Effects of Particle Size on the Shear Behavior of Coarse Grained Soils Reinforced with Geogrid

Directory of Open Access Journals (Sweden)

Daehyeon Kim

2014-02-01

Full Text Available In order to design civil structures that are supported by soils, the shear strength parameters of soils are required. Due to the large particle size of coarse-grained soils, large direct shear tests should be performed. In this study, large direct shear tests on three types of coarse grained soils (4.5 mm, 7.9 mm, and 15.9 mm were performed to evaluate the effects of particle size on the shear behavior of coarse grained soils with/without geogrid reinforcements. Based on the direct shear test results, it was found that, in the case of no-reinforcement, the larger the maximum particle size became, the larger the friction angle was. Compared with the no-reinforcement case, the cases reinforced with either soft geogrid or stiff geogrid have smaller friction angles. The cohesion of the soil reinforced with stiff geogrid was larger than that of the soil reinforced with soft geogrid. The difference in the shear strength occurs because the case with a stiff geogrid has more soil to geogrid contact area, leading to the reduction in interlocking between soil particles.

Accelerator-Based Irradiation Creep of Pyrolytic Carbon Used in TRISO Fuel Particles for the (VHTR) Very High Temperature Reactors

International Nuclear Information System (INIS)

Wang, Lumin; Was, Gary

2010-01-01

Pyrolytic carbon (PyC) is one of the important structural materials in the TRISO fuel particles which will be used in the next generation of gas-cooled very-high-temperature reactors (VHTR). When the TRISO particles are under irradiation at high temperatures, creep of the PyC layers may cause radial cracking leading to catastrophic particle failure. Therefore, a fundamental understanding of the creep behavior of PyC during irradiation is required to predict the overall fuel performance.

Understanding the polarization signal of spherical particles for microwave limb radiances

International Nuclear Information System (INIS)

Teichmann, C.; Buehler, S.A.; Emde, C.

2006-01-01

This paper presents a simple conceptual model to explain that even spherical scatterers lead to a polarization difference signal for microwave limb radiances. The conceptual model relates the polarization difference measured by a limb-looking sensor situated inside a cloud with the anisotropy of the radiation. In the simulations, it was assumed that the cloud consists of spherical ice particles with a radius of 68.5μm which were situated between 10.6 and 12.3km altitude. The frequencies 318 and 500GHz were considered. The results of the conceptual model were compared to the results of the fully polarized scattering model ARTS-1-1. The comparison showed a good qualitative agreement. The polarization difference decreases inside the cloud with increasing height and changes sign. This behavior can be related to a different amount of radiation coming from the atmosphere above and below the cloud, compared to the amount of radiation coming from the sides. The sign of polarization difference of the scattered radiation is opposite for these two radiation sources

Effects of Quartz Particle Size and Sucrose Addition on Melting Behavior of a Melter Feed for High-Level Waste Glass

International Nuclear Information System (INIS)

Marcial, Jose; Hrma, Pavel R.; Schweiger, Michael J.; Swearingen, Kevin J.; Tegrotenhuis, Nathan E.; Henager, Samuel H.

2010-01-01

The behavior of melter feed (a mixture of nuclear waste and glass-forming additives) during waste-glass processing has a significant impact on the rate of the vitrification process. We studied the effects of silica particle size and sucrose addition on the volumetric expansion (foaming) of a high-alumina feed and the rate of dissolution of silica particles in feed samples heated at 5 C/min up to 1200 C. The initial size of quartz particles in feed ranged from 5 to 195 (micro)m. The fraction of the sucrose added ranged from 0 to 0.20 g per g glass. Extensive foaming occurred only in feeds with 5-(micro)m quartz particles; particles (ge) 150 (micro)m formed clusters. Particles of 5 (micro)m completely dissolved by 900 C whereas particles (ge) 150 (micro)m did not fully dissolve even when the temperature reached 1200 C. Sucrose addition had virtually zero impact on both foaming and the dissolution of silica particles.

Particle behavior in an ECR plasma etch tool

International Nuclear Information System (INIS)

Blain, M.G.; Tipton, G.D.; Holber, W.M.; Westerfield, P.L.; Maxwell, K.L.

1993-01-01

Sources of particles in a close-coupled electron cyclotron resonance (ECR) polysilicon plasma etch source include flaking of films deposited on chamber surfaces, and shedding of material from electrostatic wafer chucks. A large, episodic increase in the number of particles added to a wafer in a clean system is observed more frequently for a plasma-on than for a gas-only source condition. For polymer forming process conditions, particles were added to wafers by a polymer film which was observed to fracture and flake away from chamber surfaces. The presence of a plasma, especially when rf bias is applied to the wafer, caused more particles to be ejected from the walls and added to wafers than the gas-only condition; however, no significant influence was observed with different microwave powers. A study of effect of electrode temperatures on particles added showed that thermophoretic forces are not significant for this ECR configuration. Particles originating from the electrostatic chuck were observed to be deposited on wafers in much larger numbers in the presence of the plasma as compared to gas-only conditions

On the transport, segregation, and dispersion of heavy and light particles interacting with rising thermal plumes

Science.gov (United States)

Lappa, Marcello

2018-03-01

A systematic numerical analysis is carried out on the multiplicity of patterns produced by inertial particles dispersed in a fluid and localized gravitational convection developing in the form of a rising thermal plume. In particular, specific numerical examples are presented to provide inputs for an increased understanding of the underlying flow-particle interaction mechanisms and cause-and-effect relationships. A rich spectrum of convective dynamics is obtained at the relatively high value of the considered Rayleigh number (Ra = 108), which naturally allows the investigation of several intriguing effects (including, but not limited to, particle interaction with plume jet, associated vortices, shear instabilities, and symmetry breaking phenomena). An important degree of freedom is introduced in the problem by changing the particle viscous drag through proper tuning of the related Stokes number (St). Similarly, inertia and weight of solid matter are varied parametrically by performing numerical simulations for both light and heavy particles at different values of the Froude number. This framework lets us identify the average behavior of particles by revealing the mean evolution. We connect such statistics to the behavior of the temporally evolving thermal plume, giving deeper insights into the particle transport mechanisms and associated dissipative dynamics.

The effect of conditioning by permanganate on the dissolution behavior of stellite particles in organic complexing acid medium

International Nuclear Information System (INIS)

Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Sukumar, A.A.; Raju, V.S.; Velmurugan, S.; Narasimhan, S.V.

2004-01-01

Radioactive hotspots found either in the primary heat transport circuit or auxiliary circuits of nuclear reactors are mainly due to particles containing activated cobalt. The main source of these particles are stellite alloys that are rich in cobalt and are used in primary cooling circuits in valves, pumps, etc. Due to either mechanical erosion or erosion coupled with corrosion under flow conditions (known as tribocorrosion), these stellite particles are released into the system. They are then activated by neutron absorption in the reactor core before being deposited on out-of-core surfaces, causing radiation exposure problems. In this paper, the possibility of dissolving stellite particles by using an oxidation-complexation process has been explored. Permanganate based reagents were evaluated for their efficiency in conditioning the stellite particles for their dissolution with organic acids. Permanganic acid was found to be the superior conditioning agent. Two alloys of stellite, viz. stellites no. 3 and no. 6, were studied with respect to their dissolution behavior

Signature of intermittent behavior in the emission spectra of target associated particles from 84Kr-AgBr interactions at 0.95 GeV/A

International Nuclear Information System (INIS)

Bhattacharjee, B.

2005-01-01

Intermittency and fractal behavior have been studied for emission spectra of target associated fast and slow particles from 84 Kr-AgBr interactions at 0.95 GeV/A. Intermittent behavior is observed for both knocked out and slow target fragments. In both the cases anomalous dimensions are seen to increase with the order of moments thereby indicating the association of multifractility with production mechanism of both fast and slow target associated particles

Elementary particles and particle interactions

International Nuclear Information System (INIS)

Bethge, K.; Schroeder, U.E.

1986-01-01

This book is a textbook for an introductory course of elementary particle physics. After a general introduction the symmetry principles governing the interactions of elementary particles are discussed. Then the phenomenology of the electroweak and strong interactions are described together with a short introduction to the Weinberg-Salam theory respectively to quantum chromodynamics. Finally a short outlook is given to grand unification with special regards to SU(5) and cosmology in the framework of the current understanding of the fundamental principles of nature. In the appendix is a table of particle properties and physical constants. (HSI) [de

Acid hydrolysis and molecular density of phytoglycogen and liver glycogen helps understand the bonding in glycogen α (composite particles.

Directory of Open Access Journals (Sweden)

Prudence O Powell

Full Text Available Phytoglycogen (from certain mutant plants and animal glycogen are highly branched glucose polymers with similarities in structural features and molecular size range. Both appear to form composite α particles from smaller β particles. The molecular size distribution of liver glycogen is bimodal, with distinct α and β components, while that of phytoglycogen is monomodal. This study aims to enhance our understanding of the nature of the link between liver-glycogen β particles resulting in the formation of large α particles. It examines the time evolution of the size distribution of these molecules during acid hydrolysis, and the size dependence of the molecular density of both glucans. The monomodal distribution of phytoglycogen decreases uniformly in time with hydrolysis, while with glycogen, the large particles degrade significantly more quickly. The size dependence of the molecular density shows qualitatively different shapes for these two types of molecules. The data, combined with a quantitative model for the evolution of the distribution during degradation, suggest that the bonding between β into α particles is different between phytoglycogen and liver glycogen, with the formation of a glycosidic linkage for phytoglycogen and a covalent or strong non-covalent linkage, most probably involving a protein, for glycogen as most likely. This finding is of importance for diabetes, where α-particle structure is impaired.

Acid Hydrolysis and Molecular Density of Phytoglycogen and Liver Glycogen Helps Understand the Bonding in Glycogen α (Composite) Particles

Science.gov (United States)

Powell, Prudence O.; Sullivan, Mitchell A.; Sheehy, Joshua J.; Schulz, Benjamin L.; Warren, Frederick J.; Gilbert, Robert G.

2015-01-01

Phytoglycogen (from certain mutant plants) and animal glycogen are highly branched glucose polymers with similarities in structural features and molecular size range. Both appear to form composite α particles from smaller β particles. The molecular size distribution of liver glycogen is bimodal, with distinct α and β components, while that of phytoglycogen is monomodal. This study aims to enhance our understanding of the nature of the link between liver-glycogen β particles resulting in the formation of large α particles. It examines the time evolution of the size distribution of these molecules during acid hydrolysis, and the size dependence of the molecular density of both glucans. The monomodal distribution of phytoglycogen decreases uniformly in time with hydrolysis, while with glycogen, the large particles degrade significantly more quickly. The size dependence of the molecular density shows qualitatively different shapes for these two types of molecules. The data, combined with a quantitative model for the evolution of the distribution during degradation, suggest that the bonding between β into α particles is different between phytoglycogen and liver glycogen, with the formation of a glycosidic linkage for phytoglycogen and a covalent or strong non-covalent linkage, most probably involving a protein, for glycogen as most likely. This finding is of importance for diabetes, where α-particle structure is impaired. PMID:25799321

Modified resistivity-strain behavior through the incorporation of metallic particles in conductive polymer composite fibers containing carbon nanotubes

NARCIS (Netherlands)

Lin, L.; Deng, H.; Gao, X.; Zhang, S.M.; Bilotti, E.; Peijs, A.A.J.M.; Fu, Q.

2013-01-01

Eutectic metal particles and carbon nanotubes are incorporated into a thermoplastic polyurethane matrix through a simple but efficient method, melt compounding, to tune the resistivity-strain behavior of conductive polymer composite (CPC) fibers. Such a combination of conductive fillers is rarely

Influence of Sludge Particles on the Fatigue Behavior of Al-Si-Cu Secondary Aluminium Casting Alloys

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Lorella Ceschini

2018-04-01

Full Text Available Al-Si-Cu alloys are the most widely used materials for high-pressure die casting processes. In such alloys, Fe content is generally high to avoid die soldering issues, but it is considered an impurity since it generates acicular intermetallics (β-Fe which are detrimental to the mechanical behavior of the alloys. Mn and Cr may act as modifiers, leading to the formation of other Fe-bearing particles which are characterized by less harmful morphologies, and which tend to settle on the bottom of furnaces and crucibles (usually referred to as sludge. This work is aimed at evaluating the influence of sludge intermetallics on the fatigue behavior of A380 Al-Si-Cu alloy. Four alloys were produced by adding different Fe, Mn and Cr contents to A380 alloy; samples were remelted by directional solidification equipment to obtain a fixed secondary dendrite arm spacing (SDAS value (~10 μm, then subjected to hot isostatic pressing (HIP. Rotating bending fatigue tests showed that, at room temperature, sludge particles play a detrimental role on fatigue behavior of T6 alloys, diminishing fatigue strength. At elevated temperatures (200 °C and after overaging, the influence of sludge is less relevant, probably due to a softening of the α-Al matrix and a reduction of stress concentration related to Fe-bearing intermetallics.

Contactless grasp of a magnetic particle in a fluid and its application to quantifications of forces affecting its behavior

International Nuclear Information System (INIS)

Tokura, S.; Hara, M.; Kawaguchi, N.; Amemiya, N.

2014-01-01

In this study, the contactless grasp of a magnetic particle suspended in a fluid at rest or in motion by coil current control, and a method for estimating these forces quantitatively were developed. Four electromagnets were used to apply magnetic fields to magnetic ferrite particles (diameter, 300 nm–300 µm) in a fluid in a vessel. Particle-tracking velocimetry with high-speed image processing was used to visualize the behavior of the magnetic particles in the fluid. In addition, contactless grasp of a magnetic particle using the feedback control was accomplished. Furthermore, by making the magnetic force and the resultant force of the other forces affecting a magnetic particle be in balance, the vertical and horizontal forces affecting the minute magnetic particle, such as the viscous force or the magnetic force between magnetized particles, could be estimated quantitatively from the current in the coil of each electromagnet, without any physical contact with the particle itself. These results constitute useful information for studies on the issues in the handling of micro- or nano-particles. - Highlights: • Four electromagnets are used to apply magnetic field to magnetic ferrite particles. • Motion of magnetic particles suspended in a resting or flowing fluid is visualized. • Contactless grasp of a magnetic particle using feedback control was accomplished. • Vertical and horizontal forces affecting a particle can be estimated quantitatively. • Force between magnetized particles which approach to each other was measured

Effect of Particle Size on Mechanical Properties of Sawdust-High Density Polyethylene Composites under Various Strain Rates

Directory of Open Access Journals (Sweden)

Haliza Jaya

2016-06-01

Full Text Available There is a need to understand the effect of wood particle size, as it affects the characteristics of wood-based composites. This study considers the effect of wood particle size relative to the dynamic behavior of wood composites. The compression Split Hopkinson Pressure Bar (SHPB was introduced to execute dynamic compression testing at the strain rate of 650 s-1, 900 s-1, and 1100 s-1, whereas a conventional universal testing machine (UTM was used to perform static compression testing at the strain rate of 0.1 s-1, 0.01 s-1, and 0.001 s-1 for four different particle sizes (63 µm, 125 µm, 250 µm, and 500 µm. The results showed that mechanical properties of composites were positively affected by the particle sizes, where the smallest particle size gave the highest values compared to the others. Moreover, the particle size also affected the rate sensitivity and the thermal activation volume of sawdust/HDPE, where smaller particles resulted in lower rate sensitivity. For the post-damage analysis, the applied strain rates influenced deformation behavior differently for all particle sizes of the specimens. In a fractographic analysis under dynamic loading, the composites with large particles experienced severe catastrophic deformation and damages compared to the smaller particles.

A Generalized Slave-Particle Method

Science.gov (United States)

Georgescu, Alexandru Bogdan; Ismail-Beigi, Sohrab

2015-03-01

Two slave-particle methods, namely the slave-rotor and the slave-spin approaches, have been of recent interest in the computational correlated electron community. Both methods solve Hubbard-type models and go beyond the single-particle approximations by describing aspects of correlated electron behavior in a computationally efficient manner. We present a generalized slave-particle formalism that connects the the two while reproducing the results of each method in the appropriate limit. The framework automatically corrects the problematic small U behavior of the slave-rotor approach while reproducing its behavior in situations where it has been found physically relevant (e.g., for nickelate heterostructures). This work is supported by the National Science Foundation through Grant MRSEC NSF DMR-1119826.

Effect of Ti and C particle sizes on reaction behavior of thermal explosion reaction of Cu−Ti−C system under Ar and air atmospheres

Energy Technology Data Exchange (ETDEWEB)

Liang, Yunhong; Zhao, Qian; Li, Xiujuan; Zhang, Zhihui, E-mail: zhzh@jlu.edu.cn; Ren, Luquan

2016-09-15

The thermal explosion (TE) reaction behavior of Cu−Ti−C systems with different Ti and C particle sizes was investigated under air and Ar atmospheres. It was found that increasing the Ti and C particle sizes leads to higher ignition temperatures under both atmospheres and that the maximum combustion temperature decreases with increasing C particle size. The TE reaction is much easier to activate (i.e., it has a lower ignition temperature) in air because of the heat released from Ti oxidation and nitridation and Cu oxidation reactions on the Cu−Ti−C compact surface. TiC ceramic particles are successfully prepared in the bulk Cu−Ti−C compacts under both air and Ar atmospheres through a dissolution-diffusion-precipitation mechanism. Differential thermal and thermodynamic analyses show that the TE reaction ignition process in air is mainly controlled by the Ti particle size. - Highlights: • Variation of Ti and C particle sizes affects thermal reaction (TE) behaviors. • Ignition temperature under air is much lower than that under Ar atmosphere. • Heat of oxidation and nitridation reactions reduces ignition temperature under air.

Understanding Electronic Word of Behavior

DEFF Research Database (Denmark)

Kunst, Katrine; Vatrapu, Ravi

2018-01-01

The widespread digitization of consumers’ daily lives entails a plethora of digital traces of consumers’ behaviors. These traces can be turned into meaningful communicative and observable content by the services that possess the trace data. While extant research has empirically showed this to have...... a significant impact on consumer choices we argue that the phenomenon is undertheorized. In this theoretical paper, we conceptualize this kind of observable behavior-based information as ‘Electronic Word of Behavior’ (eWOB) and define it as “published accounts of behavior, based on the unobservable digital...... traces of consumers’ behaviors”. We characterize eWOB as an instantiation of Digital Trace Data and situate it within the established concepts of Social Interactions and Electronic Word of Mouth (eWOM). By drawing on extant empirical research and constructs from Digital Trace Data, Social Interactions...

Microstructure of Semi-Solid Billets Produced by Electromagnetic Stirring and Behavior of Primary Particles during the Indirect Forming Process

Directory of Open Access Journals (Sweden)

Chul Kyu Jin

2018-04-01

Full Text Available An A356 alloy semi-solid billet was fabricated using electromagnetic stirring. After inserting the semi-solid billet into an indirect die, a thin plate of 1.2 mm thickness was fabricated by applying compression. The microstructure of the semi-solid billets fabricated in various stirring conditions (solid fraction and stirring force were analyzed. The deformation and behavior of the primary α-Al particles were analyzed for various parameters (solid fraction, die friction, compression rate, and compression pressure. In the stirred billets, a globular structure was dominant, while a dendrite structure was dominant in the unstirred billets. As the solid fraction decreased and the stirring current increased, the equivalent diameter and roundness of the primary α-Al particles decreased. The primary α-Al particle sizes were reduced as the compressing velocity increased, while a greater number of particles could move as the compressing pressure increased. As the path over which the motion occurred became smoother, the fluidity of the particles improved. Under compression, bonded primary α-Al particles became separated into individual particles again, as the bonds were broken. As wearing caused by friction and collisions between the particles during this motion occurred, the particle sizes were reduced, and the particle shapes become increasingly spheroid.

Simulating Sand Behavior through Terrain Subdivision and Particle Refinement

Science.gov (United States)

Clothier, M.

2013-12-01

Advances in computer graphics, GPUs, and parallel processing hardware have provided researchers with new methods to visualize scientific data. In fact, these advances have spurred new research opportunities between computer graphics and other disciplines, such as Earth sciences. Through collaboration, Earth and planetary scientists have benefited by using these advances in hardware technology to process large amounts of data for visualization and analysis. At Oregon State University, we are collaborating with the Oregon Space Grant and IGERT Ecosystem Informatics programs to investigate techniques for simulating the behavior of sand. In addition, we have also been collaborating with the Jet Propulsion Laboratory's DARTS Lab to exchange ideas on our research. The DARTS Lab specializes in the simulation of planetary vehicles, such as the Mars rovers. One aspect of their work is testing these vehicles in a virtual "sand box" to test their performance in different environments. Our research builds upon this idea to create a sand simulation framework to allow for more complex and diverse environments. As a basis for our framework, we have focused on planetary environments, such as the harsh, sandy regions on Mars. To evaluate our framework, we have used simulated planetary vehicles, such as a rover, to gain insight into the performance and interaction between the surface sand and the vehicle. Unfortunately, simulating the vast number of individual sand particles and their interaction with each other has been a computationally complex problem in the past. However, through the use of high-performance computing, we have developed a technique to subdivide physically active terrain regions across a large landscape. To achieve this, we only subdivide terrain regions where sand particles are actively participating with another object or force, such as a rover wheel. This is similar to a Level of Detail (LOD) technique, except that the density of subdivisions are determined by

Mathematical model and computer code for coated particles performance at normal operating conditions

International Nuclear Information System (INIS)

Golubev, I.; Kadarmetov, I.; Makarov, V.

2002-01-01

Computer modeling of thermo-mechanical behavior of coated particles during operating both at normal and off-normal conditions has a very significant role particularly on a stage of new reactors development. In Russia a big experience has been accumulated on fabrication and reactor tests of CP and fuel elements with UO 2 kernels. However, this experience cannot be using in full volume for development of a new reactor installation GT-MHR. This is due to very deep burn-up of the fuel based on plutonium oxide (up to 70% fima). Therefore the mathematical modeling of CP thermal-mechanical behavior and failure prediction becomes particularly important. The authors have a clean understanding that serviceability of fuel with high burn-ups are defined not only by thermo-mechanics, but also by structured changes in coating materials, thermodynamics of chemical processes, 'amoeba-effect', formation CO etc. In the report the first steps of development of integrate code for numerical modeling of coated particles behavior and some calculating results concerning the influence of various design parameters on fuel coated particles endurance for GT-MHR normal operating conditions are submitted. A failure model is developed to predict the fraction of TRISO-coated particles. In this model it is assumed that the failure of CP depends not only on probability of SiC-layer fracture but also on the PyC-layers damage. The coated particle is considered as a uniform design. (author)

Influence of Nickel Particle Reinforcement on Cyclic Fatigue and Final Fracture Behavior of a Magnesium Alloy Composite

Directory of Open Access Journals (Sweden)

Manoj Gupta

2012-06-01

Full Text Available The microstructure, tensile properties, cyclic stress amplitude fatigue response and final fracture behavior of a magnesium alloy, denoted as AZ31, discontinuously reinforced with nano-particulates of aluminum oxide and micron size nickel particles is presented and discussed. The tensile properties, high cycle fatigue and final fracture behavior of the discontinuously reinforced magnesium alloy are compared with the unreinforced counterpart (AZ31. The elastic modulus and yield strength of the dual particle reinforced magnesium alloy is marginally higher than of the unreinforced counterpart. However, the tensile strength of the composite is lower than the monolithic counterpart. The ductility quantified by elongation to failure over 0.5 inch (12.7 mm gage length of the test specimen showed minimal difference while the reduction in specimen cross-section area of the composite is higher than that of the monolithic counterpart. At the microscopic level, cyclic fatigue fractures of both the composite and the monolithic alloy clearly revealed features indicative of the occurrence of locally ductile and brittle mechanisms. Over the range of maximum stress and at two different load ratios the cyclic fatigue resistance of the magnesium alloy composite is superior to the monolithic counterpart. The mechanisms responsible for improved cyclic fatigue life and resultant fracture behavior of the composite microstructure are highlighted.

Computational Intelligence-Assisted Understanding of Nature-Inspired Superhydrophobic Behavior.

Science.gov (United States)

Zhang, Xia; Ding, Bei; Cheng, Ran; Dixon, Sebastian C; Lu, Yao

2018-01-01

In recent years, state-of-the-art computational modeling of physical and chemical systems has shown itself to be an invaluable resource in the prediction of the properties and behavior of functional materials. However, construction of a useful computational model for novel systems in both academic and industrial contexts often requires a great depth of physicochemical theory and/or a wealth of empirical data, and a shortage in the availability of either frustrates the modeling process. In this work, computational intelligence is instead used, including artificial neural networks and evolutionary computation, to enhance our understanding of nature-inspired superhydrophobic behavior. The relationships between experimental parameters (water droplet volume, weight percentage of nanoparticles used in the synthesis of the polymer composite, and distance separating the superhydrophobic surface and the pendant water droplet in adhesive force measurements) and multiple objectives (water droplet contact angle, sliding angle, and adhesive force) are built and weighted. The obtained optimal parameters are consistent with the experimental observations. This new approach to materials modeling has great potential to be applied more generally to aid design, fabrication, and optimization for myriad functional materials.

High temperature oxidation behavior of SiC coating in TRISO coated particles

International Nuclear Information System (INIS)

Liu, Rongzheng; Liu, Bing; Zhang, Kaihong; Liu, Malin; Shao, Youlin; Tang, Chunhe

2014-01-01

Highlights: • High temperature oxidation tests of SiC coating in TRISO particles were carried out. • The dynamic oxidation process was established. • Oxidation mechanisms were proposed. • The existence of silicon oxycarbides at the SiO 2 /SiC interface was demonstrated. • Carbon was detected at the interface at high temperatures and long oxidation time. - Abstract: High temperature oxidation behavior of SiC coatings in tristructural-isotropic (TRISO) coated particles is crucial to the in-pile safety of fuel particles for a high temperature gas cooled reactor (HTGR). The postulated accident condition of air ingress was taken into account in evaluating the reliability of the SiC layer. Oxidation tests of SiC coatings were carried out in the ranges of temperature between 800 and 1600 °C and time between 1 and 48 h in air atmosphere. Based on the microstructure evolution of the oxide layer, the mechanisms and kinetics of the oxidation process were proposed. The existence of silicon oxycarbides (SiO x C y ) at the SiO 2 /SiC interface was demonstrated by X-ray photospectroscopy (XPS) analysis. Carbon was detected by Raman spectroscopy at the interface under conditions of very high temperatures and long oxidation time. From oxidation kinetics calculation, activation energies were 145 kJ/mol and 352 kJ/mol for the temperature ranges of 1200–1500 °C and 1550–1600 °C, respectively

Understanding Licensing Behavior

DEFF Research Database (Denmark)

Cabaleiro, Goretti; Moreira, Solon; Reichstein, Toke

The potential for rent dissipation has been argued to be the main cause of firms? licensing out behavior being stifled.However, this aspect has been scarcely studied empirically. We draw on rent dissipation arguments, and hypothesize that firms suffering from the not-invented-here (NIH) syndrome......, firms in competitive product markets, and firms that have incurred substantial sunk cost are associated with lower rates of technology out-licensing. We also posit that sunk costs negatively moderate the relationship between competition in the licensor?s product market, and licensing rate. We test our...

Averaging Gone Wrong: Using Time-Aware Analyses to Better Understand Behavior

OpenAIRE

Barbosa, Samuel; Cosley, Dan; Sharma, Amit; Cesar-Jr, Roberto M.

2016-01-01

Online communities provide a fertile ground for analyzing people's behavior and improving our understanding of social processes. Because both people and communities change over time, we argue that analyses of these communities that take time into account will lead to deeper and more accurate results. Using Reddit as an example, we study the evolution of users based on comment and submission data from 2007 to 2014. Even using one of the simplest temporal differences between users---yearly coho...

Motion Segments Decomposition of RGB-D Sequences for Human Behavior Understanding

OpenAIRE

Devanne , Maxime; Berretti , Stefano; Pala , Pietro; Wannous , Hazem; Daoudi , Mohamed; Bimbo , Alberto ,

2017-01-01

International audience; In this paper, we propose a framework for analyzing and understanding human behavior from depth videos. The proposed solution first employs shape analysis of the human pose across time to decompose the full motion into short temporal segments representing elementary motions. Then, each segment is characterized by human motion and depth appearance around hand joints to describe the change in pose of the body and the interaction with objects. Finally , the sequence of te...

Solid Particle Erosion of Date Palm Leaf Fiber Reinforced Polyvinyl Alcohol Composites

Directory of Open Access Journals (Sweden)

Jyoti R. Mohanty

2014-01-01

Full Text Available Solid particle erosion behavior of short date palm leaf (DPL fiber reinforced polyvinyl alcohol (PVA composite has been studied using silica sand particles (200 ± 50 μm as an erodent at different impingement angles (15–90° and impact velocities (48–109 m/s. The influence of fiber content (wt% of DPL fiber on erosion rate of PVA/DPL composite has also been investigated. The neat PVA shows maximum erosion rate at 30° impingement angle whereas PVA/DPL composites exhibit maximum erosion rate at 45° impingement angle irrespective of fiber loading showing semiductile behavior. The erosion efficiency of PVA and its composites varies from 0.735 to 16.289% for different impact velocities studied. The eroded surfaces were observed under scanning electron microscope (SEM to understand the erosion mechanism.

Preparation and Characterization Challenges to Understanding Environmental and Biological Impacts of Ceria Nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Karakoti, Ajay S.; Munusamy, Prabhakaran; Hostetler, Kasey E.; Kodali, Vamsi K.; Kuchibhatla, Satyanarayana V N T; Orr, Galya; Pounds, Joel G.; Teeguarden, Justin G.; Thrall, Brian D.; Baer, Donald R.

2012-08-01

It has been increasingly recognized that understanding and predicting the behaviors of nanoparticles is often limited by the degree to which the particles can be reliably produced and are adequately characterized. Examining data from the literature for ceria nanoparticles suggests that thermal history is one factor that has a strong influence on biological impact. Thermal processing may alter many physicochemical properties of the particles including density, crystal structure and the presence of surface contamination, but these may not be sufficiently recorded or reported to determine the ultimate source of an observed impact. A second example shows the types of difficulties that can be encountered in efforts to apply a well-studied synthesis route to producing well defined particles for biological studies. These examples and others highlight the importance of characterizing particles thoroughly and recording details of particle processing and history that are often not recorded and/or reported.

On the biased motion of a brownian particle for the pausing time behavior of the CTRW

International Nuclear Information System (INIS)

Kim, K.S.

1982-01-01

The purpose of this paper is to discuss the biased Brownian motion with the absorbing barrier for the pausing time behavior of the CTRW (continuous-time random walk method), regarding a Brownian particle as a walker. For two pausing time density functions, the respective values for the transport averaged velocity and the dispersion are calculated as the time t becomes large. (KAERI)

Particle Engineering of Excipients for Direct Compression: Understanding the Role of Material Properties.

Science.gov (United States)

Mangal, Sharad; Meiser, Felix; Morton, David; Larson, Ian

2015-01-01

Tablets represent the preferred and most commonly dispensed pharmaceutical dosage form for administering active pharmaceutical ingredients (APIs). Minimizing the cost of goods and improving manufacturing output efficiency has motivated companies to use direct compression as a preferred method of tablet manufacturing. Excipients dictate the success of direct compression, notably by optimizing powder formulation compactability and flow, thus there has been a surge in creating excipients specifically designed to meet these needs for direct compression. Greater scientific understanding of tablet manufacturing coupled with effective application of the principles of material science and particle engineering has resulted in a number of improved direct compression excipients. Despite this, significant practical disadvantages of direct compression remain relative to granulation, and this is partly due to the limitations of direct compression excipients. For instance, in formulating high-dose APIs, a much higher level of excipient is required relative to wet or dry granulation and so tablets are much bigger. Creating excipients to enable direct compression of high-dose APIs requires the knowledge of the relationship between fundamental material properties and excipient functionalities. In this paper, we review the current understanding of the relationship between fundamental material properties and excipient functionality for direct compression.

Sociocultural Behavior Sensemaking: State of the Art in Understanding the Operational Environment

Science.gov (United States)

2014-01-01

data are then processed and 54 | Visualization for sociocultural understanding assimilated into climate models to better visualize the dynamics of...makers to quickly identify the key policy levers that control system behavior. The C- ROADS model of global climate change (Sterman et al., 2012...data values to generate a trend forecast—the latter is called an Autoregressive Integrated Moving Average ( ARIMA ). The order of the models is

Effect of particle morphology of Ni on the mechanical behavior of AZ91E-Ni coated nano Al2O3 composites

Science.gov (United States)

Sameer Kumar, D.; Suman, K. N. S.; Poddar, Palash

2017-06-01

The properties of any composite always depend on the bonding between the matrix and reinforcement phases. One way of improving the wettability of reinforcement in a matrix is to apply a layer of coating on reinforcing particles. The present study aims at developing Ni coating on nano Al2O3 ceramic particles and dispersing them in AZ91E magnesium matrix material. The electroless plating method has been employed to coat the particles and semi solid stir casting technique was adopted to prepare the composites. Several weight fractions of dispersed phase are considered to analyze the behavior of the fabricated composites. Field emission scanning electron microscopy (FESEM) and x-ray diffraction analysis has been carried out to investigate the distribution of particles and phase characteristics of the proposed material. The physical and mechanical behavior of the material was examined through density measurements, hardness, elastic modulus, ductility and tensile strength calculations. The metal coating on reinforcement aids to promote metal-metal bonding interface reactions which result in improved properties of the composite. Tensile fractography was carried out under FESEM and presented.

#consumingitall: Understanding The Complex Relationship Between Media Consumption And Eating Behaviors

OpenAIRE

Albert, Stephanie L.

2017-01-01

Adolescents spend almost nine hours a day engaging with media. As a result, they are confronted with large amounts of obesogenic content that shapes their understanding of what are normal and acceptable eating behaviors. Utilizing primary data collected from a sample of 4,838 low-income, racially and ethnically diverse middle school students in Los Angeles County, I studied the effects of different types of media use (i.e., social media, TV/movies/videos, gaming, music, Internet) on dietary p...

Influence of nano-AlN particles on thermal conductivity, thermal stability and cure behavior of cycloaliphatic epoxy/trimethacrylate system

Directory of Open Access Journals (Sweden)

2011-02-01

Full Text Available We have prepared a series of nano-sized aluminium nitride (nano-AlN/cycloaliphatic epoxy/trimethacrylate (TMPTMA systems and investigated their morphology, thermal conductivity, thermal stability and curing behavior. Experimental results show that the thermal conductivity of composites increases with the nano-AlN filler content, the maximum value is up to 0.47 W/(m.K. Incorporation of a small amount of the nano-AlN filler into the epoxy/TMPTMA system improves the thermal stability. For instance, the thermal degradation temperature at 5% weight loss of nano-AlN/epoxy/TMPTMA system with only 1 wt% nano-AlN was improved by ~8ºC over the neat epoxy/TMPTMA system. The effect of nano-AlN particles on the cure behavior of epoxy/TMPTMA systems was studied by dynamic differential scanning calorimetry. The results showed that the addition of silane treated nano-AlN particles does not change the curing reaction mechanism and silane treated nano-AlN particles could bring positive effect on the processing of composite since it needs shorter pre-cure time and lower pre-temperature, meanwhile the increase of glass transition temperature of the nanocomposite improves the heat resistance.

Irradiation behavior of the interaction product of U-Mo fuel particle dispersion in an Al matrix

Energy Technology Data Exchange (ETDEWEB)

Kim, Yeon Soo, E-mail: yskim@anl.gov [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Hofman, G.L. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States)

2012-06-15

Highlights: Black-Right-Pointing-Pointer We in-pile tested U-Mo dispersion in Al matrix. Black-Right-Pointing-Pointer We observed interaction layer growth between U-Mo and Al and pore formation there. Black-Right-Pointing-Pointer Pores degrades thermal conductivity and structural integrity of the fueled zone. Black-Right-Pointing-Pointer The amorphous behavior of interaction layers is thought to be the main reason for unstable large pore growth. Black-Right-Pointing-Pointer A mechanism for pore formation and possible remedy to prevent it are proposed. - Abstract: Irradiation performance of U-Mo fuel particles dispersed in Al matrix is stable in terms of fuel swelling and is suitable for the conversion of research and test reactors from highly enriched uranium (HEU) to low enriched uranium (LEU). However, tests of the fuel at high temperatures and high burnups revealed obstacles caused by the interaction layers forming between the fuel particle and matrix. In some cases, fission gas filled pores grow and interconnect in the interdiffusion layer resulting in fuel plate failure. Postirradiation observations are made to examine the behavior of the interdiffusion layers. The interdiffusion layers show a fluid-like behavior characteristic of amorphous materials. In the amorphous interdiffusion layers, fission gas diffusivity is high and the material viscosity is low so that the fission gas pores readily form and grow. Based on the observations, a pore formation mechanism is proposed and potential remedies to suppress the pore growth are also introduced.

Understanding recurrent crime as system-immanent collective behavior.

Science.gov (United States)

Perc, Matjaž; Donnay, Karsten; Helbing, Dirk

2013-01-01

Containing the spreading of crime is a major challenge for society. Yet, since thousands of years, no effective strategy has been found to overcome crime. To the contrary, empirical evidence shows that crime is recurrent, a fact that is not captured well by rational choice theories of crime. According to these, strong enough punishment should prevent crime from happening. To gain a better understanding of the relationship between crime and punishment, we consider that the latter requires prior discovery of illicit behavior and study a spatial version of the inspection game. Simulations reveal the spontaneous emergence of cyclic dominance between "criminals", "inspectors", and "ordinary people" as a consequence of spatial interactions. Such cycles dominate the evolutionary process, in particular when the temptation to commit crime or the cost of inspection are low or moderate. Yet, there are also critical parameter values beyond which cycles cease to exist and the population is dominated either by a stable mixture of criminals and inspectors or one of these two strategies alone. Both continuous and discontinuous phase transitions to different final states are possible, indicating that successful strategies to contain crime can be very much counter-intuitive and complex. Our results demonstrate that spatial interactions are crucial for the evolutionary outcome of the inspection game, and they also reveal why criminal behavior is likely to be recurrent rather than evolving towards an equilibrium with monotonous parameter dependencies.

Understanding recurrent crime as system-immanent collective behavior.

Directory of Open Access Journals (Sweden)

Matjaž Perc

Full Text Available Containing the spreading of crime is a major challenge for society. Yet, since thousands of years, no effective strategy has been found to overcome crime. To the contrary, empirical evidence shows that crime is recurrent, a fact that is not captured well by rational choice theories of crime. According to these, strong enough punishment should prevent crime from happening. To gain a better understanding of the relationship between crime and punishment, we consider that the latter requires prior discovery of illicit behavior and study a spatial version of the inspection game. Simulations reveal the spontaneous emergence of cyclic dominance between "criminals", "inspectors", and "ordinary people" as a consequence of spatial interactions. Such cycles dominate the evolutionary process, in particular when the temptation to commit crime or the cost of inspection are low or moderate. Yet, there are also critical parameter values beyond which cycles cease to exist and the population is dominated either by a stable mixture of criminals and inspectors or one of these two strategies alone. Both continuous and discontinuous phase transitions to different final states are possible, indicating that successful strategies to contain crime can be very much counter-intuitive and complex. Our results demonstrate that spatial interactions are crucial for the evolutionary outcome of the inspection game, and they also reveal why criminal behavior is likely to be recurrent rather than evolving towards an equilibrium with monotonous parameter dependencies.

Simulation of halo particles with Simpsons

International Nuclear Information System (INIS)

Machida, Shinji

2003-01-01

Recent code improvements and some simulation results of halo particles with Simpsons will be presented. We tried to identify resonance behavior of halo particles by looking at tune evolution of individual macro particle

Simulation of halo particles with Simpsons

Science.gov (United States)

Machida, Shinji

2003-12-01

Recent code improvements and some simulation results of halo particles with Simpsons will be presented. We tried to identify resonance behavior of halo particles by looking at tune evolution of individual macro particle.

Pre-asymptotic behavior of single-particle overlap integrals of non-Borromean two-neutron halos

International Nuclear Information System (INIS)

Timofeyuk, N.K.; Tostevin, J.A.; Blokhintsev, L.D.

2003-01-01

For non-Borromean two-neutron halo nuclei, modifications to the behavior of single-particle overlap integrals will arise due to the correlations of the two interacting nucleons in the halo. An additional contribution to the overlap integral can be obtained using the Feynman diagram approach. This additional term is modeled using a simple local potential model. We show that these modifications may play a role in detailed interpretations of experimental results from single-nucleon knockout, transfer, and other reactions that probe the single-nucleon overlap functions

Influence of content and particle size of waste pet bottles on concrete behavior at different w/c ratios

International Nuclear Information System (INIS)

Albano, C.; Camacho, N.; Hernandez, M.; Matheus, A.; Gutierrez, A.

2009-01-01

The goal of this work was to study the mechanical behavior of concrete with recycled Polyethylene Therephtalate (PET), varying the water/cement ratio (0.50 and 0.60), PET content (10 and 20 vol%) and the particle size. Also, the influence of the thermal degradation of PET in the concrete was studied, when the blends were exposed to different temperatures (200, 400, 600 o C). Results indicate that PET-filled concrete, when volume proportion and particle size of PET increased, showed a decrease in compressive strength, splitting tensile strength, modulus of elasticity and ultrasonic pulse velocity; however, the water absorption increased. On the other hand, the flexural strength of concrete-PET when exposed to a heat source was strongly dependent on the temperature, water/cement ratio, as well as on the PET content and particle size. Moreover, the activation energy was affected by the temperature, PET particles location on the slabs and water/cement ratio.

Influence of content and particle size of waste pet bottles on concrete behavior at different w/c ratios.

Science.gov (United States)

Albano, C; Camacho, N; Hernández, M; Matheus, A; Gutiérrez, A

2009-10-01

The goal of this work was to study the mechanical behavior of concrete with recycled Polyethylene Therephtalate (PET), varying the water/cement ratio (0.50 and 0.60), PET content (10 and 20 vol%) and the particle size. Also, the influence of the thermal degradation of PET in the concrete was studied, when the blends were exposed to different temperatures (200, 400, 600 degrees C). Results indicate that PET-filled concrete, when volume proportion and particle size of PET increased, showed a decrease in compressive strength, splitting tensile strength, modulus of elasticity and ultrasonic pulse velocity; however, the water absorption increased. On the other hand, the flexural strength of concrete-PET when exposed to a heat source was strongly dependent on the temperature, water/cement ratio, as well as on the PET content and particle size. Moreover, the activation energy was affected by the temperature, PET particles location on the slabs and water/cement ratio.

Particle pitch angle diffusion due to nonadiabatic effects in the plasma sheet

International Nuclear Information System (INIS)

Gray, P.C.; Lee, L.C.

1982-01-01

In order to understand certain aspects of the plasma sheet dynamics, a numerical study of the nonadiabatic behavior of particles in a model field geometry is performed. The particle's magnetic moment as a function of time is calculated for various initial parameters, corresponding to various particle energies and degrees of field curvature. It is shown that the magnetic moment changes as the particle passes through the plasma sheet and that the magnitude of the change is related to the curvature of the field at the middle of the plasma sheet. The relation of the magnitude of the change in magnetic moment to the particle's pitch and phase angles as it passes through the sheet is numerically resolved. The nature of the change may be considered as a mechanism for pitch angle diffusion, and the diffusion coefficient is calculated. This scattering mechanism is significant for plasma sheet ions (1--10 keV) as well as energetic electrons (>100 keV)

FuturICT: Participatory computing to understand and manage our complex world in a more sustainable and resilient way

OpenAIRE

Helbing, D.; Bishop, S.; Conte, R.; Lukowicz, P.; McCarthy, J. B.

2012-01-01

We have built particle accelerators to understand the forces that make up our physical world. Yet, we do not understand the princi-ples underlying our strongly connected, techno-socio-economic systems. We have enabled ubiquitous Internet connectivity and instant, global information access. Yet we do not understand how it impacts our be-havior and the evolution of society. To fill the knowledge gaps and keep up with the fast pace at which our world is changing, a Knowledge Accelerator must urg...

Bounce behavior of freshly nucleated biogenic secondary organic aerosol particles

Directory of Open Access Journals (Sweden)

A. Virtanen

2011-08-01

Full Text Available The assessment of the climatic impacts and adverse health effects of atmospheric aerosol particles requires detailed information on particle properties. However, very limited information is available on the morphology and phase state of secondary organic aerosol (SOA particles. The physical state of particles greatly affects particulate-phase chemical reactions, and thus the growth rates of newly formed atmospheric aerosol. Thus verifying the physical phase state of SOA particles gives new and important insight into their formation, subsequent growth, and consequently potential atmospheric impacts. According to our recent study, biogenic SOA particles produced in laboratory chambers from the oxidation of real plant emissions as well as in ambient boreal forest atmospheres can exist in a solid phase in size range >30 nm. In this paper, we extend previously published results to diameters in the range of 17–30 nm. The physical phase of the particles is studied by investigating particle bounce properties utilizing electrical low pressure impactor (ELPI. We also investigate the effect of estimates of particle density on the interpretation of our bounce observations. According to the results presented in this paper, particle bounce clearly decreases with decreasing particle size in sub 30 nm size range. The comparison measurements by ammonium sulphate and investigation of the particle impaction velocities strongly suggest that the decreasing bounce is caused by the differences in composition and phase of large (diameters greater than 30 nm and smaller (diameters between 17 and 30 nm particles.

Influence of particle size on the low and high strain rate behavior of dense colloidal dispersions of nanosilica

Energy Technology Data Exchange (ETDEWEB)

Asija, Neelanchali; Chouhan, Hemant; Gebremeskel, Shishay Amare; Bhatnagar, Naresh, E-mail: nareshb@mech.iitd.ac.in [Indian Institute of Technology Delhi, Mechanical Engineering Department (India)

2017-01-15

Shear thickening is a non-Newtonian flow behavior characterized by the increase in apparent viscosity with the increase in applied shear rate, particularly when the shear rate exceeds a critical value termed as the critical shear rate (CSR). Due to this remarkable property of shear-thickening fluids (STFs), they are extensively used in hip protection pads, protective gear for athletes, and more recently in body armor. The use of STFs in body armor has led to the development of the concept of liquid body armor. In this study, the effect of particle size is explored on the low and high strain rate behavior of nanosilica dispersions, so as to predict the efficacy of STF-aided personal protection systems (PPS), specifically for ballistic applications. The low strain rate study was conducted on cone and plate rheometer, whereas the high strain rate characterization of STF was conducted on in-house fabricated split Hopkinson pressure bar (SHPB) system. Spherical nanosilica particles of three different sizes (100, 300, and 500 nm) as well as fumed silica particles of four different specific surface areas (Aerosil A-90, A-130, A-150, and A-200), respectively, were used in this study. The test samples were prepared by dispersing nanosilica particles in polypropylene glycol (PPG) using ultrasonic homogenization method. The low strain rate studies aided in determining the CSR of the synthesized STF dispersions, whereas the high strain rate studies explored the impact-resisting ability of STFs in terms of the impact toughness and the peak stress attained during the impact loading of STF in SHPB testing.

Lagrangian Trajectory Modeling of Lunar Dust Particles

Science.gov (United States)

Lane, John E.; Metzger, Philip T.; Immer, Christopher D.

2008-01-01

Apollo landing videos shot from inside the right LEM window, provide a quantitative measure of the characteristics and dynamics of the ejecta spray of lunar regolith particles beneath the Lander during the final 10 [m] or so of descent. Photogrammetry analysis gives an estimate of the thickness of the dust layer and angle of trajectory. In addition, Apollo landing video analysis divulges valuable information on the regolith ejecta interactions with lunar surface topography. For example, dense dust streaks are seen to originate at the outer rims of craters within a critical radius of the Lander during descent. The primary intent of this work was to develop a mathematical model and software implementation for the trajectory simulation of lunar dust particles acted on by gas jets originating from the nozzle of a lunar Lander, where the particle sizes typically range from 10 micron to 500 micron. The high temperature, supersonic jet of gas that is exhausted from a rocket engine can propel dust, soil, gravel, as well as small rocks to high velocities. The lunar vacuum allows ejected particles to travel great distances unimpeded, and in the case of smaller particles, escape velocities may be reached. The particle size distributions and kinetic energies of ejected particles can lead to damage to the landing spacecraft or to other hardware that has previously been deployed in the vicinity. Thus the primary motivation behind this work is to seek a better understanding for the purpose of modeling and predicting the behavior of regolith dust particle trajectories during powered rocket descent and ascent.

A study of particle size distribution in zirconia-alumina powders

International Nuclear Information System (INIS)

Ramakrishnan, K.N.; Venkadesan, S.; Nagarajan, R.

1996-01-01

Powder particles, in general are characterized in terms of particle size, size distributions and composition for reasons associated with manufacturing problem based upon product quality, manufacturing convenience, cost and product handling convenience. Particle size analysis or the measurement of particle size distribution is a common effort in any physical, chemical or mechanical processes. This information and processing methods are intricate factors that relate to material behavior and/or physical properties of the fabricated product. The requirements for the formation of a product of particulate solids and its strength varies as the particle size and the size distribution changes. Also the transport properties and the chemical activity are related to the particle size and the size distribution. The choice of a distribution to represent a physical system is generally motivated by an understanding of the nature of underlying phenomenon and is verified by the available data. After a model has been chosen, its parameter must be determined. The reasonableness of a selected model on the basis of given data is especially important when the model is to be used for prediction. Two different approaches in this problem are probability plotting and statistical tests

The Perspectives to Understand Social Marketing as an Approach in Influencing Consumer Behavior for Good

Directory of Open Access Journals (Sweden)

Iin Mayasari

2012-05-01

Full Text Available This study is a conceptual paper and highlights perspectives to understand social marketing as an approach to bring about voluntary and socially desirable consumer behavior. The perspective is considered as an alternative way to comprehend consumer behavior change for good as a multi-factor driven action. Hence, social marketing is also considered as a discipline that can be analyzed from multiple perspectives including a behavioral change perspective and a relationship perspective. Each perspective is elaborated by doing a review of existing literature and research. This study shows that social marketing is not only the application of marketing programs to shape consumer behavior, but also a process involving individual, society, and government to make a better life of society.

A Visual Analytics Approach for Detecting and Understanding Anomalous Resident Behaviors in Smart Healthcare

Directory of Open Access Journals (Sweden)

Zhifang Liao

2017-03-01

Full Text Available With the development of science and technology, it is possible to analyze residents’ daily behaviors for the purpose of smart healthcare in the smart home environment. Many researchers have begun to detect residents’ anomalous behaviors and assess their physical condition, but these approaches used by the researchers are often caught in plight caused by a lack of ground truth, one-sided analysis of behavior, and difficulty of understanding behaviors. In this paper, we put forward a smart home visual analysis system (SHVis to help analysts detect and comprehend unusual behaviors of residents, and predict the health information intelligently. Firstly, the system classifies daily activities recorded by sensor devices in smart home environment into different categories, and discovers unusual behavior patterns of residents living in this environment by using various characteristics extracted from those activities and appropriate unsupervised anomaly detection algorithm. Secondly, on the basis of figuring out the residents’ anomaly degree of every date, we explore the daily behavior patterns and details with the help of several visualization views, and compare and analyze residents’ activities of various dates to find the reasons why residents act unusually. In the case study of this paper, we analyze residents’ behaviors that happened over two months and find unusual indoor behaviors and give health advice to the residents.

Found in translation: understanding the biology and behavior of experimental traumatic brain injury

Science.gov (United States)

Bondi, Corina O.; Semple, Bridgette D.; Noble-Haeusslein, Linda J.; Osier, Nicole D.; Carlson, Shaun W.; Dixon, C. Edward; Giza, Christopher C.; Kline, Anthony E.

2014-01-01

BONDI, C.O., B.D. Semple, L.J. Noble-Haeusslein, N.D. Osier, S.W. Carlson, C.E. Dixon, C.C. Giza and A.E. Kline. Found in translation: understanding the biology and behavior of experimental traumatic brain injury. NEUROSCI BIOBEHAV REV. The aim of this review is to discuss in greater detail the topics covered in the recent symposium entitled “Traumatic brain injury: laboratory and clinical perspectives,” presented at the 2014 International Behavioral Neuroscience Society annual meeting. Herein we review contemporary laboratory models of traumatic brain injury (TBI) including common assays for sensorimotor and cognitive behavior. New modalities to evaluate social behavior after injury to the developing brain, as well as the attentional set-shifting test (AST) as a measure of executive function in TBI, will be highlighted. Environmental enrichment (EE) will be discussed as a preclinical model of neurorehabilitation, and finally, an evidence-based approach to sports-related concussion will be considered. The review consists predominantly of published data, but some discussion of ongoing or future directions is provided. PMID:25496906

Particle cosmology

CERN Multimedia

CERN. Geneva

2007-01-01

The understanding of the Universe at the largest and smallest scales traditionally has been the subject of cosmology and particle physics, respectively. Studying the evolution of the Universe connects today's large scales with the tiny scales in the very early Universe and provides the link between the physics of particles and of the cosmos. This series of five lectures aims at a modern and critical presentation of the basic ideas, methods, models and observations in today's particle cosmology.

Studies of Fundamental Particle Dynamics in Microgravity

Science.gov (United States)

Rangel, Roger; Trolinger, James D.; Coimbra, Carlos F. M.; Witherow, William; Rogers, Jan; Rose, M. Franklin (Technical Monitor)

2001-01-01

This work summarizes theoretical and experimental concepts used to design the flight experiment mission for SHIVA - Spaceflight Holography Investigation in a Virtual Apparatus. SHIVA is a NASA project that exploits a unique, holography-based, diagnostics tool to understand the behavior of small particles subjected to transient accelerations. The flight experiments are designed for testing model equations, measuring g, g-jitter, and other microgravity phenomena. Data collection will also include experiments lying outside of the realm of existing theory. The regime under scrutiny is the low Reynolds number, Stokes regime or creeping flow, which covers particles and bubbles moving at very low velocity. The equations describing this important regime have been under development and investigation for over 100 years and yet a complete analytical solution of the general equation had remained elusive yielding only approximations and numerical solutions. In the course of the ongoing NASA NRA, the first analytical solution of the general equation was produced by members of the investigator team using the mathematics of fractional derivatives. This opened the way to an even more insightful and important investigation of the phenomena in microgravity. Recent results include interacting particles, particle-wall interactions, bubbles, and Reynolds numbers larger than unity. The Space Station provides an ideal environment for SHIVA. Limited ground experiments have already confirmed some aspects of the theory. In general the space environment is required for the overall experiment, especially for cases containing very heavy particles, very light particles, bubbles, collections of particles and for characterization of the space environment and its effect on particle experiments. Lightweight particles and bubbles typically rise too fast in a gravitational field and heavy particles sink too fast. In a microgravity environment, heavy and light particles can be studied side-by-side for

Addressing of LnCaP Cell Using Magnetic Particles Assisted Impedimetric Microelectrode.

Science.gov (United States)

Nguyen, Dung Thi Xuan; Tran, Trong Binh; Nguyen, Phuong-Diem; Min, Junhong

2016-03-01

In this study, we provide a facile, effective technique for a simple isolation and enrichment of low metastatic prostate tumor cell LNCaP using biocompatible, magnetic particles asissted impedimetric sensing system. Hydrophobic cell membrane anchors (BAM) were generated onto magnetic particles which diameters vary from 50 nm to 5 μm and were used to capture LNCaP cells from the suspension. Finally, magnetic particle-LNCaP complex were addressed onto the surface of the interdigitated microelectrode (IDM). Cell viability was monitored by our laboratory developed-technique Electrical Cell Substrate Impedance Sensing (ECIS). The results reavealed that 50 nm-magnetic particles showed best performance in terms of cell separation and cell viability. This technique provides a simple and efficient method for the direct addressing of LNCaP cell on the surface and enhances better understanding of cell behavior for cancer management in the near future.

Voices of the Filipino Community Describing the Importance of Family in Understanding Adolescent Behavioral Health Needs.

Science.gov (United States)

Javier, Joyce R; Galura, Kristina; Aliganga, Frank Anthony P; Supan, Jocelyn; Palinkas, Lawrence A

Filipinos are a large, yet invisible, minority at high risk for adolescent behavioral health problems. Limited research describes the family as offering a source of positive support for some Filipino youths and yet for some it is also a source of stress and isolation, leading to struggles with adolescent depression and suicidal behavior. This article describes a qualitative study that investigates the role of family when understanding behavioral health needs among Filipino adolescents. Findings highlight the importance of addressing family cohesion when designing interventions aimed at improving the well-being of Filipino youth.

Gas-particle phase partitioning and particle size distribution of chlorinated and brominated polycyclic aromatic hydrocarbons in haze.

Science.gov (United States)

Jin, Rong; Zheng, Minghui; Yang, Hongbo; Yang, Lili; Wu, Xiaolin; Xu, Yang; Liu, Guorui

2017-12-01

Chlorinated and brominated polycyclic aromatic hydrocarbons (Cl/Br-PAHs) are emerging semi-volatile organic pollutants in haze-associated particulate matter (PM). Their gas-particle phase partitioning and distribution among PM fractions have not been clarified. Clarification would increase understanding of atmospheric behavior and health risks of Cl/Br-PAHs. In this study, samples of the gas phase and 4 PM phases (aerodynamic diameters (d ae ) > 10 μm, 2.5-10 μm, 1.0-2.5 μm, and <1.0 μm) were collected simultaneously during haze events in Beijing and analyzed. Normalized histogram distribution indicated that the Cl/Br-PAHs tended to adhere to fine particles. Over 80% of the Cl-PAHs and 70% of the Br-PAHs were associated with fine PM (d ae  < 2.5 μm). The gas-particle phase partitioning and PM distribution of Cl/Br-PAHs when heating of buildings was required, which was associated with haze events, were obviously different from those when heating was not required. The relationship between the logarithmic geometric mean diameters of the Cl/Br-PAH congeners and reciprocal of the temperature (1/T) suggested that low air temperatures during the heating period could lead to high proportions of Cl/Br-PAHs in the fine particles. Increased coal burning during the heating period also contributed to high Cl/Br-PAH loads in the fine particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Non-equilibrium effects in the magnetic behavior of Co_3O_4 nanoparticles

OpenAIRE

Bisht, Vijay; Rajeev, K. P.

2011-01-01

We report detailed studies on non-equilibrium magnetic behavior of antiferromagnetic Co_3O_4 nanoparticles. Temperature and field dependence of magnetization, wait time dependence of magnetic relaxation (aging), memory effects and temperature dependence of specific heat have been investigated to understand the magnetic behavior of these particles. We find that the system shows some features characteristic of nanoparticle magnetism such as bifurcation of field cooled (FC) and zero field cooled...

Long range correlations, leading particle spectrum and correlations with leading particles

International Nuclear Information System (INIS)

Ilgenfritz, E.M.

1976-05-01

The unitary cluster emission model by de Groot and Ruijgrok is discussed as an approach to understand the leading particle behaviour. Consequences of the model concerning co--rrelations between leading particles and produced particles in the central region are considered. No satisfactory agreement was found. Production of leading clusters is argued for being an essential feature of these correlations. (author)

Effect of Particle Size Distribution on Slurry Rheology: Nuclear Waste Simulant Slurries

International Nuclear Information System (INIS)

Chun, Jaehun; Oh, Takkeun; Luna, Maria L.; Schweiger, Michael J.

2011-01-01

Controlling the rheological properties of slurries has been of great interest in various industries such as cosmetics, ceramic processing, and nuclear waste treatment. Many physicochemical parameters, such as particle size, pH, ionic strength, and mass/volume fraction of particles, can influence the rheological properties of slurry. Among such parameters, the particle size distribution of slurry would be especially important for nuclear waste treatment because most nuclear waste slurries show a broad particle size distribution. We studied the rheological properties of several different low activity waste nuclear simulant slurries having different particle size distributions under high salt and high pH conditions. Using rheological and particle size analysis, it was found that the percentage of colloid-sized particles in slurry appears to be a key factor for rheological characteristics and the efficiency of rheological modifiers. This behavior was shown to be coupled with an existing electrostatic interaction between particles under a low salt concentration. Our study suggests that one may need to implement the particle size distribution as a critical factor to understand and control rheological properties in nuclear waste treatment plants, such as the U.S. Department of Energy's Hanford and Savannah River sites, because the particle size distributions significantly vary over different types of nuclear waste slurries.

Particle adhesion and removal

CERN Document Server

Mittal, K L

2015-01-01

The book provides a comprehensive and easily accessible reference source covering all important aspects of particle adhesion and removal.  The core objective is to cover both fundamental and applied aspects of particle adhesion and removal with emphasis on recent developments.  Among the topics to be covered include: 1. Fundamentals of surface forces in particle adhesion and removal.2. Mechanisms of particle adhesion and removal.3. Experimental methods (e.g. AFM, SFA,SFM,IFM, etc.) to understand  particle-particle and particle-substrate interactions.4. Mechanics of adhesion of micro- and  n

Influence of Boron on the Creep Behavior and the Microstructure of Particle Reinforced Aluminum Matrix Composites

Directory of Open Access Journals (Sweden)

Steve Siebeck

2018-02-01

Full Text Available The reinforcement of aluminum alloys with particles leads to the enhancement of their mechanical properties at room temperature. However, the creep behavior at elevated temperatures is often negatively influenced. This raises the question of how it is possible to influence the creep behavior of this type of material. Within this paper, selected creep and tensile tests demonstrate the beneficial effects of boron on the properties of precipitation-hardenable aluminum matrix composites (AMCs. The focus is on the underlying microstructure behind this effect. For this purpose, boron was added to AMCs by means of mechanical alloying. Comparatively higher boron contents than in steel are investigated in order to be able to record their influence on the microstructure including the formation of potential new phases as well as possible. While the newly formed phase Al3BC can be reliably detected by X-ray diffraction (XRD, it is difficult to obtain information about the phase distribution by means of scanning electron microscopy (SEM and scanning transmission electron microscopy (STEM investigations. An important contribution to this is finally provided by the investigation using Raman microscopy. Thus, the homogeneous distribution of finely scaled Al3BC particles is detectable, which allows conclusions about the microstructure/property relationship.

Morphology and orientational behavior of silica-coated spindle-type hematite particles in a magnetic field probed by small-angle X-ray scattering.

Science.gov (United States)

Reufer, Mathias; Dietsch, Hervé; Gasser, Urs; Hirt, Ann; Menzel, Andreas; Schurtenberger, Peter

2010-04-15

Form factor and magnetic properties of silica-coated spindle-type hematite nanoparticles are determined from SAXS measurements with applied magnetic field and magnetometry measurements. The particle size, polydispersity and porosity are determined using a core-shell model for the form factor. The particles are found to align with their long axis perpendicular to the applied field. The orientational order is determined from the SAXS data and compared to the orientational order obtained from magnetometry. The direct access to both, the orientational order of the particles, and the magnetic moments allow one to determine the magnetic properties of the individual spindle-type hematite particles. We study the influence of the silica coating on the magnetic properties and find a fundamentally different behavior of silica-coated particles. The silica coating reduces the effective magnetic moment of the particles. This effect is enhanced with field strength and can be explained by superparamagnetic relaxation in the highly porous particles.

Localized corrosion in AA2099-T83 aluminum–lithium alloy: The role of intermetallic particles

Energy Technology Data Exchange (ETDEWEB)

Ma, Y., E-mail: myl@cqut.edu.cn [College of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054 (China); Zhou, X., E-mail: xiaorong.zhou@manchester.ac.uk [Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester, M13 9PL (United Kingdom); Huang, W. [College of Materials Science and Engineering, Chongqing University of Technology, Chongqing, 400054 (China); Thompson, G.E. [Corrosion and Protection Centre, School of Materials, The University of Manchester, Manchester, M13 9PL (United Kingdom); Zhang, X.; Luo, C.; Sun, Z. [Beijing Institute of Aeronautical Materials, Beijing, 100095 (China)

2015-07-01

The corrosion behavior of intermetallic particles and their role in the process of localized corrosion in AA2099-T83 aluminum–lithium alloy has been investigated. It was found that both high- and low-copper containing Al–Fe–Mn–Cu-(Li) particles could result in superficial pits on the alloy, and the high level of lithium in the high-copper-containing particles rendered them electrochemically more active than the low-copper-containing particles. Additionally, severe localized corrosion was found not to be directly related to the distribution of constituent particles in the alloy. The findings are not only relevant to the understanding of corrosion mechanism but also beneficial to the evaluation of thermomechanical treatments of the alloy. - Highlights: • Lithium was detected in the high-copper-containing Al–Fe–Mn–Cu particles. • The high-copper-containing particles were relatively more active. • Localized corrosion induced by constituent particles was superficial. • Severe localized corrosion in the alloy propagated via grain/subgrain boundaries. • Severe localized corrosion was not related to constituent particles.

Lie-Telling Behavior in Children with Autism and Its Relation to False-Belief Understanding

Science.gov (United States)

Talwar, Victoria; Zwaigenbaum, Lonnie; Goulden, Keith J.; Manji, Shazeen; Loomes, Carly; Rasmussen, Carmen

2012-01-01

Children's lie-telling behavior and its relation to false-belief understanding was examined in children with autism spectrum disorders (ASD; n = 26) and a comparison group of typically developing children (n = 27). Participants were assessed using a temptation resistance paradigm, in which children were told not to peek at a forbidden toy while…

Long-range forces affecting equilibrium inertial focusing behavior in straight high aspect ratio microfluidic channels

Energy Technology Data Exchange (ETDEWEB)

Reece, Amy E.; Oakey, John, E-mail: joakey@uwyo.edu [Department of Chemical Engineering, University of Wyoming, Laramie, Wyoming 82071 (United States)

2016-04-15

The controlled and directed focusing of particles within flowing fluids is a problem of fundamental and technological significance. Microfluidic inertial focusing provides passive and precise lateral and longitudinal alignment of small particles without the need for external actuation or sheath fluid. The benefits of inertial focusing have quickly enabled the development of miniaturized flow cytometers, size-selective sorting devices, and other high-throughput particle screening tools. Straight channel inertial focusing device design requires knowledge of fluid properties and particle-channel size ratio. Equilibrium behavior of inertially focused particles has been extensively characterized and the constitutive phenomena described by scaling relationships for straight channels of square and rectangular cross section. In concentrated particle suspensions, however, long-range hydrodynamic repulsions give rise to complex particle ordering that, while interesting and potentially useful, can also dramatically diminish the technique’s effectiveness for high-throughput particle handling applications. We have empirically investigated particle focusing behavior within channels of increasing aspect ratio and have identified three scaling regimes that produce varying degrees of geometrical ordering between focused particles. To explore the limits of inertial particle focusing and identify the origins of these long-range interparticle forces, we have explored equilibrium focusing behavior as a function of channel geometry and particle concentration. Experimental results for highly concentrated particle solutions identify equilibrium thresholds for focusing that scale weakly with concentration and strongly with channel geometry. Balancing geometry mediated inertial forces with estimates for interparticle repulsive forces now provide a complete picture of pattern formation among concentrated inertially focused particles and enhance our understanding of the fundamental limits

Research on the fundamental process of thermal-hydraulic behaviors in severe accident. Vapor film collapse behavior on high temperature particle surface. JAERI's nuclear research promotion program, H10-027-3. Contract research

International Nuclear Information System (INIS)

Abe, Yutaka

2002-03-01

The experimental researches were conducted to study vapor film collapse behavior on high temperature melted core material coarsely mixed in the coolant under the film boiling condition. The film collapse is very important incipient incident of the trigger process for the vapor explosion in sever accident of nuclear reactor. In the experiment, pressure pulse was applied to the vapor film on a high temperature particle surface simulating melted core material to observed microscopic vapor film collapse behavior with a high-speed video camera of 40,500 fps. The particle surface temperature and pressure around the particle were simultaneously measured. The transition of the vapor film thickness and two-dimensional vapor-liquid interface movement and the velocity were estimated with visual data analysis technique, PIV and digital data analysis technique. Furthermore, heat conduction analysis was performed to estimate the vapor-liquid interfacial temperature with the measured temperature and estimated vapor film thickness. As the results, it was clarified that the vapor-liquid interface changed white from transparent view for all the experimental conditions. It is also clarified that the vapor-liquid interfacial temperature decreased under the saturation temperature when the pressure pulse arrive at the particle. The experimental facts indicates the possibility that the vapor film collapse occurs due to the liquid phase homogeneous moving toward the particle drove by the pressure reduction caused by the phase change inside the vapor film. (author)

The Asymptotic Behavior of Particle Size Distribution Undergoing Brownian Coagulation Based on the Spline-Based Method and TEMOM Model

Directory of Open Access Journals (Sweden)

Qing He

2018-01-01

Full Text Available In this paper, the particle size distribution is reconstructed using finite moments based on a converted spline-based method, in which the number of linear system of equations to be solved reduced from 4m × 4m to (m + 3 × (m + 3 for (m + 1 nodes by using cubic spline compared to the original method. The results are verified by comparing with the reference firstly. Then coupling with the Taylor-series expansion moment method, the evolution of particle size distribution undergoing Brownian coagulation and its asymptotic behavior are investigated.

A learning-style theory for understanding autistic behaviors

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Ning eQian

2011-08-01

Full Text Available Understanding autism’s ever-expanding array of behaviors, from sensation to cognition, is a major challenge. We posit that autistic and typically-developing brains implement different algorithms that are better suited to learn, represent, and process different tasks; consequently, they develop different interests and behaviors. Computationally, a continuum of algorithms exists, from lookup-table (LUT learning, which aims to store experiences precisely, to interpolation (INT learning, which focuses on extracting underlying statistical structure (regularities from experiences. We hypothesize that autistic and typical brains, respectively, are biased toward LUT and INT learning, in low and high dimensional feature spaces, possibly because of their narrow and broad tuning functions. The LUT style is good at learning relationships that are local, precise, rigid, and contain little regularity for generalization (e.g., the name-number association in a phonebook. However, it is poor at learning relationships that are context dependent, noisy, flexible, and do contain regularities for generalization (e.g., associations between gaze direction and intention, language and meaning, sensory input and interpretation, motor-control signal and movement, and social situation and proper response. The LUT style poorly compresses information, resulting in inefficiency, sensory overload (overwhelm, restricted interests, and resistance to change. It also leads to poor prediction and anticipation, frequent surprises and over-reaction (hyper-sensitivity, impaired attentional selection and switching, concreteness, strong local focus, weak adaptation, and superior and inferior performances on simple and complex tasks. The spectrum nature of autism can be explained by different degrees of LUT learning among different individuals, and in different systems of the same individual. Our theory suggests that therapy should focus on training autistic LUT algorithm to learn

A Learning-Style Theory for Understanding Autistic Behaviors

Science.gov (United States)

Qian, Ning; Lipkin, Richard M.

2011-01-01

Understanding autism's ever-expanding array of behaviors, from sensation to cognition, is a major challenge. We posit that autistic and typically developing brains implement different algorithms that are better suited to learn, represent, and process different tasks; consequently, they develop different interests and behaviors. Computationally, a continuum of algorithms exists, from lookup table (LUT) learning, which aims to store experiences precisely, to interpolation (INT) learning, which focuses on extracting underlying statistical structure (regularities) from experiences. We hypothesize that autistic and typical brains, respectively, are biased toward LUT and INT learning, in low- and high-dimensional feature spaces, possibly because of their narrow and broad tuning functions. The LUT style is good at learning relationships that are local, precise, rigid, and contain little regularity for generalization (e.g., the name–number association in a phonebook). However, it is poor at learning relationships that are context dependent, noisy, flexible, and do contain regularities for generalization (e.g., associations between gaze direction and intention, language and meaning, sensory input and interpretation, motor-control signal and movement, and social situation and proper response). The LUT style poorly compresses information, resulting in inefficiency, sensory overload (overwhelm), restricted interests, and resistance to change. It also leads to poor prediction and anticipation, frequent surprises and over-reaction (hyper-sensitivity), impaired attentional selection and switching, concreteness, strong local focus, weak adaptation, and superior and inferior performances on simple and complex tasks. The spectrum nature of autism can be explained by different degrees of LUT learning among different individuals, and in different systems of the same individual. Our theory suggests that therapy should focus on training autistic LUT algorithm to learn regularities

Toward a qualitative understanding of binge-watching behaviors: A focus group approach.

Science.gov (United States)

Flayelle, Maèva; Maurage, Pierre; Billieux, Joël

2017-12-01

Background and aims Binge-watching (i.e., seeing multiple episodes of the same TV series in a row) now constitutes a widespread phenomenon. However, little is known about the psychological factors underlying this behavior, as reflected by the paucity of available studies, most merely focusing on its potential harmfulness by applying the classic criteria used for other addictive disorders without exploring the uniqueness of binge-watching. This study thus aimed to take the opposite approach as a first step toward a genuine understanding of binge-watching behaviors through a qualitative analysis of the phenomenological characteristics of TV series watching. Methods A focus group of regular TV series viewers (N = 7) was established to explore a wide range of aspects related to TV series watching (e.g., motives, viewing practices, and related behaviors). Results A content analysis identified binge-watching features across three dimensions: TV series watching motivations, TV series watching engagement, and structural characteristics of TV shows. Most participants acknowledged that TV series watching can become addictive, but they all agreed having trouble recognizing themselves as truly being an "addict." Although obvious connections could be established with substance addiction criteria and symptoms, such parallelism appeared to be insufficient, as several distinctive facets emerged (e.g., positive view, transient overinvolvement, context dependency, and low everyday life impact). Discussion and conclusion The research should go beyond the classic biomedical and psychological models of addictive behaviors to account for binge-watching in order to explore its specificities and generate the first steps toward an adequate theoretical rationale for these emerging problematic behaviors.

Free-charged-particle behavior in intense laser fields. Technical progress report, July 15, 1980-July 14, 1981

International Nuclear Information System (INIS)

Fradkin, D.M.

1982-01-01

The effects of intense laser fields on electrons, and what features might arise in the electrons' behavior as a result of the interaction are studied. Earlier work involving a classical treatment through second order of the Lorentz-Dirac equation indicated that with just a laser field, and no auxiliary fields, radiation reaction effects allowed an asymptotic transfer of energy-momentum from an intense laser pulse to a charged particle itself. This work was extended to third order, and explicit expressions for the particle's maximum energy gain per pulse show that it depends primarily on the total pulse energy per unit area of pulse front, and that the influence of laser polarization and frequency (which only come into play in a third-order treatment) are not very significant

Transient Liquid Phase Behavior of Sn-Coated Cu Particles and Chip Bonding using Paste Containing the Particles

Directory of Open Access Journals (Sweden)

Hwang Jun Ho

2017-06-01

Full Text Available Sn-coated Cu particles were prepared as a filler material for transient liquid phase (TLP bonding. The thickness of Sn coating was controlled by controlling the number of plating cycles. The Sn-coated Cu particles best suited for TLP bonding were fabricated by Sn plating thrice, and the particles showed a pronounced endothermic peak at 232°C. The heating of the particles for just 10 s at 250°C destroyed the initial core-shell structure and encouraged the formation of Cu-Sn intermetallic compounds. Further, die bonding was also successfully performed at 250°C under a slight bonding pressure of around 0.1 MPa using a paste containing the particles. The bonding time of 30 s facilitated the bonding of Sn-coated Cu particles to the Au surface and also increased the probability of network formation between particles.

Attitudes and defaults save lives and protect the environment jointly and compensatorily: understanding the behavioral efficacy of nudges and other structural interventions.

Science.gov (United States)

Kaiser, Florian G; Arnold, Oliver; Otto, Siegmar

2014-09-01

A better understanding of when and why nudges (e.g., defaults, visibility or accessibility alterations) and other structural behavior-change measures work or fail can help avoid subsequent surprises such as unexpected political opposition. In this paper, we challenge the unilateral focus on structural interventions-which seemingly control people's behavioral decisions-as such a focus ignores the flipside-namely, attitudes or, as they are called in economics, preferences. We argue for a conceptual understanding of individual behavior that views personal attitudes and behavioral costs as its two separate compensatorily effective determinants. This classical understanding was reintroduced into attitude research as the Campbell paradigm. In the logic of the Campbell paradigm, a person's attitude becomes obvious in the face of the behavioral costs the person surmounts. Technically, individual attitudes reveal themselves in a set of cost-dependent transitively ordered performances. Behavioral costs in turn reflect the structural boundary conditions that are relevant as obstructive and/or supportive environmental forces that generically affect a specific behavior. So far, our research on people's attitudes toward environmental protection has demonstrated that the Campbell paradigm-and thus its conceptual account of individual behavior-holds true for approximately 95% of the people in a given society.

Understanding of flux-limited behaviors of heat transport in nonlinear regime

Energy Technology Data Exchange (ETDEWEB)

Guo, Yangyu, E-mail: yangyuhguo@gmail.com [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics and CNMM, Tsinghua University, Beijing 100084 (China); Jou, David, E-mail: david.jou@uab.es [Departament de Física, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia (Spain); Wang, Moran, E-mail: mrwang@tsinghua.edu [Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Engineering Mechanics and CNMM, Tsinghua University, Beijing 100084 (China)

2016-01-28

The classical Fourier's law of heat transport breaks down in highly nonequilibrium situations as in nanoscale heat transport, where nonlinear effects become important. The present work is aimed at exploring the flux-limited behaviors based on a categorization of existing nonlinear heat transport models in terms of their theoretical foundations. Different saturation heat fluxes are obtained, whereas the same qualitative variation trend of heat flux versus exerted temperature gradient is got in diverse nonlinear models. The phonon hydrodynamic model is proposed to act as a standard to evaluate other heat flux limiters because of its more rigorous physical foundation. A deeper knowledge is thus achieved about the phenomenological generalized heat transport models. The present work provides deeper understanding and accurate modeling of nonlocal and nonlinear heat transport beyond the diffusive limit. - Highlights: • Exploring flux-limited behaviors based on a categorization of existing nonlinear heat transport models. • Proposing phonon hydrodynamic model as a standard to evaluate heat flux limiters. • Providing accurate modeling of nonlocal and nonlinear heat transport beyond the diffusive limit.

Effects of exposure to 56Fe particles of protons on fixed-ratio operant responding in rats

International Nuclear Information System (INIS)

Rabin, B.M.; Buhler, L.L.; Jenkins, D.G.; Joseph, J.A.; Shukitt-Hale, B.

2002-01-01

On long-duration trips outside of the magnetosphere, astronauts will be exposed to protons and to heavy particles which can affect their performance of required tasks. It is essential to determine the range of behaviors that might be affected by exposure to these types of radiation in order to understand the nature of behavioral deficits and to develop effective countermeasures. The present experiment examined the ability of rats to make an operant response following exposure to protons (250 MeV, 4 Gy) or 56 Fe particles (1 GeV/n, 1 or 2 Gy). Following irradiation, rats were trained to press a lever in order to obtain food reinforcement. They were then placed on an ascending fixed-ratio schedule from FR-1 (each lever press rewarded with a food pellet) through FR-35 (35 lever presses required for 1 food pellet). Rats exposed to 4 Gy of protons or 1 Gy of 56 Fe particles responded similarly to controls, increasing their rate of responding as the ratio increased. However, rats exposed to 2 Gy of 56 Fe particles failed to increase their rate of responding at ratios greater than FR-20, indicating that rats exposed to 2 Gy of 56 Fe particles cannot respond appropriately to increasing work requirements. (author)

Fundamental Issues of Nano-fluid Behavior

International Nuclear Information System (INIS)

Williams, Wesley C.

2006-01-01

This paper will elucidate some of the behaviors of nano-fluids other than the abnormal conductivity enhancement, which are of importance to the experimental and engineering use of nano-fluids. Nano-fluid is the common name of any sol colloid involving nano-scale (less than 100 nm) sized particles dispersed within a base fluid. It has been shown previously that the dispersion of nano-particulate metallic oxides into water can increase thermal conductivity up to 30-40% over that of the base fluid and anomalously more than the mere weighed average of the colloid. There is a great potential for the use of nano-fluids as a way to enhance fluid/thermal energy transfer systems. Due to the recentness of nano-fluid science, there are still many issues which have not been fully investigated. This paper should act as a primer for the basic understanding of nano-fluid behavior. Particle size and colloid stability are of key importance to the functionality of nano-fluids. The pH and concentration/loading of nano-fluids can alter the size of the nano-particles and also the stability of the fluids. It will be shown through experiment and colloid theory the importance of these parameters. Furthermore, most of the existing literature uses volume percentage as the measure of particle loading, which can often be misleading. There will be discussion of this and other misleading ideas in nano-fluid science. (author)

Aging behavior and mechanical properties of maraging steels in the presence of submicrocrystalline Laves phase particles

International Nuclear Information System (INIS)

Mahmoudi, A.; Ghavidel, M.R. Zamanzad; Nedjad, S. Hossein; Heidarzadeh, A.; Ahmadabadi, M. Nili

2011-01-01

Cold rolling and annealing of homogenized Fe-Ni-Mn-Mo-Ti-Cr maraging steels resulted in the formation of submicrocrystalline Fe 2 (Mo,Ti) Laves phase particles. Optical and scanning electron microscopy, X-ray diffraction, tensile and hardness tests were used to study the microstructure, aging behavior and mechanical properties of the annealed steels. The annealed microstructures showed age hardenability during subsequent isothermal aging at 753 K. Ultrahigh fracture stress but poor tensile ductility was obtained after substantial age hardening in the specimens with 2% and 4% chromium. Increasing chromium addition up to 6% toughened the aged microstructure at the expense of the fracture stress by increasing the volume fraction of retained austenite. The Laves phase particles acted as crack nucleation sites during tensile deformation. - Highlights: → Laves phases dispersed in a BCC iron matrix by annealing of cold rolled samples. → The samples showed age hardenability during subsequent isothermal aging at 753 K. → Ultrahigh fracture stress but poor ductility was obtained after age hardening. → Increasing chromium addition toughened the aged microstructure. → Laves phase particles acting as crack nucleation sites during tensile deformation.

Theory of mind understanding and empathic behavior in children with autism spectrum disorders.

Science.gov (United States)

Peterson, Candida

2014-12-01

This paper begins with a review of past research on theory of mind and empathy in children with ASD. Using varied operational definitions of empathy ranging from physiological heart rate through story vignettes to reports by privileged observers (e.g., teachers) of children's empathic behavior, results of previous studies are limited and contradictory. Thus new evidence is needed to answer two key questions: Are children with ASD less empathic than typically developing children? Do individual differences in theory of mind (ToM) understanding among children with ASD predict differences in their behavioral empathy? An original empirical study of 76 children aged 3-12 years (37 with ASD; 39 with typical development) addressed these. Results showed that children with ASD were significantly less empathic, according to their teachers, than typically developing children. However, this was not because of their slower ToM development. Findings showed equally clearly that ToM understanding was unrelated to empathy in children with ASD. The same was true for typically developing children once age and verbal maturity were controlled. Indeed, even the subgroup of older children with ASD in the sample who passed false belief tests were significantly less empathic than younger preschoolers who failed them. Copyright © 2014 ISDN. Published by Elsevier Ltd. All rights reserved.

The ABCs of Challenging Behavior: Understanding Basic Concepts

Science.gov (United States)

Meadan, Hedda; Ayvazo, Shiri; Ostrosky, Michaelene M.

2016-01-01

Many young children engage in challenging behaviors that could have short- and long-term negative effects for both the children and their families. Challenging behaviors refer to "any repeated pattern of behavior, or perception of behavior, that interferes with or is at risk of interfering with optimal learning or engagement in prosocial…

Nonlinear particle-wave kinetics in weakly unstable plasmas

International Nuclear Information System (INIS)

Breizman, B.N.; Berk, H.L.; Pekker, M.S.

1996-01-01

With the motivation to address the behavior of the fusion produced alpha particles in a thermonuclear reactor, a theory is developed for predicting the wave saturation levels and particle transport in weakly unstable systems with a discrete number of modes in the presence of energetic particle sources and sinks. Conditions are established for either steady state or bursting nonlinear scenarios when several modes are excited for cases where there is and there is not resonance overlap. Depending on parameters, the particles can undergo benign relaxation, with only a small fraction of the available free energy released to waves and with no global transport, or the particles can experience rapid global transport caused by a substantial conversion of their free energy into wave energy. When the resonance condition of the particle-wave interaction is varied adiabatically, the particles trapped in a wave are found to form phase space holes or clumps that enhance the particle-wave energy exchange. This mechanism, which has been experimentally observed when there is frequency chirping, causes increased saturation levels of instabilities. If resonance sweeping is imposed externally, the particle free energy can even be tapped in stable systems where background dissipation suppresses linear instability. Externally applied resonance sweeping can be important for alpha particle energy channeling, as well as for understanding fishbone and some Alfven wave instability experiments. Near instability threshold, that is when the destabilizing drive just exceeds the background dissipation, a more sophisticated analysis is developed to predict the correct saturation. To leading order, this problem reduces to an integral equation for the wave amplitude with a temporally non local cubic term. This equation has a self-similar solution that blows-up in a finite time

Can Decision Making Research Provide a Better Understanding of Chemical and Behavioral Addictions?

Science.gov (United States)

Engel, Anzhelika; Cáceda, Ricardo

2015-01-01

We reviewed the cognitive and neurobiological commonalities between chemical and behavioral addictions. Poor impulse control, limited executive function and abnormalities in reward processing are seen in both group of entities. Brain imaging shows consistent abnormalities in frontoparietal regions and the limbic system. In drug addiction, exaggerated risk taking behavior and temporal discounting may reflect an imbalance between a hyperactive mesolimbic and hypoactive executive systems. Several cognitive distortions are found in pathological gambling that seems to harness the brain reward system that has evolved to face situations related to skill, not random chance. Abnormalities in risk assessment and impulsivity are found in variety of eating disorders, in particularly related to eating behavior. Corresponding findings in eating disorder patients include abnormalities in the limbic system, i.e. orbitofrontal cortex (OFC), striatum and insula. Similarly, internet addiction disorder is associated with risky decision making and increased choice impulsivity with corresponding discrepant activation in the dorsolateral prefrontal cortex, OFC, anterior cingulate cortex, caudate and insula. Sexual addictions are in turn associated with exaggerated impulsive choice and suggestive evidence of abnormalities in reward processing. In sum, exploration of executive function and decision making abnormalities in chemical and behavioral addictions may increase understanding in their psychopathology and yield valuable targets for therapeutic interventions.

Rocket-borne double focusing analyzer for particle spectroscopy in the lower magnetosphere

International Nuclear Information System (INIS)

Crifo, J.F.; Prange, R.; Cornic, C.; Salvetat, P.

1976-01-01

We describe a rocket-borne instrument for measurement of the low energy electron and proton distribution function in the magnetosphere. It consists of an optimized programmable electrostatic toroidal analyzer as an energy selector, coupled with an electron multiplier as a particle detector, and of the associated electronics. Much attention has been paid to the experimental calibration of the instrument which gives some understanding of the real behavior of the detector and the way it influences the analyzer properties

Attitudes and Defaults Save Lives and Protect the Environment Jointly and Compensatorily: Understanding the Behavioral Efficacy of Nudges and Other Structural Interventions

Directory of Open Access Journals (Sweden)

Florian G. Kaiser

2014-07-01

Full Text Available A better understanding of when and why nudges (e.g., defaults, visibility or accessibility alterations and other structural behavior-change measures work or fail can help avoid subsequent surprises such as unexpected political opposition. In this paper, we challenge the unilateral focus on structural interventions—which seemingly control people's behavioral decisions—as such a focus ignores the flipside—namely, attitudes or, as they are called in economics, preferences. We argue for a conceptual understanding of individual behavior that views personal attitudes and behavioral costs as its two separate compensatorily effective determinants. This classical understanding was reintroduced into attitude research as the Campbell paradigm. In the logic of the Campbell paradigm, a person's attitude becomes obvious in the face of the behavioral costs the person surmounts. Technically, individual attitudes reveal themselves in a set of cost-dependent transitively ordered performances. Behavioral costs in turn reflect the structural boundary conditions that are relevant as obstructive and/or supportive environmental forces that generically affect a specific behavior. So far, our research on people’s attitudes toward environmental protection has demonstrated that the Campbell paradigm—and thus its conceptual account of individual behavior—holds true for approximately 95% of the people in a given society.

Attitudes and Defaults Save Lives and Protect the Environment Jointly and Compensatorily: Understanding the Behavioral Efficacy of Nudges and Other Structural Interventions

Science.gov (United States)

Kaiser, Florian G.; Arnold, Oliver; Otto, Siegmar

2014-01-01

A better understanding of when and why nudges (e.g., defaults, visibility or accessibility alterations) and other structural behavior-change measures work or fail can help avoid subsequent surprises such as unexpected political opposition. In this paper, we challenge the unilateral focus on structural interventions—which seemingly control people's behavioral decisions—as such a focus ignores the flipside—namely, attitudes or, as they are called in economics, preferences. We argue for a conceptual understanding of individual behavior that views personal attitudes and behavioral costs as its two separate compensatorily effective determinants. This classical understanding was reintroduced into attitude research as the Campbell paradigm. In the logic of the Campbell paradigm, a person's attitude becomes obvious in the face of the behavioral costs the person surmounts. Technically, individual attitudes reveal themselves in a set of cost-dependent transitively ordered performances. Behavioral costs in turn reflect the structural boundary conditions that are relevant as obstructive and/or supportive environmental forces that generically affect a specific behavior. So far, our research on people’s attitudes toward environmental protection has demonstrated that the Campbell paradigm—and thus its conceptual account of individual behavior—holds true for approximately 95% of the people in a given society. PMID:25379277

What's Next for Particle Physics?

Science.gov (United States)

White, Martin

2017-10-01

Following the discovery of the Higgs boson in 2012, particle physics has entered its most exciting and crucial period for over 50 years. In this book, I first summarise our current understanding of particle physics, and why this knowledge is almost certainly incomplete. We will then see that the Large Hadron Collider provides the means to search for the next theory of particle physics by performing precise measurements of the Higgs boson, and by looking directly for particles that can solve current cosmic mysteries such as the nature of dark matter. Finally, I will anticipate the next decade of particle physics by placing the Large Hadron Collider within the wider context of other experiments. The results expected over the next ten years promise to transform our understanding of what the Universe is made of and how it came to be.

Quality Improvement in Hospitals: Identifying and Understanding Behaviors

Directory of Open Access Journals (Sweden)

Lukasz M. Mazur

2012-01-01

Full Text Available Improving operational performance in hospitals is complicated, particularly if process improvement requires complex behavioral changes. Using single-loop and double-loop learning theory as a foundation, the purpose of this research is to empirically uncover key improvement behaviors and the factors that may be associated with such behaviors in hospitals. A two-phased approach was taken to collect data regarding improvement behaviors and associated factors, and data analysis was conducted using methods proposed by grounded theorists. The contributions of this research are twofold. First, five key behaviors related to process improvement are identified, namely Quick Fixing, Initiating, Conforming, Expediting, and Enhancing. Second, based on these observed behaviors, a set of force field diagrams is developed to structure and organize possible factors that are important to consider when attempting to change improvement behaviors. This begins to fill the gap in the knowledge about what factors drive effective improvement efforts in hospital settings.

ESF collection effectiveness, a study in fine particle dynamics

International Nuclear Information System (INIS)

Winegardner, W.K.; Owczarski, P.C.

1985-04-01

The characterization and dynamic behavior of fine particles are the main subjects of an ongoing investigation of the particle collection effectiveness of the engineered safety feature (ESF) systems in nuclear power plants. This investigation is part of a larger study of the release of radionuclides to the environment from such plants during postulated accidents that are severe but extremely unlikely. The ESF systems are installed to prevent the occurrence of severe accidents or mitigate their consequences. Several of these engineered systems can serve as particle collection devices. This report focuses on the analytical models that were developed to predict particle behavior in two systems that were not specifically designed for particle retention: the ice compartments of ice condenser containment systems in Pressurized Water Reactors (PWRs) and the suppression pools of Boiling Water Reactors (BWRs). The following section summarizes the topics considered in the development of models and computer codes for estimating the particle retention effectiveness of these two ESF systems. After the summary this paper describes the two ESF systems in more detail and discusses the behavior of particles in both situations

In situ pH within particle beds of bioactive glasses.

Science.gov (United States)

Zhang, Di; Hupa, Mikko; Hupa, Leena

2008-09-01

The in vitro behavior of three bioactive glasses with seven particle size distributions was studied by measuring the in situ pH inside the particle beds for 48h in simulated body fluid (SBF). After immersion, the surface of the particles was characterized with a field emission scanning electron microscope equipped with an energy-dispersive X-ray analyzer. In addition, the results were compared with the reactions of the same glasses formed as plates. A similar trend in pH as a function of immersion time was observed for all systems. However, the pH inside the particle beds was markedly higher than that in the bulk SBF of the plates. The pH decreased as power functions with increasing particle size, i.e. with decreasing surface area. The in vitro reactivity expressed as layer formation strongly depended on the particle size and glass composition. The average thickness of the total reaction layer decreased with the increase in sample surface area. Well-developed silica and calcium phosphate layers typically observed on glass plates could be detected only on some particles freely exposed to the solution. No distinct reaction layers were observed on the finest particles, possibly because the layers spread out on the large surface area. Differences in the properties of the bulk SBF and the solution inside the particle bed were negligible for particles larger than 800microm. The results enhance our understanding of the in vitro reactions of bioactive glasses in various product forms and sizes.

Applied behavior analysis: understanding and changing behavior in the community-a representative review.

Science.gov (United States)

Luyben, Paul D

2009-01-01

Applied behavior analysis, a psychological discipline, has been characterized as the science of behavior change (Chance, 2006). Research in applied behavior analysis has been published for approximately 40 years since the initial publication of the Journal of Applied Behavior Analysis in 1968. The field now encompasses a wide range of human behavior. Although much of the published research centers on problem behaviors that occur in schools and among people with disabilities, a substantial body of knowledge has emerged in community settings. This article provides a review of the behavioral community research published in the Journal of Applied Behavior Analysis as representative of this work, including research in the areas of home and family, health, safety, community involvement and the environment, recreation and sports, crime and delinquency, and organizations. In the interest of space, research in schools and with people with disabilities has been excluded from this review.

Observing thermomagnetic stability of nonideal magnetite particles

DEFF Research Database (Denmark)

Almeida, Trevor P.; Kasama, Takeshi; Muxworthy, Adrian R.

2014-01-01

The thermomagnetic behavior of remanence-induced magnetite (Fe3O4) particles in the pseudo-single-domain (PSD) size range (similar to 0.1-10 mu m), which dominate the magnetic signature of many rock lithologies, is investigated using off-axis electron holography. Construction of magnetic induction...... of the Fe3O4 grain, in this instance, remains thermally stable close to its unblocking temperature and exhibits a similar in-plane remanent state upon cooling; i.e., the particle is effectively behaving like a uniaxial single-domain particle to temperatures near T-C. Such particles are thought to be robust...... magnetic recorders. It is suggested that evidence for PSD behavior should therefore not preclude paleomagnetic investigation....

DEM Particle Fracture Model

Energy Technology Data Exchange (ETDEWEB)

Zhang, Boning [Univ. of Colorado, Boulder, CO (United States); Herbold, Eric B. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Homel, Michael A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Regueiro, Richard A. [Univ. of Colorado, Boulder, CO (United States)

2015-12-01

An adaptive particle fracture model in poly-ellipsoidal Discrete Element Method is developed. The poly-ellipsoidal particle will break into several sub-poly-ellipsoids by Hoek-Brown fracture criterion based on continuum stress and the maximum tensile stress in contacts. Also Weibull theory is introduced to consider the statistics and size effects on particle strength. Finally, high strain-rate split Hopkinson pressure bar experiment of silica sand is simulated using this newly developed model. Comparisons with experiments show that our particle fracture model can capture the mechanical behavior of this experiment very well, both in stress-strain response and particle size redistribution. The effects of density and packings o the samples are also studied in numerical examples.

Understanding action control of daily walking behavior among dog owners: a community survey

Directory of Open Access Journals (Sweden)

Ryan E. Rhodes

2016-11-01

Full Text Available Abstract Background Walking among dog owners may be a means to achieve health benefits, yet almost half of owners (approximately 30% of households are not regularly walking their dogs. Current research on the correlates of dog walking has generally considered intention as the primary determinant of behavior, yet the intention-behavior relationship is modest. The purpose of this paper was to apply a framework designed to evaluate the intention-behavior gap, known as multi-process action control (M-PAC, to understand daily walking among dog owners. Method A community sample of adult dog owners (N = 227 in Victoria, Canada completed M-PAC measures of motivational (dog and human outcome expectations, affective judgments, perceived capability and opportunity, regulatory (planning, and reflexive (automaticity, identity processes as well as intention to walk and behavior. Results Three intention-behavior profiles emerged: a non-intenders who were not active (26%; n = 59, b unsuccessful intenders who failed to enact their positive intentions (33%; n = 75, and c successful intenders who were active (40%; n = 91. Congruent with M-PAC, a discriminant function analysis showed that affective judgements (r = 0.33, automaticity (r = 0.38, and planning (r = 0.33 distinguished between all three intention-behavior profiles, while identity (r = 0.22 and dog breed size (r = 0.28 differentiated between successful and unsuccessful intenders. Conclusions The majority of dog owners have positive intentions to walk, yet almost half fail to meet these intentions. Interventions focused on affective judgments (e.g., more enjoyable places to walk, behavioral regulation (e.g., setting a concrete plan, habit (e.g., making routines and cues and identity formation (e.g., affirmations of commitment may help overcome difficulties with translating these intentions into action, thus increasing overall levels of walking.

Auroral particles

International Nuclear Information System (INIS)

Evans, D.S.

1987-01-01

The problems concerning the aurora posed prior to the war are now either solved in principle or were restated in a more fundamental form. The pre-war hypothesis concerning the nature of the auroral particles and their energies was fully confirmed, with the exception that helium and oxygen ions were identified as participating in the auroral particle precipitation in addition to the protons. The nature of the near-Earth energization processes affecting auroral particles was clarified. Charged particle trajectories in various electric field geometries were modeled. The physical problems have now moved from determining the nature and geometry of the electric fields, which accelerate charged particles near the Earth, to accounting for the existence of these electric fields as a natural consequence of the solar wind's interaction with Earth. Ultimately the reward in continuing the work in auroral and magnetospheric particle dynamics will be a deeper understanding of the subtleties of classical electricity and magnetism as applied to situations not blessed with well-defined and invariant geometries

Influence of particle surface properties on the dielectric behavior of silica/epoxy nanocomposites

International Nuclear Information System (INIS)

Cheng Lihong; Zheng Liaoying; Li Guorong; Zeng Jiangtao; Yin Qingrui

2008-01-01

Silica/epoxy composites have been widely used in functional electric device applications. Silica nanoparticles, both unmodified and modified with the coupling agent KH-550, were used to prepare epoxy composites. Dielectric measurements showed that nanocomposites exhibit a higher dielectric constant than the control sample, and had more obvious dielectric relaxation characteristics. Results showed that particle surface properties have a profound effect on the dielectric behavior of the nanocomposites. These characteristics are attributed to the local ununiformity of the microstructure caused by the large interface area and the interaction between the filler and the matrix. This phenomenon is explained in terms of prolonging chemical chains created during the curing process. The mechanism is discussed with measurements of X-ray diffraction (XRD) and Fourier transform infrared (FTIR)

Understanding the Behavior of the Oligomeric Fractions During Pyrolysis Oils Upgrading

Science.gov (United States)

Stankovikj, Filip

Fast pyrolysis oils represent most viable renewable sources for production of fuels and chemicals, and they could supplement significant portion of the depleting fossil fuels in near future. Progress on their utilization is impeded by their thermal and storage instability, lack of understanding of their complex composition and behavior during upgrading, including the poorly described water soluble fraction (WS). This work offers two new methodologies for simplified, and sensible description of the pyrolysis oils in terms of functional groups and chemical macro-families, augments our understanding of the composition of the WS, and the behavior of the heavy non-volatile fraction during pyrolysis oils stabilization. The concept of analyzing the volatile and non-volatile fraction in terms of functional groups has been introduced, and the quantification power of spectroscopic techniques (FTIR, 1H-NMR, UV fluorescence) for phenols, carbonyl and carboxyl groups was shown. The FT-ICR-MS van Krevelen diagram revealed the importance of dehydration reactions in pyrolysis oils and the presence of "pyrolytic humins" was hypothesized. For the first time the WS was analyzed with plethora of analytical techniques. This lead to proposition of a new characterization scheme based on functional groups, describing 90-100 wt.% of the bio-oils. The structure of idealized "pyrolytic humin" was further described as a random combination of 3-8 units of dehydrated sugars, coniferyl-type phenols, furans, and carboxylic acids attached on a 2,5-dioxo-6-hydroxyhexanal (DHH) backbone rich in carbonyl groups. TG-FTIR studies resulted in defining rules for fitting pyrolysis oils' DTG curves and assignment of TG residue. This second method is reliable for estimation of water content, light volatiles, WS and WIS. Finally, stabilization of two oils was analyzed through the prism of functional groups. Carbonyl and hydroxyl groups interconverted. The first attempt to follow silent 31P-NMR oxygen was

Standard Practice for Measurement of Mechanical Properties During Charged-Particle Irradiation

CERN Document Server

American Society for Testing and Materials. Philadelphia

1996-01-01

1.1 This practice covers the performance of mechanical tests on materials being irradiated with charged particles. These tests are designed to simulate or provide understanding of, or both, the mechanical behavior of materials during exposure to neutron irradiation. Practices are described that govern the test material, the particle beam, the experimental technique, and the damage calculations. Reference should be made to other ASTM standards, especially Practice E 521. Procedures are described that are applicable to creep and creep rupture tests made in tension and torsion test modes. 1.2 The word simulation is used here in a broad sense to imply an approximation of the relevant neutron irradiation environment. The degree of conformity can range from poor to nearly exact. The intent is to produce a correspondence between one or more aspects of the neutron and charged particle irradiations such that fundamental relationships are established between irradiation or material parameters and the material respons...

The Mysterious Universe - Exploring Our World with Particle Accelerators

Energy Technology Data Exchange (ETDEWEB)

Brau, James E [University of Oregon

2010-11-23

The universe is dark and mysterious, more so than even Einstein imagined. While modern science has established deep understanding of ordinary matter, unidentified elements ("Dark Matter" and "Dark Energy") dominate the structure of the universe, its behavior and its destiny. What are these curious elements? We are now working on answers to these and other challenging questions posed by the universe with experiments at particle accelerators on Earth. Results of this research may revolutionize our view of nature as dramatically as the advances of Einstein and other quantum pioneers one hundred years ago. Professor Brau will explain for the general audience the mysteries, introduce facilities which explore them experimentally and discuss our current understanding of the underlying science. The presentation is at an introductory level, appropriate for anyone interested in physics and astronomy.

Light charged particle emission in the matched reactions 280 MeV 40Ar+27Al and 670 MeV 55Mn+12C: Inclusive studies

International Nuclear Information System (INIS)

Brown, Craig M.; Milosevich, Zoran; Kaplan, Morton; Vardaci, Emanuele; DeYoung, Paul; Whitfield, James P.; Peterson, Donald; Dykstra, Christopher; Karol, Paul J.; McMahan, Margaret A.

1999-01-01

In order to test the statistical model's ability to predict the behavior of relatively light mass systems (A≅67) with large angular momenta, two matched heavy ion nuclear reactions were used to produce 67 Ga * composite nuclei at an excitation energy of 127 MeV. Light charged particles (protons, deuterons, tritons, and α particles) were used as probes to characterize the composite systems and track the deexcitation processes. From these measurements, energy spectra, cross sections, angular distributions, anisotropy ratios, and particle multiplicities were deduced. Measuring many degrees of freedom provides a stringent test for the statistical models. What is found is that models which did well in predicting the behavior of heavy composite systems (A≅150), are unable to simultaneously reproduce energy spectra, angular distributions, and particle multiplicities for the lighter systems (A≅67), where angular momentum plays a dominant role. This implies that more rigorous models and/or additional physics are needed to understand the behavior of the hot, high-spin nuclear matter in this mass region. (c) 1999 The American Physical Society

Influence of arc current and pressure on non-chemical equilibrium air arc behavior

Science.gov (United States)

Yi, WU; Yufei, CUI; Jiawei, DUAN; Hao, SUN; Chunlin, WANG; Chunping, NIU

2018-01-01

The influence of arc current and pressure on the non-chemical equilibrium (non-CE) air arc behavior of a nozzle structure was investigated based on the self-consistent non-chemical equilibrium model. The arc behavior during both the arc burning and arc decay phases were discussed at different currents and different pressures. We also devised the concept of a non-equilibrium parameter for a better understanding of non-CE effects. During the arc burning phase, the increasing current leads to a decrease of the non-equilibrium parameter of the particles in the arc core, while the increasing pressure leads to an increase of the non-equilibrium parameter of the particles in the arc core. During the arc decay phase, the non-CE effect will decrease by increasing the arc burning current and the nozzle pressure. Three factors together—convection, diffusion and chemical reactions—influence non-CE behavior.

Research on the fundamental process of thermal-hydraulic behaviors in severe accident. Vapor film collapse behavior on high temperature particle surface. JAERI's nuclear research promotion program, H10-027-3. Contract research

Energy Technology Data Exchange (ETDEWEB)

Abe, Yutaka [Tsukuba Univ., Institute of Engineering Mechanics and Systems, Tsukuba, Ibaraki (Japan)

2002-03-01

The experimental researches were conducted to study vapor film collapse behavior on high temperature melted core material coarsely mixed in the coolant under the film boiling condition. The film collapse is very important incipient incident of the trigger process for the vapor explosion in sever accident of nuclear reactor. In the experiment, pressure pulse was applied to the vapor film on a high temperature particle surface simulating melted core material to observed microscopic vapor film collapse behavior with a high-speed video camera of 40,500 fps. The particle surface temperature and pressure around the particle were simultaneously measured. The transition of the vapor film thickness and two-dimensional vapor-liquid interface movement and the velocity were estimated with visual data analysis technique, PIV and digital data analysis technique. Furthermore, heat conduction analysis was performed to estimate the vapor-liquid interfacial temperature with the measured temperature and estimated vapor film thickness. As the results, it was clarified that the vapor-liquid interface changed white from transparent view for all the experimental conditions. It is also clarified that the vapor-liquid interfacial temperature decreased under the saturation temperature when the pressure pulse arrive at the particle. The experimental facts indicates the possibility that the vapor film collapse occurs due to the liquid phase homogeneous moving toward the particle drove by the pressure reduction caused by the phase change inside the vapor film. (author)

Fast human behavior analysis for scene understanding

NARCIS (Netherlands)

Lao, W.

2011-01-01

Human behavior analysis has become an active topic of great interest and relevance for a number of applications and areas of research. The research in recent years has been considerably driven by the growing level of criminal behavior in large urban areas and increase of terroristic actions. Also,

Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere.

Science.gov (United States)

Almeida, João; Schobesberger, Siegfried; Kürten, Andreas; Ortega, Ismael K; Kupiainen-Määttä, Oona; Praplan, Arnaud P; Adamov, Alexey; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Dommen, Josef; Donahue, Neil M; Downard, Andrew; Dunne, Eimear; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Guida, Roberto; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Henschel, Henning; Jokinen, Tuija; Junninen, Heikki; Kajos, Maija; Kangasluoma, Juha; Keskinen, Helmi; Kupc, Agnieszka; Kurtén, Theo; Kvashin, Alexander N; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Leppä, Johannes; Loukonen, Ville; Makhmutov, Vladimir; Mathot, Serge; McGrath, Matthew J; Nieminen, Tuomo; Olenius, Tinja; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Riipinen, Ilona; Rissanen, Matti; Rondo, Linda; Ruuskanen, Taina; Santos, Filipe D; Sarnela, Nina; Schallhart, Simon; Schnitzhofer, Ralf; Seinfeld, John H; Simon, Mario; Sipilä, Mikko; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Vaattovaara, Petri; Viisanen, Yrjo; Virtanen, Annele; Vrtala, Aron; Wagner, Paul E; Weingartner, Ernest; Wex, Heike; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Yli-Juuti, Taina; Carslaw, Kenneth S; Kulmala, Markku; Curtius, Joachim; Baltensperger, Urs; Worsnop, Douglas R; Vehkamäki, Hanna; Kirkby, Jasper

2013-10-17

Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid-amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid-dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.

Particle Physics in the LHC Era

CERN Document Server

Bunk, Don

During the past 100 years experimental particle physicists have collected an impressive amount of data. Theorists have also come to understand this data extremely well. It was in the first half of the 20th century the efforts of the early pioneers of quantum mechanics laid the ground work for this understanding: quantum field theory. Through the tireless efforts of researchers during the later half of the 20th century many ideas came together to form what we now call the Standard Model (SM) of particle physics. Finally, it was through the ideas of the renormalization group and effective field theory that the understanding of how the SM fits into a larger framework of particle physics was crystallized. In the past four years the Large Hadron Collider (LHC) has made more precise measurements than ever before. Currently the SM of particle physics is known to have excellent agreement with these measurements. As a result of this agreement with data, the SM continues to play such a central role in modern particle p...

Cloud condensation nuclei and ice nucleation activity of hydrophobic and hydrophilic soot particles.

Science.gov (United States)

Koehler, Kirsten A; DeMott, Paul J; Kreidenweis, Sonia M; Popovicheva, Olga B; Petters, Markus D; Carrico, Christian M; Kireeva, Elena D; Khokhlova, Tatiana D; Shonija, Natalia K

2009-09-28

Cloud condensation nuclei (CCN) activity and ice nucleation behavior (for temperaturesnucleation experiments below -40 degrees C, AEC particles nucleated ice near the expected condition for homogeneous freezing of water from aqueous solutions. In contrast, GTS, TS, and TC1 required relative humidity well in excess of water saturation at -40 degrees C for ice formation. GTS particles required water supersaturation conditions for ice activation even at -51 degrees C. At -51 to -57 degrees C, ice formation in particles with electrical mobility diameter of 200 nm occurred in up to 1 in 1000 TS and TC1 particles, and 1 in 100 TOS particles, at relative humidities below those required for homogeneous freezing in aqueous solutions. Our results suggest that heterogeneous ice nucleation is favored in cirrus conditions on oxidized hydrophilic soot of intermediate polarity. Simple considerations suggest that the impact of hydrophilic soot particles on cirrus cloud formation would be most likely in regions of elevated atmospheric soot number concentrations. The ice formation properties of AEC soot are reasonably consistent with present understanding of the conditions required for aircraft contrail formation and the proportion of soot expected to nucleate under such conditions.

Preliminary Understanding of Surface Plasmon-Enhanced Circular Dichroism Spectroscopy by Single Particle Imaging

Science.gov (United States)

Zhan, Kangshu

Monitoring chiral optical signals of biomolecules as their conformation changes is an important means to study their structures, properties, and functions. Most measurements, however, are ensemble measurements because chiral optical signals from a single biomolecule is often too weak to be detected. In this dissertation, I present my early attempts to study conformational changes of adsorbed proteins by taking advantage of the enhanced electromagnetic (EM) field around a well-designed plasmonic nanofeature. In particular, I discuss the detection of protein adsorption and denaturation on metallic nanoparticles using single particle scattering and CD spectroscopic imaging. Particles of two distinctively different sizes were compared and two different sample protein molecules were studied. A combination of experimental and computational tools was used to simulate and interpret the collected scattering and CD results. The first chapter provides a brief overview of the state-of-art research in CD spectroscopic studies at the single particle level. Three different means to make particles capable of chiral detection are discussed. Various applications beyond single particle imaging are presented to showcase the potential of the described research project, beyond our immediate goals. The second chapter describes my initial characterization of large, metallic, anisotropic nanorods and the establishment of experimental procedures used later for spectrum reconstruction, data visualization and analysis. The physical shape and structure of the particles were imaged by scanning electron microscopy (SEM), the chemical composition by energy dispersive X-ray Spectroscopy (EDS), and the optical properties by darkfield microscopy. An experimental protocol was developed to connect information collected from separate techniques for the same particle, with the aims of discovering any possible structural-property correlation. The reproducibility of the single particle imaging method was

Particles and Patterns in Cellular Automata

International Nuclear Information System (INIS)

Jen, E.; Das, R.; Beasley, C.E.

1999-01-01

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). Our objective has been to develop tools for studying particle interactions in a class of dynamical systems characterized by discreteness, determinism, local interaction, and an inherently parallel form of evolution. These systems can be described by cellular automata (CA) and the behavior we studied has improved our understanding of the nature of patterns generated by CAs, their ability to perform global computations, and their relationship to continuous dynamical systems. We have also developed a rule-table mathematics that enables one to custom-design CA rule tables to generate patterns of specified types, or to perform specified computational tasks

UNDERSTANDING THE ROLE OF BEHAVIOR AND COGNITIONS IN A GROUP EXERCISE SETTING

Directory of Open Access Journals (Sweden)

Kimberley A. Dawson

2004-11-01

Full Text Available The first purpose of the present study examined whether individuals with different exercise behaviors (classified by attendance experienced different or similar cognitive patterns. It was hypothesized that different behavior would lead to different cognitive appraisals. It was predicted that there would be a difference between the three behavioral frequency groups with regard to self-efficacy measures and goal measures. The second purpose of the study was to describe, evaluate and observe whether social factors were associated with participating in exercise in groups. It was hypothesized that those who engage in exercise classes would elicit a social focus. Participants for the study included 39 females who registered in-group fitness classes at a mid-sized university. Attendance over the 10-week course was assessed and participants completed a self-report questionnaire during week seven. The attendance data were used to create 3 exercise frequency groups (regular attenders, sporadic attenders, and dropouts based on ACSM's exercise guidelines. Analysis of Variance (ANOVA, means and frequencies were used to describe the data. There were no significant differences on measures of self-efficacy, goal measures, enjoyment, and external motivation among the three groups (all p's > 0.05. An analysis of the whole group (N=39 discovered a low social focus and high ratings of self-efficacy. Continued research is necessary to investigate the benefit of social support in a group exercise setting, as well as to better understand how self-regulation through self-efficacy and goal factors influences and is influenced by actual behavior.

Brownian Motion of Asymmetric Boomerang Colloidal Particles

Science.gov (United States)

Chakrabarty, Ayan; Konya, Andrew; Wang, Feng; Selinger, Jonathan; Sun, Kai; Wei, Qi-Huo

2014-03-01

We used video microscopy and single particle tracking to study the diffusion and local behaviors of asymmetric boomerang particles in a quasi-two dimensional geometry. The motion is biased towards the center of hydrodynamic stress (CoH) and the mean square displacements of the particles are linear at short and long times with different diffusion coefficients and in the crossover regime it is sub-diffusive. Our model based on Langevin theory shows that these behaviors arise from the non-coincidence of the CoH with the center of the body. Since asymmetric boomerangs represent a class of rigid bodies of more generals shape, therefore our findings are generic and true for any non-skewed particle in two dimensions. Both experimental and theoretical results will be discussed.

The contributions of cognitive neuroscience and neuroimaging to understanding mechanisms of behavior change in addiction.

Science.gov (United States)

Morgenstern, Jon; Naqvi, Nasir H; Debellis, Robert; Breiter, Hans C

2013-06-01

In the last decade, there has been an upsurge of interest in understanding the mechanisms of behavior change (MOBC) and effective behavioral interventions as a strategy to improve addiction-treatment efficacy. However, there remains considerable uncertainty about how treatment research should proceed to address the MOBC issue. In this article, we argue that limitations in the underlying models of addiction that inform behavioral treatment pose an obstacle to elucidating MOBC. We consider how advances in the cognitive neuroscience of addiction offer an alternative conceptual and methodological approach to studying the psychological processes that characterize addiction, and how such advances could inform treatment process research. In addition, we review neuroimaging studies that have tested aspects of neurocognitive theories as a strategy to inform addiction therapies and discuss future directions for transdisciplinary collaborations across cognitive neuroscience and MOBC research. 2013 APA, all rights reserved

Particle characteristics and reduction behavior of synthetic magnetite

International Nuclear Information System (INIS)

Ramadan, Wegdan; Zaki, Mohamed I.; Fouad, Nasr E.; Mekhemer, Gamal A.H.

2014-01-01

Two samples (S1 and S2) of magnetite were synthesized, using two different methods, and characterized by means of X-ray powder diffractometry, infrared and Mössbauer spectroscopy, N 2 sorptiometry and electron microscopy. Particles of sample-S1 were found to be loosely agglomerated, micro-sized spheroids (200–350 nm) composed almost solely of highly aggregated (fused) crystallites (size averaged at 35 nm) of cubic-Fe 3 O 4 . In contrast, particles of sample-S2 were strongly agglomerated, nano-sized spheroids (25–30 nm) composed of slightly aggregated crystallites (size averaged at 11 nm) of cubic-Fe 3 O 4 and noncrystalline domains made-up of FeO(OH) species. Temperature-programed reduction (TPR) profiles obtained for the two samples were similar in monitoring two peaks at >450 °C assignable to a two-step reduction of Fe 3 O 4 (→FeO→Fe), but different in monitoring a peak at 3 O 4 ) contained in sample-S2. However, curve fitting analysis of the TPR profiles and molecular stoichiometry calculations based on amounts of hydrogen consumed revealed that the two-step reduction of Fe 3 O 4 is not straightforward. That is by resolving two consecutive pathways for each step and, hence, nonstoichiometric intermediate products whose composition was found to be critically controlled by the composition of the reducing gas atmosphere (5 or 80% H 2 /N 2 ) and characteristics of the starting sample particles (chemical and phase composition, and, but to lesser extents, the agglomeration and average size). - Highlights: • Nano or micro, pure Fe 3 O 4 particles are H 2 -reduced in two steps (→FeO→Fe) at >450 °C. • FeO(OH)-impure particles exhibit a third reduction step (FeO(OH)→Fe 3 O 4 ) at 3 O 4 reduction steps resolves two consecutive pathways. • Moreover, various nonstoichiometric reduction intermediate products are genesized

Human behavior understanding in networked sensing theory and applications of networks of sensors

CERN Document Server

Spagnolo, Paolo; Distante, Cosimo

2014-01-01

This unique text/reference provides a broad overview of both the technical challenges in sensor network development, and the real-world applications of distributed sensing. Important aspects of distributed computing in large-scale networked sensor systems are analyzed in the context of human behavior understanding, including such topics as systems design tools and techniques, in-network signals, and information processing. Additionally, the book examines a varied range of application scenarios, covering surveillance, indexing and retrieval, patient care, industrial safety, social and ambient

Engineered nano particles: Nature, behavior, and effect on the environment.

Science.gov (United States)

Goswami, Linee; Kim, Ki-Hyun; Deep, Akash; Das, Pallabi; Bhattacharya, Satya Sundar; Kumar, Sandeep; Adelodun, Adedeji A

2017-07-01

Increased application of engineered nano particles (ENPs) in production of various appliances and consumer items is increasing their presence in the natural environment. Although a wide variety of nano particles (NPs) are ubiquitously dispersed in ecosystems, risk assessment guidelines to describe their ageing, direct exposure, and long-term accumulation characteristics are poorly developed. In this review, we describe what is known about the life cycle of ENPs and their impact on natural systems and examine if there is a cohesive relationship between their transformation processes and bio-accessibility in various food chains. Different environmental stressors influence the fate of these particles in the environment. Composition of solid media, pore size, solution chemistry, mineral composition, presence of natural organic matter, and fluid velocity are some environmental stressors that influence the transformation, transport, and mobility of nano particles. Transformed nano particles can reduce cell viability, growth and morphology, enhance oxidative stress, and damage DNA in living organisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere

CERN Document Server

Almeida, João; Kürten, Andreas; Ortega, Ismael K; Kupiainen-Määttä, Oona; Praplan, Arnaud P; Adamov, Alexey; Amorim, Antonio; Bianchi, Federico; Breitenlechner, Martin; David, André; Dommen, Josef; Donahue, Neil M; Downard, Andrew; Dunne, Eimear; Duplissy, Jonathan; Ehrhart, Sebastian; Flagan, Richard C; Franchin, Alessandro; Guida, Roberto; Hakala, Jani; Hansel, Armin; Heinritzi, Martin; Henschel, Henning; Jokinen, Tuija; Junninen, Heikki; Kajos, Maija; Kangasluoma, Juha; Keskinen, Helmi; Kupc, Agnieszka; Kurtén, Theo; Kvashin, Alexander N; Laaksonen, Ari; Lehtipalo, Katrianne; Leiminger, Markus; Leppä, Johannes; Loukonen, Ville; Makhmutov, Vladimir; Mathot, Serge; McGrath, Matthew J; Nieminen, Tuomo; Olenius, Tinja; Onnela, Antti; Petäjä, Tuukka; Riccobono, Francesco; Riipinen, Ilona; Rissanen, Matti; Rondo, Linda; Ruuskanen, Taina; Santos, Filipe D; Sarnela, Nina; Schallhart, Simon; Schnitzhofer, Ralf; Seinfeld, John H; Simon, Mario; Sipilä, Mikko; Stozhkov, Yuri; Stratmann, Frank; Tomé, Antonio; Tröstl, Jasmin; Tsagkogeorgas, Georgios; Vaattovaara, Petri; Viisanen, Yrjo; Virtanen, Annele; Vrtala, Aron; Wagner, Paul E; Weingartner, Ernest; Wex, Heike; Williamson, Christina; Wimmer, Daniela; Ye, Penglin; Yli-Juuti, Taina; Carslaw, Kenneth S; Kulmala, Markku; Curtius, Joachim; Baltensperger, Urs; Vehkamaki, Hanna; Kirkby, Jasper

2013-01-01

Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei. Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes. Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases. However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere. It is thought that amines may enhance nucleation, but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates ...

Some features of particle orbit behavior in LHD configurations

International Nuclear Information System (INIS)

Shishkin, A.A.; Watanabe, K.Y.; Yamazaki, K.; Motojima, O.; Grekov, D.L.; Smirnova, M.S.; Zolotukhin, A.V.

1993-03-01

Localizations of helically trapped particle losses on the last closed magnetic surface in different LHD configurations are studied. The effects of electric field, finite β and bootstrap current are taken into account. It is shown that the angular location of the helically trapped particle losses may be controlled by the change of vertical field coil currents. (author)

Merging for Particle-Mesh Complex Particle Kinetic Modeling of the Multiple Plasma Beams

Science.gov (United States)

Lipatov, Alexander S.

2011-01-01

We suggest a merging procedure for the Particle-Mesh Complex Particle Kinetic (PMCPK) method in case of inter-penetrating flow (multiple plasma beams). We examine the standard particle-in-cell (PIC) and the PMCPK methods in the case of particle acceleration by shock surfing for a wide range of the control numerical parameters. The plasma dynamics is described by a hybrid (particle-ion-fluid-electron) model. Note that one may need a mesh if modeling with the computation of an electromagnetic field. Our calculations use specified, time-independent electromagnetic fields for the shock, rather than self-consistently generated fields. While a particle-mesh method is a well-verified approach, the CPK method seems to be a good approach for multiscale modeling that includes multiple regions with various particle/fluid plasma behavior. However, the CPK method is still in need of a verification for studying the basic plasma phenomena: particle heating and acceleration by collisionless shocks, magnetic field reconnection, beam dynamics, etc.

Effects of Particles Collision on Separating Gas–Particle Two-Phase Turbulent Flows

KAUST Repository

Sihao, L. V.

2013-10-10

A second-order moment two-phase turbulence model incorporating a particle temperature model based on the kinetic theory of granular flow is applied to investigate the effects of particles collision on separating gas–particle two-phase turbulent flows. In this model, the anisotropy of gas and solid phase two-phase Reynolds stresses and their correlation of velocity fluctuation are fully considered using a presented Reynolds stress model and the transport equation of two-phase stress correlation. Experimental measurements (Xu and Zhou in ASME-FED Summer Meeting, San Francisco, Paper FEDSM99-7909, 1999) are used to validate this model, source codes and prediction results. It showed that the particles collision leads to decrease in the intensity of gas and particle vortices and takes a larger effect on particle turbulent fluctuations. The time-averaged velocity, the fluctuation velocity of gas and particle phase considering particles colli-sion are in good agreement with experimental measurements. Particle kinetic energy is always smaller than gas phase due to energy dissipation from particle collision. Moreover, axial– axial and radial–radial fluctuation velocity correlations have stronger anisotropic behaviors. © King Fahd University of Petroleum and Minerals 2013

Particle acceleration through the resonance of high magnetic field and high frequency electromagnetic wave

International Nuclear Information System (INIS)

Hong, Liu; He, X.T.; Chen, S.G.; Zhang, W.Y.; He, X.T.; Hong, Liu

2004-01-01

We propose a new particle acceleration mechanism. Electrons can be accelerated to relativistic energy within a few electromagnetic wave cycles through the mechanism which is named electromagnetic and magnetic field resonance acceleration (EMRA). We find that the electron acceleration depends not only on the electromagnetic wave intensity, but also on the ratio between electron Larmor frequency and electromagnetic wave frequency. As the ratio approaches to unity, a clear resonance peak is observed, corresponding to the EMRA. Near the resonance regime, the strong magnetic fields still affect the electron acceleration dramatically. We derive an approximate analytical solution of the relativistic electron energy in adiabatic limit, which provides a full understanding of this phenomenon. In typical parameters of pulsar magnetospheres, the mechanism allows particles to increase their energies through the resonance of high magnetic field and high frequency electromagnetic wave in each electromagnetic wave period. The energy spectra of the accelerated particles exhibit the synchrotron radiation behavior. These can help to understand the remaining emission of high energy electron from radio pulsar within supernova remnant. The other potential application of our theory in fast ignition scheme of inertial confinement fusion is also discussed. (authors)

Rheological behavior study of a clay-polymer mixture: effects of the polymer addition

International Nuclear Information System (INIS)

Benchabane, A.

2006-11-01

The aim of the present work is to establish a bibliographical synthesis on the microstructure, the colloidal and rheological characterization of bentonite suspensions with and without polymer/surfactant addition; to lead to a rheological characterization of clay-additive mixtures and to understand the interaction between the clay particles and polymer/surfactants. Different experimental measurements: rheology, particle sizing, and x-ray diffraction were used to study the rheological character of the water-bentonite-anionic additive mixtures (CMC, SDS, xanthane) as well as the nature of the particle-particle interactions and particle-additive. The modeling part led to the adoption of Tiu and Boger's model to predict the thixotropy of the bentonite suspensions without additive. Thus, a new model is proposed with physical parameters for a better correlation of the rheological behavior of the various studied mixtures. (author)

Advances in Understanding Energy Consumption Behavior and the Governance of Its Change – Outline of an Integrated Framework

Energy Technology Data Exchange (ETDEWEB)

Burger, Paul, E-mail: paul.burger@unibas.ch [Sustainability Research Group, University of Basel, Basel (Switzerland); Bezençon, Valéry [Enterprise Institute, University of Neuchâtel, Neuchâtel (Switzerland); Bornemann, Basil [Sustainability Research Group, University of Basel, Basel (Switzerland); Brosch, Tobias [Department of Psychology, Swiss Center for Affective Sciences, University of Geneva, Geneva (Switzerland); Carabias-Hütter, Vicente [Institute of Sustainable Development, Zurich University of Applied Sciences, Winterthur (Switzerland); Farsi, Mehdi [Institute of Economic Research, University of Neuchâtel, Neuchâtel (Switzerland); Hille, Stefanie Lena [Institute for Economy and the Environment, University of St. Gallen, St. Gallen (Switzerland); Moser, Corinne [Institute of Sustainable Development, Zurich University of Applied Sciences, Winterthur (Switzerland); Ramseier, Céline [Center for Energy Policy and Economics, ETH Zurich, Zurich (Switzerland); Samuel, Robin [Institute of Sociology, University of Bern, Bern (Switzerland); Social Research and Methodology Group, University of Basel, Basel (Switzerland); Sander, David [Department of Psychology, Swiss Center for Affective Sciences, University of Geneva, Geneva (Switzerland); Schmidt, Stephan; Sohre, Annika [Sustainability Research Group, University of Basel, Basel (Switzerland); Volland, Benjamin [Institute of Economic Research, University of Neuchâtel, Neuchâtel (Switzerland)

2015-06-15

Transforming today’s energy systems in industrialized countries requires a substantial reduction of the total energy consumption at the individual level. Selected instruments have been found to be effective in changing people’s behavior in single domains. However, the so far weak success story on reducing overall energy consumption indicates that our understanding of the determining factors of individual energy consumption as well as of its change is far from being conclusive. Among others, the scientific state of the art is dominated by analyzing single domains of consumption and by neglecting embodied energy. It also displays strong disciplinary splits and the literature often fails to distinguish between explaining behavior and explaining change of behavior. Moreover, there are knowledge gaps regarding the legitimacy and effectiveness of the governance of individual consumption behavior and its change. Against this backdrop, the aim of this paper is to establish an integrated interdisciplinary framework that offers a systematic basis for linking the different aspects in research on energy related consumption behavior, thus paving the way for establishing a better evidence base to inform societal actions. The framework connects the three relevant analytical aspects of the topic in question: (1) it systematically and conceptually frames the objects, i.e., the energy consumption behavior and its change (explananda); (2) it structures the factors that potentially explain the energy consumption behavior and its change (explanantia); (3) it provides a differentiated understanding of change inducing interventions in terms of governance. Based on the existing states of the art approaches from different disciplines within the social sciences, the proposed framework is supposed to guide interdisciplinary empirical research.

Advances in Understanding Energy Consumption Behavior and the Governance of Its Change – Outline of an Integrated Framework

International Nuclear Information System (INIS)

Burger, Paul; Bezençon, Valéry; Bornemann, Basil; Brosch, Tobias; Carabias-Hütter, Vicente; Farsi, Mehdi; Hille, Stefanie Lena; Moser, Corinne; Ramseier, Céline; Samuel, Robin; Sander, David; Schmidt, Stephan; Sohre, Annika; Volland, Benjamin

2015-01-01

Transforming today’s energy systems in industrialized countries requires a substantial reduction of the total energy consumption at the individual level. Selected instruments have been found to be effective in changing people’s behavior in single domains. However, the so far weak success story on reducing overall energy consumption indicates that our understanding of the determining factors of individual energy consumption as well as of its change is far from being conclusive. Among others, the scientific state of the art is dominated by analyzing single domains of consumption and by neglecting embodied energy. It also displays strong disciplinary splits and the literature often fails to distinguish between explaining behavior and explaining change of behavior. Moreover, there are knowledge gaps regarding the legitimacy and effectiveness of the governance of individual consumption behavior and its change. Against this backdrop, the aim of this paper is to establish an integrated interdisciplinary framework that offers a systematic basis for linking the different aspects in research on energy related consumption behavior, thus paving the way for establishing a better evidence base to inform societal actions. The framework connects the three relevant analytical aspects of the topic in question: (1) it systematically and conceptually frames the objects, i.e., the energy consumption behavior and its change (explananda); (2) it structures the factors that potentially explain the energy consumption behavior and its change (explanantia); (3) it provides a differentiated understanding of change inducing interventions in terms of governance. Based on the existing states of the art approaches from different disciplines within the social sciences, the proposed framework is supposed to guide interdisciplinary empirical research.

Determining size-specific emission factors for environmental tobacco smoke particles

Energy Technology Data Exchange (ETDEWEB)

Klepeis, Neil E.; Apte, Michael G.; Gundel, Lara A.; Sextro, Richard G.; Nazaroff, William W.

2002-07-07

Because size is a major controlling factor for indoor airborne particle behavior, human particle exposure assessments will benefit from improved knowledge of size-specific particle emissions. We report a method of inferring size-specific mass emission factors for indoor sources that makes use of an indoor aerosol dynamics model, measured particle concentration time series data, and an optimization routine. This approach provides--in addition to estimates of the emissions size distribution and integrated emission factors--estimates of deposition rate, an enhanced understanding of particle dynamics, and information about model performance. We applied the method to size-specific environmental tobacco smoke (ETS) particle concentrations measured every minute with an 8-channel optical particle counter (PMS-LASAIR; 0.1-2+ micrometer diameters) and every 10 or 30 min with a 34-channel differential mobility particle sizer (TSI-DMPS; 0.01-1+ micrometer diameters) after a single cigarette or cigar was machine-smoked inside a low air-exchange-rate 20 m{sup 3} chamber. The aerosol dynamics model provided good fits to observed concentrations when using optimized values of mass emission rate and deposition rate for each particle size range as input. Small discrepancies observed in the first 1-2 hours after smoking are likely due to the effect of particle evaporation, a process neglected by the model. Size-specific ETS particle emission factors were fit with log-normal distributions, yielding an average mass median diameter of 0.2 micrometers and an average geometric standard deviation of 2.3 with no systematic differences between cigars and cigarettes. The equivalent total particle emission rate, obtained integrating each size distribution, was 0.2-0.7 mg/min for cigars and 0.7-0.9 mg/min for cigarettes.

Adhesion of nano-sized particles to the surface of bacteria: mechanistic study with the extended DLVO theory.

Science.gov (United States)

Hwang, Geelsu; Ahn, Ik-Sung; Mhin, Byung Jin; Kim, Ju-Young

2012-09-01

Due to the increasing production and application of nanoparticles, their release into the environment would be inevitable, which requires a better understanding of their fate in the environment. When considering their toxic behavior or biodegradation as their fate, their adhesion to the cell surface must be the first step to be thoroughly studied. In this study, nano-sized polymeric particles of urethane acrylate with various hydrophobicity and ionic properties were synthesized as model nanoparticles, and their adhesion to Pseudomonas putida strains was monitored. The higher hydrophobicity and positive charge density on the particle surface exhibited the larger adhesion to the bacteria, whereas negative charge density on the particle hindered their adhesion to the bacteria, albeit high hydrophobicity of particle. These observations were successfully explained with the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. Copyright © 2012 Elsevier B.V. All rights reserved.

Interaction of Multiple Particles with a Solidification Front: From Compacted Particle Layer to Particle Trapping.

Science.gov (United States)

Saint-Michel, Brice; Georgelin, Marc; Deville, Sylvain; Pocheau, Alain

2017-06-13

The interaction of solidification fronts with objects such as particles, droplets, cells, or bubbles is a phenomenon with many natural and technological occurrences. For an object facing the front, it may yield various fates, from trapping to rejection, with large implications regarding the solidification pattern. However, whereas most situations involve multiple particles interacting with each other and the front, attention has focused almost exclusively on the interaction of a single, isolated object with the front. Here we address experimentally the interaction of multiple particles with a solidification front by performing solidification experiments of a monodisperse particle suspension in a Hele-Shaw cell with precise control of growth conditions and real-time visualization. We evidence the growth of a particle layer ahead of the front at a close-packing volume fraction, and we document its steady-state value at various solidification velocities. We then extend single-particle models to the situation of multiple particles by taking into account the additional force induced on an entering particle by viscous friction in the compacted particle layer. By a force balance model this provides an indirect measure of the repelling mean thermomolecular pressure over a particle entering the front. The presence of multiple particles is found to increase it following a reduction of the thickness of the thin liquid film that separates particles and front. We anticipate the findings reported here to provide a relevant basis to understand many complex solidification situations in geophysics, engineering, biology, or food engineering, where multiple objects interact with the front and control the resulting solidification patterns.

Characterization, origin and aggregation behavior of colloids in eutrophic shallow lake.

Science.gov (United States)

Xu, Huacheng; Xu, Mengwen; Li, Yani; Liu, Xin; Guo, Laodong; Jiang, Helong

2018-05-31

Stability of colloidal particles contributes to the turbidity in the water column, which significantly influences water quality and ecological functions in aquatic environments especially shallow lakes. Here we report characterization, origin and aggregation behavior of aquatic colloids, including natural colloidal particles (NCPs) and total inorganic colloidal particles (TICPs), in a highly turbid shallow lake, via field observations, simulation experiments, ultrafiltration, spectral and microscopic, and light scattering techniques. The colloidal particles were characterized with various shapes (spherical, polygonal and elliptical) and aluminum-, silicon-, and ferric-containing mineralogical structures, with a size range of 20-200 nm. The process of sediment re-suspension under environmentally relevant conditions contributed 78-80% of TICPs and 54-55% of NCPs in Lake Taihu, representing an important source of colloids in the water column. Both mono- and divalent electrolytes enhanced colloidal aggregation, while a reverse trend was observed in the presence of natural organic matter (NOM). The influence of NOM on colloidal stability was highly related to molecular weight (MW) properties with the high MW fraction exhibiting higher stability efficiency than the low MW counterparts. However, the MW-dependent aggregation behavior for NCPs was less significant than that for TICPs, implying that previous results on colloidal behavior using model inorganic colloids alone should be reevaluated. Further studies are needed to better understand the mobility/stability and transformation of aquatic colloids and their role in governing the fate and transport of pollutants in natural waters. Copyright © 2018. Published by Elsevier Ltd.

Particle accelerator; the Universe machine

CERN Multimedia

Yurkewicz, Katie

2008-01-01

"In summer 2008, scientists will switch on one of the largest machines in the world to search for the smallest of particle. CERN's Large Hadron Collider particle accelerator has the potential to chagne our understanding of the Universe."

Neurohormones, Brain, and Behavior: A Comparative Approach to Understanding Rapid Neuroendocrine Action.

Science.gov (United States)

Calisi, Rebecca M; Saldanha, Colin J

2015-08-01

The definition of a hormone has been in part delineated by its journey to distant receptor targets. Following activation of a receptor, a subsequent reaction facilitates the regulation of physiology and, ultimately, behavior. However, a growing number of studies report that hormones can influence these events at a previously underappreciated high speed. With the potential to act as neurotransmitters, the definition of a hormone and its mechanisms of action are evolving. In this symposium, we united scientists who use contemporary molecular, electrophysiological, and biochemical approaches to study aspects of rapid hormone action in a broad array of systems across different levels of biological organization. What emerged was an overwhelming consensus that the use of integrative and comparative approaches fuels discovery and increases our understanding of de novo hormone synthesis, local actions of neurohormones, and subsequent effects on neuroplasticity and behavior. © The Author 2015. Published by Oxford University Press on behalf of the Society for Integrative and Comparative Biology. All rights reserved. For permissions please email: journals.permissions@oup.com.

RESIDENCE TIMES OF PARTICLES IN DIFFUSIVE PROTOPLANETARY DISK ENVIRONMENTS. I. VERTICAL MOTIONS

International Nuclear Information System (INIS)

Ciesla, F. J.

2010-01-01

The chemical and physical evolution of primitive materials in protoplanetary disks are determined by the types of environments they are exposed to and their residence times within each environment. Here, a method for calculating representative paths of materials in diffusive protoplanetary disks is developed and applied to understanding how the vertical trajectories that particles take impact their overall evolution. The methods are general enough to be applied to disks with uniform diffusivity, the so-called constant-α cases, and disks with a spatially varying diffusivity, such as expected in 'layered-disks'. The average long-term dynamical evolution of small particles and gaseous molecules is independent of the specific form of the diffusivity in that they spend comparable fractions of their lifetimes at different heights in the disk. However, the paths that individual particles and molecules take depend strongly on the form of the diffusivity leading to a different range of behavior of particles in terms of deviations from the mean. As temperatures, gas densities, chemical abundances, and photon fluxes will vary with height in protoplanetary disks, the different paths taken by primitive materials will lead to differences in their chemical and physical evolution. Examples of differences in gas phase chemistry and photochemistry are explored here. The methods outlined here provide a powerful tool that can be integrated with chemical models to understand the formation and evolution of primitive materials in protoplanetary disks on timescales of 10 5 -10 6 years.

Particle characteristics and reduction behavior of synthetic magnetite

Energy Technology Data Exchange (ETDEWEB)

Ramadan, Wegdan [Physics Department, Faculty of Science, Alexandria University, Alexandria 21511 (Egypt); Zaki, Mohamed I., E-mail: mizaki@link.net [Chemistry Department, Faculty of Science, Minia University, El-Minia 61519 (Egypt); Fouad, Nasr E.; Mekhemer, Gamal A.H. [Chemistry Department, Faculty of Science, Minia University, El-Minia 61519 (Egypt)

2014-04-15

Two samples (S1 and S2) of magnetite were synthesized, using two different methods, and characterized by means of X-ray powder diffractometry, infrared and Mössbauer spectroscopy, N{sub 2} sorptiometry and electron microscopy. Particles of sample-S1 were found to be loosely agglomerated, micro-sized spheroids (200–350 nm) composed almost solely of highly aggregated (fused) crystallites (size averaged at 35 nm) of cubic-Fe{sub 3}O{sub 4}. In contrast, particles of sample-S2 were strongly agglomerated, nano-sized spheroids (25–30 nm) composed of slightly aggregated crystallites (size averaged at 11 nm) of cubic-Fe{sub 3}O{sub 4} and noncrystalline domains made-up of FeO(OH) species. Temperature-programed reduction (TPR) profiles obtained for the two samples were similar in monitoring two peaks at >450 °C assignable to a two-step reduction of Fe{sub 3}O{sub 4} (→FeO→Fe), but different in monitoring a peak at<450 °C only for the reduction of FeO(OH) (→Fe{sub 3}O{sub 4}) contained in sample-S2. However, curve fitting analysis of the TPR profiles and molecular stoichiometry calculations based on amounts of hydrogen consumed revealed that the two-step reduction of Fe{sub 3}O{sub 4} is not straightforward. That is by resolving two consecutive pathways for each step and, hence, nonstoichiometric intermediate products whose composition was found to be critically controlled by the composition of the reducing gas atmosphere (5 or 80% H{sub 2}/N{sub 2}) and characteristics of the starting sample particles (chemical and phase composition, and, but to lesser extents, the agglomeration and average size). - Highlights: • Nano or micro, pure Fe{sub 3}O{sub 4} particles are H{sub 2}-reduced in two steps (→FeO→Fe) at >450 °C. • FeO(OH)-impure particles exhibit a third reduction step (FeO(OH)→Fe{sub 3}O{sub 4}) at <450 °C. • FeO disproportion and related autocatalytic effects complicate the reduction course. • Consequently, each of the Fe{sub 3}O{sub 4

Milling Behavior of Matrix Graphite Powders with Different Binder Materials in HTGR Fuel Element Fabrication: I. Variation in Particle Size Distribution

International Nuclear Information System (INIS)

Lee, Young Woo; Cho, Moon Sung

2011-01-01

The fuel element for HTGR is manufactured by mixing coated fuel particles with matrix graphite powder and forming into either pebble type or cylindrical type compacts depending on their use in different HTGR cores. The coated fuel particle, the so-called TRISO particle, consists of 500-μm spherical UO 2 particles coated with the low density buffer Pyrolytic Carbon (PyC) layer, the inner and outer high density PyC layer and SiC layer sandwiched between the two inner and outer PyC layers. The coated TRISO particles are mixed with a matrix graphite powder properly prepared and pressed into a spherical shape or a cylindrical compact finally heat-treated at about 1900 .deg. C. These fuel elements can have different sizes and forms of compact. The basic steps for manufacturing a fuel element include preparation of graphite matrix powder, overcoating the fuel particles, mixing the fuel particles with a matrix powder, carbonizing green compact, and the final high-temperature heat treatment of the carbonized fuel compact. In order to develop a fuel compact fabrication technology, it is important to develop a technology to prepare the matrix graphite powder (MGP) with proper characteristics, which has a strong influence on further steps and the material properties of fuel element. In this work, the milling behavior of matrix graphite powder mixture with different binder materials and their contents was investigated by analyzing the change in particle size distribution with different milling time

An Integrative Model for Understanding Team Organizational Citizenship Behavior: Its Antecedents and Consequences for Educational Teams

Science.gov (United States)

Somech, Anit; Khotaba, Soha

2017-01-01

Purpose: The purpose of this paper is to use a model to broaden the understanding of the organizational citizenship behavior (OCB) phenomenon in educational teams and examines team OCB's mediating role in the relation of the contextual variables of team justice climate (distributive justice, procedural justice, interpersonal justice) to team…

Understanding particle size and distance driven competition of interparticle interactions and effective single-particle anisotropy

Czech Academy of Sciences Publication Activity Database

Pacáková, Barbara; Mantlíková, Alice; Nižňanský, D.; Kubíčková, Simona; Vejpravová, Jana

2016-01-01

Roč. 28, č. 20 (2016), 1-11, č. článku 206004. ISSN 0953-8984 R&D Projects: GA ČR(CZ) GA15-01953S Institutional support: RVO:68378271 Keywords : magnetic nanoparticles * single-particle anisotropy * dipolar energy Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.649, year: 2016

Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

Science.gov (United States)

Jing, Bo; Wang, Zhen; Tan, Fang; Guo, Yucong; Tong, Shengrui; Wang, Weigang; Zhang, Yunhong; Ge, Maofa

2018-04-01

While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO3)2) and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA). The nitrate salt / organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH), the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

Hygroscopic behavior of atmospheric aerosols containing nitrate salts and water-soluble organic acids

Directory of Open Access Journals (Sweden)

B. Jing

2018-04-01

Full Text Available While nitrate salts have critical impacts on environmental effects of atmospheric aerosols, the effects of coexisting species on hygroscopicity of nitrate salts remain uncertain. The hygroscopic behaviors of nitrate salt aerosols (NH4NO3, NaNO3, Ca(NO32 and their internal mixtures with water-soluble organic acids were determined using a hygroscopicity tandem differential mobility analyzer (HTDMA. The nitrate salt ∕ organic acid mixed aerosols exhibit varying phase behavior and hygroscopic growth depending upon the type of components in the particles. Whereas pure nitrate salt particles show continuous water uptake with increasing relative humidity (RH, the deliquescence transition is still observed for ammonium nitrate particles internally mixed with organic acids such as oxalic acid and succinic acid with a high deliquescence point. The hygroscopicity of submicron aerosols containing sodium nitrate and an organic acid is also characterized by continuous growth, indicating that sodium nitrate tends to exist in a liquid-like state under dry conditions. It is observed that in contrast to the pure components, the water uptake is hindered at low and moderate RH for calcium nitrate particles containing malonic acid or phthalic acid, suggesting the potential effects of mass transfer limitation in highly viscous mixed systems. Our findings improve fundamental understanding of the phase behavior and water uptake of nitrate-salt-containing aerosols in the atmospheric environment.

Understanding caregivers' intentions for their child to walk to school: Further application of the theory of planned behavior.

Science.gov (United States)

Schuster, Lisa; Kubacki, Krzysztof; Rundle-Thiele, Sharyn

2016-01-01

Increases in childhood obesity have coincided with declines in active transportation to school. This research builds on largely atheoretical extant literature examining factors that influence walk-to-school behavior through application of the theory of planned behavior (TPB). Understanding caregivers' decision for their child to walk to/from school is key to developing interventions to promote this cost-effective and accessible health behavior. The results from an online survey of 512 caregivers provide support for the TPB, highlighting the important role of subjective norms. This suggests marketers should nurture caregivers' perception that important others approve of walking to school.

Getting angry matters: Going beyond perspective taking and empathic concern to understand bystanders' behavior in bullying.

Science.gov (United States)

Pozzoli, Tiziana; Gini, Gianluca; Thornberg, Robert

2017-12-01

The present study examined the relations between different empathic dimensions and bystanders' behavior in bullying. Specifically, the indirect effects of empathic concern and perspective taking via empathic anger on defending and passive bystanding were tested in a sample of Italian young adolescents (N = 398; M age  = 12 years, 3 months, 47.2% girls). Path analysis confirmed the direct and indirect effects, via empathic anger, of empathic concern and perspective taking on bystanders' behavior, with the exception of the direct association between perspective taking and passive bystanding that was not significant. Our findings suggest that considering empathic anger together with empathic concern and perspective taking could help researchers to better understand the links between empathic dispositions and bystanders' behavior in bullying. Copyright © 2017. Published by Elsevier Ltd.

Understanding social and behavioral drivers and impacts of air quality sensor use.

Science.gov (United States)

Hubbell, Bryan J; Kaufman, Amanda; Rivers, Louie; Schulte, Kayla; Hagler, Gayle; Clougherty, Jane; Cascio, Wayne; Costa, Dan

2018-04-15

Lower-cost air quality sensors (hundreds to thousands of dollars) are now available to individuals and communities. This technology is undergoing a rapid and fragmented evolution, resulting in sensors that have uncertain data quality, measure different air pollutants and possess a variety of design attributes. Why and how individuals and communities choose to use sensors is arguably influenced by social context. For example, community experiences with environmental exposures and health effects and related interactions with industry and government can affect trust in traditional air quality monitoring. To date, little social science research has been conducted to evaluate why or how sensors, and sensor data, are used by individuals and communities, or how the introduction of sensors changes the relationship between communities and air quality managers. This commentary uses a risk governance/responsible innovation framework to identify opportunities for interdisciplinary research that brings together social scientists with air quality researchers involved in developing, testing, and deploying sensors in communities. Potential areas for social science research include communities of sensor users; drivers for use of sensors and sensor data; behavioral, socio-political, and ethical implications of introducing sensors into communities; assessing methods for communicating sensor data; and harnessing crowdsourcing capabilities to analyze sensor data. Social sciences can enhance understanding of perceptions, attitudes, behaviors, and other human factors that drive levels of engagement with and trust in different types of air quality data. New transdisciplinary research bridging social sciences, natural sciences, engineering, and design fields of study, and involving citizen scientists working with professionals from a variety of backgrounds, can increase our understanding of air sensor technology use and its impacts on air quality and public health. Published by Elsevier B.V.

Hysteretic behavior of soft magnetic elastomer composites

Energy Technology Data Exchange (ETDEWEB)

Krautz, Maria; Werner, David [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Schrödner, Mario [Thuringian Institute of Textile and Plastics Research e.V., Breitscheidstraße 97, D-07407 Rudolstadt (Germany); Funk, Alexander [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Jantz, Alexander; Popp, Jana [Thuringian Institute of Textile and Plastics Research e.V., Breitscheidstraße 97, D-07407 Rudolstadt (Germany); Eckert, Jürgen [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany); Erich Schmid Institute of Materials Science, Austrian Academy of Sciences, Jahnstraße 12, A-8700 Leoben (Austria); Department of Materials Physics, Montanuniversität Leoben, Jahnstraße 12, A-8700 Leoben (Austria); Waske, Anja [Institute for Complex Materials, IFW Dresden, P.O. Box 270116, D-01171 Dresden (Germany)

2017-03-15

Composites of polymer and micron-sized particles of carbonyl-iron were investigated in terms of their magnetization behavior. Thermoplastic elastomers with varying Young's modulus (E{sub Polymer}=0.14–14.6 MPa) were used as matrix material. Field dependent magnetization curves reveal that the hysteretic behavior of the composites strongly depends on both the particle fraction (7, 10, 14, 21, 31 vol%) and on the mechanical properties of the polymer. It is shown that hysteresis only appears above a certain fraction of magnetic particles which can be accounted to the magnetic exchange between the particles. However, hysteresis is suppressed in the composite with largest Young's modulus of the polymer matrix, even at largest particle fraction. - Highlights: • Composites with soft magnetic Iron Particles show hysteretic magnetization behavior. • Origin of the hysteresis is the alignment of particles along field direction. • Hysteresis depends on both, mechanical properties of matrix and particle fraction.

On single and double soft behaviors in NLSM

International Nuclear Information System (INIS)

Du, Yi-Jian; Luo, Hui

2015-01-01

In this paper, we study the single and double soft behaviors of tree level off-shell currents and on-shell amplitudes in nonlinear sigma model (NLSM). We first propose and prove the leading soft behavior of the tree level currents with a single soft particle. In the on-shell limit, this single soft emission becomes the Adler’s zero. Then we establish the leading and subleading soft behaviors of tree level currents with two adjacent soft particles. With a careful analysis of the on-shell limit, we obtain the double soft behaviors of on-shell amplitudes where the two soft particles are adjacent to each other. By applying Kleiss-Kuijf (KK) relation, we further obtain the leading and subleading behaviors of amplitudes with two nonadjacent soft particles.

Seasonal and particle size-dependent variations in gas/particle partitioning of PCDD/Fs

International Nuclear Information System (INIS)

Lee, Se-Jin; Ale, Debaki; Chang, Yoon-Seok; Oh, Jeong-Eun; Shin, Sun Kyoung

2008-01-01

This study monitored particle size-dependent variations in atmospheric polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). Two gas/particle partitioning models, the subcooled liquid vapor pressure (P L 0 ) and the octanol-air partition coefficient (K OA ) model, were applied to each particle sizes. The regression coefficients of each fraction against the gas/particle partition coefficient (K P ) were similar for separated particles within the same sample set but differed for particles collected during different periods. Gas/particle partitioning calculated from the integral of fractions was similar to that of size-segregated particles and previously measured bulk values. Despite the different behaviors and production mechanisms of atmospheric particles of different sizes, PCDD/F partitioning of each size range was controlled by meteorological conditions such as atmospheric temperature, O 3 and UV, which reflects no source related with certain particle size ranges but mixed urban sources within this city. Our observations emphasize that when assessing environmental and health effects, the movement of PCDD/Fs in air should be considered in conjunction with particle size in addition to the bulk aerosol. - Gas/particle partitioning of atmospheric PCDD/Fs for different particle sizes reflects the impacts of emitters of different size ranges

Thermomechanical behavior of fuel particles in a matrix during reactor power excursions

International Nuclear Information System (INIS)

Brittan, R.O.; Smith, R.S.

1977-01-01

This work determines the largest particle size that can be used in fabricating fuel material without exceeding temperature or stress criteria during transient operation. To do this temperature distribution histories must be determined for various particle sizes and volume fractions using typical power densities histories of transient reactor operation. From these, the critical stresses are calculated. The model chosen to accomplish this is a spherical fuel particle in a spherical matrix shell. Heat flow and temperature continuity conditions are imposed at the interface, and a zero temperature gradient is specified at the outer radius of the matrix shell. The particle power density is assumed to be uniform radially. Provisions are made for uniform power density in the matrix to model gamma heating and power density in interface layers to allow for radiant and fission fragment heating. A computer code was prepared to solve the model performance, yielding the temperature and stress distribution histories. Material property variation with temperature is employed, along with a close mockup of the power density history during self-limiting reactor transients. To date, four fuel systems have been investigated: 1) UC.ZrC particles in graphite; 2) UO 2 particles in graphite; 3) UO 2 particles in chromium 4) UO 2 particles in stainless steel. The study indicates that the maximum allowable particle diameter varies as the square root of the initial transient period and of the particle volume fraction. The critical thermophysical parameter is the thermal diffusivity of the particle, since in all cases studied it is many times smaller than that of the matrix. That of the UC.ZrC solid solution particle is 5 or more times larger than that of the UO 2 particle. It was found that the particles of system 1) above could be about 4 times larger than that of the other sy

A better understanding of biomass co-firing by developing an advanced non-spherical particle tracking model

DEFF Research Database (Denmark)

Yin, Chungen; Rosendahl, Lasse Aistrup; Kær, Søren Knudsen

2004-01-01

-area-to-volume ratio and thus experiences a totally different motion and reaction as a non-spherical particle. Therefore, an advanced non-spherical particle-tracking model is developed to calculate the motion and reaction of nonspherical biomass particles. The biomass particles are assumed as solid or hollow cylinders......-gradient force. Since the drag and lift forces are both shape factor- and orientation-dependent, coupled particle rotation equations are resolved to update particle orientation. In the reaction of biomass particles, the actual particle surface area available and the average oxygen mass flux at particle surface...

Understanding Jordanian Psychiatric Nurses’ Smoking Behaviors: A Grounded Theory Study

Directory of Open Access Journals (Sweden)

Khaldoun M. Aldiabat

2013-01-01

Full Text Available Purpose. Smoking is prevalent in psychiatric facilities among staff and patients. However, there have been few studies of how contextual factors in specific cultures influence rates of smoking and the health promotion role of psychiatric nurses. This paper reports the findings of a classical grounded theory study conducted to understand how contextual factors in the workplace influences the smoking behaviors of Jordanian psychiatric nurses (JPNs. Method. Semi-structured individual interviews were conducted with a sample of eight male JPNs smokers at a psychiatric facility in Amman, Jordan. Findings. Constant comparative analysis identified becoming a heavy smoker as a psychosocial process characterized by four sub-categories: normalization of smoking; living in ambiguity; experiencing workplace conflict; and, facing up to workplace stressors. Conclusion. Specific contextual workplace factors require targeted smoking cessation interventions if JPNs are to receive the help they need to reduce health risks associated with heavy smoking.

SUPERPOSITION OF STOCHASTIC PROCESSES AND THE RESULTING PARTICLE DISTRIBUTIONS

International Nuclear Information System (INIS)

Schwadron, N. A.; Dayeh, M. A.; Desai, M.; Fahr, H.; Jokipii, J. R.; Lee, M. A.

2010-01-01

Many observations of suprathermal and energetic particles in the solar wind and the inner heliosheath show that distribution functions scale approximately with the inverse of particle speed (v) to the fifth power. Although there are exceptions to this behavior, there is a growing need to understand why this type of distribution function appears so frequently. This paper develops the concept that a superposition of exponential and Gaussian distributions with different characteristic speeds and temperatures show power-law tails. The particular type of distribution function, f ∝ v -5 , appears in a number of different ways: (1) a series of Poisson-like processes where entropy is maximized with the rates of individual processes inversely proportional to the characteristic exponential speed, (2) a series of Gaussian distributions where the entropy is maximized with the rates of individual processes inversely proportional to temperature and the density of individual Gaussian distributions proportional to temperature, and (3) a series of different diffusively accelerated energetic particle spectra with individual spectra derived from observations (1997-2002) of a multiplicity of different shocks. Thus, we develop a proof-of-concept for the superposition of stochastic processes that give rise to power-law distribution functions.

Influence of coal slurry particle composition on pipeline hydraulic transportation behavior

Science.gov (United States)

Li-an, Zhao; Ronghuan, Cai; Tieli, Wang

2018-02-01

Acting as a new type of energy transportation mode, the coal pipeline hydraulic transmission can reduce the energy transportation cost and the fly ash pollution of the conventional coal transportation. In this study, the effect of average velocity, particle size and pumping time on particle composition of coal particles during hydraulic conveying was investigated by ring tube test. Meanwhile, the effects of particle composition change on slurry viscosity, transmission resistance and critical sedimentation velocity were studied based on the experimental data. The experimental and theoretical analysis indicate that the alter of slurry particle composition can lead to the change of viscosity, resistance and critical velocity of slurry. Moreover, based on the previous studies, the critical velocity calculation model of coal slurry is proposed.

Understanding Organizational Advantage

DEFF Research Database (Denmark)

Stea, Diego; Linder, Stefan; Foss, Nicolai Juul

2015-01-01

The attention-based view (ABV) of the firm highlights the role of decision makers’ attention in firm behavior. The ABV vastly improves our understanding of decision makers’ focus of attention; how that focus is situated in an organization’s procedural and communication channels; and how the distr......The attention-based view (ABV) of the firm highlights the role of decision makers’ attention in firm behavior. The ABV vastly improves our understanding of decision makers’ focus of attention; how that focus is situated in an organization’s procedural and communication channels; and how...... the distribution of the focus of attention among decision makers participating in those procedural and communication channels affects their understanding of a situation, their motivation to act, and, ultimately, their behavior. Significant progress has been made in recent years in refining and extending the ABV...

AIDS, behavior, and culture: understanding evidence-based prevention

National Research Council Canada - National Science Library

Green, Edward C; Ruark, Allison Herling

2011-01-01

.... Arguing for a behavior-based approach, the authors make the case that the most effective programs are those that encourage fundamental behavioral changes such as faithfulness, avoidance of concurrent...

Formation and dynamic change of aerosol particles

International Nuclear Information System (INIS)

Kasahara, Mikio

1986-01-01

Processes of aerosol particle nucleation are roughly grouped into two types. In one, aerosol is produced as a result of dispersion of solid or liquid by mechanical force while in the other it is formed through phase transition from gas to solid or liquid due to cohesion caused by cooling, expansion or chemical reaction. This article reviews various aspects of aerosol particle nucleation through the latter type of processes and behaviors of the particles formed. Gas-to-particle conversion processes are divided into those of homogeneous and heterogeneous nucleation, and the former include homogeneous homomolecular and homogeneous heteromolecular nucleation processes. Here, homoneneous homomolecular nucleation is described centering on the theories proposed by Backer and Doring-Zeldovich-Volmer-Frenkel while homogeneous heteromolecular systems are outlined citing the theory developed by Kiang and Stauffer. Heterogeneous nucleation (or heterogeneous condensation) is discussed on the basis of the relationship between the mean free path of air molecules and the particle size. Various theories for particle formation and growth are listed and briefly outlined. Some of them are compared with experimental results. Models are cited to explain behaviors of aerosol particles after being formed. Also described is simulation of particle nucleation and growth in relation to atmospheric pollution and possible accidents of liquid-metal fast breeder reactors. (Nogami, K.)

Learning Particle Physics with DIY Play Dough Model

Science.gov (United States)

Thunyaniti, T.; Toedtanya, K.; Wuttiprom, S.

2017-09-01

The scientists once believed an atom was the smallest particle, nothing was smaller than this tiny particle. Later, they discovered an atom which consists of protons, neutrons and electrons, and they believed that these particles cannot be broken into the smaller particles. According to advanced technology, the scientists have discovered these particles are consisted of a smaller particles. The new particles are called quarks leptons and bosons which we called fundamental particle. Atomic structure cannot be observed directly, so it is complicated for studying these particles. To help the students get more understanding of its properties, so the researcher develops the learning pattern of fundamental particles from Play Dough Model for high school to graduate students. Four step of learning are 1) to introduces the concept of the fundamental particles discovery 2) to play the Happy Families game by using fundamental particles cards 3) to design and make their particle in a way that reflects its properties 4) to represents their particles from Play Dough Model. After doing activities, the students had more conceptual understanding and better memorability on fundamental particles. In addition, the students gained collaborative working experience among their friends also.

Force fields of charged particles in micro-nanofluidic preconcentration systems

Science.gov (United States)

Gong, Lingyan; Ouyang, Wei; Li, Zirui; Han, Jongyoon

2017-12-01

Electrokinetic concentration devices based on the ion concentration polarization (ICP) phenomenon have drawn much attention due to their simple setup, high enrichment factor, and easy integration with many subsequent processes, such as separation, reaction, and extraction etc. Despite significant progress in the experimental research, fundamental understanding and detailed modeling of the preconcentration systems is still lacking. The mechanism of the electrokinetic trapping of charged particles is currently limited to the force balance analysis between the electric force and fluid drag force in an over-simplified one-dimensional (1D) model, which misses many signatures of the actual system. This letter studies the particle trapping phenomena that are not explainable in the 1D model through the calculation of the two-dimensional (2D) force fields. The trapping of charged particles is shown to significantly distort the electric field and fluid flow pattern, which in turn leads to the different trapping behaviors of particles of different sizes. The mechanisms behind the protrusions and instability of the focused band, which are important factors determining overall preconcentration efficiency, are revealed through analyzing the rotating fluxes of particles in the vicinity of the ion-selective membrane. The differences in the enrichment factors of differently sized particles are understood through the interplay between the electric force and convective fluid flow. These results provide insights into the electrokinetic concentration effect, which could facilitate the design and optimization of ICP-based preconcentration systems.

Elementary particles and cosmology

International Nuclear Information System (INIS)

Audouze, J.; Paty, M.

2000-01-01

The universe is the most efficient laboratory of particle physics and the understanding of cosmological processes implies the knowledge of how elementary particles interact. This article recalls the mutual influences between on the one hand: astrophysics and cosmology and on the other hand: nuclear physics and particle physics. The big-bang theory relies on nuclear physics to explain the successive stages of nucleo-synthesis and the study of solar neutrinos has led to discover new aspects of this particle: it is likely that neutrinos undergo oscillations from one neutrino type to another. In some universe events such as the bursting of a super-nova, particles are released with a kinetic energy that would be impossible to reach on earth with a particle accelerator. These events are become common points of interest between astrophysicists and particle physicists and have promoted a deeper cooperation between astrophysics and elementary particle physics. (A.C.)

Understanding thermally activated plastic deformation behavior of Zircaloy-4

Science.gov (United States)

Kumar, N.; Alomari, A.; Murty, K. L.

2018-06-01

Understanding micromechanics of plastic deformation of existing materials is essential for improving their properties further and/or developing advanced materials for much more severe load bearing applications. The objective of the present work was to understand micromechanics of plastic deformation of Zircaloy-4, a zirconium-based alloy used as fuel cladding and channel (in BWRs) material in nuclear reactors. The Zircaloy-4 in recrystallized (at 973 K for 4 h) condition was subjected to uniaxial tensile testing at a constant cross-head velocity at temperatures in the range 293 K-1073 K and repeated stress relaxation tests at 293 K, 573 K, and 773 K. The minimum in the total elongation was indicative of dynamic strain aging phenomenon in this alloy in the intermediate temperature regime. The yield stress of the alloy was separated into effective and athermal components and the transition from thermally activated dislocation glide to athermal regime took place at around 673 K with the athermal stress estimated to be 115 MPa. The activation volume was found to be in the range of 40 b3 to 160 b3. The activation volume values and the data analyses using the solid-solution models in literature indicated dislocation-solute interaction to be a potential deformation mechanism in thermally activated regime. The activation energy calculated at 573 K was very close to that found for diffusivity of oxygen in α-Zr that was suggestive of dislocations-oxygen interaction during plastic deformation. This type of information may be helpful in alloy design in selecting different elements to control the deformation behavior of the material and impart desired mechanical properties in those materials for specific applications.

Thermomechanical behavior of tin-rich (lead-free) solders

Science.gov (United States)

Sidhu, Rajen Singh

In order to adequately characterize the behavior of ball-grid-array (BGA) Pb-free solder spheres in electronic devices, the microstructure and thermomechanical behavior need to be studied. Microstructure characterization of pure Sn, Sn-0.7Cu, Sn-3.5Ag, and Sn-3.9Ag-0.7Cu alloys was conducted using optical microscopy, scanning electron microscopy, transmission electron microscopy, image analysis, and a novel serial sectioning 3D reconstruction process. Microstructure-based finite-element method (FEM) modeling of deformation in Sn-3.5Ag alloy was conducted, and it will be shown that this technique is more accurate when compared to traditional unit cell models for simulating and understanding material behavior. The effect of cooling rate on microstructure and creep behavior of bulk Sn-rich solders was studied. The creep behavior was evaluated at 25, 95, and 120°C. Faster cooling rates were found to increase the creep strength of the solders due to refinement of the solder microstructure. The creep behavior of Sn-rich single solder spheres reflowed on Cu substrates was studied at 25, 60, 95, and 130°C. Testing was conducted using a microforce testing system, with lap-shear geometry samples. The solder joints displayed two distinct creep behaviors: (a) precipitation-strengthening (Sn-3.5Ag and Sn-3.9Ag-0.7Cu) and (b) power law creep accommodated by grain boundary sliding (GBS) (Sn and Sn-0.7Cu). The relationship between microstructural features (i.e. intermetallic particle size and spacing), stress exponents, threshold stress, and activation energies are discussed. The relationship between small-length scale creep behavior and bulk behavior is also addressed. To better understand the damage evolution in Sn-rich solder joints during thermal fatigue, the local damage will be correlated to the cyclic hysteresis behavior and crystal orientations present in the Sn phase of solder joints. FEM modeling will also be utilized to better understand the macroscopic and local

Optical trapping and binding of particles in an optofluidic stable Fabry-Pérot resonator with single-sided injection.

Science.gov (United States)

Gaber, Noha; Malak, Maurine; Marty, Frédéric; Angelescu, Dan E; Richalot, Elodie; Bourouina, Tarik

2014-07-07

In this article, microparticles are manipulated inside an optofluidic Fabry-Pérot cylindrical cavity embedding a fluidic capillary tube, taking advantage of field enhancement and multiple reflections within the optically-resonant cavity. This enables trapping of suspended particles with single-side injection of light and with low optical power. A Hermite-Gaussian standing wave is developed inside the cavity, forming trapping spots at the locations of the electromagnetic field maxima with a strong intensity gradient. The particles get arranged in a pattern related to the mechanism affecting them: either optical trapping or optical binding. This is proven to eventually translate into either an axial one dimensional (1D) particle array or a cluster of particles. Numerical simulations are performed to model the field distributions inside the cavity allowing a behavioral understanding of the phenomena involved in each case.

Electrokinetic Particle Transport in Micro-Nanofluidics Direct Numerical Simulation Analysis

CERN Document Server

Qian, Shizhi

2012-01-01

Numerous applications of micro-/nanofluidics are related to particle transport in micro-/nanoscale channels, and electrokinetics has proved to be one of the most promising tools to manipulate particles in micro/nanofluidics. Therefore, a comprehensive understanding of electrokinetic particle transport in micro-/nanoscale channels is crucial to the development of micro/nano-fluidic devices. Electrokinetic Particle Transport in Micro-/Nanofluidics: Direct Numerical Simulation Analysis provides a fundamental understanding of electrokinetic particle transport in micro-/nanofluidics involving elect

The dependence of granular plasticity on particle shape

Science.gov (United States)

Murphy, Kieran; Jaeger, Heinrich

Granular materials plastically deform through reworking an intricate network of particle-particle contacts. Some particle rearrangements have only a fleeting effect before being forgotten while others set in motion global restructuring. How particle shape affects local interactions and how those, in turn, influence the nature of the aggregate's plasticity is far from clear, especially in three dimensions. Here we investigate the remarkably wide range of behaviors in the yielding regime, from quiescent flow to violent jerks, depending on particle shape. We study this complex dependence via uniaxial compression experiments on aggregates of 3D-printed particles, and complement stress-strain data with simultaneous x-ray videos and volumetric strain measurements. We find power law distributions of the slip magnitudes, and discuss their universality. Our data show that the multitude of small slips serves to gradually dilate the packing whereas the fewer large ones accompany significant compaction events. Our findings provide new insights into general features of granular materials during plastic deformation and highlight how small changes in particle shape can give rise to drastic differences in yielding behavior.

Smoking cessation: an application of theory of planned behavior to understanding progress through stages of change.

Science.gov (United States)

Bledsoe, Linda K

2006-07-01

The purpose of this research was to investigate variables relevant to smoking cessation early in the process of change through an application of the Theory of Planned Behavior [Ajzen, I. (1985). From intentions to actions: A theory of planned behavior. In J. Kuhl and J. Beckman (Eds). Action-control: From cognition to behavior (pp.11-39). Heidelberg: Springer.] to the temporal structure provided by the Transtheoretical Model. Study 1 was a preliminary elicitation study (n=68) conducted to ground the concepts used in the model testing in Study 2 [Ajzen, I., Fishbein, M. (1980). Understanding attitudes and predicting social behavior, Englewood Cliffs, NJ: Prentice-Hall.]. Study 2 tested the proposed model fit with data from a sample of 230 adult smokers. Structural equation modeling did not support the Theory of Planned Behavior as a model of motivation for progress through the stages of change and highlighted measurement issues with perceived behavioral control. A modified model using the Theory of Reasoned Action provided a good fit to the data, accounting for approximately 64% of the variance in intention to quit smoking and stage of change. This research addresses the need for a more complete theoretical rationale for progress through stages of change.

Numerical simulation of particle-laden turbulent channel flow

NARCIS (Netherlands)

Li, Y.; McLaughlin, J.B.; Kontomaris, K.; Portela, L.

2001-01-01

This paper presents results for the behavior of particle-laden gases in a small Reynolds number vertical channel down flow. Results will be presented for the effects of particle feedback on the gas-phase turbulence and for the concentration profile of the particles. The effects of density ratio,

Rayleigh-Bénard turbulence modified by two-way coupled inertial, nonisothermal particles

Science.gov (United States)

Park, Hyungwon John; O'Keefe, Kevin; Richter, David H.

2018-03-01

Direct numerical simulation (DNS) combined with the Lagrangian point particle model is used to study Rayleigh-Bénard convection in order to understand modifications due to the interaction of inertial, nonisothermal particles with buoyancy-driven turbulence. In this system, turbulence can be altered through direct momentum coupling, as well as through buoyancy modification via thermal coupling between phases. We quantify the effect of the dispersed phase by changes to the total integrated turbulent kinetic energy (TKE) and Nusselt number (Nu). The dispersed particles experience gravitational settling and are introduced at the lower wall so that turbulence must overcome the settling velocity for the particles to vertically distribute throughout the domain. We focus primarily on particle inertia, settling velocity, mass fraction, and the ratio of the particle to fluid specific heat. Furthermore, individual contributions by the momentum coupling and thermal coupling are studied to see which most significantly changes Nu and TKE. Our results show that particles with Stokes number of order unity maximize Nu, corresponding to a peak of clustering and attenuation of TKE. Increased mass fractions lead to a linear increase of Nu and decrease of TKE. With varying specific heat ratio, Nu and TKE exhibit monotonic behaviors, where in the high limit particles become isothermal and depend upon the initialized particle temperature. It is also shown that particles two-way coupled only through momentum attenuate Nu and weaken TKE, while thermal-only coupling also weakens TKE but enhances Nu. When both couplings are present, however, thermal coupling overwhelms the momentum coupling attenuation, and the net result is an enhancement of Nu.

Fluidization of spherocylindrical particles

Science.gov (United States)

Mahajan, Vinay V.; Nijssen, Tim M. J.; Fitzgerald, Barry W.; Hofman, Jeroen; Kuipers, Hans; Padding, Johan T.

2017-06-01

Multiphase (gas-solid) flows are encountered in numerous industrial applications such as pharmaceutical, food, agricultural processing and energy generation. A coupled computational fluid dynamics (CFD) and discrete element method (DEM) approach is a popular way to study such flows at a particle scale. However, most of these studies deal with spherical particles while in reality, the particles are rarely spherical. The particle shape can have significant effect on hydrodynamics in a fluidized bed. Moreover, most studies in literature use inaccurate drag laws because accurate laws are not readily available. The drag force acting on a non-spherical particle can vary considerably with particle shape, orientation with the flow, Reynolds number and packing fraction. In this work, the CFD-DEM approach is extended to model a laboratory scale fluidized bed of spherocylinder (rod-like) particles. These rod-like particles can be classified as Geldart D particles and have an aspect ratio of 4. Experiments are performed to study the particle flow behavior in a quasi-2D fluidized bed. Numerically obtained results for pressure drop and bed height are compared with experiments. The capability of CFD-DEM approach to efficiently describe the global bed dynamics for fluidized bed of rod-like particles is demonstrated.

High-Strain-Rate Material Behavior and Adiabatic Material Instability in Impact of Micron-Scale Al-6061 Particles

Science.gov (United States)

Chen, Qiyong; Alizadeh, Arash; Xie, Wanting; Wang, Xuemei; Champagne, Victor; Gouldstone, Andrew; Lee, Jae-Hwang; Müftü, Sinan

2018-04-01

Impact of spherical particles onto a flat sapphire surface was investigated in 50-950 m/s impact speed range experimentally and theoretically. Material parameters of the bilinear Johnson-Cook model were determined based on comparison of deformed particle shapes from experiment and simulation. Effects of high-strain-rate plastic flow, heat generation due to plasticity, material damage, interfacial friction and heat transfer were modeled. Four distinct regions were identified inside the particle by analyzing temporal variation of material flow. A relatively small volume of material near the impact zone becomes unstable due to plasticity-induced heating, accompanied by severe drop in the flow stress for impact velocity that exceeds 500 m/s. Outside of this region, flow stress is reduced due to temperature effects without the instability. Load carrying capacity of the material degrades and the material expands horizontally leading to jetting. The increase in overall plastic and frictional dissipation with impact velocity was found to be inherently lower than the increase in the kinetic energy at high speeds, leading to the instability. This work introduces a novel method to characterize HSR (109 s-1) material properties and also explains coupling between HSR material behavior and mechanics that lead to extreme deformation.

Study of substrate topographical effects on epithelial cell behavior using etched alpha-particle tracks on PADC films

International Nuclear Information System (INIS)

Ng, C.K.M.; Poon, W.L.; Li, W.Y.; Cheung, T.; Cheng, S.H.; Yu, K.N.

2008-01-01

Micrometer-size pits on the surface of a polymer (polyallyldiglycol carbonate or PADC) substrate created by alpha-particle irradiation and subsequent chemical etching were used to study the topographical effects alone on cell behavior. Vinculin, the cell adhesion and membrane protrusion protein, was used as an indicator of cytoskeletonal reorganization on the substrate and localization of vinculin was used to demonstrate the presence of focal adhesions. In our experiments, vinculin expressed in epithelial HeLa cells cultured on PADC films with track-etch pits, but not in cells cultured on the raw or chemically etched blank films. In other words, vinculin expression was induced by the topography of track-etch pits, while etching of the substrate alone (without alpha-particle irradiation) did not cause up-regulation of vinculin protein expression. HeLa cells cultured on PADC films with track-etch pits also showed changes in cell proliferation, cell area and cell circularity, and were largely contained by the pits. In other words, the cell membrane edges tended to be in contact with the pits. By comparing the correlation between the positions of HeLa cells and the pits, and that between the positions of cells and computer-simulated pits, the tendency for membrane edges of HeLa cells to be in contact with the pits was recognized. This could be explained by inhibition of membrane protrusion at the pits. In conclusion, substrate track-etch pits were an important determinant of epithelial cell behaviors

Scaling during capillary thinning of particle-laden drops

Science.gov (United States)

Thete, Sumeet; Wagoner, Brayden; Basaran, Osman

2017-11-01

A fundamental understanding of drop formation is crucial in many applications such as ink-jet printing, microfluidic devices, and atomization. During drop formation, the about-to-form drop is connected to the fluid hanging from the nozzle via a thinning filament. Therefore, the physics of capillary thinning of filaments is key to understanding drop formation and has been thoroughly studied for pure Newtonian fluids using theory, simulations, and experiments. In some of the applications however, the forming drop and hence the thinning filament may contain solid particles. The thinning dynamics of such particle-laden filaments differs radically from that of particle-free filaments. Moreover, our understanding of filament thinning in the former case is poor compared to that in the latter case despite the growing interest in pinch-off of particle-laden filaments. In this work, we go beyond similar studies and experimentally explore the impact of solid particles on filament thinning by measuring both the radial and axial scalings in the neck region. The results are summarized in terms of a phase diagram of capillary thinning of particle-laden filaments.

Three-Dimensional Cell Behavior in Microgels

Science.gov (United States)

Bhattacharjee, Tapomoy; Palmer, Glyn; Ghivizzani, Steven; Keselowsky, Benjamin; Sawyer, W. Gregory; Angelini, Thomas

The number of dimensions in which particles can freely move strongly influences the collective behavior that emerges from their individual fluctuations. Thus, in 2D systems of cells in petri-dishes, our growing understanding of collective migration may be insufficient to explain cell behavior in 3D tissues. To study cell behavior in 3D, polymer scaffolds are used. Contemporary designs of 3D cell growth scaffolds enable cell migration and proliferative expansion by incorporating of degradable motifs. Matrix degradation creates space for cells to move and proliferate. However, different cell types and experimental conditions require the design of different scaffolds to optimize degradation with specific cell behaviors. By contrast, liquid like solids made from packed microgels can yield under cell generated stresses, allowing for cell motion without the need for scaffold degradation. Moreover, the use of microgels as 3D culture media allows arranging cells in arbitrary structures, harvesting cells, and delivering drugs and nutrients. Preliminary data describing cell behavior in 3D microgel culture will be presented. This material is based on work supported by the National Science Foundation under Grant No. DMR-1352043.

A demonstration of particle duality of light

Science.gov (United States)

Jiang, Haili; Liu, Zhihai; Sun, Qiuhua; Zhao, Yancheng

2017-08-01

The need of understanding and teaching about wave-particle duality if light with gets more and more apparent in the background of the attention of modern physics. As early as the beginning of twentieth Century, Einstein dared to "deny" the development of a very perfect light electromagnetic theory, so that the quantum of light can be developed. In 1924, De Broglie put forward wave-particle duality if light to other micro particles and the concept of matter wave, pointed out that all micro particle has wave-particle duality. This is a very abstract concept for students, most college physics teaching all lack of demonstration about particle duality of light. The present article aims to contribute to demonstrate the wave-particle duality of light at the same time using a simple way based on fiber optical tweezers. It is hoped that useful lesson can be absorbed so that students can deepen the understanding of the particle and wave properties of light. To complement the demonstration experiment for this attribute light has momentum.

Gallium containing composites as a tunable material to understand neuronal behavior under variable stiffness and radiation conditions

Energy Technology Data Exchange (ETDEWEB)

Berg, Nora G.; Pearce, Brady L.; Rohrbaugh, Nathaniel [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States); Jiang, Lin [Materials Science and Engineering, University of New South Wales, Sydney (Australia); Nolan, Michael W. [Department of Clinical Sciences (College of Veterinary Medicine), Comparative Medicine Institute, North Carolina State University, Raleigh, NC 27606 (United States); Ivanisevic, Albena, E-mail: ivanisevic@ncsu.edu [Department of Materials Science and Engineering, North Carolina State University, Raleigh, NC 27695 (United States)

2017-02-01

We report a composite biomaterial containing nanostructured GaOOH and Matrigel™ that can be modulated with respect to its stiffness and radiosensitization properties. A variety of concentrations of GaOOH were added to the composite to alter the mechanical properties of the material as well as to tune the radiosensitizing properties to the composite. PC-12 cells were used to study the combined effects of different stimuli on cell behavior. NGF was given to the cells to record their morphology as well as viability. An increase in the substrate stiffness caused an increase in neurite outgrowth but a decrease in cell viability. In addition, increasing the radiation dose decreased neurite outgrowth but increased cell viability when radiosensitizing particles were present. A subtractive effect between radiosensitizing and mechanical stimuli was observed when PC-12 cells were grown on the GaOOH containing composite. - Highlights: • A composite containing GaOOH and Matrigel can be used to study neurotypic cell behavior. • The composite material can be used to modulate multiple stimuli. • The neurotypic cell behavior can be altered during radiation based on the amount of GaOOH present.

Small particles big effect? - Investigating ice nucleation abilities of soot particles

Science.gov (United States)

Mahrt, Fabian; David, Robert O.; Lohmann, Ulrike; Stopford, Chris; Wu, Zhijun; Kanji, Zamin A.

2017-04-01

Atmospheric soot particles are primary particles produced by incomplete combustion of biomass and/or fossil fuels. Thus soot mainly originates from anthropogenic emissions, stemming from combustion related processes in transport vehicles, industrial and residential uses. Such soot particles are generally complex mixtures of black carbon (BC) and organic matter (OM) (Bond et al., 2013; Petzold et al., 2013), depending on the sources and the interaction of the primary particles with other atmospheric matter and/or gases BC absorbs solar radiation having a warming effect on global climate. It can also act as a heterogeneous ice nucleating particle (INP) and thus impact cloud-radiation interactions, potentially cooling the climate (Lohmann, 2002). Previous studies, however, have shown conflicting results concerning the ice nucleation ability of soot, limiting the ability to predict its effects on Earth's radiation budget. Here we present a laboratory study where we systematically investigate the ice nucleation behavior of different soot particles. Commercial soot samples are used, including an amorphous, industrial carbon frequently used in coatings and coloring (FW 200, Orion Engineered Carbons) and a fullerene soot (572497 ALDRICH), e.g. used as catalyst. In addition, we use soot generated from a propane flame Combustion Aerosol Standard Generator (miniCAST, JING AG), as a proxy for atmospheric soot particles. The ice nucleation ability of these soot types is tested on size-selected particles for a wide temperature range from 253 K to 218 K, using the Horizontal Ice Nucleation Chamber (HINC), a Continuous Flow Diffusion Chamber (CFDC) (Kanji and Abbatt, 2009). Ice nucleation results from these soot surrogates will be compared to chemically more complex real world samples, collected on filters. Filters will be collected during the 2016/2017 winter haze periods in Beijing, China and represent atmospheric soot particles with sources from both industrial and residential

Understanding of impurity behavior in SST-1 plasmas using visible spectroscopy

International Nuclear Information System (INIS)

Manchanda, Ranjana; Ramaiya, Nilam; Chowdhuri, Malay Bikas; Banerjee, Santanu; Ghosh, Joydeep

2015-01-01

Studies of impurity behavior in SST-1 plasma have been carried out using visible spectroscopic systems installed on the tokomak. This has been carried out using a low resolution and broadband survey spectrometer covering a 350-900 nm wavelength range, 0.5 m visible spectrometer having 600 and 1200 grooves/mm grating coupled with CCD camera and interference filter and photomultiplier (PMT) tube based systems. Temporal evolution of the hydrogen (H α , H β ) and impurities emissions like, C II, C III, O I, O II, O III, O V and a visible Continuum at 536.0 nm have been monitored using the PMT based system to understand impurity charge state evolution during plasma discharges. All systems are absolutely calibrated for impurity influx and plasma parameter estimations. Observed spectral lines in the visible range have been identified to recognize the presence of various impurities in the SST-1 plasmas. Comparison of impurities emission has been made for different plasma currents and toroidal magnetic fields. An analysis has been carried out to understand the impurities activities in plasmas of SST-1 tokomak in presence and absence of installed plasma facing components (PFC). Significantly higher carbon emissions have been observed indicating higher carbon content in the plasma with graphite PFCs installed. (author)

Particle physics

International Nuclear Information System (INIS)

Kamal, Anwar

2014-01-01

Provides step-by-step derivations. Contains numerous tables and diagrams. Supports learning and teaching with numerous worked examples, questions and problems with answers. Sketches also the historical development of the subject. This textbook teaches particle physics very didactically. It supports learning and teaching with numerous worked examples, questions and problems with answers. Numerous tables and diagrams lead to a better understanding of the explanations. The content of the book covers all important topics of particle physics: Elementary particles are classified from the point of view of the four fundamental interactions. The nomenclature used in particle physics is explained. The discoveries and properties of known elementary particles and resonances are given. The particles considered are positrons, muon, pions, anti-protons, strange particles, neutrino and hadrons. The conservation laws governing the interactions of elementary particles are given. The concepts of parity, spin, charge conjugation, time reversal and gauge invariance are explained. The quark theory is introduced to explain the hadron structure and strong interactions. The solar neutrino problem is considered. Weak interactions are classified into various types, and the selection rules are stated. Non-conservation of parity and the universality of the weak interactions are discussed. Neutral and charged currents, discovery of W and Z bosons and the early universe form important topics of the electroweak interactions. The principles of high energy accelerators including colliders are elaborately explained. Additionally, in the book detectors used in nuclear and particle physics are described. This book is on the upper undergraduate level.

Bridging the Gap: Towards a Cell-Type Specific Understanding of Neural Circuits Underlying Fear Behaviors

Science.gov (United States)

McCullough, KM; Morrison, FG; Ressler, KJ

2016-01-01

Fear and anxiety-related disorders are remarkably common and debilitating, and are often characterized by dysregulated fear responses. Rodent models of fear learning and memory have taken great strides towards elucidating the specific neuronal circuitries underlying the learning of fear responses. The present review addresses recent research utilizing optogenetic approaches to parse circuitries underlying fear behaviors. It also highlights the powerful advances made when optogenetic techniques are utilized in a genetically defined, cell-type specific, manner. The application of next-generation genetic and sequencing approaches in a cell-type specific context will be essential for a mechanistic understanding of the neural circuitry underlying fear behavior and for the rational design of targeted, circuit specific, pharmacologic interventions for the treatment and prevention of fear-related disorders. PMID:27470092

Novel Discrete Element Method for 3D non-spherical granular particles.

Science.gov (United States)

Seelen, Luuk; Padding, Johan; Kuipers, Hans

2015-11-01

Granular materials are common in many industries and nature. The different properties from solid behavior to fluid like behavior are well known but less well understood. The main aim of our work is to develop a discrete element method (DEM) to simulate non-spherical granular particles. The non-spherical shape of particles is important, as it controls the behavior of the granular materials in many situations, such as static systems of packed particles. In such systems the packing fraction is determined by the particle shape. We developed a novel 3D discrete element method that simulates the particle-particle interactions for a wide variety of shapes. The model can simulate quadratic shapes such as spheres, ellipsoids, cylinders. More importantly, any convex polyhedron can be used as a granular particle shape. These polyhedrons are very well suited to represent non-rounded sand particles. The main difficulty of any non-spherical DEM is the determination of particle-particle overlap. Our model uses two iterative geometric algorithms to determine the overlap. The algorithms are robust and can also determine multiple contact points which can occur for these shapes. With this method we are able to study different applications such as the discharging of a hopper or silo. Another application the creation of a random close packing, to determine the solid volume fraction as a function of the particle shape.

Structures in elementary particles. An electromagnetic elementary-particle model

International Nuclear Information System (INIS)

Meyer, Carl-Friedrich

2015-01-01

A picture of matter is developed, which is suited to develope and to explain the experimentally determined properties of the elementary particles and the basing structures starting from few known physical conditions in a simple and understandable way. It explains illustratively the spin and the structure of the stable particles, symmetry properties resulting from the half-integerness of the spin, the nature of the electric charge and the third-integerness of the charges in hadrons resulting from this, the stability and the indivisibility f the proton, the conditions for the formation and stability of the particles, and the causes for the limited lifetime of unstable particles like the free neutron. It opens also the view on the cause for the quantization of all for us known processes in the range of the microcosm and creates so an illustrative picture of the matter surrounding us.

Fast inertial particle manipulation in oscillating flows

Science.gov (United States)

Thameem, Raqeeb; Rallabandi, Bhargav; Hilgenfeldt, Sascha

2017-05-01

It is demonstrated that micron-sized particles suspended in fluid near oscillating interfaces experience strong inertial displacements above and beyond the fluid streaming. Experiments with oscillating bubbles show rectified particle lift over extraordinarily short (millisecond) times. A quantitative model on both the oscillatory and the steady time scales describes the particle displacement relative to the fluid motion. The formalism yields analytical predictions confirming the observed scaling behavior with particle size and experimental control parameters. It applies to a large class of oscillatory flows with applications from particle trapping to size sorting.

Puzzle of the particles and the universe. The inner life of the elementary particles IX d

International Nuclear Information System (INIS)

Geitner, Uwe W.

2013-01-01

The series The Inner Life of the Elementary Particles attempts to develop the elementary particles along of a genealogical tree, which begins before the ''big bang''. The simple presentation without mathematics opens also for the interested layman a plastic understanding. Volume IX discusses the known puzzles of particle physics and cosmology and offers for many of them explanation models. Explanation approaches are among others the ''DNA'' of the elementary particles and the interpretation of the quanta and the spin.

Vertical pneumatic conveying in dilute and dense-phase flows: experimental study of the influence of particle density and diameter on fluid dynamic behavior

Directory of Open Access Journals (Sweden)

Narimatsu C.P.

2001-01-01

Full Text Available In this work, the effects of particle size and density on the fluid dynamic behavior of vertical gas-solid transport of Group D particles in a 53.4 mm diameter transport tube were studied. For the conditions tested, the experimental curves of pressure gradient versus air velocity presented a minimum pressure gradient point, which is associated with a change in the flow regime from dense to dilute phase. The increases in particle size from 1.00 to 3.68 mm and in density from 935 to 2500 kg/m³ caused an increase in pressure gradient for the dense-phase transport region, but were not relevant in dilute transport. The transition velocity between dense and dilute flow (Umin also increased with increasing particle density and diameter. An empirical equation was fitted for predicting transition air velocity for the transport of glass spheres. Additional experiments, covering a wider range of conditions and particles properties, are still needed to allow the fitting of a generalized equation for prediction of Umin.

Survey report on awareness and participation behavior in disabled sports and disability understanding after Tokyo's bid for the 2020 Olympics and Paralympics.

Science.gov (United States)

Shiota, Kotomi

2018-01-01

[Purpose] This study analyzes awareness and participation behavior in disabled sports and disability understanding after Tokyo's bid for the 2020 Olympics and Paralympics. [Subjects and Methods] The study conducted a cross survey on 220 registrants of an Internet research firm. It analyzed: the awareness of citizens and their behavioral changes, in the aftermath of the allocation of Olympic and Paralympic Games; subject attributes and education level; recognition of disabled sports; and the awareness and behavior of participants, with regard to disabled sports. The analysis was conducted using SPSS Ver. 21 (IBM). [Results] The subjects were not interested in watching (72.2%), participating (76.8%), or volunteering (71.8%) in disabled sports. In addition, 76.8% of the subjects exhibited no behavioral changes-such as by watching, participating, or volunteering in disabled sports-after the Olympics and Paralympics bid decision. [Conclusion] This study's subjects had no confidence in their disability knowledge and no opportunities to interact with disabled persons. Furthermore, the bids for mega-events such as the Olympic and Paralympic Games did not lead to behavioral changes concerning disabled sports. Therefore, disability understanding should promote and deepen participation behavior in disabled sports.

Promoting smoke-free homes: a novel behavioral intervention using real-time audio-visual feedback on airborne particle levels.

Directory of Open Access Journals (Sweden)

Neil E Klepeis

Full Text Available Interventions are needed to protect the health of children who live with smokers. We pilot-tested a real-time intervention for promoting behavior change in homes that reduces second hand tobacco smoke (SHS levels. The intervention uses a monitor and feedback system to provide immediate auditory and visual signals triggered at defined thresholds of fine particle concentration. Dynamic graphs of real-time particle levels are also shown on a computer screen. We experimentally evaluated the system, field-tested it in homes with smokers, and conducted focus groups to obtain general opinions. Laboratory tests of the monitor demonstrated SHS sensitivity, stability, precision equivalent to at least 1 µg/m(3, and low noise. A linear relationship (R(2 = 0.98 was observed between the monitor and average SHS mass concentrations up to 150 µg/m(3. Focus groups and interviews with intervention participants showed in-home use to be acceptable and feasible. The intervention was evaluated in 3 homes with combined baseline and intervention periods lasting 9 to 15 full days. Two families modified their behavior by opening windows or doors, smoking outdoors, or smoking less. We observed evidence of lower SHS levels in these homes. The remaining household voiced reluctance to changing their smoking activity and did not exhibit lower SHS levels in main smoking areas or clear behavior change; however, family members expressed receptivity to smoking outdoors. This study established the feasibility of the real-time intervention, laying the groundwork for controlled trials with larger sample sizes. Visual and auditory cues may prompt family members to take immediate action to reduce SHS levels. Dynamic graphs of SHS levels may help families make decisions about specific mitigation approaches.

Four different animated sub-particles as the origins of the life and creator of different angular momentums of elementary particles

Science.gov (United States)

Gholibeigian, Hassan; Gholibeigian, Zeinab

2015-04-01

Understanding the internal structure of the proton is crucial challenge for QCD, and one important aspect of this is to understand how the spin of the nucleon is build-up from the angular momentum of its quarks and gluons. In this way, what's the origin of differences between angular momentums of fundamental particles? It may be from their substructures. It seems there are four sub-particles of mater, plant, animal and human in substructure of each fundamental particle (string) as the origins of life and cause of differences between spins of those elementary particles. Material's sub-particle always is on and active. When the environmental conditions became ready for creation of each field of the plant, animal and human, sub-particles of their elementary particles became on and active and then, those elementary particles participated in processes of creation in their own field. God, as the main source of information, has been communicated with their sub-particles and transfers a package (bit) of information and laws (plus standard ethics for human sub-particles) to each of them for process and selection (mutation) of the next step of motion and interaction of their fundamental particles with each other in each Plank's time. This is causality for particles' motion in quantum area.

Experimental and computational investigation of the dynamic behavior of Al–Cu–Li alloys

Energy Technology Data Exchange (ETDEWEB)

Khanikar, Prasenjit [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 (United States); Liu, Yi [Analytical Instrumentation Facility, North Carolina State University, Raleigh, NC 27695-7531 (United States); Zikry, M.A., E-mail: zikry@ncsu.edu [Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, NC 27695-7910 (United States)

2014-05-01

A dislocation-density based crystalline plasticity formulation, finite-element techniques, rational crystallographic orientation relations and a new fracture methodology were used to predict the failure modes associated with the high strain rate behavior of high strength Al–Cu–Li alloys. Widely used aluminum alloy 2195 (AA2195) was taken as the representative of Al–Cu–Li alloys. Experimental characterization using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were performed to gain insights on microstructural behavior. The alloy aggregate was modeled with representative microstructures that included precipitates, dispersed particles, and different grain boundary (GB) distributions. The new fracture methodology, based on overlapping elements and phantom nodes, was used with a fracture criteria specialized for fracture on different cleavage planes to investigate dynamic crack nucleation and growth. The compressive behavior of AA2195 under high strain rate loading was compared with that of Al–Cu alloy 2139 to further understand the behavior of the AA2195 with the more ductile AA2139. The predictions quantify how local microstructural effects, due to precipitates and dispersed particles, have a dominant effect on crack initiation and growth.

Understanding Youth's Health-Compromising Behaviors in Germany: An Application of the Risk-Behavior Framework.

Science.gov (United States)

Hazard, Barbara P.; Lee, Che-Fu

1999-01-01

Analyzed the health-compromising behaviors of German youth using responses of 2,330 seventh, eighth, and ninth graders from the German Youth Study. Smoking and drinking are not seen by these students as health-threatening behaviors, but as socially appealing behaviors. Discusses implications for health education. (SLD)

Understanding User Behavioral Patterns in Open Knowledge Communities

Science.gov (United States)

Yang, Xianmin; Song, Shuqiang; Zhao, Xinshuo; Yu, Shengquan

2018-01-01

Open knowledge communities (OKCs) have become popular in the era of knowledge economy. This study aimed to explore how users collaboratively create and share knowledge in OKCs. In particular, this research identified the behavior distribution and behavioral patterns of users by conducting frequency distribution and lag sequential analyses. Some…

Hamiltonian action of spinning particle with gravimagnetic moment

International Nuclear Information System (INIS)

Deriglazov, Alexei A; Ramírez, W Guzmán

2016-01-01

We develop Hamiltonian variational problem for spinning particle non-minimally interacting with gravity through the gravimagnetic moment κ. For κ = 0 our model yields Mathisson-Papapetrou-Tulczyjew-Dixon (MPTD) equations, the latter show unsatisfactory behavior of MPTD-particle in ultra-relativistic regime: its longitudinal acceleration increases with velocity. κ = 1 yields a modification of MPTD-equations with the reasonable behavior: in the homogeneous fields, both longitudinal acceleration and (covariant) precession of spin-tensor vanish as v→c. (paper)

Understanding the creation of & reducing surface microroughness during polishing & post-processing of glass optics

Energy Technology Data Exchange (ETDEWEB)

Suratwala, Tayyab [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-09-22

In the follow study, we have developed a detailed understanding of the chemical and mechanical microscopic interactions that occur during polishing affecting the resulting surface microroughness of the workpiece. Through targeted experiments and modeling, the quantitative relationships of many important polishing parameters & characteristics affecting surface microroughness have been determined. These behaviors and phenomena have been described by a number of models including: (a) the Ensemble Hertzian Multi Gap (EHMG) model used to predict the removal rate and roughness at atomic force microscope (AFM) scale lengths as a function of various polishing parameters, (b) the Island Distribution Gap (IDG) model used to predict the roughness at larger scale lengths, (c) the Deraguin-Verwey-Landau-Overbeek (DLVO) 3-body electrostatic colloidal model used to predict the interaction of slurry particles at the interface and roughness behavior as a function of pH, and (d) a diffusion/chemical reaction rate model of the incorporation of impurities species into the polishing surface layer (called the Bielby layer). Based on this improved understanding, novel strategies to polish the workpiece have been developed simultaneously leading to both ultrasmooth surfaces and high material removal rates. Some of these strategies include: (a) use of narrow PSD slurries, (b) a novel diamond conditioning recipe of the lap to increase the active contact area between the workpiece and lap without destroying its surface figure, (c) proper control of pH for a given glass type to allow for a uniform distribution of slurry particles at the interface, and (d) increase in applied load just up to the transition between molecular to plastic removal regime for a single slurry particle. These techniques have been incorporated into a previously developed finishing process called Convergent Polishing leading to not just economical finishing process with improved surface figure control, but also

Applied Behavior Analysis, Autism, and Occupational Therapy: A Search for Understanding.

Science.gov (United States)

Welch, Christie D; Polatajko, H J

2016-01-01

Occupational therapists strive to be mindful, competent practitioners and continuously look for ways to improve practice. Applied behavior analysis (ABA) has strong evidence of effectiveness in helping people with autism achieve goals, yet it does not seem to be implemented in occupational therapy practice. To better understand whether ABA could be an evidence-based option to expand occupational therapy practice, the authors conducted an iterative, multiphase investigation of relevant literature. Findings suggest that occupational therapists apply developmental and sensory approaches to autism treatment. The occupational therapy literature does not reflect any use of ABA despite its strong evidence base. Occupational therapists may currently avoid using ABA principles because of a perception that ABA is not client centered. ABA principles and occupational therapy are compatible, and the two could work synergistically. Copyright © 2016 by the American Occupational Therapy Association, Inc.

Higgs Particle: The Origin of Mass

Science.gov (United States)

Okada, Yasuhiro

2007-11-01

The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments, LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generation mechanism, which could lead to a deeper understanding of particle physics.

Higgs particle. The origin of mass

International Nuclear Information System (INIS)

Okada, Yasuhiro

2007-01-01

The Higgs particle is a new elementary particle predicted in the Standard Model of the elementary particle physics. It plays a special role in the theory of mass generation of quarks, leptons, and gauge bosons. In this article, theoretical issues on the Higgs mechanism are first discussed, and then experimental prospects on the Higgs particle study at the future collider experiments. LHC and ILC, are reviewed. The Higgs coupling determination is an essential step to establish the mass generation mechanism, which could lead to a deeper understanding of particle physics. (author)

Dynamics of colloidal particles in ice

KAUST Repository

Spannuth, Melissa

2011-01-01

We use x-ray photon correlation spectroscopy (XPCS) to probe the dynamics of colloidal particles in polycrystalline ice. During freezing, the dendritic ice morphology and rejection of particles from the ice created regions of high particle density, where some of the colloids were forced into contact and formed disordered aggregates. The particles in these high density regions underwent ballistic motion, with a characteristic velocity that increased with temperature. This ballistic motion is coupled with both stretched and compressed exponential decays of the intensity autocorrelation function. We suggest that this behavior could result from ice grain boundary migration. © 2011 American Institute of Physics.

Development and applications of single particle orientation and rotational tracking in dynamic systems

Energy Technology Data Exchange (ETDEWEB)

Chen, Kuangcai [Iowa State Univ., Ames, IA (United States)

2016-02-19

The goal of this study is to help with future data analysis and experiment designs in rotational dynamics research using DIC-based SPORT technique. Most of the current studies using DIC-based SPORT techniques are technical demonstrations. Understanding the mechanisms behind the observed rotational behaviors of the imaging probes should be the focus of the future SPORT studies. More efforts are still needed in the development of new imaging probes, particle tracking methods, instrumentations, and advanced data analysis methods to further extend the potential of DIC-based SPORT technique.

Toward a quantitative understanding of mechanical behavior of nanocrystalline metals

International Nuclear Information System (INIS)

Dao, M.; Lu, L.; Asaro, R.J.; Hosson, J.T.M. de; Ma, E.

2007-01-01

Focusing on nanocrystalline (nc) pure face-centered cubic metals, where systematic experimental data are available, this paper presents a brief overview of the recent progress made in improving mechanical properties of nc materials, and in quantitatively and mechanistically understanding the underlying mechanisms. The mechanical properties reviewed include strength, ductility, strain rate and temperature dependence, fatigue and tribological properties. The highlighted examples include recent experimental studies in obtaining both high strength and considerable ductility, the compromise between enhanced fatigue limit and reduced crack growth resistance, the stress-assisted dynamic grain growth during deformation, and the relation between rate sensitivity and possible deformation mechanisms. The recent advances in obtaining quantitative and mechanics-based models, developed in line with the related transmission electron microscopy and relevant molecular dynamics observations, are discussed with particular attention to mechanistic models of partial/perfect-dislocation or deformation-twin-mediated deformation processes interacting with grain boundaries, constitutive modeling and simulations of grain size distribution and dynamic grain growth, and physically motivated crystal plasticity modeling of pure Cu with nanoscale growth twins. Sustained research efforts have established a group of nanocrystalline and nanostructured metals that exhibit a combination of high strength and considerable ductility in tension. Accompanying the gradually deepening understanding of the deformation mechanisms and their relative importance, quantitative and mechanisms-based constitutive models that can realistically capture experimentally measured and grain-size-dependent stress-strain behavior, strain-rate sensitivity and even ductility limit are becoming available. Some outstanding issues and future opportunities are listed and discussed

Particle and surfactant interactions effected polar and dispersive components of interfacial energy in nanocolloids

Science.gov (United States)

Harikrishnan, A. R.; Das, Sarit K.; Agnihotri, Prabhat K.; Dhar, Purbarun

2017-08-01

We segregate and report experimentally for the first time the polar and dispersive interfacial energy components of complex nanocolloidal dispersions. In the present study, we introduce a novel inverse protocol for the classical Owens Wendt method to determine the constitutive polar and dispersive elements of surface tension in such multicomponent fluidic systems. The effect of nanoparticles alone and aqueous surfactants alone are studied independently to understand the role of the concentration of the dispersed phase in modulating the constitutive elements of surface energy in fluids. Surfactants are capable of altering the polar component, and the combined particle and surfactant nanodispersions are shown to be effective in modulating the polar and dispersive components of surface tension depending on the relative particle and surfactant concentrations as well as the morphological and electrostatic nature of the dispersed phases. We observe that the combined surfactant and particle colloid exhibits a similar behavior to that of the particle only case; however, the amount of modulation of the polar and dispersive constituents is found to be different from the particle alone case which brings to the forefront the mechanisms through which surfactants modulate interfacial energies in complex fluids. Accordingly, we are able to show that the observations can be merged into a form of quasi-universal trend in the trends of polar and dispersive components in spite of the non-universal character in the wetting behavior of the fluids. We analyze the different factors affecting the polar and dispersive interactions in such complex colloids, and the physics behind such complex interactions has been explained by appealing to the classical dispersion theories by London, Debye, and Keesom as well as by Derjaguin-Landau-Verwey-Overbeek theory. The findings shed light on the nature of wetting behavior of such complex fluids and help in predicting the wettability and the degree of

Entanglement of identical particles and the detection process

DEFF Research Database (Denmark)

Tichy, Malte C.; de Melo, Fernando; Kus, Marek

2013-01-01

We introduce detector-level entanglement, a unified entanglement concept for identical particles that takes into account the possible deletion of many-particle which-way information through the detection process. The concept implies a measure for the effective indistinguishability of the particles...... statistical behavior depends on their initial entanglement. Our results show that entanglement cannot be attributed to a state of identical particles alone, but that the detection process has to be incorporated in the analysis....

Pattern formation in annular systems of repulsive particles

International Nuclear Information System (INIS)

Marschler, Christian; Starke, Jens; Sørensen, Mads P.; Gaididei, Yuri B.; Christiansen, Peter L.

2016-01-01

General particle models with symmetric and asymmetric repulsion are studied and investigated for finite-range and exponential interaction in an annulus. In the symmetric case transitions from one- to multi-lane behavior including multistability are observed for varying particle density and for a varying curvature with fixed density. Hence, the system cannot be approximated by a periodic channel. In the asymmetric case, which is important in pedestrian dynamics, we reveal an inhomogeneous new phase, a traveling wave reminiscent of peristaltic motion. - Highlights: • An asymmetrically interacting repulsive particle model is introduced. • Multi-stability is found in a pedestrian dynamics model. • Transitions from one- to multi-lane behavior are studied numerically.

Understanding persuasion contexts in health gamification: A systematic analysis of gamified health behavior change support systems literature.

Science.gov (United States)

Alahäivälä, Tuomas; Oinas-Kukkonen, Harri

2016-12-01

Gamification is increasingly used as a design strategy when developing behavior change support systems in the healthcare domain. It is commonly agreed that understanding the contextual factors is critical for successful gamification, but systematic analyses of the persuasive contexts have been lacking so far within gamified health intervention studies. Through a persuasion context analysis of the gamified health behavior change support systems (hBCSSs) literature, we inspect how the contextual factors have been addressed in the prior gamified health BCSS studies. The implications of this study are to provide the practitioners and researchers examples of how to conduct a systematic analysis to help guide the design and research on gamified health BCSSs. The ideas derived from the analysis of the included studies will help identify potential pitfalls and shortcomings in both the research and implementations of gamified health behavior change support systems. We systematically analyzed the persuasion contexts of 15 gamified health intervention studies. According to our results, gamified hBCSSs are implemented under different facets of lifestyle change and treatments compliance, and use a multitude of technologies and methods. We present a set of ideas and concepts to help improve endeavors in studying gamified health intervention through comprehensive understanding of the persuasive contextual factors. Future research on gamified hBCSSs should systematically compare the different combinations of contextual factors, related theories, chosen gamification strategies, and the study of outcomes to help understand how to achieve the most efficient use of gamification on the different aspects of healthcare. Analyzing the persuasion context is essential to achieve this. With the attained knowledge, those planning health interventions can choose the 'tried-and-tested' approaches for each particular situation, rather than develop solutions in an ad-hoc manner. Copyright © 2016

25th Anniversary Article: Polymer-Particle Composites: Phase Stability and Applications in Electrochemical Energy Storage

KAUST Repository

Srivastava, Samanvaya

2013-12-09

Polymer-particle composites are used in virtually every field of technology. When the particles approach nanometer dimensions, large interfacial regions are created. In favorable situations, the spatial distribution of these interfaces can be controlled to create new hybrid materials with physical and transport properties inaccessible in their constituents or poorly prepared mixtures. This review surveys progress in the last decade in understanding phase behavior, structure, and properties of nanoparticle-polymer composites. The review takes a decidedly polymers perspective and explores how physical and chemical approaches may be employed to create hybrids with controlled distribution of particles. Applications are studied in two contexts of contemporary interest: battery electrolytes and electrodes. In the former, the role of dispersed and aggregated particles on ion-transport is considered. In the latter, the polymer is employed in such small quantities that it has been historically given titles such as binder and carbon precursor that underscore its perceived secondary role. Considering the myriad functions the binder plays in an electrode, it is surprising that highly filled composites have not received more attention. Opportunities in this and related areas are highlighted where recent advances in synthesis and polymer science are inspiring new approaches, and where newcomers to the field could make important contributions. Polymer-particle composites are used in virtually every field of technology. When the particles approach nanometer dimensions, large interfacial regions are created that can be exploited for applications. The fundamental approaches and bottom-up synthesis strategies for understanding and controlling nanoparticle dispersion in polymers are reviewed. Applications of these approaches for creating polymer-particle composite electrolytes and electrodes for energy storage are also considered. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Validation of new empirical model for self-leveling behavior of cylindrical particle beds based on experimental database

International Nuclear Information System (INIS)

Morita, Koji; Matsumoto, Tatsuya; Taketa, Shohei; Nishi, Shinpei; Cheng, Songbai; Suzuki, Tohru; Tobita, Yoshiharu

2014-01-01

During a material relocation phase of core disruptive accidents (CDAs) in sodium cooled fast reactors (SFRs), debris beds can be formed in the lower plenum region due to rapid quenching and fragmentation of molten core materials. Heat removal from debris beds is crucial to achieve so called in-vessel retention (IVR) of degraded core materials. Coolant boiling in the beds may lead to leveling of their mound shape, and then changes coolability of the beds with decay heat as well as neutronic characteristics. To clarify the mechanisms underlying this self-leveling behavior, several series of experiments using simulant materials has been performed in collaboration between Japan Atomic Energy Agency (JAEA) and Kyushu University in Japan. In the present study, experiments in a cylindrical system were employed to develop experimental data on self-leveling process of particle beds. In the experiments, to simulate the coolant boiling due to the decay heat in fuel, nitrogen gas was percolated uniformly through the bottom of the particle bed with a conical shape mound using a gas injection method. Time variations in bed height during the self-leveling process were measured for key experimental parameters on particle size, density and sphericity, and gas flow rate. Using a dimensional analysis approach, a new model was proposed to correlate the experimental data on transient bed height with an empirical equation using a characteristic time of self-leveling development and a terminal equilibrium height of the bed. It was demonstrated that the proposed model predicts self-leveling development of particle beds with reasonable accuracy in the present ranges of experimental conditions. (author)

Ratchet Transport of Chiral Particles Caused by the Transversal Asymmetry: Current Reversals and Particle Separation

Science.gov (United States)

Liu, Jian-li; Lu, Shi-cai; Ai, Bao-quan

2018-06-01

Due to the chirality of active particles, the transversal asymmetry can induce the the longitudinal directed transport. The transport of chiral active particles in a periodic channel is investigated in the presence of two types of the transversal asymmetry, the transverse force and the transverse rigid half-circle obstacles. For all cases, the counterclockwise and clockwise particles move to the opposite directions. For the case of the only transverse force, the chiral active particles can reverse their directions when increasing the transverse force. When the transverse rigid half-circle obstacles are introduced, the transport behavior of particles becomes more complex and multiple current reversals occur. The direction of the transport is determined by the competition between two types of the transversal asymmetry. For a given chirality, by suitably tailoring parameters, particles with different self-propulsion speed can move in different directions and can be separated.

Numerical study of shear thickening fluid with discrete particles embedded in a base fluid

Directory of Open Access Journals (Sweden)

W Zhu

2016-09-01

Full Text Available The Shear Thickening Fluid (STF is a dilatant material, which displays non-Newtonian characteristics in its unique ability to transit from a low viscosity fluid to a high viscosity fluid. The research performed investigates the STF behavior by modeling and simulation of the interaction between the base flow and embedded rigid particles when subjected to shear stress. The model considered the Lagrangian description of the rigid particles and the Eulerian description of fluid flow. The numerical analysis investigated key parameters such as applied flow acceleration, particle distribution and arrangement, volume concentration of particles, particle size, shape and their behavior in a Newtonian and non-Newtonian fluid base. The fluid-particle interaction model showed that the arrangement, size, shape and volume concentration of the particles had a significant effect on the behavior of the STF. Although non-conclusive, the addition of particles in non-Newtonian fluids showed a promising trend of improved shear thickening effects at high shear strain rates.

Fractals control in particle's velocity

International Nuclear Information System (INIS)

Zhang Yongping; Liu Shutang; Shen Shulan

2009-01-01

Julia set, a fractal set of the literature of nonlinear physics, has significance for the engineering applications. For example, the fractal structure characteristics of the generalized M-J set could visually reflect the change rule of particle's velocity. According to the real world requirement, the system need show various particle's velocity in some cases. Thus, the control of the nonlinear behavior, i.e., Julia set, has attracted broad attention. In this work, an auxiliary feedback control is introduced to effectively control the Julia set that visually reflects the change rule of particle's velocity. It satisfies the performance requirement of the real world problems.

Particle size- and concentration-dependent separation of magnetic nanoparticles

Energy Technology Data Exchange (ETDEWEB)

Witte, Kerstin, E-mail: witte@micromod.de [University of Rostock, Institute of Physics, Albert-Einstein-Str. 23, 18059 Rostock (Germany); Micromod Partikeltechnologie GmbH, Friedrich-Barnewitz-Str. 4, 18119 Rostock (Germany); Müller, Knut; Grüttner, Cordula; Westphal, Fritz [Micromod Partikeltechnologie GmbH, Friedrich-Barnewitz-Str. 4, 18119 Rostock (Germany); Johansson, Christer [Acreo Swedish ICT AB, 40014 Göteborg (Sweden)

2017-04-01

Small magnetic nanoparticles with a narrow size distribution are of great interest for several biomedical applications. When the size of the particles decreases, the magnetic moment of the particles decreases. This leads to a significant increase in the separation time by several orders of magnitude. Therefore, in the present study the separation processes of bionized nanoferrites (BNF) with different sizes and concentrations were investigated with the commercial Sepmag Q system. It was found that an increasing initial particle concentration leads to a reduction of the separation time for large nanoparticles due to the higher probability of building chains. Small nanoparticles showed exactly the opposite behavior with rising particle concentration up to 0.1 mg(Fe)/ml. For higher iron concentrations the separation time remains constant and the measured Z-average decreases in the supernatant at same time intervals. At half separation time a high yield with decreasing hydrodynamic diameter of particles can be obtained using higher initial particle concentrations. - Highlights: • Size dependent separation processes of multicore nanoparticles. • Concentration dependent separation processes of multicore nanoparticles. • Increasing separation time with rising concentrations for small particles. • Large particles show typical cooperative magnetophoresis behavior.

Simulation of concentration distribution of urban particles under wind

Science.gov (United States)

Chen, Yanghou; Yang, Hangsheng

2018-02-01

The concentration of particulate matter in the air is too high, which seriously affects people’s health. The concentration of particles in densely populated towns is also high. Understanding the distribution of particles in the air helps to remove them passively. The concentration distribution of particles in urban streets is simulated by using the FLUENT software. The simulation analysis based on Discrete Phase Modelling (DPM) of FLUENT. Simulation results show that the distribution of the particles is caused by different layout of buildings. And it is pointed out that in the windward area of the building and the leeward sides of the high-rise building are the areas with high concentration of particles. Understanding the concentration of particles in different areas is also helpful for people to avoid and reduce the concentration of particles in high concentration areas.

The Particle Theory of Matter

Science.gov (United States)

Widick, Paul R.

1969-01-01

Described are activities that are designed to help elementary children understand the possibility of the particle theory of matter. Children work with beads, marbles, B-B shot and sand; by mixing these materials and others they are led to see that it is highly possible for the existence of particles which are not visible. (BR)

Localization in small fcc-particles with surface irregularities and disorder

International Nuclear Information System (INIS)

Bucher, J.P.; Bloomfield, L.A.

1991-01-01

A numerical eigenvector analysis is used to investigate Anderson localization in small fcc-particles of N = 309 and N = 147 atoms. Special attention is given to the way size and surface roughness of the particles influence the localization behavior. States begin to localize in a non-exponential regime several lattice spacings from the center of localization and finally converge to a fully exponentially-localized regime for strong disorder. For smooth surface particles, it is found that the states localize first at the band bottom and a mobility edge can clearly be defined for increasing disorder. This doesn't seem to be the case for the rougher particles, where the band middle and the band bottom show similar behavior towards localization. Although particles with surface irregularities show an onset of localization for smaller values of the disorder than smooth particles, the localization length is greater. (orig.)

Diffusion of oriented particles in porous media

Energy Technology Data Exchange (ETDEWEB)

Haber, René [Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Centre for Nonlinear Studies, Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Prehl, Janett [Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz (Germany); Herrmann, Heiko [Centre for Nonlinear Studies, Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn (Estonia); Hoffmann, Karl Heinz, E-mail: hoffmann@physik.tu-chemnitz.de [Institut für Physik, Technische Universität Chemnitz, D-09107 Chemnitz (Germany)

2013-11-29

Diffusion of particles in porous media often shows subdiffusive behavior. Here, we analyze the dynamics of particles exhibiting an orientation. The features we focus on are geometrical restrictions and the dynamical consequences of the interactions between the local surrounding structure and the particle orientation. This interaction can lead to particles getting temporarily stuck in parts of the structure. Modeling this interaction by a particular random walk dynamics on fractal structures we find that the random walk dimension is not affected while the diffusion constant shows a variety of interesting and surprising features.

Diffusion of oriented particles in porous media

International Nuclear Information System (INIS)

Haber, René; Prehl, Janett; Herrmann, Heiko; Hoffmann, Karl Heinz

2013-01-01

Diffusion of particles in porous media often shows subdiffusive behavior. Here, we analyze the dynamics of particles exhibiting an orientation. The features we focus on are geometrical restrictions and the dynamical consequences of the interactions between the local surrounding structure and the particle orientation. This interaction can lead to particles getting temporarily stuck in parts of the structure. Modeling this interaction by a particular random walk dynamics on fractal structures we find that the random walk dimension is not affected while the diffusion constant shows a variety of interesting and surprising features.

Effects of metallic Ti particles on the aging behavior and the influenced mechanical properties of squeeze-cast (SiCp+Ti)/7075Al hybrid composites

International Nuclear Information System (INIS)

Liu, Yixiong; Chen, Weiping; Yang, Chao; Zhu, Dezhi; Li, Yuanyuan

2015-01-01

The effects of metallic Ti particles on the aging behavior of squeeze-cast (SiC p +Ti)/7075Al hybrid composites and the mechanical properties of the aging treated composites were investigated. Results shown that the precipitation hardening of the hybrid composites during aging processes was delayed due to the segregation of solute Mg atoms in the vicinity of the Ti particles even though the activation energy of the η′ precipitates in the hybrid composites was reduced when compared with the Ti particle-free composites. The segregation of the solute Mg atoms was facilitated as a result of the high diffusivity paths formed by the generated dislocations in the matrix induced by the thermal misfit between the SiC particle and the matrix. The smaller activation energy for the hybrid composite may attribute to a significant reduction in the nucleation rate of the dislocation nucleated η′ precipitates compared with the Ti particle-free composite. After aging treated under the optimum aging conditions, the tensile strength of both composites was improved because of the precipitation hardening of the matrix alloy. In contrast with the reduced ductility of the traditional Ti particle-free composites after aging treatment, the ductility of the Ti particle-containing composites was improved as a result of the strengthened interfaces between the Ti particles and the matrix alloy

Numerical Study of Particle Interaction in Gas-Particle and Liquid-Particle Flows: Part II Particle Response

Directory of Open Access Journals (Sweden)

K. Mohanarangam

2009-09-01

Full Text Available In this paper the numerical model, which was presented in the first paper (Mohanarangam & Tu; 2009 of this series of study, is employed to study the different particle responses under the influence of two carrier phases namely the gas and the liquid. The numerical model takes into consideration the turbulent behaviour of both the carrier and the dispersed phases, with additional equations to take into account the combined fluid particle behaviour, thereby effecting a two-way coupling. The first paper in this series showed the distinct difference in particulate response both at the mean as well as at the turbulent level for two varied carrier phases. In this paper further investigation has been carried out over a broad range of particle Stokes number to further understand their behaviour in turbulent environments. In order to carry out this prognostic study, the backward facing step geometry of Fessler and Eaton (1999 has been adopted, while the inlet conditions for the carrier as well as the particle phases correspond to that of the experiments of Founti and Klipfel (1998. It is observed that at the mean velocity level the particulate velocities increased with a subsequent increase in the Stokes number for both the GP (Gas-Particle as well as the LP (Liquid-Particle flow. It was also observed that across the Stokes number there was a steady increase in the particulate turbulence for the GP flows with successive increase in Stokes number. However, for the LP flows, the magnitude of the increase in the particulate turbulence across the increasing of Stokes number is not as characteristic as the GP flow. Across the same sections for LP flows the majority of the trend shows a decrease after which they remain more or less a constant.

Particles size distribution effect on 3D packing of nanoparticles in to a bounded region

International Nuclear Information System (INIS)

Farzalipour Tabriz, M.; Salehpoor, P.; Esmaielzadeh Kandjani, A.; Vaezi, M. R.; Sadrnezhaad, S. K.

2007-01-01

In this paper, the effects of two different Particle Size Distributions on packing behavior of ideal rigid spherical nanoparticles using a novel packing model based on parallel algorithms have been reported. A mersenne twister algorithm was used to generate pseudo random numbers for the particles initial coordinates. Also, for this purpose a nano sized tetragonal confined container with a square floor (300 * 300 nm) were used in this work. The Andreasen and the Lognormal Particle Size Distributions were chosen to investigate the packing behavior in a 3D bounded region. The effects of particle numbers on packing behavior of these two Particle Size Distributions have been investigated. Also the reproducibility and the distribution of packing factor of these Particle Size Distributions were compared

Microscopic analysis of Hopper flow with ellipsoidal particles

Science.gov (United States)

Liu, Sida; Zhou, Zongyan; Zou, Ruiping; Pinson, David; Yu, Aibing

2013-06-01

Hoppers are widely used in process industries. With such widespread application, difficulties in achieving desired operational behaviors have led to extensive experimental and mathematical studies in the past decades. Particularly, the discrete element method has become one of the most important simulation tools for design and analysis. So far, most studies are on spherical particles for computational convenience. In this work, ellipsoidal particles are used as they can represent a large variation of particle shapes. Hopper flow with ellipsoidal particles is presented highlighting the effect of particle shape on the microscopic properties.

Numerical analysis of jet breakup behavior using particle method

International Nuclear Information System (INIS)

Shibata, Kazuya; Koshizuka, Seiichi; Oka, Yoshiaki

2002-01-01

A continuous jet changes to droplets where jet breakup occurs. In this study, two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows. The continuous fluid surrounding the jet is neglected. Dependencies of the jet breakup length on the Weber number and the Froude number agree with the experiment. The size distribution of droplets is in agreement with the Nukiyama-Tanasawa distribution which has been widely used as an experimental correlation. Effects of the Weber number and the Froude number on the size distribution are also obtained. (author)

Spin analysis of supersymmetric particles

International Nuclear Information System (INIS)

Choi, S.Y.; Martyn, H.U.

2006-12-01

The spin of supersymmetric particles can be determined at e + e - colliders unambiguously. This is demonstrated for a characteristic set of non-colored supersymmetric particles -- smuons, selectrons, and charginos/neutralinos. The analysis is based on the threshold behavior of the excitation curves for pair production in e + e - collisions, the angular distribution in the production process and decay angular distributions. In the first step we present the observables in the helicity formalism for the supersymmetric particles. Subsequently we confront the results with corresponding analyses of Kaluza-Klein particles in theories of universal extra space dimensions which behave distinctly different from supersymmetric theories. It is shown in the third step that a set of observables can be designed which signal the spin of supersymmetric particles unambiguously without any model assumptions. Finally in the fourth step it is demonstrated that the determination of the spin of supersymmetric particles can be performed experimentally in practice at an e + e - collider. (orig.)

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.

Understanding the transformation, speciation, and hazard potential of copper particles in a model septic tank system using zebrafish to monitor the effluent.

Science.gov (United States)

Lin, Sijie; Taylor, Alicia A; Ji, Zhaoxia; Chang, Chong Hyun; Kinsinger, Nichola M; Ueng, William; Walker, Sharon L; Nel, André E

2015-02-24

Although copper-containing nanoparticles are used in commercial products such as fungicides and bactericides, we presently do not understand the environmental impact on other organisms that may be inadvertently exposed. In this study, we used the zebrafish embryo as a screening tool to study the potential impact of two nano Cu-based materials, CuPRO and Kocide, in comparison to nanosized and micron-sized Cu and CuO particles in their pristine form (0-10 ppm) as well as following their transformation in an experimental wastewater treatment system. This was accomplished by construction of a modeled domestic septic tank system from which effluents could be retrieved at different stages following particle introduction (10 ppm). The Cu speciation in the effluent was identified as nondissolvable inorganic Cu(H2PO2)2 and nondiffusible organic Cu by X-ray diffraction, inductively coupled plasma mass spectrometry (ICP-MS), diffusive gradients in thin-films (DGT), and Visual MINTEQ software. While the nanoscale materials, including the commercial particles, were clearly more potent (showing 50% hatching interference above 0.5 ppm) than the micron-scale particulates with no effect on hatching up to 10 ppm, the Cu released from the particles in the septic tank underwent transformation into nonbioavailable species that failed to interfere with the function of the zebrafish embryo hatching enzyme. Moreover, we demonstrate that the addition of humic acid, as an organic carbon component, could lead to a dose-dependent decrease in Cu toxicity in our high content zebrafish embryo screening assay. Thus, the use of zebrafish embryo screening, in combination with the effluents obtained from a modeled exposure environment, enables a bioassay approach to follow the change in the speciation and hazard potential of Cu particles instead of difficult-to-perform direct particle tracking.

Understanding Social Learning Behaviors via a Virtual Field Trip

Directory of Open Access Journals (Sweden)

Xin Bai

2014-06-01

Full Text Available This is a multidisciplinary study investigating how a virtual rather than face-to-face field trip can be conducted in a real-world setting and how students respond to such a social learning opportunity. Our participants followed a story of a stroke patient at her virtual home and in a virtual hospital via a teaching vignette. They were then given a new case and got on a virtual trip via a multiuser virtual environment. They played the roles of patients, relatives, doctors, or nurses, experiencing the emotional, physical, or social impacts those stakeholders may go through. Our study finds the overall participation of the Virtual Group is 50% more than the Text Group. Although the Virtual Group generates much more nodes in total, they focused much less on knowledge sharing and comparing than the Text Group (46 vs. 67, but more on other higher-level aspects of social interactions, such as knowledge discovery (57 vs. 42, co-construction (66 vs. 39, testing and modification (58 vs. 24 and application of newly constructed meaning (60 vs. 16. Analysis of students’ virtual field activities and in-depth discussions of important issues implied are included to help understand social learning behaviors during a virtual field trip. Sustainability of such systems is discussed.

Size measurement of radioactive aerosol particles in intense radiation fields using wire screens and imaging plates

Energy Technology Data Exchange (ETDEWEB)

Oki, Yuichi; Tanaka, Toru; Takamiya, Koichi; Ishi, Yoshihiro; UesugI, Tomonori; Kuriyama, Yasutoshi; Sakamoto, Masaaki; Ohtsuki, Tsutomu [Kyoto University Research Reactor Institute, Osaka (Japan); Nitta, Shinnosuke [Graduate School of Engineering, Kyoto University, Kyoto (Japan); Osada, Naoyuki [Advanced Science Research Center, Okayama University, Okayama (Japan)

2016-09-15

Very fine radiation-induced aerosol particles are produced in intense radiation fields, such as high-intensity accelerator rooms and containment vessels such as those in the Fukushima Daiichi nuclear power plant (FDNPP). Size measurement of the aerosol particles is very important for understanding the behavior of radioactive aerosols released in the FDNPP accident and radiation safety in high-energy accelerators. A combined technique using wire screens and imaging plates was developed for size measurement of fine radioactive aerosol particles smaller than 100 nm in diameter. This technique was applied to the radiation field of a proton accelerator room, in which radioactive atoms produced in air during machine operation are incorporated into radiation-induced aerosol particles. The size of 11C-bearing aerosol particles was analyzed using the wire screen technique in distinction from other positron emitters in combination with a radioactive decay analysis. The size distribution for 11C-bearing aerosol particles was found to be ca. 70 μm in geometric mean diameter. The size was similar to that for 7Be-bearing particles obtained by a Ge detector measurement, and was slightly larger than the number-based size distribution measured with a scanning mobility particle sizer. The particle size measuring method using wire screens and imaging plates was successfully applied to the fine aerosol particles produced in an intense radiation field of a proton accelerator. This technique is applicable to size measurement of radioactive aerosol particles produced in the intense radiation fields of radiation facilities.