase separation, and phase separation/wetting-pseudodewetting were discussed in detail. In conclusion, it is relative rates of phase separation and dewetting that dominate the interplay between them.

PBI treated polypropylene battery separator

Science.gov (United States)

Veryzwyvelt, S. A.

1981-01-01

A generalized procedure for fabricating the separator is described. Some of the desired properties considered in fabricating the separator material for nickel-cadmium cells were good mechanical strength, good chemical stability, good wettability to the electrolyte, high electrolyte retention, and gas passage.

15 N separation in the Nitrox system under pressure

International Nuclear Information System (INIS)

Axente, D.; Baldea, A.; Teaca, C.; Horga, R.; Abrudean, M.

1999-01-01

The basic isotope exchange reaction responsible for the separation of 15 N in Nitrox system is that between gaseous nitrogen oxides and aqueous nitric acid with single stage separation factor α = 1.055 for M.l -1 nitric acid, at 25 deg. C and atmospheric pressure. The rate of nitrogen isotope exchange between NO and HNO 3 has been measured as a function of nitric oxide pressure 0.1 - 0.4 MPa for 1 and 2 M.l -1 . It is concluded that 15 N/ 14 N exchange rate in NO-HNO 3 system has a linear dependence on NO pressure as indicated by rate measurements at different NO partial pressure and constant overall pressure, by adding helium in reactor. Using the rate law: R = [HNO 3 ] 2 [N 2 O 3 ] the 15 N/ 14 N exchange rates for nitric acid concentrations 1.5 - 10 M.l -1 were calculated. In order to know what happens in 15 N separation at higher pressure, when the isotopic transport between two phases is improved, a stainless steel laboratory experimental setup with 1000 mm long x 18 mm i,d. column, packed with triangular wire springs 1.8 x 1.8 x 0.2 mm was utilised. At 0.15 MPA and 2.36 ml.cm -2 . min -1 flow rate HETP was 7% smaller than at atmospheric pressure and 1.5 times smaller flow rate. HETP at 3.14 ml . cm -2 . min -1 flow rate and 0.18 MPa is practically equal with that obtained at atmospheric pressure and 2 times smaller flow rate. The operation of the 15 N separation setup at 0.18 MPa, instead of atmospheric pressure, will permit to double the 10 M.l -1 nitric acid flow rate and of 15 N production of the given column. (authors)

Regulation of Caenorhabditis elegans vitellogenesis by DAF-2/IIS through separable transcriptional and posttranscriptional mechanisms.

Science.gov (United States)

DePina, Ana S; Iser, Wendy B; Park, Sung-Soo; Maudsley, Stuart; Wilson, Mark A; Wolkow, Catherine A

2011-07-12

Evolutionary theories of aging propose that longevity evolves as a competition between reproduction and somatic maintenance for a finite pool of resources. Reproduction is thought to shorten lifespan by depleting resources from processes promoting somatic maintenance. Maternal yolk production, vitellogenesis, represents a significant maternal cost for reproduction and is suppressed under genetic and environmental conditions that extend lifespan. However, little is known about the pathways regulating vitellogenesis in response to prolongevity cues. In order to identify mechanisms that suppress vitellogenesis under prolongevity conditions, we studied factors regulating vitellogenesis in C. elegans nematodes. In C. elegans, vitellogenesis is depressed in the absence of insulin-like signaling (IIS). We found that the C. elegans daf-2/IIS pathway regulates vitellogenesis through two mechanisms. vit-2 transcript levels in daf-2 mutants were indirectly regulated through a germline-dependent signal, and could be rescued by introduction of daf-2(+) sperm. However, yolk protein (YP) levels in daf-2 mutants were also regulated by germline-independent posttranscriptional mechanisms. C. elegans vitellogenesis is regulated transcriptionally and posttranscriptionally in response to environmental and reproductive cues. The daf-2 pathway suppressed vitellogenesis through transcriptional mechanisms reflecting reproductive phenotypes, as well as distinct posttranscriptional mechanisms. This study reveals that pleiotropic effects of IIS pathway mutations can converge on a common downstream target, vitellogenesis, as a mechanism to modulate longevity.

Regulation of Caenorhabditis elegans vitellogenesis by DAF-2/IIS through separable transcriptional and posttranscriptional mechanisms

Directory of Open Access Journals (Sweden)

Wilson Mark A

2011-07-01

Full Text Available Abstract Background Evolutionary theories of aging propose that longevity evolves as a competition between reproduction and somatic maintenance for a finite pool of resources. Reproduction is thought to shorten lifespan by depleting resources from processes promoting somatic maintenance. Maternal yolk production, vitellogenesis, represents a significant maternal cost for reproduction and is suppressed under genetic and environmental conditions that extend lifespan. However, little is known about the pathways regulating vitellogenesis in response to prolongevity cues. Results In order to identify mechanisms that suppress vitellogenesis under prolongevity conditions, we studied factors regulating vitellogenesis in C. elegans nematodes. In C. elegans, vitellogenesis is depressed in the absence of insulin-like signaling (IIS. We found that the C. elegans daf-2/IIS pathway regulates vitellogenesis through two mechanisms. vit-2 transcript levels in daf-2 mutants were indirectly regulated through a germline-dependent signal, and could be rescued by introduction of daf-2(+ sperm. However, yolk protein (YP levels in daf-2 mutants were also regulated by germline-independent posttranscriptional mechanisms. Conclusions C. elegans vitellogenesis is regulated transcriptionally and posttranscriptionally in response to environmental and reproductive cues. The daf-2 pathway suppressed vitellogenesis through transcriptional mechanisms reflecting reproductive phenotypes, as well as distinct posttranscriptional mechanisms. This study reveals that pleiotropic effects of IIS pathway mutations can converge on a common downstream target, vitellogenesis, as a mechanism to modulate longevity.

Mechanisms underlying UV-induced immune suppression

International Nuclear Information System (INIS)

Ullrich, Stephen E.

2005-01-01

Skin cancer is the most prevalent form of human neoplasia. Estimates suggest that in excess of one million new cases of skin cancer will be diagnosed this year alone in the United States (www.cancer.org/statistics). Fortunately, because of their highly visible location, skin cancers are more rapidly diagnosed and more easily treated than other types of cancer. Be that as it may, approximately 10,000 Americans a year die from skin cancer. The cost of treating non-melanoma skin cancer is estimated to be in excess of US$ 650 million a year [J.G. Chen, A.B. Fleischer, E.D. Smith, C. Kancler, N.D. Goldman, P.M. Williford, S.R. Feldman, Cost of non-melanoma skin cancer treatment in the United States, Dermatol. Surg. 27 (2001) 1035-1038], and when melanoma is included, the estimated cost of treating skin cancer in the United States is estimated to rise to US$ 2.9 billion annually (www.cancer.org/statistics). Because the morbidity and mortality associated with skin cancer is a major public health problem, it is important to understand the mechanisms underlying skin cancer development. The primary cause of skin cancer is the ultraviolet (UV) radiation found in sunlight. In addition to its carcinogenic potential, UV radiation is also immune suppressive. In fact, data from studies with both experimental animals and biopsy proven skin cancer patients suggest that there is an association between the immune suppressive effects of UV radiation and its carcinogenic potential. The focus of this manuscript will be to review the mechanisms underlying the induction of immune suppression following UV exposure. Particular attention will be directed to the role of soluble mediators in activating immune suppression

Mechanisms Underlying Stress Fracture and the Influence of Sex and Race/Ethnicity

Science.gov (United States)

2017-10-01

AWARD NUMBER: W81XWH-16-1-0652 TITLE: Mechanisms Underlying Stress Fracture and the Influence of Sex and Race/Ethnicity PRINCIPAL INVESTIGATOR...5a. CONTRACT NUMBER W81XWH-16-1-0652 Mechanisms Underlying Stress Fracture and the Influence of Sex and Race/Ethnicity 5b. GRANT NUMBER W81XWH...to stress fracture risk. In particular, in Study 1, we will perform advanced skeletal imaging along with gait-assessments in subjects with history of

Adsorption mechanism of magnetically separable Fe_3O_4/graphene oxide hybrids

International Nuclear Information System (INIS)

Ouyang, Ke; Zhu, Chuanhe; Zhao, Ya; Wang, Leichao; Xie, Shan; Wang, Qun

2015-01-01

Graphical abstract: A recyclable Fe_3O_4/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polylol approach and exhibited an effective adsorption of BPA in aqueous solution. - Highlights: • Magnetically separable Fe_3O_4/GO hybrids were synthesized via a facile one-pot polylol approach. • The Fe_3O_4/GO hybrid could be easily recovered and met the need of magnetic separation, exhibiting excellent reproducibility and reusability. • The hybrids showed excellent adsorption ability for bisphenol A in aqueous solution. • The effect of pH value, temperature and coexisting ions on the adsorption was studied. • π–π interactions were postulated to be the primary mechanisms of adsorption of BPA on Fe_3O_4/GO hybrids. - Abstract: A reclaimable Fe_3O_4/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polyol approach and employed as a recyclable adsorbent for Bisphenol A (BPA) in aqueous solutions. The maximum adsorption capacity (q_m) of the Fe_3O_4/GO hybrid for BPA was 72.80 mg/g at 273 K. The kinetics of the adsorption process and the adsorption isotherm data were fitted using the Freundlich equation and a pseudo-second-order kinetic model. The results of the thermodynamic parameters ΔH°, ΔS° and ΔG° showed that the adsorption process was exothermic and spontaneous. Furthermore, the reusability of the samples was investigated, and the results indicated that the samples exhibited high stability. The magnetic characterization demonstrated that hybrids were superparamagnetic and could be recovered conveniently by magnetic separation. The strong π–π interaction was determined to be the predominant driving force behind the adsorption of BPA onto the Fe_3O_4/GO hybrid. Therefore, the Fe_3O_4/GO hybrid could be regarded as a potential adsorbent for wastewater treatment and purification processes.

Evaluation of starter dietary digestible lysine level on broilers raised under a sex-separated or straight-run housing regime, part 2: Economics of sex separation and digestible lysine level for maximum returns.

Science.gov (United States)

Da Costa, M J; Colson, G; Frost, T J; Halley, J; Pesti, G M

2017-09-01

The objective of this experiment was to determine the maximum net returns digestible lysine (dLys) levels (MNRL) when maintaining the ideal amino acid ratio for starter diets of broilers raised sex separate or comingled (straight-run). A total of 3,240 Ross 708 chicks was separated by sex and placed in 90 pens by 2 rearing types: sex separate (36 males or 36 females) or straight-run (18 males + 18 females). Each rearing type was fed 6 starter diets (25 d) formulated to have dLys levels between 1.05 and 1.80%. A common grower diet with 1.02% of dLys was fed from 25 to 32 days. Body weight gain (BWG) and feed intake were assessed at 25 and 32 d for performance evaluation. Additionally, at 26 and 33 d, 4 birds per pen were sampled for carcass yield evaluation. Data were modeled using response surface methodology in order to estimate feed intake and whole carcass weight at 1,600 g live BW. Returns over feed cost were estimated for a 1.8-million-broiler complex of each rearing system under 9 feed/meat price scenarios. Results indicated that females needed more feed to reach market weight, followed by straight-run birds, and then males. At medium meat and feed prices, female birds had MNRL at 1.07% dLys, whereas straight-run and males had MNRL at 1.05%. As feed and meat prices increased, females had MNRL increased up to 1.15% dLys. Sex separation resulted in increased revenue under certain feed and meat prices, and before sex separation cost was deducted. When the sexing cost was subtracted from the returns, sex separation was not shown to be economically viable when targeting birds for light market BW. © 2017 Poultry Science Association Inc.

Failure Mechanisms of Brittle Rocks under Uniaxial Compression

Science.gov (United States)

Liu, Taoying; Cao, Ping

2017-09-01

The behaviour of a rock mass is determined not only by the properties of the rock matrix, but mostly by the presence and properties of discontinuities or fractures within the mass. The compression test on rock-like specimens with two prefabricated transfixion fissures, made by pulling out the embedded metal inserts in the pre-cured period was carried out on the servo control uniaxial loading tester. The influence of the geometry of pre-existing cracks on the cracking processes was analysed with reference to the experimental observation of crack initiation and propagation from pre-existing flaws. Based on the rock fracture mechanics and the stress-strain curves, the evolution failure mechanism of the fissure body was also analyzed on the basis of exploring the law of the compression-shear crack initiation, wing crack growth and rock bridge connection. Meanwhile, damage fracture mechanical models of a compression-shear rock mass are established when the rock bridge axial transfixion failure, tension-shear combined failure, or wing crack shear connection failure occurs on the specimen under axial compression. This research was of significance in studying the failure mechanism of fractured rock mass.

Physical Separation in the Workplace

DEFF Research Database (Denmark)

Stea, Diego; Foss, Nicolai Juul; Holdt Christensen, Peter

2015-01-01

Physical separation is pervasive in organizations, and has powerful effects on employee motivation and organizational behaviors. However, research shows that workplace separation is characterized by a variety of tradeoffs, tensions, and challenges that lead to both positive and negative outcomes....... We develop new theory on the nature, antecedents, and motivational implications of separation awareness - a psychological state in which people are aware of their physical separation from others—and proffer a model of the mechanisms that link separation and motivation. We distinguish between control...... and autonomy affirmation as psychological states that are triggered by physical separation in the workplace, and discuss individual and context specific moderators, as well as motivational implications of separation awareness. In doing so, we reconcile the seemingly contradicting findings that have been...

Effect of acid- and alkaline-aided extractions on functional and rheological properties of proteins recovered from mechanically separated turkey meat (MSTM).

Science.gov (United States)

Hrynets, Yuliya; Omana, Dileep A; Xu, Yan; Betti, Mirko

2010-09-01

Functional and rheological characteristics of acid- and alkali-extracted proteins from mechanically separated turkey meat (MSTM) have been investigated. Extractions were carried out at 4 pH values (2.5, 3.5, 10.5, and 11.5). The study demonstrated that alkali and acid extractions resulted in significant (P hardness, chewiness, springiness, and cohesiveness) of recovered proteins were found to be unaffected (P > 0.05) by different extraction pH. The protein extracted at pH 3.5 formed a highly viscoelastic gel network as evidenced by storage modulus (G') values, whereas the gel formed from proteins extracted at pH 10.5 was found to be the weakest. The work also revealed that acid treatments were more effective for removal of total heme pigments from MSTM. Color characteristics of protein isolates were markedly improved compared to the initial material and tended to be better when subjected to acid extractions. Mechanically separated meat is one of the cheapest sources of protein obtained by grinding meat and bones together and forcing the mixture through a perforated drum. The use of mechanically separated turkey meat (MSTM) for the production of further processed poultry products is limited due to its undesirable color and textural properties. Recovery of proteins from MSTM using pH shifting process will help the poultry processors to get better returns and also create opportunity to produce functional food ingredients.

The non-separability of ''dielectric'' and ''mechanical'' friction in molecular systems: A simulation study

International Nuclear Information System (INIS)

Kumar, P. V.; Maroncelli, M.

2000-01-01

Simulations of the time-dependent friction controlling rotational, translational, and vibrational motions of dipolar diatomic solutes in acetonitrile and methanol have been used to examine the nature of ''dielectric'' friction. The way in which electrical interactions increase the friction beyond that present in nonpolar systems is found to be rather different than what is anticipated by most theories of dielectric friction. Long-range electrostatic forces do not simply add an independent contribution to the friction due to short-ranged or ''mechanical'' sources (modeled here in terms of Lennard-Jones forces). Rather, the electrical and Lennard-Jones contributions are found to be strongly anticorrelated and not separable in any useful way. For some purposes, the mechanism by which electrical interactions increase friction is better viewed as a static electrostriction effect: electrical forces cause a subtle increase in atomic density in the solute's first solvation shell, which increases the amplitude of the force fluctuations derived from the Lennard-Jones interactions, i.e., the mechanical friction. However, electrical interactions also modify the dynamics of the friction, typically adding a long-time tail, which significantly increases the integral friction. Both of these effects must be included in a correct description of friction in the presence of polar interactions. (c) 2000 American Institute of Physics

Superconducting open-gradient magnetic separation for the pretreatment of radioactive or mixed waste vitrification feeds. 1998 annual progress report

International Nuclear Information System (INIS)

Crawford, C.; Doctor, R.D.; Landsberger, S.; Nunez, L.; Ritter, J.

1998-01-01

'The objective is to reduce the volume and cost of high-level waste glass produced during US DOE remediation activities by demonstrating that magnetic separation can separate crystalline, amorphous, and colloidal constituents in vitrification feed streams known to be deleterious to the production of borosilicate glass. Magnetic separation will add neither chemicals nor generate secondary waste streams. The project includes the systematic study of magnetic interactions of waste constituents under controlled physical and chemical conditions (e.g., hydration, oxidation, temperature) to identify mechanisms that control the magnetic properties. Partitioning of radionuclides to determine their sorption mechanisms is also being studied. The identification of fundamental magnetic properties within the microscopic chemical environment in combination with hydrodynamic and electrodynamic models provides insights into the design of a system for optimal separation. Following this, experimental studies using superconducting open-gradient magnetic separation (OGMS) will be conducted to validate its effectiveness as a pretreatment technique.'

Dynamic Computational Model of Symptomatic Bacteremia to Inform Bacterial Separation Treatment Requirements.

Directory of Open Access Journals (Sweden)

Sinead E Miller

Full Text Available The rise of multi-drug resistance has decreased the effectiveness of antibiotics, which has led to increased mortality rates associated with symptomatic bacteremia, or bacterial sepsis. To combat decreasing antibiotic effectiveness, extracorporeal bacterial separation approaches have been proposed to capture and separate bacteria from blood. However, bacteremia is dynamic and involves host-pathogen interactions across various anatomical sites. We developed a mathematical model that quantitatively describes the kinetics of pathogenesis and progression of symptomatic bacteremia under various conditions, including bacterial separation therapy, to better understand disease mechanisms and quantitatively assess the biological impact of bacterial separation therapy. Model validity was tested against experimental data from published studies. This is the first multi-compartment model of symptomatic bacteremia in mammals that includes extracorporeal bacterial separation and antibiotic treatment, separately and in combination. The addition of an extracorporeal bacterial separation circuit reduced the predicted time of total bacteria clearance from the blood of an immunocompromised rodent by 49%, compared to antibiotic treatment alone. Implementation of bacterial separation therapy resulted in predicted multi-drug resistant bacterial clearance from the blood of a human in 97% less time than antibiotic treatment alone. The model also proposes a quantitative correlation between time-dependent bacterial load among tissues and bacteremia severity, analogous to the well-known 'area under the curve' for characterization of drug efficacy. The engineering-based mathematical model developed may be useful for informing the design of extracorporeal bacterial separation devices. This work enables the quantitative identification of the characteristics required of an extracorporeal bacteria separation device to provide biological benefit. These devices will potentially

Method for separating isotopes

International Nuclear Information System (INIS)

Schlenker, R.F.

1978-01-01

A vortex tube for separating isotopes is described. A gas mixture containing the isotopic molecules enters the vortex tube under pressure and is separated into a hot discharge flow stream and a cold discharge flow stream. The hot discharge is enriched in lighter isotopic molecules whereas the cold discharge flow stream is enriched in the heavier isotopic molecules. The vortex tube can be used in a single stage or multistage isotope separation apparatus

Experimental Study of Unsteady Flow Separation in a Laminar Boundary Layer

Science.gov (United States)

Bonacci, Andrew; Lang, Amy; Wahidi, Redha; Santos, Leonardo

2017-11-01

Flow separation, caused by an adverse pressure gradient, is a major problem in many applications. Reversing flow near the wall is the first sign of incipient separation and can bristle shark scales which may be linked to a passive, flow actuated separation control mechanism. An investigation of how this backflow forms and how it interacts with shark skin is of interest due to the fact that this could be used as a bioinspired means of initiating flow control. A water tunnel experiment aims to study unsteady separation with a focus on the reversing flow development near the wall within a flat plate laminar boundary layer (Re on order of 105) as an increasing adverse pressure gradient is induced by a rotating cylinder. Unsteady reversing flow development is documented using DPIV. Funding was provided by the National Science Foundation under the Research Experience for Undergraduates (REU) program (EEC 1659710) and the Army Research Office.

Particle separator at Los Alamos

International Nuclear Information System (INIS)

Liska, D.J.

1975-01-01

The beam separator under development at LAMPF for the EPICS channel (Energetic Pion Channel and Spectrometer) is described. The separator operates on the electrostatic crossed-field principle but has several unusual features. (U.S.)

Separation of atropisomers by chiral liquid chromatography and thermodynamic analysis of separation mechanism

OpenAIRE

Ling Zhang; Yue Hu; Elizabeth Galella; Frank P. Tomasella; William P. Fish

2017-01-01

In the pharmaceutical industry, the analysis of atropisomers is of considerable interest from a scientific and regulatory perspective. The compound of interest contains two stereogenic axes due to the hindered rotation around the single bonds connecting the aryl groups, which results in four potential configurational isomers (atropisomers). The separation of the four atropisomers is achieved on a derivatized β-cyclodextrin bonded stationary phase. Further investigation shows that low temperat...

Are carnivore digestive separation mechanisms revealed on structure-rich diets?: Faecal inconsistency in dogs (Canis familiaris) fed day old chicks

NARCIS (Netherlands)

Cuyper, De Annelies; Clauss, M.; Hesta, Myriam; Cools, An; Bosch, G.; Hendriks, W.H.; Janssens, Geert P.J.

2018-01-01

Pronounced variations in faecal consistency have been described anecdotally for some carnivore species fed a structure-rich diet. Typically two faecal consistencies are distinguished, namely hard and firm versus liquid and viscous faeces. It is possible that a separation mechanism is operating in

EFFICIENCY OF METAL SCRAP SEPARATION IN EDDY CURRENT SEPARATOR

Directory of Open Access Journals (Sweden)

Gordan Bedeković

2008-11-01

Full Text Available Eddy-current separation is most often method used for the recovery of non-ferrous metals (Al, Cu, Zn, Pb from solid wastes and also for separating non-ferrous metals from each other. The feed material comes to rotary drum and magnetic field by belt conveyer. The changing magnetic field induce eddy currents in conductive (metallic particles. Because interaction between this currents and the magnetic field electrodynamic forces will act on conductive particles. Therefore the trajectories of conductive particles will be different from the trajectories of the non-conductive ones. Separation is a result of the combined actions of several forces (electrodynamic, gravitational and frictional. The paper presents results of aluminium recovery from mixture of metallic particles in eddy current separator. Testing were conducted under field condition. Results shows that is possible achieve recovery of 99 % and concentrate quality of 89 % of aluminium (the paper is published in Croatian.

Phase separation driven by density-dependent movement: A novel mechanism for ecological patterns.

Science.gov (United States)

Liu, Quan-Xing; Rietkerk, Max; Herman, Peter M J; Piersma, Theunis; Fryxell, John M; van de Koppel, Johan

2016-12-01

Many ecosystems develop strikingly regular spatial patterns because of small-scale interactions between organisms, a process generally referred to as spatial self-organization. Self-organized spatial patterns are important determinants of the functioning of ecosystems, promoting the growth and survival of the involved organisms, and affecting the capacity of the organisms to cope with changing environmental conditions. The predominant explanation for self-organized pattern formation is spatial heterogeneity in establishment, growth and mortality, resulting from the self-organization processes. A number of recent studies, however, have revealed that movement of organisms can be an important driving process creating extensive spatial patterning in many ecosystems. Here, we review studies that detail movement-based pattern formation in contrasting ecological settings. Our review highlights that a common principle, where movement of organisms is density-dependent, explains observed spatial regular patterns in all of these studies. This principle, well known to physics as the Cahn-Hilliard principle of phase separation, has so-far remained unrecognized as a general mechanism for self-organized complexity in ecology. Using the examples presented in this paper, we explain how this movement principle can be discerned in ecological settings, and clarify how to test this mechanism experimentally. Our study highlights that animal movement, both in isolation and in unison with other processes, is an important mechanism for regular pattern formation in ecosystems. Copyright © 2016 Elsevier B.V. All rights reserved.

Electro/powder separation process

International Nuclear Information System (INIS)

Dunn, J.P.

1977-01-01

A report is presented to introduce the ELECTRO/POWDER process to the P/M Industry. The process effectively uses electrostatic forces to convey, sort, meter, and blend fine powders. The major advantages of this separating process consist of the processing of primary particles, low particle energy due to particle velocity control and the pattern of particle movement over the sieve (vertical oscillation of particles above the sieve aperture). The report briefly describes the forces involved in both mechanical and sieving devices, with major emphasis on the operating principles of this process. Sieve separation of particulates is basically the result of two physical separating processes which occur simultaneously or independently; separation (dispersion) of particulates from each other and the size separation by passage through fixed apertures. In order to accomplish this goal, mechanical sieving devices utilize various motions to induce shear forces between the sieve surface and the particulates, and between the particulates themselves. It is noted that the ELECTRO/POWDER process is making steady progress in becoming an industrial tool for sieving and feeding of fine particles. Its potential extends into both the blending and admixing of powders, either by incorporating two opposing feeders, one being charged with the opposite polarity or by modifying the ELECTRO/SIEVE to incorporate more than one input and a solid electrode to replace the sieve electrode

Separations by centrifugal phenomena

International Nuclear Information System (INIS)

Hsu, H.W.

1981-01-01

The technical information presented herein emphasizes the uniqueness of the centrifugal separations methodology and pertinent theory for various kinds of centrifugation. The topics are arranged according to gas, liquid, and solid phases, in the order of increasing densities. Much space is devoted to liquid centrifugation because of the importance of this technique in chemical and biological laboratories. Many separational and characterizational examples are illustrated in detail. The material has been divided into 7 chapters entitled: 1) Introduction, 2) Basic Theory of Centrifugation, 3) Gas Centrifuges, 4) Preparative Liquid Centrifuges, 5) Analytical Liquid Centrifuges, 6) Liquid Centrifuges in Practice, and 7) Mechanical Separations by Centrifuges. Separate abstracts have been prepared for each chapter except the introduction

Mechanisms Underlying the Antidepressant Response and Treatment Resistance

Directory of Open Access Journals (Sweden)

Marjorie Rose Levinstein

2014-06-01

Full Text Available Depression is a complex and heterogeneous disorder affecting millions of Americans. There are several different medications and other treatments that are available and effective for many patients with depression. However, a substantial percentage of patients fail to achieve remission with these currently available interventions, and relapse rates are high. Therefore, it is necessary to determine both the mechanisms underlying the antidepressant response and the differences between responders and non-responders to treatment. Delineation of these mechanisms largely relies on experiments that utilize animal models. Therefore, this review provides an overview of the various mouse models that are currently used to assess the antidepressant response, such as chronic mild stress, social defeat, and chronic corticosterone. We discuss how these mouse models can be used to advance our understanding of the differences between responders and non-responders to antidepressant treatment. We also provide an overview of experimental treatment modalities that are used for treatment-resistant depression, such as deep brain stimulation and ketamine administration. We will then review the various genetic polymorphisms and transgenic mice that display resistance to antidepressant treatment. Finally, we synthesize the published data to describe a potential neural circuit underlying the antidepressant response and treatment resistance.

Depression and Chronic Liver Diseases: Are There Shared Underlying Mechanisms?

Directory of Open Access Journals (Sweden)

Xiaoqin Huang

2017-05-01

Full Text Available The occurrence of depression is higher in patients with chronic liver disease (CLD than that in the general population. The mechanism described in previous studies mainly focused on inflammation and stress, which not only exists in CLD, but also emerges in common chronic diseases, leaving the specific mechanism unknown. This review was to summarize the prevalence and risk factors of depression in CLD including chronic hepatitis B, chronic hepatitis, alcoholic liver disease, and non-alcoholic fatty liver disease, and to point out the possible underlying mechanism of this potential link. Clarifying the origins of this common comorbidity (depression and CLD may provide more information to understand both diseases.

Photoinduced charge separation at polymer-fullerene interfaces of BHJ solar cells (Conference Presentation)

Science.gov (United States)

Poluektov, Oleg G.; Niklas, Jens; Mardis, Kristy

2016-09-01

While photovoltaic cells are highly promising man-made devices for direct solar energy utilization, a number of fundamental questions about how the organic bulk heterojunction cell enables efficient long-lived and long-range charge separation remain unanswered. These questions were address by employing an advanced suite of EPR spectroscopy in combination with DFT calculations to study mechanism of charge separation at the polymer-fullerene interfaces of photo-active BHJ. Observed charge delocalization in BHJ upon photoinduced ET is analogous to that in organic donor-acceptor material. This is an efficient mechanism of charge stabilization in photosynthetic assemblies. Time-resolved EPR spectra show a strong polarization pattern for all polymer-fullerene blends under study, which is caused by non-Boltzmann population of the electron spin energy levels in the radical pairs. The first observation of this phenomenon was reported in natural and artificial photosynthetic assemblies, and comparison with these systems allows us to better understand charge separation processes in OPVs. The spectral analysis presented here, in combination with DFT calculations, shows that CS processes in OPV materials are similar to that in organic photosynthetic systems. This work was supported by the U.S. Department of Energy, Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, and Biosciences, under Contract DE-AC02-06CH11357 at Argonne National Laboratory.

Mechanical Behavior of Shale Rock under Uniaxial Cyclic Loading and Unloading Condition

Directory of Open Access Journals (Sweden)

Baoyun Zhao

2018-01-01

Full Text Available In order to investigate the mechanical behavior of shale rock under cyclic loading and unloading condition, two kinds of incremental cyclic loading tests were conducted. Based on the result of the short-term uniaxial incremental cyclic loading test, the permanent residual strain, modulus, and damage evolution were analyzed firstly. Results showed that the relationship between the residual strains and the cycle number can be expressed by an exponential function. The deformation modulus E50 and elastic modulus ES first increased and then decreased with the peak stress under the loading condition, and both of them increased approximately linearly with the peak stress under the unloading condition. On the basis of the energy dissipation, the damage variables showed an exponential increasing with the strain at peak stress. The creep behavior of the shale rock was also analyzed. Results showed that there are obvious instantaneous strain, decay creep, and steady creep under each stress level and the specimen appears the accelerated creep stage under the 4th stress of 51.16 MPa. Based on the characteristics of the Burgers creep model, a viscoelastic-plastic creep model was proposed through viscoplastic mechanics, which agrees very well with the experimental results and can better describe the creep behavior of shale rock better than the Burgers creep model. Results can provide some mechanics reference evidence for shale gas development.

Agarose gel electrophoresis for the separation of DNA fragments.

Science.gov (United States)

Lee, Pei Yun; Costumbrado, John; Hsu, Chih-Yuan; Kim, Yong Hoon

2012-04-20

Agarose gel electrophoresis is the most effective way of separating DNA fragments of varying sizes ranging from 100 bp to 25 kb(1). Agarose is isolated from the seaweed genera Gelidium and Gracilaria, and consists of repeated agarobiose (L- and D-galactose) subunits(2). During gelation, agarose polymers associate non-covalently and form a network of bundles whose pore sizes determine a gel's molecular sieving properties. The use of agarose gel electrophoresis revolutionized the separation of DNA. Prior to the adoption of agarose gels, DNA was primarily separated using sucrose density gradient centrifugation, which only provided an approximation of size. To separate DNA using agarose gel electrophoresis, the DNA is loaded into pre-cast wells in the gel and a current applied. The phosphate backbone of the DNA (and RNA) molecule is negatively charged, therefore when placed in an electric field, DNA fragments will migrate to the positively charged anode. Because DNA has a uniform mass/charge ratio, DNA molecules are separated by size within an agarose gel in a pattern such that the distance traveled is inversely proportional to the log of its molecular weight(3). The leading model for DNA movement through an agarose gel is "biased reptation", whereby the leading edge moves forward and pulls the rest of the molecule along(4). The rate of migration of a DNA molecule through a gel is determined by the following: 1) size of DNA molecule; 2) agarose concentration; 3) DNA conformation(5); 4) voltage applied, 5) presence of ethidium bromide, 6) type of agarose and 7) electrophoresis buffer. After separation, the DNA molecules can be visualized under uv light after staining with an appropriate dye. By following this protocol, students should be able to: Understand the mechanism by which DNA fragments are separated within a gel matrix Understand how conformation of the DNA molecule will determine its mobility through a gel matrix Identify an agarose solution of appropriate

Vascular mechanisms underlying the hypotensive effect of Rumex acetosa.

Science.gov (United States)

Qamar, Hafiz Misbah-Ud-Din; Qayyum, Rahila; Salma, Umme; Khan, Shamim; Khan, Taous; Shah, Abdul Jabbar

2018-12-01

Rumex acetosa L. (Polygonaceae) is well known in traditional medicine for its therapeutic efficacy as an antihypertensive. The study investigates antihypertensive potential of crude methanol extract (Ra.Cr) and fractions of Rumex acetosa in normotensive and hypertensive rat models and probes the underlying vascular mechanisms. Ra.Cr and its fractions were tested in vivo on normotensive and hypertensive Sprague-Dawley rats under anaesthesia for blood pressure lowering effect. In vitro experiments on rat and Oryctolagus cuniculus rabbit aortae were employed to probe the underlying vasorelaxant mechanism. In normotensive rats under anaesthesia, Ra.Cr caused fall in MAP (40 mmHg) at 50 mg/kg with % fall of 27.88 ± 4.55. Among the fractions tested, aqueous fraction was more potent at the dose of 50 mg/kg with % fall of 45.63 ± 2.84. In hypertensive rats under similar conditions, extract and fractions showed antihypertensive effect at same doses while aqueous fraction being more potent, exhibited 68.53 ± 4.45% fall in MAP (70 mmHg). In isolated rat aortic rings precontracted with phenylephrine (PE), Ra.Cr and fractions induced endothelium-dependent vasorelaxation, which was partially blocked in presence of l-NAME, indomethacin and atropine. In isolated rabbit aortic rings pre-contracted with PE and K + -(80 mM), Ra.Cr induced vasorelaxation and shifted Ca 2+ concentration-response curves to the right and suppressed PE peak formation, similar to verapamil, in Ca 2+ -free medium. The data indicate that l-NAME and atropine-sensitive endothelial-derived NO and COX enzyme inhibitors and Ca 2+ entry blocking-mediated vasodilator effect of the extract explain its antihypertensive potential.

10 CFR Appendix N to Part 110 - Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment Under NRC's...

Science.gov (United States)

2010-01-01

..., Plants and Equipment Under NRC's Export Licensing Authority N Appendix N to Part 110 Energy NUCLEAR REGULATORY COMMISSION (CONTINUED) EXPORT AND IMPORT OF NUCLEAR EQUIPMENT AND MATERIAL Pt. 110, App. N Appendix N to Part 110—Illustrative List of Lithium Isotope Separation Facilities, Plants and Equipment...

Development of a dry-mechanical procedure for separating a mixture of two non-uniform grain fractions of HTR feed and breed particles

International Nuclear Information System (INIS)

Hartmann, K.

1979-05-01

If the feed-breed-particle system is employed the Head-End of the reprocessing of HTR-fuel elements requires another separation step, the so called feed-breed separation. In this report a dry-mechanical procedure is described for separating a mixture consisting of unirradiated TRISO-feed and BISO-breed particles, matrix carbon, and broken kernels and hulls by a combination of a zigzag pneumatic classifier with a magnetic separator. The feed and breed crossover rates are less than 1 percent. Furthermore, measurements of the susceptibilities of the following materials have been carried out with the magnetic separator: unirradiated feed and breed particles and unbroken kernels, feed and breed kernels with a simulated burn-up, irradiated UO 2 -kernels (80% fifa). The results show that UO 2 -kernels keep their paramagnetic character if irradiated and that the difference between the susceptibilities of feed and breed kernels is sufficient for a complete magnetic separation. In addition, a procedure is proposed for separating a mixture of TRISO-feed and TRISO-breed particles and the average particle diameter is assessed which can be expected to give the best separation by the zigzag pneumatic classifier. (orig.) [de

Magnetically separable CuFe{sub 2}O{sub 4}/AgBr composite photocatalysts: Preparation, characterization, photocatalytic activity and photocatalytic mechanism under visible light

Energy Technology Data Exchange (ETDEWEB)

Zhao, Yalei; Lin, Cuiping; Bi, Huijie; Liu, Yonggang; Yan, Qishe, E-mail: Qisheyanzzu@163.com

2017-01-15

Highlights: • CuFe{sub 2}O{sub 4}/AgBr composites were prepared by a facile sol-gel and hydrothermal method. • Visible-light response and high photocatalytic performance. • Excellent magnetic properties. • Different reactive species had different effects on degradation different pollutants. - Abstract: The CuFe{sub 2}O{sub 4} and CuFe{sub 2}O{sub 4}/AgBr composites with different CuFe{sub 2}O{sub 4} contents were prepared by a facile sol-gel and hydrothermal method, respectively. The as-synthesized photocatalysts were characterized by means of powder X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectrum (UV–vis DRS). Their magnetic properties, photocatalytic degradation activities on methyl orange (MO) and tetracycline hydrochloride (TC) solution and photocatalytic mechanism were investigated in detail. The results revealed that the CuFe{sub 2}O{sub 4}/AgBr composites exhibited significantly higher photocatalytic activities than the pure CuFe{sub 2}O{sub 4}. The enhanced photocatalytic activity could be attributed to the matched band structure of two components and more effective charge transportation and separations. In addition, the quenching investigation of different scavengers demonstrated that h{sup +}, ·OH, ·O{sub 2}{sup −} reactive species played different roles in the decolorization of MO and degradation of TC.

Environmental impacts of combining pig slurry acidification and separation under different regulatory regimes - a life cycle assessment

DEFF Research Database (Denmark)

ten Hoeve, Marieke; Gomez Muñoz, Beatriz; Jensen, Lars Stoumann

2016-01-01

Global livestock production is increasing rapidly, leading to larger amounts of manure and environmental impacts. Technologies that can be applied to treat manure in order to decrease certain environmental impacts include separation and acidification. In this study, a life cycle assessment was used...... on the environmental impacts of the technologies. The impact categories analysed were climate change, terrestrial, marine and freshwater eutrophication, fossil resource depletion and toxicity potential. In-house slurry acidification appeared to be the most beneficial scenario under both N and P regulations. Slurry...... separation led to a lower freshwater eutrophication potential than the other scenarios in which N regulations alone were in force, while these environmental benefits disappeared after implementation of stricter P regulations. With N regulations alone, there was a synergetic positive effect of combining in-house...

Electrophoretic separation of cells and particles from rat pituitary and rat spleen

Science.gov (United States)

Hymer, Wesley C.

1993-01-01

There are 3 parts to the IML-2 TX-101 experiment. Part 1 is a pituitary cell culture experiment. Part 2 is a pituitary cell separation experiment using the Japanese free flow electrophoresis unit (FFEU). Part 3 is a pituitary secretory granule separation experiment using the FFEU. The objectives of this three part experiment are: (1) to determine the kinetics of production of biologically active growth hormone (GH) and prolactin (PRL) in rat pituitary GH and PRL cells in microgravity (micro-g); (2) to investigate three mechanisms by which a micro-g-induced lesion in hormone production may occur; and (3) to determine the quality of separations of pituitary cells and organelles by continuous flow electrophoresis (CFE) in micro-g under conditions where buoyancy-induced convection is eliminated.

A possible realization of Einstein's causal theory underlying quantum mechanics

International Nuclear Information System (INIS)

Yussouff, M.

1979-06-01

It is shown that a new microscopic mechanics formulated earlier can be looked upon as a possible causal theory underlying quantum mechanics, which removes Einstein's famous objections against quantum theory. This approach is free from objections raised against Bohm's hidden variable theory and leads to a clear physical picture in terms of familiar concepts, if self interactions are held responsible for deviations from classical behaviour. The new level of physics unfolded by this approach may reveal novel frontiers in high-energy physics. (author)

Magnetic separation from superparamagnetic particle suspensions

International Nuclear Information System (INIS)

Sinha, Ashok; Ganguly, Ranjan; Puri, Ishwar K.

2009-01-01

We investigate the magnetophoretic separation of magnetic microparticles from a non-dilute flow in a microfluidic channel and their subsequent field-induced aggregation under the influence of an externally applied magnetic force. This force induces dipolar interactions between the particles that aid in their separation from the flow. Existing analytical models for dilute suspensions cannot be extended to non-dilute suspensions in which interparticle magnetic interactions play an important role. We therefore conduct a parametric investigation of the mechanics of this problem in a microcapillary flow through simulations and experimental visualization. When a magnetic field is applied, the magnetic microparticles form an aggregate on the channel wall that is influenced by the competition between the holding magnetic force and the aggregate-depleting flow shear force. Microparticle collection in the aggregate increases linearly with increasing magnetic field strength and is characterized by distinct buildup and washaway phases. The collected microparticle volume fraction in an aggregate is found to depend on a single dimensional group that depends upon characteristic system parameters.

Cognitive mechanisms underlying disorganization of thought in a genetic syndrome (47,XXY)

NARCIS (Netherlands)

Van Rijn, Sophie; Aleman, Andre; De Sonneville, Leo; Swaab, Hanna

Because of the risk for development of psychopathology such as psychotic symptoms, it has been suggested that studying men with the XXY karyotype may help in the search for underlying cognitive, neural and genetic mechanisms. The aim of this study was to identify cognitive mechanisms that may

First-principles investigation of mechanical and electronic properties of tetragonal NbAl3 under tension

Science.gov (United States)

Jiao, Zhen; Liu, Qi-Jun; Liu, Fu-Sheng; Tang, Bin

2018-06-01

Using the density functional theory calculations, the mechanical and electronic properties of NbAl3 under different tensile loads were investigated. The calculated lattice parameters, elastic constants and mechanical properties (bulk modulus, shear modulus, Young's modulus, Poisson's ratio, Pugh's criterion and Cauchy's pressure) indicated that our results were in agreement with the published experimental and theoretical data at zero tension. With respect to NbAl3 under tension in this paper, the crystal structure was changed from tetragonal to orthorhombic under tension along the [100] and [101] directions. The NbAl3 crystal has been classified as brittle material under tension from 0 to 20 GPa. The obtained Young's modulus and Debye temperature monotonically decreased with increasing tension stress. Combining with mechanical and electronic properties in detail, the decreased mechanical properties were mainly due to the weakening of covalency.

Kinetic theory approach to modeling of cellular repair mechanisms under genome stress.

Directory of Open Access Journals (Sweden)

Jinpeng Qi

Full Text Available Under acute perturbations from outer environment, a normal cell can trigger cellular self-defense mechanism in response to genome stress. To investigate the kinetics of cellular self-repair process at single cell level further, a model of DNA damage generating and repair is proposed under acute Ion Radiation (IR by using mathematical framework of kinetic theory of active particles (KTAP. Firstly, we focus on illustrating the profile of Cellular Repair System (CRS instituted by two sub-populations, each of which is made up of the active particles with different discrete states. Then, we implement the mathematical framework of cellular self-repair mechanism, and illustrate the dynamic processes of Double Strand Breaks (DSBs and Repair Protein (RP generating, DSB-protein complexes (DSBCs synthesizing, and toxins accumulating. Finally, we roughly analyze the capability of cellular self-repair mechanism, cellular activity of transferring DNA damage, and genome stability, especially the different fates of a certain cell before and after the time thresholds of IR perturbations that a cell can tolerate maximally under different IR perturbation circumstances.

Kinetic theory approach to modeling of cellular repair mechanisms under genome stress.

Science.gov (United States)

Qi, Jinpeng; Ding, Yongsheng; Zhu, Ying; Wu, Yizhi

2011-01-01

Under acute perturbations from outer environment, a normal cell can trigger cellular self-defense mechanism in response to genome stress. To investigate the kinetics of cellular self-repair process at single cell level further, a model of DNA damage generating and repair is proposed under acute Ion Radiation (IR) by using mathematical framework of kinetic theory of active particles (KTAP). Firstly, we focus on illustrating the profile of Cellular Repair System (CRS) instituted by two sub-populations, each of which is made up of the active particles with different discrete states. Then, we implement the mathematical framework of cellular self-repair mechanism, and illustrate the dynamic processes of Double Strand Breaks (DSBs) and Repair Protein (RP) generating, DSB-protein complexes (DSBCs) synthesizing, and toxins accumulating. Finally, we roughly analyze the capability of cellular self-repair mechanism, cellular activity of transferring DNA damage, and genome stability, especially the different fates of a certain cell before and after the time thresholds of IR perturbations that a cell can tolerate maximally under different IR perturbation circumstances.

Control of a perturbed under-actuated mechanical system

KAUST Repository

Zayane, Chadia

2015-11-05

In this work, the trajectory tracking problem for an under-actuated mechanical system in presence of unknown input disturbances is addressed. The studied inertia wheel inverted pendulum falls in the class of non minimum phase systems. The proposed high order sliding mode control architecture including a controller and differentiator allows to track accurately the predefined trajectory and to stabilize the internal dynamics. The robustness of the proposed approach is illustrated through different perturbation and output noise configurations.

Mechanisms underlying astringency: introduction to an oral tribology approach

Science.gov (United States)

Upadhyay, Rutuja; Brossard, Natalia; Chen, Jianshe

2016-03-01

Astringency is one of the predominant factors in the sensory experience of many foods and beverages ranging from wine to nuts. The scientific community is discussing mechanisms that explain this complex phenomenon, since there are no conclusive results which correlate well with sensory astringency. Therefore, the mechanisms and perceptual characteristics of astringency warrant further discussion and investigation. This paper gives a brief introduction of the fundamentals of oral tribology forming a basis of the astringency mechanism. It discusses the current state of the literature on mechanisms underlying astringency describing the existing astringency models. The review discusses the crucial role of saliva and its physiology which contributes significantly in astringency perception in the mouth. It also provides an overview of research concerned with the physiological and psychophysical factors that mediate the perception of this sensation, establishing the ground for future research. Thus, the overall aim of the review is to establish the critical roles of oral friction (thin-film lubrication) in the sensation of astringency and possibly of some other specific sensory features.

Electrospun Nanofibers for Sandwiched Polyimide/Poly (vinylidene fluoride)/Polyimide Separators with the Thermal Shutdown Function

International Nuclear Information System (INIS)

Wu, Dezhi; Shi, Chuan; Huang, Shaohua; Qiu, Xiaochun; Wang, Huan; Zhan, Zhan; Zhang, Peng; Zhao, Jinbao; Sun, Daoheng; Lin, Liwei

2015-01-01

Nanofibers fabricated by the electrospinning process have been used to construct sandwich-type Polyimide/Poly (vinylidene fluoride)/Polyimide (PI/PVDF/PI) separators with the thermal shutdown function for lithium ion batteries. This architecture uses the good thermal stability of PI as the top and bottom structure layers. Under high temperature operations, the middle layer made of PVDF nanofibers can melt and form a pore-free film to shut down the battery operation. The electrolyte uptake and ionic conductivity of the PI/PVDF/PI separator are superior to those of commercial polyolefin separators at 476% and 3.46 mS cm −1 , respectively, resulting better battery performances in terms of impedance, discharge capacity and cycle life. Under high temperature treatments above 170 °C, the self-shutdown function of the PI/PVDF/PI has been observed within 10 minutes, which could serve as the safety mechanism to defend the thermal runaway issue of lithium ion batteries. The effects of heating temperature and different time on the morphologies of each layer and electrolyte uptake of the separator are characterized as well

Isotope separation process

International Nuclear Information System (INIS)

Cox, D.M.; Maas, E.T.

1982-01-01

Processes are disclosed for the separation of isotopes of an element comprising vaporizing uranyl compounds having the formula (UO2a2)n, where a is a monovalent anion and n in an integer from 2 to 4, the compounds having an isotopically shifted infrared absorption spectrum associated with uranyl ions containing said element which is to be separated, and then irradiating the uranyl compound with infrared radiation which is preferentially absorbed by a molecular vibration of uranyl ions of the compound containing a predetermined isotope of that element so that excited molecules of the compound are provided which are enriched in the molecules of the compound containing that predetermined isotope, thus enabling separation of these excited molecules. The processes disclosed include separation of the excited molecules by irradiating under conditions such that the excited molecules dissociate, and also separating the excited molecules by a discrete separation step. The latter includes irradiating the excited molecules by a second infrared laser in order to convert the excited molecules into a separable product, or also by chemically converting the excited molecules, preferably by reaction with a gaseous reactant

Study on Mechanical Properties of Barite Concrete under Impact Load

Science.gov (United States)

Chen, Z. F.; Cheng, K.; Wu, D.; Gan, Y. C.; Tao, Q. W.

2018-03-01

In order to research the mechanical properties of Barite concrete under impact load, a group of concrete compression tests was carried out under the impact load by using the drop test machine. A high-speed camera was used to record the failure process of the specimen during the impact process. The test results show that:with the increase of drop height, the loading rate, the peak load, the strain under peak load, the strain rate and the dynamic increase factor (DIF) all increase gradually. The ultimate tensile strain is close to each other, and the time of impact force decreases significantly, showing significant strain rate effect.

micro-mechanical experimental investigation and modelling of strain and damage of argillaceous rocks under combined hydric and mechanical loads

International Nuclear Information System (INIS)

Wang, L.

2012-01-01

The hydro-mechanical behavior of argillaceous rocks, which are possible host rocks for underground radioactive nuclear waste storage, is investigated by means of micro-mechanical experimental investigations and modellings. Strain fields at the micrometric scale of the composite structure of this rock, are measured by the combination of environmental scanning electron microscopy, in situ testing and digital image correlation technique. The evolution of argillaceous rocks under pure hydric loading is first investigated. The strain field is strongly heterogeneous and manifests anisotropy. The observed nonlinear deformation at high relative humidity (RH) is related not only to damage, but also to the nonlinear swelling of the clay mineral itself, controlled by different local mechanisms depending on RH. Irreversible deformations are observed during hydric cycles, as well as a network of microcracks located in the bulk of the clay matrix and/or at the inclusion-matrix interface. Second, the local deformation field of the material under combined hydric and mechanical loadings is quantified. Three types of deformation bands are evidenced under mechanical loading, either normal to stress direction (compaction), parallel (microcracking) or inclined (shear). Moreover, they are strongly controlled by the water content of the material: shear bands are in particular prone to appear at high RH states. In view of understanding the mechanical interactions a local scale, the material is modeled as a composite made of non-swelling elastic inclusions embedded in an elastic swelling clay matrix. The internal stress field induced by swelling strain incompatibilities between inclusions and matrix, as well as the overall deformation, is numerically computed at equilibrium but also during the transient stage associated with a moisture gradient. An analytical micro-mechanical model based on Eshelby's solution is proposed. In addition, 2D finite element computations are performed. Results

Progressive damage analysis of carbon/epoxy laminates under couple laser and mechanical loading

Directory of Open Access Journals (Sweden)

Wanlei Liu

Full Text Available A multiscale model based bridge theory is proposed for the progressive damage analysis of carbon/epoxy laminates under couple laser and mechanical loading. The ablation model is adopted to calculate ablation temperature changing and ablation surface degradation. The polynomial strengthening model of matrix is used to improve bridging model for reducing parameter input. Stiffness degradation methods of bridging model are also improved in order to analyze the stress redistribution more accurately when the damage occurs. Thermal-mechanical analyses of the composite plate are performed using the ABAQUS/Explicit program with the developed model implemented in the VUMAT. The simulation results show that this model can be used to proclaim the mesoscale damage mechanism of composite laminates under coupled loading. Keywords: Laser irradiation, Multiscale analysis, Bridge model, Thermal-mechanical

An NMDA Receptor-Dependent Mechanism Underlies Inhibitory Synapse Development

Directory of Open Access Journals (Sweden)

Xinglong Gu

2016-01-01

Full Text Available In the mammalian brain, GABAergic synaptic transmission provides inhibitory balance to glutamatergic excitatory drive and controls neuronal output. The molecular mechanisms underlying the development of GABAergic synapses remain largely unclear. Here, we report that NMDA-type ionotropic glutamate receptors (NMDARs in individual immature neurons are the upstream signaling molecules essential for GABAergic synapse development, which requires signaling via Calmodulin binding motif in the C0 domain of the NMDAR GluN1 subunit. Interestingly, in neurons lacking NMDARs, whereas GABAergic synaptic transmission is strongly reduced, the tonic inhibition mediated by extrasynaptic GABAA receptors is increased, suggesting a compensatory mechanism for the lack of synaptic inhibition. These results demonstrate a crucial role for NMDARs in specifying the development of inhibitory synapses, and suggest an important mechanism for controlling the establishment of the balance between synaptic excitation and inhibition in the developing brain.

Ndj1, a telomere-associated protein, regulates centrosome separation in budding yeast meiosis

Science.gov (United States)

Li, Ping; Shao, Yize; Jin, Hui

2015-01-01

Yeast centrosomes (called spindle pole bodies [SPBs]) remain cohesive for hours during meiotic G2 when recombination takes place. In contrast, SPBs separate within minutes after duplication in vegetative cells. We report here that Ndj1, a previously known meiosis-specific telomere-associated protein, is required for protecting SPB cohesion. Ndj1 localizes to the SPB but dissociates from it ∼16 min before SPB separation. Without Ndj1, meiotic SPBs lost cohesion prematurely, whereas overproduction of Ndj1 delayed SPB separation. When produced ectopically in vegetative cells, Ndj1 caused SPB separation defects and cell lethality. Localization of Ndj1 to the SPB depended on the SUN domain protein Mps3, and removal of the N terminus of Mps3 allowed SPB separation and suppressed the lethality of NDJ1-expressing vegetative cells. Finally, we show that Ndj1 forms oligomeric complexes with Mps3, and that the Polo-like kinase Cdc5 regulates Ndj1 protein stability and SPB separation. These findings reveal the underlying mechanism that coordinates yeast centrosome dynamics with meiotic telomere movement and cell cycle progression. PMID:25897084

Damage evolution of TBC system under in-phase thermo-mechanical tests

International Nuclear Information System (INIS)

Kitazawa, R.; Tanaka, M.; Kagawa, Y.; Liu, Y.F.

2010-01-01

In-phase thermo-mechanical tests (TMF) of EB-PVD Y 2 O 3 -ZrO 2 thermal barrier coating (TBC) system (8 wt% Y 2 O 3 -ZrO 2 /CoNiCrAlY/IN-738 substrate) were done under a through-the-thick-direction thermal gradient from TBC surface temperature at 1150 deg. C to substrate temperature at 1000 deg. C. Deformation and failure behaviors of the TBC system were observed at the macroscopic and microscopic scales and damage evolution of the system under in-phase thermo-mechanical test was discussed. Special attention was paid to TBC layer cracking, thermally grown oxide (TGO) layer formation and void formation in bond coat and substrate. Effect of TMF conditions on the damage evolution behaviors was also discussed.

Advanced power cycler with intelligent monitoring strategy of IGBT module under test

DEFF Research Database (Denmark)

Choi, U. M.; Blaabjerg, F.; Iannuzzo, F.

2017-01-01

and diode, which for the wear-out condition monitoring are presented. This advanced power cycler allows to perform power cycling test cost-effectively under conditions close to real power converter applications. In addition, an intelligent monitoring strategy for the separation of package-related wear......-out failure mechanisms has been proposed. By means of the proposed method, the wear-out failure mechanisms of an IGBT module can be separated without any additional efforts during the power cycling tests. The validity and effectiveness of the proposed monitoring strategy are also verified by experiments....

UKAEA underlying research programme annual report

International Nuclear Information System (INIS)

Mason, J.P.

1988-11-01

Work from all technical areas of the Authority's underlying research programme is described. This is typically in the form of an interim progress report for the year April 1987 to March 1988. The seventeen chapters report research into radiation damage, fracture studies, chemical effects at surfaces, surface physics and corrosion, fluid mechanics and heat transfer, nuclear studies, neutron beam studies, theoretical sciences, instrumentation, reactor physics and control, fabrication processes, laser isotope separation, nuclear fuel cycle studies, quantum electronics, radiological protection, and miscellaneous underlying research. (author)

X-RAYS SEPARATOR: FORWARD STEP IN TECHNOLOGY OF OPTICAL SEPARATION

Directory of Open Access Journals (Sweden)

N. N. Potrakhov

2017-01-01

Full Text Available Presently the X-ray separation is used not only for research program, but it is also elaborated and applied for different sectors of economy. The seeds as biological objects that possess the complicated microstructure are very difficult to be exanimated by x-ray technology. The application of x-rays and further elaboration of optical  separators, principle  of action, basic specifications, way of their use and their efficiency was shown in the article. The x-ray separator may distinguish all hidden seed defects as it was described by a programmer, where owing to the use of the optical separating block in visual range it is possible to add some more details as a shape, brightness and a color of object surface being exanimated. The elaboration of such separation equipment is scientifically hard work requiring time and expenses. Last year researchers of ‘LETI’ developed the working model of industrial x-ray separator for examination of grains and nuts in different crops. This model was made on the basis of photoseparator F-5 manufactured at OAO ‘Voronezhselmash’. The instrument state and its mechanism operation are highlighted on monitor. In the regime of processing (separation and examination of each controlled batch, the passport is produced with  following  information on identification  code,  time of material receiving, time of test passed, number of grains or seeds tested. The code of receiver of material is given to each of established characteristics when working the regime of separation, determination of number of objects with characteristics tested and number of unidentified objects. The application of x-ray separators constructed on the basis of photoseparator F-5 enables to carry out the complex estimation on seed quality and separation in only instrument with the development of electronic protocol with many characteristics.

Mechanical properties of graphene nanoribbons under uniaxial tensile strain

Science.gov (United States)

Yoneyama, Kazufumi; Yamanaka, Ayaka; Okada, Susumu

2018-03-01

Based on the density functional theory with the generalized gradient approximation, we investigated the mechanical properties of graphene nanoribbons in terms of their edge shape under a uniaxial tensile strain. The nanoribbons with armchair and zigzag edges retain their structure under a large tensile strain, while the nanoribbons with chiral edges are fragile against the tensile strain compared with those with armchair and zigzag edges. The fracture started at the cove region, which corresponds to the border between the zigzag and armchair edges for the nanoribbons with chiral edges. For the nanoribbons with armchair edges, the fracture started at one of the cove regions at the edges. In contrast, the fracture started at the inner region of the nanoribbons with zigzag edges. The bond elongation under the tensile strain depends on the mutual arrangement of covalent bonds with respect to the strain direction.

About the notion of truth in quantum mechanics

International Nuclear Information System (INIS)

Omnes, R.

1991-01-01

The meaning of truth in quantum mechanics is considered in order to respond to some objections raised by B. d'Espagnat against a logical interpretation of quantum mechanics recently proposed by the author. A complete answer is given. It is shown that not only can factual data be said to be true, but also some of their logical consequences, so that the definition of truth given by Heisenberg is both extended and refined. Some nontrue but reliable propositions may also be used, but they are somewhat arbitrary because of the complementarity principle. For instance, the propositions expressing wave packet reduction can be either true or reliable, according to the case under study. Separability is also discussed: as far as the true properties of an individual system are concerned, quantum mechanics is separable

Mechanical Design of AM Fabricated Prismatic Rods under Torsion

Directory of Open Access Journals (Sweden)

Manzhirov Alexander V.

2017-01-01

Full Text Available We study the stress-strain state of viscoelastic prismatic rods fabricated or repaired by additive manufacturing technologies under torsion. An adequate description of the processes involved is given by methods of a new scientific field, mechanics of growing solids. Three main stages of the deformation process (before the beginning of growth, in the course of growth, and after the termination of growth are studied. Two versions of statement of two problems are given: (i given the torque, find the stresses, displacements, and torsion; (ii given the torsion, find the stresses, displacements, and torque. Solution methods using techniques of complex analysis are presented. The results can be used in mechanical and instrument engineering.

Mechanical and tribological behaviour of molten salt processed self-lubricated aluminium composite under different treatments

Science.gov (United States)

Kannan, C.; Ramanujam, R.

2018-05-01

The aim of this research work is to evaluate the mechanical and tribological behaviour of Al 7075 based self-lubricated hybrid nanocomposite under different treated conditions viz. as-cast, T6 and deep cryo treated. In order to overcome the drawbacks associated with conventional stir casting, a combinational approach that consists of molten salt processing, ultrasonic assistance and optimized mechanical stirring is adopted in this study to fabricate the nanocomposite. The mechanical characterisation tests carried out on this nanocomposite reveals an improvement of about 39% in hardness and 22% in ultimate tensile strength possible under T6 condition. Under specific conditions, the wear rate can be reduced to the extent of about 63% through the usage of self-lubricated hybrid nanocomposite under T6 condition.

Molecular mechanics of silk nanostructures under varied mechanical loading.

Science.gov (United States)

Bratzel, Graham; Buehler, Markus J

2012-06-01

Spider dragline silk is a self-assembling tunable protein composite fiber that rivals many engineering fibers in tensile strength, extensibility, and toughness, making it one of the most versatile biocompatible materials and most inviting for synthetic mimicry. While experimental studies have shown that the peptide sequence and molecular structure of silk have a direct influence on the stiffness, toughness, and failure strength of silk, few molecular-level analyses of the nanostructure of silk assemblies, in particular, under variations of genetic sequences have been reported. In this study, atomistic-level structures of wildtype as well as modified MaSp1 protein from the Nephila clavipes spider dragline silk sequences, obtained using an in silico approach based on replica exchange molecular dynamics and explicit water molecular dynamics, are subjected to simulated nanomechanical testing using different force-control loading conditions including stretch, pull-out, and peel. The authors have explored the effects of the poly-alanine length of the N. clavipes MaSp1 peptide sequence and identify differences in nanomechanical loading conditions on the behavior of a unit cell of 15 strands with 840-990 total residues used to represent a cross-linking β-sheet crystal node in the network within a fibril of the dragline silk thread. The specific loading condition used, representing concepts derived from the protein network connectivity at larger scales, have a significant effect on the mechanical behavior. Our analysis incorporates stretching, pull-out, and peel testing to connect biochemical features to mechanical behavior. The method used in this study could find broad applications in de novo design of silk-like tunable materials for an array of applications. Copyright © 2011 Wiley Periodicals, Inc.

Temporomandibular disorders and painful comorbidities: clinical association and underlying mechanisms.

Science.gov (United States)

Costa, Yuri Martins; Conti, Paulo César Rodrigues; de Faria, Flavio Augusto Cardoso; Bonjardim, Leonardo Rigoldi

2017-03-01

The association between temporomandibular disorders (TMDs) and headaches, cervical spine dysfunction, and fibromyalgia is not artefactual. The aim of this review is to describe the comorbid relationship between TMD and these three major painful conditions and to discuss the clinical implications and the underlying pain mechanisms involved in these relationships. Common neuronal pathways and central sensitization processes are acknowledged as the main factors for the association between TMD and primary headaches, although the establishment of cause-effect mechanisms requires further clarification and characterization. The biomechanical aspects are not the main factors involved in the comorbid relationship between TMD and cervical spine dysfunction, which can be better explained by the neuronal convergence of the trigeminal and cervical spine sensory pathways as well as by central sensitization processes. The association between TMD and fibromyalgia also has supporting evidence in the literature, and the proposed main mechanism underlying this relationship is the impairment of the descending pain inhibitory system. In this particular scenario, a cause-effect relationship is more likely to occur in one direction, that is, fibromyalgia as a risk factor for TMD. Therefore, clinical awareness of the association between TMD and painful comorbidities and the support of multidisciplinary approaches are required to recognize these related conditions. Copyright © 2016 Elsevier Inc. All rights reserved.

Carbon Footprint Management of Road Freight Transport under the Carbon Emission Trading Mechanism

Directory of Open Access Journals (Sweden)

Jin Li

2015-01-01

Full Text Available Growing concern over environmental issues has considerably increased the number of regulations and legislation that aim to curb carbon emissions. Carbon emission trading mechanism, which is one of the most effective means, has been broadly adopted by several countries. This paper presents a road truck routing problem under the carbon emission trading mechanism. By introducing a calculation method of carbon emissions that considers the load and speed of the vehicle among other factors, a road truck routing optimizing model under the cap and trade mechanism based on the Travelling Salesman Problem (TSP is described. Compared with the classical TSP model that only considers the economic cost, this model suggests that the truck routing decision under the cap and trade mechanism is more effective in reducing carbon emissions. A modified tabu search algorithm is also proposed to obtain solutions within a reasonable amount of computation time. We theoretically and numerically examine the impacts of carbon trading, carbon cap, and carbon price on truck routing decision, carbon emissions, and total cost. From the results of numerical experiments, we derive interesting observations about how to control the total cost and reduce carbon emissions.

Two distinct neural mechanisms underlying indirect reciprocity.

Science.gov (United States)

Watanabe, Takamitsu; Takezawa, Masanori; Nakawake, Yo; Kunimatsu, Akira; Yamasue, Hidenori; Nakamura, Mitsuhiro; Miyashita, Yasushi; Masuda, Naoki

2014-03-18

Cooperation is a hallmark of human society. Humans often cooperate with strangers even if they will not meet each other again. This so-called indirect reciprocity enables large-scale cooperation among nonkin and can occur based on a reputation mechanism or as a succession of pay-it-forward behavior. Here, we provide the functional and anatomical neural evidence for two distinct mechanisms governing the two types of indirect reciprocity. Cooperation occurring as reputation-based reciprocity specifically recruited the precuneus, a region associated with self-centered cognition. During such cooperative behavior, the precuneus was functionally connected with the caudate, a region linking rewards to behavior. Furthermore, the precuneus of a cooperative subject had a strong resting-state functional connectivity (rsFC) with the caudate and a large gray matter volume. In contrast, pay-it-forward reciprocity recruited the anterior insula (AI), a brain region associated with affective empathy. The AI was functionally connected with the caudate during cooperation occurring as pay-it-forward reciprocity, and its gray matter volume and rsFC with the caudate predicted the tendency of such cooperation. The revealed difference is consistent with the existing results of evolutionary game theory: although reputation-based indirect reciprocity robustly evolves as a self-interested behavior in theory, pay-it-forward indirect reciprocity does not on its own. The present study provides neural mechanisms underlying indirect reciprocity and suggests that pay-it-forward reciprocity may not occur as myopic profit maximization but elicit emotional rewards.

Charge separation at disordered semiconductor heterojunctions from random walk numerical simulations.

Science.gov (United States)

Mandujano-Ramírez, Humberto J; González-Vázquez, José P; Oskam, Gerko; Dittrich, Thomas; Garcia-Belmonte, Germa; Mora-Seró, Iván; Bisquert, Juan; Anta, Juan A

2014-03-07

Many recent advances in novel solar cell technologies are based on charge separation in disordered semiconductor heterojunctions. In this work we use the Random Walk Numerical Simulation (RWNS) method to model the dynamics of electrons and holes in two disordered semiconductors in contact. Miller-Abrahams hopping rates and a tunnelling distance-dependent electron-hole annihilation mechanism are used to model transport and recombination, respectively. To test the validity of the model, three numerical "experiments" have been devised: (1) in the absence of constant illumination, charge separation has been quantified by computing surface photovoltage (SPV) transients. (2) By applying a continuous generation of electron-hole pairs, the model can be used to simulate a solar cell under steady-state conditions. This has been exploited to calculate open-circuit voltages and recombination currents for an archetypical bulk heterojunction solar cell (BHJ). (3) The calculations have been extended to nanostructured solar cells with inorganic sensitizers to study, specifically, non-ideality in the recombination rate. The RWNS model in combination with exponential disorder and an activated tunnelling mechanism for transport and recombination is shown to reproduce correctly charge separation parameters in these three "experiments". This provides a theoretical basis to study relevant features of novel solar cell technologies.

Dynamical mechanism of charge separation by photoexcited generation of proton–electron pairs in organic molecular systems. A nonadiabatic electron wavepacket dynamics study

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Kentaro, E-mail: kyamamoto@fukui.kyoto-u.ac.jp; Takatsuka, Kazuo, E-mail: kaztak@fukui.kyoto-u.ac.jp

2016-08-22

Graphical abstract: Asymptotic biradical state produced by the excited-state coupled proton–electron transfer (CPET), resulting in charge separation (proton–electron pair creation) on a proton–electron acceptor A, in a series of photochemical systems generally denoted as X–Mn–OH{sub 2}⋯A, where X = (OH, Ca(OH){sub 3}) and A = (N-methylformamidine, guanidine, imidazole, or ammonia clusters). - Abstract: In this perspective article, we review, along with presenting new results, a series of our theoretical analyses on the excited-state mechanism of charge separation (proton–electron pair creation) relevant to the photoinduced water-splitting reaction (2H{sub 2}O → 4H{sup +} + 4e{sup −} + O{sub 2}) in organic and biological systems, which quite often includes Mn clusters in various molecular configurations. The present mechanism is conceived to be universal in the triggering process of the photoexcited water splitting dynamics. In other words, any Mn-based catalytic charge separation is quite likely to be initiated according to this mechanism. As computationally tractable yet realistic models, we examine a series of systems generally expressed as X–Mn–OH{sub 2}⋯A, where X = (OH, Ca(OH){sub 3}) and A = (N-methylformamidine, guanidine, imidazole or ammonia cluster) in terms of the theory of nonadiabatic electron wavepacket dynamics. We first find both an electron and a proton are simultaneously transferred to the acceptors through conical intersections upon photoexcitation. In this mechanism, the electron takes different pathways from that of the proton and reaches the densely lying Rydberg-like states of the acceptors in the end, thereby inducing charge separation. Therefore the presence of the Rydberg-like diffused unoccupied states as an electron acceptor is critical for this reaction to proceed. We also have found another crucial nonadiabatic process that deteriorates the efficiency of charge separation by rendering the created pair of proton

Cavitation behavior observed in three monoleaflet mechanical heart valves under accelerated testing conditions.

Science.gov (United States)

Lo, Chi-Wen; Liu, Jia-Shing; Li, Chi-Pei; Lu, Po-Chien; Hwang, Ned H

2008-01-01

Accelerated testing provides a substantial amount of data on mechanical heart valve durability in a short period of time, but such conditions may not accurately reflect in vivo performance. Cavitation, which occurs during mechanical heart valve closure when local flow field pressure decreases below vapor pressure, is thought to play a role in valve damage under accelerated conditions. The underlying flow dynamics and mechanisms behind cavitation bubble formation are poorly understood. Under physiologic conditions, random perivalvular cavitation is difficult to capture. We applied accelerated testing at a pulse rate of 600 bpm and transvalvular pressure of 120 mm Hg, with synchronized videographs and high-frequency pressure measurements, to study cavitation of the Medtronic Hall Standard (MHS), Medtronic Hall D-16 (MHD), and Omni Carbon (OC) valves. Results showed cavitation bubbles between 340 and 360 micros after leaflet/housing impact of the MHS, MHD, and OC valves, intensified by significant leaflet rebound. Squeeze flow, Venturi, and water hammer effects each contributed to cavitation, depending on valve design.

Mechanisms underlying KCNQ1channel cell volume sensitivity

DEFF Research Database (Denmark)

Hammami, Sofia

Cells are constantly exposed to changes in cell volume during cell metabolism, nutrient uptake, cell proliferation, cell migration and salt and water transport. In order to cope with these perturbations, potassium channels in line with chloride channels have been shown to be likely contributors...... to the process of cell volume adjustments. A great diversity of potassium channels being members of either the 6TM, 4 TM or 2 TM K+ channel gene family have been shown to be strictly regulated by small, fast changes in cell volume. However, the precise mechanism underlying the K+ channel sensitivity to cell...... volume alterations is not yet fully understood. The KCNQ1 channel belonging to the voltage gated KCNQ family is considered a precise sensor of volume changes. The goal of this thesis was to elucidate the mechanism that induces cell volume sensitivity. Until now, a number of investigators have implicitly...

Redox‐Active Separators for Lithium‐Ion Batteries

Science.gov (United States)

Pan, Ruijun; Ruan, Changqing; Edström, Kristina; Strømme, Maria

2017-01-01

Abstract A bilayered cellulose‐based separator design is presented that can enhance the electrochemical performance of lithium‐ion batteries (LIBs) via the inclusion of a porous redox‐active layer. The proposed flexible redox‐active separator consists of a mesoporous, insulating nanocellulose fiber layer that provides the necessary insulation between the electrodes and a porous, conductive, and redox‐active polypyrrole‐nanocellulose layer. The latter layer provides mechanical support to the nanocellulose layer and adds extra capacity to the LIBs. The redox‐active separator is mechanically flexible, and no internal short circuits are observed during the operation of the LIBs, even when the redox‐active layer is in direct contact with both electrodes in a symmetric lithium–lithium cell. By replacing a conventional polyethylene separator with a redox‐active separator, the capacity of the proof‐of‐concept LIB battery containing a LiFePO4 cathode and a Li metal anode can be increased from 0.16 to 0.276 mA h due to the capacity contribution from the redox‐active separator. As the presented redox‐active separator concept can be used to increase the capacities of electrochemical energy storage systems, this approach may pave the way for new types of functional separators. PMID:29593967

Crack formation and crack propagation under multiaxial mechanical and thermal stresses. Proceedings

International Nuclear Information System (INIS)

1993-01-01

The 25th meeting of the DV Fracture Group was held on 16/17 February 1993 at Karlsruhe Technical University. The main topic, ''Crack formation and crack propagation under multiaxial mechanical and thermal stresses'', was discussed by five invited papers (by K.J. Miller, D. Loehe, H.A. Richard, W. Brocks, A. Brueckner-Foit) and 23 short papers. The other 21 papers were devoted to various domains of fracture mechanics, with emphasis on elastoplastic fracture mechanics. (orig./MM) [de

A mechanical deformation model of metallic fuel pin under steady state conditions

International Nuclear Information System (INIS)

Lee, D. W.; Lee, B. W.; Kim, Y. I.; Han, D. H.

2004-01-01

As a mechanical deformation model of the MACSIS code predicts the cladding deformation due to the simple thin shell theory, it is impossible to predict the FCMI(Fuel-Cladding Mechanical Interaction). Therefore, a mechanical deformation model used the generalized plane strain is developed. The DEFORM is a mechanical deformation routine which is used to analyze the stresses and strains in the fuel and cladding of a metallic fuel pin of LMRs. The accuracy of the program is demonstrated by comparison of the DEFORM predictions with the result of another code calculations or experimental results in literature. The stress/strain distributions of elastic part under free thermal expansion condition are completely matched with the results of ANSYS code. The swelling and creep solutions are reasonably well agreed with the simulations of ALFUS and LIFE-M codes, respectively. The predicted cladding strains are under estimated than experimental data at the range of high burnup. Therefore, it is recommended that the fine tuning of the DEFORM based on various range of experimental data

Graphene supported silver@silver chloride & ferroferric oxide hybrid, a magnetically separable photocatalyst with high performance under visible light irradiation

Energy Technology Data Exchange (ETDEWEB)

Zhong, Suting; Jiang, Wei, E-mail: superfine_jw@126.com; Han, Mei; Liu, Gongzong; Zhang, Na; Lu, Yue

2015-08-30

Graphical abstract: - Highlights: • The composites were synthesized via a facile and effective process. • Plenty of Fe{sub 3}O{sub 4} and Ag@AgCl nanoparticles are deposited on the reduced graphene oxide nanosheets. • The catalyst exhibited an enhanced photocatalytic performance and magnetic property. • The catalyst is stable under the visible light irradiation. - Abstract: A stable magnetic separable plasmonic photocatalyst was successfully fabricated by grafting silver@silver chloride (Ag@AgCl) and ferroferric oxide (Fe{sub 3}O{sub 4}) nanoparticles on graphene sheets. The composite exhibited high activity degrading methylene blue (MB) and rhodamine B (RB) under visible light irradiation: decomposition 97.4% of MB in 100 min and 97.9% of RB in 120 min. The enhanced photocatalytic activities can be attributed to synergistic effect between Ag@AgCl and graphene: the effective charge transfer from Ag@AgCl to graphene thus promotes the separation of electron–hole pairs. Moreover, the excellent magnetic property gives a more convenient way to recycle the photocatalysts.

Effect of applied strain on phase separation of Fe-28 at.% Cr alloy: 3D phase-field simulation

Science.gov (United States)

Zhu, Lihui; Li, Yongsheng; Liu, Chengwei; Chen, Shi; Shi, Shujing; Jin, Shengshun

2018-04-01

A quantitative simulation of the separation of the α‧ phase in Fe-28 at.% Cr alloy under the effects of applied strain is performed by utilizing a three-dimensional phase-field model. The elongation of the Cr-enriched α‧ phase becomes obvious with the influence of applied uniaxial strain for the phase separation transforms from spinodal decomposition of 700 K to nucleation and growth of 773 K. The applied strain shows a significant influence on the early stage phase separation, and the influence is enlarged with the elevated temperature. The steady-state coarsening with the mechanism of spinodal decomposition is substantially affected by the applied strain for low-temperature aging, while the influence is reduced as the temperature increases and as the phase separation mechanism changes to nucleation and growth. The peak value of particle size distribution decreases, and the PSD for 773 K becomes more widely influenced by the applied strain. The simulation results of separation of the Cr-enriched α‧ phase with the applied strain provide a further understanding of the strain effect on the phase separation of Fe-Cr alloys from the metastable region to spinodal regions.

Damage evolution of TBC system under in-phase thermo-mechanical tests

Energy Technology Data Exchange (ETDEWEB)

Kitazawa, R.; Tanaka, M.; Kagawa, Y. [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan); Liu, Y.F., E-mail: yfliu@hyper.rcast.u-tokyo.ac.jp [Research Center for Advanced Science and Technology, University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904 (Japan)

2010-10-15

In-phase thermo-mechanical tests (TMF) of EB-PVD Y{sub 2}O{sub 3}-ZrO{sub 2} thermal barrier coating (TBC) system (8 wt% Y{sub 2}O{sub 3}-ZrO{sub 2}/CoNiCrAlY/IN-738 substrate) were done under a through-the-thick-direction thermal gradient from TBC surface temperature at 1150 deg. C to substrate temperature at 1000 deg. C. Deformation and failure behaviors of the TBC system were observed at the macroscopic and microscopic scales and damage evolution of the system under in-phase thermo-mechanical test was discussed. Special attention was paid to TBC layer cracking, thermally grown oxide (TGO) layer formation and void formation in bond coat and substrate. Effect of TMF conditions on the damage evolution behaviors was also discussed.

Separation techniques: Chromatography

Science.gov (United States)

Coskun, Ozlem

2016-01-01

Chromatography is an important biophysical technique that enables the separation, identification, and purification of the components of a mixture for qualitative and quantitative analysis. Proteins can be purified based on characteristics such as size and shape, total charge, hydrophobic groups present on the surface, and binding capacity with the stationary phase. Four separation techniques based on molecular characteristics and interaction type use mechanisms of ion exchange, surface adsorption, partition, and size exclusion. Other chromatography techniques are based on the stationary bed, including column, thin layer, and paper chromatography. Column chromatography is one of the most common methods of protein purification. PMID:28058406

Closed compact Taylor's droplets in a phase-separated lamellar-sponge mixture under shear flow

Science.gov (United States)

Courbin, L.; Cristobal, G.; Rouch, J.; Panizza, P.

2001-09-01

We have studied by optical microscopy, small-angle light scattering, and rheology, the behavior under shear flow of a phase-separated lamellar-sponge (Lα - L3) ternary mixture. We observe in the Lα-rich region (ΦLα > 80%) the existence of a Newtonian assembly made of closed compact monodisperse lamellar droplets immersed in the sponge phase. Contrary to the classical onion glassy texture obtained upon shearing Lα phases, the droplet size scales herein as dot gamma-1, the inverse of the shear rate. This result is in good agreement with Taylor's picture. Above a critical shear rate, dot gammac, the droplets organize to form a single colloidal crystal whose lattice size varies as dot gamma-1/3. To the memory of Tess Melissa P.

Maternal separation increases later immobility during forced swim in guinea pig pups: evidence for sensitization of a depressive-like state.

Science.gov (United States)

Hennessy, Michael B; Schreibeis, Amanda D; Schiml, Patricia A; Deak, Terrence

2017-01-01

Early-life stress is thought to increase later vulnerability for developing depressive illness by sensitizing underlying stress-responsive systems. Guinea pig pups separated from their mother and isolated in a novel cage for 3 hr exhibit a sensitized depressive-like behavioral response when separated again the following day as well as weeks later. The behavioral response and its sensitization appear to be mediated by inflammatory factors. To determine if this sensitization is specific to the separation response or if it reflects a broader underlying depressive-like state, guinea pig pups that had either been separated for 3 hr or remained with their mothers were observed in the forced swim test the following 3 days. Earlier separation was found to increase the duration of immobility, a measure sensitive to antidepressant treatment. These results support the use of the guinea pig as a model for examining mechanisms of inflammatory-mediated sensitization of depression following stress in early life. © 2016 Wiley Periodicals, Inc.

Underlying mechanism in the water chemistry of nuclear systems

International Nuclear Information System (INIS)

Walton, G.N.

1978-01-01

The equilibrium between dissolved hydrogen and oxygen in the molecular decomposition of water, and the equilibrium between hydrogen ions and hydroxyl ions in the ionic dissociation of water, both constitute important underlying mechanisms in the corrosion behaviour of water. The two equilibria, and the rates of the reactions involved in water and steam, will be compared and contrasted as a function of temperature, pressure and radiation. The effects of the equilibria on the hydrolysis and solubility of ferrous and ferric ions, and the ions of other metals, will be discussed in relation to the control of conditions in the coolant circuits of nuclear reactors. A third mechanism to discussed is the electrochemical exchange reactions that can contribute to the contamination of circuits. (author)

Causal and causally separable processes

Science.gov (United States)

Oreshkov, Ognyan; Giarmatzi, Christina

2016-09-01

The idea that events are equipped with a partial causal order is central to our understanding of physics in the tested regimes: given two pointlike events A and B, either A is in the causal past of B, B is in the causal past of A, or A and B are space-like separated. Operationally, the meaning of these order relations corresponds to constraints on the possible correlations between experiments performed in the vicinities of the respective events: if A is in the causal past of B, an experimenter at A could signal to an experimenter at B but not the other way around, while if A and B are space-like separated, no signaling is possible in either direction. In the context of a concrete physical theory, the correlations compatible with a given causal configuration may obey further constraints. For instance, space-like correlations in quantum mechanics arise from local measurements on joint quantum states, while time-like correlations are established via quantum channels. Similarly to other variables, however, the causal order of a set of events could be random, and little is understood about the constraints that causality implies in this case. A main difficulty concerns the fact that the order of events can now generally depend on the operations performed at the locations of these events, since, for instance, an operation at A could influence the order in which B and C occur in A’s future. So far, no formal theory of causality compatible with such dynamical causal order has been developed. Apart from being of fundamental interest in the context of inferring causal relations, such a theory is imperative for understanding recent suggestions that the causal order of events in quantum mechanics can be indefinite. Here, we develop such a theory in the general multipartite case. Starting from a background-independent definition of causality, we derive an iteratively formulated canonical decomposition of multipartite causal correlations. For a fixed number of settings and

Causal and causally separable processes

International Nuclear Information System (INIS)

Oreshkov, Ognyan; Giarmatzi, Christina

2016-01-01

The idea that events are equipped with a partial causal order is central to our understanding of physics in the tested regimes: given two pointlike events A and B , either A is in the causal past of B , B is in the causal past of A , or A and B are space-like separated. Operationally, the meaning of these order relations corresponds to constraints on the possible correlations between experiments performed in the vicinities of the respective events: if A is in the causal past of B , an experimenter at A could signal to an experimenter at B but not the other way around, while if A and B are space-like separated, no signaling is possible in either direction. In the context of a concrete physical theory, the correlations compatible with a given causal configuration may obey further constraints. For instance, space-like correlations in quantum mechanics arise from local measurements on joint quantum states, while time-like correlations are established via quantum channels. Similarly to other variables, however, the causal order of a set of events could be random, and little is understood about the constraints that causality implies in this case. A main difficulty concerns the fact that the order of events can now generally depend on the operations performed at the locations of these events, since, for instance, an operation at A could influence the order in which B and C occur in A ’s future. So far, no formal theory of causality compatible with such dynamical causal order has been developed. Apart from being of fundamental interest in the context of inferring causal relations, such a theory is imperative for understanding recent suggestions that the causal order of events in quantum mechanics can be indefinite. Here, we develop such a theory in the general multipartite case. Starting from a background-independent definition of causality, we derive an iteratively formulated canonical decomposition of multipartite causal correlations. For a fixed number of settings and

Performance and separation occurrence of binary probit regression estimator using maximum likelihood method and Firths approach under different sample size

Science.gov (United States)

Lusiana, Evellin Dewi

2017-12-01

The parameters of binary probit regression model are commonly estimated by using Maximum Likelihood Estimation (MLE) method. However, MLE method has limitation if the binary data contains separation. Separation is the condition where there are one or several independent variables that exactly grouped the categories in binary response. It will result the estimators of MLE method become non-convergent, so that they cannot be used in modeling. One of the effort to resolve the separation is using Firths approach instead. This research has two aims. First, to identify the chance of separation occurrence in binary probit regression model between MLE method and Firths approach. Second, to compare the performance of binary probit regression model estimator that obtained by MLE method and Firths approach using RMSE criteria. Those are performed using simulation method and under different sample size. The results showed that the chance of separation occurrence in MLE method for small sample size is higher than Firths approach. On the other hand, for larger sample size, the probability decreased and relatively identic between MLE method and Firths approach. Meanwhile, Firths estimators have smaller RMSE than MLEs especially for smaller sample sizes. But for larger sample sizes, the RMSEs are not much different. It means that Firths estimators outperformed MLE estimator.

Music and Memory in Alzheimer's Disease and The Potential Underlying Mechanisms.

Science.gov (United States)

Peck, Katlyn J; Girard, Todd A; Russo, Frank A; Fiocco, Alexandra J

2016-01-01

With population aging and a projected exponential expansion of persons diagnosed with Alzheimer's disease (AD), the development of treatment and prevention programs has become a fervent area of research and discovery. A growing body of evidence suggests that music exposure can enhance memory and emotional function in persons with AD. However, there is a paucity of research that aims to identify specific underlying neural mechanisms associated with music's beneficial effects in this particular population. As such, this paper reviews existing anecdotal and empirical evidence related to the enhancing effects of music exposure on cognitive function and further provides a discussion on the potential underlying mechanisms that may explain music's beneficial effect. Specifically, this paper will outline the potential role of the dopaminergic system, the autonomic nervous system, and the default network in explaining how music may enhance memory function in persons with AD.

Plant-insect interactions under bacterial influence: ecological implications and underlying mechanisms.

Science.gov (United States)

Sugio, Akiko; Dubreuil, Géraldine; Giron, David; Simon, Jean-Christophe

2015-02-01

Plants and insects have been co-existing for more than 400 million years, leading to intimate and complex relationships. Throughout their own evolutionary history, plants and insects have also established intricate and very diverse relationships with microbial associates. Studies in recent years have revealed plant- or insect-associated microbes to be instrumental in plant-insect interactions, with important implications for plant defences and plant utilization by insects. Microbial communities associated with plants are rich in diversity, and their structure greatly differs between below- and above-ground levels. Microbial communities associated with insect herbivores generally present a lower diversity and can reside in different body parts of their hosts including bacteriocytes, haemolymph, gut, and salivary glands. Acquisition of microbial communities by vertical or horizontal transmission and possible genetic exchanges through lateral transfer could strongly impact on the host insect or plant fitness by conferring adaptations to new habitats. Recent developments in sequencing technologies and molecular tools have dramatically enhanced opportunities to characterize the microbial diversity associated with plants and insects and have unveiled some of the mechanisms by which symbionts modulate plant-insect interactions. Here, we focus on the diversity and ecological consequences of bacterial communities associated with plants and herbivorous insects. We also highlight the known mechanisms by which these microbes interfere with plant-insect interactions. Revealing such mechanisms in model systems under controlled environments but also in more natural ecological settings will help us to understand the evolution of complex multitrophic interactions in which plants, herbivorous insects, and micro-organisms are inserted. © The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions

Separate mechanisms for magnitude and order processing in the spatial-numerical association of response codes (SNARC) effect: The strange case of musical note values.

Science.gov (United States)

Prpic, Valter; Fumarola, Antonia; De Tommaso, Matteo; Luccio, Riccardo; Murgia, Mauro; Agostini, Tiziano

2016-08-01

The spatial-numerical association of response codes (SNARC) effect is considered an evidence of the association between numbers and space, with faster left key-press responses to small numbers and faster right key-press responses to large numbers. We examined whether visually presented note values produce a SNARC-like effect. Differently from numbers, note values are represented as a decreasing left-to-right progression, allowing us to disambiguate the contribution of order and magnitude in determining the direction of the effect. Musicians with formal education performed a note value comparison in Experiment 1 (direct task), a line orientation judgment in Experiment 2 (indirect task), and a detection task in Experiment 3 (indirect task). When note values were task relevant (direct task), participants responded faster to large note values with the left key-press, and vice versa. Conversely, when note values were task irrelevant (indirect tasks), the direction of this association was reversed. This evidence suggests the existence of separate mechanisms underlying the SNARC effect. Namely, an Order-Related Mechanism (ORM) and a Magnitude-Related Mechanism (MRM) that are revealed by different task demands. Indeed, according to a new model we proposed, ordinal and magnitude related information appears to be preferentially involved in direct and indirect tasks, respectively. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Insights into the Mechanisms Underlying Boron Homeostasis in Plants

Directory of Open Access Journals (Sweden)

Akira Yoshinari

2017-11-01

Full Text Available Boron is an essential element for plants but is toxic in excess. Therefore, plants must adapt to both limiting and excess boron conditions for normal growth. Boron transport in plants is primarily based on three transport mechanisms across the plasma membrane: passive diffusion of boric acid, facilitated diffusion of boric acid via channels, and export of borate anion via transporters. Under boron -limiting conditions, boric acid channels and borate exporters function in the uptake and translocation of boron to support growth of various plant species. In Arabidopsis thaliana, NIP5;1 and BOR1 are located in the plasma membrane and polarized toward soil and stele, respectively, in various root cells, for efficient transport of boron from the soil to the stele. Importantly, sufficient levels of boron induce downregulation of NIP5;1 and BOR1 through mRNA degradation and proteolysis through endocytosis, respectively. In addition, borate exporters, such as Arabidopsis BOR4 and barley Bot1, function in boron exclusion from tissues and cells under conditions of excess boron. Thus, plants actively regulate intracellular localization and abundance of transport proteins to maintain boron homeostasis. In this review, the physiological roles and regulatory mechanisms of intracellular localization and abundance of boron transport proteins are discussed.

Phase separation and mechanical properties of an elastomeric biomaterial from spider wrapping silk and elastin block copolymers.

Science.gov (United States)

Muiznieks, Lisa D; Keeley, Fred W

2016-10-01

Elastin and silk spidroins are fibrous, structural proteins with elastomeric properties of extension and recoil. While elastin is highly extensible and has excellent recovery of elastic energy, silks are particularly strong and tough. This study describes the biophysical characterization of recombinant polypeptides designed by combining spider wrapping silk and elastin-like sequences as a strategy to rationally increase the strength of elastin-based materials while maintaining extensibility. We demonstrate a thermo-responsive phase separation and spontaneous colloid-like droplet formation from silk-elastin block copolymers, and from a 34 residue disordered region of Argiope trifasciata wrapping silk alone, and measure a comprehensive suite of tensile mechanical properties from cross-linked materials. Silk-elastin materials exhibited significantly increased strength, toughness, and stiffness compared to an elastin-only material, while retaining high failure strains and low energy loss upon recoil. These data demonstrate the mechanical tunability of protein polymer biomaterials through modular, chimeric recombination, and provide structural insights into mechanical design. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 693-703, 2016. © 2016 Wiley Periodicals, Inc.

PHYSIOLOGICAL QUALITY OF SOYBEAN SEEDS UNDER MECHANICAL INJURIES CAUSED BY COMBINES

OpenAIRE

FÁBIO PALCZEWSKI PACHECO; LÚCIA HELENA PEREIRA NÓBREGA; GISLAINE PICOLLO DE LIMA; MÁRCIA SANTORUM; WALTER BOLLER; LORIVAN FORMIGHIERI

2015-01-01

The mechanical harvesting causes injuries on seeds and may affect their quality. Different threshing mechanisms and their adjustments may also affect the intensity of impacts that machines cause on seeds. So, this study aimed at diagnosing and evaluating the effect of two combines: the first one with a threshing system of axial flow and the other one with a threshing system of tangential flow, under adjustments of concave opening (10 mm, 30 mm and 10 mm for a combine with axial ...

Short range order and phase separation in Ti-rich Ti-Al alloys

International Nuclear Information System (INIS)

Liew, H.J.

1999-01-01

Many metals and alloys are used in service under conditions in which they are metastable or unstable with respect to phase separation or transformation. Analytical and numerical models exist for relatively simple decomposition processes, such as nucleation and growth mechanisms and spinodal decomposition. In reality, however, more complex phase transformations may occur which are less well understood. For example, reactions involving coupled ordering and phase separation, such as the 'conditional spinodal mechanism', have been predicted. A 'conditional spinodal' is defined as a reaction in which compositional phase separation is thermodynamically possible only after a prior process, such as ordering at the parent composition. There is some debate regarding which real alloy systems exhibit such complex behaviour. Previous atom probe field ion microscopy work on titanium-rich titanium-aluminium based alloys has led to the suggestion that formation of the α 2 phase in this system may occur by a complex phase separation process. As well as being of interest from the point of view of fundamental materials science, this has potential engineering significance as the Ti-Al system forms the basis of the current generation of high-temperature Ti-based alloys for compressor applications in jet engines. This thesis describes an investigation into the phase decomposition process taking place in a titanium-rich Ti-Al alloy lying in the two-phase α+α 2 region. Experimentally, a binary alloy containing 15at% aluminium was heat-treated and examined using electron microscopy, X-ray diffraction, atom probe field ion microscopy and mechanical testing methods. Neutron diffraction experiments were also completed on this system for the first time. In addition, fully three-dimensional atomistic simulations were conducted using a Monte Carlo computer model based on first principles thermodynamic stability calculations of the Ti-Al system. The results provide an insight into many aspects

Frictional behaviour of polymer films under mechanical and electrostatic loads

International Nuclear Information System (INIS)

Ginés, R; Christen, R; Motavalli, M; Bergamini, A; Ermanni, P

2013-01-01

Different polymer foils, namely polyimide, FEP, PFA and PVDF were tested on a setup designed to measure the static coefficient of friction between them. The setup was designed according to the requirements of a damping device based on electrostatically tunable friction. The foils were tested under different mechanically applied forces and showed reproducible results for the static coefficient of friction. With the same setup the measurements were performed under an electric field as the source of the normal force. Up to a certain electric field the values were in good agreement. Beyond this field discrepancies were found. (paper)

Structural Changes of PVDF Membranes by Phase Separation Control

International Nuclear Information System (INIS)

Lee, Semin; Kim, Sung Soo

2016-01-01

Thermally induced phase separation (TIPS) and nonsolvent induced phase separation (NIPS) were simultaneously induced for the preparation of flat PVDF membranes. N-methyl-2-pyrrolidone (NMP) was used as a solvent and dibutyl-phthlate (DBP) was used as a diluent for PVDF. When PVDF was melt blended with NMP and DBP, crystallization temperature was lowered for TIPS and unstable region was expanded for NIPS. Ratio of solvent to diluent changed the phase separation mechanism to obtain the various membrane structures. Contact mode of dope solution with nonsolvent determined the dominant phase separation behavior. Since heat transfer rate was greater than mass transfer rate, surface structure was formed by NIPS and inner structure was by TIPS. Quenching temperature of dope solution also affected the phase separation mechanism and phase separation rate to result in the variation of structure

Failure mechanism of monolayer graphene under hypervelocity impact of spherical projectile

Science.gov (United States)

Xia, Kang; Zhan, Haifei; Hu, De'An; Gu, Yuantong

2016-09-01

The excellent mechanical properties of graphene have enabled it as appealing candidate in the field of impact protection or protective shield. By considering a monolayer graphene membrane, in this work, we assessed its deformation mechanisms under hypervelocity impact (from 2 to 6 km/s), based on a serial of in silico studies. It is found that the cracks are formed preferentially in the zigzag directions which are consistent with that observed from tensile deformation. Specifically, the boundary condition is found to exert an obvious influence on the stress distribution and transmission during the impact process, which eventually influences the penetration energy and crack growth. For similar sample size, the circular shape graphene possesses the best impact resistance, followed by hexagonal graphene membrane. Moreover, it is found the failure shape of graphene membrane has a strong relationship with the initial kinetic energy of the projectile. The higher kinetic energy, the more number the cracks. This study provides a fundamental understanding of the deformation mechanisms of monolayer graphene under impact, which is crucial in order to facilitate their emerging future applications for impact protection, such as protective shield from orbital debris for spacecraft.

Behavior of duplex stainless steel casting defects under mechanical loadings

Energy Technology Data Exchange (ETDEWEB)

Jayet-Gendrot, S [Electricite de France, 77 - Moret-sur-Loing (France). Dept. of Materials Study; Gilles, P; Migne, C [Societe Franco-Americaine de Constructions Atomiques (FRAMATOME), 92 - Paris-La-Defense (France)

1997-04-01

Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster`s envelope. The tests are analyzed in order to develop a method that takes into account the behavior of castings defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modelling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (author) 18 refs.

Nonlinear Mechanics of MEMS Rectangular Microplates under Electrostatic Actuation

KAUST Repository

Saghir, Shahid

2016-12-01

The first objective of the dissertation is to develop a suitable reduced order model capable of investigating the nonlinear mechanical behavior of von-Karman plates under electrostatic actuation. The second objective is to investigate the nonlinear static and dynamic behavior of rectangular microplates under small and large actuating forces. In the first part, we present and compare various approaches to develop reduced order models for the nonlinear von-Karman rectangular microplates actuated by nonlinear electrostatic forces. The reduced-order models aim to investigate the static and dynamic behavior of the plate under small and large actuation forces. A fully clamped microplate is considered. Different types of basis functions are used in conjunction with the Galerkin method to discretize the governing equations. First we investigate the convergence with the number of modes retained in the model. Then for validation purpose, a comparison of the static results is made with the results calculated by a nonlinear finite element model. The linear eigenvalue problem for the plate under the electrostatic force is solved for a wide range of voltages up to pull-in. In the second part, we present an investigation of the static and dynamic behavior of a fully clamped microplate. We investigate the effect of different non-dimensional design parameters on the static response. The forced-vibration response of the plate is then investigated when the plate is excited by a harmonic AC load superimposed to a DC load. The dynamic behavior is examined near the primary and secondary (superharmonic and subharmonic) resonances. The microplate shows a strong hardening behavior due to the cubic nonlinearity of midplane stretching. However, the behavior switches to softening as the DC load is increased. Next, near-square plates are studied to understand the effect of geometric imperfections of microplates. In the final part of the dissertation, we investigate the mechanical behavior of

Neural mechanisms underlying morphine withdrawal in addicted patients: a review

Directory of Open Access Journals (Sweden)

Nima Babhadiashar

2015-06-01

Full Text Available Morphine is one of the most potent alkaloid in opium, which has substantial medical uses and needs and it is the first active principle purified from herbal source. Morphine has commonly been used for relief of moderate to severe pain as it acts directly on the central nervous system; nonetheless, its chronic abuse increases tolerance and physical dependence, which is commonly known as opiate addiction. Morphine withdrawal syndrome is physiological and behavioral symptoms that stem from prolonged exposure to morphine. A majority of brain regions are hypofunctional over prolonged abstinence and acute morphine withdrawal. Furthermore, several neural mechanisms are likely to contribute to morphine withdrawal. The present review summarizes the literature pertaining to neural mechanisms underlying morphine withdrawal. Despite the fact that morphine withdrawal is a complex process, it is suggested that neural mechanisms play key roles in morphine withdrawal.

Interfacial separation of a mature biofilm from a glass surface - A combined experimental and cohesive zone modelling approach.

Science.gov (United States)

Safari, Ashkan; Tukovic, Zeljko; Cardiff, Philip; Walter, Maik; Casey, Eoin; Ivankovic, Alojz

2016-02-01

A good understanding of the mechanical stability of biofilms is essential for biofouling management, particularly when mechanical forces are used. Previous biofilm studies lack a damage-based theoretical model to describe the biofilm separation from a surface. The purpose of the current study was to investigate the interfacial separation of a mature biofilm from a rigid glass substrate using a combined experimental and numerical modelling approach. In the current work, the biofilm-glass interfacial separation process was investigated under tensile and shear stresses at the macroscale level, known as modes I and II failure mechanisms respectively. The numerical simulations were performed using a Finite Volume (FV)-based simulation package (OpenFOAM®) to predict the separation initiation using the cohesive zone model (CZM). Atomic force microscopy (AFM)-based retraction curve was used to obtain the separation properties between the biofilm and glass colloid at microscale level, where the CZM parameters were estimated using the Johnson-Kendall-Roberts (JKR) model. In this study CZM is introduced as a reliable method for the investigation of interfacial separation between a biofilm and rigid substrate, in which a high local stress at the interface edge acts as an ultimate stress at the crack tip.This study demonstrated that the total interfacial failure energy measured at the macroscale, was significantly higher than the pure interfacial separation energy obtained by AFM at the microscale, indicating a highly ductile deformation behaviour within the bulk biofilm matrix. The results of this study can significantly contribute to the understanding of biofilm detachments. Copyright © 2015 Elsevier Ltd. All rights reserved.

26 CFR 26.2654-1 - Certain trusts treated as separate trusts.

Science.gov (United States)

2010-04-01

... trusts under local law, treatment of a single trust as separate trusts under this paragraph (a)(1) does... applicable state law, then each resulting trust is treated as a separate trust for purposes of Chapter 13... Internal Revenue Code, if those portions are not treated as separate trusts under local law. Also...

Behavioral pattern separation and its link to the neural mechanisms of fear generalization.

Science.gov (United States)

Lange, Iris; Goossens, Liesbet; Michielse, Stijn; Bakker, Jindra; Lissek, Shmuel; Papalini, Silvia; Verhagen, Simone; Leibold, Nicole; Marcelis, Machteld; Wichers, Marieke; Lieverse, Ritsaert; van Os, Jim; van Amelsvoort, Therese; Schruers, Koen

2017-11-01

Fear generalization is a prominent feature of anxiety disorders and post-traumatic stress disorder (PTSD). It is defined as enhanced fear responding to a stimulus that bears similarities, but is not identical to a threatening stimulus. Pattern separation, a hippocampal-dependent process, is critical for stimulus discrimination; it transforms similar experiences or events into non-overlapping representations. This study is the first in humans to investigate the extent to which fear generalization relies on behavioral pattern separation abilities. Participants (N = 46) completed a behavioral task taxing pattern separation, and a neuroimaging fear conditioning and generalization paradigm. Results show an association between lower behavioral pattern separation performance and increased generalization in shock expectancy scores, but not in fear ratings. Furthermore, lower behavioral pattern separation was associated with diminished recruitment of the subcallosal cortex during presentation of generalization stimuli. This region showed functional connectivity with the orbitofrontal cortex and ventromedial prefrontal cortex. Together, the data provide novel experimental evidence that pattern separation is related to generalization of threat expectancies, and reduced fear inhibition processes in frontal regions. Deficient pattern separation may be critical in overgeneralization and therefore may contribute to the pathophysiology of anxiety disorders and PTSD. © The Author (2017). Published by Oxford University Press.

Separation of parent homopolymers from diblock copolymers by liquid chromatography under limiting conditions of desorption 4. Role of eluent and temperature.

Science.gov (United States)

Berek, Dušan

2010-11-01

Liquid chromatography under limiting conditions of desorption (LC LCD) enables fast, base-line discrimination of both parent homopolymers from various diblock copolymers in one single step. The low molecular admixtures are fully separated, as well. General rules are discussed in detail for selection of mobile phases and temperature applied in LC LCD of block copolymers. Typical practical separation examples are presented. It is shown that both the composition of the well-selected LC LCD mobile phase and the temperature of experiment may vary in a broad range without affecting the basics of method. This implies that the method is robust and user friendly.

An analytical model of the mechanical properties of bulk coal under confined stress

Science.gov (United States)

Wang, G.X.; Wang, Z.T.; Rudolph, V.; Massarotto, P.; Finley, R.J.

2007-01-01

This paper presents the development of an analytical model which can be used to relate the structural parameters of coal to its mechanical properties such as elastic modulus and Poisson's ratio under a confined stress condition. This model is developed primarily to support process modeling of coalbed methane (CBM) or CO2-enhanced CBM (ECBM) recovery from coal seam. It applied an innovative approach by which stresses acting on and strains occurring in coal are successively combined in rectangular coordinates, leading to the aggregated mechanical constants. These mechanical properties represent important information for improving CBM/ECBM simulations and incorporating within these considerations of directional permeability. The model, consisting of constitutive equations which implement a mechanically consistent stress-strains correlation, can be used as a generalized tool to study the mechanical and fluid behaviors of coal composites. An example using the model to predict the stress-strain correlation of coal under triaxial confined stress by accounting for the elastic and brittle (non-elastic) deformations is discussed. The result shows a good agreement between the prediction and the experimental measurement. ?? 2007 Elsevier Ltd. All rights reserved.

Fatigue response of a PZT multilayer actuator under high-field electric cycling with mechanical preload

Science.gov (United States)

Wang, Hong; Wereszczak, Andrew A.; Lin, Hua-Tay

2009-01-01

An electric fatigue test system was developed for evaluating the reliability of piezoelectric actuators with a mechanical loading capability. Fatigue responses of a lead zirconate titanate (PZT) multilayer actuator with a platethrough electrode configuration were studied under an electric field (1.7 times that of the coercive field of PZT material) and a concurrent mechanical preload (30.0 MPa). A total of 109 cycles was carried out. Variations in charge density and mechanical strain under the high electric field and constant mechanical loads were observed during the fatigue test. The dc and the first harmonic (at 10 Hz) dielectric and piezoelectric coefficients were subsequently characterized using fast Fourier transformation. Both the dielectric and the piezoelectric coefficients exhibited a monotonic decrease prior to 2.86×108 cycles under certain preloading conditions, and then fluctuated. Both the dielectric loss tangent and the piezoelectric loss tangent also fluctuated after a decrease. The results are interpreted and discussed with respect to domain wall activities, microdefects, and other anomalies.

Flow-induced separation in wall turbulence.

Science.gov (United States)

Nguyen, Quoc; Srinivasan, Chiranth; Papavassiliou, Dimitrios V

2015-03-01

One of the defining characteristics of turbulence is its ability to promote mixing. We present here a case where the opposite happens-simulation results indicate that particles can separate near the wall of a turbulent channel flow, when they have sufficiently different Schmidt numbers without use of any other means. The physical mechanism of the separation is understood when the interplay between convection and diffusion, as expressed by their characteristic time scales, is considered, leading to the determination of the necessary conditions for a successful separation between particles. Practical applications of these results can be found when very small particles need to be separated or removed from a fluid.

An investigation of the mechanism underlying teacher aggression : Testing I3 theory and the General Aggression Model

NARCIS (Netherlands)

Montuoro, Paul; Mainhard, Tim

2017-01-01

Background: Considerable research has investigated the deleterious effects of teachers responding aggressively to students who misbehave, but the mechanism underlying this dysfunctional behaviour remains unknown. Aims: This study investigated whether the mechanism underlying teacher aggression

Mechanical deployment system on aries an autonomous mobile robot

International Nuclear Information System (INIS)

Rocheleau, D.N.

1995-01-01

ARIES (Autonomous Robotic Inspection Experimental System) is under development for the Department of Energy (DOE) to survey and inspect drums containing low-level radioactive waste stored in warehouses at DOE facilities. This paper focuses on the mechanical deployment system-referred to as the camera positioning system (CPS)-used in the project. The CPS is used for positioning four identical but separate camera packages consisting of vision cameras and other required sensors such as bar-code readers and light stripe projectors. The CPS is attached to the top of a mobile robot and consists of two mechanisms. The first is a lift mechanism composed of 5 interlocking rail-elements which starts from a retracted position and extends upward to simultaneously position 3 separate camera packages to inspect the top three drums of a column of four drums. The second is a parallelogram special case Grashof four-bar mechanism which is used for positioning a camera package on drums on the floor. Both mechanisms are the subject of this paper, where the lift mechanism is discussed in detail

Feature-based attentional modulation increases with stimulus separation in divided-attention tasks.

Science.gov (United States)

Sally, Sharon L; Vidnyánsky, Zoltán; Papathomas, Thomas V

2009-01-01

Attention modifies our visual experience by selecting certain aspects of a scene for further processing. It is therefore important to understand factors that govern the deployment of selective attention over the visual field. Both location and feature-specific mechanisms of attention have been identified and their modulatory effects can interact at a neural level (Treue and Martinez-Trujillo, 1999). The effects of spatial parameters on feature-based attentional modulation were examined for the feature dimensions of orientation, motion and color using three divided-attention tasks. Subjects performed concurrent discriminations of two briefly presented targets (Gabor patches) to the left and right of a central fixation point at eccentricities of +/-2.5 degrees , 5 degrees , 10 degrees and 15 degrees in the horizontal plane. Gabors were size-scaled to maintain consistent single-task performance across eccentricities. For all feature dimensions, the data show a linear increase in the attentional effects with target separation. In a control experiment, Gabors were presented on an isoeccentric viewing arc at 10 degrees and 15 degrees at the closest spatial separation (+/-2.5 degrees ) of the main experiment. Under these conditions, the effects of feature-based attentional effects were largely eliminated. Our results are consistent with the hypothesis that feature-based attention prioritizes the processing of attended features. Feature-based attentional mechanisms may have helped direct the attentional focus to the appropriate target locations at greater separations, whereas similar assistance may not have been necessary at closer target spacings. The results of the present study specify conditions under which dual-task performance benefits from sharing similar target features and may therefore help elucidate the processes by which feature-based attention operates.

Visuospatial Orientational Shifts: Evidence for Three Independent Mechanisms.

Science.gov (United States)

Noonan, Michael; Axelrod, Seymour

While it is often assumed that a single mechanism underlies varied experimental evidences of selectivity, Berlyne (1969) suggested that attention-like selectivity may take place in a number of quite separate neural systems. This study examined the issue of visuospatial attention by investigating covert orientation or "looking out of the corner of…

Reliability Issues and Solutions in Flexible Electronics Under Mechanical Fatigue

Science.gov (United States)

Yi, Seol-Min; Choi, In-Suk; Kim, Byoung-Joon; Joo, Young-Chang

2018-03-01

Flexible devices are of significant interest due to their potential expansion of the application of smart devices into various fields, such as energy harvesting, biological applications and consumer electronics. Due to the mechanically dynamic operations of flexible electronics, their mechanical reliability must be thoroughly investigated to understand their failure mechanisms and lifetimes. Reliability issue caused by bending fatigue, one of the typical operational limitations of flexible electronics, has been studied using various test methodologies; however, electromechanical evaluations which are essential to assess the reliability of electronic devices for flexible applications had not been investigated because the testing method was not established. By employing the in situ bending fatigue test, we has studied the failure mechanism for various conditions and parameters, such as bending strain, fatigue area, film thickness, and lateral dimensions. Moreover, various methods for improving the bending reliability have been developed based on the failure mechanism. Nanostructures such as holes, pores, wires and composites of nanoparticles and nanotubes have been suggested for better reliability. Flexible devices were also investigated to find the potential failures initiated by complex structures under bending fatigue strain. In this review, the recent advances in test methodology, mechanism studies, and practical applications are introduced. Additionally, perspectives including the future advance to stretchable electronics are discussed based on the current achievements in research.

Adsorption mechanism of magnetically separable Fe{sub 3}O{sub 4}/graphene oxide hybrids

Energy Technology Data Exchange (ETDEWEB)

Ouyang, Ke [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Zhu, Chuanhe [Department of Civil, Construction and Environmental Engineering, Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States); Zhao, Ya; Wang, Leichao [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Xie, Shan, E-mail: wyuchemxs@126.com [Department of Chemical and Environment Engineering, Wuyi University, Jiangmen, Guangdong 529020 (China); Wang, Qun, E-mail: qunwang@iastate.edu [Department of Civil, Construction and Environmental Engineering, Department of Chemical and Biological Engineering, Iowa State University, Ames, IA 50011 (United States)

2015-11-15

Graphical abstract: A recyclable Fe{sub 3}O{sub 4}/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polylol approach and exhibited an effective adsorption of BPA in aqueous solution. - Highlights: • Magnetically separable Fe{sub 3}O{sub 4}/GO hybrids were synthesized via a facile one-pot polylol approach. • The Fe{sub 3}O{sub 4}/GO hybrid could be easily recovered and met the need of magnetic separation, exhibiting excellent reproducibility and reusability. • The hybrids showed excellent adsorption ability for bisphenol A in aqueous solution. • The effect of pH value, temperature and coexisting ions on the adsorption was studied. • π–π interactions were postulated to be the primary mechanisms of adsorption of BPA on Fe{sub 3}O{sub 4}/GO hybrids. - Abstract: A reclaimable Fe{sub 3}O{sub 4}/graphene oxide (GO) magnetic hybrid was successfully synthesized via a facile one-pot polyol approach and employed as a recyclable adsorbent for Bisphenol A (BPA) in aqueous solutions. The maximum adsorption capacity (q{sub m}) of the Fe{sub 3}O{sub 4}/GO hybrid for BPA was 72.80 mg/g at 273 K. The kinetics of the adsorption process and the adsorption isotherm data were fitted using the Freundlich equation and a pseudo-second-order kinetic model. The results of the thermodynamic parameters ΔH°, ΔS° and ΔG° showed that the adsorption process was exothermic and spontaneous. Furthermore, the reusability of the samples was investigated, and the results indicated that the samples exhibited high stability. The magnetic characterization demonstrated that hybrids were superparamagnetic and could be recovered conveniently by magnetic separation. The strong π–π interaction was determined to be the predominant driving force behind the adsorption of BPA onto the Fe{sub 3}O{sub 4}/GO hybrid. Therefore, the Fe{sub 3}O{sub 4}/GO hybrid could be regarded as a potential adsorbent for wastewater treatment and purification processes.

Biochemical mechanisms of signaling: perspectives in plants under arsenic stress.

Science.gov (United States)

Islam, Ejazul; Khan, Muhammad Tahir; Irem, Samra

2015-04-01

Plants are the ultimate food source for humans, either directly or indirectly. Being sessile in nature, they are exposed to various biotic and abiotic stresses because of changing climate that adversely effects their growth and development. Contamination of heavy metals is one of the major abiotic stresses because of anthropogenic as well as natural factors which lead to increased toxicity and accumulation in plants. Arsenic is a naturally occurring metalloid toxin present in the earth crust. Due to its presence in terrestrial and aquatic environments, it effects the growth of plants. Plants can tolerate arsenic using several mechanisms like phytochelation, vacuole sequestration and activation of antioxidant defense systems. Several signaling mechanisms have evolved in plants that involve the use of proteins, calcium ions, hormones, reactive oxygen species and nitric oxide as signaling molecules to cope with arsenic toxicity. These mechanisms facilitate plants to survive under metal stress by activating their defense systems. The pathways by which these stress signals are perceived and responded is an unexplored area of research and there are lots of gaps still to be filled. A good understanding of these signaling pathways can help in raising the plants which can perform better in arsenic contaminated soil and water. In order to increase the survival of plants in contaminated areas there is a strong need to identify suitable gene targets that can be modified according to needs of the stakeholders using various biotechnological techniques. This review focuses on the signaling mechanisms of plants grown under arsenic stress and will give an insight of the different sensory systems in plants. Furthermore, it provides the knowledge about several pathways that can be exploited to develop plant cultivars which are resistant to arsenic stress or can reduce its uptake to minimize the risk of arsenic toxicity through food chain thus ensuring food security. Copyright © 2015

Dynamic Response and Failure Mechanism of Brittle Rocks Under Combined Compression-Shear Loading Experiments

Science.gov (United States)

Xu, Yuan; Dai, Feng

2018-03-01

A novel method is developed for characterizing the mechanical response and failure mechanism of brittle rocks under dynamic compression-shear loading: an inclined cylinder specimen using a modified split Hopkinson pressure bar (SHPB) system. With the specimen axis inclining to the loading direction of SHPB, a shear component can be introduced into the specimen. Both static and dynamic experiments are conducted on sandstone specimens. Given carefully pulse shaping, the dynamic equilibrium of the inclined specimens can be satisfied, and thus the quasi-static data reduction is employed. The normal and shear stress-strain relationships of specimens are subsequently established. The progressive failure process of the specimen illustrated via high-speed photographs manifests a mixed failure mode accommodating both the shear-dominated failure and the localized tensile damage. The elastic and shear moduli exhibit certain loading-path dependence under quasi-static loading but loading-path insensitivity under high loading rates. Loading rate dependence is evidently demonstrated through the failure characteristics involving fragmentation, compression and shear strength and failure surfaces based on Drucker-Prager criterion. Our proposed method is convenient and reliable to study the dynamic response and failure mechanism of rocks under combined compression-shear loading.

Design options for cooperation mechanisms under the new European renewable energy directive

International Nuclear Information System (INIS)

Klessmann, Corinna; Lamers, Patrick; Ragwitz, Mario; Resch, Gustav

2010-01-01

In June 2009, a new EU directive on the promotion of renewable energy sources (RES) entered into effect. The directive 2009/28/EC, provides for three cooperation mechanisms that will allow member states to achieve their national RES target in cooperation with other member states: statistical transfer, joint projects, and joint support schemes. This article analyses the pros and cons of the three mechanisms and explores design options for their implementation through strategic and economic questions: How to counterbalance the major drawbacks of each mechanism? How to reflect a balance of costs and benefits between the involved member states? The analysis identifies a number of design options that respond to these questions, e.g. long term contracts to ensure sufficient flexibility for statistical transfers, a coordinated, standardised joint project approach to increase transparency in the European market, and a stepwise harmonisation of joint support schemes that is based on a cost-effective accounting approach. One conclusion is that the three cooperation mechanisms are closely interlinked. One can consider their relation to be a gradual transition from member state cooperation under fully closed national support systems in case of statistical transfers, to cooperation under fully open national support systems in a joint support scheme.

Using neuronal populations to study the mechanisms underlying spatial and feature attention

Science.gov (United States)

Cohen, Marlene R.; Maunsell, John H.R.

2012-01-01

Summary Visual attention affects both perception and neuronal responses. Whether the same neuronal mechanisms mediate spatial attention, which improves perception of attended locations, and non-spatial forms of attention has been a subject of considerable debate. Spatial and feature attention have similar effects on individual neurons. Because visual cortex is retinotopically organized, however, spatial attention can co-modulate local neuronal populations, while feature attention generally requires more selective modulation. We compared the effects of feature and spatial attention on local and spatially separated populations by recording simultaneously from dozens of neurons in both hemispheres of V4. Feature and spatial attention affect the activity of local populations similarly, modulating both firing rates and correlations between pairs of nearby neurons. However, while spatial attention appears to act on local populations, feature attention is coordinated across hemispheres. Our results are consistent with a unified attentional mechanism that can modulate the responses of arbitrary subgroups of neurons. PMID:21689604

Mechanisms underlying the associations of maternal age with adverse perinatal outcomes

DEFF Research Database (Denmark)

Lawlor, Debbie A; Mortensen, Laust; Andersen, Anne-Marie Nybo

2011-01-01

The mechanisms underlying the association between maternal age (both young and older maternal age) and adverse perinatal outcomes are unclear. Methods We examined the association of maternal age at first birth with preterm birth (<37 weeks gestation) and small for gestational age (SGA) in a cohor...

An utilization of liquid sublayer dryout mechanism in predicting critical heat flux under low pressure and low velocity conditions in round tubes

International Nuclear Information System (INIS)

Lee, Kwang-Won; Baik, Se-Jin; Ro, Tae-Sun

2000-01-01

From a theoretical assessment of extensive critical heat flux (CHF) data under low pressure and low velocity (LPLV) conditions, it was found out that lots of CHF data would not be well predicted by a normal annular film dryout (AFD) mechanism, although their flow patterns were identified as annular-mist flow. To predict these CHF data, a liquid sublayer dryout (LSD) mechanism has been newly utilized in developing the mechanistic CHF model based on each identified CHF mechanism. This mechanism postulates that the CHF occurrence is caused by dryout of the thin liquid sublayer resulting from the annular film separation or breaking down due to nucleate boiling in annular film or hydrodynamic fluctuation. In principle, this mechanism well supports the experimental evidence of residual film flow rate at the CHF location, which can not be explained by the AFD mechanism. For a comparative assessment of each mechanism, the CHF model based on the LSD mechanism is developed together with that based on the AFD mechanism. The validation of these models is performed on the 1406 CHF data points ranging over P=0.1-2 MPa, G=4-499 kg m -2 s -1 , L/D=4-402. This model validation shows that 1055 and 231 CHF data are predicted within ±30 error bound by the LSD mechanism and the AFD mechanism, respectively. However, some CHF data whose critical qualities are <0.4 or whose tube length-to-diameter ratios are <70 are considerably overestimated by the CHF model based on the LSD mechanism. These overestimations seem to be caused by an inadequate CHF mechanism classification and an insufficient consideration of the flow instability effect on CHF. Further studies for a new classification criterion screening the CHF data affected by flow instabilities as well as a new bubble detachment model for LPLV conditions, are needed to improve the model accuracy.

New understanding on separation of Mn and Fe from ferruginous manganese ores by the magnetic reduction roasting process

Science.gov (United States)

Liu, Bingbing; Zhang, Yuanbo; Wang, Juan; Wang, Jia; Su, Zijian; Li, Guanghui; Jiang, Tao

2018-06-01

Magnetic reduction roasting followed by magnetic separation process is reported as a simple route to realize separation of Mn and Fe from ferruginous manganese ores (Fe-Mn ores). However, the separation and recovery of Mn and Fe oxides are not very effective. This work clarified the underlying reason for the poor separation and also proposed some suggestions for the magnetic reduction process. In this work, the effect of temperature on the magnetic reduction roasting - magnetic separation of Fe-Mn ore was investigated firstly. Then the reduction behaviors of MnO2-Fe2O3 system and MnO2-Fe2O3-10 wt.%SiO2 system under 10 vol.% CO-90 vol.% CO2 at 600-1000 °C were investigated by XRD, XPS, SEM-EDS, VSM, DSC and thermodynamics analyses. Reduction and separation tests showed that higher reduction temperature was beneficial to the recovery of iron while it's not in favor of the recovery of manganese when the temperature was over 800 °C. The formation of composite oxide MnxFe3-xO4 with strong magnetism between the interface of the MnO2 and Fe2O3 particles leaded to the poor separation of iron and manganese. In addition, the formation mechanism of MnxFe3-xO4 from MnO2 and Fe2O3 as well as the interface reaction reduced under 10 vol.% CO was discussed in this study. Finally, some suggestions were recommended for the magnetic reduction roasting for utilizing the Fe-Mn ores effectively.

Investigation of sheet steel St 37.2 under mechanical impact

International Nuclear Information System (INIS)

Berg, H.P.; Brennecke, P.; Koester, R.; Friehmelt, V.

1990-01-01

Special waste originating, e.g. from chemical industry and radioactive wastes are emplaced in disposal mines. Slinger stowing is an approved technique to fill up residual voids in emplacement rooms. If it should be applied, possible mechanical loads on the integrity of sheet steel containers have to be considered. By theoretical calculations and by experiments under variation of different parameters using test specimen and backfill material from the Konrad mine using the container type V as an example it has been shown that sheet steel St 37.2 with a wall thickness of 3 mm will withstand mechanical impact imposed by backfill particles having a speed of 24 m/s. (orig.) [de

Hydrogen separation process

Science.gov (United States)

Mundschau, Michael [Longmont, CO; Xie, Xiaobing [Foster City, CA; Evenson, IV, Carl; Grimmer, Paul [Longmont, CO; Wright, Harold [Longmont, CO

2011-05-24

A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to a hydrogen separation membrane system comprising a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for separating a hydrogen-rich product stream from a feed stream comprising hydrogen and at least one carbon-containing gas, comprising feeding the feed stream, at an inlet pressure greater than atmospheric pressure and a temperature greater than 200.degree. C., to an integrated water gas shift/hydrogen separation membrane system wherein the hydrogen separation membrane system comprises a membrane that is selectively permeable to hydrogen, and producing a hydrogen-rich permeate product stream on the permeate side of the membrane and a carbon dioxide-rich product raffinate stream on the raffinate side of the membrane. A method for pretreating a membrane, comprising: heating the membrane to a desired operating temperature and desired feed pressure in a flow of inert gas for a sufficient time to cause the membrane to mechanically deform; decreasing the feed pressure to approximately ambient pressure; and optionally, flowing an oxidizing agent across the membrane before, during, or after deformation of the membrane. A method of supporting a hydrogen separation membrane system comprising selecting a hydrogen separation membrane system comprising one or more catalyst outer layers deposited on a hydrogen transport membrane layer and sealing the hydrogen separation membrane system to a porous support.

Investigation on the interaction of catalase with sodium lauryl sulfonate and the underlying mechanisms.

Science.gov (United States)

Wang, Jing; Jia, Rui; Wang, Jiaxi; Sun, Zhiqiang; Wu, Zitao; Liu, Rutao; Zong, Wansong

2018-02-01

As a classic type of anionic surfactants, sodium lauryl sulfonate (SLS) might change the structure and function of antioxidant enzyme catalase (CAT) through their direct interactions. However, the underlying molecular mechanism is still unknown. This study investigated the direct interaction of SLS with CAT molecule and the underlying mechanisms using multi-spectroscopic methods, isothermal titration calorimetry, and molecular docking studies. No obvious effects were observed on CAT structure and activity under low SLS concentration exposure. The particle size of CAT molecule decreased and CAT activity was slightly inhibited under high SLS concentration exposure. SLS prefers to bind to the interface of CAT mainly via van der Waals' forces and hydrogen bonds. Subsequently, SLS interacts with the amino acid residues around the heme groups of CAT via hydrophobic interactions and might inhibit CAT activity. © 2017 Wiley Periodicals, Inc.

Gas separation techniques in nuclear facilities

International Nuclear Information System (INIS)

Hioki, Hideaki; Morisue, Tetsuo; Ohno, Masayoshi

1983-01-01

The literatures concerning the gas separation techniques which are applied to the waste gases generated from nuclear power plants and nuclear fuel reprocessing plants, uranium enrichment and the instrumentation of nuclear facilities are reviewed. The gas permeability and gas separation performance of membranes are discussed in terms of rare gas separation. The investigation into the change of the gas permeability and mechanical properties of membranes with exposure to radiation is reported. The theoretical investigation of the separating cells used for the separation of rare gas and the development of various separating cells are described, and the theoretical and experimental investigations concerning rare gas separation using cascades are described. The application of membrane method to nuclear facilities is explained showing the examples of uranium enrichment, the treatment of waste gases from nuclear reactor buildings and nuclear fuel reprocessing plants, the monitoring of low level β-emitters in stacks, the detection of failed fuels and the detection of water leak in fast breeder reactors. (Yoshitake, I.)

Vortex Formation During Unsteady Boundary-Layer Separation

Science.gov (United States)

Das, Debopam; Arakeri, Jaywant H.

1998-11-01

Unsteady laminar boundary-layer separation is invariably accompanied by the formation of vortices. The aim of the present work is to study the vortex formation mechanism(s). An adverse pressure gradient causing a separation can be decomposed into a spatial component ( spatial variation of the velocity external to the boundary layer ) and a temporal component ( temporal variation of the external velocity ). Experiments were conducted in a piston driven 2-D water channel, where the spatial component could be be contolled by geometry and the temporal component by the piston motion. We present results for three divergent channel geometries. The piston motion consists of three phases: constant acceleration from start, contant velocity, and constant deceleration to stop. Depending on the geometry and piston motion we observe different types of unsteady separation and vortex formation.

A new submarine oil-water separation system

Science.gov (United States)

Cai, Wen-Bin; Liu, Bo-Hong

2017-12-01

In order to solve the oil field losses of environmental problems and economic benefit caused by the separation of lifting production liquid to offshore platforms in the current offshore oil production, from the most basic separation principle, a new oil-water separation system has been processed of adsorption and desorption on related materials, achieving high efficiency and separation of oil and water phases. And the submarine oil-water separation device has been designed. The main structure of the device consists of gas-solid phase separation device, period separating device and adsorption device that completed high efficiency separation of oil, gas and water under the adsorption and desorption principle, and the processing capacity of the device is calculated.

Detecting method for crude oil price fluctuation mechanism under different periodic time series

International Nuclear Information System (INIS)

Gao, Xiangyun; Fang, Wei; An, Feng; Wang, Yue

2017-01-01

Highlights: • We proposed the concept of autoregressive modes to indicate the fluctuation patterns. • We constructed transmission networks for studying the fluctuation mechanism. • There are different fluctuation mechanism under different periodic time series. • Only a few types of autoregressive modes control the fluctuations in crude oil price. • There are cluster effects during the fluctuation mechanism of autoregressive modes. - Abstract: Current existing literatures can characterize the long-term fluctuation of crude oil price time series, however, it is difficult to detect the fluctuation mechanism specifically under short term. Because each fluctuation pattern for one short period contained in a long-term crude oil price time series have dynamic characteristics of diversity; in other words, there exhibit various fluctuation patterns in different short periods and transmit to each other, which reflects the reputedly complicate and chaotic oil market. Thus, we proposed an incorporated method to detect the fluctuation mechanism, which is the evolution of the different fluctuation patterns over time from the complex network perspective. We divided crude oil price time series into segments using sliding time windows, and defined autoregressive modes based on regression models to indicate the fluctuation patterns of each segment. Hence, the transmissions between different types of autoregressive modes over time form a transmission network that contains rich dynamic information. We then capture transmission characteristics of autoregressive modes under different periodic time series through the structure features of the transmission networks. The results indicate that there are various autoregressive modes with significantly different statistical characteristics under different periodic time series. However, only a few types of autoregressive modes and transmission patterns play a major role in the fluctuation mechanism of the crude oil price, and these

Amalgam-chromatographic separation of magnesium isotopes

International Nuclear Information System (INIS)

Klinskij, G.D.; Levkin, A.V.; Ivanov, S.A.

1990-01-01

Separation of magnesium isotopes within Mg(Hg)-MgI 2 system (in dimethylformamide) is conducted under amalgam-chromatographic conditions. Separation maximal degree, that is (1.09), for 24 Mg and 26 Mg and separation coefficient (α = 1.0089±0.006) are determined. Light isotopes are found to concentrate in the amalgam. Technique of thermal conversion of flows within amalgam-dimethylformamide system is suggested on the basis of reversible reaction of Ca-Mg element exchange

Particle acceleration at a reconnecting magnetic separator

Science.gov (United States)

Threlfall, J.; Neukirch, T.; Parnell, C. E.; Eradat Oskoui, S.

2015-02-01

Context. While the exact acceleration mechanism of energetic particles during solar flares is (as yet) unknown, magnetic reconnection plays a key role both in the release of stored magnetic energy of the solar corona and the magnetic restructuring during a flare. Recent work has shown that special field lines, called separators, are common sites of reconnection in 3D numerical experiments. To date, 3D separator reconnection sites have received little attention as particle accelerators. Aims: We investigate the effectiveness of separator reconnection as a particle acceleration mechanism for electrons and protons. Methods: We study the particle acceleration using a relativistic guiding-centre particle code in a time-dependent kinematic model of magnetic reconnection at a separator. Results: The effect upon particle behaviour of initial position, pitch angle, and initial kinetic energy are examined in detail, both for specific (single) particle examples and for large distributions of initial conditions. The separator reconnection model contains several free parameters, and we study the effect of changing these parameters upon particle acceleration, in particular in view of the final particle energy ranges that agree with observed energy spectra.

Mechanical properties of the human spinal cord under the compressive loading.

Science.gov (United States)

Karimi, Alireza; Shojaei, Ahmad; Tehrani, Pedram

2017-12-01

The spinal cord as the most complex and critical part of the human body is responsible for the transmission of both motor and sensory impulses between the body and the brain. Due to its pivotal role any types of physical injury in that disrupts its function following by shortfalls, including the minor motor and sensory malfunctions as well as complicate quadriplegia and lifelong ventilator dependency. In order to shed light on the injuries to the spinal cord, the application of the computational models to simulate the trauma impact loading to that are deemed required. Nonetheless, it has not been fulfilled since there is a paucity of knowledge about the mechanical properties of the spinal cord, especially the cervical one, under the compressive loading on the grounds of the difficulty in obtaining this tissue from the human body. This study was aimed at experimentally measuring the mechanical properties of the human cervical spinal cord of 24 isolated fresh samples under the unconfined compressive loading at a relatively low strain rate. The stress-strain data revealed the elastic modulus and maximum/failure stress of 40.12±6.90 and 62.26±5.02kPa, respectively. Owing to the nonlinear response of the spinal cord, the Yeoh, Ogden, and Mooney-Rivlin hyperelastic material models have also been employed. The results may have implications not only for understanding the linear elastic and nonlinear hyperelastic mechanical properties of the cervical spinal cord under the compressive loading, but also for providing a raw data for investigating the injury as a result of the trauma thru the numerical simulations. Copyright © 2017 Elsevier B.V. All rights reserved.

Reliability-based optimization of maintenance scheduling of mechanical components under fatigue

Science.gov (United States)

Beaurepaire, P.; Valdebenito, M.A.; Schuëller, G.I.; Jensen, H.A.

2012-01-01

This study presents the optimization of the maintenance scheduling of mechanical components under fatigue loading. The cracks of damaged structures may be detected during non-destructive inspection and subsequently repaired. Fatigue crack initiation and growth show inherent variability, and as well the outcome of inspection activities. The problem is addressed under the framework of reliability based optimization. The initiation and propagation of fatigue cracks are efficiently modeled using cohesive zone elements. The applicability of the method is demonstrated by a numerical example, which involves a plate with two holes subject to alternating stress. PMID:23564979

Theoretical investigation of gas separation in functionalized nanoporous graphene membranes

Science.gov (United States)

Wang, Yong; Yang, Qingyuan; Zhong, Chongli; Li, Jinping

2017-06-01

Graphene has enormous potential as a membrane-separation material with ultrahigh permeability and selectivity. The understanding of mass-transport mechanism in graphene membranes is crucial for applications in gas separation field. We computationally investigated the capability and mechanisms of functionalized nanoporous graphene membranes for gas separation. The functionalized graphene membranes with appropriate pore size and geometry possess excellent high selectivity for separating CO2/N2, CO2/CH4 and N2/CH4 gas mixtures with a gas permeance of ∼103-105 GPU, compared with ∼100 GPU for typical polymeric membranes. More important, we found that, for ultrathin graphene membranes, the gas separation performance has a great dependence not only with the energy barrier for gas getting into the pore of the graphene membranes, but also with the energy barrier for gas escaping from the pore to the other side of the membranes. The gas separation performance can be tuned by changing the two energy barriers, which can be realized by varying the chemical functional groups on the pore rim of the graphene. The novel mass-transport mechanism obtained in current study may provide a theoretical foundation for guiding the future design of graphene membranes with outstanding separation performance.

Behavior of duplex stainless steel casting defects under mechanical loadings

International Nuclear Information System (INIS)

Jayet-Gendrot, S.; Gilles, P.

2000-01-01

Several components in the primary circuit of pressurized water reactors are made of cast duplex stainless steels. This material contains small casting defects, mainly shrinkage cavities, due to the manufacturing process. In safety analyses, the structural integrity of the components is studied under the most severe assumptions: presence of a large defect, accidental loadings and end-of-life material properties accounting for its thermal aging embrittlement at the service temperature. The casting defects are idealized as semi-circular surface cracks or notches that have envelope dimensions. In order to assess the real severity of the casting defects under mechanical loadings, an experimental program was carried out. It consisted of testing, under both cyclic and monotonic solicitations, three-point bend specimens containing either a natural defect (in the form of a localized cluster of cavities) or a machined notch having the dimensions of the cluster's envelope. The results show that shrinkage cavities are far less harmful than envelope notches thanks to the metal bridges between cavities. Under fatigue loadings, the generalized initiation of a cluster of cavities (defined when the cluster becomes a crack of the same global size) is reached for a number of cycles that is much higher than the one leading to the initiation of a notch. In the case of monotonic loadings, specimens with casting defects offer a very high resistance to ductile tearing. The tests are analyzed in order to develop a method that takes into account the behavior of casting defects in a more realistic fashion than by an envelope crack. Various approaches are investigated, including the search of equivalent defects or of criteria based on continuum mechanics concepts, and compared with literature data. This study shows the conservatism of current safety analyses in modeling casting defects by envelope semi-elliptical cracks and contributes to the development of alternative approaches. (orig.)

Contact force and mechanical loss of multistage cable under tension and bending

Science.gov (United States)

Ru, Yanyun; Yong, Huadong; Zhou, Youhe

2016-10-01

A theoretical model for calculating the stress and strain states of cabling structures with different loadings has been developed in this paper. We solve the problem for the first- and second-stage cable with tensile or bending strain. The contact and friction forces between the strands are presented by two-dimensional contact model. Several theoretical models have been proposed to verify the results when the triplet subjected to the tensile strain, including contact force, contact stresses, and mechanical loss. It is found that loadings will affect the friction force and the mechanical loss of the triplet. The results show that the contact force and mechanical loss are dependent on the twist pitch. A shorter twist pitch can lead to higher contact force, while the trend of mechanical loss with twist pitch is complicated. The mechanical loss may be reduced by adjusting the twist pitch reasonably. The present model provides a simple analysis method to investigate the mechanical behaviors in multistage-structures under different loads.

Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions

Science.gov (United States)

2013-01-01

REPORT Friction Stir Weld Failure Mechanisms in Aluminum-Armor Structures Under Ballistic Impact Loading Conditions 14. ABSTRACT 16. SECURITY...properties and of the attendant ballistic-impact failure mechanisms in prototypical friction stir welding (FSW) joints found in armor structures made of high...mechanisms, friction stir welding M. Grujicic, B. Pandurangan, A. Arakere, C-F. Yen, B. A. Cheeseman Clemson University Office of Sponsored Programs 300

Embryonic left-right separation mechanism allows confinement of mutation-induced phenotypes to one lateral body half of bilaterians.

Science.gov (United States)

Ma, Kun

2013-12-01

A fundamental question in developmental biology is how a chimeric animal such as a bilateral gynandromorphic animal can have different phenotypes confined to different lateral body halves, and how mutation-induced phenotypes, such as genetic diseases, can be confined to one lateral body half in patients. Here, I propose that embryos of many, if not all, bilaterian animals are divided into left and right halves at a very early stage (which may vary among different types of animals), after which the descendants of the left-sided and right-sided cells will almost exclusively remain on their original sides, respectively, throughout the remaining development. This embryonic left-right separation mechanism allows (1) mutations and the mutation-induced phenotypes to be strictly confined to one lateral body half in animals and humans; (2) mothers with bilateral hereditary primary breast cancer to transmit their disease to their offspring at twofold of the rate compared to mothers with unilateral hereditary breast cancer; and (3) a mosaic embryo carrying genetic or epigenetic mutations to develop into either an individual with the mutation-induced phenotype confined unilaterally, or a pair of twins displaying complete, partial, or mirror-image discordance for the phenotype. Further, this left-right separation mechanism predicts that the two lateral halves of a patient carrying a unilateral genetic disease can each serve as a case and an internal control, respectively, for genetic and epigenetic comparative studies to identify the disease causations. © 2013 Wiley Periodicals, Inc.

Organic-inorganic hybrid membranes in separation processes: a 10-year review

Directory of Open Access Journals (Sweden)

V. C. Souza

2013-12-01

Full Text Available In relation to some inorganic membranes, polymeric membranes have relatively low separation performance. However, the processing flexibility and low cost of polymers still make them highly attractive for many industrial separation applications. Polymer-inorganic hybrid membranes constitute an emerging research field and have been recently developed to improve the separation properties of polymer membranes because they possess properties of both organic and inorganic membranes such as good hydrophilicity, selectivity, permeability, mechanical strength, and thermal and chemical stability. The structures and processing of polymer-inorganic nanocomposite hybrid membranes, as well as their use in the fields of ultrafiltration, nanofiltration, pervaporation, gas separation and separation mechanism are reviewed.

Gas/vapour separation using ultra-microporous metal–organic frameworks: insights into the structure/separation relationship

KAUST Repository

Adil, Karim; Belmabkhout, Youssef; Pillai, Renjith S.; Cadiau, Amandine; Bhatt, Prashant; Assen, Ayalew Hussen Assen; Maurin, Guillaume; Eddaoudi, Mohamed

2017-01-01

The separation of related molecules with similar physical/chemical properties is of prime industrial importance and practically entails a substantial energy penalty, typically necessitating the operation of energy-demanding low temperature fractional distillation techniques. Certainly research efforts, in academia and industry alike, are ongoing with the main aim to develop advanced functional porous materials to be adopted as adsorbents for the effective and energy-efficient separation of various important commodities. Of special interest is the subclass of metal-organic frameworks (MOFs) with pore aperture sizes below 5-7 Å, namely ultra-microporous MOFs, which in contrast to conventional zeolites and activated carbons show great prospects for addressing key challenges in separations pertaining to energy and environmental sustainability, specifically materials for carbon capture and separation of olefin/paraffin, acetylene/ethylene, linear/branched alkanes, xenon/krypton, etc. In this tutorial review we discuss the latest developments in ultra-microporous MOF adsorbents and their use as separating agents via thermodynamics and/or kinetics and molecular sieving. Appreciably, we provide insights into the distinct microscopic mechanisms governing the resultant separation performances, and suggest a plausible correlation between the inherent structural features/topology of MOFs and the associated gas/vapour separation performance.

Gas/vapour separation using ultra-microporous metal–organic frameworks: insights into the structure/separation relationship

KAUST Repository

Adil, Karim

2017-05-30

The separation of related molecules with similar physical/chemical properties is of prime industrial importance and practically entails a substantial energy penalty, typically necessitating the operation of energy-demanding low temperature fractional distillation techniques. Certainly research efforts, in academia and industry alike, are ongoing with the main aim to develop advanced functional porous materials to be adopted as adsorbents for the effective and energy-efficient separation of various important commodities. Of special interest is the subclass of metal-organic frameworks (MOFs) with pore aperture sizes below 5-7 Å, namely ultra-microporous MOFs, which in contrast to conventional zeolites and activated carbons show great prospects for addressing key challenges in separations pertaining to energy and environmental sustainability, specifically materials for carbon capture and separation of olefin/paraffin, acetylene/ethylene, linear/branched alkanes, xenon/krypton, etc. In this tutorial review we discuss the latest developments in ultra-microporous MOF adsorbents and their use as separating agents via thermodynamics and/or kinetics and molecular sieving. Appreciably, we provide insights into the distinct microscopic mechanisms governing the resultant separation performances, and suggest a plausible correlation between the inherent structural features/topology of MOFs and the associated gas/vapour separation performance.

Mechanisms underlying prorenin actions on hypothalamic neurons implicated in cardiometabolic control

Directory of Open Access Journals (Sweden)

Soledad Pitra

2016-10-01

Conclusions: We identified novel neuronal targets and cellular mechanisms underlying PR/PRR actions in critical hypothalamic neurons involved in cardiometabolic regulation. This fundamental mechanistic information regarding central PR/PRR actions is essential for the development of novel RAS-based therapeutic targets for the treatment of cardiometabolic disorders in obesity and hypertension.

Evaluation of fuel release rate and mechanism tests under RBCB conditions

International Nuclear Information System (INIS)

Adamson, M.G.

1981-09-01

This task includes theoretical evaluation of fuel/fission product release behavior from failed LMFBR fuel elements as well as an on-going experimental investigation of the mechanism of oxide fuel dispersal into flowing liquid sodium. The primary objectives of this work are to develop a fuel source term that can be used in predictive models for primary heat transfer system contamination and to understand the separate influences of important system variables (such as flow rate, oxygen impurity level) on this source term. The present report is written in two parts: the first, in condensed form, is an updated evaluation of fuel (U,Pu) and fission product release data, and the second describes the current status of supporting experimental work at General Electric's Vallecitos Laboratory

Separated Flow over Wind Turbines

Science.gov (United States)

Brown, David; Lewalle, Jacques

2015-11-01

The motion of the separation point on an airfoil under unsteady flow can affect its performance and longevity. Of interest is to understand and control the performance decrease in wind turbines subject to turbulent flow. We examine flow separation on an airfoil at a 19 degree angle of attack under unsteady flow conditions. We are using a DU-96-W180 airfoil of chord length 242 mm. The unsteadiness is generated by a cylinder with diameter 203 mm located 7 diameters upstream of the airfoil's leading edge. The data comes from twenty surface pressure sensors located on the top and bottom of the airfoil as well as on the upstream cylinder. Methods of analysis include Mexican hat transforms, Morlet wavelet transforms, power spectra, and various cross correlations. With this study I will explore how the differences of signals on the pressure and suction sides of an airfoil are related to the motion of the separation point.

Model test study of evaporation mechanism of sand under constant atmospheric condition

OpenAIRE

CUI, Yu Jun; DING, Wenqi; SONG, Weikang

2014-01-01

The evaporation mechanism of Fontainebleau sand using a large-scale model chamber is studied. First, the evaporation test on a layer of water above sand surface is performed under various atmospheric conditions, validating the performance of the chamber and the calculation method of actual evaporation rate by comparing the calculated and measured cumulative evaporations. Second,the evaporation test on sand without water layer is conducted under constant atmospheric condition. Both the evoluti...

Contraction and elongation: Mechanics underlying cell boundary deformations in epithelial tissue.

Science.gov (United States)

Hara, Yusuke

2017-06-01

The cell-cell boundaries of epithelial cells form cellular frameworks at the apical side of tissues. Deformations in these boundaries, for example, boundary contraction and elongation, and the associated forces form the mechanical basis of epithelial tissue morphogenesis. In this review, using data from recent Drosophila studies on cell boundary contraction and elongation, I provide an overview of the mechanism underlying the bi-directional deformations in the epithelial cell boundary, that are sustained by biased accumulations of junctional and apico-medial non-muscle myosin II. Moreover, how the junctional tensions exist on cell boundaries in different boundary dynamics and morphologies are discussed. Finally, some future perspectives on how recent knowledge about single cell boundary-level mechanics will contribute to our understanding of epithelial tissue morphogenesis are discussed. © 2017 Japanese Society of Developmental Biologists.

The Mediated MIMIC Model for Understanding the Underlying Mechanism of DIF

Science.gov (United States)

Cheng, Ying; Shao, Can; Lathrop, Quinn N.

2016-01-01

Due to its flexibility, the multiple-indicator, multiple-causes (MIMIC) model has become an increasingly popular method for the detection of differential item functioning (DIF). In this article, we propose the mediated MIMIC model method to uncover the underlying mechanism of DIF. This method extends the usual MIMIC model by including one variable…

Mechanical Behaviour of Bolted Joints Under Impact Rates of Loading

Science.gov (United States)

2012-01-01

M. (1995). Bearing Strength of Autoclave and oven cured kevlar / epoxy laminates under static and dynamic loading. Compostes, 451-456. Kretsis, G...Joints in Glass Fibre/ Epoxy Laminates. Composites, Volume 16. No 2. Kolsky, H. (1949). An Investigation of the Mechanical Properties of Materials at...elongating the pulse width. The responses are read by the strain gages bonded on the incident and transmission bar with Vishay AE-10 epoxy . The gages

Separations Science Data Base: an abstractor's manual

International Nuclear Information System (INIS)

Roddy, J.W.; McDowell, W.J.; Michelson, D.C.

1981-07-01

The Separations Science Data Base, designed specifically for the retrieval of information needed in chemical separations problems (i.e., how to perform a given separation under given conditions), is described. The procedure for entering records into the data base is given. The initial entries are concerned primarily with liquid-liquid extraction and liquid-solid ion exchange methods for metal ions and salts; however, the data base is constructed so that almost any separations process can be accommodated. Each record is indexed with information provided under the following fields: author; title; publication source; date of publication; organization performing and/or sponsoring the work; brief abstract of the work; abstract number if the work has been so referenced, and/or abstractor's initials; type of separation system used (e.g., flotation); specific or generic name of the separation agent used (e.g., acetylacetone); list of substances separated (e.g., gold, copper); qualitative description of the supporting medium or matrix containing the substances before separation (e.g., nitrate); type of literature where the article was printed (e.g., book); and type of information that the article contains. Each of these fields may be searched independently of the others (or in combination), and the last six fields contain specific key words that are listed on the input form. Definitions are provided for the 39 information terms

Effect of preoperative oral midazolam sedation on separation anxiety and emergence delirium among children undergoing dental treatment under general anesthesia

Science.gov (United States)

El Batawi, Hisham Yehia

2015-01-01

Aim: To investigate the possible effects of preoperative oral Midazolam on parental separation anxiety, emergence delirium, and post-anesthesia care unit time on children undergoing dental rehabilitation under general anesthesia. Methods: Randomized, prospective, double-blind study. Seventy-eight American Society of Anesthesiology (ASA) I children were divided into two groups of 39 each. Children of the first group were premedicated with oral Midazolam 0.5 mg/kg, while children of the control group were premedicated with a placebo. Scores for parental separation, mask acceptance, postoperative emergence delirium, and time spent in the post-anesthesia care unit were compared statistically. Results: The test group showed significantly lower parental separation scores and high acceptance rate for anesthetic mask. There was no significant difference between the two groups regarding emergence delirium and time spent in post-anesthesia care unit. Conclusions: Preoperative oral Midazolam could be a useful adjunct in anxiety management for children suffering dental anxiety. The drug may not reduce the incidence of postoperative emergence delirium. The suggested dose does not seem to affect the post-anesthesia care unit time. PMID:25992332

Effect of preoperative oral midazolam sedation on separation anxiety and emergence delirium among children undergoing dental treatment under general anesthesia.

Science.gov (United States)

El Batawi, Hisham Yehia

2015-01-01

To investigate the possible effects of preoperative oral Midazolam on parental separation anxiety, emergence delirium, and post-anesthesia care unit time on children undergoing dental rehabilitation under general anesthesia. Randomized, prospective, double-blind study. Seventy-eight American Society of Anesthesiology (ASA) I children were divided into two groups of 39 each. Children of the first group were premedicated with oral Midazolam 0.5 mg/kg, while children of the control group were premedicated with a placebo. Scores for parental separation, mask acceptance, postoperative emergence delirium, and time spent in the post-anesthesia care unit were compared statistically. The test group showed significantly lower parental separation scores and high acceptance rate for anesthetic mask. There was no significant difference between the two groups regarding emergence delirium and time spent in post-anesthesia care unit. Preoperative oral Midazolam could be a useful adjunct in anxiety management for children suffering dental anxiety. The drug may not reduce the incidence of postoperative emergence delirium. The suggested dose does not seem to affect the post-anesthesia care unit time.

Neural mechanisms underlying cognitive control of men with lifelong antisocial behavior.

Science.gov (United States)

Schiffer, Boris; Pawliczek, Christina; Mu Ller, Bernhard; Forsting, Michael; Gizewski, Elke; Leygraf, Norbert; Hodgins, Sheilagh

2014-04-30

Results of meta-analyses suggested subtle deficits in cognitive control among antisocial individuals. Because almost all studies focused on children with conduct problems or adult psychopaths, however, little is known about cognitive control mechanisms among the majority of persistent violent offenders who present an antisocial personality disorder (ASPD). The present study aimed to determine whether offenders with ASPD, relative to non-offenders, display dysfunction in the neural mechanisms underlying cognitive control and to assess the extent to which these dysfunctions are associated with psychopathic traits and trait impulsivity. Participants comprised 21 violent offenders and 23 non-offenders who underwent event-related functional magnetic resonance imaging while performing a non-verbal Stroop task. The offenders, relative to the non-offenders, exhibited reduced response time interference and a different pattern of conflict- and error-related activity in brain areas involved in cognitive control, attention, language, and emotion processing, that is, the anterior cingulate, dorsolateral prefrontal, superior temporal and postcentral cortices, putamen, thalamus, and amygdala. Moreover, between-group differences in behavioural and neural responses revealed associations with core features of psychopathy and attentional impulsivity. Thus, the results of the present study confirmed the hypothesis that offenders with ASPD display alterations in the neural mechanisms underlying cognitive control and that those alterations relate, at least in part, to personality characteristics. Copyright © 2014. Published by Elsevier Ireland Ltd.

Microbubble Distillation for Ethanol-Water Separation

Directory of Open Access Journals (Sweden)

Atheer Al-yaqoobi

2016-01-01

Full Text Available In the current study, a novel approach for separating ethanol-water mixture by microbubble distillation technology was investigated. Traditional distillation processes require large amounts of energy to raise the liquid to its boiling point to effect removal of volatile components. The concept of microbubble distillation by comparison is to heat the gas phase rather than the liquid phase to achieve separation. The removal of ethanol from the thermally sensitive fermentation broths was taken as a case of study. Consequently the results were then compared with those which could be obtained under equilibrium conditions expected in an “ideal” distillation unit. Microbubble distillation has achieved vapour compositions higher than that which could be obtained under traditional equilibrium conditions. The separation was achieved at liquid temperature significantly less than the boiling point of the mixture. In addition, it was observed that the separation efficiency of the microbubble distillation could be increased by raising the injected air temperature, while the temperature of the liquid mixture increased only moderately. The separation efficiency of microbubble distillation was compared with that of pervaporation for the recovery of bioethanol from the thermally sensitive fermentation broths. The technology could be controlled to give high separation and energy efficiency. This could contribute to improving commercial viability of biofuel production and other coproducts of biorefinery processing.

Unraveling the mechanisms underlying postural instability in Parkinson's disease using dynamic posturography

NARCIS (Netherlands)

Nonnekes, J.H.; Kam, D. de; Geurts, A.C.; Weerdesteijn, V.G.M.; Bloem, B.R.

2013-01-01

Postural instability, one of the cardinal symptoms of Parkinson's disease (PD), has devastating consequences for affected patients. Better strategies to prevent falls are needed, but this calls for an improved understanding of the complex mechanisms underlying postural instability. We must also

Feeding Problems and Their Underlying Mechanisms in the Esophageal Atresia–Tracheoesophageal Fistula Patient

Science.gov (United States)

Mahoney, Lisa; Rosen, Rachel

2017-01-01

Feeding difficulties such as dysphagia, coughing, choking, or vomiting during meals, slow eating, oral aversion, food refusal, and stressful mealtimes are common in children with repaired esophageal atresia (EA) and the reasons for this are often multifactorial. The aim of this review is to describe the possible underlying mechanisms contributing to feeding difficulties in patients with EA and approaches to management. Underlying mechanisms for these feeding difficulties include esophageal dysphagia, oropharyngeal dysphagia and aspiration, and aversions related to prolonged gastrostomy tube feeding. The initial diagnostic evaluation for feeding difficulties in a patient with EA may involve an esophagram, videofluoroscopic imaging or fiberoptic endoscopic evaluation during swallowing, upper endoscopy with biopsies, pH-impedance testing, and/or esophageal motility studies. The main goal of management is to reduce the factors contributing to feeding difficulties and may include reducing esophageal stasis, maximizing reflux therapies, treating underlying lung disease, dilating strictures, and altering feeding methods, routes, or schedules. PMID:28620597

Separation of uranium isotopes

International Nuclear Information System (INIS)

Ehrfeld, W.; Ehrfeld, U.

1977-01-01

In the nuclear fuel cycle, uranium enrichment is not a principal problem of technological feasibility. Several processes exist for producing LWR fuel and the enrichment method can be selected in consideration of economical, environmental, and political aspects. To date, the gaseous diffusion process constitutes the major part of enrichment capacity. This process has been well demonstrated for over 30 years and, as a matter of fact, no major technological and economical progress is to be expected in the future. Because of their comparatively high development potential, the centrifuge and the separation nozzle method may become increasingly favorable in economics. The development of the centrifuge process which is superior by its low specific energy consumption aims at technological improvements. In the separation nozzle process which offers the advantage of a comparatively simple technology a further reduction of the specific energy consumption is to be expected because of the thermodynamically favorable separation mechanism of this process. Laser isotope separation methods are still on the laboratory scale, although large financial funds have been spent. (orig.) [de

Reattachment Zone Characterisation Under Offshore Winds With Flow Separation On The Lee Side Of Coastal Dunes

Science.gov (United States)

Delgado-Fernandez, I.; Jackson, D.; Cooper, J. A.; Baas, A. C.; Lynch, K.; Beyers, M.

2010-12-01

Airflow separation, lee-side eddies and secondary flows play an essential role on the formation and maintenance of sand dunes. Downstream from dune crests the flow surface layer detaches from the ground and generates an area characterised by turbulent eddies in the dune lee slope (the wake). At some distance downstream from the dune crest, flow separates into a reversed component directed toward the dune toe and an offshore “re-attached” component. This reattachment zone (RZ) has been documented in fluvial and desert environments, wind tunnel experiments and numerical simulations, but not yet characterised in coastal dunes. This study examines the extent and temporal evolution of the RZ and its implications for beach-dune interaction at Magilligan, Northern Ireland. Wind parameters were measured over a profile extending from an 11 m height dune crest towards the beach, covering a total distance of 65 m cross-shore. Data was collected using an array of nine ultrasonic anemometers (UAs) deployed in April-May 2010, as part of a larger experiment to capture airflow data under a range of incident wind velocities and offshore directions. UAs were located along the profile (5 m tower spacing) over the beach, which allowed a detailed examination of the RZ with empirical data. Numerical modelling using Computational Fluid Dynamics (CFD) software was also conducted with input data from anemometer field measurements, running over a surface mesh generated from LiDAR and DGPS surveys. Results demonstrate that there is a wind threshold of approximately 5-6 ms-1 under which no flow separation exists with offshore winds. As wind speed increases over the threshold, a flow reversal area is quickly formed, with the maximum extent of the RZ at approximately 3.5 dune heights (h). The maximum extent of the RZ increases up to 4.5h with stronger wind speeds of 8-10 ms-1 and remains relatively constant as wind speed further increases. This suggests that the spatial extent of the RZ is

[Study on mechanism of SOM stabilization of paddy soils under long-term fertilizations].

Science.gov (United States)

Luo, Lu; Zhou, Ping; Tong, Cheng-Li; Shi, Hui; Wu, Jin-Shui; Huang, Tie-Ping

2013-02-01

Fourier transform infrared spectroscopy (FTIR) was applied to study the structure of soil organic matter (SOM) of paddy soils under long-term different fertilization treatments. The aim was to clarify the different distribution of SOM between different fertilization methods and between topsoil and subsoil, and to explore the stability mechanism of SOM under different fertilization treatments. The results showed that the content of topsoil organic carbon (SOC) was the highest under organic-inorganic fertilizations, with the increment of SOC by 18.5%, 12.9% and 18.4% under high organic manure (HOM), low organic manure (LOM) and straw returning (STW) respectively compared with no fertilization treatment (CK). The long-term fertilizations also changed the chemical structure of SOM. As compared with CK, different fertilization treatments increased the functional group absorbing intensity of chemical resistance compounds (aliphatic, aromaticity), carbohydrate and organo-silicon compounds, which was the most distinctive under treatments of HOM, LOM and STW. For example, the absorbing intensity of alkyl was 0.30, 0.25 and 0.29 under HOM, LOM and STW, respectively. These values were increased by 87% , 56% and 81% as compared with that under CK treatment. The functional group absorbing intensity of SOM in the topsoil was stronger than that in the subsoil, with the most distinctive difference under HOM, LOM and STW treatments. The present research indicated that the enhanced chemical resistance of functional group of SOM may contribute to the high contents of SOC in the paddy soils under long-term organic-inorganic fertilizations, which also suggested a chemical stabilization mechanism of SOM in the paddy soils.

Mechanical properties of cellulose electro-active paper under different environmental conditions

International Nuclear Information System (INIS)

Kim, Heung Soo; Kim, Jaehwan; Jung, Woochul; Ampofo, Joshua; Craft, William; Sankar, Jagannathan

2008-01-01

The mechanical properties of cellulose-based electro-active paper (EAPap) are investigated under various environmental conditions. Cellulose EAPap has been discovered as a smart material that can be used as both sensor and actuator. Its advantages include low voltage operation, light weight, low power consumption, biodegradability and low cost. EAPap is made with cellulose paper coated with thin electrodes. EAPap shows a reversible and reproducible bending movement as well as longitudinal displacement under an electric field. However, EAPap is a complex anisotropic material which has not been fully characterized. This study investigates the mechanical properties of cellulose-based EAPap, including Young's modulus, yield strength, ultimate strength and creep, along with orientation directions, humidity and temperature levels. To test the materials in different humidity and temperature levels, a special material testing system was made that can control the testing environmental conditions. The initial Young's modulus of EAPap is in the range of 4–9 GPa, which was higher than that of other polymer materials. Also, the Young's modulus is orientation dependent, which may be associated with the piezoelectricity of EAPap materials. The elastic strength and stiffness gradually decreased when the humidity and temperature were increased. Creep and relaxation were observed under constant stress and strain, respectively. Through scanning electron microscopy, EAPap is shown to exhibit both layered and oriented cellulose macromolecular structures that impact both the elastic and plastic behavior

Protein separations using enhanced-fluidity liquid chromatography.

Science.gov (United States)

Bennett, Raffeal; Olesik, Susan V

2017-11-10

Enhanced-fluidity liquid chromatography (EFLC) methods using methanol/H 2 O/CO 2 and hydrophilic interaction liquid chromatography (HILIC) were explored for the separation of proteins and peptides. EFLC is a separation mode that uses a mobile phase made of conventional solvents combined with liquid carbon dioxide (CO 2 ) in subcritical conditions. The addition of liquid CO 2 enhances diffusivity and decreases viscosity while maintaining mixture polarity, which typically results in reduced time of analysis. TFA additive and elevated temperature were leveraged as key factors in the separation of a 13-analyte intact protein mixture in under 5min. Under these conditions EFLC showed modest improvement in terms of peak asymmetry and analysis time over the competing ACN/H 2 O separation. Protein analytes detected by electrospray ionization - quadrupole time of flight, were shown to be unaffected by the addition of CO 2 in the mobile phase. Herein, the feasibility of separating hydrophilic proteins up to 80kDa (with transferrin) is demonstrated for CO 2 -containing mobile phases. Copyright © 2017 Elsevier B.V. All rights reserved.

Deterioration of mechanical properties of high strength structural steel S460N under transient state fire condition

International Nuclear Information System (INIS)

Qiang, Xuhong; Bijlaard, Frans S.K.; Kolstein, Henk

2012-01-01

Highlights: ► Mechanical properties of S460N under transient state fire condition are obtained. ► Elevated-temperature mechanical properties of steels are dependent on steel grades. ► No design standard is applicable to HSS S460N under transient state fire condition. ► Specific statements on various HSS in fire should be proposed in design standards. ► Research results offer accurate material property for structural design engineers. -- Abstract: 911 World Trade Centre Tragedy put fire safety of constructional steel structures into question. Since then, more and more research attention has been paid to the elevated-temperature mechanical properties of structural steels, which is a critical basis of evaluating the fire performance of steel structures. In the literature the available mechanical properties of structural steels under fire conditions were mainly obtained from steady state test method, as steady state test method is easier to perform than transient state test method and offers stress–strain curves directly. However, the transient state fire condition is considered to be more realistic to represent the real condition when constructions are exposed to fire. In order to reveal the deterioration of mechanical properties of the commonly used high strength structural steel S460N under transient state fire condition, tensile tests were conducted under various constant stress levels up to 800 MPa. The reduction factors of elastic modulus, yield and ultimate strengths of S460N under transient state fire condition were obtained and compared with current leading design standards and available literature. The application of such accurate elevated-temperature mechanical properties reduction factors of S460N can ensure a safe fire-resistance design and evaluation of steel structures with high strength steel S460N under transient state fire condition. This experimental study also supports other relative research on fire performance of steel structures with

Non-relativistic quantum mechanics

CERN Document Server

Puri, Ravinder R

2017-01-01

This book develops and simplifies the concept of quantum mechanics based on the postulates of quantum mechanics. The text discusses the technique of disentangling the exponential of a sum of operators, closed under the operation of commutation, as the product of exponentials to simplify calculations of harmonic oscillator and angular momentum. Based on its singularity structure, the Schrödinger equation for various continuous potentials is solved in terms of the hypergeometric or the confluent hypergeometric functions. The forms of the potentials for which the one-dimensional Schrödinger equation is exactly solvable are derived in detail. The problem of identifying the states of two-level systems which have no classical analogy is addressed by going beyond Bell-like inequalities and separability. The measures of quantumness of mutual information in two two-level systems is also covered in detail. Offers a new approach to learning quantum mechanics based on the history of quantum mechanics and its postu...

How diagnostic tests help to disentangle the mechanisms underlying neuropathic pain symptoms in painful neuropathies.

Science.gov (United States)

Truini, Andrea; Cruccu, Giorgio

2016-02-01

Neuropathic pain, ie, pain arising directly from a lesion or disease affecting the somatosensory afferent pathway, manifests with various symptoms, the commonest being ongoing burning pain, electrical shock-like sensations, and dynamic mechanical allodynia. Reliable insights into the mechanisms underlying neuropathic pain symptoms come from diagnostic tests documenting and quantifying somatosensory afferent pathway damage in patients with painful neuropathies. Neurophysiological investigation and skin biopsy studies suggest that ongoing burning pain primarily reflects spontaneous activity in nociceptive-fiber pathways. Electrical shock-like sensations presumably arise from high-frequency ectopic bursts generated in demyelinated, nonnociceptive, Aβ fibers. Although the mechanisms underlying dynamic mechanical allodynia remain debatable, normally innocuous stimuli might cause pain by activating spared and sensitized nociceptive afferents. Extending the mechanistic approach to neuropathic pain symptoms might advance targeted therapy for the individual patient and improve testing for new drugs.

Separation control on the wing by jet actuators

Science.gov (United States)

Karyakin, O. M.; Nalivaiko, A. G.; Ustinov, M. V.; Flaxman, Ja. Sh.

2018-05-01

Use of jet actuators to eliminate flow separation is experimentally investigated on a straight wing with a NACA 0012 airfoil. It is shown that under the influence of synthetic jets the size of separation zone greatly reduces and the flow separation point displaces downstream. In addition, lift coefficient increases by more than 10%.

Different underlying mechanisms for face emotion and gender processing during feature-selective attention: Evidence from event-related potential studies.

Science.gov (United States)

Wang, Hailing; Ip, Chengteng; Fu, Shimin; Sun, Pei

2017-05-01

Face recognition theories suggest that our brains process invariant (e.g., gender) and changeable (e.g., emotion) facial dimensions separately. To investigate whether these two dimensions are processed in different time courses, we analyzed the selection negativity (SN, an event-related potential component reflecting attentional modulation) elicited by face gender and emotion during a feature selective attention task. Participants were instructed to attend to a combination of face emotion and gender attributes in Experiment 1 (bi-dimensional task) and to either face emotion or gender in Experiment 2 (uni-dimensional task). The results revealed that face emotion did not elicit a substantial SN, whereas face gender consistently generated a substantial SN in both experiments. These results suggest that face gender is more sensitive to feature-selective attention and that face emotion is encoded relatively automatically on SN, implying the existence of different underlying processing mechanisms for invariant and changeable facial dimensions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coexistence of Strategic Vertical Separation and Integration

DEFF Research Database (Denmark)

Jansen, Jos

2003-01-01

This paper gives conditions under which vertical separation is chosen by some upstream firms, while vertical integration is chosen by others in the equilibrium of a symmetric model. A vertically separating firm trades off fixed contracting costs against the strategic benefit of writing a (two......-part tariff, exclusive dealing) contract with its retailer. Coexistence emerges when more than two vertical Cournot oligopolists supply close substitutes. When vertical integration and separation coexist, welfare could be improved by reducing the number of vertically separating firms. The scope...

The role of interfacial water layer in atmospherically relevant charge separation

Science.gov (United States)

Bhattacharyya, Indrani

Charge separation at interfaces is important in various atmospheric processes, such as thunderstorms, lightning, and sand storms. It also plays a key role in several industrial processes, including ink-jet printing and electrostatic separation. Surprisingly, little is known about the underlying physics of these charging phenomena. Since thin films of water are ubiquitous, they may play a role in these charge separation processes. This talk will focus on the experimental investigation of the role of a water adlayer in interfacial charging, with relevance to meteorologically important phenomena, such as atmospheric charging due to wave actions on oceans and sand storms. An ocean wave generates thousands of bubbles, which upon bursting produce numerous large jet droplets and small film droplets that are charged. In the 1960s, Blanchard showed that the jet droplets are positively charged. However, the charge on the film droplets was not known. We designed an experiment to exclusively measure the charge on film droplets generated by bubble bursting on pure water and aqueous salt solution surfaces. We measured their charge to be negative and proposed a model where a slight excess of hydroxide ions in the interfacial water layer is responsible for generating these negatively charged droplets. The findings from this research led to a better understanding of the ionic disposition at the air-water interface. Sand particles in a wind-blown sand layer, or 'saltation' layer, become charged due to collisions, so much so, that it can cause lightning. Silica, being hydrophilic, is coated with a water layer even under low-humidity conditions. To investigate the importance of this water adlayer in charging the silica surfaces, we performed experiments to measure the charge on silica surfaces due to contact and collision processes. In case of contact charging, the maximum charge separation occurred at an optimum relative humidity. On the contrary, in collisional charging process, no

Risks and chances of combined forestry and biomass projects under the Clean Development Mechanism

Energy Technology Data Exchange (ETDEWEB)

Dutschke, Michael; Kapp, Gerald; Lehmann, Anna; Schaefer, Volkmar (Hamburg Inst. International Economics (Germany))

2006-06-15

The Clean Development Mechanism (CDM) aims at reducing greenhouse gas (GHG) emissions, while at the same time taking up CO{sub 2} from the atmosphere in vegetation by means of afforestation and reforestation. In spite of these options being complementary, rules and modalities for both project classes are being treated separately in the relevant decisions by the Conference of the Parties to the UN Framework Convention on Climate Change. The present study reviews the state of bioenergy use in developing countries, modalities and procedures under the CDM, and the potential for transaction cost reduction in climate mitigation projects. There are four potential types of combinations in the matrix between small-scale - large-scale / afforestation and reforestation - bioenergy activities. We develop criteria for assessing sustainable development benefits and present an example project for each of the potential project types. We find that the individual risks of single-category projects do not increase when combining project categories and that each combination holds potential for integrated sustainability benefits. Risks for local livelihoods do increase with project size, but a transparent, participatory planning phase is able to counterbalance smallholders' lack of negotiation power. Further research will have to develop concrete project examples and blueprints with approved CDM methodologies, thereby decreasing transaction costs and risk for all potential project partners. (au)

Mechanisms of astrocytic K(+) clearance and swelling under high extracellular K(+) concentrations.

Science.gov (United States)

Murakami, Shingo; Kurachi, Yoshihisa

2016-03-01

In response to the elevation of extracellular K(+) concentration ([K(+)]out), astrocytes clear excessive K(+) to maintain conditions necessary for neural activity. K(+) clearance in astrocytes occurs via two processes: K(+) uptake and K(+) spatial buffering. High [K(+)]out also induces swelling in astrocytes, leading to edema and cell death in the brain. Despite the importance of astrocytic K(+) clearance and swelling, the underlying mechanisms remain unclear. Here, we report results from a simulation analysis of astrocytic K(+) clearance and swelling. Astrocyte models were constructed by incorporating various mechanisms such as intra/extracellular ion concentrations of Na(+), K(+), and Cl(-), cell volume, and models of Na,K-ATPase, Na-K-Cl cotransporter (NKCC), K-Cl cotransporter, inwardly-rectifying K(+) (KIR) channel, passive Cl(-) current, and aquaporin channel. The simulated response of astrocyte models under the uniform distribution of high [K(+)]out revealed significant contributions of NKCC and Na,K-ATPase to increases of intracellular K(+) and Cl(-) concentrations, and swelling. Moreover, we found that, under the non-uniform distribution of high [K(+)]out, KIR channels localized at synaptic clefts absorbed excess K(+) by depolarizing the equivalent potential of K(+) (E K) above membrane potential, while K(+) released through perivascular KIR channels was enhanced by hyperpolarizing E K and depolarizing membrane potential. Further analysis of simulated drug effects revealed that astrocyte swelling was modulated by blocking each of the ion channels and transporters. Our simulation analysis revealed controversial mechanisms of astrocytic K(+) clearance and swelling resulting from complex interactions among ion channels and transporters.

Detailed monitoring of two biogas plants and mechanical solid-liquid separation of fermentation residues.

Science.gov (United States)

Bauer, Alexander; Mayr, Herwig; Hopfner-Sixt, Katharina; Amon, Thomas

2009-06-01

The Austrian "green electricity act" (Okostromgesetz) has led to an increase in biogas power plant size and consequently to an increased use of biomass. A biogas power plant with a generating capacity of 500 kW(el) consumes up to 38,000 kg of biomass per day. 260 ha of cropland is required to produce this mass. The high water content of biomass necessitates a high transport volume for energy crops and fermentation residues. The transport and application of fermentation residues to farmland is the last step in this logistic chain. The use of fermentation residues as fertilizer closes the nutrient cycle and is a central element in the efficient use of biomass for power production. Treatment of fermentation residues by separation into liquid and solid phases may be a solution to the transport problem. This paper presents detailed results from the monitoring of two biogas plants and from the analysis of the separation of fermentation residues. Furthermore, two different separator technologies for the separation of fermentation residues of biogas plants were analyzed. The examined biogas plants correspond to the current technological state of the art and have designs developed specifically for the utilization of energy crops. The hydraulic retention time ranged between 45.0 and 83.7 days. The specific methane yields were 0.40-0.43 m(3)N CH(4) per kg VS. The volume loads ranged between 3.69 and 4.00 kg VS/m(3). The degree of degradation was between 77.3% and 82.14%. The screw extractor separator was better suited for biogas slurry separation than the rotary screen separator. The screw extractor separator exhibited a high throughput and good separation efficiency. The efficiency of slurry separation depended on the dry matter content of the fermentation residue. The higher the dry matter content, the higher the proportion of solid phase after separation. In this project, we found that the fermentation residues could be divided into 79.2% fluid phase with a dry matter

Mathematics model of filtration efficiency of moisture separator for nuclear reactors

International Nuclear Information System (INIS)

Zhang Zhenzhong; Jiang Feng; Huang Yunfeng

2010-01-01

In order to study the filtration mechanism of the moisture separator for water droplet of 5∼10μm, this paper set up a physical model. For the mixed meshes, they can be classified into three types: standard meshes, bur meshes and middle meshes. For all fibers of the wire meshes and vertical fibers of standard mixed meshes, a Kuwabara flow field is used to track the particle to get the inertial impaction efficiency and then calculate the total filtration efficiency of the meshes. For other fibers, besides the Kuwabara flow field, an around-flat flow field is added to calculate the efficiency. Lastly, the total efficiency of the moisture separator according to the equation of the filtration efficiency for the filters in series is compared with the experimental data. The result shows that, under the standard condition,the calculation value is consistent with the experimental efficiency data. (authors)

Molecular Modeling Study of Chiral Separation and Recognition Mechanism of β-Adrenergic Antagonists by Capillary Electrophoresis

Directory of Open Access Journals (Sweden)

Yifeng Chai

2012-01-01

Full Text Available Chiral separations of five β-adrenergic antagonists (propranolol, esmolol, atenolol, metoprolol, and bisoprolol were studied by capillary electrophoresis using six cyclodextrins (CDs as the chiral selectors. Carboxymethylated-β-cyclodextrin (CM-β-CD exhibited a higher enantioselectivity power compared to the other tested CDs. The influences of the concentration of CM-β-CD, buffer pH, buffer concentration, temperature, and applied voltage were investigated. The good chiral separation of five β-adrenergic antagonists was achieved using 50 mM Tris buffer at pH 4.0 containing 8 mM CM-β-CD with an applied voltage of 24 kV at 20 °C. In order to understand possible chiral recognition mechanisms of these racemates with CM-β-CD, host-guest binding procedures of CM-β-CD and these racemates were studied using the molecular docking software Autodock. The binding free energy was calculated using the Autodock semi-empirical binding free energy function. The results showed that the phenyl or naphthyl ring inserted in the hydrophobic cavity of CM-β-CD and the side chain was found to point out of the cyclodextrin rim. Hydrogen bonding between CM-β-CD and these racemates played an important role in the process of enantionseparation and a model of the hydrogen bonding interaction positions was constructed. The difference in hydrogen bonding formed with the –OH next to the chiral center of the analytes may help to increase chiral discrimination and gave rise to a bigger separation factor. In addition, the longer side chain in the hydrophobic phenyl ring of the enantiomer was not beneficial for enantioseparation and the chiral selectivity factor was found to correspond to the difference in binding free energy.

A novel process for separation of hazardous poly(vinyl chloride) from mixed plastic wastes by froth flotation.

Science.gov (United States)

Wang, Jianchao; Wang, Hui; Wang, Chongqing; Zhang, Lingling; Wang, Tao; Zheng, Long

2017-11-01

A novel method, calcium hypochlorite (CHC) treatment, was proposed for separation of hazardous poly(vinyl chloride) (PVC) plastic from mixed plastic wastes (MPWs) by froth flotation. Flotation behavior of single plastic indicates that PVC can be separated from poly(ethylene terephthalate) (PET), poly(acrylonitrile-co-butadiene-co-styrene) (ABS), polystyrene (PS), polycarbonate (PC) and poly(methyl methacrylate) (PMMA) by froth flotation combined with CHC treatment. Mechanism of CHC treatment was examined by contact angle measurement, scanning electron microscopy, Fourier transform infrared and X-ray photoelectron spectroscopy. Under the optimum conditions, separation of PVC from binary plastics with different particle sizes is achieved efficiently. The purity of PC, ABS, PMMA, PS and PET is greater than 96.8%, 98.5%, 98.8%, 97.4% and 96.3%, respectively. Separation of PVC from multi-plastics was further conducted by two-stage flotation. PVC can be separated efficiently from MPWs with residue content of 0.37%. Additionally, reusing CHC solution is practical. This work indicates that separation of hazardous PVC from MPWs is effective by froth flotation. Copyright © 2017 Elsevier Ltd. All rights reserved.

Microscale failure mechanisms leading to internal short circuit in Li-ion batteries under complex loading scenarios

NARCIS (Netherlands)

Sahraei, E.; Bosco, E.; Dixon, B.; Lai, B.

2016-01-01

One of the least understood mechanisms of Li-ion batteries is the development of internal short circuits under mechanical loads. In this study, a micro mechanical model is developed and subjected to various loading scenarios to understand the sequence of failure in the multi-layer, multi-material

Evolution of the bonding mechanism of ZnO under isotropic compression: A first-principles study

International Nuclear Information System (INIS)

Zhou, G.C.; Sun, L.Z.; Wang, J.B.; Zhong, X.L.; Zhou, Y.C.

2008-01-01

The electronic structure and the bonding mechanism of ZnO under isotropic pressure have been studied by using the full-potential linear augmented plane wave (FP-LAPW) method within the density-functional theory (DFT) based on LDA+U exchange correlation (EXC) potential. We used the theory of Atoms in Molecules (AIM) method to analyze the change of the charge transfer and the bonding strength under isotropic pressure. The results of the theoretical analysis show that charge transfer between Zn and O atomic basins nearly linearly increases with the increasing pressure. Charge density along the Zn-O bond increases under the high pressure. The bonding strength and the ionicity of Zn-O bond also increase with the increasing pressure. The linear evolution process of the bonding mechanism under isotropic pressure was shown clearly in the present paper

The pathologic mechanisms underlying lumbar distraction spinal cord injury in rabbits.

Science.gov (United States)

Wu, Di; Zheng, Chao; Wu, Ji; Xue, Jing; Huang, Rongrong; Wu, Di; Song, Yueming

2017-11-01

A reliable experimental rabbit model of distraction spinal cord injury (SCI) was established to successfully simulate gradable and replicable distraction SCI. However, further research is needed to elucidate the pathologic mechanisms underlying distraction SCI. The aim of this study was to investigate the pathologic mechanisms underlying lumbar distraction SCI in rabbits. This is an animal laboratory study. Using a self-designed spine distractor, the experimental animals were divided into a control group and 10%, 20%, and 30% distraction groups. Pathologic changes to the spinal cord microvessels in the early stage of distraction SCI were identified by perfusion of the spinal cord vasculature with ink, production of transparent specimens, observation by light microscopy, and observation of corrosion casts of the spinal cord microvascular architecture by scanning electron microscopy. Malondialdehyde (MDA) and superoxide dismutase (SOD) concentrations in the injured spinal cord tissue were measured after 8 hours. With an increasing degree and duration of distraction, the spinal cord microvessels were only partially filled and had the appearance of spasm until rupture and hemorrhage were observed. The MDA concentration increased and the SOD concentration decreased in the spinal cord tissue. Changes to the internal and external spinal cord vessels led to spinal cord ischemia, which is a primary pathologic mechanism of distraction SCI. Lipid peroxidation mediated by free radicals took part in secondary pathologic damage of distraction SCI. Copyright © 2017 Elsevier Inc. All rights reserved.

Mechanisms for closing bores and releasably securing articles within the bores under longitudinal load

International Nuclear Information System (INIS)

Klahn, F.C.; Nolan, J.H.; Wills, C.

1979-01-01

This invention relates to mechanisms for closing bores of tubular passages and for releasably securing articles within the bores under longitudinal load. The system includes an axially movable latch, an actuator and locking devices. Embodiments of the invention can be used as closure mechanisms for tubular irradiation surveillance specimen assembly holders used in nuclear reactors. (UK)

Mechanisms for closing bores and releasably securing articles within the bores under longitudinal load

International Nuclear Information System (INIS)

Kalen, D.D.; Mitchem, J.W.

1979-01-01

This invention relates to mechanisms for closing bores of tubular passages and for releasably securing articles within the bores under longitudinal load. The system includes an axially movable actuator and a latch which engages the tubular opening. Embodiments of the invention can be used as closure mechanisms for tubular irradiation surveillance specimen assembly holders used in nuclear reactors. (UK)

Nonlinear Dynamic Analysis of Telescopic Mechanism for Truss Structure Bridge Inspection Vehicle Under Pedestrian Excitation

Directory of Open Access Journals (Sweden)

Wenwen Sui

Full Text Available Abstract Nonlinear dynamic analysis of an axially moving telescopic mechanism for truss structure bridge inspection vehicle under pedestrian excitation is carried out. A biomechanically inspired inverted-pendulum model is utilized to simplify the pedestrian. The nonlinear equations of motion for the beam-pedestrian system are derived using the Hamilton's principle. The equations are transformed into two ordinary differential equations by applying the Galerkin's method at the first two orders. The solutions to the equations are acquired by using the Newmark-β method associated with the Newton-Raphson method. The time-dependent feature of the eigenfunctions for the two beams are taken into consideration in the solutions. Accordingly, the equations of motion for a simplified system, in which the pedestrian is regarded as moving cart, are given. In the numerical examples, dynamic responses of the telescopic mechanism in eight conditions of different beam-telescoping and pedestrian-moving directions are simulated. Comparisons between the vibrations of the beams under pedestrian excitation and corresponding moving cart are carried out to investigate the influence of the pedestrian excitation on the telescopic mechanism. The results show that the displacement of the telescopic mechanism under pedestrian excitation is smaller than that under moving cart especially when the pedestrian approaches the beams end. Additionally, compared with moving cart, the pedestrian excitation can effectively strengthen the vibration when the beam extension is small or when the pedestrian is close to the beams end.

An Investigation of the Mechanism Underlying Teacher Aggression: Testing I[superscript 3] Theory and the General Aggression Model

Science.gov (United States)

Montuoro, Paul; Mainhard, Tim

2017-01-01

Background: Considerable research has investigated the deleterious effects of teachers responding aggressively to students who misbehave, but the mechanism underlying this dysfunctional behaviour remains unknown. Aims: This study investigated whether the mechanism underlying teacher aggression follows I[superscript 3] theory or General Aggression…

Cyclic life of superalloy IN738LC under in-phase and out-of-phase thermo-mechanical fatigue loading

International Nuclear Information System (INIS)

Chen Hongjun; Wahi, R.P.; Wever, H.

1995-01-01

The cyclic life of IN738LC, a widely used nickel base superalloy for blades in stationary gas turbines, was investigated under thermo-mechanical fatigue loading using a temperature variation range of 1023 to 1223 K, with temperature variation rate in the range of 6 to 15 K/min. Simple thermo-mechanical cycles with linear sequences corresponding to in-phase (IP) and out-of-phase (OP) tests were performed. Both the IP and OP tests were carried out at different constant mechanical strain ranges varied between 0.8 to 2.0% and at a constant mechanical strain rate of 10 -5 s -1 . Thermo-mechanical fatigue lives under both test conditions were compared with each other and with those of isothermal LCF tests at a temperature of 1223 K. The results show that the life under thermo-mechanical fatigue is strongly dependent on the nature of the test, i.e. stress controlled or strain controlled. (orig.)

Isotopic separation of carbon by dissociation of CF2HCl irradiated by a Q-modulated CO2 laser

International Nuclear Information System (INIS)

Ezubchenko, A.N.; Ilyukhin, A.I.; Karchevskii, A.I.; Krasnikov, N.S.; Merzylakov, A.V.; Soloukhin, A.B.

1993-01-01

Isotopic separation of carbon by selective dissociation of CF 2 HCl by radiation from a CO 2 laser with mechanical Q-modulation has been studied experimentally. The modulation frequency was 10 4 sec -1 with a 20 W output. The peak radiation intensity is increased by a factor of 20-100 when modulated, while the average power is 0.5-0.9 that of the laser when operating in continuous mode. The authors show that under these conditions, a separation coefficient on the order of 40-50 is achieved as well as a high degree of the target isotope extraction (70%)

Dual magnetic separator for TRIμP

International Nuclear Information System (INIS)

Berg, G.P.A.; Dermois, O.C.; Dammalapati, U.; Dendooven, P.; Harakeh, M.N.; Jungmann, K.; Onderwater, C.J.G.; Rogachevskiy, A.; Sohani, M.; Traykov, E.; Willmann, L.; Wilschut, H.W.

2006-01-01

The TRIμP facility, under construction at KVI, requires the production and separation of short-lived and rare isotopes. Direct reactions, fragmentation and fusion-evaporation reactions in normal and inverse kinematics are foreseen to produce nuclides of interest with a variety of heavy-ion beams from the superconducting cyclotron AGOR. For this purpose, we have designed, constructed and commissioned a versatile magnetic separator that allows efficient injection into an ion catcher, i.e., gas-filled stopper/cooler or thermal ionizer, from which a low energy radioactive beam will be extracted. The separator performance was tested with the production and clean separation of 21 Na ions, where a beam purity of 99.5% could be achieved. For fusion-evaporation products, some of the features of its operation as a gas-filled recoil separator were tested

Nanomaterials modulate stem cell differentiation: biological interaction and underlying mechanisms.

Science.gov (United States)

Wei, Min; Li, Song; Le, Weidong

2017-10-25

Stem cells are unspecialized cells that have the potential for self-renewal and differentiation into more specialized cell types. The chemical and physical properties of surrounding microenvironment contribute to the growth and differentiation of stem cells and consequently play crucial roles in the regulation of stem cells' fate. Nanomaterials hold great promise in biological and biomedical fields owing to their unique properties, such as controllable particle size, facile synthesis, large surface-to-volume ratio, tunable surface chemistry, and biocompatibility. Over the recent years, accumulating evidence has shown that nanomaterials can facilitate stem cell proliferation and differentiation, and great effort is undertaken to explore their possible modulating manners and mechanisms on stem cell differentiation. In present review, we summarize recent progress in the regulating potential of various nanomaterials on stem cell differentiation and discuss the possible cell uptake, biological interaction and underlying mechanisms.

Mechanisms Underlying HIV-Associated Noninfectious Lung Disease.

Science.gov (United States)

Presti, Rachel M; Flores, Sonia C; Palmer, Brent E; Atkinson, Jeffrey J; Lesko, Catherine R; Lau, Bryan; Fontenot, Andrew P; Roman, Jesse; McDyer, John F; Twigg, Homer L

2017-11-01

Pulmonary disease remains a primary source of morbidity and mortality in persons living with HIV (PLWH), although the advent of potent combination antiretroviral therapy has resulted in a shift from predominantly infectious to noninfectious pulmonary complications. PLWH are at high risk for COPD, pulmonary hypertension, and lung cancer even in the era of combination antiretroviral therapy. The underlying mechanisms of this are incompletely understood, but recent research in both human and animal models suggests that oxidative stress, expression of matrix metalloproteinases, and genetic instability may result in lung damage, which predisposes PLWH to these conditions. Some of the factors that drive these processes include tobacco and other substance use, direct HIV infection and expression of specific HIV proteins, inflammation, and shifts in the microbiome toward pathogenic and opportunistic organisms. Further studies are needed to understand the relative importance of these factors to the development of lung disease in PLWH. Copyright © 2017 American College of Chest Physicians. Published by Elsevier Inc. All rights reserved.

Autophagy as a Possible Underlying Mechanism of Nanomaterial Toxicity

Directory of Open Access Journals (Sweden)

Vanessa Cohignac

2014-07-01

Full Text Available The rapid development of nanotechnologies is raising safety concerns because of the potential effects of engineered nanomaterials on human health, particularly at the respiratory level. Since the last decades, many in vivo studies have been interested in the pulmonary effects of different classes of nanomaterials. It has been shown that some of them can induce toxic effects, essentially depending on their physico-chemical characteristics, but other studies did not identify such effects. Inflammation and oxidative stress are currently the two main mechanisms described to explain the observed toxicity. However, the exact underlying mechanism(s still remain(s unknown and autophagy could represent an interesting candidate. Autophagy is a physiological process in which cytoplasmic components are digested via a lysosomal pathway. It has been shown that autophagy is involved in the pathogenesis and the progression of human diseases, and is able to modulate the oxidative stress and pro-inflammatory responses. A growing amount of literature suggests that a link between nanomaterial toxicity and autophagy impairment could exist. In this review, we will first summarize what is known about the respiratory effects of nanomaterials and we will then discuss the possible involvement of autophagy in this toxicity. This review should help understand why autophagy impairment could be taken as a promising candidate to fully understand nanomaterials toxicity.

An application of liquid sublayer dryout mechanism to the prediction of critical heat flux under low pressure and low velocity conditions in round tubes

International Nuclear Information System (INIS)

Lee, Kwang-Won; Yang, Jae-Young; Baik, Se-Jin

1997-01-01

Based on several experimental evidences for nucleate boiling in annular film and the existence of residual liquid film flow rate at the critical heat flux (CHF) location, the liquid sublayer dryout (LSD) mechanism under annular film is firstly introduced to evaluate the CHF data at low pressure and low velocity (LPLV) conditions, which would not be predicted by a normal annular film dryout (AFD) model. In this study, the CHF occurrence due to annular film separation or breaking down is phenomenologically modelled by applying the LSD mechanism to this situation. In this LSD mechanism, the liquid sublayer thickness, the incoming liquid velocity to the liquid sublayer, and the axial distance from the onset of annular flow to the CHF location are used as the phenomena-controlling parameters. From the model validation on the 1406 CHF data points ranging over P = 0.1 - 2 MPa, G = 4 - 499 kg/m 2 s, L/D = 4 - 402, most of CHF data (more than 1000 points) are predicted within ±30% error bounds by the LSD mechanism. However, some calculation results that critical qualities are less than 0.4 are considerably overestimated by this mechanism. These overpredictions seem to be caused by inadequate CHF mechanism classification criteria and an insufficient consideration of the flow instability effect on CHF. Further studies for a new classification criterion screening the CHF data affected by flow instabilities and a new bubble detachment model for LPLV conditions are needed to improve the model accuracy. (author)

Issues related to cooperative implementation mechanisms

International Nuclear Information System (INIS)

1998-01-01

This note by the secretariat seeks to focus discussions on some key issues regarding the design and functioning of the three new mechanisms, such as issues concerning mandates, cross-cutting as well as issues concerning individual mechanisms. The note addresses each mechanism separately in view of different origins, approaches, participants and possible applications. Reference is, however, made to similarities among the mechanisms, in particular where coordination of work on methodological and institutional issues and inter-institutional collaboration are concerned. The note suggests, in its concluding part, elements of a work programme up to and, to some extent, beyond COP 4. It draws upon the views submitted by Parties (document FCCC/SB/1998/MISC.1), contains reflections by the secretariat and builds on its consultations with other organizations having activities, under way or planned, that could contribute to the design or operation of the mechanisms. (au)

Gas separation using porous cement membrane.

Science.gov (United States)

Zhang, Weiqi; Gaggl, Maria; Gluth, Gregor J G; Behrendt, Frank

2014-01-01

Gas separation is a key issue in various industrial fields. Hydrogen has the potential for application in clean fuel technologies. Therefore, the separation and purification of hydrogen is an important research subject. CO2 capture and storage have important roles in "green chemistry". As an effective clean technology, gas separation using inorganic membranes has attracted much attention in the last several decades. Membrane processes have many applications in the field of gas separation. Cement is one type of inorganic material, with the advantages of a lower cost and a longer lifespan. An experimental setup has been created and improved to measure twenty different cement membranes. The purpose of this work was to investigate the influence of gas molecule properties on the material transport and to explore the influence of operating conditions and membrane composition on separation efficiency. The influences of the above parameters are determined, the best conditions and membrane type are found, it is shown that cementitious material has the ability to separate gas mixtures, and the gas transport mechanism is studied.

Triboelectrostatic separation for granular plastic waste recycling: a review.

Science.gov (United States)

Wu, Guiqing; Li, Jia; Xu, Zhenming

2013-03-01

The world's plastic consumption has increased incredibly in recent decades, generating more and more plastic waste, which makes it a great public concern. Recycling is the best treatment for plastic waste since it cannot only reduce the waste but also reduce the consumption of oil for producing new virgin plastic. Mechanical recycling is recommended for plastic waste to avoid the loss of its virgin value. As a mechanical separation technology, triboelectrostatic separation utilizes the difference between surface properties of different materials to get them oppositely charged, deflected in the electric field and separately collected. It has advantages such as high efficiency, low cost, no concern of water disposal or secondary pollution and a relatively wide processing range of particle size especially suitable for the granular plastic waste. The process of triboelectrostatic separation for plastic waste is reviewed in this paper. Different devices have been developed and proven to be effective for separation of plastic waste. The influence factors are also discussed. It can be concluded that the triboelectrostatic separation of plastic waste is a promising technology. However, more research is required before it can be widely applied in industry. Copyright © 2012 Elsevier Ltd. All rights reserved.

Understanding and imitating unfamiliar actions: distinct underlying mechanisms.

Directory of Open Access Journals (Sweden)

Joana C Carmo

Full Text Available The human "mirror neuron system" has been proposed to be the neural substrate that underlies understanding and, possibly, imitating actions. However, since the brain activity with mirror properties seems insufficient to provide a good description for imitation of actions outside one's own repertoire, the existence of supplementary processes has been proposed. Moreover, it is unclear whether action observation requires the same neural mechanisms as the explicit access to their meaning. The aim of this study was two-fold as we investigated whether action observation requires different processes depending on 1 whether the ultimate goal is to imitate or understand the presented actions and 2 whether the to-be-imitated actions are familiar or unfamiliar to the subject. Participants were presented with both meaningful familiar actions and meaningless unfamiliar actions that they had to either imitate or discriminate later. Event-related Potentials were used as differences in brain activity could have been masked by the use of other techniques with lower temporal resolution. In the imitation task, a sustained left frontal negativity was more pronounced for meaningless actions than for meaningful ones, starting from an early time-window. Conversely, observing unfamiliar versus familiar actions with the intention of discriminating them led to marked differences over right centro-posterior scalp regions, in both middle and latest time-windows. These findings suggest that action imitation and action understanding may be sustained by dissociable mechanisms: while imitation of unfamiliar actions activates left frontal processes, that are likely to be related to learning mechanisms, action understanding involves dedicated operations which probably require right posterior regions, consistent with their involvement in social interactions.

Estimation of Separation Buffers for Wind-Prediction Error in an Airborne Separation Assistance System

Science.gov (United States)

Consiglio, Maria C.; Hoadley, Sherwood T.; Allen, B. Danette

2009-01-01

Wind prediction errors are known to affect the performance of automated air traffic management tools that rely on aircraft trajectory predictions. In particular, automated separation assurance tools, planned as part of the NextGen concept of operations, must be designed to account and compensate for the impact of wind prediction errors and other system uncertainties. In this paper we describe a high fidelity batch simulation study designed to estimate the separation distance required to compensate for the effects of wind-prediction errors throughout increasing traffic density on an airborne separation assistance system. These experimental runs are part of the Safety Performance of Airborne Separation experiment suite that examines the safety implications of prediction errors and system uncertainties on airborne separation assurance systems. In this experiment, wind-prediction errors were varied between zero and forty knots while traffic density was increased several times current traffic levels. In order to accurately measure the full unmitigated impact of wind-prediction errors, no uncertainty buffers were added to the separation minima. The goal of the study was to measure the impact of wind-prediction errors in order to estimate the additional separation buffers necessary to preserve separation and to provide a baseline for future analyses. Buffer estimations from this study will be used and verified in upcoming safety evaluation experiments under similar simulation conditions. Results suggest that the strategic airborne separation functions exercised in this experiment can sustain wind prediction errors up to 40kts at current day air traffic density with no additional separation distance buffer and at eight times the current day with no more than a 60% increase in separation distance buffer.

The mechanism underlying fast germination of tomato cultivar LA2711.

Science.gov (United States)

Yang, Rongchao; Chu, Zhuannan; Zhang, Haijun; Li, Ying; Wang, Jinfang; Li, Dianbo; Weeda, Sarah; Ren, Shuxin; Ouyang, Bo; Guo, Yang-Dong

2015-09-01

Seed germination is important for early plant morphogenesis as well as abiotic stress tolerance, and is mainly controlled by the phytohormones abscisic acid (ABA) and gibberellic acid (GA). Our previous studies identified a salt-tolerant tomato cultivar, LA2711, which is also a fast-germinating genotype, compared to its salt-sensitive counterpart, ZS-5. In an effort to further clarify the mechanism underlying this phenomenon, we compared the dynamic levels of ABA and GA4, the transcript abundance of genes involved in their biosynthesis and catabolism as well as signal transduction between the two cultivars. In addition, we tested seed germination sensitivity to ABA and GAs. Our results revealed that insensitivity of seed germination to exogenous ABA and low ABA content in seeds are the physiological mechanisms conferring faster germination rates of LA2711 seeds. SlCYP707A2, which encodes an ABA catabolic enzyme, may play a decisive role in the fast germination rate of LA2711, as it showed a significantly higher level of expression in LA2711 than ZS-5 at most time points tested during germination. The current results will enable us to gain insight into the mechanism(s) regarding seed germination of tomato and the role of fast germination in stress tolerance. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Handedness is related to neural mechanisms underlying hemispheric lateralization of face processing

Science.gov (United States)

Frässle, Stefan; Krach, Sören; Paulus, Frieder Michel; Jansen, Andreas

2016-06-01

While the right-hemispheric lateralization of the face perception network is well established, recent evidence suggests that handedness affects the cerebral lateralization of face processing at the hierarchical level of the fusiform face area (FFA). However, the neural mechanisms underlying differential hemispheric lateralization of face perception in right- and left-handers are largely unknown. Using dynamic causal modeling (DCM) for fMRI, we aimed to unravel the putative processes that mediate handedness-related differences by investigating the effective connectivity in the bilateral core face perception network. Our results reveal an enhanced recruitment of the left FFA in left-handers compared to right-handers, as evidenced by more pronounced face-specific modulatory influences on both intra- and interhemispheric connections. As structural and physiological correlates of handedness-related differences in face processing, right- and left-handers varied with regard to their gray matter volume in the left fusiform gyrus and their pupil responses to face stimuli. Overall, these results describe how handedness is related to the lateralization of the core face perception network, and point to different neural mechanisms underlying face processing in right- and left-handers. In a wider context, this demonstrates the entanglement of structurally and functionally remote brain networks, suggesting a broader underlying process regulating brain lateralization.

Robust and Elastic Polymer Membranes with Tunable Properties for Gas Separation.

Science.gov (United States)

Cao, Peng-Fei; Li, Bingrui; Hong, Tao; Xing, Kunyue; Voylov, Dmitry N; Cheng, Shiwang; Yin, Panchao; Kisliuk, Alexander; Mahurin, Shannon M; Sokolov, Alexei P; Saito, Tomonori

2017-08-09

Polymer membranes with the capability to process a massive volume of gas are especially attractive for practical applications of gas separation. Although much effort has been devoted to develop novel polymer membranes with increased selectivity, the overall gas-separation performance and lifetime of membrane are still negatively affected by the weak mechanical performance, low plasticization resistance and poor physical aging tolerance. Recently, elastic polymer membranes with tunable mechanical properties have been attracting significant attentions due to their tremendous potential applications. Herein, we report a series of urethane-rich PDMS-based polymer networks (U-PDMS-NW) with improved mechanical performance for gas separation. The cross-link density of U-PDMS-NWs is tailored by varying the molecular weight (M n ) of PDMS. The U-PDMS-NWs show up to 400% elongation and tunable Young's modulus (1.3-122.2 MPa), ultimate tensile strength (1.1-14.3 MPa), and toughness (0.7-24.9 MJ/m 3 ). All of the U-PDMS-NWs exhibit salient gas-separation performance with excellent thermal resistance and aging tolerance, high gas permeability (>100 Barrer), and tunable gas selectivity (up to α[P CO 2 /P N 2 ] ≈ 41 and α[P CO 2 /P CH 4 ] ≈ 16). With well-controlled mechanical properties and gas-separation performance, these U-PDMS-NW can be used as a polymer-membrane platform not only for gas separation but also for other applications such as microfluidic channels and stretchable electronic devices.

Asymmetric migration of human keratinocytes under mechanical stretch and cocultured fibroblasts in a wound repair model.

Directory of Open Access Journals (Sweden)

Dongyuan Lü

Full Text Available Keratinocyte migration during re-epithelization is crucial in wound healing under biochemical and biomechanical microenvironment. However, little is known about the underlying mechanisms whereby mechanical tension and cocultured fibroblasts or keratinocytes modulate the migration of keratinocytes or fibroblasts. Here we applied a tensile device together with a modified transwell assay to determine the lateral and transmembrane migration dynamics of human HaCaT keratinocytes or HF fibroblasts. A novel pattern of asymmetric migration was observed for keratinocytes when they were cocultured with non-contact fibroblasts, i.e., the accumulative distance of HaCaT cells was significantly higher when moving away from HF cells or migrating from down to up cross the membrane than that when moving close to HF cells or when migrating from up to down, whereas HF migration was symmetric. This asymmetric migration was mainly regulated by EGF derived from fibroblasts, but not transforming growth factor α or β1 production. Mechanical stretch subjected to fibroblasts fostered keratinocyte asymmetric migration by increasing EGF secretion, while no role of mechanical stretch was found for EGF secretion by keratinocytes. These results provided a new insight into understanding the regulating mechanisms of two- or three-dimensional migration of keratinocytes or fibroblasts along or across dermis and epidermis under biomechanical microenvironment.

Inspection Mechanism and Experimental Study of Prestressed Reverse Tension Method under PC Beam Bridge Anchorage

Science.gov (United States)

Peng, Zhang

2018-03-01

the prestress under anchorage is directly related to the structural security and performance of PC beam bridge. The reverse tension method is a kind of inspection which confirms the prestress by exerting reversed tension load on the exposed prestressing tendon of beam bridge anchoring system. The thesis elaborately expounds the inspection mechanism and mechanical effect of reverse tension method, theoretically analyzes the influential elements of inspection like tool anchorage deformation, compression of conjuncture, device glide, friction of anchorage loop mouth and elastic compression of concrete, and then presents the following formula to calculate prestress under anchorage. On the basis of model experiment, the thesis systematically studies some key issues during the reverse tension process of PC beam bridge anchorage system like the formation of stress-elongation curve, influential factors, judgment method of prestress under anchorage, variation trend and compensation scale, verifies the accuracy of mechanism analysis and demonstrates: the prestress under anchorage is less than or equal to 75% of the ultimate strength of prestressing tendon, the error of inspect result is less than 1%, which can meet with the demands of construction. The research result has provided theoretical basis and technical foundation for the promotion and application of reverse tension in bridge construction.

Behavioral Effects of Upper Respiratory Tract Illnesses: A Consideration of Possible Underlying Cognitive Mechanisms

Directory of Open Access Journals (Sweden)

Andrew P. Smith

2012-03-01

Full Text Available Previous research has shown that both experimentally induced upper respiratory tract illnesses (URTIs and naturally occurring URTIs influence mood and performance. The present study investigated possible cognitive mechanisms underlying the URTI-performance changes. Those who developed a cold (N = 47 had significantly faster, but less accurate, performance than those who remained healthy (N = 54. Illness had no effect on manipulations designed to influence encoding, response organisation (stimulus-response compatilibility or response preparation. Similarly, there was no evidence that different components of working memory were impaired. Overall, the present research confirms that URTIs can have an effect on performance efficiency. Further research is required to identify the physiological and behavioral mechanisms underlying these effects.

Exact solution for stresses/displacements in a multilayered hollow cylinder under thermo-mechanical loading

International Nuclear Information System (INIS)

Yeo, W.H.; Purbolaksono, J.; Aliabadi, M.H.; Ramesh, S.; Liew, H.L.

2017-01-01

In this study, a new analytical solution by the recursive method for evaluating stresses/displacements in multilayered hollow cylinder under thermo-mechanical loading was developed. The results for temperature distribution, displacements and stresses obtained by using the proposed solution were shown to be in good agreement with the FEM results. The proposed analytical solution was also found to produce more accurate results than those by the analytical solution reported in literature. - Highlights: • A new analytical solution for evaluating stresses in multilayered hollow cylinder under thermo-mechanical loading. • A simple computational procedure using a recursive method. • A promising technique for evaluating the operating axial and hoop stresses in pressurized composite vessels.

Light induced drift: a possible mechanism of separation of isotopes by laser excitation

International Nuclear Information System (INIS)

Biswas, D.J.; Nilaya, J.P.; Venkatramani, N.

2003-02-01

A comprehensive review of the literature on the effect of light induced drift and its exploitation in the separation of isotopes, both in atomic and molecular forms, is presented. An experimental scheme based on this effect to separate S 33 , with a natural abundance of ∼0.76%, from SF 6 has also been worked out. (author)

Recycling metals from lithium ion battery by mechanical separation and vacuum metallurgy.

Science.gov (United States)

Xiao, Jiefeng; Li, Jia; Xu, Zhengming

2017-09-15

The large-batch application of lithium ion batteries leads to the mass production of spent batteries. So the enhancement of disposal ability of spent lithium ion batteries is becoming very urgent. This study proposes an integrated process to handle bulk spent lithium manganese (LiMn 2 O 4 ) batteries to in situ recycle high value-added products without any additives. By mechanical separation, the mixed electrode materials mainly including binder, graphite and LiMn 2 O 4 are firstly obtained from spent batteries. Then, the reaction characteristics for the oxygen-free roasting of mixed electrode materials are analyzed. And the results show that mixed electrode materials can be in situ converted into manganese oxide (MnO) and lithium carbonate (Li 2 CO 3 ) at 1073K for 45min. In this process, the binder is evaporated and decomposed into gaseous products which can be collected to avoid disposal cost. Finally, 91.30% of Li resource as Li 2 CO 3 is leached from roasted powders by water and then high value-added Li 2 CO 3 crystals are further gained by evaporating the filter liquid. The filter residues are burned in air to remove the graphite and the final residues as manganous-manganic oxide (Mn 3 O 4 ) is obtained. Copyright © 2017 Elsevier B.V. All rights reserved.

Development of a dry-mechanical graphite separation process and elimination of the separated carbon for the reprocessing of spherical HTR fuel elements

International Nuclear Information System (INIS)

Kronschnabel, H.

1982-01-01

Due to the C-14 distribution the separation of the particle-free outer region of the spherical HTR fuel element with subsequent solidification of the separated carbon makes it possible to reduce by half the remaining C-14 inventory in the inner particle region to be further treated. Separation of the particle-free outer region by a newly developed sphere-peeling milling machine, conditioning the graphite into compacts and in-situ cementation into a salt-mine are the basic elements of this head-end process variation. An annual cavern volume of approx. 2000 m 3 will be needed to ultimately store the graphite of the particle-free outer region, which corresponds to a reprocessing capacity of 50 GWsub(e) installed HTR power. The brush-disintegration of the remaining inner particle region and the resulting peel-brush-preparation are capable of separating 95% of the graphite without any heavy metal losses. With the mentioned reprocessing capacity an annual cavern volume of approx. 16.500 m 3 is required. (orig.) [de

Texture segregation, surface representation and figure-ground separation.

Science.gov (United States)

Grossberg, S; Pessoa, L

1998-09-01

A widespread view is that most texture segregation can be accounted for by differences in the spatial frequency content of texture regions. Evidence from both psychophysical and physiological studies indicate, however, that beyond these early filtering stages, there are stages of 3-D boundary segmentation and surface representation that are used to segregate textures. Chromatic segregation of element-arrangement patterns--as studied by Beck and colleagues--cannot be completely explained by the filtering mechanisms previously employed to account for achromatic segregation. An element arrangement pattern is composed of two types of elements that are arranged differently in different image regions (e.g. vertically on top and diagonally on the bottom). FACADE theory mechanisms that have previously been used to explain data about 3-D vision and figure-ground separation are here used to simulate chromatic texture segregation data, including data with equiluminant elements on dark or light homogeneous backgrounds, or backgrounds composed of vertical and horizontal dark or light stripes, or horizontal notched stripes. These data include the fact that segregation of patterns composed of red and blue squares decreases with increasing luminance of the interspaces. Asymmetric segregation properties under 3-D viewing conditions with the equiluminant elements close or far are also simulated. Two key model properties are a spatial impenetrability property that inhibits boundary grouping across regions with non-collinear texture elements and a boundary-surface consistency property that uses feedback between boundary and surface representations to eliminate spurious boundary groupings and separate figures from their backgrounds.

Mechanical failure of zigzag graphene nanoribbons under tensile strain induced by edge reconstruction

KAUST Repository

Cheng, Yingchun

2012-10-01

The structural and mechanical properties of graphene nanoribbons (GNRs) under uniaxial tensile strain are studied by density functional theory. The ideal strength of a zigzag GNR (120 GPa) is close to that of pristine graphene. However, for a GNR with both edges reconstructed to pentagon–heptagon pairs (from hexagon–hexagon pairs) it decreases to 94 GPa and the maximum tensile strain is reduced to 15%. Our results constitute a comprehensive picture of the edge structure effect on the mechanical properties of GNRs.

Mechanical failure of zigzag graphene nanoribbons under tensile strain induced by edge reconstruction

KAUST Repository

Cheng, Yingchun; Schwingenschlö gl, Udo; Zhu, Zhiyong

2012-01-01

The structural and mechanical properties of graphene nanoribbons (GNRs) under uniaxial tensile strain are studied by density functional theory. The ideal strength of a zigzag GNR (120 GPa) is close to that of pristine graphene. However, for a GNR with both edges reconstructed to pentagon–heptagon pairs (from hexagon–hexagon pairs) it decreases to 94 GPa and the maximum tensile strain is reduced to 15%. Our results constitute a comprehensive picture of the edge structure effect on the mechanical properties of GNRs.

Capillary electrophoresis separation of neutral organic compounds, pharmaceutical drugs, proteins and peptides, enantiomers, and anions

Energy Technology Data Exchange (ETDEWEB)

Ding, Wei -Liang [Iowa State Univ., Ames, IA (United States)

1999-02-12

Addition of a novel anionic surfactant, namely lauryl polyoxyethylene sulfate, to an aqueous-acetonitrile electrolyte makes it possible to separate nonionic organic compounds by capillary electrophoresis. Separation is based on differences in the association between analytes and the surfactant. Highly hydrophobic compounds such as polyaromatic hydrocarbons are well separated by this new surfactant. Migration times of analytes can be readily changed over an unusually large range by varying the additive concentration and the proportion of acetonitrile in the electrolyte. Several examples are given, including the separation of four methylbenz[a]anthracene isomers and the separation of normal and deuterated acetophenone. The effect of adding this new surfactant to the acidic electrolyte was also investigated. Incorporation of cetyltrimethylammonium bromide in the electrolyte is shown to dynamically coat the capillary and reverse electroosmotic flow. Chiral recognition mechanism is studied using novel synthetic surfactants as chiral selectors, which are made from amino acids reacting with alkyl chloroformates. A satisfactory separation of both inorganic and organic anions is obtained using electrolyte solutions as high as 5 M sodium chloride using direct photometric detection. The effect of various salts on electrophoretic and electroosmotic mobility is further discussed. Several examples are given under high-salt conditions.

Microparticle Separation by Cyclonic Separation

Science.gov (United States)

Karback, Keegan; Leith, Alexander

2017-11-01

The ability to separate particles based on their size has wide ranging applications from the industrial to the medical. Currently, cyclonic separators are primarily used in agriculture and manufacturing to syphon out contaminates or products from an air supply. This has led us to believe that cyclonic separation has more applications than the agricultural and industrial. Using the OpenFoam computational package, we were able to determine the flow parameters of a vortex in a cyclonic separator in order to segregate dust particles to a cutoff size of tens of nanometers. To test the model, we constructed an experiment to separate a test dust of various sized particles. We filled a chamber with Arizona test dust and utilized an acoustic suspension technique to segregate particles finer than a coarse cutoff size and introduce them into the cyclonic separation apparatus where they were further separated via a vortex following our computational model. The size of the particles separated from this experiment will be used to further refine our model. Metropolitan State University of Denver, Colorado University of Denver, Dr. Randall Tagg, Dr. Richard Krantz.

Membrane Separation of Gas Mixtures under the Influence of Resonance Radiation.

Czech Academy of Sciences Publication Activity Database

Levdansky, Valerij Vladimirovič; Izák, Pavel

2017-01-01

Roč. 173, FEB (2017), s. 93-98 ISSN 1383-5866 R&D Projects: GA ČR GA14-12695S Institutional support: RVO:67985858 Keywords : membranes * gas mixture * separation Subject RIV: CI - Industrial Chemistry, Chemical Engineering OBOR OECD: Chemical process engineering Impact factor: 3.359, year: 2016

[Baseflow separation methods in hydrological process research: a review].

Science.gov (United States)

Xu, Lei-Lei; Liu, Jing-Lin; Jin, Chang-Jie; Wang, An-Zhi; Guan, De-Xin; Wu, Jia-Bing; Yuan, Feng-Hui

2011-11-01

Baseflow separation research is regarded as one of the most important and difficult issues in hydrology and ecohydrology, but lacked of unified standards in the concepts and methods. This paper introduced the theories of baseflow separation based on the definitions of baseflow components, and analyzed the development course of different baseflow separation methods. Among the methods developed, graph separation method is simple and applicable but arbitrary, balance method accords with hydrological mechanism but is difficult in application, whereas time series separation method and isotopic method can overcome the subjective and arbitrary defects caused by graph separation method, and thus can obtain the baseflow procedure quickly and efficiently. In recent years, hydrological modeling, digital filtering, and isotopic method are the main methods used for baseflow separation.

New developments on the neurobiological and pharmaco-genetic mechanisms underlying internet and videogame addiction.

Science.gov (United States)

Weinstein, Aviv; Lejoyeux, Michel

2015-03-01

There is emerging evidence that the psychobiological mechanisms underlying behavioral addictions such as internet and videogame addiction resemble those of addiction for substances of abuse. Review of brain imaging, treatment and genetic studies on videogame and internet addiction. Literature search of published articles between 2009 and 2013 in Pubmed using "internet addiction" and "videogame addiction" as the search word. Twenty-nine studies have been selected and evaluated under the criteria of brain imaging, treatment, and genetics. Brain imaging studies of the resting state have shown that long-term internet game playing affected brain regions responsible for reward, impulse control and sensory-motor coordination. Brain activation studies have shown that videogame playing involved changes in reward and loss of control and that gaming pictures have activated regions similarly to those activated by cue-exposure to drugs. Structural studies have shown alterations in the volume of the ventral striatum possible as result of changes in reward. Furthermore, videogame playing was associated with dopamine release similar in magnitude to those of drugs of abuse and that there were faulty inhibitory control and reward mechanisms videogame addicted individuals. Finally, treatment studies using fMRI have shown reduction in craving for videogames and reduced associated brain activity. Videogame playing may be supported by similar neural mechanisms underlying drug abuse. Similar to drug and alcohol abuse, internet addiction results in sub-sensitivity of dopamine reward mechanisms. Given the fact that this research is in its early stage it is premature to conclude that internet addiction is equivalent to substance addictions. © American Academy of Addiction Psychiatry.

Qualification of a novel deepwater gas / liquid separator

Energy Technology Data Exchange (ETDEWEB)

Abrand, Stephanie

2010-07-01

The implementation of subsea boosting and processing systems is becoming a common development scheme for the development of deep and ultra-deep water fields. Those subsea processing systems shall address the mechanical and functional constraints that are imposed by the deepwater installation and operation along with the obvious reliability requirements. Saipem has developed a deepwater gas separation and liquid boosting system that encompasses a good flexibility in handling a wide range of steady and unsteady multiphase input streams and a relatively simple mechanical arrangement. The system is composed of an array of vertical pipes that contributes in providing the required separation and liquid hold up volumes. The reduced diameter and wall thickness of the vertical pipes, as compared with the equivalent single separation vessel, is particularly suited in deep and ultra-deep water applications and/or high pressure services. Furthermore, the system relies on the gravity separation whose efficiency is ensured by its ability to accommodate large variety of input flowrate and un-steady regimes. In the continuous effort of providing reliable and proven process solutions to the market, Saipem has undertaken a qualification program focused to characterise and demonstrate the system versatility and separation performances, that will involve model testing in multiphase conditions. (Author)

Neural mechanisms underlying melodic perception and memory for pitch.

Science.gov (United States)

Zatorre, R J; Evans, A C; Meyer, E

1994-04-01

The neural correlates of music perception were studied by measuring cerebral blood flow (CBF) changes with positron emission tomography (PET). Twelve volunteers were scanned using the bolus water method under four separate conditions: (1) listening to a sequence of noise bursts, (2) listening to unfamiliar tonal melodies, (3) comparing the pitch of the first two notes of the same set of melodies, and (4) comparing the pitch of the first and last notes of the melodies. The latter two conditions were designed to investigate short-term pitch retention under low or high memory load, respectively. Subtraction of the obtained PET images, superimposed on matched MRI scans, provides anatomical localization of CBF changes associated with specific cognitive functions. Listening to melodies, relative to acoustically matched noise sequences, resulted in CBF increases in the right superior temporal and right occipital cortices. Pitch judgments of the first two notes of each melody, relative to passive listening to the same stimuli, resulted in right frontal-lobe activation. Analysis of the high memory load condition relative to passive listening revealed the participation of a number of cortical and subcortical regions, notably in the right frontal and right temporal lobes, as well as in parietal and insular cortex. Both pitch judgment conditions also revealed CBF decreases within the left primary auditory cortex. We conclude that specialized neural systems in the right superior temporal cortex participate in perceptual analysis of melodies; pitch comparisons are effected via a neural network that includes right prefrontal cortex, but active retention of pitch involves the interaction of right temporal and frontal cortices.

Ablation characteristics and reaction mechanism of insulation materials under slag deposition condition

Science.gov (United States)

Guan, Yiwen; Li, Jiang; Liu, Yang

2017-07-01

Current understanding of the physical and chemical processes involved in the ablation of insulation materials by highly aluminized solid propellants is limited. The study on the heat transfer and ablation principle of ethylene propylene diene monomer (EPDM) materials under slag deposition condition is essential for future design or modification of large solid rocket motors (SRMs) for launch application. In this paper, the alumina liquid flow pattern and the deposition principle in full-scale SRM engines are discussed. The interaction mechanism between the alumina droplets and the wall are analyzed. Then, an experimental method was developed to simulate the insulation material ablation under slag deposition condition. Experimental study was conducted based on a laboratory-scale device. Meanwhile, from the analysis of the cross-sectional morphology and chemical composition of the charring layer after ablation, the reaction mechanism of the charring layer under deposition condition was discussed, and the main reaction equation was derived. The numerical simulation and experimental results show the following. (i) The alumina droplet flow in the deposition section of the laboratory-scale device is similar to that of a full-scale SRM. (ii) The charring layer of the EPDM insulator displays a porous tight/loose structure under high-temperature slag deposition condition. (iii) A seven-step carbothermal reduction in the alumina is derived and established under high-pressure and high-temperature environment in the SRM combustion chamber. (iv) The analysis using thermodynamic software indicates that the reaction of the alumina and charring layer initially forms Al4C3 during the operation. Then, Al element and Al2OC compound are subsequently produced with the reduction in the release of gas CO as well with continuous environmental heating.

From Sound to Significance: Exploring the Mechanisms Underlying Emotional Reactions to Music.

Science.gov (United States)

Juslin, Patrik N; Barradas, Gonçalo; Eerola, Tuomas

2015-01-01

A common approach to studying emotional reactions to music is to attempt to obtain direct links between musical surface features such as tempo and a listener's responses. However, such an analysis ultimately fails to explain why emotions are aroused in the listener. In this article we explore an alternative approach, which aims to account for musical emotions in terms of a set of psychological mechanisms that are activated by different types of information in a musical event. This approach was tested in 4 experiments that manipulated 4 mechanisms (brain stem reflex, contagion, episodic memory, musical expectancy) by selecting existing musical pieces that featured information relevant for each mechanism. The excerpts were played to 60 listeners, who were asked to rate their felt emotions on 15 scales. Skin conductance levels and facial expressions were measured, and listeners reported subjective impressions of relevance to specific mechanisms. Results indicated that the target mechanism conditions evoked emotions largely as predicted by a multimechanism framework and that mostly similar effects occurred across the experiments that included different pieces of music. We conclude that a satisfactory account of musical emotions requires consideration of how musical features and responses are mediated by a range of underlying mechanisms.

Separation kinetics of an oil-in-water emulsion under enhanced gravity

NARCIS (Netherlands)

Krebs, T.; Schroën, C.G.P.H.; Boom, R.M.

2012-01-01

The breakup of crude oil emulsions to produce clean oil and water phases is an important task in crude oil processing. We have investigated the demulsification kinetics of a model oil-in-water emulsion in a centrifugal field to mimic the forces acting on emulsion droplets in oil/water separators

Molecular Mechanisms Underlying the Epileptogenesis and Seizure Progression in Tuberous Sclerosis Complex 1 Deficient Mouse Models

Science.gov (United States)

2016-10-01

dysregulation in epileptogenesis in the developing brain? 2) What are the molecular mechanisms downstream of mTOR hyperactivation that trigger epileptogenesis...underlying epilepsy. Hopefully, a knowledge of these mechanisms will aid in a rational development of therapies. KEYWORDS Tuberous Sclerosis, Epilepsy

Optically transparent, mechanically durable, nanostructured superhydrophobic surfaces enabled by spinodally phase-separated glass thin films.

Science.gov (United States)

Aytug, Tolga; Simpson, John T; Lupini, Andrew R; Trejo, Rosa M; Jellison, Gerald E; Ivanov, Ilia N; Pennycook, Stephen J; Hillesheim, Daniel A; Winter, Kyle O; Christen, David K; Hunter, Scott R; Haynes, J Allen

2013-08-09

We describe the formation and properties of atomically bonded, optical quality, nanostructured thin glass film coatings on glass plates, utilizing phase separation by spinodal decomposition in a sodium borosilicate glass system. Following deposition via magnetron sputtering, thermal processing and differential etching, these coatings are structurally superhydrophilic (i.e., display anti-fogging functionality) and demonstrate robust mechanical properties and superior abrasion resistance. After appropriate chemical surface modification, the surfaces display a stable, non-wetting Cassie-Baxter state and exhibit exceptional superhydrophobic performance, with water droplet contact angles as large as 172°. As an added benefit, in both superhydrophobic and superhydrophilic states these nanostructured surfaces can block ultraviolet radiation and can be engineered to be anti-reflective with broadband and omnidirectional transparency. Thus, the present approach could be tailored toward distinct coatings for numerous markets, such as residential windows, windshields, specialty optics, goggles, electronic and photovoltaic cover glasses, and optical components used throughout the US military.

Optically transparent, mechanically durable, nanostructured superhydrophobic surfaces enabled by spinodally phase-separated glass thin films

Science.gov (United States)

Aytug, Tolga; Simpson, John T.; Lupini, Andrew R.; Trejo, Rosa M.; Jellison, Gerald E.; Ivanov, Ilia N.; Pennycook, Stephen J.; Hillesheim, Daniel A.; Winter, Kyle O.; Christen, David K.; Hunter, Scott R.; Haynes, J. Allen

2013-08-01

We describe the formation and properties of atomically bonded, optical quality, nanostructured thin glass film coatings on glass plates, utilizing phase separation by spinodal decomposition in a sodium borosilicate glass system. Following deposition via magnetron sputtering, thermal processing and differential etching, these coatings are structurally superhydrophilic (i.e., display anti-fogging functionality) and demonstrate robust mechanical properties and superior abrasion resistance. After appropriate chemical surface modification, the surfaces display a stable, non-wetting Cassie-Baxter state and exhibit exceptional superhydrophobic performance, with water droplet contact angles as large as 172°. As an added benefit, in both superhydrophobic and superhydrophilic states these nanostructured surfaces can block ultraviolet radiation and can be engineered to be anti-reflective with broadband and omnidirectional transparency. Thus, the present approach could be tailored toward distinct coatings for numerous markets, such as residential windows, windshields, specialty optics, goggles, electronic and photovoltaic cover glasses, and optical components used throughout the US military.

Optically transparent, mechanically durable, nanostructured superhydrophobic surfaces enabled by spinodally phase-separated glass thin films

International Nuclear Information System (INIS)

Aytug, Tolga; Simpson, John T; Lupini, Andrew R; Trejo, Rosa M; Jellison, Gerald E; Ivanov, Ilia N; Pennycook, Stephen J; Hillesheim, Daniel A; Winter, Kyle O; Christen, David K; Hunter, Scott R; Allen Haynes, J

2013-01-01

We describe the formation and properties of atomically bonded, optical quality, nanostructured thin glass film coatings on glass plates, utilizing phase separation by spinodal decomposition in a sodium borosilicate glass system. Following deposition via magnetron sputtering, thermal processing and differential etching, these coatings are structurally superhydrophilic (i.e., display anti-fogging functionality) and demonstrate robust mechanical properties and superior abrasion resistance. After appropriate chemical surface modification, the surfaces display a stable, non-wetting Cassie–Baxter state and exhibit exceptional superhydrophobic performance, with water droplet contact angles as large as 172°. As an added benefit, in both superhydrophobic and superhydrophilic states these nanostructured surfaces can block ultraviolet radiation and can be engineered to be anti-reflective with broadband and omnidirectional transparency. Thus, the present approach could be tailored toward distinct coatings for numerous markets, such as residential windows, windshields, specialty optics, goggles, electronic and photovoltaic cover glasses, and optical components used throughout the US military. (paper)

Lifetime of Mechanical Equipment

Energy Technology Data Exchange (ETDEWEB)

Leland, K.

1999-07-01

The gas plant at Kaarstoe was built as part of the Statpipe gas transport system and went on stream in 1985. In 1993 another line was routed from the Sleipner field to carry condensate, and the plant was extended accordingly. Today heavy additional supply- and export lines are under construction, and the plant is extended more than ever. The main role of the factory is to separate the raw gas into commercial products and to pump or ship it to the markets. The site covers a large number of well-known mechanical equipment. This presentation deals with piping, mechanical and structural disciplines. The lifetime of mechanical equipment is often difficult to predict as it depends on many factors, and the subject is complex. Mechanical equipment has been kept in-house, which provides detailed knowledge of the stages from a new to a 14 years old plant. The production regularity has always been very high, as required. The standard of the equipment is well kept, support systems are efficient, and human improvisation is extremely valuable.

Separation of polyethylene terephthalate from municipal waste plastics by froth flotation for recycling industry

International Nuclear Information System (INIS)

Wang, Chong-Qing; Wang, Hui; Liu, You-Nian

2015-01-01

Highlights: • Factors of NaOH treatment were studied by orthogonal and single factor experiments. • Mechanism of alkaline treatment for facilitating flotation was manifested. • Flotation separation of PET was achieved with high purity and efficiency. • A flow sheet of purification PET from MWP was designed. - Abstract: Recycling is an effective way to manage plastic wastes and receives considerable attention. Since plastic mixtures are difficult to recycle because of their intrinsic characteristics, separation of mixed plastics is the key problem for recycling. Separation of polyethylene terephthalate (PET) from municipal waste plastics (MWP) by froth flotation combined with alkaline pretreatment was investigated for recycling industry. The effect of process variables was estimated by L 9 (3 4 ) orthogonal array of experiments and single factor experiments. The optimum conditions of alkaline pretreatment are 10 wt% sodium hydroxide, 20 min and 70 °C. After alkaline pretreatment under optimum conditions, flotation separation PET from acrylonitrile–butadiene–styrene, polystyrene, polycarbonate or polyvinyl chloride was achieved with high purity and efficiency. The purity of PET is up to 98.46% and the recovery is above 92.47%. A flow sheet of separation PET from MWP by a combination of froth flotation and sink float separation was designed. This study facilitates industrial application of plastics flotation and provides technical insights into recycling of waste plastics

Separation of polyethylene terephthalate from municipal waste plastics by froth flotation for recycling industry

Energy Technology Data Exchange (ETDEWEB)

Wang, Chong-Qing; Wang, Hui, E-mail: huiwang1968@163.com; Liu, You-Nian

2015-01-15

Highlights: • Factors of NaOH treatment were studied by orthogonal and single factor experiments. • Mechanism of alkaline treatment for facilitating flotation was manifested. • Flotation separation of PET was achieved with high purity and efficiency. • A flow sheet of purification PET from MWP was designed. - Abstract: Recycling is an effective way to manage plastic wastes and receives considerable attention. Since plastic mixtures are difficult to recycle because of their intrinsic characteristics, separation of mixed plastics is the key problem for recycling. Separation of polyethylene terephthalate (PET) from municipal waste plastics (MWP) by froth flotation combined with alkaline pretreatment was investigated for recycling industry. The effect of process variables was estimated by L{sub 9} (3{sup 4}) orthogonal array of experiments and single factor experiments. The optimum conditions of alkaline pretreatment are 10 wt% sodium hydroxide, 20 min and 70 °C. After alkaline pretreatment under optimum conditions, flotation separation PET from acrylonitrile–butadiene–styrene, polystyrene, polycarbonate or polyvinyl chloride was achieved with high purity and efficiency. The purity of PET is up to 98.46% and the recovery is above 92.47%. A flow sheet of separation PET from MWP by a combination of froth flotation and sink float separation was designed. This study facilitates industrial application of plastics flotation and provides technical insights into recycling of waste plastics.

Hydrogen isotope separation by cryogenic distillation method

International Nuclear Information System (INIS)

Hayakawa, Nobuo; Mitsui, Jin

1987-01-01

Hydrogen isotope separation in fusion fuel cycle and tritium recovery from heavy water reactor are very important, and therefore the early establishment of these separation techniques are desired. The cryogenic distillation method in particular is promising for the separation of hydrogen isotope and the recovery of high concentrated tritium. The studies of hydrogen isotope separation by cryogenic distillation method have been carried out by using the experimental apparatus made for the first time in Japan. The separation of three components (H 2 -HD-D 2 ) under total reflux conditions was got by using the packing tower of 500 mm height. It was confirmed that the Height Equivalent Theoretical Plate (HETP) was 20 - 30 mm for the vapor's line velocity of 20 - 80 mm/s. (author)

A one-stage, high-load capacity separation actuator using anti-friction rollers and redundant shape memory alloy wires.

Science.gov (United States)

Xiaojun, Yan; Dawei, Huang; Xiaoyong, Zhang; Ying, Liu; Qiaolong, Yang

2015-12-01

This paper proposes a SMA (shape memory alloy) wire-based separation actuator with high-load capacity and simple structure. The novel actuator is based on a one-stage locking mechanism, which means that the separation is directly driven by the SMA wire. To release a large preload, a group of anti-friction rollers are adopted to reduce the force for triggering. In addition, two SMA wires are used redundantly to ensure a high reliability. After separation, the actuator can be reset automatically without any auxiliary tool or manual operation. Three prototypes of the separation actuator are fabricated and tested. According to the performance test results, the actuator can release a maximum preload of 40 kN. The separation time tends to decrease as the operation current increases and it can be as short as 0.5 s under a 7.5 A (the voltage is 5.8 V) current. Lifetime test indicates that the actuator has a lifetime of more than 50 cycles. The environmental tests demonstrate that the actuator can endure the typical thermal and vibration environment tests without unexpected separation or structure damage, and separate normally after these environment tests.

Mechanical stress analysis for a fuel rod under normal operating conditions

International Nuclear Information System (INIS)

Pino, Eddy S.; Giovedi, Claudia; Serra, Andre da Silva; Abe, Alfredo Y.

2013-01-01

Nuclear reactor fuel elements consist mainly in a system of a nuclear fuel encapsulated by a cladding material subject to high fluxes of energetic neutrons, high operating temperatures, pressure systems, thermal gradients, heat fluxes and with chemical compatibility with the reactor coolant. The design of a nuclear reactor requires, among a set of activities, the evaluation of the structural integrity of the fuel rod submitted to different loads acting on the fuel rod and the specific properties (dimensions and mechanical and thermal properties) of the cladding material and coolant, including thermal and pressure gradients produced inside the rod due to the fuel burnup. In this work were evaluated the structural mechanical stresses of a fuel rod using stainless steel as cladding material and UO 2 with a low degree of enrichment as fuel pellet on a PWR (pressurized water reactor) under normal operating conditions. In this sense, tangential, radial and axial stress on internal and external cladding surfaces considering the orientations of 0 deg, 90 deg and 180 deg were considered. The obtained values were compared with the limit values for stress to the studied material. From the obtained results, it was possible to conclude that, under the expected normal reactor operation conditions, the integrity of the fuel rod can be maintained. (author)

Uncovering the underlying physical mechanisms of biological systems via quantification of landscape and flux

International Nuclear Information System (INIS)

Xu Li; Chu Xiakun; Yan Zhiqiang; Zheng Xiliang; Zhang Kun; Zhang Feng; Yan Han; Wu Wei; Wang Jin

2016-01-01

In this review, we explore the physical mechanisms of biological processes such as protein folding and recognition, ligand binding, and systems biology, including cell cycle, stem cell, cancer, evolution, ecology, and neural networks. Our approach is based on the landscape and flux theory for nonequilibrium dynamical systems. This theory provides a unifying principle and foundation for investigating the underlying mechanisms and physical quantification of biological systems. (topical review)

Polydimethylsiloxane-Based Superhydrophobic Surfaces on Steel Substrate: Fabrication, Reversibly Extreme Wettability and Oil-Water Separation.

Science.gov (United States)

Su, Xiaojing; Li, Hongqiang; Lai, Xuejun; Zhang, Lin; Liang, Tao; Feng, Yuchun; Zeng, Xingrong

2017-01-25

Functional surfaces for reversibly switchable wettability and oil-water separation have attracted much interest with pushing forward an immense influence on fundamental research and industrial application in recent years. This article proposed a facile method to fabricate superhydrophobic surfaces on steel substrates via electroless replacement deposition of copper sulfate (CuSO 4 ) and UV curing of vinyl-terminated polydimethylsiloxane (PDMS). PDMS-based superhydrophobic surfaces exhibited water contact angle (WCA) close to 160° and water sliding angle (WSA) lower than 5°, preserving outstanding chemical stability that maintained superhydrophobicity immersing in different aqueous solutions with pH values from 1 to 13 for 12 h. Interestingly, the superhydrophobic surface could dramatically switch to the superhydrophilic state under UV irradiation and then gradually recover to the highly hydrophobic state with WCA at 140° after dark storage. The underlying mechanism was also investigated by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. Additionally, the PDMS-based steel mesh possessed high separation efficiency and excellent reusability in oil-water separation. Our studies provide a simple, fast, and economical fabrication method for wettability-transformable superhydrophobic surfaces and have the potential applications in microfluidics, the biomedical field, and oil spill cleanup.

Age differences in the underlying mechanisms of stereotype threat effects.

Science.gov (United States)

Popham, Lauren E; Hess, Thomas M

2015-03-01

The goals of the present study were to (a) examine whether age differences exist in the mechanisms underlying stereotype threat effects on cognitive performance and (b) examine whether emotion regulation abilities may buffer against threat effects on performance. Older and younger adults were exposed to positive or negative age-relevant stereotypes, allowing us to examine the impact of threat on regulatory focus and working memory. Self-reported emotion regulation measures were completed prior to the session. Older adults' performance under threat suggested a prevention-focused approach to the task, indexed by increased accuracy and reduced speed. The same pattern was observed in younger adults, but the effects were not as strong. Age differences emerged when examining the availability of working memory resources under threat, with young adults showing decrements, whereas older adults did not. Emotion regulation abilities moderated threat effects in young adults but not in older adults. The results provide support for the notion that stereotype threat may lead to underperformance through somewhat different pathways in older and younger adults. Future research should further examine whether the underlying reason for this age difference is rooted in age-related improvements in emotion regulation. © The Author 2013. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Transformational Leadership and Organizational Citizenship Behavior: A Meta-Analytic Test of Underlying Mechanisms.

Science.gov (United States)

Nohe, Christoph; Hertel, Guido

2017-01-01

Based on social exchange theory, we examined and contrasted attitudinal mediators (affective organizational commitment, job satisfaction) and relational mediators (trust in leader, leader-member exchange; LMX) of the positive relationship between transformational leadership and organizational citizenship behavior (OCB). Hypotheses were tested using meta-analytic path models with correlations from published meta-analyses (761 samples with 227,419 individuals overall). When testing single-mediator models, results supported our expectations that each of the mediators explained the relationship between transformational leadership and OCB. When testing a multi-mediator model, LMX was the strongest mediator. When testing a model with a latent attitudinal mechanism and a latent relational mechanism, the relational mechanism was the stronger mediator of the relationship between transformational leadership and OCB. Our findings help to better understand the underlying mechanisms of the relationship between transformational leadership and OCB.

Mechanisms underlying epithelium-dependent relaxation in rat bronchioles

DEFF Research Database (Denmark)

Kroigaard, Christel; Dalsgaard, Thomas; Simonsen, Ulf

2010-01-01

This study investigated the mechanisms underlying epithelium-derived hyperpolarizing factor (EpDHF)-type relaxation in rat bronchioles. Immunohistochemistry was performed, and rat bronchioles and pulmonary arteries were mounted in microvascular myographs for functional studies. An opener of small...... (SK(Ca)) and intermediate (IK(Ca))-conductance calcium-activated potassium channels, NS309 (6,7-dichloro-1H-indole-2,3-dione 3-oxime) was used to induce EpDHF-type relaxation. IK(Ca) and SK(Ca)3 positive immunoreactions were observed mainly in the epithelium and endothelium of bronchioles and arteries......, respectively. In 5-hydroxytryptamine (1 microM)-contracted bronchioles (828 +/- 20 microm, n = 84) and U46619 (0.03 microM)-contracted arteries (720 +/- 24 microm, n = 68), NS309 (0.001-10 microM) induced concentration-dependent relaxations that were reduced by epithelium/endothelium removal and by blocking IK...

NEMD study for supercavitation mechanism with underwater object

Energy Technology Data Exchange (ETDEWEB)

Gong Bozhi [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China); Zhang Bingjian [Department of Chemistry, Zhejiang University, Hangzhou, Zhejiang 310027 (China)], E-mail: zbj@mail.ha.zj.cn; Zhang Hui [Department of Chemistry, Ohio State University, Columbus, OH 43210 (United States)

2008-11-24

An open system model was introduced for Non-Equilibrium Molecular Dynamics (NEMD) simulation for studying flow phenomenon surrounding different underwater object. Cavitation number {sigma} criterion was proved to be applicable in predicting local cavitation mechanism. An interesting phenomenon was found that low {sigma} areas and actual cavities were spatially separated in molecular scale, and stable supercavitation would require a large enough low {sigma} area to sustain. Effects of cavitator shape and flow velocity were compared with macro scale flow under similar {sigma}, providing a new computational method to study the molecular scale mechanism of this phenomenon.

NEMD study for supercavitation mechanism with underwater object

International Nuclear Information System (INIS)

Gong Bozhi; Zhang Bingjian; Zhang Hui

2008-01-01

An open system model was introduced for Non-Equilibrium Molecular Dynamics (NEMD) simulation for studying flow phenomenon surrounding different underwater object. Cavitation number σ criterion was proved to be applicable in predicting local cavitation mechanism. An interesting phenomenon was found that low σ areas and actual cavities were spatially separated in molecular scale, and stable supercavitation would require a large enough low σ area to sustain. Effects of cavitator shape and flow velocity were compared with macro scale flow under similar σ, providing a new computational method to study the molecular scale mechanism of this phenomenon

Reduced Graphene Oxide-Gold Nanoparticle Nanoframework as a Highly Selective Separation Material for Aflatoxins.

Science.gov (United States)

Guo, Wenbo; Wu, Lidong; Fan, Kai; Nie, Dongxia; He, Weijing; Yang, Junhua; Zhao, Zhihui; Han, Zheng

2017-11-03

Graphene-based materials have been studied in many applications, owing to the excellent electrical, mechanical, and thermal properties of graphene. In the current study, an environmentally friendly approach to the preparation of a reduced graphene oxide-gold nanoparticle (rGO-AuNP) nanocomposite was developed by using L-cysteine and vitamin C as reductants under mild reaction conditions. The rGO-AuNP material showed a highly selective separation ability for 6 naturally occurring aflatoxins, which are easily adsorbed onto traditional graphene materials but are difficult to be desorbed. The specificity of the nanocomposite was evaluated in the separation of 6 aflatoxin congeners (aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, aflatoxin M1 and aflatoxin M2) from 23 other biotoxins (including, ochratoxin A, citrinin, and deoxynivalenol). The results indicated that this material was specific for separating aflatoxin congeners. The synthesized material was further validated by determining the recovery (77.6-105.0%), sensitivity (limit of detection in the range of 0.05-0.21 μg kg -1 ), and precision (1.5-11.8%), and was then successfully applied to the separation of aflatoxins from real-world maize, wheat and rice samples.

Imitation in Newborn Infants: Exploring the Range of Gestures Imitated and the Underlying Mechanisms.

Science.gov (United States)

Meltzoff, Andrew N.; Moore, M. Keith

1989-01-01

Evaluated psychological mechanisms underlying imitation of facial actions in 40 newborn infants. Results showed imitation of head movement and a tongue-protrusion gesture. Subjects imitated from memory after displays had stopped. (RJC)

Can components in distortion-product otoacoustic emissions be separated?

DEFF Research Database (Denmark)

Christensen, Anders Tornvig; W. Purcell, David; Christensen, Flemming

2012-01-01

Otoacoustic emissions are signals emitted from the cochlea, either spontaneously or evoked by stimuli. Measured with an acoustic probe sealed in the ear-canal, they reveal information about a part of the mechanism of hearing that is otherwise inaccessible. Outer hair cells in the cochlea work...... to improve hearing sensitivity by means of nonlinear amplification, which produces distortion. In the measurement of otoacoustic emissions, two tones can be delivered to the cochlea to invoke this nonlinearity and elicit the distortion-product otoacoustic emission (DPOAE). DPOAEs arise mainly from two...... spatially separated generation mechanisms, thus making interpretation of DPOAE measurements complicated. In this study, we test whether or not source separation by group delays is equivalent to separation by time delays – either result is equally interesting to understand given the complexity of the cochlea...

Deformation mechanisms in Ti/TiN multilayer under compressive loading

International Nuclear Information System (INIS)

Yang, Wei; Ayoub, Georges; Salehinia, Iman; Mansoor, Bilal; Zbib, Hussein

2017-01-01

The promising mechanical, physical and chemical properties of nano-scale metal/ceramic multilayers (MCMs) are of high interest for extreme environment applications. Understanding the plastic deformation mechanisms and the variables affecting those properties is therefore essential. The interface characteristics and the plastic deformation mechanisms under compressive loading in a Ti/TiN multilayer with a semi-coherent interface are numerically investigated. The interface structure of the Ti/TiN interface and the interface misfit dislocation were characterized using molecular dynamic simulations combined with atomically informed Frank-Bilby method. Three possible atomic stacking interface structures are identified according to the crystallographic analysis of the interface. Upon relaxation, large interface areas are occupied with the energetically stable configuration. Furthermore, the higher energy stacking are transformed into misfit dislocations or dislocation nodes. The molecular dynamic compressive stress strain response of the Ti/TiN multilayers exhibited three distinctive peaks. The first peak was generated by the dislocation dissociation of perfect dislocation into pairs of partials dislocation around extended nodes region at the interface. Upon further compression the second peak, identified as the first yielding, resulted from the activation of pyramidal slip planes in the Ti layer. Finally, a third peak identified as the second yielding, occurred when dislocation nucleated/transmitted in/into the TiN layer.

Separate collection of plastic waste, better than technical sorting from municipal solid waste?

Science.gov (United States)

Feil, Alexander; Pretz, Thomas; Jansen, Michael; Thoden van Velzen, Eggo U

2017-02-01

The politically preferred solution to fulfil legal recycling demands is often implementing separate collection systems. However, experience shows their limitations, particularly in urban centres with a high population density. In response to the European Union landfill directive, mechanical biological waste treatment plants have been installed all over Europe. This technology makes it possible to retrieve plastic waste from municipal solid waste. Operators of mechanical biological waste treatment plants, both in Germany and the Netherlands, have started to change their mechanical separation processes to additionally produce plastic pre-concentrates. Results from mechanical biological waste treatment and separate collection of post-consumer packaging waste will be presented and compared. They prove that both the yield and the quality of plastic waste provided as feedstock for the production of secondary plastic raw material are largely comparable. An economic assessment shows which conditions for a technical sorting plant are economically attractive in comparison to separate collection systems. It is, however, unlikely that plastic recycling will ever reach cost neutrality.

Protein unfolding versus β-sheet separation in spider silk nanocrystals

International Nuclear Information System (INIS)

Alam, Parvez

2014-01-01

In this communication a mechanism for spider silk strain hardening is proposed. Shear failure of β-sheet nanocrystals is the first failure mode that gives rise to the creation of smaller nanocrystals, which are of higher strength and stiffness. β-sheet unfolding requires more energy than nanocrystal separation in a shear mode of failure. As a result, unfolding occurs after the nanocrystals separate in shear. β-sheet unfolding yields a secondary strain hardening effect once the β-sheet conformation is geometrically stable and acts like a unidirectional fibre in a fibre reinforced composite. The mechanism suggested herein is based on molecular dynamics calculations of residual inter-β-sheet separation strengths against residual intra-β-sheet unfolding strengths. (paper)

Ion separation from dilute electrolyte solutions by nanofiltration

International Nuclear Information System (INIS)

Garcia, Corazon M.

2000-03-01

Nanofiltration (NF) is a pressure-driven process which is considered potential for the separation of ionic species selectively from solutions containing mixture of electrolyte solutes. The lower operating pressure requirement of NF than reverse osmosis (RO) makes the earlier potentially economical. In the separation of ions, many authors believed that there are membranes with characteristic fixed surface charge and that the mechanism of separation of ions is by the differences in valences of the ions. In this study, experiments involving dilute single-solute and multiple-solute electrolyte solutions were performed using three different NF membranes. Permeate fluxes and ion rejections of the different species of ions in samples of permeate solutions were measured at varied conditions. The mechanism of separation in NF was determined based on the analysis of the trends and behavior of ion rejection relative to the solution temperature, pressure, type of solute, feed concentration and feed solution pH. The results of the experiments show that there is no evidence of the presence of fixed surface charge on the NF membranes. Ion separation was made possible by the combination of sieve effect and ion-hydration effect. Ions having higher hydration numbers showed higher ion rejection than those having lower hydration numbers. A method to determine the effective membrane pore size of NF membranes using hydrodynamic model was proposed. The proposed method is based on the assumptions that the membrane is neutral and that the separation is based on sieving effect. (Author)

Influence of Hard Segments on the Thermal, Phase-Separated Morphology, Mechanical, and Biological Properties of Polycarbonate Urethanes

Directory of Open Access Journals (Sweden)

Rong Zhu

2017-03-01

Full Text Available Abstract: In this study, we have fabricated a series of polycarbonate polyurethanes using a two-step bulk reaction by the melting pre-polymer solution-casting method in order to synthesize biomedical polyurethane elastomers with good mechanical behavior and biostability. The polyurethanes were prepared using dibutyltin dilaurate as the catalyst, poly(1,6-hexanediolcarbonate microdiols (PCDL as the soft segment, and the chain extender 1,4-butanediol (BDO and aliphatic 1,6-hexamethylene diisocyanate (HDI as the hard segments. The chemical structures and physical properties of the obtained films were characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy, gel permeation chromatography (GPC, differential scanning calorimeter (DSC, and mechanical property tests. The surface properties and degrees of microphase separation were further analyzed by water droplet contact angle measurements (CA and atomic force microscopy (AFM. The materials exhibited a moderate toxic effect on the tetrazolium (MTT assay and good hemocompatibility through hemolytic tests, indicating a good biocompatibility of the fabricated membranes. The materials could be considered as potential and beneficial suitable materials for tissue engineering, especially in the fields of artificial blood-contacting implants or other biomedical applications.

Plate Tearing Under Mixed Mode Loading

DEFF Research Database (Denmark)

Andersen, Rasmus Grau; Nielsen, Kim Lau; Felter, Christian Lotz

2016-01-01

the mesh cannot accurately capture the localization process that precedes ductile failure. To fertilize accurate predictions of such sheet tearing, the energy dissipated during localization must, therefore, be accounted for in the cohesive traction-separation law. The fact is that the local thinning...... that takes place in front of an advancing crack can significantly enhance the crack growth resistanceas the energy going into thinning the sheet typically dominates the total fracture energy.This has been investigated in great details for the case of pure Mode I tearing and both the energy dissipation, peak...... stress, and shape of the cohesive traction-separation law have been laid out. In a similar fashion, the present study resolves the sequence of failure details related to steady-state sheet tearing under mixed mode loading by employing the micro-mechanics based Gurson model. But, the fracture process...

Rock mechanics. Proceedings of the 33rd U.S. symposium

International Nuclear Information System (INIS)

Tillerson, J.R.; Wawersik, W.R.

1992-01-01

After giving abstracts of the award winning papers for 1991 and the keynote lecture, papers are presented under the following headings: origin of stresses in the lithosphere; fault mechanics; rock mass monitoring; subsidence and ground motions; blasting; reservoir completion and stimulation; underground storage and sealing; design and supports; fluid and contaminant transport; numerical methods; constitutive modelling and strain localization; nonlinear dynamic systems; geostatistics and reliability; fracture mechanics; physical rock properties; experimental methods; geotechnical design methodology - workshop; and induced seismicity - workshop. Six papers have been abstracted separately

A study of liberation and separation process of metals from printed circuit boards (PCBs) scrap

International Nuclear Information System (INIS)

Noorliyana, H.A.; Zaheruddin, K.; Mohd Fazlul Bari; M. Sri Asliza; Nurhidayah, A.Z.; Kamarudin, H.

2009-01-01

Since the metallic elements are covered with or encapsulated by various plastic or ceramic materials on printed circuit boards, a mechanical pre-treatment process allowing their liberation and separation is first needed in order to facilitate their efficient extraction with hydrometallurgy route. Even though many studies have been performed on the mechanical pre-treatment processing for the liberation and separation of the metallic components of printed circuit boards scrap, further studies are required to pave the way for efficient recycling of waste printed circuit boards through a combination of mechanical pre-treatment and hydrometallurgical technology. In this work, a fundamental study has been carried out on the mechanical pre-treatment that is necessary to recover metallic concentrates from printed circuit boards scraps. The most important problem is to separate or release particles from the associated gangue minerals at the possible liberation particle size. The distribution of metallic elements has been also investigated in relation to the particle size of the milled printed circuit boards. The samples of printed circuit boards were separated into the magnetic and non-magnetic fractions by Rare-earth Roll Magnetic separator. Thereafter, the magnetic and non-magnetic fractions were separated to heavy fraction (metallic elements) and light fraction (plastic) by Mozley Laboratory Table Separator. The recovery ratios and the evaluation of the metallic concentrates recovered by each separation process were also investigated. This study is expected to provide useful data for the efficient mechanical separation of metallic components from printed circuit boards scraps. (author)

Microcracking in composite laminates under thermal and mechanical loading. Thesis

Science.gov (United States)

Maddocks, Jason R.

1995-01-01

Composites used in space structures are exposed to both extremes in temperature and applied mechanical loads. Cracks in the matrix form, changing the laminate thermoelastic properties. The goal of the present investigation is to develop a predictive methodology to quantify microcracking in general composite laminates under both thermal and mechanical loading. This objective is successfully met through a combination of analytical modeling and experimental investigation. In the analysis, the stress and displacement distributions in the vicinity of a crack are determined using a shear lag model. These are incorporated into an energy based cracking criterion to determine the favorability of crack formation. A progressive damage algorithm allows the inclusion of material softening effects and temperature-dependent material properties. The analysis is implemented by a computer code which gives predicted crack density and degraded laminate properties as functions of any thermomechanical load history. Extensive experimentation provides verification of the analysis. AS4/3501-6 graphite/epoxy laminates are manufactured with three different layups to investigate ply thickness and orientation effects. Thermal specimens are cooled to progressively lower temperatures down to -184 C. After conditioning the specimens to each temperature, cracks are counted on their edges using optical microscopy and in their interiors by sanding to incremental depths. Tensile coupons are loaded monotonically to progressively higher loads until failure. Cracks are counted on the coupon edges after each loading. A data fit to all available results provides input parameters for the analysis and shows them to be material properties, independent of geometry and loading. Correlation between experiment and analysis is generally very good under both thermal and mechanical loading, showing the methodology to be a powerful, unified tool. Delayed crack initiation observed in a few cases is attributed to a

Spinodal Theory: A Common Rupturing Mechanism in Spinodal Dewetting and Surface Directed Phase Separation (Some Technological Aspects: Spatial Correlations and the Significance of Dipole-Quadrupole Interaction in Spinodal Dewetting)

International Nuclear Information System (INIS)

Singh, S.P.; Singh, S.P.

2011-01-01

The emerging structures in spinodal dewetting of thin nano films and spinodal decomposition of binary mixtures are found to be similar with certain differences attributed to the nonlinearities inherent in the wetting forces. This paper deals with the technological aspects of the spinodal processes by giving a brief account of the theory and to correlate the two phenomena termed as spinodal dewetting of thin nano films and surface-directed phase separation. The MC simulation micrographs at early stage of spinodal dewetting of a (linear) polymer film confined between two hard walls (using FENE potential between the beads on same chain and Morse potential between inter and intra chain beads) show similarities with surface-directed phase separation (using metropolis algorithm) in creation of holes. The spinodal dewetting is also criticized on the basis of global minimization of free energy emerging from dipole-quadrupole interactions. A novel molecular scale-driving mechanism coming from asymmetric interface formation in spinodal processes is also proposed. It can be believed that the modeling done with the films under confinement of two walls works as a classical mathematical Ansatz to the dipole-quadrupole interaction coming from quantum origins and giving rise to lateral interactions in the process reflecting a colossal behavior in thin nano films though weak in nature

Spinodal Theory: A Common Rupturing Mechanism in Spinodal Dewetting and Surface Directed Phase Separation (Some Technological Aspects: Spatial Correlations and the Significance of Dipole-Quadrupole Interaction in Spinodal Dewetting

Directory of Open Access Journals (Sweden)

Satya Pal Singh

2011-01-01

Full Text Available The emerging structures in spinodal dewetting of thin nano films and spinodal decomposition of binary mixtures are found to be similar with certain differences attributed to the nonlinearities inherent in the wetting forces. This paper deals with the technological aspects of the spinodal processes by giving a brief account of the theory and to correlate the two phenomena termed as spinodal dewetting of thin nanofilms and surface-directed phase separation. The MC simulation micrographs at early stage of spinodal dewetting of a (linear polymer film confined between two hard walls (using FENE potential between the beads on same chain and Morse potential between inter and intra chain beads show similarities with surface-directed phase separation (using metropolis algorithm in creation of holes. The spinodal dewetting is also criticized on the basis of global minimization of free energy emerging from dipole-quadrupole interactions. A novel molecular scale-driving mechanism coming from asymmetric interface formation in spinodal processes is also proposed. It can be believed that the modeling done with the films under confinement of two walls works as a classical mathematical ansatz to the dipole-quadrupole interaction coming from quantum origins and giving rise to lateral interactions in the process reflecting a colossal behavior in thin nano films though weak in nature.

An agent-based simulation of power generation company behavior in electricity markets under different market-clearing mechanisms

International Nuclear Information System (INIS)

Aliabadi, Danial Esmaeili; Kaya, Murat; Şahin, Güvenç

2017-01-01

Deregulated electricity markets are expected to provide affordable electricity for consumers through promoting competition. Yet, the results do not always fulfill the expectations. The regulator's market-clearing mechanism is a strategic choice that may affect the level of competition in the market. We conceive of the market-clearing mechanism as composed of two components: pricing rules and rationing policies. We investigate the strategic behavior of power generation companies under different market-clearing mechanisms using an agent-based simulation model which integrates a game-theoretical understanding of the auction mechanism in the electricity market and generation companies' learning mechanism. Results of our simulation experiments are presented using various case studies representing different market settings. The market in simulations is observed to converge to a Nash equilibrium of the stage game or to a similar state under most parameter combinations. Compared to pay-as-bid pricing, bid prices are closer to marginal costs on average under uniform pricing while GenCos' total profit is also higher. The random rationing policy of the ISO turns out to be more successful in achieving lower bid prices and lower GenCo profits. In minimizing GenCos' total profit, a combination of pay-as-bid pricing rule and random rationing policy is observed to be the most promising. - Highlights: • An agent-based simulation of generation company behavior in electricity markets is developed. • Learning dynamics of companies is modeled with an extended Q-learning algorithm. • Different market clearing mechanisms of the regulator are compared. • Convergence to Nash equilibria is analyzed under different cases. • The level of competition in the market is studied.

The mechanisms of collinear integration.

Science.gov (United States)

Cass, John; Alais, David

2006-08-11

Low-contrast visual contour fragments are easier to detect when presented in the context of nearby collinear contour elements (U. Polat & D. Sagi, 1993). The spatial and temporal determinants of this collinear facilitation have been studied extensively (J. R. Cass & B. Spehar, 2005; Y. Tanaka & D. Sagi, 1998; C. B. Williams & R. F. Hess, 1998), although considerable debate surrounds the neural mechanisms underlying it. Our study examines this question using a novel stimulus, whereby the flanking "contour" elements are rotated around their own axis. By measuring contrast detection thresholds to a brief foveal target presented at various phases of flanker rotation, we find peak facilitation after flankers have rotated beyond their collinear phase. This optimal facilitative delay increases monotonically as a function of target-flanker separation, yielding estimates of cortical propagation of 0.1 m/s, a value highly consistent with the dynamics of long-range horizontal interactions observed within primary visual cortex (V1). A curious new finding is also observed: Facilitative peaks also occur when the target flash precedes flanker collinearity by 20-80 ms, a range consistent with contrast-dependent cortical onset latencies. Together, these data suggest that collinear facilitation involves two separate mechanisms, each possessing distinct dynamics: (i) slowly propagating horizontal interactions within V1 and (ii) a faster integrative mechanism, possibly driven by synchronous collinear cortical onset.

Slicer-independent mechanism drives small-RNA strand separation during human RISC assembly.

Science.gov (United States)

Park, June Hyun; Shin, Chanseok

2015-10-30

Small RNA silencing is mediated by the effector RNA-induced silencing complex (RISC) that consists of an Argonaute protein (AGOs 1-4 in humans). A fundamental step during RISC assembly involves the separation of two strands of a small RNA duplex, whereby only the guide strand is retained to form the mature RISC, a process not well understood. Despite the widely accepted view that 'slicer-dependent unwinding' via passenger-strand cleavage is a prerequisite for the assembly of a highly complementary siRNA into the AGO2-RISC, here we show by careful re-examination that 'slicer-independent unwinding' plays a more significant role in human RISC maturation than previously appreciated, not only for a miRNA duplex, but, unexpectedly, for a highly complementary siRNA as well. We discovered that 'slicer-dependency' for the unwinding was affected primarily by certain parameters such as temperature and Mg(2+). We further validate these observations in non-slicer AGOs (1, 3 and 4) that can be programmed with siRNAs at the physiological temperature of humans, suggesting that slicer-independent mechanism is likely a common feature of human AGOs. Our results now clearly explain why both miRNA and siRNA are found in all four human AGOs, which is in striking contrast to the strict small-RNA sorting system in Drosophila. © The Author(s) 2015. Published by Oxford University Press on behalf of Nucleic Acids Research.

Failure mechanisms of aluminium foams under compressive loads

Directory of Open Access Journals (Sweden)

Sáenz, E.

2000-08-01

Full Text Available The purpose of this paper is the investigation of the major failure mechanisms of aluminium foams, which were obtained by powder metallurgy route, under compressive loads. The study was focused on two commonly aluminium alloys AlMg1Si or A 6061 and AlSi12. Due to the fact that the failure mechanisms strongly depend on the density and the macrostructural properties of the material, the mechanical properties always have to be correlated to the structural properties. Therefore, macrostructural investigations were used as a basis to establish the correlation between structural and mechanical properties. This was done with a commercially available image analysis system. The average cell size, the cell size distribution and the cell density (number of cells/area were obtained. In order to evaluate the influence of foaming direction on the cell morphology, some cross sections parallel to the foaming direction were prepared. For the characterization of the mechanical compression properties the compressive or upper yield strength (UYS, the densification strain (eD, the energy absorption (Ea and the efficiency (Eff were obtained. Furthermore, the failure behavior of the samples was in-situ observed with a digital video camera and continuously recorded during the test.

El objetivo de este estudio es investigar los principales mecanismos de fallo de espumas de aluminio sometidas a cargas de compresión. Las espumas metálicas fueron obtenidas mediante el proceso pulvimetalúrgico, utilizándose como materia prima dos aleaciones comerciales AlMg1Si o A 6061 y AlSi12. Debido a que los mecanismos de fallo en este tipo de materiales depende fuertemente de la densidad y las características macroestructurales del material, en este estudio se busca correlacionar las propiedades mecánicas con estas características. La macroestructura se caracterizó mediante análisis de imagen. El tamaño de celda promedio, la distribución de tamaño y la densidad de

The Immunomodulatory Effects of Macrolides—A Systematic Review of the Underlying Mechanisms

Directory of Open Access Journals (Sweden)

Petra Zimmermann

2018-03-01

Full Text Available BackgroundThe mechanisms underlying the non-antimicrobial immunomodulatory properties of macrolides are not well understood.ObjectivesTo systematically review the evidence for the immunomodulatory properties of macrolides in humans and to describe the underlying mechanism and extent of their influence on the innate and adaptive immune system.MethodsA systematic literature search was done in MEDLINE using the OVID interface from 1946 to December 2016 according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA. Original articles investigating the influence of four macrolides (azithromycin, clarithromycin, erythromycin, and roxithromycin on immunological markers in humans were included.ResultsWe identified 22 randomized, controlled trials, 16 prospective cohort studies, and 8 case–control studies investigating 47 different immunological markers (186 measurements in 1,834 participants. The most frequently reported outcomes were a decrease in the number of neutrophils, and the concentrations of neutrophil elastase, interleukin (IL-8, IL-6, IL-1beta, tumor necrosis factor (TNF-alpha, eosinophilic cationic protein, and matrix metalloproteinase 9. Inhibition of neutrophil function was reported more frequently than eosinophil function. A decrease in T helper (Th 2 cells cytokines (IL-4, IL-5, IL-6 was reported more frequently than a decrease in Th1 cytokines (IL-2, INF-gamma.ConclusionMacrolides influence a broad range of immunological mechanisms resulting in immunomodulatory effects. To optimize the treatment of chronic inflammatory diseases by macrolides, further studies are necessary, particularly comparing different macrolides and dose effect relationships.

Mechanical control over valley magnetotransport in strained graphene

Energy Technology Data Exchange (ETDEWEB)

Ma, Ning, E-mail: maning@stu.xjtu.edu.cn [Department of Physics, MOE Key Laboratory of Advanced Transducers and Intelligent Control System, Taiyuan University of Technology, Taiyuan 030024 (China); Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Zhang, Shengli, E-mail: zhangsl@mail.xjtu.edu.cn [Department of Applied Physics, MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Xi' an Jiaotong University, Xi' an 710049 (China); Liu, Daqing, E-mail: liudq@cczu.edu.cn [School of Mathematics and Physics, Changzhou University, Changzhou 213164 (China)

2016-05-06

Recent experiments report that the graphene exhibits Landau levels (LLs) that form in the presence of a uniform strain pseudomagnetic field with magnitudes up to hundreds of tesla. We further reveal that the strain removes the valley degeneracy in LLs, and leads to a significant valley polarization with inversion symmetry broken. This accordingly gives rise to the well separated valley Hall plateaus and Shubnikov–de Haas oscillations. These effects are absent in strainless graphene, and can be used to generate and detect valley polarization by mechanical means, forming the basis for the new paradigm “valleytronics” applications. - Highlights: • We explore the mechanical strain effects on the valley magnetotransport in graphene. • We analytically derive the dc collisional and Hall conductivities under strain. • The strain removes the valley degeneracy in Landau levels. • The strain causes a significant valley polarization with inversion symmetry broken. • The strain leads to the well separated valley Hall and Shubnikov–de Haas effects.

Effects of delaying transplanting on agronomic traits and grain yield of rice under mechanical transplantation pattern.

Directory of Open Access Journals (Sweden)

Qihua Liu

Full Text Available A delay in the mechanical transplantation (MT of rice seedlings frequently occurs in Huanghuai wheat-rice rotation cropping districts of China, due to the late harvest of wheat, the poor weather conditions and the insufficiency of transplanters, missing the optimum transplanting time and causing seedlings to age. To identify how delaying transplanting rice affects the agronomic characteristics including the growth duration, photosynthetic productivity and dry matter remobilization efficiency and the grain yield under mechanical transplanting pattern, an experiment with a split-plot design was conducted over two consecutive years. The main plot includes two types of cultivation: mechanical transplanting and artificial transplanting (AT. The subplot comprises four japonica rice cultivars. The results indicate that the rice jointing, booting, heading and maturity stages were postponed under MT when using AT as a control. The tiller occurrence number, dry matter weight per tiller, accumulative dry matter for the population, leaf area index, crop growth rate, photosynthetic potential, and dry matter remobilization efficiency of the leaf under MT significantly decreased compared to those under AT. In contrast, the reduction rate of the leaf area during the heading-maturity stage was markedly enhanced under MT. The numbers of effective panicles and filled grains per panicle and the grain yield significantly decreased under MT. A significant correlation was observed between the dry matter production, remobilization and distribution characteristics and the grain yield. We infer that, as with rice from old seedlings, the decrease in the tiller occurrence, the photosynthetic productivity and the assimilate remobilization efficiency may be important agronomic traits that are responsible for the reduced grain yield under MT.

Research on energy conversion mechanism of a screw centrifugal pump under the water

International Nuclear Information System (INIS)

Quan, H; Li, R N; Han, W; Cheng, X R; Shen, Z J; Su, Q M

2013-01-01

In order to research screw centrifugal pump impeller power capability and energy conversion mechanism, we used Navier-Stokes equation and standard k-ε equation turbulence model on the basis of the Euler equations to carry out screw centrifugal pump internal flow numerical simulation. This was explored by simulating specific design conditions; the medium is water, variation of speed and pressure of flow filed under the action of the impeller, and the screw centrifugal impeller shroud line and wheel line segment take monitoring sites. The monitoring points are between dynamic head and static head change to analyze the energy conversion capability along the impeller corners of screw centrifugal pump. The results show that the energy of fluid of the screw centrifugal pump is provided by spiral segment, the spiral segment in front of the impeller has played a multi-level role, it has significant reference value to research the energy conversion mechanism of screw centrifugal pump under solid-liquid two phase

CISM course on mechanical behaviour of soils under environmentally induced cyclic loads

CERN Document Server

Wood, David; Mechanical Behaviour of Soils Under Environmentally Induced Cyclic Loads

2012-01-01

The book gives a comprehensive description of the mechanical response of soils (granular and cohesive materials) under cyclic loading. It provides the geotechnical engineer with the theoretical and analytical tools necessary for the evaluation of settlements developng with time under cyclic, einvironmentally idncued loads (such as wave motion, wind actions, water table level variation) and their consequences for the serviceability and durability of structures such as the shallow or deep foundations used in offshore engineering, caisson beakwaters, ballast and airport pavements and also to interpret monitoring data, obtained from both natural and artificial slopes and earth embankments, for the purposes of risk assessment and mitigation.

Biological mechanisms underlying the role of physical fitness in health and resilience

OpenAIRE

Silverman, Marni N.; Deuster, Patricia A.

2014-01-01

Physical fitness, achieved through regular exercise and/or spontaneous physical activity, confers resilience by inducing positive psychological and physiological benefits, blunting stress reactivity, protecting against potentially adverse behavioural and metabolic consequences of stressful events and preventing many chronic diseases. In this review, we discuss the biological mechanisms underlying the beneficial effects of physical fitness on mental and physical health. Physical fitness appear...

Contact mechanics: contact area and interfacial separation from small contact to full contact

International Nuclear Information System (INIS)

Yang, C; Persson, B N J

2008-01-01

We present a molecular dynamics study of the contact between a rigid solid with a randomly rough surface and an elastic block with a flat surface. The numerical calculations mainly focus on the contact area and the interfacial separation from small contact (low load) to full contact (high load). For a small load the contact area varies linearly with the load and the interfacial separation depends logarithmically on the load. For a high load the contact area approaches the nominal contact area (i.e. complete contact), and the interfacial separation approaches zero. The numerical results have been compared with analytical theory and experimental results. They are in good agreement with each other. The present findings may be very important for soft solids, e.g. rubber, or for very smooth surfaces, where complete contact can be reached at moderately high loads without plastic deformation of the solids

Atomic vapor laser isotope separation

International Nuclear Information System (INIS)

Stern, R.C.; Paisner, J.A.

1985-01-01

Atomic vapor laser isotope separation (AVLIS) is a general and powerful technique. A major present application to the enrichment of uranium for light-water power reactor fuel has been under development for over 10 years. In June 1985 the Department of Energy announced the selection of AVLIS as the technology to meet the nation's future need for the internationally competitive production of uranium separative work. The economic basis for this decision is considered, with an indicated of the constraints placed on the process figures of merit and the process laser system. We then trace an atom through a generic AVLIS separator and give examples of the physical steps encountered, the models used to describe the process physics, the fundamental parameters involved, and the role of diagnostic laser measurements

Mechanical measurement of hydrogen bonded host-guest systems under non-equilibrium, near-physiological conditions.

Science.gov (United States)

Naranjo, Teresa; Cerrón, Fernando; Nieto-Ortega, Belén; Latorre, Alfonso; Somoza, Álvaro; Ibarra, Borja; Pérez, Emilio M

2017-09-01

Decades after the birth of supramolecular chemistry, there are many techniques to measure noncovalent interactions, such as hydrogen bonding, under equilibrium conditions. As ensembles of molecules rapidly lose coherence, we cannot extrapolate bulk data to single-molecule events under non-equilibrium conditions, more relevant to the dynamics of biological systems. We present a new method that exploits the high force resolution of optical tweezers to measure at the single molecule level the mechanical strength of a hydrogen bonded host-guest pair out of equilibrium and under near-physiological conditions. We utilize a DNA reporter to unambiguously isolate single binding events. The Hamilton receptor-cyanuric acid host-guest system is used as a test bed. The force required to dissociate the host-guest system is ∼17 pN and increases with the pulling rate as expected for a system under non-equilibrium conditions. Blocking one of the hydrogen bonding sites results in a significant decrease of the force-to-break by 1-2 pN, pointing out the ability of the method to resolve subtle changes in the mechanical strength of the binding due to the individual H-bonding components. We believe the method will prove to be a versatile tool to address important questions in supramolecular chemistry.

Electron exchange reaction in anion exchangers as observed in uranium isotope separation

International Nuclear Information System (INIS)

Obanawa, Heiichiro; Takeda, Kunihiko; Seko, Maomi

1991-01-01

The mechanism of electron exchange in an ion exchanger, as occurring between U 4+ and UO 2 2+ in uranium isotope separation, was investigated. The height of the separation unit (H q ) in the presence of metal ion catalysts, as obtained from the separation experiments, was found to be almost coincident with the theoretical value of H q as calculated on the basis of the intrasolution acceleration mechanism of the metal ion, suggesting that the electron exchange mechanism in the ion-exchanger is essentially the same as that in the solution when metal ion catalysts are present. Separation experiments with no metal ion catalyst, on the other hand, showed the electron exchange reaction in the ion exchanger to be substantially higher than that in the solution, suggesting an acceleration of the electron exchange reaction by the ion-exchanger which is due to the close existence of higher order Cl - complexes of UO 2 2+ and U 4+ in the vicinity of the ion-exchange group. (author)

Neuro-cognitive mechanisms underlying the emotional modulation of word reading

Institute of Scientific and Technical Information of China (English)

无

2006-01-01

A novel neural model for emotional modulation of word reading is proposed. This model has four principal hypotheses: the dominant activation region hypothesis, the emotional modulation hypothesis, the attentional level hypothesis, and the interaction hypothesis. Four lines of research were reviewed to provide evidence for these hypotheses: (1) neuro-cognitive studies on the mechanisms of word reading (i.e., neural networks for reading); (2) studies on the influence of words' emotional valence on word reading; (3) studies of the effect of attention on word reading; and (4) studies on emotional modulation of word reading under different attentional levels.

Investigation of deterioration mechanism of electrical ceramic insulating materials under high temperature

International Nuclear Information System (INIS)

Mizutani, Yoshinobu; Ito, Tetsuo; Okamoto, Tatsuki; Kumazawa, Ryoji; Aizawa, Rie; Moriyama, Hideshige

2000-01-01

It is thought that ceramic insulator can be applied to electric power equipments that are under high temperature not to be able use organic materials. Our research has suggested components of mica-alumina combined insulation. As the results of and carried out temperature accelerating test, combined insulation life is expected long term over 40 years at over 500-Celsius degrees. However to construct high reliable insulating system, it is clarified deterioration mechanism on combined insulation and evaluates life of that. Therefore we carried out metal behavior test and voltage aging test using mica-sheet and alumina-cloth that are components of combined insulation under high temperature in nitrogen gas atmosphere. It is cleared two metal behavior mechanisms: One is that the opening of insulator are filled up with copper that is oxidized, the other is the metal diffuses in alumina-cloth through surface. And distance of metal behavior is able to be estimated at modulate temperature and in modulate time. It is also cleared that alumina-cloth is deteriorated by metal behavior into alumina-cloth. These results indicate that combined insulation is deteriorated from electrode side by metal behavior and is finally broken down through alumina-cloth. (author)

Mechanical behavior of glass/epoxy composite laminate with varying amount of MWCNTs under different loadings

Science.gov (United States)

Singh, K. K.; Rawat, Prashant

2018-05-01

This paper investigates the mechanical response of three phased (glass/MWCNTs/epoxy) composite laminate under three different loadings. Flexural strength, short beam strength and low-velocity impact (LVI) testing are performed to find an optimum doping percentage value for maximum enhancement in mechanical properties. In this work, MWCNTs were used as secondary reinforcement for three-phased composite plate. MWCNT doping was done in a range of 0–4 wt% of the thermosetting matrix system. Symmetrical design eight layered glass/epoxy laminate with zero bending extension coupling laminate was fabricated using a hybrid method i.e. hand lay-up technique followed by vacuum bagging method. Ranging analysis of MWCNT mixing highlighted the enhancement in flexural, short beam strength and improvement in damage tolerance under LVI loading. While at higher doping wt%, agglomeration of MWCNTs are observed. Results of mechanical testing proposed an optimized doping value for maximum strength and damage resistance of the laminate.

Mechanical characteristics under monotonic and cyclic simple shear of spark plasma sintered ultrafine-grained nickel

International Nuclear Information System (INIS)

Dirras, G.; Bouvier, S.; Gubicza, J.; Hasni, B.; Szilagyi, T.

2009-01-01

The present work focuses on understanding the mechanical behavior of bulk ultrafine-grained nickel specimens processed by spark plasma sintering of high purity nickel nanopowder and subsequently deformed under large amplitude monotonic simple shear tests and strain-controlled cyclic simple shear tests at room temperature. During cyclic tests, the samples were deformed up to an accumulated von Mises strain of about ε VM = 0.75 (the flow stress was in the 650-700 MPa range), which is extremely high in comparison with the low tensile/compression ductility of this class of materials at quasi-static conditions. The underlying physical mechanisms were investigated by electron microscopy and X-ray diffraction profile analysis. Lattice dislocation-based plasticity leading to cell formation and dislocation interactions with twin boundaries contributed to the work-hardening of these materials. The large amount of plastic strain that has been reached during the shear tests highlights intrinsic mechanical characteristics of the ultrafine-grained nickel studied here.

Mechanical characteristics under monotonic and cyclic simple shear of spark plasma sintered ultrafine-grained nickel

Energy Technology Data Exchange (ETDEWEB)

Dirras, G., E-mail: dirras@univ-paris13.fr [LPMTM - CNRS, Institut Galilee, Universite Paris 13, 99 Avenue J.B. Clement, 93430 Villetaneuse (France); Bouvier, S. [LPMTM - CNRS, Institut Galilee, Universite Paris 13, 99 Avenue J.B. Clement, 93430 Villetaneuse (France); Gubicza, J. [Department of Materials Physics, Eoetvoes Lorand University, P.O.B. 32, Budapest H-1518 (Hungary); Hasni, B. [LPMTM - CNRS, Institut Galilee, Universite Paris 13, 99 Avenue J.B. Clement, 93430 Villetaneuse (France); Szilagyi, T. [Department of Materials Physics, Eoetvoes Lorand University, P.O.B. 32, Budapest H-1518 (Hungary)

2009-11-25

The present work focuses on understanding the mechanical behavior of bulk ultrafine-grained nickel specimens processed by spark plasma sintering of high purity nickel nanopowder and subsequently deformed under large amplitude monotonic simple shear tests and strain-controlled cyclic simple shear tests at room temperature. During cyclic tests, the samples were deformed up to an accumulated von Mises strain of about {epsilon}{sub VM} = 0.75 (the flow stress was in the 650-700 MPa range), which is extremely high in comparison with the low tensile/compression ductility of this class of materials at quasi-static conditions. The underlying physical mechanisms were investigated by electron microscopy and X-ray diffraction profile analysis. Lattice dislocation-based plasticity leading to cell formation and dislocation interactions with twin boundaries contributed to the work-hardening of these materials. The large amount of plastic strain that has been reached during the shear tests highlights intrinsic mechanical characteristics of the ultrafine-grained nickel studied here.

Intercomparison of chemical mechanisms for air quality policy formulation and assessment under North American conditions.

Science.gov (United States)

Derwent, Richard

2017-07-01

The intercomparison of seven chemical mechanisms for their suitability for air quality policy formulation and assessment is described. Box modeling techniques were employed using 44 sets of background environmental conditions covering North America to constrain the chemical development of the longer lived species. The selected mechanisms were modified to enable an unbiased assessment of the adequacy of the parameterizations of photochemical ozone production from volatile organic compound (VOC) oxidation in the presence of NO x . Photochemical ozone production rates responded differently to 30% NO x and VOC reductions with the different mechanisms, despite the striking similarities between the base-case ozone production rates. The 30% reductions in NO x and VOCs also produced changes in OH. The responses in OH to 30% reductions in NO x and VOCs appeared to be more sensitive to mechanism choice, compared with the responses in the photochemical ozone production rates. Although 30% NO x reductions generally led to decreases in OH, 30% reductions in VOCs led to increases in OH, irrespective of mechanism choice and background environmental conditions. The different mechanisms therefore gave different OH responses to NO x and VOC reductions and so would give different responses in terms of changes in the fate and behavior of air toxics, acidification and eutrophication, and fine particle formation compared with others, in response to ozone control strategies. Policymakers need to understand that there are likely to be inherent differences in the responses to ozone control strategies between different mechanisms, depending on background environmental conditions and the extents of NO x and VOC reductions under consideration. The purpose of this paper is to compare predicted ozone responses to NO x and VOC reductions with seven chemical mechanisms under North American conditions. The good agreement found between the tested mechanisms should provide some support for their

Experimental Investigation on Shock Mechanical Properties of Red Sandstone under Preloaded 3D Static Stresses

Directory of Open Access Journals (Sweden)

Niu Yong

2015-11-01

Full Text Available Triaxial impact mechanical performance experiment was performed to study the mechanical properties of red sandstone subjected to three-dimensional (3D coupled static and dynamic loads, i.e., three confining pressures (0, 5, and 10 MPa and three axial pressures (11, 27, and 43 MPa. A modified 3D split Hopkinson pressure bar testing system was used. The change trend in the deformation of red sandstone and the strength and failure modes under axial pressures and confining pressures were analyzed. Results show that, when the confining pressure is constant, the compressive strength, secant modulus, and energy absorbed per unit volume of red sandstone initially increases and subsequently decreases, whereas the average strain rate exhibits an opposite trend. When the axial pressure is constant, both the compressive strength and secant modulus of red sandstone are enhanced, but the average strain rate is decreased with increasing confining pressure. The energy absorbed per unit volume is initially increased and subsequently decreased as the confining pressure increases. Red sandstone exhibits a cone-shaped compression–shear failure mode under the 3D coupled static and dynamic loads. The conclusions serve as theoretical basis on the mechanical properties of deep medium-strength rock under a high ground stress and external load disturbance condition

Centrifugal separation for miscible solutions: Fundamentals and applications to separation of molten salt nuclear material

International Nuclear Information System (INIS)

Li Ning; Camassa, Roberto; Ecke, Robert E.; Venneri, Francesco

1995-01-01

We report on the physical separation of dilute solutions using centrifugal techniques. We use numerical simulations of the diffusion and sedimentation dynamics of centrifugation to model the approach to an equilibrium concentration profile. We verify experimentally the equilibrium profiles for aqueous solutions of different salts under rotation at 25000 rpm corresponding to centrifugal accelerations of about 57,000 g and 75,000 g in two different commercial centrifuges. These measurements provide ratios of sedimentation and diffusion coefficients. We show experimental results for the dynamics of separation that confirm the predictions of the theoretical model. We also measure the mass diffusion coefficient for several solutions. Although the relaxation to equilibrium is long, we have determined a method for efficiently extracting enriched components from a ternary mixture based on fast dynamics at early times. These dynamics are modeled in numerical simulations with realistic fluid parameters. Based on these studies we show that a multistage centrifugal separation process could provide efficient physical separation of actinides and fission products from a molten-salt solution in proposed transmutation/energy-production systems. We consider technical issues in the design of such a separation system

Centrifugal separation for miscible solutions: Fundamentals and applications to separation of molten salt nuclear material

International Nuclear Information System (INIS)

Ning Li; Camassa, R.; Ecke, R.E.

1995-01-01

The authors report on the physical separation of dilute solutions using centrifugal techniques. They use numerical simulations of the diffusion and sedimentation dynamics of centrifugation to model the approach to an equilibrium concentration profile. They verify experimentally the equilibrium profiles for aqueous solutions of different salts under rotation at 25000 rpm corresponding to centrifugal accelerations of about 57,000 g and 75,000 g in two different commercial centrifuges. These measurements provide ratios of sedimentation and diffusion coefficients. The authors show experimental results for the dynamics of separation that confirm the predictions of the theoretical model. They also measure the mass diffusion coefficient for several solutions. Although the relaxation to equilibrium is long, they have determined a method for efficiently extracting enriched components from a ternary mixture based on fast dynamics at early times. These dynamics are modeled in numerical simulations with realistic fluid parameters. Based on these studies the authors show that a multistage centrifugal separation process could provide efficient physical separation of actinides and fission products from a molten-salt solution in proposed transmutation/energy-production systems. The authors consider technical issues in the design of such a separation system

Centrifugal separation for miscible solutions: Fundamentals and applications to separation of molten salt nuclear material

Energy Technology Data Exchange (ETDEWEB)

Ning Li; Camassa, R.; Ecke, R.E. [Los Alamos National Laboratory, NM (United States)] [and others

1995-10-01

The authors report on the physical separation of dilute solutions using centrifugal techniques. They use numerical simulations of the diffusion and sedimentation dynamics of centrifugation to model the approach to an equilibrium concentration profile. They verify experimentally the equilibrium profiles for aqueous solutions of different salts under rotation at 25000 rpm corresponding to centrifugal accelerations of about 57,000 g and 75,000 g in two different commercial centrifuges. These measurements provide ratios of sedimentation and diffusion coefficients. The authors show experimental results for the dynamics of separation that confirm the predictions of the theoretical model. They also measure the mass diffusion coefficient for several solutions. Although the relaxation to equilibrium is long, they have determined a method for efficiently extracting enriched components from a ternary mixture based on fast dynamics at early times. These dynamics are modeled in numerical simulations with realistic fluid parameters. Based on these studies the authors show that a multistage centrifugal separation process could provide efficient physical separation of actinides and fission products from a molten-salt solution in proposed transmutation/energy-production systems. The authors consider technical issues in the design of such a separation system.

An Improved CO2 Separation and Purification System Based on Cryogenic Separation and Distillation Theory

Directory of Open Access Journals (Sweden)

Gang Xu

2014-05-01

Full Text Available In this study, an improved CO2 separation and purification system is proposed based on in-depth analyses of cryogenic separation and distillation theory as well as the phase transition characteristics of gas mixtures containing CO2. Multi-stage compression, refrigeration, and separation are adopted to separate the majority of the CO2 from the gas mixture with relatively low energy penalty and high purity. Subsequently, the separated crude liquid CO2 is distilled under high pressure and near ambient temperature conditions so that low energy penalty purification is achieved. Simulation results indicate that the specific energy consumption for CO2 capture is only 0.425 MJ/kgCO2 with 99.9% CO2 purity for the product. Techno-economic analysis shows that the total plant investment is relatively low. Given its technical maturity and great potential in large-scale production, compared to conventional MEA and SelexolTM absorption methods, the cost of CO2 capture of the proposed system is reduced by 57.2% and 45.9%, respectively. The result of this study can serve as a novel approach to recovering CO2 from high CO2 concentration gas mixtures.

Interactivity effects in social media marketing on brand engagement: an investigation of underlying mechanisms

NARCIS (Netherlands)

Antheunis, M.L.; van Noort, G.; Eisend, M.; Langner, T.

2011-01-01

Although, SNS advertising spending increases, research on SNS campaigning is still underexposed. First, this study aims to investigate the effect of SNS campaign interactivity on the receivers brand engagement, taking four underlying mechanisms into account (brand identification, campaign

Hardening and softening mechanisms of pearlitic steel wire under torsion

International Nuclear Information System (INIS)

Zhao, Tian-Zhang; Zhang, Shi-Hong; Zhang, Guang-Liang; Song, Hong-Wu; Cheng, Ming

2014-01-01

Highlights: • Mechanical behavior of pearlitic steel wire is studied using torsion. • Work hardening results from refinement lamellar pearlitic structure. • Softening results from recovery, shear bands and lamellar fragmentations. • A microstructure based analytical flow stress model is established. - Abstract: The mechanical behaviors and microstructure evolution of pearlitic steel wires under monotonic shear deformation have been investigated by a torsion test and a number of electron microscopy techniques including scanning electron microscopy (SEM) and transmission electron microscopy (TEM), with an aim to reveal the softening and hardening mechanisms of a randomly oriented pearlitic structure during a monotonic stain path. Significantly different from the remarkable strain hardening in cold wire drawing, the strain hardening rate during torsion drops to zero quickly after a short hardening stage. The microstructure observations indicate that the inter-lamellar spacing (ILS) decreases and the dislocations accumulate with strain, which leads to hardening of the material. Meanwhile, when the strain is larger than 0.154, the enhancement of dynamic recovery, shear bands (SBs) and cementite fragmentations results in the softening and balances the strain hardening. A microstructure based analytical flow stress model with considering the influence of ILS on the mean free path of dislocations and the softening caused by SBs and cementite fragmentations, has been established and the predicted flow shear curve meets well with the measured curve in the torsion test

Hydrothermally stable molecular separation membranes from organically linked silica

Energy Technology Data Exchange (ETDEWEB)

Castricum, H.L.; Sah, A; Blank, D.H.A.; Ten Elshof, J.E. [Inorganic Materials Science, MESA Institute for Nanotechnology, University of Twente, P.O. Box 217, 7500 AE Enschede (Netherlands); Kreiter, R.; Vente, J.F. [ECN Energy Efficiency in the Industry, Petten (Netherlands)

2008-06-15

A highly hydrothermally stable microporous network material has been developed that can be applied in energy-efficient molecular sieving. The material was synthesized by employing organically bridged monomers in acid-catalysed sol-gel hydrolysis and condensation, and is composed of covalently bonded organic and inorganic moieties. Due to its hybrid nature, it withstands higher temperatures than organic polymers and exhibits high solvolytical and acid stability. A thin film membrane that was prepared with the hybrid material was found to be stable in the dehydration of n-butanol at 150C for almost two years. This membrane is the first that combines a high resistance against water at elevated temperatures with a high separation factor and permeance. It therefore has high potential for energy-efficient molecular separation under industrial conditions, including the dehydration of organic solvents. The organically bridged monomers induce increased toughness in the thin film layer. This suppresses hydrolysis of Si-O-Si network bonds and results in a high resistance towards stress-induced cracking. The large non-hydrolysable units thus remain well incorporated in the surrounding matrix such that the material combines high (pore) structural and mechanical stability. The sol mean particle size was found to be a viable parameter to tune the thickness of the membrane layer and thus optimize the separation performance. We anticipate that other hybrid organosilicas can be made in a similar fashion, to yield a whole new class of materials with superior molecular sieving properties and high hydrothermal stability.

Recycling silicon wire-saw slurries: separation of silicon and silicon carbide in a ramp settling tank under an applied electrical field.

Science.gov (United States)

Tsai, Tzu-Hsuan; Shih, Yu-Pei; Wu, Yung-Fu

2013-05-01

The growing demand for silicon solar cells in the global market has greatly increased the amount of silicon sawing waste produced each year. Recycling kerf Si and SiC from sawing waste is an economical method to reduce this waste. This study reports the separation of Si and SiC using a ramp settling tank. As they settle in an electrical field, small Si particles with higher negative charges have a longer horizontal displacement than SiC particles in a solution of pH 7, resulting in the separation of Si and SiC. The agreement between experimental results and predicted results shows that the particles traveled a short distance to reach the collection port in the ramp tank. Consequently, the time required for tiny particles to hit the tank bottom decreased, and the interference caused by the dispersion between particles and the fluid motion during settling decreased. In the ramp tank, the highest purities of the collected SiC and Si powders were 95.2 and 7.01 wt%, respectively. Using a ramp tank, the recycling fraction of Si-rich powders (SiC tanks. Recycling Si and SiC abrasives from the silicon sawing waste is regarded as an economical solution to reduce the sawing waste. However, the separation of Si and SiC is difficult. This study reports the separation of Si and SiC using a ramp settling tank under an applied electrical field. As they settle in an electrical field, small Si particles with higher negative charges have a longer horizontal displacement than SiC particles in a solution of pH 7, resulting in the separation of Si and SiC. Compared with the rectangular tanks, the recycling fraction of Si-rich powders using a ramp tank is greater, and the proposed ramp settling tank is more suitable for industrial applications.

Ultrastructural changes of cell walls under intense mechanical treatment of selective plant raw material

International Nuclear Information System (INIS)

Bychkov, Aleksey L.; Ryabchikova, E.I.; Korolev, K.G.; Lomovsky, O.I.

2012-01-01

Structural changes of cell walls under intense mechanical treatment of corn straw and oil-palm fibers were studied by electron and light microscopy. Differences in the character of destruction of plant biomass were revealed, and the dependence of destruction mechanisms on the structure of cell walls and lignin content was demonstrated. We suggest that the high reactivity of the particles of corn straw (about 18% of lignin) after intense mechanical treatment is related to disordering of cell walls and an increase of the surface area, while in the case of oil palm (10% of lignin) the major contribution into an increase in the reactivity is made by an increase of surface area. -- Highlights: ► Structure of cell walls determines the processes of plant materials' destruction. ► Ultrastructure of highly lignified materials strongly disordering by mechanical action. ► Ultrastructure of low-lignified materials is not disordering by mechanical action.

Chiral recognition in separation science: an overview.

Science.gov (United States)

Scriba, Gerhard K E

2013-01-01

Chiral recognition phenomena play an important role in nature as well as analytical separation sciences. In separation sciences such as chromatography and capillary electrophoresis, enantiospecific interactions between the enantiomers of an analyte and the chiral selector are required in order to observe enantioseparations. Due to the large structural variety of chiral selectors applied, different mechanisms and structural features contribute to the chiral recognition process. This chapter briefly illustrates the current models of the enantiospecific recognition on the structural basics of various chiral selectors.

Rare earth separations by selective borate crystallization

Science.gov (United States)

Yin, Xuemiao; Wang, Yaxing; Bai, Xiaojing; Wang, Yumin; Chen, Lanhua; Xiao, Chengliang; Diwu, Juan; Du, Shiyu; Chai, Zhifang; Albrecht-Schmitt, Thomas E.; Wang, Shuao

2017-03-01

Lanthanides possess similar chemical properties rendering their separation from one another a challenge of fundamental chemical and global importance given their incorporation into many advanced technologies. New separation strategies combining green chemistry with low cost and high efficiency remain highly desirable. We demonstrate that the subtle bonding differences among trivalent lanthanides can be amplified during the crystallization of borates, providing chemical recognition of specific lanthanides that originates from Ln3+ coordination alterations, borate polymerization diversity and soft ligand coordination selectivity. Six distinct phases are obtained under identical reaction conditions across lanthanide series, further leading to an efficient and cost-effective separation strategy via selective crystallization. As proof of concept, Nd/Sm and Nd/Dy are used as binary models to demonstrate solid/aqueous and solid/solid separation processes. Controlling the reaction kinetics gives rise to enhanced separation efficiency of Nd/Sm system and a one-step quantitative separation of Nd/Dy with the aid of selective density-based flotation.

Molecular mechanisms underlying formation of long-term reward memories and extinction memories in the honeybee (Apis mellifera)

Science.gov (United States)

2014-01-01

The honeybee (Apis mellifera) has long served as an invertebrate model organism for reward learning and memory research. Its capacity for learning and memory formation is rooted in the ecological need to efficiently collect nectar and pollen during summer to ensure survival of the hive during winter. Foraging bees learn to associate a flower's characteristic features with a reward in a way that resembles olfactory appetitive classical conditioning, a learning paradigm that is used to study mechanisms underlying learning and memory formation in the honeybee. Due to a plethora of studies on appetitive classical conditioning and phenomena related to it, the honeybee is one of the best characterized invertebrate model organisms from a learning psychological point of view. Moreover, classical conditioning and associated behavioral phenomena are surprisingly similar in honeybees and vertebrates, suggesting a convergence of underlying neuronal processes, including the molecular mechanisms that contribute to them. Here I review current thinking on the molecular mechanisms underlying long-term memory (LTM) formation in honeybees following classical conditioning and extinction, demonstrating that an in-depth analysis of the molecular mechanisms of classical conditioning in honeybees might add to our understanding of associative learning in honeybees and vertebrates. PMID:25225299

Using Drosophila to discover mechanisms underlying type 2 diabetes

Directory of Open Access Journals (Sweden)

Ronald W. Alfa

2016-04-01

Full Text Available Mechanisms of glucose homeostasis are remarkably well conserved between the fruit fly Drosophila melanogaster and mammals. From the initial characterization of insulin signaling in the fly came the identification of downstream metabolic pathways for nutrient storage and utilization. Defects in these pathways lead to phenotypes that are analogous to diabetic states in mammals. These discoveries have stimulated interest in leveraging the fly to better understand the genetics of type 2 diabetes mellitus in humans. Type 2 diabetes results from insulin insufficiency in the context of ongoing insulin resistance. Although genetic susceptibility is thought to govern the propensity of individuals to develop type 2 diabetes mellitus under appropriate environmental conditions, many of the human genes associated with the disease in genome-wide association studies have not been functionally studied. Recent advances in the phenotyping of metabolic defects have positioned Drosophila as an excellent model for the functional characterization of large numbers of genes associated with type 2 diabetes mellitus. Here, we examine results from studies modeling metabolic disease in the fruit fly and compare findings to proposed mechanisms for diabetic phenotypes in mammals. We provide a systematic framework for assessing the contribution of gene candidates to insulin-secretion or insulin-resistance pathways relevant to diabetes pathogenesis.

Printed Spacecraft Separation System

Energy Technology Data Exchange (ETDEWEB)

Dehoff, Ryan R [ORNL; Holmans, Walter [Planetary Systems Corporation

2016-10-01

In this project Planetary Systems Corporation proposed utilizing additive manufacturing (3D printing) to manufacture a titanium spacecraft separation system for commercial and US government customers to realize a 90% reduction in the cost and energy. These savings were demonstrated via “printing-in” many of the parts and sub-assemblies into one part, thus greatly reducing the labor associated with design, procurement, assembly and calibration of mechanisms. Planetary Systems Corporation redesigned several of the components of the separation system based on additive manufacturing principles including geometric flexibility and the ability to fabricate complex designs, ability to combine multiple parts of an assembly into a single component, and the ability to optimize design for specific mechanical property targets. Shock absorption was specifically targeted and requirements were established to attenuate damage to the Lightband system from shock of initiation. Planetary Systems Corporation redesigned components based on these requirements and sent the designs to Oak Ridge National Laboratory to be printed. ORNL printed the parts using the Arcam electron beam melting technology based on the desire for the parts to be fabricated from Ti-6Al-4V based on the weight and mechanical performance of the material. A second set of components was fabricated from stainless steel material on the Renishaw laser powder bed technology due to the improved geometric accuracy, surface finish, and wear resistance of the material. Planetary Systems Corporation evaluated these components and determined that 3D printing is potentially a viable method for achieving significant cost and savings metrics.

The underlying mechanism of action for various medicinal properties of Piper betle (betel).

Science.gov (United States)

Haslan, H; Suhaimi, F H; Thent, Zar Chi; Das, S

2015-01-01

Piper betle (betel) plant belongs to the Piperaceae family. Piper. betle is widely known for its potent medicinal properties. Various active compounds are present in Piper. betle such as allylpyrocatechol, hydroxychavicol, piperbetol, ethylpiperbetol, piperol A, piperol B, chavibetol, and alkaloids which account for these beneficial medicinal properties. In the present narrative review, we looked into the various active compounds present in the Piper betle and attempted to understand their underlying mechanism of action. Proper understanding of the molecular biology involving the mechanism of action may help in better drug formulation and provide better therapeutic actions in the field of alternative and complementary medicine.

Mechanical Modeling of a WIPP Drum Under Pressure

Energy Technology Data Exchange (ETDEWEB)

Smith, Jeffrey A. [Sandia National Laboratories, Albuquerque, NM (United States)

2014-11-25

Mechanical modeling was undertaken to support the Waste Isolation Pilot Plant (WIPP) technical assessment team (TAT) investigating the February 14th 2014 event where there was a radiological release at the WIPP. The initial goal of the modeling was to examine if a mechanical model could inform the team about the event. The intention was to have a model that could test scenarios with respect to the rate of pressurization. It was expected that the deformation and failure (inability of the drum to contain any pressure) would vary according to the pressurization rate. As the work progressed there was also interest in using the mechanical analysis of the drum to investigate what would happen if a drum pressurized when it was located under a standard waste package. Specifically, would the deformation be detectable from camera views within the room. A finite element model of a WIPP 55-gallon drum was developed that used all hex elements. Analyses were conducted using the explicit transient dynamics module of Sierra/SM to explore potential pressurization scenarios of the drum. Theses analysis show similar deformation patterns to documented pressurization tests of drums in the literature. The calculated failure pressures from previous tests documented in the literature vary from as little as 16 psi to 320 psi. In addition, previous testing documented in the literature shows drums bulging but not failing at pressures ranging from 69 to 138 psi. The analyses performed for this study found the drums failing at pressures ranging from 35 psi to 75 psi. When the drums are pressurized quickly (in 0.01 seconds) there is significant deformation to the lid. At lower pressurization rates the deformation of the lid is considerably less, yet the lids will still open from the pressure. The analyses demonstrate the influence of pressurization rate on deformation and opening pressure of the drums. Analyses conducted with a substantial mass on top of the closed drum demonstrate that the

Isotope separation by standing waves

International Nuclear Information System (INIS)

Altshuler, S.

1984-01-01

The separation of isotopes is accomplished by scattering a beam of particles from a standing electromagnetic wave. The particles may consist of either atoms or molecules, the beam having in either case a desired isotope and at least one other. The particle beam is directed so as to impinge on the standing electromagnetic wave, which may be a light wave. The particles, that is, the atomic or molecular quantum-mechanical waves, see basically a diffraction grating corresponding to the troughs and peaks of the electromagnetic wave. The frequency of the standing electromagnetic wave substantially corresponds to an internal energy level-transition of the desired isotope. Accordingly, the desired isotope is spatially separated by being scattered or diffracted. (author)

Molecular Mechanism of Somite Development

Directory of Open Access Journals (Sweden)

Gulfidan Coskun

2013-06-01

Full Text Available From third week of gestation, notochord and the neural folds begin to gather at the center of the embryo to form the paraxial mesoderm. Paraxial mesoderm separates into blocks of cells called somitomers at the lateral sides of the neural tube of the head region. At the beginning of the third week somitomeres take ring shapes and form blocks of somites from occipital region to caudal region. Although somites are transient structures, they are extremely important in organizing the segmental pattern of vertebrate embryos. Somites give rise to the cells that form the vertebrae and ribs, the dermis of the dorsal skin, the skeletal muscles of the back, and the skeletal muscles of the body wall and limbs. Somitogenesis are formed by a genetic mechanism that is regulated by cyclical expression of genes in the Notch, Wnt and fibroblast growth factor signaling pathways. The prevailing model of the mechanism governing somitogenesis is the “clock and wave front”. Somitogenesis has components of periodicity, separation, epithelialization and axial specification. According to this model, the clock causes cells to undergo repeated oscillations, with a particular phase of each oscillation defining the competency of cells in the presomitic mesoderm to form a somite. Any disruption in this mechanism can be cause of severe segmentation defects of the vertebrae and congenital anomalies. In this review, we discuss the molecular mechanisms underlying the somitogenesis which is an important part of morphogenesis. [Archives Medical Review Journal 2013; 22(3.000: 362-376

Peripheral afferent mechanisms underlying acupuncture inhibition of cocaine behavioral effects in rats.

Directory of Open Access Journals (Sweden)

Seol Ah Kim

Full Text Available Administration of cocaine increases locomotor activity by enhancing dopamine transmission. To explore the peripheral mechanisms underlying acupuncture treatment for drug addiction, we developed a novel mechanical acupuncture instrument (MAI for objective mechanical stimulation. The aim of this study was to evaluate whether acupuncture inhibition of cocaine-induced locomotor activity is mediated through specific peripheral nerves, the afferents from superficial or deep tissues, or specific groups of nerve fibers. Mechanical stimulation of acupuncture point HT7 with MAI suppressed cocaine-induced locomotor activity in a stimulus time-dependent manner, which was blocked by severing the ulnar nerve or by local anesthesia. Suppression of cocaine-induced locomotor activity was elicited after HT7 stimulation at frequencies of either 50 (for Meissner corpuscles or 200 (for Pacinian corpuscles Hz and was not affected by block of C/Aδ-fibers in the ulnar nerve with resiniferatoxin, nor generated by direct stimulation of C/Aδ-fiber afferents with capsaicin. These findings suggest that HT7 inhibition of cocaine-induced locomotor activity is mediated by A-fiber activation of ulnar nerve that originates in superficial and deep tissue.

Mechanical characterisation of porcine rectus sheath under uniaxial and biaxial tension.

LENUS (Irish Health Repository)

Lyons, Mathew

2014-06-03

Incisional hernia development is a significant complication after laparoscopic abdominal surgery. Intra-abdominal pressure (IAP) is known to initiate the extrusion of intestines through the abdominal wall, but there is limited data on the mechanics of IAP generation and the structural properties of rectus sheath. This paper presents an explanation of the mechanics of IAP development, a study of the uniaxial and biaxial tensile properties of porcine rectus sheath, and a simple computational investigation of the tissue. Analysis using Laplace׳s law showed a circumferential stress in the abdominal wall of approx. 1.1MPa due to an IAP of 11kPa, commonly seen during coughing. Uniaxial and biaxial tensile tests were conducted on samples of porcine rectus sheath to characterise the stress-stretch responses of the tissue. Under uniaxial tension, fibre direction samples failed on average at a stress of 4.5MPa at a stretch of 1.07 while cross-fibre samples failed at a stress of 1.6MPa under a stretch of 1.29. Under equi-biaxial tension, failure occurred at 1.6MPa with the fibre direction stretching to only 1.02 while the cross-fibre direction stretched to 1.13. Uniaxial and biaxial stress-stretch plots are presented allowing detailed modelling of the tissue either in silico or in a surrogate material. An FeBio computational model of the tissue is presented using a combination of an Ogden and an exponential power law model to represent the matrix and fibres respectively. The structural properties of porcine rectus sheath have been characterised and add to the small set of human data in the literature with which it may be possible to develop methods to reduce the incidence of incisional hernia development.

Identification of learning mechanisms in a wild meerkat population.

Directory of Open Access Journals (Sweden)

Will Hoppitt

Full Text Available Vigorous debates as to the evolutionary origins of culture remain unresolved due to an absence of methods for identifying learning mechanisms in natural populations. While laboratory experiments on captive animals have revealed evidence for a number of mechanisms, these may not necessarily reflect the processes typically operating in nature. We developed a novel method that allows social and asocial learning mechanisms to be determined in animal groups from the patterns of interaction with, and solving of, a task. We deployed it to analyse learning in groups of wild meerkats (Suricata suricatta presented with a novel foraging apparatus. We identify nine separate learning processes underlying the meerkats' foraging behaviour, in each case precisely quantifying their strength and duration, including local enhancement, emulation, and a hitherto unrecognized form of social learning, which we term 'observational perseverance'. Our analysis suggests a key factor underlying the stability of behavioural traditions is a high ratio of specific to generalized social learning effects. The approach has widespread potential as an ecologically valid tool to investigate learning mechanisms in natural groups of animals, including humans.

ALPHA-BETA SEPARATION PORTFOLIO STRATEGIES FOR ISLAMIC FINANCE

Directory of Open Access Journals (Sweden)

Valentyn Khokhlov

2016-11-01

Full Text Available The purpose of this paper is to develop a mathematical alpha-beta separation model that can be used to create a core-satellite portfolio management strategy that complies with the principles of Islamic finance. Methodology. Core-satellite portfolio construction methodology is used to implement the alpha-beta separation approach, where the core part of the portfolio is managed using the tracking error minimization strategy, and the satellite part of the portfolio is managed using the mean-variance optimization strategy. Results of the portfolio dynamics clearly show that a significant amount of value was created by alpha-beta separation. The typical alpha ranges from 4% to 5.7%. The most aggressive portfolio strategies that allow short positions in the satellite portfolio work best with frequent rebalancing and benefit from the active bets. Smoothing technique that was introduced to decrease the portfolio turnover and stabilize its composition works better when active bets are less efficient, particularly with less frequent rebalancing. The best risk-return combinations are achieved with modest (3% to 10% allocation of the total portfolio to the satellite, and the remaining part (90% to 97% being managed in order to minimize the tracking error. Practical implications. The alpha-beta separation framework suggested in this paper can be used to enhance the portfolio management techniques for the hedge funds that operate under tight restrictions, particularly under the Islamic finance principles. The mathematical models developed in this paper allow practical implementation of the alphabeta separation concept. Originality/value. While the idea of alpha-beta separation existed in hedge fund management before, there was no comprehensive mathematical model under it, so its implementation was based on the ad hoc approach. This paper introduces such a mathematical model and demonstrates how portfolio managers can create value for their clients using it.

Fracture Mechanisms of Zirconium Diboride Ultra-High Temperature Ceramics under Pulse Loading

Science.gov (United States)

Skripnyak, Vladimir V.; Bragov, Anatolii M.; Skripnyak, Vladimir A.; Lomunov, Andrei K.; Skripnyak, Evgeniya G.; Vaganova, Irina K.

2015-06-01

Mechanisms of failure in ultra-high temperature ceramics (UHTC) based on zirconium diboride under pulse loading were studied experimentally by the method of SHPB and theoretically using the multiscale simulation method. The obtained experimental and numerical data are evidence of the quasi-brittle fracture character of nanostructured zirconium diboride ceramics under compression and tension at high strain rates and the room temperatures. Damage of nanostructured porous zirconium diboride -based UHTC can be formed under stress pulse amplitude below the Hugoniot elastic limit. Fracture of nanostructured ultra-high temperature ceramics under pulse and shock-wave loadings is provided by fast processes of intercrystalline brittle fracture and relatively slow processes of quasi-brittle failure via growth and coalescence of microcracks. A decrease of the shear strength can be caused by nano-voids clusters in vicinity of triple junctions between ceramic matrix grains and ultrafine-grained ceramics. This research was supported by grants from ``The Tomsk State University Academic D.I. Mendeleev Fund Program'' and also N. I. Lobachevski State University of Nizhny Novgorod (Grant of post graduate mobility).

Parametric study of control mechanism of cortical bone remodeling under mechanical stimulus

Science.gov (United States)

Wang, Yanan; Qin, Qing-Hua

2010-03-01

The control mechanism of mechanical bone remodeling at cellular level was investigated by means of an extensive parametric study on a theoretical model described in this paper. From a perspective of control mechanism, it was found that there are several control mechanisms working simultaneously in bone remodeling which is a complex process. Typically, an extensive parametric study was carried out for investigating model parameter space related to cell differentiation and apoptosis which can describe the fundamental cell lineage behaviors. After analyzing all the combinations of 728 permutations in six model parameters, we have identified a small number of parameter combinations that can lead to physiologically realistic responses which are similar to theoretically idealized physiological responses. The results presented in the work enhanced our understanding on mechanical bone remodeling and the identified control mechanisms can help researchers to develop combined pharmacological-mechanical therapies to treat bone loss diseases such as osteoporosis.

Elucidating the molecular mechanisms underlying cellular response to biophysical cues using synthetic biology approaches

NARCIS (Netherlands)

Denning, Denise; Roos, Wouter H

2016-01-01

The use of synthetic surfaces and materials to influence and study cell behavior has vastly progressed our understanding of the underlying molecular mechanisms involved in cellular response to physicochemical and biophysical cues. Reconstituting cytoskeletal proteins and interfacing them with a

Separation of thorium from lanthanides by solvent extraction with ionizable crown ethers.

Science.gov (United States)

Du, H S; Wood, D J; Elshani, S; Wai, C M

1993-02-01

Thorium and the lanthanides are extracted by alpha-(sym-dibenzo-16-crown-5-oxy)acetic acid and its analogues in different pH ranges. At pH 4.5, Th is quantitatively extracted by the crown ether carboxylic acids into chloroform whereas the extraction of the lanthanides is negligible. Separation of Th from the lanthanides can be achieved by solvent extraction under this condition. The extraction does not require specific counteranions and is reversible with respect to pH. Trace amounts of Th in water can be quantitatively recovered using this extraction system for neutron activation analysis. The nature of the extracted Th complex and the mechanism of extraction are discussed.

First-principles predictions of structural, mechanical and electronic properties of βTiNb under high pressure

Science.gov (United States)

Wang, Z. P.; Fang, Q. H.; Li, J.; Liu, B.

2018-04-01

Structural, mechanical and electronic properties of βTiNb alloy under high pressure have been investigated based on the density functional theory (DFT). The dependences of dimensionless volume ratio, elastic constants, bulk modulus, Young's modulus, shear modulus, ductile/brittle, anisotropy and Poisson's ratio on applied pressure are all calculated successfully. The results reveal that βTiNb alloy is mechanically stable under pressure below 23.45 GPa, and the pressure-induced phase transformation could occur beyond this critical value. Meanwhile, the applied pressure can effectively promote the mechanical properties of βTiNb alloy, including the resistances to volume change, elastic deformation and shear deformation, as well as the material ductility and metallicity. Furthermore, the calculated electronic structures testify that βTiNb alloy performs the metallicity and the higher pressure reduces the structural stability of unit cell.

Underlying mechanisms and the evolving influence of diet

DEFF Research Database (Denmark)

Larsen, Lesli Hingstrup

2012-01-01

Obesity is determined by both genetic and environmental factors. Since 2007, 52 genes have been associated with obesity and obesity-related measurements in genome-wide association studies (GWAS), among these the fat and obesity-associated gene (FTO). Despite the success in identifying genes predi...... and the microbiome that can be modified by diet, and by genotype, adding to the complexity of determining the contributors to obesity....... has been shown to attenuate the effect of FTO on obesity. Several studies have examined gene-diet interactions in relation to obesity, but only a few suggestive interactions have been identified. This is most probably due to small effect sizes of the interactions and thereby a demand for large samples...... to increased risk of developing obesity. Recently, the intestinal microbiome, the collected genome of the bacteria, also has been associated with obesity and with specific dietary profiles. The underlying mechanisms determining the susceptibility to obesity do not only include the genome but also the epigenome...

Mechanical processing of bast fibres: The occurrence of damage and its effect on fibre structure

DEFF Research Database (Denmark)

Hänninen, Tuomas; Thygesen, Anders; Mehmood, Shahid

2012-01-01

Currently, separation processes used for natural fibres for composite reinforcing textiles cause a significant amount of damage to the fibres. Microscopic analysis showed that industrially processed flax (Linum usitassimium L.) fibres contained significantly more defects than green or retted ones...... to heterogeneous reactivity. Analogous findings were observed in hemp (Cannabis sativa L.) fibre damaged in the laboratory under controlled conditions, emphasising the need to develop extraction and separation processes that minimise mechanical damage to the fibres....

Optimal Contract Design for Cooperative Relay Incentive Mechanism under Moral Hazard

Directory of Open Access Journals (Sweden)

Nan Zhao

2015-01-01

Full Text Available Cooperative relay can effectively improve spectrum efficiency by exploiting the spatial diversity in the wireless networks. However, wireless nodes may acquire different network information with various users’ location and mobility, channels’ conditions, and other factors, which results in asymmetric information between the source and the relay nodes (RNs. In this paper, the relay incentive mechanism between relay nodes and the source is investigated under the asymmetric information. By modelling multiuser cooperative relay as a labour market, a contract model with moral hazard for relay incentive is proposed. To effectively incentivize the potential RNs to participate in cooperative relay, the optimization problems are formulated to maximize the source’s utility while meeting the feasible conditions under both symmetric and asymmetric information scenarios. Numerical simulation results demonstrate the effectiveness of the proposed contract design scheme for cooperative relay.

An investigation of the mechanical behavior of initially curved microplates under electrostatic actuation

KAUST Repository

Saghir, Shahid

2018-03-28

In this article, we investigate the mechanical behavior of initially curved microplates under electrostatic actuation. Microplates are essential components of many Micro-Electro-Mechanical System devices; however, they commonly undergo an initial curvature imperfection, due to the microfabrication process. Initial curvature imperfection significantly affects the mechanical behavior of microplates. In this work, we derive a dynamic analogue of the von Kármán governing equation for such plates. These equations are then used to develop a reduced order model based on the Galerkin procedure to simulate the static and dynamic behavior of the microplate. Two profiles of initial curvature commonly encountered in microfabricated structures are considered, where one assumes a variation in shape along one dimension of the plate only (cylindrical bending shape) while the other assumes a variation in shape along both dimensions of the plate. Their effects on both the static and dynamic responses of the microplates are examined and compared. We validate the reduced order model by comparing the calculated static behavior and the fundamental natural frequency with those computed by a finite element model over a range of the initial plate rise. The static behavior of the microplate is investigated when varying the DC voltage. Then, the dynamic behavior of the microplate is examined under the application of a harmonic AC voltage superimposed to a DC voltage.

Phase separation and large deviations of lattice active matter

Science.gov (United States)

Whitelam, Stephen; Klymko, Katherine; Mandal, Dibyendu

2018-04-01

Off-lattice active Brownian particles form clusters and undergo phase separation even in the absence of attractions or velocity-alignment mechanisms. Arguments that explain this phenomenon appeal only to the ability of particles to move persistently in a direction that fluctuates, but existing lattice models of hard particles that account for this behavior do not exhibit phase separation. Here we present a lattice model of active matter that exhibits motility-induced phase separation in the absence of velocity alignment. Using direct and rare-event sampling of dynamical trajectories, we show that clustering and phase separation are accompanied by pronounced fluctuations of static and dynamic order parameters. This model provides a complement to off-lattice models for the study of motility-induced phase separation.

Evaluating Public Plantation and Community Planted Forests under the CDM and REDD+ Mechanism for Carbon Stock in Nepal

Directory of Open Access Journals (Sweden)

Ram Asheshwar MANDAL

2013-09-01

Full Text Available Public plantations (PPs and Community planted forests (CPFs are inimitable types of participatory forest management practices in Nepal, but their eligibility issues under the framework of clean development mechanism (CDM and reducing emission from the deforestation and forest degradation mechanism (REDD+ are not evaluated. So, to explore the management system of PP and CPF, we compared forest carbon stocks in plantations and evaluated these plantations under these mechanisms as objectives of this research. The relevant documents were revised and altogether 55 samples were collected from Shreepur, Banauta and Bisbity PPs and Sita, Ramnagar and Jogikuti CPFs, in Mahottary district, Nepal. The equation of Chave et al was used to calculate the biomass, which was further converted into carbon. Meanwhile, management practices were evaluated under the framework of CDM and REDD+. The PPs are public land managed, especially by disadvantaged communities, while CPFs are the patches of national forest managed by users. The variation in carbon stock was found to be highest (148.89 ton ha-1 in Sita CPF and lowest (30.34 ton ha-1 in Bisbitty PP. In fact, it is difficult to certify plantations under CDM, due to its complexity, but they can easily be candidate to the REDD+ mechanism, if they are bundled with large forest blocks.

Underlying Mechanisms of Tinnitus: Review and Clinical Implications

Science.gov (United States)

Henry, James A.; Roberts, Larry E.; Caspary, Donald M.; Theodoroff, Sarah M.; Salvi, Richard J.

2016-01-01

Background The study of tinnitus mechanisms has increased tenfold in the last decade. The common denominator for all of these studies is the goal of elucidating the underlying neural mechanisms of tinnitus with the ultimate purpose of finding a cure. While these basic science findings may not be immediately applicable to the clinician who works directly with patients to assist them in managing their reactions to tinnitus, a clear understanding of these findings is needed to develop the most effective procedures for alleviating tinnitus. Purpose The goal of this review is to provide audiologists and other health-care professionals with a basic understanding of the neurophysiological changes in the auditory system likely to be responsible for tinnitus. Results It is increasingly clear that tinnitus is a pathology involving neuroplastic changes in central auditory structures that take place when the brain is deprived of its normal input by pathology in the cochlea. Cochlear pathology is not always expressed in the audiogram but may be detected by more sensitive measures. Neural changes can occur at the level of synapses between inner hair cells and the auditory nerve and within multiple levels of the central auditory pathway. Long-term maintenance of tinnitus is likely a function of a complex network of structures involving central auditory and nonauditory systems. Conclusions Patients often have expectations that a treatment exists to cure their tinnitus. They should be made aware that research is increasing to discover such a cure and that their reactions to tinnitus can be mitigated through the use of evidence-based behavioral interventions. PMID:24622858

On the efficiency of a fluid-fluid centrifugal separation

International Nuclear Information System (INIS)

Apazidis, N.

1984-05-01

Efficiency of a separation process of two immiscible incompressible fluids of different densities occuring under the influence of a combined centrifugal and gravitational force field is investigated. The analysis is based on the set of equations for a rotating two-phase flow of a mixture as presented by Greenspan (1983). The geometry of the separation process is considered and the total flow of the separated phases evaluated. (author)

Simulative technology for auxiliary fuel tank separation in a wind tunnel

Directory of Open Access Journals (Sweden)

Ma Xin

2016-06-01

Full Text Available In this paper, we propose a simulative experimental system in wind tunnel conditions for the separation of auxiliary fuel tanks from an aircraft. The experimental system consists of a simulative release mechanism, a scaled model and a pose measuring system. A new release mechanism was designed to ensure stability of the separation. Scaled models of the auxiliary fuel tank were designed and their moment of inertia was adjusted by installing counterweights inside the model. Pose parameters of the scaled model were measured and calculated by a binocular vision system. Additionally, in order to achieve high brightness and high signal-to-noise ratio of the images in the dark enclosed wind tunnel, a new high-speed image acquisition method based on miniature self-emitting units was presented. Accuracy of the pose measurement system and repeatability of the separation mechanism were verified in the laboratory. Results show that the position precision of the pose measurement system can reach 0.1 mm, the precision of the pitch and yaw angles is less than 0.1° and that of the roll angle can be up to 0.3°. Besides, repeatability errors of models’ velocity and angular velocity controlled by the release mechanism remain small, satisfying the measurement requirements. Finally, experiments for the separation of auxiliary fuel tanks were conducted in the laboratory.