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1

PRETREATMENT AND FRACTIONATION OF CORN STOVER BY AMMONIA RECYCLE PERCOLATION PROCESS. (R831645)  

EPA Science Inventory

Corn stover was pretreated with aqueous ammonia in a flow-through column reactor, a process termed as Ammonia Recycle Percolation (ARP). The aqueous ammonia causes swelling and efficient delignification of biomass at high temperatures. The ARP process solubilizes abou...

2

Ammonia recycling enables sustainable operation of bioelectrochemical systems.  

PubMed

Ammonium (NH4(+)) migration across a cation exchange membrane is commonly observed during the operation of bioelectrochemical systems (BES). This often leads to anolyte acidification (pH <5.5) and complete inactivation of biofilm electroactivity. Without using conventional pH controls (dosage of alkali or pH buffers), the present study revealed that anodic biofilm activity (current) could be sustained if recycling of ammonia (NH3) was implemented. A simple gas-exchange apparatus was designed to enable continuous recycling of NH3 (released from the catholyte at pH >10) from the cathodic headspace to the acidified anolyte. Results indicated that current (110 mA or 688 Am(-3) net anodic chamber volume) was sustained as long as the NH3 recycling path was enabled, facilitating continuous anolyte neutralization with the recycled NH3. Since the microbial current enabled NH4(+) migration against a strong concentration gradient (~10-fold), a novel way of ammonia recovery from wastewaters could be envisaged. PMID:23774293

Cheng, Ka Yu; Kaksonen, Anna H; Cord-Ruwisch, Ralf

2013-09-01

3

Seasonal ammonia losses from spray-irrigation with secondary-treated recycled water.  

PubMed

This work examines ammonia volatilization associated with agricultural irrigation employing recycled water. Effluent from a secondary wastewater treatment plant was applied using a center pivot irrigation system on a 12 ha agricultural site in Palmdale, California. Irrigation water was captured in shallow pans and ammonia concentrations were quantified in four seasonal events. The average ammonia loss ranged from 15 to 35% (averaging 22%) over 2-h periods. Temporal mass losses were well-fit using a first-order model. The resulting rate constants correlated primarily with temperature and secondarily with wind speed. The observed application rates and timing were projected over an entire irrigation season using meteorological time series data from the site, which yielded volatilization estimates of 0.03 to 0.09 metric tons NH(3)-N/ha per year. These rates are consistent with average rates (0.04 to 0.08 MT NH(3)-N/ha per year) based on 10 to 20 mg NH(3)-N/L effluent concentrations and a 22% average removal. As less than 10% of the treated effluent in California is currently reused, there is potential for this source to increase, but the increase may be offset by a corresponding reduction in synthetic fertilizers usage. This point is a factor for consideration with respect to nutrient management using recycled water. PMID:22277226

Saez, Jose A; Harmon, Thomas C; Doshi, Sarika; Guerrero, Francisco

2012-01-01

4

AMMONIA  

EPA Science Inventory

This document summarizes the available information on ammonia as it relates to its effects on man and his environment. Ammonia is a ubiquitous substance and is known widely as a household cleaning agent and as a fertilizer. It plays an important role in the nitrogen cycle--in the...

5

Process modeling of an advanced NH? abatement and recycling technology in the ammonia-based CO? capture process.  

PubMed

An advanced NH3 abatement and recycling process that makes great use of the waste heat in flue gas was proposed to solve the problems of ammonia slip, NH3 makeup, and flue gas cooling in the ammonia-based CO2 capture process. The rigorous rate-based model, RateFrac in Aspen Plus, was thermodynamically and kinetically validated by experimental data from open literature and CSIRO pilot trials at Munmorah Power Station, Australia, respectively. After a thorough sensitivity analysis and process improvement, the NH3 recycling efficiency reached as high as 99.87%, and the NH3 exhaust concentration was only 15.4 ppmv. Most importantly, the energy consumption of the NH3 abatement and recycling system was only 59.34 kJ/kg CO2 of electricity. The evaluation of mass balance and temperature steady shows that this NH3 recovery process was technically effective and feasible. This process therefore is a promising prospect toward industrial application. PMID:24850444

Li, Kangkang; Yu, Hai; Tade, Moses; Feron, Paul; Yu, Jingwen; Wang, Shujuan

2014-06-17

6

Recycling  

NSDL National Science Digital Library

You will be learning all about recycling and asking questions as you learn more about recycling. Afterward, you will be making recycling bins that we will use in our classroom. Click on each of the different links and research about recycling. Find out what recycling is, what can be recycled, and why we should recycle. As you find information, add it to the "describing wheel" that is given to you by Ms. Pollak. Answer the main question: What is recycling? Come ...

sgp0002

2010-03-27

7

Recycling.  

ERIC Educational Resources Information Center

Discusses the range of benefits resulting from recycling efforts and projects. Presents information and data related to the recycling of metals, cans, paper, fans, and plastics. Suggestions for motivating and involving youth in recycling programs are also offered. (ML)

Sinker, Barbara

1986-01-01

8

Recycling  

NSDL National Science Digital Library

What objects can be recycled? 1. Click on link. Watch video. Recycle Guy Video 2. Click on link. Watch video. Talking Trash Video 3. Click on link. Watch video. Recycling At School Video 4. Click on link. Play game. Star Fall Recycling Game 5. Click on link. Play game. National Geographic Recycling Game 6. Click on link. Ask Ms. Owens how to do it. Things We Recycle Chart 7. Please see Miss Owens for instructions on the following ...

2011-04-07

9

Recycle  

SciTech Connect

;Contents: The Problem; What`s In Our Trash; Where Does Trash Go; Where Does Our Trash Go; The Solution; What Is Recycling; Why Should We Recycle; A National Goal of 25%; What Can We Recycle; What Do We Do With Our Recyclables.

NONE

1988-10-01

10

Marketing percolation  

NASA Astrophysics Data System (ADS)

A percolation model is presented, with computer simulations for illustrations, to show how the sales of a new product may penetrate the consumer market. We review the traditional approach in the marketing literature, which is based on differential or difference equations similar to the logistic equation (Bass, Manage. Sci. 15 (1969) 215). This mean-field approach is contrasted with the discrete percolation on a lattice, with simulations of “social percolation” (Solomon et al., Physica A 277 (2000) 239) in two to five dimensions giving power laws instead of exponential growth, and strong fluctuations right at the percolation threshold.

Goldenberg, J.; Libai, B.; Solomon, S.; Jan, N.; Stauffer, D.

2000-09-01

11

Elimination of phenols, ammonia and cyanide in wash water from biomass gasification, and nitrogen recycling using planted trickling filters.  

PubMed

Trickling filters were used to treat wash water from a wood gasifier. This wash water contained toxic substances such as ammonium, cyanide, phenols, and PAH. The goal was to develop a system that degraded toxic substances, and achieved full nitrification of ammonia. A 1 kW model wood gasifier plant delivered wash water for the experiments, which was standardised to a conductivity of 3 mS/cm by dilution. Toxicity was assessed by bacterial luminescence detection, germination test with cress (Lepidium sativum), and pot plants cultivated in a hydroponic setup irrigated continuously with the wastewater. Treatment experiments were done in both planted and unplanted trickling filters. Plant yield was similar to conventional hydroponic production systems. The trickling filters achieved complete detoxification of phenol, PAH and cyanide as well as full nitrification. The specific elimination rates were 100 g m(-3) Leca d(-1) for phenols and 90 g m(-3) Leca d(-1) for ammonium in planted systems. In unplanted trickling filters circulated for 63 h, phenol concentration decreased from 83.5 mg/L to 2.5 mg/L and cyanide concentration from 0.32 mg/L to 0.02 mg/L. PAH concentrations were reduced from 3,050 microg/L to 0.89 microg/L within 68 days. The assays demonstrated the feasibility of using the technique to construct a treatment system in a partially closed circulation for gasifier wash water. The principal advantage is to convert toxic effluents from biomass gasifiers into a non-toxic, nitrogen-rich fertiliser water, enabling subsequent use in plant production and thus income generation. However, the questions of long-term performance and possible accumulation of phenols and heavy metals in the produce still have to be studied. PMID:19955650

Graber, Andreas; Skvarc, Robert; Junge-Berberovi?, Ranka

2009-01-01

12

Threshold of hierarchical percolating systems  

NASA Astrophysics Data System (ADS)

Many modern nanostructured materials and doped polymers are morphologically too complex to be interpreted by classical percolation theory. Here, we develop the concept of a hierarchical percolating (percolation-within-percolation) system to describe such complex materials and illustrate how to generalize the conventional percolation to double-level percolation. Based on Monte Carlo simulations, we find that the double-level percolation threshold is close to, but definitely larger than, the product of the local percolation thresholds for the two enclosed single-level systems. The deviation may offer alternative insights into physics concerning infinite clusters and open up new research directions for percolation theory.

Li, Jiantong; Ray, Biswajit; Alam, Muhammad A.; Östling, Mikael

2012-02-01

13

Continuum percolation with tunneling  

NASA Astrophysics Data System (ADS)

Classical percolation theory ignores the possibility of quantum tunneling, which is important for transport on the nanoscale. Here we show that the electrical conductance of a two-dimensional percolating-tunneling system exhibits an exponential dependence on surface coverage, which is in contrast to the classically expected power law, and that there is no evidence for an intrinsic threshold for tunneling conduction. We then show that the percolating-tunneling system is identical to that of an equivalent system of point defects, hence creating a link between continuum percolation and the theory of hopping conduction in semiconductors.

Fostner, Shawn; Brown, Richard; Carr, James; Brown, Simon A.

2014-02-01

14

Fat fractal percolation and k-fractal percolation Erik Bromana  

E-print Network

Fat fractal percolation and k-fractal percolation Erik Bromana Tim van de Brugb Federico Camiab fractal percolation model. In the k-fractal percolation model, the d-dimensional unit cube is divided . This is analogous to the result of Falconer and Grimmett in [8] that the critical value for Mandelbrot fractal

Meester, Ronald

15

Percolation on sparse networks  

E-print Network

We study percolation on networks, which is widely used as a model of the resilience of networked systems such as the Internet to attack or failure and as a simple model of the spread of disease over human contact networks. We reformulate percolation as a message passing process and use the resulting equations to show, among other things, that for sparse networks, which includes most networks observed in the real world, the percolation threshold is given by the inverse of the leading eigenvalue of the so-called non-backtracking matrix. Like most message passing calculations, our results are exact on networks that have few small loops but, as we show, they also provide bounds on the percolation behavior of networks that do contain loops.

Karrer, Brian; Zdeborová, Lenka

2014-01-01

16

Unstable supercritical discontinuous percolation transitions  

NASA Astrophysics Data System (ADS)

The location and nature of the percolation transition in random networks is a subject of intense interest. Recently, a series of graph evolution processes have been introduced that lead to discontinuous percolation transitions where the addition of a single edge causes the size of the largest component to exhibit a significant macroscopic jump in the thermodynamic limit. These processes can have additional exotic behaviors, such as displaying a “Devil's staircase” of discrete jumps in the supercritical regime. Here we investigate whether the location of the largest jump coincides with the percolation threshold for a range of processes, such as Erd?s-Rényipercolation, percolation via edge competition and via growth by overtaking. We find that the largest jump asymptotically occurs at the percolation transition for Erd?s-Rényiand other processes exhibiting global continuity, including models exhibiting an “explosive” transition. However, for percolation processes exhibiting genuine discontinuities, the behavior is substantially richer. In percolation models where the order parameter exhibits a staircase, the largest discontinuity generically does not coincide with the percolation transition. For the generalized Bohman-Frieze-Wormald model, it depends on the model parameter. Distinct parameter regimes well in the supercritical regime feature unstable discontinuous transitions—a novel and unexpected phenomenon in percolation. We thus demonstrate that seemingly and genuinely discontinuous percolation transitions can involve a rich behavior in supercriticality, a regime that has been largely ignored in percolation.

Chen, Wei; Cheng, Xueqi; Zheng, Zhiming; Chung, Ning Ning; D'Souza, Raissa M.; Nagler, Jan

2013-10-01

17

Electrical Percolation Based Biosensors  

PubMed Central

A new approach to label free biosensing has been developed based on the principle of “electrical percolation”. In electrical percolation, long-range electrical connectivity is formed in randomly oriented and distributed systems of discrete elements. By applying this principle to biological interactions, it is possible to measure biological components both directly and electronically. The main element for electrical percolation biosensor is the biological semiconductor (BSC) which is a multi-layer 3-D carbon nanotube-antibody network. In the BSC, molecular interactions, such as binding of antigens to the antibodies, disrupt the network continuity causing increased resistance of the network. BSCs can be fabricated by immobilizing conducting elements, such as pre-functionalized single-walled carbon nanotubes (SWNTs)-antibody complex, directly onto a substrate, such as a Poly(methyl methacrylate) (PMMA) surface (also known as plexi-glass or Acrylic). BSCs have been demonstrated for direct (label-free) electronic measurements of antibody-antigen binding using SWNTs. If the concentration of the SWNT network is slightly above the electrical percolation threshold, then binding of a specific antigen to the pre-functionalized SWNT dramatically increases the electrical resistance due to changes in the tunneling between the SWNTs. Using anti-Staphylococcal enterotoxin B (SEB) IgG as a “gate” and SEB as an “actuator”, it was demonstrated that the BSC was able to detect SEB at concentrations of 1 ng/ml. Based on this concept, an automated configuration for BSCs is described here that enables real time continuous detection. The new BSC configuration may permit assembly of multiple sensors on the same chip to create “Biological Central Processing Units (CPUs)” with multiple biological elements, capable of processing and sorting out information on multiple analytes simultaneously. PMID:24041756

Bruck, Hugh Alan; Yang, Minghui; Kostov, Yordan; Rasooly, Avraham

2013-01-01

18

Indistinguishability of Percolation Clusters  

E-print Network

We show that when percolation produces infinitely many infinite clusters on a Cayley graph, one cannot distinguish the clusters from each other by any invariantly defined property. This implies that uniqueness of the infinite cluster is equivalent to non-decay of connectivity (a.k.a. long-range order). We then derive applications concerning uniqueness in Kazhdan groups and in wreath products, and inequalities for $p_u$.

Russell Lyons; Oded Schramm

1998-11-29

19

Forest Fires and Percolation  

NSDL National Science Digital Library

This is the description and instructions as well as a link for the "Forest Fires and Percolation" applet. It builds a background with a "hands-on" activity for the students which then leads to the applet itself. The applet is a game where the object is to save as many trees from the forest fire as possible. It shows the spread of a fire with the variable of density and the probability of the number of surviving trees.

Mcgath, Gary; Trunfio, Paul

2009-12-14

20

k Clique Percolation and Clustering  

Microsoft Academic Search

\\u000a We summarise recent results connected to the concept of k-clique percolation. This approach can be considered as a generalisation of edge percolation with a great potential as a community\\u000a finding method in real-world graphs. We present a detailed study of the critical point for the appearance of a giant k-clique percolation cluster in the Erd?s-Rényi-graph. The observed transition is continuous

Gergely Palla; Dániel Ábel; Illés J. Farkas; Péter Pollner; Imre Derényi; Tamás Vicsek

21

Space-filling percolation  

NASA Astrophysics Data System (ADS)

A region of two-dimensional space has been filled randomly with a large number of growing circular disks allowing only a "slight" overlapping among them just before their growth stops. More specifically, each disk grows from a nucleation center that is selected at a random location within the uncovered region. The growth rate ? is a continuously tunable parameter of the problem which assumes a specific value while a particular pattern of disks is generated. When a growing disk overlaps for the first time with at least one other disk, its growth is stopped and is said to be frozen. In this paper we study the percolation properties of the set of frozen disks. Using numerical simulations we present evidence for the following: (i) The order parameter appears to jump discontinuously at a certain critical value of the area coverage; (ii) the width of the window of the area coverage needed to observe a macroscopic jump in the order parameter tends to vanish as ? ?0; and on the contrary (iii) the cluster size distribution has a power-law-decaying functional form. While the first two results are the signatures of a discontinuous transition, the third result is indicative of a continuous transition. Therefore we refer to this transition as a sharp but continuous transition similar to what has been observed in the recently introduced Achlioptas process of explosive percolation. It is also observed that in the limit of ? ?0, the critical area coverage at the transition point tends to unity, implying that the limiting pattern is space filling. In this limit, the fractal dimension of the pore space at the percolation point has been estimated to be 1.42(10) and the contact network of the disk assembly is found to be a scale-free network.

Chakraborty, Abhijit; Manna, S. S.

2014-03-01

22

Quantum thermalization via percolation  

E-print Network

We employ a minimal model of a bi-partite $N$-boson system, where $\\hbar=1/N$ plays the role of the Planck constant, to study the thermalization of the constituent subsystems. We find that the rate of relaxation towards equilibrium violates the standard linear-response (Kubo) formulation, even when the underlying dynamics is highly chaotic. This anomaly originates from an $\\hbar$-dependent sparsity of the underlying quantum network of transitions. Consequently the relaxation rate acquires an anomalous $\\hbar$ dependence that reflects percolation-like dynamics in energy space. This {\\em dynamical} anomaly is distinct from lack of quantum ergodicity due to classical or quantum localization.

Christine Khripkov; Amichay Vardi; Doron Cohen

2014-06-26

23

CMOP Undergraduate Intern Mentoring Opportunity Project Title: Nitrification Potential and Niche Diversification of Ammonia Oxidizing Archaea in  

E-print Network

. They are essential for recycling nutrients through global biogeochemical cycles, which ultimately impacts our lives the mineralization of organic matter to the recycling of nitrogen to the atmosphere). Ammonia oxidation is solely mediated by autotrophic ammonia oxidizing bacteria (AOB) and the recently-discovered ammonia oxidizing

24

Scaling theory of percolation clusters  

Microsoft Academic Search

For beginners: This review tries to explain percolation through the cluster properties; it can also be used as an introduction to critical phenomena at other phase transitions for readers not familiar with scaling theory. In percolation each site of a periodic lattice is randomly occupied with probability p or empty with probability 1-p. An s-cluster is a group of s

D. Stauffer

1979-01-01

25

Local Bootstrap Percolation  

E-print Network

We study a variant of bootstrap percolation in which growth is restricted to a single active cluster. Initially there is a single active site at the origin, while other sites of Z^2 are independently occupied with small probability p, otherwise empty. Subsequently, an empty site becomes active by contact with 2 or more active neighbors, and an occupied site becomes active if it has an active site within distance 2. We prove that the entire lattice becomes active with probability exp[alpha(p)/p], where alpha(p) is between -pi^2/9 + c sqrt p and pi^2/9 + C sqrt p (-log p)^3. This corrects previous numerical predictions for the scaling of the correction term.

Janko Gravner; Alexander E. Holroyd

2008-06-13

26

Development of Vapor-Phase Catalytic Ammonia Removal System  

NASA Technical Reports Server (NTRS)

A report describes recent accomplishments of a continuing effort to develop the vapor-phase catalytic ammonia removal (VPCAR) process for recycling wastewater for consumption by humans aboard a spacecraft in transit to Mars.

Flynn, Michael; Fisher, John; Kiss, Mark; Borchers, Bruce; Tleimat, Badawi; Tleimat, Maher; Quinn, Gregory; Fort, James; Nalette, Tim; Baker, Gale; Genovese, Joseph

2007-01-01

27

Weak percolation on multiplex networks  

NASA Astrophysics Data System (ADS)

Bootstrap percolation is a simple but nontrivial model. It has applications in many areas of science and has been explored on random networks for several decades. In single-layer (simplex) networks, it has been recently observed that bootstrap percolation, which is defined as an incremental process, can be seen as the opposite of pruning percolation, where nodes are removed according to a connectivity rule. Here we propose models of both bootstrap and pruning percolation for multiplex networks. We collectively refer to these two models with the concept of "weak" percolation, to distinguish them from the somewhat classical concept of ordinary ("strong") percolation. While the two models coincide in simplex networks, we show that they decouple when considering multiplexes, giving rise to a wealth of critical phenomena. Our bootstrap model constitutes the simplest example of a contagion process on a multiplex network and has potential applications in critical infrastructure recovery and information security. Moreover, we show that our pruning percolation model may provide a way to diagnose missing layers in a multiplex network. Finally, our analytical approach allows us to calculate critical behavior and characterize critical clusters.

Baxter, Gareth J.; Dorogovtsev, Sergey N.; Mendes, José F. F.; Cellai, Davide

2014-04-01

28

Random wave functions and percolation  

E-print Network

Recently it was conjectured that nodal domains of random wave functions are adequately described by critical percolation theory. In this paper we strengthen this conjecture in two respects. First, we show that, though wave function correlations decay slowly, a careful use of Harris' criterion confirms that these correlations are unessential and nodal domains of random wave functions belong to the same universality class as non critical percolation. Second, we argue that level domains of random wave functions are described by the non-critical percolation model.

E. Bogomolny; C. Schmit

2007-08-31

29

Coalescence and percolation in thin metal films  

Microsoft Academic Search

Metals thermally evaporated onto warm insulating substrates evolve to the thin-film state via the morphological sequence: compact islands, elongated islands, percolation, hole filling, and finally the thin-film state. The coverage at which the metal percolates (pc) is often considerably higher than that predicted by percolation models, such as inverse swiss cheese or lattice percolation. Using a simple continuum model, we

X. Yu; P. M. Duxbury; G. Jeffers; M. A. Dubson

1991-01-01

30

Stacked triangular lattice: Percolation properties  

NASA Astrophysics Data System (ADS)

The stacked triangular lattice has the shape of a triangular prism. In spite of being considered frequently in solid-state physics and materials science, its percolation properties have received little attention. We investigate several nonuniversal percolation properties on this lattice using Monte Carlo simulation. We show that the percolation threshold is pcbond=0.18602±0.00002 for bonds and pcsite=0.26240±0.00005 for sites. The number of clusters at the threshold per site is ncbond=0.28458±0.00005 and ncsite=0.03998±0.00005. The stacked triangular lattice is a convenient choice to study the RGB model [Schrenk , Sci. Rep.10.1038/srep00751 2, 751 (2012)]. We present results on this model and its scaling behavior at the percolation threshold.

Schrenk, K. J.; Araújo, N. A. M.; Herrmann, H. J.

2013-03-01

31

Percolation in the classical blockmodel  

NASA Astrophysics Data System (ADS)

Classical blockmodel is known as the simplest among models of networks with community structure. The model can be also seen as an extremely simply example of interconnected networks. For this reason, it is surprising that the percolation transition in the classical blockmodel has not been examined so far, although the phenomenon has been studied in a variety of much more complicated models of interconnected and multiplex networks. In this paper we derive the self-consistent equation for the size the global percolation cluster in the classical blockmodel. We also find the condition for percolation threshold which characterizes the emergence of the giant component. We show that the discussed percolation phenomenon may cause unexpected problems in a simple optimization process of the multilevel network construction. Numerical simulations confirm the correctness of our theoretical derivations.

Bujok, Maksymilian; Fronczak, Piotr; Fronczak, Agata

2014-09-01

32

Core percolation on complex networks  

NASA Astrophysics Data System (ADS)

As a fundamental structural transition in complex networks, core percolation is related to a wide range of important problems, including combinatorial optimizations and network controllability. Yet, previous theoretical studies of core percolation have been focusing on the classical Erdos-Rényi random networks with Poisson degree distribution, which are quite unlike many real-world networks with scale-free or fat-tailed degree distributions. Here we show that core percolation can be analytically studied for complex networks with arbitrary degree distributions. We derive the condition for core percolation and find that purely scale-free networks have no core for any degree exponents. We show that for undirected networks if core percolation occurs then it is always continuous while for directed networks it becomes discontinuous (and hybrid) if the in- and out-degree distributions differ. We also find that core percolations on undirected and directed networks have completely different critical exponents associated with their critical singularities. Finally, we apply our theory to real-world directed networks and find, surprisingly, that they often have much larger core sizes as compared to random models.

Liu, Yang-Yu; Csóka, Endre; Zhou, Haijun; Pósfai, Márton

2013-03-01

33

Recycling, Inc.  

ERIC Educational Resources Information Center

Suggestions for creating a successful office recycling system are enumerated from start up plans to waste reduction and paper recycling. Contact information for recycling equipment, potential buyers of recycled materials, recycled products for purchase, and ideas for promotion and education of staff are included. (MCO)

Martin, Amy

1992-01-01

34

Classical and Quantum Correlated Percolation  

NASA Astrophysics Data System (ADS)

Percolation is the study of connected structures in disordered networks. As edges are randomly and independently added to the network, clusters of neighboring edges grow in size until there ultimately exists a percolating cluster. The emergence of this percolating cluster exhibits properties of a continuous phase transition. The simplicity of uncorrelated percolation makes it the Ising model of connectivity-driven phase transitions. This thesis documents a quest to go beyond uncorrelated percolation and investigate transitions in correlated percolation models where there are constraints on the addition of edges (or vertices). Such constraints are inspired by glassy and jamming systems, for example. More specifically, we discuss several correlated percolation models, the k-core model on random graphs, and the spiral and counter-balance models in two-dimensions—all exhibiting discontinuous transitions yet with diverging correlation lengths—in an effort to identify the needed ingredients for such a novel transition. We also construct mixtures of these models to interpolate between a continuous transition and a discontinuous transition to search for tricriticality. Then, to capture both the local and global mechanical stability properties of disordered particle packings, we work towards building jamming graphs via the Henneberg construction. This construction is another example of a correlated percolation model since there are constraints on the addition (and removal) of edges. Jamming graphs provide for a more rigorous way to define the jamming transition for repulsive soft spheres as well as a starting point to understanding how the local and global mechanical properties interact and characterize the system. In addition, we study quantum transport properties along these disordered networks with correlations in the connectivity and investigate how such correlations affect, for example, the transition from insulator to metal as the percolating cluster emerges. Treating each occupied edge as a quantum scatterer and invoking the random phase approximation, we find for k = 3-core networks on the Bethe lattice (a connected, loop-free graph) that the random first-order phase transition in the connectivity also drives the onset of quantum conduction giving rise to a new type of metal-insulator transition. Finally, we conduct level spacing analysis to go beyond the random phase approximation. This analysis reiterates our findings of a new random first-order phase transition in the world of disorder-driven metal-insulator transitions.

Cao, Liang

35

Percolation phenomena by computer simulation  

SciTech Connect

The microstructure of cement-based materials is determined by the chemical nature and amounts of the original constituents, and the succeeding chemical hydration process. An aspect of the microstructure that is important in determining properties is how these products are arranged topologically in space. In particular, how each product phase becomes connected or disconnected (percolation threshold) plays a large role in such important properties of these porous materials as ionic diffusion, electrical conductivity, and fluid permeability. We use computer models to determine the important percolation thresholds in portland cement-based materials, covering connectivity phenomena from length scales of micrometers to meters. We show how the overall behavior of this material, from processing to final use, may be described by its percolation thresholds.

Garboczi, E.J.; Bentz, D.P. [National Institute of Standards and Technology, Gaithersburg, MD (United States)

1995-12-31

36

Linear algebra and bootstrap percolation  

E-print Network

In $\\HH$-bootstrap percolation, a set $A \\subset [n]$ of initially `infected' vertices spreads by infecting vertices which are the only uninfected vertex in an edge of the hypergraph $\\HH \\subset \\P(n)$. A particular case of this is the $H$-bootstrap process, in which $\\HH$ encodes copies of $H$ in a graph $G$. We find the minimum size of a set $A$ that leads to complete infection when $G$ is a power of a complete graph and $H$ is a hypercube. The proof uses linear algebra, a technique that is new in bootstrap percolation, although standard in the study of weakly saturated graphs, which are equivalent to (edge) $H$-bootstrap percolation on a complete graph.

Balogh, József; Morris, Robert; Riordan, Oliver

2011-01-01

37

Responsible recycling  

SciTech Connect

The issues that affect the recycling of lead-acid batteries and the challenges that this issue brings to both the lead industry and to the battery manufacturers are covered. Topics include the lead market (its size and structure), the economic constraints on the recycling system, recycling rates for batteries, the technology of recycling, and future considerations.

Pugh, A. (Britannia Refined Metals, Northfleet (United Kingdom))

1993-05-01

38

Agglomerative percolation in two dimensions  

Microsoft Academic Search

We study a process termed agglomerative percolation (AP) in two dimensions. Instead of adding sites or bonds at random, in AP randomly chosen clusters are linked to all their neighbors. As a result the growth process involves a diverging length scale near a critical point. Picking target clusters with probability proportional to their mass leads to a runaway compact cluster.

C. Christensen; G. Bizhani; S.-W. Son; M. Paczuski; P. Grassberger

2012-01-01

39

Elastic Properties of Random Percolating Systems  

Microsoft Academic Search

We study the macroscopic elastic moduli of an elastic percolating network in the critical region. A microscopic elastic Hamiltonian is used, which contains a bending energy term. We find that the rigidity threshold of this system is identical to the percolation threshold pc. By considering the elastic properties of elements of the infinite percolation cluster we calculate the critical exponent

Yacov Kantor; Itzhak Webman

1984-01-01

40

Linear algebra and bootstrap percolation  

Microsoft Academic Search

In $\\\\HH$-bootstrap percolation, a set $A \\\\subset [n]$ of initially `infected' vertices spreads by infecting vertices which are the only uninfected vertex in an edge of the hypergraph $\\\\HH \\\\subset \\\\P(n)$. A particular case of this is the $H$-bootstrap process, in which $\\\\HH$ encodes copies of $H$ in a graph $G$. We find the minimum size of a set $A$

József Balogh; Béla Bollobás; Robert Morris; Oliver Riordan

2011-01-01

41

Long Range Percolation Mixing Time  

E-print Network

We provide an estimate, sharp up to poly-logarithmic factors, of the asymptotically almost sure mixing time of the graph created by long-range percolation on the cycle of length N (Z/NZ). While it is known that the almost sure diameter drops from linear to poly-logarithmic as the exponent s decreases below 2, the almost sure mixing time drops from N^2 only to N^(s-1) (up to poly-logarithmic factors).

Itai Benjamini; Noam Berger; Ariel Yadin

2007-03-29

42

Percolation in dense storage arrays  

NASA Astrophysics Data System (ADS)

As computers and their accessories become smaller, cheaper, and faster the providers of news, retail sales, and other services we now take for granted on the Internet have met their increasing computing needs by putting more and more computers, hard disks, power supplies, and the data communications linking them to each other and to the rest of the wired world into ever smaller spaces. This has created a new and quite interesting percolation problem. It is no longer desirable to fix computers, storage or switchgear which fail in such a dense array. Attempts to repair things are all too likely to make problems worse. The alternative approach, letting units “fail in place”, be removed from service and routed around, means that a data communications environment will evolve with an underlying regular structure but a very high density of missing pieces. Some of the properties of this kind of network can be described within the existing paradigm of site or bond percolation on lattices, but other important questions have not been explored. I will discuss 3D arrays of hundreds to thousands of storage servers (something which it is quite feasible to build in the next few years), and show that bandwidth, but not percolation fraction or shortest path lengths, is the critical factor affected by the “fail in place” disorder. Redundancy strategies traditionally employed in storage systems may have to be revised. Novel approaches to routing information among the servers have been developed to minimize the impact.

Kirkpatrick, Scott; Wilcke, Winfried W.; Garner, Robert B.; Huels, Harald

2002-11-01

43

RECYCLING TODAY  

NSDL National Science Digital Library

We have probably heard of recycling but what is it really and why is it so improtant to do? Please answer the questions below as well as visiting the different websites to explore what recycling really is. Form groups of 4 and explore the following websites as well as answer the questions which follow. The first website is of Recycle City where you will be exploring the City and how they recycle. Recyle City Why Recycling is Important Now please answer the following questions on paper. 1. What are the 3 R's? Explain in further ...

Smith, Miss

2010-12-03

44

"Explosive Percolation" Transition is Actually Continuous  

E-print Network

The basic notion of percolation in physics assumes the emergence of a giant connected (percolation) cluster in a large disordered system when the density of connections exceeds some critical value. Until recently, the percolation phase transitions were believed to be continuous, however, in 2009, a remarkably different, discontinuous phase transition was reported in a new so-called "explosive percolation" problem. Each link in this problem is established by a specific optimization process. Here, employing strict analytical arguments and numerical calculations, we find that in fact the "explosive percolation" transition is continuous though with an uniquely small critical exponent of the percolation cluster size. These transitions provide a new class of critical phenomena in irreversible systems and processes.

R. A. da Costa; S. N. Dorogovtsev; A. V. Goltsev; J. F. F. Mendes

2010-09-13

45

Percolation-induced frost formation  

NASA Astrophysics Data System (ADS)

We report the observation of an unconventional mechanism for frost formation. On a smooth hydrophobic surface cooled much below the water freezing temperature (-9 °C), we find that, instead of the classical freezing of individual supercooled condensed droplets, frost can occur through a multi-step 2-dimensional percolation-driven mechanism. This in-plane propagation process provides a model to investigate more complex bulk phase transformations such as those occurring in atmospheric supercooled clouds. It can also lead to a new method to control and design in-plane solidification at a nanoscale level.

Guadarrama-Cetina, J.; Mongruel, A.; González-Viñas, W.; Beysens, D.

2013-01-01

46

Directed polymers versus directed percolation  

NASA Astrophysics Data System (ADS)

Universality plays a central role within the rubric of modern statistical mechanics, wherein an insightful continuum formulation rises above irrelevant microscopic details, capturing essential scaling behaviors. Nevertheless, occasions do arise where the lattice or another discrete aspect can constitute a formidable legacy. Directed polymers in random media, along with its close sibling, directed percolation, provide an intriguing case in point. Indeed, the deep blood relation between these two models may have sabotaged past efforts to fully characterize the Kardar-Parisi-Zhang universality class, to which the directed polymer belongs.

Halpin-Healy, Timothy

1998-10-01

47

Fusion algebra of critical percolation  

E-print Network

We present an explicit conjecture for the chiral fusion algebra of critical percolation considering Virasoro representations with no enlarged or extended symmetry algebra. The representations we take to generate fusion are countably infinite in number. The ensuing fusion rules are quasi-rational in the sense that the fusion of a finite number of these representations decomposes into a finite direct sum of these representations. The fusion rules are commutative, associative and exhibit an sl(2) structure. They involve representations which we call Kac representations of which some are reducible yet indecomposable representations of rank 1. In particular, the identity of the fusion algebra is a reducible yet indecomposable Kac representation of rank 1. We make detailed comparisons of our fusion rules with the recent results of Eberle-Flohr and Read-Saleur. Notably, in agreement with Eberle-Flohr, we find the appearance of indecomposable representations of rank 3. Our fusion rules are supported by extensive numerical studies of an integrable lattice model of critical percolation. Details of our lattice findings and numerical results will be presented elsewhere.

Jorgen Rasmussen; Paul A. Pearce

2007-06-19

48

Hamiltonian approach for explosive percolation  

NASA Astrophysics Data System (ADS)

We present a cluster growth process that provides a clear connection between equilibrium statistical mechanics and an explosive percolation model similar to the one recently proposed by D. Achlioptas [Science 323, 1453 (2009)]. We show that the following two ingredients are sufficient for obtaining an abrupt (first-order) transition in the fraction of the system occupied by the largest cluster: (i) the size of all growing clusters should be kept approximately the same, and (ii) the inclusion of merging bonds (i.e., bonds connecting vertices in different clusters) should dominate with respect to the redundant bonds (i.e., bonds connecting vertices in the same cluster). Moreover, in the extreme limit where only merging bonds are present, a complete enumeration scheme based on treelike graphs can be used to obtain an exact solution of our model that displays a first-order transition. Finally, the presented mechanism can be viewed as a generalization of standard percolation that discloses a family of models with potential application in growth and fragmentation processes of real network systems.

Moreira, A. A.; Oliveira, E. A.; Reis, S. D. S.; Herrmann, H. J.; Andrade, J. S., Jr.

2010-04-01

49

IC.1RUS 31, 348-355 (1977) The Distribution of Ammonia and Its Photochemical  

E-print Network

chemical scheme, and rate constants. Realistic limits are placed on the concen- tration of hydrazine which may participate in the recycling of ammonia on Jupiter. The maximum hydrazine ice production rate supersaturation of hydrazine. The nitrogen mixing ratio near the ammonia cloud top is estimated to be in the range

Atreya, Sushil

50

Free percolation and seepage flows from watercourses  

Microsoft Academic Search

Free percolation and seepage flows from natural and artificial watercourses with curvilinear profiles are considered. The rigorous hydrodynamic solution of the problem of free percolation and seepage flow from a watercourse is obtained by representing the watercourse profiles in the plane of the Joukowski variable by means of the equation of a family of lemniscates and using the conformal mapping

K. N. Anakhaev

2004-01-01

51

Percolation model with continuously varying exponents  

NASA Astrophysics Data System (ADS)

This work analyzes a percolation model on the diamond hierarchical lattice (DHL), where the percolation transition is retarded by the inclusion of a probability of erasing specific connected structures. It has been inspired by the recent interest on the existence of other universality classes of percolation models. The exact scale invariance and renormalization properties of DHL leads to recurrence maps, from which analytical expressions for the critical exponents and precise numerical results in the limit of very large lattices can be derived. The critical exponents ? and ? of the investigated model vary continuously as the erasing probability changes. An adequate choice of the erasing probability leads to the result ?=?, like in some phase transitions involving vortex formation. The percolation transition is continuous, with ?>0, but ? can be as small as desired. The modified percolation model turns out to be equivalent to the Q?1 limit of a Potts model with specific long range interactions on the same lattice.

Andrade, R. F. S.; Herrmann, H. J.

2013-10-01

52

Recycling batteries  

Microsoft Academic Search

Hundreds of millions of large and billions of small batteries are used up annually in the service of all manner of electronic devices. Until recently, the tons of toxic materials in these batteries would wind up in the garbage, but the systematic collection and recycling of spent batteries is growing. Effective recycling involves changes at all stages of battery life,

F. C. McMichael; C. Henderson

1998-01-01

53

Sources of atmospheric ammonia  

NASA Technical Reports Server (NTRS)

The information available on factors that influence emissions from the principal societal sources of ammonia to the atmosphere, namely combustion processes, volatilization of farm animal wastes, and volatilization of fertilizers, is reviewed. Emission factors are established for each major source of atmospheric ammonia. The factors are then multiplied by appropriate source characterization descriptors to obtain calculated fluxes of ammonia to the atmosphere on a state-by-state basis for the United States.

Harriss, R. C.; Michaels, J. T.

1982-01-01

54

Percolation on Dependent Antagonistic Networks  

E-print Network

Percolation analysis on interdependent networks has shown the existence of first order phase transitions. In this article we show that for a system consisting of antagonistic and dependent interactions between two networks, the phase transition is continuous. By antagonistic dependent interactions, we mean that a proportion of functional nodes in a network cause failure of nodes in the other, while failure of nodes in the other results in failure of links in the first. Surprisingly, we observe a region in the parameter space where the giant connected components of both networks start oscillating, whereas outside this region both networks are stable. For Erdos-Renyi and scale free networks this happens only when the dependency and antagonism between them is very high.

Kotnis, Bhushan

2014-01-01

55

Bootstrap percolation on spatial networks  

E-print Network

We numerically study bootstrap percolation on Kleinberg's spatial networks, in which the probability density function of a node to have a long-range link at distance $r$ scales as $P(r)\\sim r^{\\alpha}$. Setting the ratio of the size of the giant active component to the network size as the order parameter, we find a critical exponent $\\alpha_{c}=-1$, above which a hybrid phase transition is observed, with both the first-order and second-order critical points being constant. When $\\alpha<\\alpha_{c}$, the second-order critical point increases as the decreasing of $\\alpha$, and there is either absent of the first-order phase transition or with a decreasing first-order critical point as the decreasing of $\\alpha$, depending on other parameters. Our results expand the current understanding on the spreading of information and the adoption of behaviors on spatial social networks.

Gao, Jian; Hu, Yanqing

2014-01-01

56

Transport on exploding percolation clusters.  

PubMed

We propose a simple generalization of the explosive percolation process [Achlioptas et al., Science 323, 1453 (2009)], and investigate its structural and transport properties. In this model, at each step, a set of q unoccupied bonds is randomly chosen. Each of these bonds is then associated with a weight given by the product of the cluster sizes that they would potentially connect, and only that bond among the q set which has the smallest weight becomes occupied. Our results indicate that, at criticality, all finite-size scaling exponents for the spanning cluster, the conducting backbone, the cutting bonds, and the global conductance of the system, change continuously and significantly with q. Surprisingly, we also observe that systems with intermediate values of q display the worst conductive performance. This is explained by the strong inhibition of loops in the spanning cluster, resulting in a substantially smaller associated conducting backbone. PMID:21517480

Andrade, José S; Herrmann, Hans J; Moreira, André A; Oliveira, Cláudio L N

2011-03-01

57

Assessing Ammonia Treatment Options  

EPA Science Inventory

This is the second of three articles to help water system operators understand ammonia and how to monitor and control its effects at the plant and in the distribution system. The first article (Opflow, April 2012) provided an overview of ammonia's chemistry, origins, and water sy...

58

Negative-weight percolation O. Melchert, A.K. Hartmann  

E-print Network

, geometric transition Characterize loops using observables from percolation theory (finite-size scaling (FSS) analysis) 5 / 10 #12;Percolation probability Percolation proba- bility exhibits FSS: Ps L f[(-c)L1/ ] c scaling for mean number of spanning loops 6 / 10 #12;Percolation strength Exhibits FSS: P L L-/ f[(-c)L1

Peinke, Joachim

59

Extreme Recycling  

E-print Network

Broadcast Transcript: Singing the recycling blues because you have to separate your chipboard from your newspaper, your steel from your aluminum, your #1 from your #2 plastic? Pantywaists! The residents of Kamikatsu, Japan have no fewer than 34...

Hacker, Randi

2009-01-14

60

Ideas: Recycling.  

ERIC Educational Resources Information Center

Presents classroom ideas focusing on connections among mathematics, concern for the environment, and conservation of natural resources, including decomposition, water conservation, packaging materials, use of manufactured cans, and recycling. Includes reproducible student worksheets. (MKR)

Chessin, Debby A.; And Others

1994-01-01

61

Recycle City  

NSDL National Science Digital Library

Recycling made fun. The Environmental Protection Agency's Recycle City Web site offers students an interactive way to learn how recycling can affect their environment. Users can click any part of the cartoon drawing of the city to learn about that particular building or site and what can be done to decrease waste. The site also contains a more involved exercise called the Dumptown game, where visitors click on City Hall to view various recycling programs and choose the program(s) the city will implement. Once implemented, that activity can be seen taking place in Dumptown. Although the Dumptown exercise may require the help of a teacher to navigate for younger students, both exercises are excellent for K-12 teachers and students.

1997-01-01

62

Percolation model of relative permeability hysteresis  

NASA Astrophysics Data System (ADS)

A mathematical model of relative permeability hysteresis in drainage and imbibition is constructed on the basis of percolation theory. It is shown that the results are in qualitatively agreement with experimental data.

Kadet, V. V.; Galechyan, A. M.

2013-05-01

63

Continuum Percolation in the Relative Neighborhood Graph  

E-print Network

In the present study, we establish the existence of nontrivial site percolation threshold in the Relative Neighborhood Graph (RNG) for Poisson stationary point process with unit intensity in the plane.

Jean-Michel Billiot; Franck Corset; Eric Fontenas

2010-04-29

64

Continuum percolation thresholds in two dimensions  

NASA Astrophysics Data System (ADS)

A wide variety of methods have been used to compute percolation thresholds. In lattice percolation, the most powerful of these methods consists of microcanonical simulations using the union-find algorithm to efficiently determine the connected clusters, and (in two dimensions) using exact values from conformal field theory for the probability, at the phase transition, that various kinds of wrapping clusters exist on the torus. We apply this approach to percolation in continuum models, finding overlaps between objects with real-valued positions and orientations. In particular, we find precise values of the percolation transition for disks, squares, rotated squares, and rotated sticks in two dimensions and confirm that these transitions behave as conformal field theory predicts. The running time and memory use of our algorithm are essentially linear as a function of the number of objects at criticality.

Mertens, Stephan; Moore, Cristopher

2012-12-01

65

Connectivity percolation in suspensions of hard platelets  

E-print Network

We present a study on connectivity percolation in suspensions of hard platelets by means of Monte Carlo simulation. We interpret our results using a contact-volume argument based on an effective single--particle cell model. It is commonly assumed that the percolation threshold of anisotropic objects scales as their inverse aspect ratio. While this rule has been shown to hold for rod-like particles, we find that for hard plate-like particles the percolation threshold is non-monotonic in the aspect ratio. It exhibits a shallow minimum at intermediate aspect ratios and then saturates to a constant value. This effect is caused by the isotropic-nematic transition pre-empting the percolation transition. Hence the common strategy to use highly anisotropic, conductive particles as fillers in composite materials in order to produce conduction at low filler concentration is expected to fail for plate-like fillers such as graphene and graphite nanoplatelets.

Maneesh Mathew; Tanja Schilling; Martin Oettel

2012-04-13

66

Percolation of secret correlations in a network  

E-print Network

In this work, we explore the analogy between entanglement and secret classical correlations in the context of large networks—more precisely, the question of percolation of secret correlations in a network. It is known that ...

Raul, Garcia-Patron

67

DIPLOMA THESIS Conformal invariance of critical percolation  

E-print Network

of percolation on planar graphs is developed enough to verify conjectures of statistical phisical flavour. We can. The fruitful idea of identifying the plane with the set of complex numbers £ is of statistical phisical origin

Ráth, Balázs

68

Virtual Bond Percolation for Ising Cluster Dynamics  

E-print Network

The Fortuin-Kasteleyn mapping between the Ising model and the site-bond correlated percolation model is shown to be only one of an infinite class of exact mappings. These new cluster representations are a result of "renormalized" percolation rules correlated to entire blocks of spins. For example these rules allow for percolation on "virtual" bonds between spins not present in the underlying Hamiltonian. As a consequence we can define new random cluster theories each with its own Monte Carlo cluster dynamics that exactly reproduce the Ising model. By tuning parameters on the critical percolation surface, it is demonstrated numerically that cluster algorithms can be formulated for the 2-d and 3-d Ising model that have smaller autocorrelations than the original Swendsen-Wang algorithm.

R. Brower; P. Tamayo

1992-06-04

69

Percolation on networks with dependence links  

NASA Astrophysics Data System (ADS)

As a classical model of statistical physics, the percolation theory provides a powerful approach to analyze the network structure and dynamics. Recently, to model the relations among interacting agents beyond the connection of the networked system, the concept of dependence link is proposed to represent the dependence relationship of agents. These studies suggest that the percolation properties of these networks differ greatly from those of the ordinary networks. In particular, unlike the well known continuous transition on the ordinary networks, the percolation transitions on these networks are discontinuous. Moreover, these networks are more fragile for a broader degree distribution, which is opposite to the famous results for the ordinary networks. In this article, we give a summary of the theoretical approaches to study the percolation process on networks with inter- and inner-dependence links, and review the recent advances in this field, focusing on the topology and robustness of such networks.

Li, Ming; Wang, Bing-Hong

2014-07-01

70

Inducing effect on the percolation transition in complex networks  

NASA Astrophysics Data System (ADS)

Percolation theory concerns the emergence of connected clusters that percolate through a networked system. Previous studies ignored the effect that a node outside the percolating cluster may actively induce its inside neighbours to exit the percolating cluster. Here we study this inducing effect on the classical site percolation and K-core percolation, showing that the inducing effect always causes a discontinuous percolation transition. We precisely predict the percolation threshold and core size for uncorrelated random networks with arbitrary degree distributions. For low-dimensional lattices the percolation threshold fluctuates considerably over realizations, yet we can still predict the core size once the percolation occurs. The core sizes of real-world networks can also be well predicted using degree distribution as the only input. Our work therefore provides a theoretical framework for quantitatively understanding discontinuous breakdown phenomena in various complex systems.

Zhao, Jin-Hua; Zhou, Hai-Jun; Liu, Yang-Yu

2013-09-01

71

Percolation of secret correlations in a network  

SciTech Connect

In this work, we explore the analogy between entanglement and secret classical correlations in the context of large networks--more precisely, the question of percolation of secret correlations in a network. It is known that entanglement percolation in quantum networks can display a highly nontrivial behavior depending on the topology of the network and on the presence of entanglement between the nodes. Here we show that this behavior, thought to be of a genuine quantum nature, also occurs in a classical context.

Leverrier, Anthony; Garcia-Patron, Raul [ICFO-Institut de Ciencies Fotoniques, 08860 Castelldefels (Barcelona) (Spain); Research Laboratory of Electronics, MIT, Cambridge, MA 02139 (United States) and Max-Planck Institut fur Quantenoptik, Hans-Kopfermann Str. 1, D-85748 Garching (Germany)

2011-09-15

72

Percolation of secret correlations in a network  

E-print Network

In this work, we explore the analogy between entanglement and secret classical correlations in the context of large networks, more precisely the question of percolation of secret correlations in a network. It is known that entanglement percolation in quantum networks can display a highly nontrivial behavior depending on the topology of the network and on the presence of entanglement between the nodes. Here we show that this behavior, thought to be of a genuine quantum nature, also occurs in a classical context.

Anthony Leverrier; Raul Garcia-Patron

2011-07-08

73

Recent advances and open challenges in percolation  

NASA Astrophysics Data System (ADS)

Percolation is the paradigm for random connectivity and has been one of the most applied statistical models. With simple geometrical rules a transition is obtained which is related to magnetic models. This transition is, in all dimensions, one of the most robust continuous transitions known. We present a very brief overview of more than 60 years of work in this area and discuss several open questions for a variety of models, including classical, explosive, invasion, bootstrap, and correlated percolation.

Araújo, N.; Grassberger, P.; Kahng, B.; Schrenk, K. J.; Ziff, R. M.

2014-10-01

74

Connecting the vulcanization transition to percolation  

NASA Astrophysics Data System (ADS)

The vulcanization transition is addressed via a minimal replica-field-theoretic model. The appropriate long-wavelength behavior of the two- and three-point vertex functions is considered diagrammatically, to all orders in perturbation theory, and identified with the corresponding quantities in the Houghton-Reeve-Wallace field-theoretic approach to the percolation critical phenomenon. Hence, it is shown that percolation theory correctly captures the critical phenomenology of the vulcanization transition associated with the liquid and critical states.

Peng, Weiqun; Goldbart, Paul M.; McKane, Alan J.

2001-09-01

75

Multiple-well invasion percolation.  

PubMed

When the invasion percolation model is applied as a simplified model for the displacement of a viscous fluid by a less viscous one, the distribution of displaced mass follows two distinct universality classes, depending on the criteria used to stop the displacement. Here we study the distribution of mass for this process, in the case where four extraction wells are placed around a single injection well in the middle of a square lattice. Our analysis considers the limit where the pressure of the extraction well Pe is zero; in other words, an extraction well is capped as soon as less viscous fluid reaches that extraction well. Our results show that, as expected, the probability of stopping the production with small amounts of displaced mass is greatly reduced. We also investigate whether or not creating extra extraction wells is an efficient strategy. We show that the probability of increasing the amount of displaced fluid by adding an extra extraction well depends on the total recovered mass obtained before adding this well. The results presented here could be relevant to determine efficient strategies in oil exploration. PMID:18517620

Araújo, A D; Romeu, M C; Moreira, A A; Andrade, R F S; Andrade, J S

2008-04-01

76

Bootstrap Percolation on Complex Networks  

E-print Network

We consider bootstrap percolation on uncorrelated complex networks. We obtain the phase diagram for this process with respect to two parameters: $f$, the fraction of vertices initially activated, and $p$, the fraction of undamaged vertices in the graph. We observe two transitions: the giant active component appears continuously at a first threshold. There may also be a second, discontinuous, hybrid transition at a higher threshold. Avalanches of activations increase in size as this second critical point is approached, finally diverging at this threshold. We describe the existence of a special critical point at which this second transition first appears. In networks with degree distributions whose second moment diverges (but whose first moment does not), we find a qualitatively different behavior. In this case the giant active component appears for any $f>0$ and $p>0$, and the discontinuous transition is absent. This means that the giant active component is robust to damage, and also is very easily activated. We also formulate a generalized bootstrap process in which each vertex can have an arbitrary threshold.

G J Baxter; S N Dorogovtsev; A V Goltsev; J F F Mendes

2010-03-29

77

General clique percolation in random networks  

NASA Astrophysics Data System (ADS)

A general (k,l) clique community of a network, which consists of adjacent k-cliques sharing at least l vertices with k-1\\ge l\\ge1 , is introduced. With the emergence of a giant (k,l) clique community in the network, there is a (k,l) clique percolation. Using the largest size jump ? of the largest clique community during network evolution and the corresponding evolution step Tc, we study the general (k,l) clique percolation of the Erd?s-Rényi network. We investigate the averages of ? and Tc and their fluctuations for different network size N. The clique percolation can be identified by the power-law finite-size effects of the averages and root mean squares of fluctuation. The finite-size scaling distribution functions of fluctuations are calculated. The universality class of the (k,l) clique percolation is characterized by the critical exponents of power-law finite-size effects. Using Monte Carlo simulations, we find that the Erd?s-Rényi network experiences a series of (k,l) clique percolation with (k,l)=(2,1),(3,1),(3,2),(4,1),(4,2),(4,3),(5,1) . We find that the critical exponents and therefore the universality class of the (k,l) clique percolation depend on clique connection index l, but are independent of clique size k.

Fan, Jingfang; Chen, Xiaosong

2014-07-01

78

Critical exponents of the explosive percolation transition  

E-print Network

In a new type of percolation phase transition, which was observed in a set of non-equilibrium models, each new connection between vertices is chosen from a number of possibilities by an Achlioptas-like algorithm. This causes preferential merging of small components and delays the emergence of the percolation cluster. First simulations led to a conclusion that a percolation cluster in this irreversible process is born discontinuously, by a discontinuous phase transition, which results in the term "explosive percolation transition". We have shown that this transition is actually continuous (second-order) though with an anomalously small critical exponent of the percolation cluster. Here we propose an efficient numerical method enabling us to find the critical exponents and other characteristics of this second order transition for a representative set of explosive percolation models with different number of choices. The method is based on gluing together the numerical solutions of evolution equations for the cluster size distribution and power-law asymptotics. For each of the models, with high precision, we obtain critical exponents and the critical point.

R. A. da Costa; S. N. Dorogovtsev; A. V. Goltsev; J. F. F. Mendes

2014-02-18

79

Molecular Structure of Ammonia  

NSDL National Science Digital Library

Ammonia is a non-ionic colorless gas at ambient temperatures and a hydrogen bonding liquid at 240 Kelvin that has the remarkable ability to dissolve alkali metals. Ammonia is a Lewis base and is readily absorbed by water to form small amounts of ammonium hydroxide (pKb = 4.74). Naturally, ammonia has its sources in the biosphere (the nitrogen cycle) and is a trace gas in air and a source of ammonium ions in rain and atmospheric aerosols. Ammonia is prepared industrially by the Haber-Bosch process in quantities exceeding 120 million metric tons per year. In this process, ammonia gas is formed when hydrogen and nitrogen (3:1) are compressed to pressures of 200 atm and passed over an iron catalyst at 380-450 degrees C. Much of the ammonia produced this way (85%) is used as fertilizers on crops, a significant portion of which leaches from croplands into streams causing nitrate pollution and eutrophication of waterways (e.g., dead-zone in the Gulf of Mexico). Other sources of ammonia include combustion (coal and biomass burning) and from bacterial decomposition of animal excreta.

2006-05-02

80

Ammonia Leak Locator Study  

NASA Technical Reports Server (NTRS)

The thermal control system of International Space Station Alpha will use liquid ammonia as the heat exchange fluid. It is expected that small leaks (of the order perhaps of one pound of ammonia per day) may develop in the lines transporting the ammonia to the various facilities as well as in the heat exchange equipment. Such leaks must be detected and located before the supply of ammonia becomes critically low. For that reason, NASA-JSC has a program underway to evaluate instruments that can detect and locate ultra-small concentrations of ammonia in a high vacuum environment. To be useful, the instrument must be portable and small enough that an astronaut can easily handle it during extravehicular activity. An additional complication in the design of the instrument is that the environment immediately surrounding ISSA will contain small concentrations of many other gases from venting of onboard experiments as well as from other kinds of leaks. These other vapors include water, cabin air, CO2, CO, argon, N2, and ethylene glycol. Altogether, this local environment might have a pressure of the order of 10(exp -7) to 10(exp -6) torr. Southwest Research Institute (SwRI) was contracted by NASA-JSC to provide support to NASA-JSC and its prime contractors in evaluating ammonia-location instruments and to make a preliminary trade study of the advantages and limitations of potential instruments. The present effort builds upon an earlier SwRI study to evaluate ammonia leak detection instruments [Jolly and Deffenbaugh]. The objectives of the present effort include: (1) Estimate the characteristics of representative ammonia leaks; (2) Evaluate the baseline instrument in the light of the estimated ammonia leak characteristics; (3) Propose alternative instrument concepts; and (4) Conduct a trade study of the proposed alternative concepts and recommend promising instruments. The baseline leak-location instrument selected by NASA-JSC was an ion gauge.

Dodge, Franklin T.; Wuest, Martin P.; Deffenbaugh, Danny M.

1995-01-01

81

Textile recycling  

SciTech Connect

The most common household textiles include clothing, linens, draperies, carpets, shoes, handbags, and rugs. Old clothing, of course, is the most readily reused and/or recycled residentially generated textile category. State and/or local mandates to recycle a percentage of the waste stream are providing the impetus to add new materials to existing collection programs. Concurrently, the textile industry is aggressively trying to increase its throughput by seeking new sources of material to meet increased world demand for product. As experienced with drop-off programs for traditional materials, a majority of residents will not recycle materials unless the collection programs are convenient, i.e., curbside collection. The tonnage of marketable textiles currently being landfilled provide evidence of this. It is the authors' contention that if textile recycling is made convenient and accessible to every household in a municipality or region, then the waste stream disposed may be reduced in a similar fashion as when traditional recyclables are included in curbside programs.

Jablonowski, E. (Killam Associates, Millburn, NJ (United States)); Carlton, J.

1995-01-01

82

SOURCE ASSESSMENT: SYNTHETIC AMMONIA PRODUCTION  

EPA Science Inventory

The report describes a study of air emissions from the production of synthetic ammonia. In 1976, 90 synthetic ammonia plants in 30 states produced 15.2 million metric tons of anhydrous ammonia. Ammonia is synthesized by the reaction of nitrogen and hydrogen. Most plants produce h...

83

Application of percolation theory to microtomography of structured media: percolation threshold, critical exponents, and upscaling.  

PubMed

Percolation theory provides a tool for linking microstructure and macroscopic material properties. In this paper, percolation theory is applied to the analysis of microtomographic images for the purpose of deriving scaling laws for upscaling of properties. We have tested the acquisition of quantities such as percolation threshold, crossover length, fractal dimension, and critical exponent of correlation length from microtomography. By inflating or deflating the target phase and percolation analysis, we can get a critical model and an estimation of the percolation threshold. The crossover length is determined from the critical model by numerical simulation. The fractal dimension can be obtained either from the critical model or from the relative size distribution of clusters. Local probabilities of percolation are used to extract the critical exponent of the correlation length. For near-isotropic samples such as sandstone and bread, the approach works very well. For strongly anisotropic samples, such as highly deformed rock (mylonite) and a tree branch, the percolation threshold and fractal dimension can be assessed with accuracy. However, the uncertainty of the correlation length makes it difficult to accurately extract its critical exponents. Therefore, this aspect of percolation theory cannot be reliably used for upscaling properties of strongly anisotropic media. Other methods of upscaling have to be used for such media. PMID:21405743

Liu, Jie; Regenauer-Lieb, Klaus

2011-01-01

84

Utility of Recycled Bedding for Laboratory Rodents  

PubMed Central

Animal facilities generate a large amount of used bedding containing excrement as medical waste. We developed a recycling system for used bedding that involves soft hydrothermal processing. In this study, we examined the effects of bedding type on growth, hematologic and serum biochemical values, and organ weights of female and male mice reared on either recycled or fresh bedding from 3 to 33 wk of age. Neither growth nor physiology differed between mice housed on recycled bedding compared with fresh bedding. When 14-wk-old mice were bred, litter size and total number of weaned pups showed no significant differences between animals raised on recycled or fresh bedding. Because bedding type influences the environment within cages and animal rooms, we evaluated particulate and ammonia data from cages and animal rooms. Values were significantly lower from cages and rooms that used recycled bedding than from those using fresh bedding, thus indicating that recycled bedding has the potential to improve the environment within both cages and animal rooms. Overall, this study revealed that recycled bedding is an excellent material for use in housing laboratory rodents. Specifically, recycled bedding may reduce medical waste and maintain healthy environments within cages and animal rooms. PMID:19653951

Miyamoto, Toru; Li, Zhixia; Kibushi, Tomomi; Okano, Shinya; Yamasaki, Nakamichi; Kasai, Noriyuki

2009-01-01

85

Percolation Centrality: Quantifying Graph-Theoretic Impact of Nodes during Percolation in Networks  

PubMed Central

A number of centrality measures are available to determine the relative importance of a node in a complex network, and betweenness is prominent among them. However, the existing centrality measures are not adequate in network percolation scenarios (such as during infection transmission in a social network of individuals, spreading of computer viruses on computer networks, or transmission of disease over a network of towns) because they do not account for the changing percolation states of individual nodes. We propose a new measure, percolation centrality, that quantifies relative impact of nodes based on their topological connectivity, as well as their percolation states. The measure can be extended to include random walk based definitions, and its computational complexity is shown to be of the same order as that of betweenness centrality. We demonstrate the usage of percolation centrality by applying it to a canonical network as well as simulated and real world scale-free and random networks. PMID:23349699

Piraveenan, Mahendra; Prokopenko, Mikhail; Hossain, Liaquat

2013-01-01

86

Alternative E ammonia feedstock  

SciTech Connect

Power plants are using more Ammonia for increasing precipitator and baghouse efficiency, for SCR and SNCR processes, and for controlling acid stack plumes and dewpoint corrosion. These simple systems inject ammonia and air into the furnace or the precipitator or baghouse inlet ductwork. The common feedstocks in use today are Anhydrous ammonia [NH{sub 3}] and Aqueous ammonia [NH{sub 4}OH], both defined as poison gases by US authorities and most Western nations. Storage and handling procedures for these products are strictly regulated. Wilhelm Environmental Technologies Inc. is developing use of solid, formed or prilled Urea [CO(NH{sub 2}){sub 2}] as the feedstock. When heated in moist air, Urea sublimes to ammonia [NH{sub 3}] and carbon dioxide [CO{sub 2}]. Urea is stored and handled without restrictions or environmental concerns. Urea is a more expensive feedstock than NH{sub 3}, but much less expensive than [NH{sub 4}OH]. The design, and operating results, of a pilot system at Jacksonville Electric St. John's River Plant [Unit 2] are described. The pilot plant successfully sublimed Urea up to 100 pounds/hour. Further testing is planned. Very large ammonia use may favor NH{sub 3}, but smaller quantities can be produced at attractive prices with Urea based ammonia systems. Storage costs are far less. Many fluidized-bed boilers can use pastille or solid urea metered directly into the existing cyclones for NO{sub x} control. This is more economical than aqueous ammonia or aqueous urea based technology.

Lentz, M.J.; Wright, R.A. [Wilhelm Environmental Technologies, Indianapolis, IN (US)

1999-07-01

87

Potts and percolation models on bowtie lattices  

NASA Astrophysics Data System (ADS)

We give the exact critical frontier of the Potts model on bowtie lattices. For the case of q=1, the critical frontier yields the thresholds of bond percolation on these lattices, which are exactly consistent with the results given by Ziff [J. Phys. A0305-447010.1088/0305-4470/39/49/003 39, 15083 (2006)]. For the q=2 Potts model on a bowtie A lattice, the critical point is in agreement with that of the Ising model on this lattice, which has been exactly solved. Furthermore, we do extensive Monte Carlo simulations of the Potts model on a bowtie A lattice with noninteger q. Our numerical results, which are accurate up to seven significant digits, are consistent with the theoretical predictions. We also simulate the site percolation on a bowtie A lattice, and the threshold is sc=0.5479148(7). In the simulations of bond percolation and site percolation, we find that the shape-dependent properties of the percolation model on a bowtie A lattice are somewhat different from those of an isotropic lattice, which may be caused by the anisotropy of the lattice.

Ding, Chengxiang; Wang, Yancheng; Li, Yang

2012-08-01

88

Endocytic recycling  

Microsoft Academic Search

After endocytosis, most membrane proteins and lipids return to the cell surface, but some membrane components are delivered to late endosomes or the Golgi. We now understand that the pathways taken by internalized molecules that eventually recycle to the cell surface can be surprisingly complex and can involve a series of sorting events that occur in several organelles. The molecular

Frederick R. Maxfield; Timothy E. McGraw

2004-01-01

89

Weakly explosive percolation in directed networks  

NASA Astrophysics Data System (ADS)

Percolation, the formation of a macroscopic connected component, is a key feature in the description of complex networks. The dynamical properties of a variety of systems can be understood in terms of percolation, including the robustness of power grids and information networks, the spreading of epidemics and forest fires, and the stability of gene regulatory networks. Recent studies have shown that if network edges are added “competitively” in undirected networks, the onset of percolation is abrupt or “explosive.” The unusual qualitative features of this phase transition have been the subject of much recent attention. Here we generalize this previously studied network growth process from undirected networks to directed networks and use finite-size scaling theory to find several scaling exponents. We find that this process is also characterized by a very rapid growth in the giant component, but that this growth is not as sudden as in undirected networks.

Squires, Shane; Sytwu, Katherine; Alcala, Diego; Antonsen, Thomas M.; Ott, Edward; Girvan, Michelle

2013-05-01

90

Discrete time quantum walks on percolation graphs  

E-print Network

Randomly breaking connections in a graph alters its transport properties, a model used to describe percolation. In the case of quantum walks, dynamic percolation graphs represent a special type of imperfections, where the connections appear and disappear randomly in each step during the time evolution. The resulting open system dynamics is hard to treat numerically in general. We shortly review the literature on this problem. We then present our method to solve the evolution on finite percolation graphs in the long time limit, applying the asymptotic methods concerning random unitary maps. We work out the case of one dimensional chains in detail and provide a concrete, step by step numerical example in order to give more insight into the possible asymptotic behavior. The results about the case of the two-dimensional integer lattice are summarized, focusing on the Grover type coin operator.

Bálint Kollár; Jaroslav Novotný; Tamás Kiss; Igor Jex

2014-04-17

91

Solution of the explosive percolation quest  

E-print Network

Percolation refers to the emergence of a giant connected cluster in a disordered system when the number of connections between nodes exceeds a critical value. The percolation phase transitions were believed to be continuous until recently when in a new so-called "explosive percolation" problem for a competition driven process, a discontinuous phase transition was reported. The analysis of evolution equations for this process showed however that this transition is actually continuous though with surprisingly tiny critical exponents. For a wide class of representative models, we develop a strict scaling theory of this exotic transition which provides the full set of scaling functions and critical exponents. This theory indicates the relevant order parameter and susceptibility for the problem, and explains the continuous nature of this transition and its unusual properties.

R. A. da Costa; S. N. Dorogovtsev; A. V. Goltsev; J. F. F. Mendes

2014-05-05

92

Estimation of the percolation thresholds in dextromethorphan hydrobromide matrices.  

PubMed

Percolation theory is a multidisciplinary theory that studies chaotic systems. It has been applied in the pharmaceutical field since 1987. Knowledge of the percolation threshold -- one of the most important concepts in percolation theory -- results in a clear improvement of the solid dosage form design. The percolation threshold is the concentration showing the maximum probability to obtain, for the first time, a percolating cluster of a substance. In this work, the percolation thresholds of dextromethorphan.HBr/Eudragit RS-PM inert matrices were estimated. The drug percolation threshold was estimated as 0.3691+/-0.0541 (P=0.05) of the total porosity (ranging between 23 and 36% w/w of drug). The SEM micrographs of the matrices are consistent with the estimated percolation range. In agreement with previous reports, different percolation thresholds were found for the matrix forming excipient Eudragit RS-PM. The site percolation threshold (based on the release properties) ranged between 10 and 20% v/v of the excipient, the site-bond percolation threshold (estimated from the mechanical properties) between 29.5 and 34% v/v of the excipient and the swelling percolation threshold between 34.3 and 46.9% v/v of the excipient. These percolation ranges are in agreement with those found previously for Eudragit RS-PM matrices containing naltrexone.HCl and morphine.HCl. PMID:11231112

Melgoza, L M; Rabasco, A M; Sandoval, H; Caraballo, I

2001-02-01

93

Percolation concepts in solid state ionics  

NASA Astrophysics Data System (ADS)

Structural disorder is an inherent property of solid materials, which can support a macroscopic ionic current. Many transport phenomena in these solid ionic conductors appear to be related to concepts from percolation theory. We demonstrate this for three classes of materials, namely (i) dispersed ionic conductors, which show conductance properties that can be related to random electrical networks, (ii) ion-doped network glasses, whose concentration-dependent diffusion properties are accessible by critical path analysis, and (iii) polymer ionic conductors. For the latter we discuss Monte Carlo simulations which indicate the applicability of dynamic bond percolation theory.

Dieterich, W.; Dürr, O.; Pendzig, P.; Bunde, A.; Nitzan, A.

94

Steel Recycling Institute (SRI)  

NSDL National Science Digital Library

The Steel Recycling Institute (SRI) provides information and statistics on steel recycling; it was founded by a group of steel companies and the American Iron and Steel Institute (AISI). Originally a grassroots effort focused only on the recycling of steel cans, the SRI now promotes the recycling of all steel products. The SRI homepage provides online access to its three publications, The Dockside Recycler, The Recycling Magnet, and The Appliance Recycler. Recycling information is divided into four categories: cans, cars, appliances, and construction material. Users can use the recycling database to find the nearest steel recycling location. Links provides a large list of both commercial and non-commercial steel sites.

1998-01-01

95

Precipitation Recycling  

NASA Technical Reports Server (NTRS)

The water cycle regulates and reflects natural variability in climate at the regional and global scales. Large-scale human activities that involve changes in land cover, such as tropical deforestation, are likely to modify climate through changes in the water cycle. In order to understand, and hopefully be able to predict, the extent of these potential global and regional changes, we need first to understand how the water cycle works. In the past, most of the research in hydrology focused on the land branch of the water cycle, with little attention given to the atmospheric branch. The study of precipitation recycling which is defined as the contribution of local evaporation to local precipitation, aims at understanding hydrologic processes in the atmospheric branch of the water cycle. Simply stated, any study on precipitation recycling is about how the atmospheric branch of the water cycle works, namely, what happens to water vapor molecules after they evaporate from the surface, and where will they precipitate?

Eltahir, Elfatih A. B.; Bras, Rafael L.

1996-01-01

96

Scaling and Inverse Scaling in Anisotropic Bootstrap percolation  

E-print Network

In bootstrap percolation it is known that the critical percolation threshold tends to converge slowly to zero with increasing system size, or, inversely, the critical size diverges fast when the percolation probability goes to zero. To obtain higher-order terms (that is, sharp and sharper thresholds) for the percolation threshold in general is a hard question. In the case of two-dimensional anisotropic models, sometimes correction terms can be obtained from inversion in a relatively simple manner.

Aernout C. D. van Enter

2014-05-01

97

Computer Recycling  

NSDL National Science Digital Library

Given current rates of computer consumerism and technological advances, one might expect to find a lot of computers out there in the world. What happens to these old computers? This Topic in Depth explores this issue, reviews some options for recycling computers, and provides tips for anyone considering purchasing a refurbished computer. The first article from BBC News (1) reports on research which suggests that "the number of personal computers worldwide is expected to double by 2010 to 1.3 billion machines." The second article from Oasis, a project of the Irish eGovernment initiative, (2) reviews some of the issues surrounding waste from electrical and electronic equipment. This next article from PC World (3) gives some ideas for how to dispose of an old notebook computer. One option, of course, is to donate your notebook, which is discussed in this article from Tech Soup (4). Another resource for information on computer recycling and reuse is this website from CompuMentor (5). Given the current market for computers, many are considering refurbished computers. This article from Vnunet (6 ) explains what a refurbished computer is while the next website provides some tips for buying a refurbished computer (7 ). Finally, this article from About.com reports on the recently introduced National Computer Recycling Act (8).

98

Lattice Boltzmann model for coffee percolation  

Microsoft Academic Search

A Lattice Boltzmann model is constructed for the simulation of water percolation through coffee. The model describes the dynamics of two uids (water and air) through a layer of porous medium (coffee), where the porous medium may be eroded by the o w of water. Surface tension between the uids is included, and a multi-relaxation scheme is used to improve

Luciano Misici; Silvia Palpacelli

99

Random Walks and Percolation on Trees  

Microsoft Academic Search

There is a way to define an average number of branches per vertex for an arbitrary infinite locally finite tree. It equals the exponential of the Hausdorff dimension of the boundary in an appropriate metric. Its importance for probabilistic processes on a tree is shown in several ways, including random walk and percolation, where it provides points of phase transition.

Russell Lyons

1990-01-01

100

PLANAR FIRSTPASSAGE PERCOLATION TIMES ARE NOT TIGHT  

E-print Network

with that of Newman and Piza (1993). Key words: Percolation, first passage, variance, tight, Richardson's model. 1 n. Simultaneously and independently, Newman and Piza have achieved the same result for {0, 1}­valued passage times. Their methods (Newman and Piza 1993) extend to more general passage times, while ours work

Pemantle, Robin

101

Superdiffusivity in first-passage percolation  

Microsoft Academic Search

Summary.  In standard first-passage percolation on (with ), the time-minimizing paths from a point to a plane at distance are expected to have transverse fluctuations of order . It has been conjectured that with the inequality strict (superdiffusivity) at least for low and with . We prove (versions of) for all and .

C. Licea; C. M. Newman; M. S. T. Piza

1996-01-01

102

Percolation in a fractional Brownian motion lattice  

SciTech Connect

Many applications of engineering interest involve spatially correlated properties obeying the statistics of fractional Brownian motion (fBm). Of specific interest to this note are percolation processes in a field described by fBm. There are two applications where such processes may arise: The immiscible displacement of one fluid by another in a 2-D fracture, the aperture of which obeys fBm statistics; and the same displacement in a heterogeneous porous medium, the permeability of which obeys fBm statistics. In either case, it is assumed that capillary forces dominate the displacement. In previous works, Yortsos and Chang (1990) and van Batenburg et al. (1991) simulated displacements in such fields by considering both capillary and viscous forces. Here, the authors consider the case where viscous forces are small (low flow rates). As capillary-controlled displacement is described by invasion percolation (IP), the problem of interest is one of percolation in a correlated lattice. In this note the authors present numerical results of both ordinary percolation and IP in an fBm lattice, which expand on their previous study (Satik and Yortsos, 1991) and support the findings of Isichenko (1992) and Schmittbuhl et al. (1993). The statistics of the random variables p{sub c} and P(p, H) obtained should be useful in problems involving fBm lattices. More generally, the results should be useful in the study of invasion processes in correlated media.

Du, C.; Satik, C.; Yortsos, Y.C. [Univ. of Southern California, Los Angeles, CA (United States)] [Univ. of Southern California, Los Angeles, CA (United States)

1996-08-01

103

Percolation theory and its application to groundwater hydrology  

Microsoft Academic Search

The theory of percolation, originally proposed over 30 years ago to describe flow phenomena in porous media, has undergone enormous development in recent years, primarily in the field of physics. The principal advantage of percolation theory is that it provides universal laws which determine the geometrical and physical properties of the system. This survey discusses developments and results in percolation

Brian Berkowitz; Isaac Balberg

1993-01-01

104

Site-percolation threshold of carbon nanotube fibers-Fast inspection of percolation with Markov stochastic theory  

NASA Astrophysics Data System (ADS)

We present a site-percolation model based on a modified FCC lattice, as well as an efficient algorithm of inspecting percolation which takes advantage of the Markov stochastic theory, in order to study the percolation threshold of carbon nanotube (CNT) fibers. Our Markov-chain based algorithm carries out the inspection of percolation by performing repeated sparse matrix-vector multiplications, which allows parallelized computation to accelerate the inspection for a given configuration. With this approach, we determine that the site-percolation transition of CNT fibers occurs at pc=0.1533±0.0013, and analyze the dependence of the effective percolation threshold (corresponding to 0.5 percolation probability) on the length and the aspect ratio of a CNT fiber on a finite-size-scaling basis. We also discuss the aspect ratio dependence of percolation probability with various values of p (not restricted to pc).

Xu, Fangbo; Xu, Zhiping; Yakobson, Boris I.

2014-08-01

105

Preventing Theft of Anhydrous Ammonia  

E-print Network

Anhydrous ammonia is widely used as a fertilizer. The theft of anhydrous ammonia for use in producing illegal drugs is a growing problem. This publication describes how thieves operate and how farmers and agricultural dealers can protect themselves...

Smith, David

2004-09-16

106

Combustion Byproducts Recycling Consortium  

SciTech Connect

Each year, over 100 million tons of solid byproducts are produced by coal-burning electric utilities in the United States. Annual production of flue gas desulfurization (FGD) byproducts continues to increase as the result of more stringent sulfur emission restrictions. In addition, stricter limits on NOx emissions mandated by the 1990 Clean Air Act have resulted in utility burner/boiler modifications that frequently yield higher carbon concentrations in fly ash, which restricts the use of the ash as a cement replacement. Controlling ammonia in ash is also of concern. If newer, “clean coal” combustion and gasification technologies are adopted, their byproducts may also present a management challenge. The objective of the Combustion Byproducts Recycling Consortium (CBRC) is to develop and demonstrate technologies to address issues related to the recycling of byproducts associated with coal combustion processes. A goal of CBRC is that these technologies, by the year 2010, will lead to an overall ash utilization rate from the current 34% to 50% by such measures as increasing the current rate of FGD byproduct use and increasing in the number of uses considered “allowable” under state regulations. Another issue of interest to the CBRC would be to examine the environmental impact of both byproduct utilization and disposal. No byproduct utilization technology is likely to be adopted by industry unless it is more cost-effective than landfilling. Therefore, it is extremely important that the utility industry provide guidance to the R&D program. Government agencies and privatesector organizations that may be able to utilize these materials in the conduct of their missions should also provide input. The CBRC will serve as an effective vehicle for acquiring and maintaining guidance from these diverse organizations so that the proper balance in the R&D program is achieved.

Ziemkiewicz, Paul; Vandivort, Tamara; Pflughoeft-Hassett, Debra; Chugh, Y Paul; Hower, James

2008-08-31

107

Ammonia Can Crush  

Microsoft Academic Search

When a 12-oz aluminum soft drink can filled with ammonia or hydrogen chloride gas is inverted and dipped into water, the rapidly dissolving gas evacuates the can and the can is crushed before water can be drawn into it. This demonstrates, among other things, the remarkable strength of hydrogen bonds.

Ed Vitz; Daniel T. Haworth

1999-01-01

108

Ammonia Can Crush  

NASA Astrophysics Data System (ADS)

When a 12-oz aluminum soft drink can filled with ammonia or hydrogen chloride gas is inverted and dipped into water, the rapidly dissolving gas evacuates the can and the can is crushed before water can be drawn into it. This demonstrates, among other things, the remarkable strength of hydrogen bonds.

Vitz, Ed

1999-07-01

109

Green Science: Revisiting Recycling  

ERIC Educational Resources Information Center

Recycling has been around for a long time--people have reused materials and refashioned them into needed items for thousands of years. More recently, war efforts encouraged conservation and reuse of materials, and in the 1970s recycling got its official start when recycling centers were created. Now, curbside recycling programs and recycling

Palliser, Janna

2011-01-01

110

Recycling Lesson Plans.  

ERIC Educational Resources Information Center

This document contains lesson plans about recycling for teachers in grades K-12. Titles include: (1) "Waste--Where Does It Come From? Where Does It Go?" (2) "Litter Detectives," (3) "Classroom Paper Recycling," (4) "Recycling Survey," (5) "Disposal and Recycling Costs," (6) "Composting Project," (7) Used Motor Oil Recycling," (8) "Unwrapping…

Pennsylvania State Dept. of Environmental Resources, Harrisburg.

111

Percolation of a general network of networks  

NASA Astrophysics Data System (ADS)

Percolation theory is an approach to study the vulnerability of a system. We develop an analytical framework and analyze the percolation properties of a network composed of interdependent networks (NetONet). Typically, percolation of a single network shows that the damage in the network due to a failure is a continuous function of the size of the failure, i.e., the fraction of failed nodes. In sharp contrast, in NetONet, due to the cascading failures, the percolation transition may be discontinuous and even a single node failure may lead to an abrupt collapse of the system. We demonstrate our general framework for a NetONet composed of n classic Erd?s-Rényi (ER) networks, where each network depends on the same number m of other networks, i.e., for a random regular network (RR) formed of interdependent ER networks. The dependency between nodes of different networks is taken as one-to-one correspondence, i.e., a node in one network can depend only on one node in the other network (no-feedback condition). In contrast to a treelike NetONet in which the size of the largest connected cluster (mutual component) depends on n, the loops in the RR NetONet cause the largest connected cluster to depend only on m and the topology of each network but not on n. We also analyzed the extremely vulnerable feedback condition of coupling, where the coupling between nodes of different networks is not one-to-one correspondence. In the case of NetONet formed of ER networks, percolation only exhibits two phases, a second order phase transition and collapse, and no first order percolation transition regime is found in the case of the no-feedback condition. In the case of NetONet composed of RR networks, there exists a first order phase transition when the coupling strength q (fraction of interdependency links) is large and a second order phase transition when q is small. Our insight on the resilience of coupled networks might help in designing robust interdependent systems.

Gao, Jianxi; Buldyrev, Sergey V.; Stanley, H. Eugene; Xu, Xiaoming; Havlin, Shlomo

2013-12-01

112

Directory of Arizona Recyclers.  

National Technical Information Service (NTIS)

The Department of Environmental Quality is providing a current directory of Arizona recyclers listed alphabetically by counties and types of recyclable materials. Local recyclers are listed alphabetically by name, address and phone number, along with the ...

1990-01-01

113

Entanglement percolation in quantum complex networks  

E-print Network

Quantum networks are essential to quantum information distributed applications, and communicating over them is a key challenge. Complex networks have rich and intriguing properties, which are as yet unexplored in the quantum setting. Here, we study the effect of entanglement percolation as a means to establish long-distance entanglement between arbitrary nodes of quantum complex networks. We develop a theory to analytically study random graphs with arbitrary degree distribution and give exact results for some models. Our findings are in good agreement with numerical simulations and show that the proposed quantum strategies enhance the percolation threshold substantially. Simulations also show a clear enhancement in small-world and other real-world networks.

M. Cuquet; J. Calsamiglia

2009-06-16

114

A phenomenological model of percolating magnetic nanostructures  

Microsoft Academic Search

:   Transport and magnetotransport properties were analysed systematically in percolating magnetic nanostructures such as Ni-rich\\u000a and films. These granular magnetic films exhibit giant Hall effect. We identified features which are common and unique to these\\u000a systems. Among the features are the correlation between a -like temperature dependent resistivity and a particle size distribution having a large fraction of small nanometer

S. K. Wong; B. Zhao; T. K. Ng; X. N. Jing; X. Yan; P. M. Hui

1999-01-01

115

Percolation in a gradient: conductivity properties  

NASA Astrophysics Data System (ADS)

The authors investigate the conductivity properties of a randomly diluted medium where the fraction of present bonds varies along the mean voltage drop, and reaches the percolation threshold. They obtain the scaling of the conductivity as a function of the system size for any concentration profile. They show that a transient scaling regime also appears for small system sizes and a rapidly varying concentration of bonds close to the threshold. Finally the distribution of local currents is also investigated.

Roux, S.; Hansen, A.; Hinrichsen, E. L.

1990-12-01

116

Cooperation percolation in spatial prisoner's dilemma game  

NASA Astrophysics Data System (ADS)

The paradox of cooperation among selfish individuals still puzzles scientific communities. Although a large amount of evidence has demonstrated that the cooperator clusters in spatial games are effective in protecting the cooperators against the invasion of defectors, we continue to lack the condition for the formation of a giant cooperator cluster that ensures the prevalence of cooperation in a system. Here, we study the dynamical organization of the cooperator clusters in spatial prisoner's dilemma game to offer the condition for the dominance of cooperation, finding that a phase transition characterized by the emergence of a large spanning cooperator cluster occurs when the initial fraction of the cooperators exceeds a certain threshold. Interestingly, the phase transition belongs to different universality classes of percolation determined by the temptation to defect b. Specifically, on square lattices, 1 < b < 4/3 leads to a phase transition pertaining to the class of regular site percolation, whereas 3/2 < b < 2 gives rise to a phase transition subject to invasion percolation with trapping. Our findings offer a deeper understanding of cooperative behavior in nature and society.

Yang, Han-Xin; Rong, Zhihai; Wang, Wen-Xu

2014-01-01

117

Ammonia in tritium systems  

Microsoft Academic Search

A recent tritium inventory imbalance at Mound required an investigation into its causes. Much tritium was found as HTO in unsuspected zeolite traps of a T-purification system. Isotopic exchange from ammonia was postulated as a mechanism for entry of T into the zeolitic water. Gases from a T-processing system which had experienced air in-leakage were shown, by trapping of condensibles,

J. T. Gill; R. E. Ellefson; R. P. Paulick; C. M. Colvin; R. L. Yauger; E. E. Johns; R. L. Anderson; E. L. Lewis; P. H. Lamberger; R. E. Vallee

1988-01-01

118

Ammonia in tritium systems  

Microsoft Academic Search

A recent tritium inventory imbalance at Mound required an investigation into its causes. Much tritium was found as HTO in unsuspected zeolite traps of a T-purification system. Isotropic exchange from ammonia was postulated as a mechanism for entry of T into the zeolitic water. Gases from a T-processing system which had experienced air in-leakage were shown, by trapping of condensibles,

J. T. Gill; R. E. Ellefson; R. P. Paulick; C. M. Colvin; R. L. Yauger; E. E. Johns; R. L. Anderson; E. L. Lewis; P. H. Lamberger; R. E. Vallee

1988-01-01

119

Topology of a percolating soil pore network  

NASA Astrophysics Data System (ADS)

A connectivity function defined by the 3D-Euler number, is a topological indicator and can be related to hydraulic properties (Vogel and Roth, 2001). This study aims to develop connectivity Euler indexes as indicators of the ability of soils for fluid percolation. The starting point was a 3D grey image acquired by X-ray computed tomography of a soil at bulk density of 1.2 mg cm-3. This image was used in the simulation of 40000 particles following a directed random walk algorithms with 7 binarization thresholds. These data consisted of 7 files containing the simulated end points of the 40000 random walks, obtained in Ruiz-Ramos et al. (2010). MATLAB software was used for computing the frequency matrix of the number of particles arriving at every end point of the random walks and their 3D representation. In a former work (Capa et al., 2011) a criteria for choosing the optimal threshold of grey value was identified: Final positions were divided in two subgroups, cg1 (positions with frequency of the number of particles received greater than the median) and cg2 (frequency lower or equal to median). Images with maximum difference between the Z coordinate of the center of gravity of both subgroups were selected as those with optimal threshold that reflects the major internal differences in soil structure that are relevant to percolation. According to this criterion, the optimal threshold for the soil with density 1.2 mg cm-3 was 24.Thresholds above and below the optimal (23 and 25) were also considered to confirm this selection; therefore the analysis were conducted for three files (1 image with 3 grey threshold values, which have different porosity). Additionally, three random matrix simulations with the same porosity than the selected binaries images were used to test the existence of pore connectivity as a consequence of a non-random soil structure. Therefore, 6 matrix were considered (three structured and three random) for this study. Random matrix presented a normal distribution of percolation speed contrary to the simulated percolation speed for structured soil images. For all of them, Minkowski functionals were calculated applying Ohser and Mucklich (2001) methodology. Interpretation of results in terms of soil percolation behavior of these soils will be derived.

Capa-Morocho, M.; Ruiz-Ramos, M.; Hapca, S. M.; Houston, A.; Tarquis, A. M.

2012-04-01

120

Percolation in a Proton Exchange Membrane Fuel Cell Catalyst Layer  

SciTech Connect

Water management in the catalyst layers of proton exchange membrane fuel cells (PEMFC) is confronted by two issues, flooding and dry out, both of which result in improper functioning of the fuel cell and lead to poor performance and degradation. At the present time, the data that has been reported about water percolation and wettability within a fuel cell catalyst layer is limited. A method and apparatus for measuring the percolation pressure in the catalyst layer has been developed based upon an experimental apparatus used to test water percolation in porous transport layers (PTL). The experimental setup uses a pseudo Hele-Shaw type testing where samples are compressed and a fluid is injected into the sample. Testing the samples gives percolation pressure plots which show trends in increasing percolation pressure with an increase in flow rate. A decrease in pressure was seen as percolation occurred in one sample, however the pressure only had a rising effect in the other sample.

Stacy, Stephen; Allen, Jeffrey

2012-07-01

121

Continuum percolation of carbon nanotubes in polymeric and colloidal media  

PubMed Central

We apply continuum connectedness percolation theory to realistic carbon nanotube systems and predict how bending flexibility, length polydispersity, and attractive interactions between them influence the percolation threshold, demonstrating that it can be used as a predictive tool for designing nanotube-based composite materials. We argue that the host matrix in which the nanotubes are dispersed controls this threshold through the interactions it induces between them during processing and through the degree of connectedness that must be set by the tunneling distance of electrons, at least in the context of conductivity percolation. This provides routes to manipulate the percolation threshold and the level of conductivity in the final product. We find that the percolation threshold of carbon nanotubes is very sensitive to the degree of connectedness, to the presence of small quantities of longer rods, and to very weak attractive interactions between them. Bending flexibility or tortuosity, on the other hand, has only a fairly weak impact on the percolation threshold. PMID:18550818

Kyrylyuk, Andriy V.; van der Schoot, Paul

2008-01-01

122

WASTE DESCRIPTION RECYCLED OR  

E-print Network

Batteries Recycled 7,250 Hazardous Waste $36,250 $0 $36,250 Estimate 50 lbs./battery and avoided disposalWASTE DESCRIPTION REDUCED, REUSED, RECYCLED OR CONSERVED POUNDS REDUCED, REUSED, RECYCLED OR CONSERVED IN 2000 WASTE TYPE POTENTIAL COSTS FOR TREATMENT & DISPOSAL COST OF RECYCLE, PREVENTION ESTIMATED

123

Devil's Staircases, Crackling Noise and Phase Transitions in Percolation  

NASA Astrophysics Data System (ADS)

We identify and study certain phenomena in percolation that can subvert predictability and controllability in networked systems. We establish devil's staircase phase transitions, non-self-averaging, and power-law fluctuations in percolation. We provide exact conditions for percolation that exhibits multiple discontinuous jumps in the order parameter where the position and magnitude of the jumps are randomly distributed - characteristic of crackling noise. The framework can be linked to magnetic effects and fragmentation processes.

Nagler, Jan

2013-03-01

124

Connectedness Percolation of Elongated Hard Particles in an External Field  

NASA Astrophysics Data System (ADS)

A theory is presented of how orienting fields and steric interactions conspire against the formation of a percolating network of, in some sense, connected elongated colloidal particles in fluid dispersions. We find that the network that forms above a critical loading breaks up again at higher loadings due to interaction-induced enhancement of the particle alignment. Upon approach of the percolation threshold, the cluster dimensions diverge with the same critical exponent parallel and perpendicular to the field direction, implying that connectedness percolation is not in the universality class of directed percolation.

Otten, Ronald H. J.; van der Schoot, Paul

2012-02-01

125

Correction-to-scaling exponent for two-dimensional percolation  

SciTech Connect

We show that the correction-to-scaling exponents in two-dimensional percolation are bounded by {Omega}{<=}72/91, {omega}=D{Omega}{<=}3/2, and {Delta}{sub 1}={nu}{omega}{<=}2, based upon Cardy's result for the crossing probability on an annulus. The upper bounds are consistent with many previous measurements of site percolation on square and triangular lattices and new measurements for bond percolation, suggesting that they are exact. They also agree with exponents for hulls proposed recently by Aharony and Asikainen, based upon results of den Nijs. A corrections scaling form evidently applicable to site percolation is also found.

Ziff, Robert M. [Center for the Study of Complex Systems and Department of Chemical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)

2011-02-15

126

Recycling of pavement materials  

E-print Network

materials. A comparison was made between the recycled pavements and typical conventional asphalt concrete pavements. An economic asse?sment of thc recycled pavements was made to determine thc economic feasibility of recycling. Results of laboratory... evaluations show that: recycled pavement mixtures possess properties equivalent to conventional asphalt concrete mixtures; and rccvcl inI' con ho accom- plished with conventional ertuapment. kyar po I'lotion associated with hot-mix recycling of asphalt...

O'Neal, Randy Jim

2012-06-07

127

Percolation Model of Adhesion at Polymer Interfaces  

NASA Astrophysics Data System (ADS)

Adhesion at polymer interfaces is treated as a percolation problem, where an areal density of chains ?, of length L, contribute a number of entanglements to the interface of thickness X. The fracture energy G, is determined by the fraction of entanglements P, fractured or disentangled in the deformation zone preceding the crack tip, via G ~ P-P_c, where Pc is the percolation threshold, given by Pc = 1- M_e/Mc . For incompatible A/B interfaces reinforced with ? diblocks or random A-B copolymers of effective length L'(L' ~ 0 for brushes and strongly adsorbed chains), we obtain P ~ ?L/X, Pc ~ ? _cL/X, such that G = K(? - ? _c)+ G_o, where K and Go ~ 1 J/m^2 are constants. Note that Log G vs Log ? will have an apparent slope of about 2, incorrectly suggesting that G ~ ? ^2. For cohesive fracture, disentanglement dominates at M M*, G = G*[1-M_c/M]. For fatigue crack propagation da/dN, at welding interfaces, we obtain da/dN ~ M-5/2(t/Tr)-5/4, where t is the welding time and Tr is the reptation time. For polymer-solid interfaces, G ~ (X/R)^2. where X is the conformational width of the first layer of chains of random coil size R. The fractal nature of the percolation process is relevant to the fracture mechanism and fractography.

Wool, Richard P.

1998-03-01

128

Modied invasion percolation model for fracking  

NASA Astrophysics Data System (ADS)

Recent developments in hydraulic fracturing (fracking) have enabled the recovery of large reserves of natural gas and oil. These developments include a change from low-volume, high-viscosity fluid injection to high-volume, low-viscosity injection. We consider new models of Invasion Percolation, (IP) which are models that were originally introduced to represent the injection of an invading fluid into a fluid filled porous medium. A primary difference between our model and the original model is the elimination of any unbroken bonds whose end sites are both filled with fluid. While the original model was found to have statistics nearly identical to traditional percolation, we find significant statistical differences. In particular, the distribution of broken bond strengths displays a strong roll-over near the critical point. Another difference between traditional percolation clusters and clusters generated using our model is the absence of internal loops. The modified growth rule prevents the formation of internal loops making the growing cluster ramified. Other ramified networks include drainage basins and DLA clusters. The study of drainage basins led to the development of Horton-Strahler and Tokunaga network statistics. We used both Horton-Strahler and Tokunaga network statistics to characterize simulated clusters using and found that the clusters generated by our model are statistically self-similar fractals. In addition to fractal clusters, IP also displays burst dynamics, in which the cluster extends rapidly through a spontaneous extension of percolating bonds. We define a burst to be a consecutive series of broken bonds whose strengths are all below a specified value. Using this definition of bursts we found good agreement with a power-law frequency-area distribution. Our model displays many of the characteristics of an energy landscape, and shows many similarities to DLA, neural networks, ecological landscapes, and the world wide web. We anticipate that this new class of models will have broad applicability to the study of instabilities in high dimensional complex networks, a topic of considerable interest across a wide array of fields.

Norris, J.; Turcotte, D. L.; Rundle, J. B.

2013-12-01

129

Bounds of percolation thresholds on hyperbolic lattices  

NASA Astrophysics Data System (ADS)

We analytically study bond percolation on hyperbolic lattices obtained by tiling a hyperbolic plane with constant negative Gaussian curvature. The quantity of our main concern is pc2, the value of occupation probability where a unique unbounded cluster begins to emerge. By applying the substitution method to known bounds of the order-5 pentagonal tiling, we show that pc2?0.382508 for the order-5 square tiling, pc2?0.472043 for its dual, and pc2?0.275768 for the order-5-4 rhombille tiling.

Lee, Junghoon F.; Baek, Seung Ki

2012-12-01

130

k-Core percolation on multiplex networks  

E-print Network

We generalize the theory of k-core percolation on complex networks to k-core percolation on multiplex networks, where k=(k_a, k_b, ...). Multiplex networks can be defined as networks with a set of vertices but different types of edges, a, b, ..., representing different types of interactions. For such networks, the k-core is defined as the largest sub-graph in which each vertex has at least k_i edges of each type, i = a, b, ... . We derive self-consistency equations to obtain the birth points of the k-cores and their relative sizes for uncorrelated multiplex networks with an arbitrary degree distribution. To clarify our general results, we consider in detail multiplex networks with edges of two types, a and b, and solve the equations in the particular case of ER and scale-free multiplex networks. We find hybrid phase transitions at the emergence points of k-cores except the (1,1)-core for which the transition is continuous. We apply the k-core decomposition algorithm to air-transportation multiplex networks, composed of two layers, and obtain the size of (k_a, k_b)-cores.

N. Azimi-Tafreshi; J. Gomez-Gardenes; S. N. Dorogovtsev

2014-05-06

131

k-core percolation on multiplex networks  

NASA Astrophysics Data System (ADS)

We generalize the theory of k-core percolation on complex networks to k-core percolation on multiplex networks, where k ?(k1,k2,...,kM). Multiplex networks can be defined as networks with vertices of one kind but M different types of edges, representing different types of interactions. For such networks, the k-core is defined as the largest subgraph in which each vertex has at least ki edges of each type, i =1,2,...,M. We derive self-consistency equations to obtain the birth points of the k-cores and their relative sizes for uncorrelated multiplex networks with an arbitrary degree distribution. To clarify our general results, we consider in detail multiplex networks with edges of two types and solve the equations in the particular case of Erd?s-Rényi and scale-free multiplex networks. We find hybrid phase transitions at the emergence points of k-cores except the (1,1)-core for which the transition is continuous. We apply the k-core decomposition algorithm to air-transportation multiplex networks, composed of two layers, and obtain the size of (k1,k2)-cores.

Azimi-Tafreshi, N.; Gómez-Gardeñes, J.; Dorogovtsev, S. N.

2014-09-01

132

Recycled Art: Create Puppets Using Recycled Objects.  

ERIC Educational Resources Information Center

Presents an activity from "Healthy Foods from Healthy Soils" for making puppets using recycled food packaging materials. Includes background information, materials, instructions, literature links, resources, and benchmarks. (NB)

Clearing, 2003

2003-01-01

133

Recycle Used Oil on America Recycles Day.  

ERIC Educational Resources Information Center

Explains that motor oils can be reused and recycled. Educates students about environmental hazards and oil management and includes classroom activities. Addresses the National Science Education Standards. (YDS)

White, Boyd W.

2000-01-01

134

Water Percolation Governs Polymorphic Transitions and Conductivity of DNA  

Microsoft Academic Search

We report on the first computer simulation studies of the percolation transition of water at the surface of the DNA double helix. With increased hydration, the ensemble of small clusters merges into a spanning water network via a quasi-two-dimensional percolation transition. This transition occurs strikingly close to the hydration level where the B form of DNA becomes stable in experiment.

Ivan Brovchenko; Aliaksei Krukau; Alla Oleinikova; Alexey K. Mazur

2006-01-01

135

Percolation approach to phase transitions in high energy nuclear collisions  

E-print Network

We study continuum percolation in nuclear collisions for the realistic case in which the nuclear matter distribution is not uniform over the collision volume, and show that the percolation threshold is increased compared to the standard, uniform situation. In terms of quark-gluon plasma formation this means that the phase transition threshold is pushed to higher energies.

A. Rodrigues; R. Ugoccioni; J. Dias de Deus

1998-12-15

136

Bootstrap percolation on homogeneous trees has 2 phase transitions  

E-print Network

Bootstrap percolation on homogeneous trees has 2 phase transitions L.R.G. Fontes R.H. Schonmann Abstract We study the threshold bootstrap percolation model on the homoge- neous tree with degree b + 1, 2 call pf , such that a) for p > pf , the final bootstrapped configuration is fully occupied for almost

Schonmann, Roberto H.

137

Noise excess on fractals and percolating systems R. Rammal (*)  

E-print Network

spectrum F(03C9) of the voltage fluctuations in a self-similar resistor network is determined. A finite denotes the random-walk exponent for diffusing par- ticles. For percolating networks in the critical has been studied near the percolation threshold [1-3]. Measurements were performed in [2] thin Au

Paris-Sud XI, Université de

138

Conducting-angle-based percolation in the XY model.  

PubMed

We define a percolation problem on the basis of spin configurations of the two-dimensional XY model. Neighboring spins belong to the same percolation cluster if their orientations differ less than a certain threshold called the conducting angle. The percolation properties of this model are studied by means of Monte Carlo simulations and a finite-size scaling analysis. Our simulations show the existence of percolation transitions when the conducting angle is varied, and we determine the transition point for several values of the XY coupling. It appears that the critical behavior of this percolation model can be well described by the standard percolation theory. The critical exponents of the percolation transitions, as determined by finite-size scaling, agree with the universality class of the two-dimensional percolation model on a uniform substrate. This holds over the whole temperature range, even in the low-temperature phase where the XY substrate is critical in the sense that it displays algebraic decay of correlations. PMID:20365707

Wang, Yancheng; Guo, Wenan; Nienhuis, Bernard; Blöte, Henk W J

2010-03-01

139

Conducting-angle-based percolation in the XY model  

NASA Astrophysics Data System (ADS)

We define a percolation problem on the basis of spin configurations of the two-dimensional XY model. Neighboring spins belong to the same percolation cluster if their orientations differ less than a certain threshold called the conducting angle. The percolation properties of this model are studied by means of Monte Carlo simulations and a finite-size scaling analysis. Our simulations show the existence of percolation transitions when the conducting angle is varied, and we determine the transition point for several values of the XY coupling. It appears that the critical behavior of this percolation model can be well described by the standard percolation theory. The critical exponents of the percolation transitions, as determined by finite-size scaling, agree with the universality class of the two-dimensional percolation model on a uniform substrate. This holds over the whole temperature range, even in the low-temperature phase where the XY substrate is critical in the sense that it displays algebraic decay of correlations.

Wang, Yancheng; Guo, Wenan; Nienhuis, Bernard; Blöte, Henk W. J.

2010-03-01

140

Critical transport and failure in continuum crack percolation Didier Somette  

E-print Network

transport and failure properties of a new class of continuum percolation systems (blue cheese model), where, distinct from their counterparts in both the discrete-lattice and Swiss-cheese continuum percolation models of the transport properties is similar to that of the Swiss cheese model developed by Halperin et al. For elastic

Paris-Sud XI, Université de

141

Electrical and Rheological Percolation in Polystyrene/MWCNT Nanocomposites  

E-print Network

the formation of a percolated MWCNT network that responds elastically over long timescales. Network formation black or nanoclays. The motivation for the present work is the potential use of polymer, and demonstrated the presence of a percolated network of SWCNTs at concentration exceeding 1.5 wt %. To dat

Raghavan, Srinivasa

142

INHOMOGENEOUS BOND PERCOLATION ON SQUARE, TRIANGULAR, AND HEXAGONAL  

E-print Network

lat- tices. Amongst the consequences are box-crossing (RSW) inequal- ities for such models adapted to the needs of the second. For ex- ample, the RSW box-crossing lemmas of [25, 26] have a key role and phrases. Bond percolation, inhomogeneous percolation, RSW lemma, box-crossing, star

Grimmett, Geoffrey

143

Equilibrium ammonium concentration in slurry mix evaporator condensate tank (SMECT) with ammonia scrubbers  

SciTech Connect

During design reviews of the Recycle Colection Tank (RCT) at the Savannah River Site it was determined that in all cases the RCT scrub solution could not be routed to the RCT. During transfers to the tank farm (estimated ten hour cycle), the ammonia evolved from the RCT is scrubbed by the RCT scrubber and the ammonia scrub water must be returned to the SMECT. The result of this is an increased steady state concentration of ammonium in the SMECT water used for the ammonia scrubbers. The maximum ammonium concentration is necessary for the sizing of the ammonia scrubbers for the Sludge Receipt and Adjustment Tank (SRAT),Slurry Mix Evaporator (SME), and RCT.

Lambert, D.P.

1992-09-25

144

Process for removal of ammonia and acid gases from contaminated waters  

DOEpatents

Contaminating basic gases, i.e., ammonia and acid gases, e.g., carbon dioxide, are removed from process waters or waste waters in a combined extraction and stripping process. Ammonia in the form of ammonium ion is extracted by an immiscible organic phase comprising a liquid cation exchange component, especially an organic phosphoric acid derivative, and preferably di-2-ethyl hexyl phosphoric acid, dissolved in an alkyl hydrocarbon, aryl hydrocarbon, higher alcohol, oxygenated hydrocarbon, halogenated hydrocarbon, and mixtures thereof. Concurrently, the acidic gaseous contaminants are stripped from the process or waste waters by stripping with stream, air, nitrogen, or the like. The liquid cation exchange component has the ammonia stripped therefrom by heating, and the component may be recycled to extract additional amounts of ammonia.

King, C.J.; Mackenzie, P.D.

1982-09-03

145

Crossover behavior of conductivity in a discontinuous percolation model  

NASA Astrophysics Data System (ADS)

When conducting bonds are occupied randomly in a two-dimensional square lattice, the conductivity of the system increases continuously as the density of those conducting bonds exceeds the percolation threshold. Such a behavior is well known in percolation theory; however, the conductivity behavior has not been studied yet when the percolation transition is discontinuous. Here we investigate the conductivity behavior through a discontinuous percolation model evolving under a suppressive external bias. Using effective medium theory, we analytically calculate the conductivity behavior as a function of the density of conducting bonds. The conductivity function exhibits a crossover behavior from a drastically to a smoothly increasing function beyond the percolation threshold in the thermodynamic limit. The analytic expression fits well our simulation data.

Kim, Seongmin; Cho, Y. S.; Araújo, N. A. M.; Kahng, B.

2014-03-01

146

ParadigmParadigm Concrete RecyclingConcrete Recycling  

E-print Network

ParadigmParadigm Concrete RecyclingConcrete Recycling #12;Recycled ConcreteRecycled Concrete ·· Whatever steel goes into PCC must comeWhatever steel goes into PCC must come out for recycleout for recycle ·· Aggregates have a big impact on the costAggregates have a big impact on the cost of recyclingof recycling

147

Federal Recycling Program Printed on Recycled Paper  

E-print Network

Federal Recycling Program Printed on Recycled Paper The Forest Service, U.S. Department activities: · Protection and management of resources on 191 million acres of National Forest System lands, age, disability, political beliefs, sexual orientation, and marital or familial status. (Not all

Standiford, Richard B.

148

Recycling Rules: Understanding Recycling and a MRF  

NSDL National Science Digital Library

In this activity, learners simulate the separation techniques that materials recovery facilities (MRFs) use and then design their own series of recycling techniques. Learners identify four ways recyclable materials can be separated and sorted at a MRF: conveyor belts, blowers, flotation, and magnetism.

Keep America Beautiful, Inc.

2010-01-01

149

Recycling advanced batteries  

Microsoft Academic Search

This abstract introduces results from OnTo Technology's innovative recycling process to produce new materials for new batteries from materials from spent batteries. Recycling spent batteries is a growing problem for the consumer electronics electric vehicle industries.

Steven E. Sloop

2008-01-01

150

Recycling overview in Sweden  

SciTech Connect

This article discusses the recycling programs currently in use in Sweden. Recycling of newspapers, batteries, plastics are all mentioned in this report by the Swedish Association of Public Cleansing and Solid Waste Management.

Not Available

1989-07-01

151

Bootstrap Percolation in Living Neural Networks  

NASA Astrophysics Data System (ADS)

Recent experimental studies of living neural networks reveal that their global activation induced by electrical stimulation can be explained using the concept of bootstrap percolation on a directed random network. The experiment consists in activating externally an initial random fraction of the neurons and observe the process of firing until its equilibrium. The final portion of neurons that are active depends in a non linear way on the initial fraction. The main result of this paper is a theorem which enables us to find the final proportion of the fired neurons, in the asymptotic case, in the case of random directed graphs with given node degrees as the model for interacting network. This gives a rigorous mathematical proof of a phenomena observed by physicists in neural networks.

Amini, Hamed

2010-11-01

152

Entropic Elasticity of Phantom Percolation Networks  

E-print Network

A new method is used to measure the stress and elastic constants of purely entropic phantom networks, in which a fraction $p$ of neighbors are tethered by inextensible bonds. We find that close to the percolation threshold $p_c$ the shear modulus behaves as $(p-p_c)^f$, where the exponent $f\\approx 1.35$ in two dimensions, and $f\\approx 1.95$ in three dimensions, close to the corresponding values of the conductivity exponent in random resistor networks. The components of the stiffness tensor (elastic constants) of the spanning cluster follow a power law $\\sim(p-p_c)^g$, with an exponent $g\\approx 2.0$ and 2.6 in two and three dimensions, respectively.

Oded Farago; Yacov Kantor

2000-09-12

153

Resistance distribution in the hopping percolation model.  

PubMed

We study the distribution function P (rho) of the effective resistance rho in two- and three-dimensional random resistor networks of linear size L in the hopping percolation model. In this model each bond has a conductivity taken from an exponential form sigma proportional to exp (-kappar) , where kappa is a measure of disorder and r is a random number, 0< or = r < or =1 . We find that in both the usual strong-disorder regime L/ kappa(nu) >1 (not sensitive to removal of any single bond) and the extreme-disorder regime L/ kappa(nu) <1 (very sensitive to such a removal) the distribution depends only on L/kappa(nu) and can be well approximated by a log-normal function with dispersion b kappa(nu) /L , where b is a coefficient which depends on the type of lattice, and nu is the correlation critical exponent. PMID:16090050

Strelniker, Yakov M; Havlin, Shlomo; Berkovits, Richard; Frydman, Aviad

2005-07-01

154

The Economics of Recycling.  

ERIC Educational Resources Information Center

Reports the findings of a study that documented 1992 costs of residential curbside recycling versus disposal systems in four Washington State cities: Seattle, Spokane, Bellingham, and Vancouver. Results indicated that recycling can be less expensive than disposal when the revenues obtained from selling recycled materials are considered. (MDH)

Bogert, Susan; Morris, Jeffrey

1993-01-01

155

The Sustainability of Recycling.  

ERIC Educational Resources Information Center

Describes the need for closing the business cycle in the recycling process. Discusses whether the government should mandate or the free market create uses for recycled products. Presents challenges associated with marketing recycled materials including what has been and what needs to be done to stimulate markets, encourage business, and balance…

Juniper, Christopher

1993-01-01

156

Cryogenic processing and recycling  

SciTech Connect

This article examines cryogenic processing and recycling of rubber and rubber products. The topics discussed include utilization of cryogenically recycled materials in the rubber industry, current status of the industry, economic benefit, performance advantage, environmental benefit, technology assessment, the future of cryogenic process and recycling.

Leyden, J.J.

1991-03-01

157

AQUEOUS AMMONIA EQUILIBRIUM - TABULATION OF PERCENT UN-IONIZED AMMONIA  

EPA Science Inventory

The percent of un-ionized ammonia as a function of pH and temperature in aqueous ammonia solutions of zero salinity is presented in tabular form over the following ranges: temperature 0.0 to 40.0 C in increments of 0.2 degree, and pH 5.00 to 12.00 in increments of 0.01 pH unit....

158

ENGINEERING DESIGN CONFIGURATIONS FOR BIOLOGICAL AMMONIA REMOVAL  

EPA Science Inventory

Many regions in the United States have excessive levels of nutrients including ammonia in their source waters. For example, farming and agricultural sources of ammonia in the Midwest contribute to relatively high levels of ammonia in many ground waters. Although ammonia in water ...

159

Breath Ammonia Analysis: Clinical Application and Measurement  

Microsoft Academic Search

This review covers in detail the complexity of human breath, how the body metabolizes ammonia, clinical conditions which are directly related to the regulation of ammonia concentration, and analysis of current techniques that are capable of detecting breath ammonia. Focusing on these areas provides the information needed to develop a breath ammonia sensor for monitoring dysfunction of the human body.

Troy Hibbard; Anthony J. Killard

2011-01-01

160

Multiple percolation tunneling staircase in metal-semiconductor nanoparticle composites  

NASA Astrophysics Data System (ADS)

Multiple percolation transitions are observed in a binary system of RuO2-CaCu3Ti4O12 metal-semiconductor nanoparticle composites near percolation thresholds. Apart from a classical percolation transition, associated with the appearance of a continuous conductance path through RuO2 metal oxide nanoparticles, at least two additional tunneling percolation transitions are detected in this composite system. Such behavior is consistent with the recently emerged picture of a quantum conductivity staircase, which predicts several percolation tunneling thresholds in a system with a hierarchy of local tunneling conductance, due to various degrees of proximity of adjacent conducting particles distributed in an insulating matrix. Here, we investigate a different type of percolation tunneling staircase, associated with a more complex conductive and insulating particle microstructure of two types of non-spherical constituents. As tunneling is strongly temperature dependent, we use variable temperature measurements to emphasize the hierarchical nature of consecutive tunneling transitions. The critical exponents corresponding to specific tunneling percolation thresholds are found to be nonuniversal and temperature dependent.

Mukherjee, Rupam; Huang, Zhi-Feng; Nadgorny, Boris

2014-10-01

161

Directed percolation effects emerging from superadditivity of quantum networks  

NASA Astrophysics Data System (ADS)

Entanglement-induced nonadditivity of classical communication capacity in networks consisting of quantum channels is considered. Communication lattices consisting of butterfly-type entanglement-breaking channels augmented, with some probability, by identity channels are analyzed. The capacity superadditivity in the network is manifested in directed correlated bond percolation which we consider in two flavors: simply directed and randomly oriented. The obtained percolation properties show that high-capacity information transfer sets in much faster in the regime of superadditive communication capacity than otherwise possible. As a by-product, this sheds light on a type of entanglement-based quantum capacity percolation phenomenon.

Czekaj, L.; Chhajlany, R. W.; Horodecki, P.

2012-03-01

162

Argon recovery from hydrogen depleted ammonia plant purge gas using a HARP Plant  

SciTech Connect

A number of ammonia plants employ membranes or cryogenic hydrogen recovery units to separate hydrogen contained in the purge gas for recycle to the ammonia synthesis loop. The resulting hydrogen depleted purge gas, which is usually used for fuel, is an attractive source of argon. This paper presents the novel features of a process which employs a combination of pressure swing adsorption (PSA) and cryogenic technology to separate the argon from this hydrogen depleted purge gas stream. This new proprietary Hybrid Argon Recovery Progress (HARP) plant is an effective alternative to a conventional all-cryogenic plant.

Krishnamurthy, R.; Lerner, S.L.; Maclean, D.L.

1987-01-01

163

Hydrogen diffusion and the percolation of austenite in nanostructured steel  

E-print Network

of hydrogen when the austenite decomposes below the value required to sustain percolation. The experiments have involved both thermal desorption analysis and permeation, and when combined with theoretical analysis, indicate a significant influence...

Fielding, L. C. D.; Song, E. J.; Han, D. K.; Bhadeshia, H. K. D. H.; Suh, D.-W.

2014-05-21

164

The glue-ball spectrum of pure percolation  

E-print Network

We present a high-precision numerical study of 3D random percolation viewed as a confining gauge theory. Using large correlation matrices among multiform Wilson loops we determine the low-lying masses in various spin channels.

Stefano Lottini; Ferdinando Gliozzi

2005-10-05

165

The percolation staircase model and its manifestation in composite materials  

NASA Astrophysics Data System (ADS)

We studied the tunneling percolation conductivity dependence on the site or bond occupation probability in the square lattice. The model predicts that in both, lattice and continuum systems in which there is a hierarchy of the local conductances, the dependence of the global conductivity on the site or volume occupation probability will yield a conductivity staircase. In particular we evaluate the implications of the staircase on the critical behavior of the conductivity. We then show experimental evidence for the predicted percolation-tunneling staircase in a Ag-Al2O3 granular metal system and in a carbon black-polymer composite. Following that, we propose that for carbon nanotube (CNT) polymer composites the data in the literature give ample support to a percolation-dispersion staircase behavior. The implication of the present findings on the percolation-hopping problem in composite materials is also discussed.

Balberg, I.; Azulay, D.; Goldstein, Y.; Jedrzejewski, J.; Ravid, G.; Savir, E.

2013-10-01

166

Casimir-like forces at the percolation transition.  

PubMed

Percolation and critical phenomena show common features such as scaling and universality. Colloidal particles, immersed in a solvent close to criticality, experience long-range effective forces named critical Casimir forces. Building on the analogy between critical phenomena and percolation, here we explore the possibility of observing long-range forces near a percolation threshold. To this aim, we numerically evaluate the effective potential between two colloidal particles dispersed in a chemical sol, and we show that it becomes attractive and long-ranged on approaching the sol percolation transition. We develop a theoretical description based on a polydisperse Asakura-Oosawa model that captures the divergence of the interaction range, allowing us to interpret such effect in terms of depletion interactions in a structured solvent. Our results provide the geometric analogue of the critical Casimir force, suggesting a novel way for tuning colloidal interactions by controlling the clustering properties of the solvent. PMID:24513667

Gnan, Nicoletta; Zaccarelli, Emanuela; Sciortino, Francesco

2014-01-01

167

Casimir-like forces at the percolation transition  

NASA Astrophysics Data System (ADS)

Percolation and critical phenomena show common features such as scaling and universality. Colloidal particles, immersed in a solvent close to criticality, experience long-range effective forces named critical Casimir forces. Building on the analogy between critical phenomena and percolation, here we explore the possibility of observing long-range forces near a percolation threshold. To this aim, we numerically evaluate the effective potential between two colloidal particles dispersed in a chemical sol, and we show that it becomes attractive and long-ranged on approaching the sol percolation transition. We develop a theoretical description based on a polydisperse Asakura-Oosawa model that captures the divergence of the interaction range, allowing us to interpret such effect in terms of depletion interactions in a structured solvent. Our results provide the geometric analogue of the critical Casimir force, suggesting a novel way for tuning colloidal interactions by controlling the clustering properties of the solvent.

Gnan, Nicoletta; Zaccarelli, Emanuela; Sciortino, Francesco

2014-02-01

168

Kinetic model for heterogeneous catalysis: Cluster and percolation properties  

NASA Astrophysics Data System (ADS)

A lattice model for heterogeneous catalysis on a flat metal surface (i.e., oxidation of carbon monoxide on platinum) has been investigated in mean field approximation and by Monte Carlo simulations. The cluster structure has been determined as a function of a single parameter YCO, directly related to the partial pressure of the carbon monoxide. At low YCO the surface is covered by a percolating oxygen cluster with small dispersed CO islands. As YCO is increased, the oxygen ceases to percolate. In parallel the CO clusters resp. the clusters of unoccupied sites increase in size and percolate just about when the system gets poisoned by the CO. The structure of the large clusters of all three types can be modeled by correlated percolation. The slowing down of the kinetics near the poisoning transition has been investigated and is shown to be related to the diffusion of clusters of unoccupied sites.

Kolb, M.; Boudeville, Y.

1990-03-01

169

Optical percolation and nonlinearity of sputtered Ag island films  

Microsoft Academic Search

The fractal dimension Df and the critical parameter nu of the sputtered percolation Ag island films are measured to be about 1.57 and 1.15, respectively. A modified Z-scan method including both transmittance Z-scan and reflection Z-scan is proposed to measure the pure nonlinear absorption of the semi-continuous Ag films near the percolation threshold. As the microstructure of the sputtered Ag

S. Ding; X. Wang; D. Chen; Q. Wang

2006-01-01

170

Water Percolation Governs Polymorphic Transitions and Conductivity of DNA  

NASA Astrophysics Data System (ADS)

We report on the first computer simulation studies of the percolation transition of water at the surface of the DNA double helix. With increased hydration, the ensemble of small clusters merges into a spanning water network via a quasi-two-dimensional percolation transition. This transition occurs strikingly close to the hydration level where the B form of DNA becomes stable in experiment. Formation of spanning water networks results in sigmoidlike acceleration of long-range ion transport in good agreement with experiment.

Brovchenko, Ivan; Krukau, Aliaksei; Oleinikova, Alla; Mazur, Alexey K.

2006-09-01

171

St Andrews Recycling Points Recycling Points are situated locally to  

E-print Network

St Andrews Recycling Points Recycling Points are situated locally to allow you to recycle the following materials: To find your nearest Recycling Point please visit www.fifedirect.org.uk/wasteaware or call the Recycling Helpline on 08451 55 00 22. R&A GOLF CLUB OLD COURSE HOTEL UNIVERSITY NORTH HAUGH

St Andrews, University of

172

Sol-gel-derived percolative copper film  

SciTech Connect

Cu-SiO{sub 2} films were prepared by the sol-gel method. Two-dimensional fractal copper films were formed after the films were thermally treated in reducing atmosphere. dc resistances of the films decrease 12 orders of magnitude as the content of copper increases from 70 to 80 mol%. During the resistance measurement under argon atmosphere, samples showed a sharp increase or decrease of resistance at a transition temperature which is ascribed to the oxidation of Cu into CuO. The oxidation was also observed in the in situ high temperature X-ray diffraction under vacuum condition. The evolution of the morphology of the films was studied by scanning electron microscopy. As the content of copper increases, the forms of copper particles change from discrete to aggregate then to interconnecting. The coverage coefficients of the copper range from 23 to 55% and the fractal dimensions range from 1.65 to 1.77. The percolation thresholds for the coverage coefficient and the fractal dimension are about 33% and 1.71, respectively, which corresponds to the sample containing 72.5 mol% of Cu.

Szu Sungping [Department of Physics, National Chung-Hsing University, Taichung 402, Taiwan (China)], E-mail: spszu@phys.nchu.edu.tw; Cheng, C.-L. [Department of Physics, National Chung-Hsing University, Taichung 402, Taiwan (China)

2008-10-02

173

Percolation and critical O(n) loop configurations  

NASA Astrophysics Data System (ADS)

We study a percolation problem based on critical loop configurations of the O(n) loop model on the honeycomb lattice. We define dual clusters as groups of sites on the dual triangular lattice that are not separated by a loop, and investigate the bond-percolation properties of these dual clusters. The universal properties at the percolation threshold are argued to match those of Kasteleyn-Fortuin random clusters in the critical Potts model. This relation is checked numerically by means of cluster simulations of several O(n) models in the range 1?n?2 . The simulation results include the percolation threshold for several values of n , as well as the universal exponents associated with bond dilution and the size distribution of the diluted clusters at the percolation threshold. Our numerical results for the exponents are in agreement with existing Coulomb-gas results for the random-cluster model, which confirms the relation between both models. We discuss the renormalization flow of the bond-dilution parameter p as a function of n , and provide an expression that accurately describes a line of unstable fixed points as a function of n , corresponding with the percolation threshold. Furthermore, the renormalization scenario indicates the existence, in a p versus n diagram, of another line of fixed points at p=1 , which is stable with respect to p .

Ding, Chengxiang; Deng, Youjin; Guo, Wenan; Blöte, Henk W. J.

2009-06-01

174

Organic reactivity in liquid ammonia.  

PubMed

Liquid ammonia is a useful solvent for many organic reactions including aliphatic and aromatic nucleophilic substitution and metal-ion catalysed reactions. The acidity of acids is modified in liquid ammonia giving rise to differences from conventional solvents. The ionisation constants of phenols and carbon acids are the product of those for ion-pair formation and dissociation to the free ions. There is a linear relationship between the pK(a) of phenols and carbon acids in liquid ammonia and those in water of slope 1.68 and 0.7, respectively. Aminium ions exist in their unprotonated free base form in liquid ammonia. The rates of solvolysis and aminolysis by neutral amines of substituted benzyl chlorides in liquid ammonia show little or no dependence upon ring substituents, in stark contrast with the hydrolysis rates of substituted benzyl halides in water which vary 10(7) fold. However, the rates of the reaction of phenoxide ions and amine anions with 4-substituted benzyl chlorides gives a Hammett ? = 1.1 and 0.93, respectively. The second order rate constants for the substitution of benzyl chlorides by neutral and anionic amines show a single Brønsted ?(nuc) = 0.21 whereas those for substituted phenoxide ions generate a Brønsted ?(nuc) = 0.40. The rates of aromatic nucleophilic substitution reactions in liquid ammonia are much faster than those in protic solvents indicating that liquid ammonia behaves like a typical dipolar aprotic solvent in its solvent effects on organic reactions. Nitrofluorobenzenes (NFB) readily undergo solvolysis in liquid ammonia but oxygen nucleophiles, such as alkoxide and phenoxide ions, displace the fluorine of 4-NFB in liquid ammonia to give the corresponding substitution product with little or no competing solvolysis product. The Brønsted ?(nuc) for the reaction of 4-NFB with para-substituted phenoxides is 0.91, indicative that the decomposition of the Meisenheimer ?-intermediate is rate limiting. The aminolysis of 4-NFB occurs without general base catalysis by the amine and the second order rate constants generate a Brønsted ?(nuc) of 0.36, which is also interpreted in terms of rate limiting breakdown of the Meisenheimer ?-intermediate. PMID:22538452

Ji, Pengju; Atherton, John; Page, Michael I

2012-08-14

175

Recycling Service Learning Activity  

NSDL National Science Digital Library

The recycling project begins with students learning about waste and resources. They complete background assignments about the energy and materials required to manufacture paper, aluminum, etc. They study landfills and the issues related to space, pollution, etc. They look at what is different if these things are recycled. The students work in groups of two or three and adopt and academic building on campus. They educate the staff and faculty about recycling - what can be recycled and where. They arrange to pick-up paper from each office. My hope is that the college faculty, staff and students will eventually recycle paper at common bins and that our project will progress to adding other recyclables to our project.

Faatz, Renee

176

Recycle plastics into feedstocks  

Microsoft Academic Search

Thermal cracking of mixed-plastics wastes with a fluidized-bed reactor can be a viable and cost-effective means to meet mandatory recycling laws. Strict worldwide environmental statutes require the hydrocarbon processing industry (HPI) to develop and implement product applications and technologies that reuse post-consumer mixed-plastics waste. Recycling or reuse of plastics waste has a broad definition. Recycling entails more than mechanical regranulation

H. Kastner; W. Kaminsky

1995-01-01

177

Announcing: All Recycling Reduce your  

E-print Network

Announcing: All Recycling Go Green! Reduce your contribution to the landfill, by choosing to voluntarily recycle acceptable items in the green All Recycling toters and containers around campus. ONLY THE ITEMS BELOW ARE ACCEPTED FOR ALL RECYCLING Please do not contaminate the recycling containers with trash

Papautsky, Ian

178

Factors Influencing Household Recycling Behavior  

Microsoft Academic Search

To investigate factors encouraging or deterring recycling, telephone interviews were used to study recycling behavior, attitudes, and knowledge of 221 randomly selected adults in a suburban city that had begun a citywide curbside recycling program within the past year. Approximately 40% reported participation in the curbside recycling program, and nearly 20% more claimed that their household had been recycling in

Stuart Oskamp; Maura J. Harrington; Todd C. Edwards; Deborah L. Sherwood; Shawn M. Okuda; Deborah C. Swanson

1991-01-01

179

The Ammonia Dimer Revisited  

NASA Astrophysics Data System (ADS)

The conclusion from microwave spectra by Nelson, Fraser, and Klemperer that the ammonia dimer has a nearly cyclic structure led to much debate about the issue of whether (NH_3)_2 is hydrogen bonded. This structure was surprising because most {ab initio} calculations led to a classical, nearly linear, hydrogen-bonded structure. An obvious explanation of the discrepancy between the outcome of these calculations and the microwave data which led Nelson {et al.} to their ``surprising structure'' might be the effect of vibrational averaging: the electronic structure calculations focus on finding the minimum of the intermolecular potential, the experiment gives a vibrationally averaged structure. Isotope substitution studies seemed to indicate, however, that the complex is nearly rigid. Additional data became available from high-resolution molecular beam far-infrared spectroscopy in the Saykally group. These spectra, displaying large tunneling splittings, indicate that the complex is very floppy. The seemingly contradictory experimental data were explained when it became possible to calculate the vibration-rotation-tunneling (VRT) states of the complex on a six-dimensional intermolecular potential surface. The potential used was a simple model potential, with parameters fitted to the far-infrared data. Now, for the first time, a six-dimensional potential was computed by high level {ab initio} methods and this potential will be used in calculations of the VRT states of (NH_3)_2 and (ND_3)_2. So, we will finally be able to answer the question whether the conclusions from the model calculations are indeed a valid explanation of the experimental data. D. Nelson, G. T. Fraser, and W. Klemperer J. Chem. Phys. 83 6201 (1985) J. G. Loeser, C. A. Schmuttenmaer, R. C. Cohen, M. J. Elrod, D. W. Steyert, R. J. Saykally, R. E. Bumgarner, and G. A. Blake J. Chem. Phys. 97 4727 (1992) E. H. T. Olthof, A. van der Avoird, and P. E. S. Wormer J. Chem. Phys. 101 8430 (1994) E. H. T. Olthof, A. van der Avoird, P. E. S. Wormer, J. G. Loeser, and R. J. Saykally J. Chem. Phys. 101 8443 (1994)

Dawes, Richard; Van Der Avoird, Ad

2012-06-01

180

Michigan Recycled Materials Market Directory.  

National Technical Information Service (NTIS)

The Michigan Recycled Materials Market Directory is being made available to commercial, industrial, municipal and institutional recyclers in the State of Michigan to assist in finding markets for accumulated or collected recyclable materials. The director...

1990-01-01

181

Desulfurization in the reducing state and denitrification with ammonia injection in an FBC test facility  

Microsoft Academic Search

The second generation PFBC-CC, IGCC, and the technology of staged combustion to lower emissions of NOx raise questions about the desulfurization efficiency under reducing atmosphere. This paper describes desulfurization tests in reducing atmosphere in a fluidized bed combustor with the application of the fly-ash recycle and two-staged combustion technologies. Also, ammonia injection was carried out. Results show that desulfurization in

Zhong Zhaoping; Lan Jixiang

1998-01-01

182

Colorimetric Analysis of Ammonia in Water.  

National Technical Information Service (NTIS)

An accurate, reliable method of determing concentration of ammonia in water solution was developed using colorimetric techniques. The procedure involves formation of a colored complex of ammonia with 2,5-dimethoxyoxolane and (E)-p-dimethylamino-cinnamalde...

F. W. Carson, R. L. Gross

1977-01-01

183

Plastic Recycling Toter -ORANGE  

E-print Network

Plastic Recycling Toter - ORANGE Glass Recycling Toter - TEAL Garbage Yellow sharps container - bulk rinsing for small items - Clear Glass - Broken glass is ok - rinsed 3 times - may have contained - Plastic disposable pipettes - Micropipette tips - Petri dishes - cell well plates - racks - Glass

Toronto, University of

184

Reuse, Reduce, Recycle.  

ERIC Educational Resources Information Center

Discussion of recycling paper in law libraries is also applicable to other types of libraries. Results of surveys of law libraries that investigated recycling practices in 1987 and again in 1990 are reported, and suggestions for reducing the amount of paper used and reusing as much as possible are offered. (LRW)

Briscoe, Georgia

1991-01-01

185

Recycling and Composting  

NSDL National Science Digital Library

In this lesson, students learn about the value of renewable resources. Using multimedia intractives, video, and classroom activities, they learn to identify examples of renewable resources and how humans use them, understand what recycling and conservation are, learn about composting, and identify food waste and household items that can be recycled or composted.

2005-01-01

186

Recycling into Art  

NSDL National Science Digital Library

This interdisciplinary unit weaves art and science together to help students appreciate the importance of recycling. In this engaging activity, students collected items worthy of recycling from home, and with the help of the art teacher, used a loom to cr

Fioranelli, Debra

2000-10-01

187

The Fermilab recycler ring  

SciTech Connect

The Fermilab Recycler is a permanent magnet storage ring for the accumulation of antiprotons from the Antiproton Source, and the recovery and cooling of the antiprotons remaining at the end of a Tevatron store. It is an integral part of the Fermilab III luminosity upgrade. The following paper describes the design features, operational and commissioning status of the Recycler Ring.

Martin Hu

2001-07-24

188

Partnership: Recycling $/$ Outdoor Education.  

ERIC Educational Resources Information Center

The Ottawa Board of Education (Ontario, Canada) has committed revenues generated by a districtwide recycling program to help fund the MacSkimming Outdoor Education Centre. A partnership between recycling and outdoor education is valuable in developing an environmental ethic among students and in finding new ways to fund outdoor education. (LP)

Weir, Phil

1996-01-01

189

Using ammonia as a sustainable fuel  

Microsoft Academic Search

In this study, ammonia is identified as a sustainable fuel for mobile and remote applications. Similar to hydrogen, ammonia is a synthetic product that can be obtained either from fossil fuels, biomass, or other renewable sources. Some advantages of ammonia with respect to hydrogen are less expensive cost per unit of stored energy, higher volumetric energy density that is comparable

C. Zamfirescu; I. Dincer

2008-01-01

190

46 CFR 154.1760 - Liquid ammonia.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Liquid ammonia. 154.1760 Section...VESSELS CARRYING BULK LIQUEFIED GASES Special Design and Operating Requirements § 154.1760 Liquid ammonia. The master shall ensure that no person sprays liquid ammonia into a cargo tank...

2010-10-01

191

Hydrogen production using ammonia borane  

DOEpatents

Hydrogen ("H.sub.2") is produced when ammonia borane reacts with a catalyst complex of the formula L.sub.nM-X wherein M is a base metal such as iron, X is an anionic nitrogen- or phosphorus-based ligand or hydride, and L is a neutral ancillary ligand that is a neutral monodentate or polydentate ligand.

Hamilton, Charles W; Baker, R. Thomas; Semelsberger, Troy A; Shrestha, Roshan P

2013-12-24

192

The Kozeny-Carman equation with a percolation threshold.  

PubMed

A procedure has been developed for calculating permeability (k) from the Kozeny-Carman equation, a procedure that links ideas from percolation theory with the ideas of Koltermann and Gorelick (1995) and Esselburn et al. (2011). The approach focuses on the proportion of coarser pores that are occupied by finer sediments relative to a percolation threshold proportion (?(c)). If the proportion occupied is below ?(c), then the unoccupied coarser pores percolate. Otherwise they do not percolate. Following the ideas of Koltermann and Gorelick (1995), the effective grain-size term in the Kozeny-Carman equation is calculated using the geometric mean if the unoccupied coarse pores percolate, and using the harmonic mean if otherwise. Following ideas of Esselburn et al. (2011), this approach is implemented by evaluating the potential for grains in each size category to occupy pores among sediment of each larger-size category. Application of these ideas to physical sediment models for sands and gravels, which have known k, indicates that a threshold does indeed exist. Results also suggest that the Kozeny-Carman equation is robust and gives representative values for k, even though ?(c) is not precisely known. PMID:22509896

Porter, Lee B; Ritzi, Robert W; Mastera, Lawrence J; Dominic, David F; Ghanbarian-Alavijeh, Behzad

2013-01-01

193

Memory decay and loss of criticality in quorum percolation  

NASA Astrophysics Data System (ADS)

In this paper, we present the effects of memory decay on a bootstrap percolation model applied to random directed graphs (quorum percolation). The addition of decay was motivated by its natural occurrence in physical systems previously described by percolation theory, such as cultured neuronal networks, where decay originates from ionic leakage through the membrane of neurons and/or synaptic depression. Surprisingly, this feature alone appears to change the critical behavior of the percolation transition, where discontinuities are replaced by steep but finite slopes. Using different numerical approaches, we show evidence for this qualitative change even for very small decay values. In experiments where the steepest slopes can not be resolved and still appear as discontinuities, decay produces nonetheless a quantitative difference on the location of the apparent critical point. We discuss how this shift impacts network connectivity previously estimated without considering decay. In addition to this particular example, we believe that other percolation models are worth reinvestigating, taking into account similar sorts of memory decay.

Renault, Renaud; Monceau, Pascal; Bottani, Samuel

2013-12-01

194

Recycle Used Oil on America Recycles Day  

NSDL National Science Digital Library

Motor oil doesn't wear out--it just gets dirty. Students and the general public may not know that used oil can be reused or recycled. The fact is, used oil can be re-fined, blended with additives, and used again. When you consider that 1.4 billion gallons

White, Boyd W.

2000-11-01

195

Transcriptional response of the archaeal ammonia oxidizer Nitrosopumilus maritimus to low and environmentally relevant ammonia concentrations.  

PubMed

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (?500 ?M) and the other well below the Km (<10 nM). Transcript levels were generally immediately and differentially repressed when cells transitioned from ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

Nakagawa, Tatsunori; Stahl, David A

2013-11-01

196

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations  

PubMed Central

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (?500 ?M) and the other well below the Km (<10 nM). Transcript levels were generally immediately and differentially repressed when cells transitioned from ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

Stahl, David A.

2013-01-01

197

Loopless non-trapping invasion percolation model for fracking  

E-print Network

Recent developments in hydraulic fracturing (fracking) have enabled the recovery of large quantities of natural gas and oil from old, low permeability shales. These developments include a change from low-volume, high-viscosity fluid injection to high-volume, low-viscosity injection. The injected fluid introduces distributed damage that provides fracture permeability for the extraction of the gas and oil. In order to model this process, we utilize a loopless non-trapping invasion percolation previously introduced to model optimal polymers in a strongly disordered medium, and for determining minimum energy spanning trees on a lattice. We performed numerical simulations on a 2D square lattice and find significant differences from other percolation models. Additionally, we find that the growing fracture network satisfies both Horton-Strahler and Tokunaga network statistics. As with other invasion percolation models, our model displays burst dynamics, in which the cluster extends rapidly into a connected region. W...

Norris, J Quinn; Rundle, John B

2014-01-01

198

Explosive percolation: Unusual transitions of a simple model  

NASA Astrophysics Data System (ADS)

In this paper we review the recent advances in explosive percolation, a very sharp phase transition first observed by Achlioptas et al. (2009). There a simple model was proposed, which changed slightly the classical percolation process so that the emergence of the spanning cluster is delayed. This slight modification turns out to have a great impact on the percolation phase transition. The resulting transition is so sharp that it was termed explosive, and it was at first considered to be discontinuous. This surprising fact stimulated considerable interest in “Achlioptas processes”. Later work, however, showed that the transition is continuous (at least for Achlioptas processes on Erdös networks), but with very unusual finite size scaling. We present a review of the field, indicate open “problems” and propose directions for future research.

Bastas, N.; Giazitzidis, P.; Maragakis, M.; Kosmidis, K.

199

Percolation Perturbations in Potential Theory and Random Walks  

E-print Network

We show that on a Cayley graph of a nonamenable group, almost surely the infinite clusters of Bernoulli percolation are transient for simple random walk, that simple random walk on these clusters has positive speed, and that these clusters admit bounded harmonic functions. A principal new finding on which these results are based is that such clusters admit invariant random subgraphs with positive isoperimetric constant. We also show that percolation clusters in any amenable Cayley graph almost surely admit no nonconstant harmonic Dirichlet functions. Conversely, on a Cayley graph admitting nonconstant harmonic Dirichlet functions, almost surely the infinite clusters of $p$-Bernoulli percolation also have nonconstant harmonic Dirichlet functions when $p$ is sufficiently close to 1. Many conjectures and questions are presented.

Itai Benjamini; Russell Lyons; Oded Schramm

1998-04-02

200

Connecting Core Percolation and Controllability of Complex Networks  

PubMed Central

Core percolation is a fundamental structural transition in complex networks related to a wide range of important problems. Recent advances have provided us an analytical framework of core percolation in uncorrelated random networks with arbitrary degree distributions. Here we apply the tools in analysis of network controllability. We confirm analytically that the emergence of the bifurcation in control coincides with the formation of the core and the structure of the core determines the control mode of the network. We also derive the analytical expression related to the controllability robustness by extending the deduction in core percolation. These findings help us better understand the interesting interplay between the structural and dynamical properties of complex networks. PMID:24946797

Jia, Tao; Pósfai, Márton

2014-01-01

201

Double site-bond percolation model for biomaterial implants  

E-print Network

We present a double site-bond percolation model to account, on the one hand, for the vascularization and/or resorption of biomaterial implant in bones and, on the other hand, for its mechanical continuity. The transformation of the implant into osseous material, and the dynamical formation/destruction of this osseous material is accounted for by creation and destruction of links and sites in two, entangled, networks. We identify the relevant parameters to describe the implant and its evolution, and separate their biological or chemical origin from their physical one. We classify the various phenomena in the two regimes, percolating or non-percolating, of the networks. We present first numerical results in two dimensions.

Mely, H

2011-01-01

202

RecycleMania! Improving Waste Reduction and Recycling on  

E-print Network

RecycleMania! Improving Waste Reduction and Recycling on Campus from Universities to Big Business #12;Contact Information Tracy Artley Recycling Coordinator University of Michigan Tel: 734-763-5539 Email: recycle@umich.edu #12;Agenda Waste Impacts of Large Institutions Unique Challenges Overcoming

Awtar, Shorya

203

Correlated percolation models of structured habitat in ecology  

NASA Astrophysics Data System (ADS)

Percolation offers acknowledged models of random media when the relevant medium characteristics can be described as a binary feature. However, when considering habitat modeling in ecology, a natural constraint comes from nearest-neighbor correlations between the suitable/unsuitable states of the spatial units forming the habitat. Such constraints are also relevant in the physics of aggregation where underlying processes may lead to a form of correlated percolation. However, in ecology, the processes leading to habitat correlations are in general not known or very complex. As proposed by Hiebeler (2000), these correlations can be captured in a lattice model by an observable aggregation parameter q, supplementing the density p of suitable sites. We investigate this model as an instance of correlated percolation. We analyze the phase diagram of the percolation transition and compute the cluster size distribution, the pair-connectedness function C(r) and the correlation function g(r). We find that while g(r) displays a power-law decrease associated with long-range correlations in a wide domain of parameter values, critical properties are compatible with the universality class of uncorrelated percolation. We contrast the correlation structures obtained respectively for the correlated percolation model and for the Ising model, and show that the diversity of habitat configurations generated by the Hiebeler model is richer than the archetypal Ising model. We also find that emergent structural properties are peculiar to the implemented algorithm, leading to questioning the notion of a well-defined model of aggregated habitat. We conclude that the choice of model and algorithm has strong consequences on what insights ecological studies can get using such models of species habitat.

Huth, Géraldine; Lesne, Annick; Munoz, François; Pitard, Estelle

2014-12-01

204

Motivation recycling: pre-recycling case study in Minsk, Belarus.  

PubMed

Given the aim of motivating householders to behave in a recycling-friendly manner, there is a need to understand consumers' recycling behaviour. This paper documents and analyses acceptability and awareness of a pre-recycling society, through a survey carried out in the region of Minsk, Belarus. The results show a large number of people have no strong awareness about separate collection of household waste for recycling. By analysing the pre-recycling behaviour of Minsk citizens and substantive comparison with literature studies of a more mature recycling society such as Sweden, we indicate common sociodemographic variables for both cases and determine that these sociodemographic characteristics will directly influence recycling behaviour in countries like Belarus. It is also noted that the lack of recycling habit cannot directly predict subsequent recycling behaviour on the stage of implementation the recycling system. PMID:20124319

Miafodzyeva, Sviatlana; Brandt, Nils; Olsson, Monika

2010-04-01

205

GNB battery recycling plant  

SciTech Connect

The most technologically and environmentally advanced recycling plant in the world has just been completed in Columbus, Georgia, according to GNB. GNB Technologies is a wholly owned subsidiary of Pacific Dunlop. With a capacity of 9 million spent batteries per year, or 30,000 batteries a day, this new $50 million dollar plant replaces GNB`s 35-year old recycling plant in Columbus and increases recycling capacity there five-fold. The new plant will not produce any hazardous waste or sulfur emissions and the operation continuously reuses process water, completely eliminating effluent. The plant produces sodium sulfate from the battery acid, creating a third marketable product besides plastic and lead.

Hopkins, G.E.

1995-08-01

206

Dragnet: Nonprofit Computer Recyclers  

NSDL National Science Digital Library

If you have ever wondered what happens to obsolete computers, check out these current awareness Websites. The disposal of computers is classified as hazardous waste, which has become an environmental concern as the number of obsolete computers rises. In fact, the Wisconsin Department of Natural Resources and the State of Massachusetts have banned computer equipment from landfills. Dragnet: Nonprofit Computer Recyclers is an EPA-licensed computer recycling organization that reuses all acceptable components and systems or recycles damaged or unusable components. Rebuilt computer systems are given to "persons with disabilities and persons living in disadvantaged situations."

207

Percolation approach to study connectivity in living neural networks  

NASA Astrophysics Data System (ADS)

We study neural connectivity in cultures of rat hippocampal neurons. We measure the neurons' response to an electric stimulation for gradual lower connectivity, and characterize the size of the giant cluster in the network. The connectivity undergoes a percolation transition described by the critical exponent ? ? 0.65. We use a theoretic approach based on bond—percolation on a graph to describe the process of disintegration of the network and extract its statistical properties. Together with numerical simulations we show that the connectivity in the neural culture is local, characterized by a gaussian degree distribution and not a power law one.

Soriano, Jordi; Breskin, Ilan; Moses, Elisha; Tlusty, Tsvi

2007-02-01

208

Quenched invariance principle for simple random walk on percolation clusters  

E-print Network

We consider the simple random walk on the (unique) infinite cluster of super-critical bond percolation in $\\Z^d$ with $d\\ge2$. We prove that, for almost every percolation configuration, the path distribution of the walk converges weakly to that of non-degenerate, isotropic Brownian motion. Our analysis is based on the consideration of a harmonic deformation of the infinite cluster on which the random walk becomes a square-integrable martingale. The size of the deformation, expressed by the so called corrector, is estimated by means of ergodicity arguments.

Noam Berger; Marek Biskup

2005-03-25

209

Remnant percolative disorder in highly-cured networks  

SciTech Connect

The authors have previously reported viscoelastic measurements demonstrating that fully-cured networks and critical gels exhibit similar relaxation spectra, implying that fully-cured networks are somewhat ill- connected. Here, they present restricted valence percolation simulations of networks well beyond the percolation transition that explicitly display remnant disorder over length scales less than the correlation length of the network. They conclude that the topology of highly-cured networks is not well described by a regular three- dimensional tennis net but is ill-connected over length scales that correspond to relaxation modes of practical interest.

Adolf, D.; Hance, B.; Martin, J.E. (Sandia National Labs., Albuquerque, NM (United States))

1993-05-24

210

RECYCLING RATE STUDY Prepared by  

E-print Network

NATIONAL RECYCLING RATE STUDY Prepared by: Smith, Bucklin and Associates, Inc. Market Research and Statistics Division Chicago, Illinois July 2003 PRINTED ON RECYCLED PAPER #12;BCI RECYCLING RATE STUDY TABLE ....................................................................................................1 II. METHODOLOGY A. Total Pounds of Lead Recycled from Batteries

Laughlin, Robert B.

211

Authorization Recycling in RBAC Systems  

E-print Network

Authorization Recycling in RBAC Systems 1Laboratory for Education and Research in Secure Systems ·motivation ·recycling approach recycling algorithms experimental evaluations summary & future work #12 issued before (precise recycling) #12;6 Laboratory for Education and Research in Secure Systems

212

RETHINKING WASTE, RECYCLING, AND HOUSEKEEPING  

E-print Network

RETHINKING WASTE, RECYCLING, AND HOUSEKEEPING EFFICIENCY.EFFICIENCY. A l GA leaner Green #12 t R li Management Recycling Staff The Office of Waste Reduction & Recycling started in The Office of Waste Reduction & Recycling started in 1990, we have 14 full time staff positions. ·We collect over 40

Howitt, Ivan

213

Nottingham Trent University Plastic Recycling  

E-print Network

5015/03/08 Nottingham Trent University Plastic Recycling Water and fizzy drinks bottles the caps from any bottles you recycle. Please rinse all plastic bottles and containers before putting them in the recycling bins. #12;5015/03/08 Nottingham Trent University Paper Recycling Office paper Catalogues

Evans, Paul

214

Degree-ordered percolation on a hierarchical scale-free network  

NASA Astrophysics Data System (ADS)

We investigate the critical phenomena of the degree-ordered percolation (DOP) model on the hierarchical (u,v) flower network with u ?v. Highest degree nodes are linked directly without intermediate nodes for u =1, while this is not the case for u ?1. Using the renormalization-group-like procedure, we derive the recursion relations for the percolating probability and the percolation order parameter, from which the percolation threshold and the critical exponents are obtained. When u ?1, the DOP critical behavior turns out to be identical to that of the bond percolation with a shifted nonzero percolation threshold. When u =1, the DOP and the bond percolation have the same vanishing percolation threshold but the critical behaviors are different. Implication to an epidemic spreading phenomenon is discussed.

Lee, Hyun Keun; Shim, Pyoung-Seop; Noh, Jae Dong

2014-06-01

215

New Computer Programs Using Diurnal Temperature Time Series to Determine Streambed Percolation Velocities  

NASA Astrophysics Data System (ADS)

Streambed percolation is one of the most important routes for groundwater recharge. Among many methods, using diurnal temperature in the streambed to determine percolation velocity is one the most frequently used methods. Several numerical codes, VS2DH, SUTRA, and TOUGH2, have been developed primarily for 2D or 3D heat transport simulation and also for use in streambed percolation velocity calculation, but, with great complexity. This research simplifies percolation velocity calculation by developing new computer codes that solve the 1D heat transfer equation. Using diurnal temperature data, percolation velocity can be determined easily to each day of the monitoring period. More percolation velocity data will enable more understanding for the river/groundwater interaction. This work also conducts a field test for studying streambed percolation in the Choshui stream, Central Taiwan. The data show the average percolation velocity at approximately 6.8×10-6 m/s.

Chen, W.; Chen, J.; Lu, W.; Huang, C.

2012-12-01

216

Making Recycled Paper  

NSDL National Science Digital Library

In this activity on page 11 of the PDF, learners follow simple steps to recycle old newspaper into new paper. Use this activity to introduce conservation as well as the chemistry of cellulose and how paper products are made.

Society, American C.

2011-01-01

217

Geodynamics: Christmas recycling  

NASA Astrophysics Data System (ADS)

The mechanisms for forming the abundant volcanic islands on ocean floors are debated. The geochemical signature of volcanic rocks from the northeast Indian Ocean suggests that seamounts there formed from melting recycled ancient continental rocks.

Gibson, Sally A.

2011-12-01

218

Coming round to recycling  

Microsoft Academic Search

Increasing numbers of people are trying to reduce and recycle their domestic waste, but hospitals have been slower to get the message. David Hutchins and Stuart White look at the potential environmental and financial benefits

David C J Hutchins; Stuart M White

2009-01-01

219

Fermilab recycler diagnostics  

SciTech Connect

The Fermilab Recycler Ring is a permanent magnet storage ring for the storage and cooling of antiprotons. The following note describes the diagnostic tools currently available for commissioning, as well as the improvements and upgrades planned for the near future.

Martin Hu

2001-07-24

220

Ammonia synthesis at low temperatures  

NASA Astrophysics Data System (ADS)

Density functional theory (DFT) calculations of reaction paths and energies for the industrial and the biological catalytic ammonia synthesis processes are compared. The industrial catalyst is modeled by a ruthenium surface, while the active part of the enzyme is modeled by a MoFe6S9 complex. In contrast to the biological process, the industrial process requires high temperatures and pressures to proceed, and an explanation of this important difference is discussed. The possibility of a metal surface catalyzed process running at low temperatures and pressures is addressed, and DFT calculations have been carried out to evaluate its feasibility. The calculations suggest that it might be possible to catalytically produce ammonia from molecular nitrogen at low temperatures and pressures, in particular if energy is fed into the process electrochemically.

Rod, T. H.; Logadottir, A.; Nørskov, J. K.

2000-03-01

221

GNB battery recycling plant  

Microsoft Academic Search

The most technologically and environmentally advanced recycling plant in the world has just been completed in Columbus, Georgia, according to GNB. GNB Technologies is a wholly owned subsidiary of Pacific Dunlop. With a capacity of 9 million spent batteries per year, or 30,000 batteries a day, this new $50 million dollar plant replaces GNB`s 35-year old recycling plant in Columbus

1995-01-01

222

Recyclability Index for Automobiles  

Microsoft Academic Search

A rating system was developed to quantify the environmental impacts of light-duty motor vehicles at the end of their life-cycle based on recyclability, toxic material content and ultimate disposal. Each year, 10-11 million vehicles are retired from service in the United States. The vehicle material not recycled is called automotive shredder residue (ASR). About 4.5 to 5 million tons of

Alexander Tsuji; Yarrow Nelson; Andrew Kean; Samuel A. Vigil

2006-01-01

223

Climate Kids: Recycle This!  

NSDL National Science Digital Library

The site features an online game in which participants keep recyclable items out of the trash by guiding them into proper bins. Accompanying the game is a list of three categories of items that can be recycled, along with the benefits of doing so. This lesson is part of the Climate Kids website, a NASA education resource featuring articles, videos, images and games focused on the science of climate change.

224

Recycling of nonmetallics  

USGS Publications Warehouse

The first factor determining recyclability is the composition of the material itself. Metals, for example, can be reused with little or no loss in quality. Paper and rubber, by this criterion, are less recyclable. Each time paper is recycled, some cellulose fibers are broken. Shorter fibers can mean weaker paper of perceived lower quality and value. Vulcanizing is an irreversible chemical process that precludes recycling rubber in its original form. Both materials may be reused in other applications often of lower value than the original one. To be recyclable, the discarded material must have a collection infrastructure at the source of waste generation, at a central collection site, or at curbside. The recovered material must also have a market. If it is priced noncompetitively or no market exists, if it does not meet specifications, or if it requires special technology investments which cannot be recovered through future sales, the recovered material may be stockpiled or discarded rather than recycled. ?? 1996 International Association for Mathematical Geology.

Amey, E.B.; Kelly, T.D.

1996-01-01

225

Percolation model for the existence of a mitochondrial Eve  

E-print Network

to a small range depending on the probability p that a newborn child is a female. 1 Introduction Percolation for p pc. They look thus like toy models for Statistical Mechanics and in fact be found in the subcellular organelles called mitochondria. These structures are present in large numbers

226

A Simple Soil Percolation Test Device for Field Environmentalists  

ERIC Educational Resources Information Center

A primary responsibility of field environmental health workers is evaluation of individual sewage disposal system sites. The authors of this article developed a practical, accurate, and inexpensive measurement device for obtaining reliable percolation test results. Directions for the construction and use of the device are detailed. Drawings…

Smith, William H.; Stark, Phillip E.

1977-01-01

227

Epidemics and percolation in small-world networks  

Microsoft Academic Search

We study some simple models of disease transmission on small-world networks, in which either the probability of infection by a disease or the probability of its transmission is varied, or both. The resulting models display epidemic behavior when the infection or transmission probability rises above the threshold for site or bond percolation on the network, and we give exact solutions

Cristopher Moore; M. E. J. Newman

2000-01-01

228

Monotonicity in first-passage percolation Jean-Baptiste Gouere  

E-print Network

(n-1). In [4], Howard proved the monotocity for an Euclidean first-passage percolation model. We are not aware of any other positive results. On the other hand, van den Berg proved in [7] that, when d = 2, one was given by Joshi in [6]. We refer to the review by Howard [5] for a more detailed account. Further remarks

Boyer, Edmond

229

The Use of Percolating Filters in Teaching Ecology.  

ERIC Educational Resources Information Center

Using percolating filters (components of sewage treatment process) reduces problems of organization, avoids damage to habitats, and provides a local study site for field work or rapid collection of biological material throughout the year. Component organisms are easily identified and the habitat can be studied as a simple or complex system.…

Gray, N. F.

1982-01-01

230

Phase diagram of inhomogeneous percolation with a defect plane  

E-print Network

Let ${\\mathbb{L}}$ be the $d$-dimensional hypercubic lattice and let ${\\mathbb{L}}_0$ be an $s$-dimensional sublattice, with $2 \\leq s densities $p$ and $\\sigma$, in which edges in ${\\mathbb{L}}\\setminus {\\mathbb{L}}_0$ are open with probability $p$, and edges in ${\\mathbb{L}}_0$ open with probability $\\sigma$. We generalizee several classical results of (homogeneous) bond percolation to this inhomogeneous model. The phase diagram of the model is presented, and it is shown that there is a subcritical regime for $\\sigmap_c(d)$, and a surface supercritical regime for $p\\sigma^*(p)$. We show that $\\sigma^*(p)$ is a strictly decreasing function for $p\\in[0,p_c(d)]$, with a jump discontinuity at $p_c(d)$. We extend the Aizenman-Barsky differential inequalities for homogeneous percolation to the inhomogeneous model and use them to prove that the susceptibility is finite inside the subcritical phase. We prove that the cluster size distribution decays exponentially in the subcritical phase, and sub-exponentially in the supercritical phases. For a model of lattice animals with a defect plane, the free energy is related to functions of the inhomogeneous percolation model, and we show how the percolation transition implies a non-analyticity in the free energy of the animal model. Finally, we present simulation estimates of the critical curve $\\sigma^*(p)$.

G. K. Iliev; E. J. Janse van Rensburg; N. Madras

2014-06-24

231

Percolative theories of strongly disordered ceramic high-temperature superconductors  

PubMed Central

Optimally doped ceramic superconductors (cuprates, pnictides, etc.) exhibit transition temperatures T c much larger than strongly coupled metallic superconductors like Pb (T c = 7.2 K, E g/kT c = 4.5) and exhibit many universal features that appear to contradict the Bardeen, Cooper, and Schrieffer theory of superconductivity based on attractive electron-phonon pairing interactions. These complex materials are strongly disordered and contain several competing nanophases that cannot be described effectively by parameterized Hamiltonian models, yet their phase diagrams also exhibit many universal features in both the normal and superconductive states. Here we review the rapidly growing body of experimental results that suggest that these anomalously universal features are the result of marginal stabilities of the ceramic electronic and lattice structures. These dual marginal stabilities favor both electronic percolation of a dopant network and rigidity percolation of the deformed lattice network. This “double percolation” model has previously explained many features of the normal-state transport properties of these materials and is the only theory that has successfully predicted strict lowest upper bounds for T c in the cuprate and pnictide families. Here it is extended to include Coulomb correlations and percolative band narrowing, as well as an angular energy gap equation, which rationalizes angularly averaged gap/T c ratios, and shows that these are similar to those of conventional strongly coupled superconductors. PMID:20080578

Phillips, J. C.

2010-01-01

232

Logarithmic operator intervals in the boundary theory of critical percolation  

E-print Network

We consider the sub-sector of the $c=0$ logarithmic conformal field theory (LCFT) generated by the boundary condition changing (bcc) operator in two dimensional critical percolation. This operator is the zero weight Kac operator $\\phi_{1,2}$, identified with the growing hull of the SLE$_6$ process. We identify percolation configurations with the significant operators in the theory. We consider operators from the first four bcc operator fusions: the identity and bcc operator; the stress tensor and its logarithmic partner; the derivative of the bcc operator and its logarithmic partner; and the pre-logarithmic operator $\\phi_{1,3}$. We construct several intervals in the percolation model, each associated to one of the LCFT operators we consider, allowing us to calculate crossing probabilities and expectation values of crossing cluster numbers. We review the Coulomb gas, which we use as a method of calculating these quantities when the number of bcc operator makes a direct solution to the system of differential equations intractable. Finally we discuss the case of the six-point correlation function, which applies to crossing probabilities between the sides of a conformal hexagon. Specifically we introduce an integral result that allows one to identify the probability that a single percolation cluster touches three alternating sides a hexagon with free boundaries. We give results of the numerical integration for the case of a regular hexagon.

Jacob J H Simmons

2013-11-21

233

The electrical conductivity of binary disordered systems, percolation clusters, fractals and related models  

Microsoft Academic Search

We review theoretical and experimental studies of the AC dielectric response of inhomogeneous materials, modelled as bond percolation networks, with a binary (conductor-dielectric) distribution of bond conductances. We first summarize the key results of percolation theory, concerning mostly geometrical and static (DC) transport properties, with emphasis on the scaling properties of the critical region around the percolation threshold. The frequency-dependent

J. P. Clerc; G. Giraud; J. M. Laugier; J. M. Luck

1990-01-01

234

PERCOLATION SINCE SAINT-FLOUR GEOFFREY R. GRIMMETT AND HARRY KESTEN  

E-print Network

PERCOLATION SINCE SAINT-FLOUR GEOFFREY R. GRIMMETT AND HARRY KESTEN 1. Introduction There has been a great deal of interest and activity in percolation theory since the two Saint-Flour courses, [76, 111, [27]. There has been in addition a third Saint-Flour course on percolation, on the Wulff con

Grimmett, Geoffrey

235

Dense Percolation in Large-Scale Mean-Field Random Networks is Provably "Explosive"  

E-print Network

1 Dense Percolation in Large-Scale Mean-Field Random Networks is Provably "Explosive" Alexander Recent reports suggest that evolving large-scale networks exhibit "explosive percolation": a large In recent years, "explosive percolation" in large-scale random networks has received substantial attention

Krokhmal, Paul

236

Network representation of pore scale imagery for percolation models  

NASA Astrophysics Data System (ADS)

Multiphase flow under capillary dominated flow regimes is driven by an intricate relationship between pore geometry, material and fluid properties. In this research, high-resolution micro-computed tomography (CT) imaging experiments are used to investigate structural and surface properties of bead packs, and how they influence percolation pathways. Coreflood experiments use a mix of hydrophilic and hydrophobic beads to track the influence of variable contact angle on capillary flow. While high-resolution CT images can render micron scale representation of the pore space, data must be upscaled to capture pore and pore throat geometry for use in percolation models. In this analysis, the pore space is upscaled into a network representation based on properties of the medial axis. Finding the medial axis using micron scale images is computationally expensive. Here, we compare the efficiency and accuracy of medial axes using erosion-based and watershed algorithms. The resulting network representation is defined as a ball-and-stick model which represents pores and pore throats. The ball-and-stick model can be further reduced by eliminating sections of the network that fall below a capillary pressure threshold. In a system of mixed hydrophilic and hydrophobic beads, capillary pressure can change significantly throughout the network based on the interaction between surface and fluid properties. The upscaled network representations are used in percolation models to estimate transport pathway. Current results use a basic percolation model that sequentially fills neighboring pores with the highest potential. Future work will expand the percolation model to include additional mechanics, such as trapping, vacating pores, and viscous fingering. Results from the coreflood experiments will be used to validate upscaling techniques and percolation models. Preliminary results show that the relative strength of water-wet and oil-wet surfaces has a significant impact on percolation. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Klise, K. A.; McKenna, S. A.; Read, E.; Karpyn, Z. T.; Celauro, J.

2012-12-01

237

The abundance threshold for plague as a critical percolation phenomenon.  

PubMed

Percolation theory is most commonly associated with the slow flow of liquid through a porous medium, with applications to the physical sciences. Epidemiological applications have been anticipated for disease systems where the host is a plant or volume of soil, and hence is fixed in space. However, no natural examples have been reported. The central question of interest in percolation theory, the possibility of an infinite connected cluster, corresponds in infectious disease to a positive probability of an epidemic. Archived records of plague (infection with Yersinia pestis) in populations of great gerbils (Rhombomys opimus) in Kazakhstan have been used to show that epizootics only occur when more than about 0.33 of the burrow systems built by the host are occupied by family groups. The underlying mechanism for this abundance threshold is unknown. Here we present evidence that it is a percolation threshold, which arises from the difference in scale between the movements that transport infectious fleas between family groups and the vast size of contiguous landscapes colonized by gerbils. Conventional theory predicts that abundance thresholds for the spread of infectious disease arise when transmission between hosts is density dependent such that the basic reproduction number (R(0)) increases with abundance, attaining 1 at the threshold. Percolation thresholds, however, are separate, spatially explicit thresholds that indicate long-range connectivity in a system and do not coincide with R(0) = 1. Abundance thresholds are the theoretical basis for attempts to manage infectious disease by reducing the abundance of susceptibles, including vaccination and the culling of wildlife. This first natural example of a percolation threshold in a disease system invites a re-appraisal of other invasion thresholds, such as those for epidemic viral infections in African lions (Panthera leo), and of other disease systems such as bovine tuberculosis (caused by Mycobacterium bovis) in badgers (Meles meles). PMID:18668107

Davis, S; Trapman, P; Leirs, H; Begon, M; Heesterbeek, J A P

2008-07-31

238

Thermodynamic Properties of Aqueous Solution of Ammonia  

NASA Astrophysics Data System (ADS)

Present status on the thermodynamic properties of experimental data and their correlations of both ammonia and aqueous solution of ammonia was introduced in this paper. The aqueous solution of ammonia is used for not only a working fluid in absorption refrigerator cycles but also working fluids in bottoming cycles of steam power plants and other heat recovering systems. Therefore, the thermodynamic properties of this substance are required in a wide range of temperatures, pressures and compositions. The experimental results of pVTx properties for ammonia and aqueous solution of ammonia and their comparisons with a formulation by Tillner-Roth and Friend1) were critically surveyed. The “Guideline on the IAPWS Formulation 2000 for the Thermodynamic Properties of Ammonia-Water Mixtures”, correlated by Tillner-Roth and Friend1), was approved on September, 2001, by the International Association for the Properties of Water and Steam (IAPWS) 2).

Kitamura, Hiroshi; Oguchi, Kosei

239

Diethylamine and ammonia pretreatment of lignocellulose  

E-print Network

to liberate the ammonia. An unmeasured excess of boric acid (HBO, ) in the recovery flask is then combined with the ammonia to form ammonium ions and borate ions. The borate ions are strong bases and can be titrated with a standard solution of hydrochloric... acid. At the equivalence point, the solution contains boric acid and ammonium ions. An indicator with an acid transition interval, such as bromocresol green, is required. 38 3. 0 RESULTS 3. 1 Ammonia Pretreatments of Coastal Bermudagrass Before...

Holthus, Robert Earl

2012-06-07

240

Reversible intercalation of ammonia molecules into a layered double hydroxide structure without exchanging nitrate counter-ions  

SciTech Connect

A zinc/aluminum LDH was precipitated with recycled ammonia from a chemical vapor deposition reaction. The LDH presented a crystalline phase with basal distance of 8.9 A, typical for nitrate-containing LDHs, and another phase with a basal distance of 13.9 A. Thermal treatment at 150 {sup o}C eliminated the phase with the bigger basal distance leaving only the anhydrous nitrate-intercalated LDH structure with 8.9 A. Intense N-H stretching modes in the FTIR spectra suggested that the expansion was due to intercalation of ammonia in the form of [NH{sub 4}(NH{sub 3}){sub n}]{sup +} species. When additional samples were precipitated with pure ammonia, the conventional LDH nitrate structure was obtained (8.9 A basal distance) at pH=7, as well as a pure crystalline phase with 13.9 A basal distance at pH=10 due to ammonia intercalation that can be removed by heating at 150 {sup o}C or by stirring in acetone, confirming a unusual sensu stricto intercalation process into a LDH without exchanging nitrate ions. - Graphical abstract: LDH-nitrate precipitated with ammonia expands the interlayer space if ammonia is bubbled up to pH 10. The basal distance decreased when the compound was heated at 150 {sup o}C or stirred in acetone. Nitrate ions are not exchanged.

Carbajal Arizaga, Gregorio Guadalupe, E-mail: gregoriocarbajal@yahoo.com.m [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia, Km. 107 Carretera Tijuana-Ensenada, Apdo. Postal 14, C.P. 22800. Ensenada, Baja California (Mexico); Wypych, Fernando [CEPESQ-Research Centre of Applied Chemistry, Department of Chemistry, Federal University of Parana, P.O. Box 19081, 81531-980 Curitiba, PR (Brazil); Castillon Barraza, Felipe; Contreras Lopez, Oscar Edel [Universidad Nacional Autonoma de Mexico, Centro de Nanociencias y Nanotecnologia, Km. 107 Carretera Tijuana-Ensenada, Apdo. Postal 14, C.P. 22800. Ensenada, Baja California (Mexico)

2010-10-15

241

Scrap tire recycling  

SciTech Connect

As the automobile tire technology has grown and met the need for safer and more durable tires, stronger reinforcement and more chemically resistant rubber compounds have made recycling tires more difficult. In an effort to resolve this problem, techniques and equipment were developed to grind tires into small pieces, and new markets were sought to utilize the crumb rubber product streams from ground tires. Industrial combustion processes were modified to accept scrap tires as fuel. These efforts have been beneficial, steadily increasing the percentage of scrap tires recycled to about 10% in 1985, and reaching 72% in 1995. By the end of 1997, fully 100% of tires generated in the U.S. are expected to be recycled.

Lula, J.W.; Bohnert, G.W.

1997-03-01

242

Recycled Aluminum Ornaments  

NSDL National Science Digital Library

This lesson plan from ATEEC will explain the principles of recycling. The activity would be most appropriate for technology studies or high school science classes. In all, it would require 2-5 hours of class time to complete. The purpose of the lesson is to demonstrate how aluminum is recycled. This laboratory activity does require some special equipment including a heat source capable of melting aluminum and an outdoor work area. Extension activities are also provided. The lesson plan is available for download as a PDF; users must create a free, quick login with ATEEC to access the materials.

Wishart, Ray

2013-06-14

243

Power recycling for an interferometric gravitational wave  

E-print Network

THESIS Power recycling for an interferometric gravitational wave detector Masaki Ando Department . . . . . . . . . . . . . . 48 3.3 Power recycling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3.3.1 Principle of power recycling . . . . . . . . . . . . . . . . . 50 3.3.2 Recycling cavity

Ejiri, Shinji

244

Randomness versus deterministic chaos: Effect on invasion percolation clusters  

NASA Astrophysics Data System (ADS)

What is the difference between randomness and chaos \\? Although one can define randomness and one can define chaos, one cannot easily assess the difference in a practical situation. Here we compare the results of these two antipodal approaches on a specific example. Specifically, we study how well the logistic map in its chaotic regime can be used as quasirandom number generator by calculating pertinent properties of a well-known random process: invasion percolation. Only if ?>?*1 (the first reverse bifurcation point) is a smooth extrapolation in system size possible, and percolation exponents are retrieved. If ??1, a sequential filling of the lattice with the random numbers generates a measurable anisotropy in the growth sequence of the clusters, due to short-range correlations.

Peng, Chung-Kang; Prakash, Sona; Herrmann, Hans J.; Stanley, H. Eugene

1990-10-01

245

Percolating ion transport in binary mixtures with high dielectric loss  

NASA Astrophysics Data System (ADS)

We investigate the ion transport percolation properties of a binary system of an ion conductor (NaCl) and an insulator (ethyl cellulose) for which the ac component of the conductivity is non-negligible over the entire measured frequency range. We find that the dc conductivity, extracted from a well-defined range of frequencies, can be described by a low percolation threshold, ?c=0.06 three-dimensional conducting network. The low ?c was explained by the water-layer-assisted ion conduction in micrometer-sized ethyl cellulose channels between NaCl grains. The present findings provide valuable knowledge for the analysis and design of a broad class of ion conducting functional materials.

Brohede, U.; Strømme, M.

2006-05-01

246

Percolation threshold determines the optimal population density for public cooperation.  

PubMed

While worldwide census data provide statistical evidence that firmly link the population density with several indicators of social welfare, the precise mechanisms underlying these observations are largely unknown. Here we study the impact of population density on the evolution of public cooperation in structured populations and find that the optimal density is uniquely related to the percolation threshold of the host graph irrespective of its topological details. We explain our observations by showing that spatial reciprocity peaks in the vicinity of the percolation threshold, when the emergence of a giant cooperative cluster is hindered neither by vacancy nor by invading defectors, thus discovering an intuitive yet universal law that links the population density with social prosperity. PMID:22587213

Wang, Zhen; Szolnoki, Attila; Perc, Matjaž

2012-03-01

247

The September 11 attack: A percolation of individual passive support  

NASA Astrophysics Data System (ADS)

A model to terrorism is presented using the theory of percolation. Terrorism power is related to the spontaneous formation of random backbones of people who are sympathetic to terrorism but without being directly involved in it. They just don't oppose in case they could. In the past such friendly-to-terrorism backbones have been always existing but were of finite size and localized to a given geographical area. The September 11 terrorist attack on the US has revealed for the first time the existence of a world wide spread extension. It is argued to have result from a sudden world percolation of otherwise unconnected and dormant world spread backbones of passive supporters. The associated strategic question is then to determine if collecting ground information could have predict and thus avoid such a transition. Our results show the answer is no, voiding the major criticism against intelligence services. To conclude the impact of military action is discussed.

Galam, S.

2002-04-01

248

Percolation, Bose-Einstein condensation, and string proliferation.  

PubMed

The close analogy between cluster percolation and string proliferation in the context of critical phenomena is studied. Like clusters in percolation theory, closed strings, which can be either finite-temperature worldlines or topological line defects, are described by a distribution parametrized by only two exponents. On approaching the critical point, the string tension vanishes and the loops proliferate, thereby signalling the onset of Bose-Einstein condensation (in the case of worldlines) or the disordering of the ordered state (in the case of vortices). The ideal Bose gas with modified energy spectrum is used as a stepping stone to derive general expressions for the critical exponents in terms of the two exponents parametrizing the loop distribution near criticality. PMID:11308550

Schakel, A M

2001-02-01

249

Percolation of interacting classical dimers on the square lattice  

NASA Astrophysics Data System (ADS)

We study the percolation properties of the interacting classical dimer model on the square lattice by means of Monte Carlo simulations and finite-size scaling analysis. We define Ising clusters based on the dimer configuration; the percolation point of the clusters coincides with the critical point of the Kosterlitz-Thouless transition of the dimer model, which is Tc=0.654(2). Furthermore, we find that the largest cluster at the Kosterlitz-Thouless point is a fractal, with fractal dimension Dc=1.874(2), which coincides with the critical exponent describing the critical behavior of the dimer-dimer correlation function, which is theoretically predicted to be 15/8.

Li, Yang; Wu, Dayan; Huang, Xianshan; Ding, Chengxiang

2014-06-01

250

Transport via Classical Percolation at Quantum Hall Plateau Transitions  

NASA Astrophysics Data System (ADS)

We consider transport properties of disordered two-dimensional electron gases under high perpendicular magnetic field, focusing in particular on the peak longitudinal conductivity ? peakxx at the quantum Hall plateau transition. We use a local conductivity model, valid at temperatures high enough such that quantum tunneling is suppressed, taking into account the random drift motion of the electrons in the disordered potential landscape and inelastic processes provided by electron-phonon scattering. A diagrammatic solution of this problem is proposed, which leads to a rich interplay of conduction mechanisms, where classical percolation effects play a prominent role. The scaling function for ? peakxx is derived in the high temperature limit, which can be used to extract universal critical exponents of classical percolation from experimental data.

Flöser, Martina; Florens, Serge; Champel, Thierry

2013-10-01

251

Unusual percolation in simple small-world networks.  

PubMed

We present an exact solution of percolation in a generalized class of Watts-Strogatz graphs defined on a one-dimensional underlying lattice. We find a nonclassical critical point in the limit of the number of long-range bonds in the system going to zero, with a discontinuity in the percolation probability and a divergence in the mean finite-cluster size. We show that the critical behavior falls into one of three regimes depending on the proportion of occupied long-range to unoccupied nearest-neighbor bonds, with each regime being characterized by different critical exponents. The three regimes can be united by a single scaling function around the critical point. These results can be used to identify the number of long-range links necessary to secure connectivity in a communication or transportation chain. As an example, we can resolve the communication problem in a game of "telephone." PMID:19658569

Cohen, Reuven; Dawid, Daryush Jonathan; Kardar, Mehran; Bar-Yam, Yaneer

2009-06-01

252

Quantum percolation in cuprate high-temperature superconductors  

PubMed Central

Although it is now generally acknowledged that electron–phonon interactions cause cuprate superconductivity with Tc values ?100 K, the complexities of atomic arrangements in these marginally stable multilayer materials have frustrated both experimental analysis and theoretical modeling of the remarkably rich data obtained both by angle-resolved photoemission (ARPES) and high-resolution, large-area scanning tunneling microscopy (STM). Here, we analyze the theoretical background in terms of our original (1989) model of dopant-assisted quantum percolation (DAQP), as developed further in some two dozen articles, and apply these ideas to recent STM data. We conclude that despite all of the many difficulties, with improved data analysis it may yet be possible to identify quantum percolative paths. PMID:18626024

Phillips, J. C.

2008-01-01

253

Vulnerability of networks: Fractional percolation on random graphs  

NASA Astrophysics Data System (ADS)

We present a theoretical framework for understanding nonbinary, nonindependent percolation on networks with general degree distributions. The model incorporates a partially functional (PF) state of nodes so that both intensity and extensity of error are characterized. Two connected nodes in a PF state cannot sustain the load and therefore break their link. We give exact solutions for the percolation threshold, the fraction of giant cluster, and the mean size of small clusters. The robustness-fragility transition point for scale-free networks with a degree distribution pk?k-? is identified to be ? =3. The analysis reveals that scale-free networks are vulnerable to targeted attack at hubs: a more complete picture of their Achilles' heel turns out to be not only the hubs themselves but also the edges linking them together.

Shang, Yilun

2014-01-01

254

Percolation and cooperation with mobile agents: Geometric and strategy clusters  

E-print Network

We study the conditions for persistent cooperation in an off-lattice model of mobile agents playing the Prisoner's Dilemma game with pure, unconditional strategies. Each agent has an exclusion radius rP, which accounts for the population viscosity, and an interaction radius rint, which defines the instantaneous contact network for the game dynamics. We show that, differently from the rP=0 case, the model with finite-sized agents presents a coexistence phase with both cooperators and defectors, besides the two absorbing phases, in which either cooperators or defectors dominate. We provide, in addition, a geometric interpretation of the transitions between phases. In analogy with lattice models, the geometric percolation of the contact network (i.e., irrespective of the strategy) enhances cooperation. More importantly, we show that the percolation of defectors is an essential condition for their survival. Differently from compact clusters of cooperators, isolated groups of defectors will eventually become extin...

Vainstein, Mendeli H; Arenzon, Jeferson J

2014-01-01

255

Transport in tight-binding bond percolation models  

NASA Astrophysics Data System (ADS)

Most of the investigations to date on tight-binding, quantum percolation models focused on the quantum percolation threshold, i.e., the analog to the Anderson transition. It appears to occur if roughly 30% of the hopping terms are actually present. Thus, models in the delocalized regime may still be substantially disordered, hence analyzing their transport properties is a nontrivial task which we pursue in the paper at hand. Using a method based on quantum typicality to numerically perform linear response theory we find that conductivity and mean free paths are in good accord with results from very simple heuristic considerations. Furthermore we find that depending on the percentage of actually present hopping terms, the transport properties may or may not be described by a Drude model. An investigation of the Einstein relation is also presented.

Schmidtke, Daniel; Khodja, Abdellah; Gemmer, Jochen

2014-09-01

256

Network Robustness and Fragility: Percolation on Random Graphs  

Microsoft Academic Search

Recent work on the internet, social networks, and the power grid has\\u000aaddressed the resilience of these networks to either random or targeted\\u000adeletion of network nodes. Such deletions include, for example, the failure of\\u000ainternet routers or power transmission lines. Percolation models on random\\u000agraphs provide a simple representation of this process, but have typically been\\u000alimited to graphs

Duncan S. Callaway; M. E. J. Newman; Steven H. Strogatz; Duncan J. Watts

2000-01-01

257

Low-field Hall effect near the percolation threshold  

Microsoft Academic Search

We use a random-resistor-network model to study the critical behavior of the low-field Hall constant in a three-dimensional (3D) metal-insulator composite near the percolation threshold. The transfer-matrix method, which was originally introduced for calculating conductivity, is generalized to be applicable to the calculation of the Hall constant and the magnetoresistance as well. We then use this generalized method to perform

S. Marianer; D. J. Bergman

1989-01-01

258

Vector Percolation Analysis of Triglyceride-based Thermoset Polymers  

NASA Astrophysics Data System (ADS)

Thermosetting Acrylated triglycerides (ATG) were prepared from various oils and model triglycerides. The distribution of acrylate groups was calculated from the distribution of unsaturation sites on unmodified oils, assuming a binomial distribution of acrylate groups. The ATG were both homopolymerized and copolymerized with styrene. The cross-link density v, of the polymers was calculated using the recursive method of Miller and Macosko from a knowledge of the acrylate distribution. The cross-link density was found to increase with the level of acrylation A, in a vector percolation manner, and the trends in the cross-link density predictions matched the experimental results. The deviation in the experimental results and model predictions were the result of intramolecular cross-linking. Approximately 0.5 and 0.8 acrylates per triglyceride were lost to intramolecular cyclization for homopolymerized acrylated triglycerides and triglycerides copolymerized with styrene, respectively. Equations for the level of perfection p, of the triglyceride networks and the percolation threshold pc, were developed using the calculated number of acrylates lost to cyclization. Polymers with p < 0.1 without styrene, and p < 0.39 with styrene did not have mechanical integrity, validating the definition of the level of perfection and percolation threshold pc. The tensile strength, S ˜ [p-p]^1/2 and modulus E ˜ [p-pc]^3 , were in accord with vector percolation theory, where p could be derived experimentally via A ˜ [p-pc] , v ˜ A and FTIR analysis of the extent of reaction of the C=C groups. These results also indicated how mechanical properties were controlled by the fatty acid distribution function of the plant oils, and which oil would give the best particular property. Supported by EPA and DoE.

Lascala, John J.; Wool, Richard P.

2003-03-01

259

Traveling time and traveling length in critical percolation clusters  

Microsoft Academic Search

We study traveling time and traveling length for tracer dispersion in two-dimensional bond percolation, modeling flow by tracer particles driven by a pressure difference between two points separated by Euclidean distance r. We find that the minimal traveling time tmin scales as tmin~r1.33, which is different from the scaling of the most probable traveling time, t~~r1.64. We also calculate the

Youngki Lee; José S. Andrade Jr.; Sergey V. Buldyrev; Nikolay V. Dokholyan; Shlomo Havlin; Peter R. King; Gerald Paul; H. Eugene Stanley

1999-01-01

260

Ammonia Saturation Constants for Predominant Species of Rumen Bacteria  

Microsoft Academic Search

Ammonia saturation constants were determined for representative pure cul- tures of predominant, anaerobic, ferment~ ative rumen bacteria. Based on growth experiments with ammonia limited continuous cultures, average estimates for ammonia saturation constants of Bac ~ teroides amylopbilus and Bacteroides rurninicola were 10.5 and 23.5 \\/IM ammonia-nitrogen, respectively. With ammonia-limited linear-growth cultures, the estimates for the ammonia saturation constants of B.

D. M. Schaefer; C. L. Davis; M. P. Bryant

1980-01-01

261

LARGE ENVIRONMENTAL CHAMBER: AMMONIA RECOVERY CALIBRATION  

Microsoft Academic Search

The ability to accurately measure ammonia emissions from farms is an important issue both in terms of establishing emissions regulations and for effective evaluation of mitigation techniques. To address this issue, experimental trials were carried out to determine the ability to quantitatively recover ammonia released within a large environmental chamber designed to house six dairy cows or manure processing technologies.

A. M. Lefcourt

262

Decontaminating Aluminum/Ammonia Heat Pipes  

NASA Technical Reports Server (NTRS)

Internal gas slugs reduced or eliminated. Manufacturing method increases efficiency of aluminum heat pipes in which ammonia is working fluid by insuring pipe filled with nearly pure charge of ammonia. In new process heat pipe initially closed with stainless-steel valve instead of weld so pipe put through several cycles of filling, purging, and accelerated aging.

Jones, J. A.

1985-01-01

263

Regeneration of ammonia borane from polyborazylene  

DOEpatents

Method of producing ammonia borane, comprising providing a reagent comprising a dehydrogenated material in a suitable solvent; and combining the reagent with a reducing agent comprising hydrazine, a hydrazine derivative, or combinations thereof, in a reaction which produces a mixture comprising ammonia borane.

Sutton, Andrew; Gordon, John C; Ott, Kevin C; Burrell, Anthony K

2013-02-05

264

Measuring ammonia from space: limits and possibilities  

NASA Astrophysics Data System (ADS)

Ammonia (NH3) is an important component in local, regional, and global tropospheric chemistry. Ammonia contributes significantly to several well-known environmental problems: excess deposition in terrestrial ecosystems can lead to soil acidification and loss of plant diversity, while in coastal ecosystems, it can cause eutrophication, algal blooms, and loss of fish and shellfish. In the atmosphere NH3 can combine with sulfates and nitric acid to form ammonium nitrate and ammonium sulfate, which constitute a substantial fraction of fine particulate matter (PM2.5). Nevertheless, there is great uncertainty in the magnitude and in the spatial/seasonal variability of ammonia concentrations and emissions. Retrievals of ammonia from spectra obtained from the Tropospheric Emission Spectrometer (TES) flying on the AURA satellite have the potential of significantly increasing our knowledge of the spatial and temporal variability of ammonia and of providing constraints on ammonia emissions through the use of inverse models at both the regional and global scales. We will present an updated evaluation of the TES ammonia retrievals using sensitivity studies, simulations, and in situ observations. We will demonstrate TES’ capability to discern spatial gradients and temporal variability in ammonia concentrations, with results from the TES transects over the Central Valley and North Carolina, as well as monthly means from TES global surveys. We will also show an example of using TES NH3 measurements to constrain surface emissions over North America.

Cady-Pereira, K. E.; Pinder, R. W.; Walker, J. T.; Bash, J. O.; Luo, M.; Henze, D. K.; Shephard, M. W.; Zhu, J.; Rinsland, C.

2010-12-01

265

Minerals Yearbook, 1992: Materials Recycling.  

National Technical Information Service (NTIS)

A large variety of materials are recycled by different sectors of our society. The materials recycling that is mainly addressed in this writing is from waste that is generated after manufacturing and use. Included is recycling that is generally more obvio...

A. O. Tanner

1992-01-01

266

Recycling Behavior: A Multidimensional Approach  

ERIC Educational Resources Information Center

This work centers on the study of consumer recycling roles to examine the sociodemographic and psychographic profile of the distribution of recycling tasks and roles within the household. With this aim in mind, an empirical work was carried out, the results of which suggest that recycling behavior is multidimensional and comprises the undertaking…

Meneses, Gonzalo Diaz; Palacio, Asuncion Beerli

2005-01-01

267

CHERRY: CHECKPOINTED EARLY RESOURCE RECYCLING  

E-print Network

1 2 3 CHERRY: CHECKPOINTED EARLY RESOURCE RECYCLING Jos´e F. Mart´inez1 , Jose Renau2 Michael C. Huang3 , Milos Prvulovic2 , and Josep Torrellas2 #12;Cherry: Checkpointed Early Resource Recycling efficient use by aggressive recycling Opportunity: Resources reserved until retirement § ¦ ¤ ¥ Solution

Torrellas, Josep

268

Percolation and cooperation with mobile agents: Geometric and strategy clusters  

NASA Astrophysics Data System (ADS)

We study the conditions for persistent cooperation in an off-lattice model of mobile agents playing the Prisoner's Dilemma game with pure, unconditional strategies. Each agent has an exclusion radius rP, which accounts for the population viscosity, and an interaction radius rint, which defines the instantaneous contact network for the game dynamics. We show that, differently from the rP=0 case, the model with finite-sized agents presents a coexistence phase with both cooperators and defectors, besides the two absorbing phases, in which either cooperators or defectors dominate. We provide, in addition, a geometric interpretation of the transitions between phases. In analogy with lattice models, the geometric percolation of the contact network (i.e., irrespective of the strategy) enhances cooperation. More importantly, we show that the percolation of defectors is an essential condition for their survival. Differently from compact clusters of cooperators, isolated groups of defectors will eventually become extinct if not percolating, independently of their size.

Vainstein, Mendeli H.; Brito, Carolina; Arenzon, Jeferson J.

2014-08-01

269

Double Percolation Phase Transition in Clustered Complex Networks  

NASA Astrophysics Data System (ADS)

The internal organization of complex networks often has striking consequences on either their response to external perturbations or on their dynamical properties. In addition to small-world and scale-free properties, clustering is the most common topological characteristic observed in many real networked systems. In this paper, we report an extensive numerical study on the effects of clustering on the structural properties of complex networks. Strong clustering in heterogeneous networks induces the emergence of a core-periphery organization that has a critical effect on the percolation properties of the networks. We observe a novel double phase transition with an intermediate phase in which only the core of the network is percolated and a final phase in which the periphery percolates regardless of the core. This result implies breaking of the same symmetry at two different values of the control parameter, in stark contrast to the modern theory of continuous phase transitions. Inspired by this core-periphery organization, we introduce a simple model that allows us to analytically prove that such an anomalous phase transition is, in fact, possible.

Colomer-de-Simón, Pol; Boguñá, Marián

2014-10-01

270

Percolation and cooperation with mobile agents: geometric and strategy clusters.  

PubMed

We study the conditions for persistent cooperation in an off-lattice model of mobile agents playing the Prisoner's Dilemma game with pure, unconditional strategies. Each agent has an exclusion radius r(P), which accounts for the population viscosity, and an interaction radius r(int), which defines the instantaneous contact network for the game dynamics. We show that, differently from the r(P)=0 case, the model with finite-sized agents presents a coexistence phase with both cooperators and defectors, besides the two absorbing phases, in which either cooperators or defectors dominate. We provide, in addition, a geometric interpretation of the transitions between phases. In analogy with lattice models, the geometric percolation of the contact network (i.e., irrespective of the strategy) enhances cooperation. More importantly, we show that the percolation of defectors is an essential condition for their survival. Differently from compact clusters of cooperators, isolated groups of defectors will eventually become extinct if not percolating, independently of their size. PMID:25215713

Vainstein, Mendeli H; Brito, Carolina; Arenzon, Jeferson J

2014-08-01

271

Loopless nontrapping invasion-percolation model for fracking  

NASA Astrophysics Data System (ADS)

Recent developments in hydraulic fracturing (fracking) have enabled the recovery of large quantities of natural gas and oil from old, low-permeability shales. These developments include a change from low-volume, high-viscosity fluid injection to high-volume, low-viscosity injection. The injected fluid introduces distributed damage that provides fracture permeability for the extraction of the gas and oil. In order to model this process, we utilize a loopless nontrapping invasion percolation previously introduced to model optimal polymers in a strongly disordered medium and for determining minimum energy spanning trees on a lattice. We performed numerical simulations on a two-dimensional square lattice and find significant differences from other percolation models. Additionally, we find that the growing fracture network satisfies both Horton-Strahler and Tokunaga network statistics. As with other invasion percolation models, our model displays burst dynamics, in which the cluster extends rapidly into a connected region. We introduce an alternative definition of bursts to be a consecutive series of opened bonds whose strengths are all below a specified value. Using this definition of bursts, we find good agreement with a power-law frequency-area distribution. These results are generally consistent with the observed distribution of microseismicity observed during a high-volume frack.

Norris, J. Quinn; Turcotte, Donald L.; Rundle, John B.

2014-02-01

272

Percolation and pore structure in mortars and concrete  

SciTech Connect

The cement paste in concrete and mortar has been shown to have a pore size distribution different than that of plain paste hydrated without aggregate. For mortar and concrete, additional porosity occurs in pore sizes larger than the plain paste`s threshold diameter as measured by mercury intrusion. Based on the assumption that these larger pores are essentially present only in the interfacial zones surrounding each aggregate, an experimental program was designed in which the volume fraction of sand in a mortar was varied in a systematic fashion and the resultant pore system probed using mercury intrusion porosimetry. The intrusion characteristics were observed to change drastically at a critical sand content. Similar results are observed for a series of mortar specimens in which the cement paste contains 10% silica fume. To better interpret the experimental results, a hard core/soft shell computer model has been developed to examine the percolation characteristics of these interfacial zone pores. Using the model, interfacial zone percolation in concretes is also examined. Finally, the implications of interfacial zone percolation for transport properties and durability of mortar and concrete are discussed.

Winslow, D.N.; Cohen, M.D. [Purdue Univ., West Lafayette, IN (United States). School of Civil Engineering] [Purdue Univ., West Lafayette, IN (United States). School of Civil Engineering; Bentz, D.P.; Snyder, K.A.; Garboczi, E.J. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)] [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1994-04-01

273

Emergent Percolation Length and Localization in Random Elastic Networks  

NASA Astrophysics Data System (ADS)

We study, theoretically and numerically, a minimal model for phonons in a disordered system. For sufficient disorder, the vibrational modes of this classical system can become Anderson localized, yet this problem has received significantly less attention than its electronic counterpart. We find rich behavior in the localization properties of the phonons as a function of the density, frequency, and spatial dimension. We use a percolation analysis to argue for a Debye spectrum at low frequencies for dimensions higher than one, and for a localization-delocalization transition (at a critical frequency) above two dimensions. We show that in contrast to the behavior in electronic systems, the transition exists for arbitrarily large disorder, albeit with an exponentially small critical frequency. The structure of the modes reflects a divergent percolation length that arises from the disorder in the springs without being explicitly present in the definition of our model. Within the percolation approach, we calculate the speed of sound of the delocalized modes (phonons), which we corroborate with numerics. We find the critical frequency of the localization transition at a given density and find good agreement of these predictions with numerical results using a recursive Green-function method that was adapted for this problem. The connection of our results to recent experiments on amorphous solids is discussed.

Amir, Ariel; Krich, Jacob J.; Vitelli, Vincenzo; Oreg, Yuval; Imry, Yoseph

2013-04-01

274

Heterogeneous-k-core versus Bootstrap Percolation on Complex Networks  

E-print Network

We introduce the heterogeneous-$k$-core, which generalizes the $k$-core, and contrast it with bootstrap percolation. Vertices have a threshold $k_i$ which may be different at each vertex. If a vertex has less than $k_i$ neighbors it is pruned from the network. The heterogeneous-$k$-core is the sub-graph remaining after no further vertices can be pruned. If the thresholds $k_i$ are $1$ with probability $f$ or $k \\geq 3$ with probability $(1-f)$, the process forms one branch of an activation-pruning process which demonstrates hysteresis. The other branch is formed by ordinary bootstrap percolation. We show that there are two types of transitions in this heterogeneous-$k$-core process: the giant heterogeneous-$k$-core may appear with a continuous transition and there may be a second, discontinuous, hybrid transition. We compare critical phenomena, critical clusters and avalanches at the heterogeneous-$k$-core and bootstrap percolation transitions. We also show that network structure has a crucial effect on these processes, with the giant heterogeneous-$k$-core appearing immediately at a finite value for any $f > 0$ when the degree distribution tends to a power law $P(q) \\sim q^{-\\gamma}$ with $\\gamma < 3$.

G. J. Baxter; S. N. Dorogovtsev; A. V. Goltsev; J. F. F. Mendes

2010-12-20

275

Theory of percolation and tunneling regimes in nanogranular metal films  

NASA Astrophysics Data System (ADS)

Nanogranular metal composites, consisting of immiscible metallic and insulating phases deposited on a substrate, are characterized by two distinct electronic transport regimes depending on the relative amount of the metallic phase. At sufficiently large metallic loadings, granular metals behave as percolating systems with a well-defined critical concentration above which macroscopic clusters of physically connected conductive particles span the entire sample. Below the critical loading, granular metal films are in the dielectric regime, where current can flow throughout the composite only via hopping or tunneling processes between isolated nanosized particles or clusters. In this case transport is intrinsically nonpercolative in the sense that no critical concentration can be identified for the onset of transport. It is shown here that, although being very different in nature, these two regimes can be described by treating percolation and hopping on equal footing. By considering general features of the microstructure and of the electrical connectedness, the concentration dependence of the dc conductivity of several nanogranular metal films is reproduced to high accuracy within an effective-medium approach. In particular, fits to published experimental data enable us to extract the values of microscopic parameters that govern the percolation and tunneling regimes, explaining thus the transport properties observed in nanogranular metal films.

Grimaldi, Claudio

2014-06-01

276

The Fermi paradox: An approach based on percolation theory  

NASA Technical Reports Server (NTRS)

If even a very small fraction of the hundred billion stars in the galaxy are home to technological civilizations which colonize over interstellar distances, the entire galaxy could be completely colonized in a few million years. The absence of such extraterrestrial civilizations visiting Earth is the Fermi paradox. A model for interstellar colonization is proposed using the assumption that there is a maximum distance over which direct interstellar colonization is feasible. Due to the time lag involved in interstellar communications, it is assumed that an interstellar colony will rapidly develop a culture independent of the civilization that originally settled it. Any given colony will have a probability P of developing a colonizing civilization, and a probability (1-P) that it will develop a non-colonizing civilization. These assumptions lead to the colonization of the galaxy occuring as a percolation problem. In a percolation problem, there will be a critical value of percolation probability, P(sub c). For P less than P(sub c), colonization will always terminate after a finite number of colonies. Growth will occur in 'clusters', with the outside of each cluster consisting of non-colonizing civilizations. For P greater than P(sub c), small uncolonized voids will exist, bounded by non-colonizing civilizations. For P approximately = to P(sub c), arbitrarily large filled regions exist, and also arbitrarily large empty regions.

Landis, Geoffrey A.

1993-01-01

277

Fuels from Recycling Systems  

ERIC Educational Resources Information Center

Three systems, operating at sufficient scale, produce fuels that may be alternatives to oil and gas. These three recycling systems are: Black Clawson Fiberclaim, Franklin, Ohio; Union Carbide, South Charleston, West Virginia; and Union Electric, St. Louis, Missouri. These produce a wet fuel, a pyrolytic gas, and a dry fuel, respectively. (BT)

Tillman, David A.

1975-01-01

278

Recycle Your Own Paper!  

NSDL National Science Digital Library

In this activity (page 2 of PDF), learners will prepare sheets of homemade recycled paper from several different source pulps. Once dry, each sample will be drawn on with a marker to test how far ink spreads in the fibers of the different kinds of papers. Relates to the linked video, DragonflyTV GPS: Garbology.

Twin Cities Public Television, Inc.

2007-01-01

279

Helium-Recycling Plant  

NASA Technical Reports Server (NTRS)

Proposed system recovers and stores helium gas for reuse. Maintains helium at 99.99-percent purity, preventing water vapor from atmosphere or lubricating oil from pumps from contaminating gas. System takes in gas at nearly constant low back pressure near atmospheric pressure; introduces little or no back pressure into source of helium. Concept also extended to recycling of other gases.

Cook, Joseph

1996-01-01

280

Recycling Study Guide.  

ERIC Educational Resources Information Center

This study guide was designed to help teachers and students understand the problems surrounding solid wastes. It includes an overview of solid waste and recycling, a glossary, suggested activities and a list of resource publications, audiovisual materials and organizations. There are 19 activity suggestions included in this guide designed for use…

Hallowell, Anne; And Others

281

The Recycle Team.  

ERIC Educational Resources Information Center

This guide provides lessons that enable students to learn how important it is for each of us to take care of the environment by minimizing the problems caused by too much trash. In the 10 lessons included here, students and their families learn how they can be part of the solution by practicing source reduction and by reusing, recycling, and…

Scott, Roger; And Others

282

Glass recycling and reuse  

Microsoft Academic Search

Methods are surveyed for recycling and\\/or reusing post-consumer glass products to determine which methods are most favorable. The following topics are included: the properties of glass, glass manufacture; analyses of alternatives to direct disposal of glass products; reuse of waste glass for glass manufacture; techniques for the separation of glass from municipal refuse; the development of degradable glass containers; returnable

H. R. Samtur

1974-01-01

283

Recycling and Restoration  

NSDL National Science Digital Library

This video explains how Bernheim Arboretum and Research Forest near Louisville, Kentucky used recycled cypress from pickle vats to build its visitor center and then “paid back” nature by creating a cypress-tupelo swamp at one end of a lake on the park grounds.

Ket

2011-01-11

284

Reduce, Reuse, and Recycle  

NSDL National Science Digital Library

Boys and girls, grab your nose-plugs because today we are going to be digging through some garbage! We use a lot of garbage; the average American throws away nearly four pounds everyday. That\\'s a whopping 1,600 pounds a year! That means that every year, EACH one of you toss enough trash to equal the weight of all the students in our class...COMBINED! That\\'s a lot of garbage. Our world is big, but you might not have realized just how small it really is when it comes to holding all this trash. Would you want garbage in your backyard? Your playground? The park? There\\'s only so many places to store our waste. So, what do we do? We RECYCLE! What Does It Mean To Recycle? Recycling is taking things we use and would normally through into the trash can and putting them in a separate container. Instead of going to the dump, it goes to a recycling plant. Things like paper, newspaper, cardboard, plastic, glass, and aluminum are all products ...

Nicole

2008-11-19

285

Computer Recycling Farm USA  

USGS Multimedia Gallery

USGS conducted a study of plastic pollution at this rural US site in the Midwest.  The recycler was receiving computers from companies at a rate which greatly exceeded the capacity of the operation.  Approximately 50,000 computers remained outdoors on 15 acres for nearly a decade.  The site has sinc...

2010-08-13

286

Study of an ammonia-based wet scrubbing process in a continuous flow system  

SciTech Connect

A continuous gas and liquid flow, regenerative scrubbing process for CO{sub 2} capture was demonstrated at the bench-scale level. An aqueous ammonia-based solution captures CO{sub 2} from simulated flue gas in an absorber and releases a nearly pure stream of CO{sub 2} in the regenerator. After the regeneration, the solution of ammonium compounds is recycled to the absorber. The design of a continuous flow unit was based on earlier exploratory results from a semi-batch reactor, where a CO{sub 2} and N{sub 2} simulated flue gas mixture flowed through a well-mixed batch of ammonia-based solution. During the semi-batch tests, the solution was cycled between absorption and regeneration steps to measure the carrying capacity of the solution at various initial ammonia concentrations and temperatures. Consequentially, a series of tests were conducted on the continuous unit to observe the effect of various parameters on CO{sub 2} removal efficiency and regenerator effectiveness within the flow system. The parameters that were studied included absorber temperature, regenerator temperature, initial NH{sub 3} concentration, simulated flue gas flow rate, liquid solvent inventory in the flow system, and height of the packed-bed absorber. From this testing and subsequent testing, ammonia losses from both the absorption and regeneration steps were quantified, and attempts were made to maintain steady state during operations. Implications of experimental results with respect to process design are discussed.

Mao, James X.; Lee, Anita S.; Kitchin, John R.; Nulwala, Hunaid B.; Luebke, David R.; Damodaran, Krishnan

2013-01-01

287

Regeneration of ammonia borane spent fuel  

SciTech Connect

A necessary target in realizing a hydrogen (H{sub 2}) economy, especially for the transportation sector, is its storage for controlled delivery, presumably to an energy producing fuel cell. In this vein, the U.S. Department of Energy's Centers of Excellence (CoE) in Hydrogen Storage have pursued different methodologies, including metal hydrides, chemical hydrides, and sorbents, for the expressed purpose of supplanting gasoline's current > 300 mile driving range. Chemical H{sub 2} storage has been dominated by one appealing material, ammonia borane (H{sub 3}N-BH{sub 3}, AB), due to its high gravimetric capacity of H{sub 2} (19.6 wt %) and low molecular weight (30.7 g mol{sup -1}). In addition, AB has both hydridic and protic moieties, yielding a material from which H{sub 2} can be readily released in contrast to the loss of H{sub 2} from C{sub 2}H{sub 6} which is substantially endothermic. As such, a number of publications have described H{sub 2} release from amine boranes, yielding various rates depending on the method applied. The viability of any chemical H{sub 2} storage system is critically dependent on efficient recyclability, but reports on the latter subject are sparse, invoke the use of high energy reducing agents, and suffer from low yields. Our group is currently engaged in trying to find and fully demonstrate an energy efficient regeneration process for the spent fuel from H{sub 2} depleted AB with a minimum number of steps. Although spent fuel composition depends on the dehydrogenation method, we have focused our efforts on the spent fuel resulting from metal-based catalysis, which has thus far shown the most promise. Metal-based catalysts have produced the fastest rates for a single equivalent of H{sub 2} released from AB and up to 2.5 equiv. of H{sub 2} can be produced within 2 hours. While ongoing work is being carried out to tailor the composition of spent AB fuel, a method has been developed for regenerating the predominant product, polyborazylene (PB) which can be obtained readily from the decomposition of borazine or from nickel carbene catalyst dehydrogenation. In this cycle, the PB is digested with benzenedithiol to yield two products which can both be converted to AB using Bu{sub 3}SnH and BU{sub 2}SnH{sub 2} as reductants. However, in a real world situation the process becomes more complicated for several reasons. Bu{sub 2}SnH{sub 2} is thermally unstable and therefore not viable in a process scale operation. This has led to the development of Bu{sub 3}SnH as the sole reductant although this requires an additional amine exchange step in order to facilitate the reduction to an amine-borane which can then be converted to AB. The tin by-products also need to be recycled in order to maximize the overall energy efficiency and therefore minimize the overall cost of the process. In addition, on an industrial scale, the mass of the tin reductant generates significant cost due to the manipulation of the relatively large quantities involved so reducing the mass at this stage would be of vast significance. We will discuss further developments made to the tin recycle component of the cycle (including methods to minimize tin usage) and investigate new methods of reduction of the digested products, primarily focusing on lighter reductants, including lighter analogs of Bu{sub 2}SnH{sub 2} and Bu{sub 3}SnH. These advances will have a significant impact on the cost of production and therefore the viability of AB as a fuel. Minimization of tin reagents and their recycle will contribute to reduction of the overall cost of AB regeneration and all stages of AB regeneration have been demonstrated.

Sutton, Andrew David [Los Alamos National Laboratory; Davis, Benjamin L [Los Alamos National Laboratory; Gordon, John C [Los Alamos National Laboratory

2009-01-01

288

Low-cost anodes for ammonia electrooxidation  

NASA Astrophysics Data System (ADS)

This research focused on the development of low-cost electrodes for the electrochemical oxidation of ammonia to nitrogen, a reaction that has possible applications in hydrogen generation, direct ammonia fuel cells, water treatment, and sensors. Statistical design of experiments was used to help develop an efficient and scalable process for electrodeposition of platinum with a specific electrochemical surface area of over 25 m2 /g. Catalyst surface area and activity were evaluated using cyclic voltammetry, and the material microstructure and morphology were investigated using x-ray diffraction and scanning electron microscopy. The synthesized electrodes were found to be active toward the ammonia electrooxidation reaction, particularly when supporting electrolyte was added. However, supporting electrolyte was not required in order to oxidize the ammonia. As proof of concept, a homemade direct ammonia fuel cell employing a commercial anion exchange membrane was tested at room temperature with gravity-fed fuel and without supporting electrolyte. At room temperature, with passive reactant supply and using dissolved oxygen at the cathode, the cell produced about one quarter the power of a direct methanol fuel cell that used active transport of humidified oxygen and preheated (50 °C) methanol. With continued development of the membrane, cathode and membrane electrode assembly, the passive direct ammonia fuel cell using anion exchange membrane could have performance similar to the equivalent direct methanol fuel cell, and it could benefit from many advantages of ammonia over methanol such as lower cost, higher energy density, and reduced greenhouse gas emissions.

Selverston, Steven M.

289

The Ammonia Freeze Explosion (AFEX) process  

SciTech Connect

The Ammonia Freeze Explosion (AFEX) process treats lignocellulose with high-pressure liquid ammonia, and then explosively releases the pressure. The combined chemical effect (cellulose decrystallization) and physical effect (increased accessible surface area) dramatically increase lignocellulose susceptibility to enzymatic attack. There are many adjustable parameters in the AFEX process: ammonia loading, water loading, temperature, time, blowdown pressure, and number of treatments. The effect of these parameters on enzymatic susceptibility was explored for three materials: Coastal bermudagrass, bagasse, and newspaper. Nearly quantitative sugar yields were demonstrated for Coastal bermudagrass and bagasse, using a very low enzyme loading (5 IU/g). Newspaper proved to be much more resistant to enzymatic hydrolysis.

Holtzapple, M.T.; Jae-Hoon Jun; Ganesh Ashok; Patibandla, S.L.; Dale, B.E. [Texas A& M Univ., College Station, TX (United States)

1991-12-31

290

Densification-induced conductivity percolation in high-porosity pharmaceutical microcrystalline cellulose compacts  

NASA Astrophysics Data System (ADS)

The percolation theory is established as a useful tool in the field of pharmaceutical materials science. It is shown that percolation theory, developed for analyzing insulator-conductor transitions, can be applied to describe imperfect dc conduction in pharmaceutical microcrystalline cellulose during densification. The system, in fact, exactly reproduces the values of the percolation threshold and exponent estimated for a three-dimensional random continuum. Our data clearly show a crossover from a power-law percolation theory region to a linear effective medium theory region at a cellulose porosity of ˜0.7.

Strømme, M.; Niklasson, G. A.; Ek, R.

2003-01-01

291

Site-bond percolation on triangular lattices: Monte Carlo simulation and analytical approach  

NASA Astrophysics Data System (ADS)

A generalization of the pure site and pure bond percolation problems called site-bond percolation on a triangular lattice is studied. Motivated by considerations of cluster connectivity, two distinct schemes (denoted as S?B and S?B) for site-bond percolation are used. In S?B (S?B), two points are said to be connected if a sequence of occupied sites and (or) bonds joins them. By using finite-size scaling theory, data from S?B and S?B are analyzed in order to determine (i) the phase boundary between the percolating and non-percolating regions and (ii) the numerical values of the critical exponents of the phase transition occurring in the system. A theoretical approach, based on exact calculations of configurations on finite triangular cells, is applied to study the site-bond percolation on triangular lattices. The percolation processes have been monitored by following the percolation function, defined as the ratio between the number of percolating configurations and the total number of available configurations for a given cell size and concentration of occupied elements. A comparison of the results obtained by these two methods has been performed and discussed.

González, M. I.; Centres, P.; Lebrecht, W.; Ramirez-Pastor, A. J.; Nieto, F.

2013-12-01

292

Municipal solid waste recycling issues  

SciTech Connect

Municipal solid waste (MSW) recycling targets have been set nationally and in many states. Unfortunately, the definitions of recycling, rates of recycling, and the appropriate components of MSW vary. MSW recycling has been found to be costly for most municipalities compared to landfill disposal. MSW recycling policy should be determined by the cost to the community and to society more generally. In particular, recycling is a good policy only if environmental impacts and the resources used to collect, sort, and recycle a material are less than the environmental impacts and resources needed to provide equivalent virgin material plus the resources needed to dispose of the postconsumer material safely. From a review of the existing economic experience with recycling and an analysis of the environmental benefits (including estimation of external social costs), the authors find that, for most communities, curbside recycling is only justifiable for some postconsumer waste, such as aluminum and other metals. They argue that alternatives to curbside recycling collection should be explored, including product takeback for products with a toxic content (such as batteries) or product redesign to permit more effective product remanufacture.

Lave, L.B.; Hendrickson, C.T.; Conway-Schempf, N.M.; McMichael, F.C. [Carnegie-Mellon Univ., Pittsburgh, PA (United States)] [Carnegie-Mellon Univ., Pittsburgh, PA (United States)

1999-10-01

293

Prevention of Ammonia and Glutamate Neurotoxicity by Carnitine: Molecular Mechanisms  

Microsoft Academic Search

Carnitine has beneficial effects in different pathologies and prevents acute ammonia toxicity (ammonia-induced death of animals). Acute ammonia toxicity is mediated by excessive activation of the NMDA-type of glutamate receptors, which mediates glutamate neurotoxicity. We showed that carnitine prevents glutamate neurotoxicity in primary cultures of cerebellar neurons. This supports the idea that the protective effect of carnitine against ammonia toxicity

Marta Llansola; Slaven Erceg; Mariluz Hernández-Viadel; Vicente Felipo

2002-01-01

294

AMMONIA EFFECTS ON MICROINVERTEBRATES AND FISH IN OUTDOOR EXPERIMENTAL STREAMS  

EPA Science Inventory

Laboratory data on ammonia effects, the US EPA national water quality criteria for ammonia, and ammonia site-specific criteria were evaluated in four outdoor experimental streams (one control and three treatment streams) over a 76-week period. Calculated un-ionized ammonia concen...

295

Architecture of idiotypic networks: Percolation and scaling Behavior  

NASA Astrophysics Data System (ADS)

We investigate a model where idiotypes (characterizing B lymphocytes and antibodies of an immune system) and anti-idiotypes are represented by complementary bit strings of a given length d allowing for a number of mismatches (matching rules). In this model, the vertices of the hypercube in dimension d represent the potential repertoire of idiotypes. A random set of (with probability p) occupied vertices corresponds to the expressed repertoire of idiotypes at a given moment. Vertices of this set linked by the above matching rules build random clusters. We give a structural and statistical characterization of these clusters, or in other words of the architecture of the idiotypic network. Increasing the probability p one finds at a critical p a percolation transition where for the first time a large connected graph occurs with probability 1. Increasing p further, there is a second transition above which the repertoire is complete in the sense that any newly introduced idiotype finds a complementary anti-idiotype. We introduce structural characteristics such as the mass distribution and the fragmentation rate for random clusters, and determine the scaling behavior of the cluster size distribution near the percolation transition, including finite size corrections. We find that slightly above the percolation transition the large connected cluster (the central part of the idiotypic network) consists typically of one highly connected part and a number of weakly connected constituents and coexists with a number of small, isolated clusters. This is in accordance with the picture of a central and a peripheral part of the idiotypic network and gives some support to idealized architectures of the central part used in recent dynamical mean field models.

Brede, Markus; Behn, Ulrich

2001-07-01

296

Serpentinization of sintered olivine during seawater percolation experiments  

NASA Astrophysics Data System (ADS)

Hydration of the mantle lithosphere exposed along detachment faults at slow-spreading ridges leads to strong modification of rock rheological, geophysical and geochemical properties, and to the emission of large amounts of H2 and CH4, and of complex carbon molecules that support primitive ecosystems. The sustainability and efficiency of this hydration process, serpentinisation, and of associated reactions, requires penetration and renewal of fluids at the mineral-fluid interface. However, precipitation of material along flow paths will affect porosity and permeability that, in turn, will have feedbacks effects on the reactions. It is thus necessary to investigate the sustainability of flow paths, and the evolution of reaction rates for a dynamic system under representative conditions. We investigate these processes by percolation experiments carried out under P, T representative conditions, using the ICARE Microlab experimental bench. We present the preliminary results of seawater percolation within samples of sintered San Carlos olivine. The experiments were carried out under a confined pressure of 190 bars and a temperature of 190° C and water flow was set at a constant specific discharge of 0.06 ml/h.. The experiments were performed at very slow flow rate to be more representative of natural systems. ICARE Microlab allows measuring continuously the permeability changes during the percolation experiment and sampling the brine at the outlet of the sample. After 20 days of experiments, poorly crystallized serpentine and iron oxide formed within the micro-cracks while permeability strongly decreases. Such rapid precipitation of serpentine results in clogging of fluid paths. The chemical composition of the outlet fluid is dominated by Si and is depleted in Mg relative to stoechiometric dissolution of olivine during the whole experiment suggesting that brucite possibly formed. SEM and AEM/TEM are used to characterize the reactive interfaces and the neoformed materials.

Luquot, Linda; Andreani, Muriel; Godard, Marguerite; Gouze, Philippe; Gibert, Benoit

2010-05-01

297

Statistics of rocky coast erosion and percolation theory  

NASA Astrophysics Data System (ADS)

The dynamics of rocky coasts is an erratic phenomenon featuring numerous small erosion events, but sometimes large dramatic collapses. In this sense, its study should not limit or rely on average erosion rates. Recent studies, based on historical as well as recent data, have indicated that the frequency of magnitude of erosion events display long tail distribution, similar to what observed in landslide. In other words the time evolution of a coast morphology does not enter the classical category of Gaussian process, but rather that of critical systems in physics. We recently proposed a minimal dynamical model of rocky coast erosion which is able to reproduce the diversity of rocky coast morphologies and their dynamics. This model is based on a single, simple ingredient, the retroaction of the coast morphology on the erosive power of the sea. It follows from the idea that erosion can spontaneously create irregular seashores, but, in turn, the geometrical irregularity of the coast participates to the damping of sea-waves, decreasing the average wave amplitude and erosive power. The resulting mutual self-stabilization dynamics of the sea erosion power and coastal irregular morphology leads spontaneously the system to a critical dynamics. Our results indicate then that rocky coast erosion and the statistical theory of percolation are closely related. In this framework, the sometimes fractal geometry of coastlines can be recovered and understood in terms of fractal dimension of the external perimeter of a percolation cluster. From a more practical point of view, the analogy with percolation interfaces means that the coast constitutes a strong, but possibly fragile, barrier to sea erosion, emerging from a self-organised selection process. Accordingly, the effect of a slow weathering degradation of the rocks mechanical properties, as well as other perturbations from natural or human cause, can trigger random and large erosion events difficult to predict and control. To the extent that these ideas apply, natural coasts should be "preserved" and managed with care.

Baldassarri, A.; Sapoval, B.

2012-04-01

298

Ammonia volatilization after injection of anhydrous ammonia into arable soils of different moisture levels  

Microsoft Academic Search

Laboratory experiments have shown appreciable losses of ammonia after injection of anhydrous ammonia into dry and wet soils.\\u000a In this study losses of ammonia injected into a moist (tension 10 kPa), dry (tension 160 kPa) and a wet (tension 1.6 kPa)\\u000a sandy loam were measured under field conditions using wind tunnels. Losses were insignificant from a moist soil. However losses

S. G. Sommer; B. T. Christensen

1992-01-01

299

A novel invasion percolation model for co-interpenetrating composites  

NASA Astrophysics Data System (ADS)

A novel Invasion Percolation model for simulating the reactive metal infiltration of ceramics to form a co-interpenetrating composite is presented. By combining the pore-level dynamics of percolation models with kinetic Monte Carlo methods for simulating surface phase transformation it is possible to simulate both thermodynamic driving forces for infiltration: the applied pressure and the reactive wetting process. In doing so the model describes both the capillary fingering effects that dominate at high pressures and the time evolution of reaction byproduct phases that cause pore space closure at high temperature. At very high temperature and/or low pressure a "core-shell" morphology forms. At very high pressures the assumption of quasi-static flow in discrete pore throats is violated, and viscous channel flow occurs that leaves undesirable levels of residual porosity. Statistics derived from percolation theory were applied to determine the effective percolation threshold pressure for infiltration and the critical pressure for divergence of the fingerwidth. At pressure intermediate between these two extremes the residual Pore size distribution was found to determine the probability of discrete pore cluster occurrence, which served as a means, in addition to fingerwidth, for quantifying microstructures. This enabled the application of Weibull statistics to determine the 98% probability survival strength and the Weibull shape factor. For analyzing mechanical properties, the pore cluster probability is a better measurement. For analysis of thermal properties, the fingerwidth' should be used. The adjustable parameters experimented with were the transformation rate, initial transformation contact angle, applied pressure, kinetic growth rate constant, and initial matrix porosity. The Aluminum/Silicon Carbide system was chosen first because of the large volume of wetting data available, but the model is designed to simulate any system were reactive wetting data, kinetic growth rate data, and correlation of surface XRD data with temperature are available. In general, the conditions most favorable for the formation of the most interconnected composites were high transformation rate, low to intermediate pressure, low initial transformation contact angle (low temperature), low kinetic growth rate constant, and low initial matrix porosity. The optimal combinations were presented in the form of Weibull survival probability plots and process maps.

Perham, Timothy James

2000-10-01

300

On the genre-fication of music: a percolation approach  

NASA Astrophysics Data System (ADS)

We analyze web-downloaded data on people sharing their music library. By attributing to each music group usual music genres (Rock, Pop ...), and analysing correlations between music groups of different genres with percolation-idea based methods, we probe the reality of these subdivisions and construct a music genre cartography, with a tree representation. We also discuss an alternative objective way to classify music, that is based on the complex structure of the groups audience. Finally, a link is drawn with the theory of hidden variables in complex networks.

Lambiotte, R.; Ausloos, M.

2006-03-01

301

Empires and percolation: stochastic merging of adjacent regions  

NASA Astrophysics Data System (ADS)

We introduce a stochastic model in which adjacent planar regions A, B merge stochastically at some rate ?(A, B) and observe analogies with the well-studied topics of mean-field coagulation and of bond percolation. Do infinite regions appear in finite time? We give a simple condition on ? for this hegemony property to hold, and another simple condition for it to not hold, but there is a large gap between these conditions, which includes the case ?(A, B) ? 1. For this case, a non-rigorous analytic argument and simulations suggest hegemony.

Aldous, D. J.; Ong, J. R.; Zhou, W.

2010-01-01

302

Levitation and percolation in quantum Hall systems with correlated disorder  

NASA Astrophysics Data System (ADS)

We investigate the integer quantum Hall system in a two dimensional lattice model with spatially correlated disorder by using the efficient method to calculate the Chern number proposed by Fukui [J. Phys. Soc. Jpn. 74, 1674 (2005)]. Distribution of charge density indicates that the extended states at the center of each Landau band have percolating current paths, which are topologically equivalent to the edge states that exist in a system with boundaries. As increasing the strength of disorder, the floating feature is observed in an averaged Hall conductance as a function of filling factor. Its relation to the observed experiments is also discussed.

Song, Hui; Maruyama, Isao; Hatsugai, Yasuhiro

2007-10-01

303

Validation of the tunneling percolation staircase model in granular metals  

NASA Astrophysics Data System (ADS)

In this Letter, we provide conclusive evidence for a lattice like arrangement of the silver grains in the nanogranular Ag-Al2O3 metal. The evidence for the presence of clearly separated first and second near neighbor grains was derived from the electrical conductivity dependence on the metallic content in these composites. The data were analyzed in light of the tunneling percolation staircase model that we have recently suggested for lattices or systems with discrete well-defined interparticle distances in the continuum.

Balberg, I.; Azulay, D.; Jedrzejewski, J.; Savir, E.

2014-06-01

304

Pathogen Mutation Modeled by Competition Between Site and Bond Percolation  

NASA Astrophysics Data System (ADS)

While disease propagation is a main focus of network science, its coevolution with treatment has yet to be studied in this framework. We present a mean-field and stochastic analysis of an epidemic model with antiviral administration and resistance development. We show how this model maps to a coevolutive competition between site and bond percolation featuring hysteresis and both second- and first-order phase transitions. The latter, whose existence on networks is a long-standing question, imply that a microscopic change in infection rate can lead to macroscopic jumps in expected epidemic size.

Hébert-Dufresne, Laurent; Patterson-Lomba, Oscar; Goerg, Georg M.; Althouse, Benjamin M.

2013-03-01

305

Understanding recycling behavior in Kentucky: Who recycles and why  

NASA Astrophysics Data System (ADS)

Recycling behavior and the motivations behind recycling are being analyzed in a collaborative study between the Sloan Industry Center for a Sustainable Aluminum Industry, the Center for Aluminum Technology, Secat, and the Gatton College of Business and Economics at the University of Kentucky in Lexington. The goals of this study are to determine why people recycle and to find ways to motivate people to recycle more, using Fayette County, Kentucky, as a sample study. It is hoped that the information gathered through educational and motivational efforts in this county can be used on a larger scale in communities throughout the United States.

Morgan, Fred W.; Hughes, Margaret V.

2006-08-01

306

Ammonia measurement with a pH electrode in the ammonia/urea-SCR process  

NASA Astrophysics Data System (ADS)

The selective catalytic reduction of nitrogen oxides with ammonia (ammonia SCR) and urea (urea SCR), respectively, is a widespread process to clean flue and diesel exhaust gases due to its simplicity and efficiency. The main challenge of the process is to minimize the ammonia emissions downstream of the SCR catalyst. We found that ammonia emissions of >10 ppm can reliably be detected with a simple pH electrode in the presence of CO2, SOx, NOx, and moderately weak organic acids. 10-20 ppm of ammonia in the exhaust gas are sufficient to neutralize the acids and to increase the pH value from 3 to 6. On this basis a continuous measuring method for ammonia was developed, which was used to control the dosage of urea in the SCR process. While keeping the ammonia emissions after the SCR catalyst at 5-30 ppm an average NOx removal efficiency (DeNOx) of >95% were achieved at a diesel test rig. The method can also be applied for exhaust gases with higher acid contents, if a basic pre-filter is added adsorbing the acidic exhaust components. Compared to water as absorption solution, more precise ammonia measurements are possible, if a 0.1 M NH4Cl absorption solution is applied, whose pH value is changing as a Nernst function of the ammonia concentration.

Kröcher, Oliver; Elsener, Martin

2007-03-01

307

Development and Selection of Ammonia Emission Factors.  

National Technical Information Service (NTIS)

This report compiles recent literature on ammonia (NH3) emission factors for application in the United States. Most of the recent research supports acid deposition studies in the European community (specifically, the Netherlands, Great Britain, and Scandi...

R. Battye, W. Battye, C. Overcash, S. Fudge

1994-01-01

308

DEVELOPMENT AND SELECTION OF AMMONIA EMISSION FACTORS  

EPA Science Inventory

This report compiles recent literature on ammonia (NH') emission factors for application in the United States. ost of the recent research supports acid deposition studies in the European community (specifically, the Netherlands, Great Britain, and Scandinavia) but some research h...

309

Ammonia volatilization in soil treated with tannery sludge.  

PubMed

The utilization of tannery sludge in agricultural areas can be an alternative for its disposal and recycling. Despite this procedure may cause the loss of nitrogen by ammonia volatilization, there is no information about this process in tropical soils. For two years a field experiment was carried out in Rolândia (Paraná State, Brazil), to evaluate the amount of NH(3) volatilization due to tannery sludge application on agricultural soil. The doses of total N applied varied from zero to 1200 kg ha(-1), maintained at the surface for 89 days, as usual in this region. The alkalinity of the tannery sludge used was equivalent to between 262 and 361 g CaCO(3) per kg. Michaelis-Menten equation was adequate to estimate NH(3)-N volatilization kinetics. The relation between total nitrogen applied as tannery sludge and the potentially volatilized NH(3)-N, calculated by the chemical-kinetics equation resulted in an average determination coefficient of 0.87 (P>0.01). In this period, the amount of volatilized NH(3) was more intense during the first 30 days; the time to reach half of the maximum NH(3) volatilization (K(m)) was 13 an 9 days for the first and second experiments, respectively. The total loss as ammonia in the whole period corresponded in average to 17.5% of the total N applied and to 35% of the NH(4)(+)-N present in the sludge. If tannery sludge is to be surface applied to supply N for crops, the amounts lost as NH(3) must be taken into consideration. PMID:20171093

Martines, A M; Nogueira, M A; Santos, C A; Nakatani, A S; Andrade, C A; Coscione, A R; Cantarella, H; Sousa, J P; Cardoso, E J B N

2010-06-01

310

Sugar-Driven Prebiotic Synthesis of Ammonia from Nitrite  

NASA Astrophysics Data System (ADS)

Reaction of 3-5 carbon sugars, glycolaldehyde, and ?-ketoaldehydes with nitrite under mild anaerobic aqueous conditions yielded ammonia, an essential substrate for the synthesis of nitrogen-containing molecules during abiogenesis. Under the same conditions, ammonia synthesis was not driven by formaldehyde, glyoxylate, 2-deoxyribose, and glucose, a result indicating that the reduction process requires an organic reductant containing either an accessible ?-hydroxycarbonyl group or an ?-dicarbonyl group. Small amounts of aqueous Fe+3 catalyzed the sugar-driven synthesis of ammonia. The glyceraldehyde concentration dependence of ammonia synthesis, and control studies of ammonia’s reaction with glyceraldehyde, indicated that ammonia formation is accompanied by incorporation of part of the synthesized ammonia into sugar-derived organic products. The ability of sugars to drive the synthesis of ammonia is considered important to abiogenesis because it provides a way to generate photochemically unstable ammonia at sites of sugar-based origin-of-life processes from nitrite, a plausible prebiotic nitrogen species.

Weber, Arthur L.

2010-03-01

311

Supercritical ammonia pretreatment of lignocellulosic materials  

SciTech Connect

A pretreatment technique using ammonia in a supercritical or near-critical fluid state was shown to substantially enhance the susceptibility of polysaccharides in lignocellulosics to subsequent hydrolysis by Trichoderma reesei cellulase. Near-theoretical conversion of cellulose and 70-80% conversion of hemicellulose to sugars from supercritical ammonia pretreated hardwoods or agricultural byproducts were obtained with a small dosage of cellulase. This technique was less effective toward softwoods. The pretreatment results are discussed in light of the properties of supercritical fluids.

Chou, Y.C.T.; Scott, C.D. (ed.)

1986-01-01

312

Corrosion inhibitor for aqueous ammonia absorption system  

DOEpatents

A method is described for inhibiting corrosion and the formation of hydrogen and thus improving absorption in an ammonia/water absorption refrigeration, air conditioning or heat pump system by maintaining the hydroxyl ion concentration of the aqueous ammonia working fluid within a selected range under anaerobic conditions at temperatures up to 425 F. This hydroxyl ion concentration is maintained by introducing to the aqueous ammonia working fluid an inhibitor in an amount effective to produce a hydroxyl ion concentration corresponding to a normality of the inhibitor relative to the water content ranging from about 0.015 N to about 0.2 N at 25 C. Also, working fluids for inhibiting the corrosion of carbon steel and resulting hydrogen formation and improving absorption in an ammonia/water absorption system under anaerobic conditions at up to 425 F. The working fluids may be aqueous solutions of ammonia and a strong base or aqueous solutions of ammonia, a strong base, and a specified buffer. 5 figs.

Phillips, B.A.; Whitlow, E.P.

1998-09-22

313

Recycling Bin Guide Locations and prices  

E-print Network

Recycling Bin Guide Locations and prices Metal Bins Deskside Bins with Side Saddle Rubbermaid Bins.58 for auxiliaries. And Non-Public Areas Public Offices Non-Public Recyclables Recyclables RecyclablesTrash Trash Trash #12;New Recycling Bin Guidelines Frequently Asked Questions (as of December 2008) · Why

Kirschner, Denise

314

Short-range correlations in percolation at criticality  

NASA Astrophysics Data System (ADS)

We derive the critical nearest-neighbor connectivity gn as 3/4, 3(7-9pctri)/4(5-4pctri), and 3(2+7pctri)/4(5-pctri) for bond percolation on the square, honeycomb, and triangular lattice, respectively, where pctri=2sin(?/18) is the percolation threshold for the triangular lattice, and confirm these values via Monte Carlo simulations. On the square lattice, we also numerically determine the critical next-nearest-neighbor connectivity as gnn=0.6875000(2), which confirms a conjecture by Mitra and Nienhuis [J. Stat. Mech. (2004) P10006, 10.1088/1742-5468/2004/10/P10006], implying the exact value gnn=11/16. We also determine the connectivity on a free surface as gnsurf=0.6250001(13) and conjecture that this value is exactly equal to 5/8. In addition, we find that at criticality, the connectivities depend on the linear finite size L as ˜Lyt-d, and the associated specific-heat-like quantities Cn and Cnn scale as ˜L2yt-dln(L /L0), where d is the lattice dimensionality, yt=1/? the thermal renormalization exponent, and L0 a nonuniversal constant. We provide an explanation of this logarithmic factor within the theoretical framework reported recently by Vasseur et al. [J. Stat. Mech. (2012) L07001, 10.1088/1742-5468/2012/07/L07001].

Hu, Hao; Blöte, Henk W. J.; Ziff, Robert M.; Deng, Youjin

2014-10-01

315

Neural networks, field theory, directed percolation, and critical branching  

NASA Astrophysics Data System (ADS)

We describe the dynamics of neural activity using field-theoretic methods for non-equilibrium statistical processes. Using a Markov assumption, we introduce the "spike model". The spike model permits a characterization of both neural fluctuations and response, presenting a tractable way to extend the mean field (Wilson-Cowan) equations used in much of theoretical and computational neuroscience. We also demonstrate the formalism's application to the Cowan models, one of which is equivalent to the forest fire model with immune trees. We argue that neural activity under mild conditions exhibits a dynamical phase transition which is in the universality class of directed percolation (DP). Owing to the spatial extent of neural interactions, there is a region in which the critical behavior is that of a branching process before crossing over into the DP region, consistent with measurements in cortical slice preparations. From the perspective of theoretical neuroscience, a principal contribution of this work is the connection of the problem of non-linear, non-Gaussian systems with the problem of dealing with infrared singularities in field theory. This work suggests a general characterization of epilepsy as a manifestation of a directed percolation phase transition.

Buice, Michael A.

316

Ultralow percolation threshold in aerogel and cryogel templated composites.  

PubMed

We demonstrate a novel concept for preparing percolating composites with ultralow filler content by utilizing nanofiller-loaded aerogel and cryogels as a conductive template. This concept is investigated for several porous systems, including resorcinol-formaldehyde (RF), silica, and polyacrylamide (PAM) gels, and both graphene and carbon nanotubes are utilized as nanofiller. In each case, a stable, aqueous nanofiller dispersion is mixed with a sol-gel precursor and polymerized to form a hydrogel, which can then be converted to an aerogel by critical point drying or cryogel by freeze-drying. Epoxy resin is infused into the pores of the gels by capillary action without disrupting the monolithic structure. We show that conductive graphene/epoxy composites are formed with a very low graphene loading; a percolation threshold as low as 0.012 vol % is obtained for graphene-RF cryogel/epoxy composite. This is the lowest reported threshold of any graphene-based nanocomposites. Similar values are achieved in other aerogel and nanofiller systems, which demonstrates the versatility of this method. PMID:23927050

Irin, Fahmida; Das, Sriya; Atore, Francis O; Green, Micah J

2013-09-10

317

Role of local and global geometry in entanglement percolation  

NASA Astrophysics Data System (ADS)

We prove that enhanced entanglement percolation via lattice transformation is possible even if the new lattice is more poorly connected in that (i) the coordination number (a local property) decreases, or (ii) the classical percolation threshold (a global property) increases. In searching for protocols to transport entanglement across a network, it seems reasonable to try transformations that increase connectivity. In fact, all examples that we are aware of violate both conditions (i) and (ii). One might therefore conjecture that all good transformations must violate them. Here we introduce a method, partial entanglement swapping, and use it to construct a counterexample that satisfies conditions (i) and (ii). The example lowers the threshold, relative to all known protocols, of the amount of initial entanglement required for deterministic long-range entanglement. This result shows that a transformation may not be rejected on the basis of satisfying conditions (i) or (ii). Both the result and the method constitute steps toward answering basic questions, such as whether there is a minimum amount of local entanglement required to achieve long-range entanglement.

Lapeyre, Gerald John

2014-01-01

318

Epoxy resin/carbon black composites below the percolation threshold.  

PubMed

A set of epoxy resin composites filled with 0.25-2.0 wt.% of commercially available ENSACO carbon black (CB) of high and low surface area (CBH and CBL respectively) has been produced. The results of broadband dielectric spectroscopy of manufactured CB/epoxy below the percolation threshold in broad temperature (200 K to 450 K) and frequency (20 Hz to 1 MHz) ranges are reported. The dielectric properties of composites below the percolation threshold are mostly determined by alpha relaxation in pure polymer matrix. The glass transition temperature for CB/epoxy decreases in comparison with neat epoxy resin due to the extra free volume at the polymer-filler interface. At room temperature, the dielectric permittivity is higher for epoxy loaded with CBH additives. In contrast, at high temperature, the electrical conductivity was found to be higher for composites with CBL embedded. The established influence of the CB surface area on the broadband dielectric characteristics can be exploited for the production of effective low-cost antistatic paints and coatings working at different temperatures. PMID:23882775

Macutkevic, J; Kuzhir, P; Paddubskaya, A; Maksimenko, S; Banys, J; Celzard, A; Fierro, V; Stefanutti, E; Cataldo, A; Micciulla, F; Bellucci, S

2013-08-01

319

Agglomerative percolation on the Bethe lattice and the triangular cactus  

NASA Astrophysics Data System (ADS)

Agglomerative percolation (AP) on the Bethe lattice and the triangular cactus is studied to establish the exact mean-field theory for AP. Using the self-consistent simulation method based on the exact self-consistent equations, the order parameter P? and the average cluster size S are measured. From the measured P? and S, the critical exponents ?k and ?k for k = 2 and 3 are evaluated. Here, ?k and ?k are the critical exponents for P? and S when the growth of clusters spontaneously breaks the Zk symmetry of the k-partite graph. The obtained values are ?2 = 1.79(3), ?2 = 0.88(1), ?3 = 1.35(5) and ?3 = 0.94(2). By comparing these exponents with those for ordinary percolation (?? = 1 and ?? = 1), we also find ?? < ?3 < ?2 and ?? > ?3 > ?2. These results quantitatively verify the conjecture that the AP model belongs to a new universality class if the Zk symmetry is broken spontaneously, and the new universality class depends on k.

Chae, Huiseung; Yook, Soon-Hyung; Kim, Yup

2013-08-01

320

Emulsified industrial oils recycling  

SciTech Connect

The industrial lubricant market has been analyzed with emphasis on current and/or developing recycling and re-refining technologies. This task has been performed for the United States and other industrialized countries, specifically France, West Germany, Italy and Japan. Attention has been focused at emulsion-type fluids regardless of the industrial application involved. It was found that emulsion-type fluids in the United States represent a much higher percentage of the total fluids used than in other industrialized countries. While recycling is an active matter explored by the industry, re-refining is rather a result of other issues than the mere fact that oil can be regenerated from a used industrial emulsion. To extend the longevity of an emulsion is a logical step to keep expenses down by using the emulsion as long as possible. There is, however, another important factor influencing this issue: regulations governing the disposal of such fluids. The ecological question, the respect for nature and the natural balances, is often seen now as everybody's task. Regulations forbid dumping used emulsions in the environment without prior treatment of the water phase and separation of the oil phase. This is a costly procedure, so recycling is attractive since it postpones the problem. It is questionable whether re-refining of these emulsions - as a business - could stand on its own if these emulsions did not have to be taken apart for disposal purposes. Once the emulsion is separated into a water and an oil phase, however, re-refining of the oil does become economical.

Gabris, T.

1982-04-01

321

Energy and Recycling  

NSDL National Science Digital Library

Energy and Garbage is one section of a US Department of Energy's educational Web site for kids. Features of this Web site include a section detailing the connection between energy and garbage, a thorough introduction to the history of garbage that includes facts and figures on how much waste we produce, information on recycling and reducing garbage at the source, and much more. The information in this Web site is presented in a friendly, narrative style. A short downloadable activity titled Energy from Garbage, created by the National Energy Education Development Project, is also available (grades 4-6).

322

Recycled rubber roads  

SciTech Connect

The paper describes several innovative approaches for recycling old tires in the construction of roads. In one, 18 inches of shredded tire chips (2 X 2 inches) were used on top of 6-8 inches of small stone to construct a road across a sanitary landfill. No compacting or linders were needed. In another application, sidewall mats linked together with steel strapping were used as a sub-base for a road across a swampy area. A third application uses 1/2 inch bits of groundup rubber tires as a replacement for aggregate in an asphalt road base.

Not Available

1989-02-01

323

Novel Regenerated Solvent Extraction Processes for the Recovery of Carboxylic Acids or Ammonia from Aqueous Solutions Part II. Recovery of Ammonia from Sour Waters  

SciTech Connect

Two novel regenerated solvent extraction processes are examined. The first process has the potential to reduce the energy costs inherent in the recovery of low-volatility carboxylic acids from dilute aqueous solutions. The second process has the potential for reducing the energy costs required for separate recovery of ammonia and acid gases (e.g. CO{sub 2} and H{sub 2}S) from industrial sour waters. The recovery of carboxylic acids from dilute aqueous solution can be achieved by extraction with tertiary amines. An approach for regeneration and product recovery from such extracts is to back-extract the carboxylic acid with a water-soluble, volatile tertiary amine, such as trimethylamine. The resulting trimethylammonium carboxylate solution can be concentrated and thermally decomposed, yielding the product acid and the volatile amine for recycle. Experimental work was performed with lactic acid, SUCCiOlC acid, and fumaric acid. Equilibrium data show near-stoichiometric recovery of the carboxylic acids from an organic solution of Alamine 336 into aqueous solutions of trimethylamine. For fumaric and succinic acids, partial evaporation of the aqueous back extract decomposes the carboxylate and yields the acid product in crystalline form. The decomposition of aqueous solutions of trimethylammonium lactates was not carried out to completion, due to the high water solubility of lactic acid and the tendency of the acid to self-associate. The separate recovery of ammonia and acid gases from sour waters can be achieved by combining steam-stripping of the acid gases with simultaneous removal of ammonia by extraction with a liquid cation exchanger. The use of di-2,4,4-trimethylpentyl phosphinic acid as the liquid cation exchanger is explored in this work. Batch extraction experiments were carried out to measure the equilibrium distribution ratio of ammonia between an aqueous buffer solution and an organic solution of the phosphinic acid (0.2N) in Norpar 12. The concentration-based distribution ratios increase from 0.11 to 0.46 as the aqueous phase pH increases from 7.18 to 8.15. Regeneration of the organic extractant solution was carried out by stripping at elevated temperatures to remove the ammonia, with 99% recovery of the ammonia being obtained at 125 C.

Poole, L.J.; King, C.J.

1990-03-01

324

Closed Loop Recycling of PreservativeClosed Loop Recycling of Preservative Treated WoodTreated Wood  

E-print Network

Closed Loop Recycling of PreservativeClosed Loop Recycling of Preservative Treated WoodTreated WoodDisposal problem Recycling potentialRecycling potential ValueValue--added productsadded products Closed loop recyclingClosed loop recycling #12;Major Current Disposal OptionsMajor Current Disposal Options Incineration

325

Mechanism of ammonia detection by chemically functionalized single-walled carbon nanotubes: in situ electrical and optical study of gas analyte detection.  

PubMed

We provide definitive evidence for the mechanism of electronic detection of ammonia by monitoring in situ changes in the electrical resistance and optical spectra of films of poly(m-aminobenzenesulfonic acid)-functionalized SWNTs (SWNT-PABS). The increase of resistance during exposure to ammonia is associated with deprotonation of the PABS side chain that in turn induces electron transfer between the oligomer and the valence band of the semiconducting SWNTs. Near IR spectroscopy is used to demonstrate that the charge transfer is a weakly driven process, and this accounts for the high reversibility of the sensor. We show that the sensitivity of the chemiresistors increases as the film thickness is reduced to the percolation threshold and that the SWNT-PABS film thickness provides a simple means to enhance the electronic response. PMID:17696430

Bekyarova, Elena; Kalinina, Irina; Itkis, Mikhail E; Beer, Leanne; Cabrera, Nelson; Haddon, Robert C

2007-09-01

326

Percolation approach to the problem of hydraulic conductivity in porous media  

Microsoft Academic Search

While percolation theory has been studied extensively in the field of physics, and the literature devoted to the subject is vast, little use of its results has been made to date in the field of hydrology. In the present study, we carry out Monte Carlo computer simulations on a percolating model representative of a porous medium. The model considers intersecting

B. Berkowitz; I. Balberg

1992-01-01

327

Hierarchical aggregation in percolation model Ilya Zaliapin a,*, Henry Wong a  

E-print Network

a Institute of Geophysics and Planetary Physics, University of California Los Angeles, Slichter Hall 3845, CA-percolation is a simple and tractable model which exhibits such important general features of complex systems originated from the percolation model). The results can be used for development and improvement of earthquake

Gabrielov, Andrei

328

Traveling time and traveling length in critical percolation clusters Youngki Lee,1  

E-print Network

and ground-water pollution 1­5 . Here we study an incompressible flow on two- dimensional bond percolation for tracer dispersion in two-dimensional bond percolation, modeling flow by tracer particles driven by a pressure difference between two points separated by Euclidean distance r. We find that the minimal

Stanley, H. Eugene

329

THE SPEED OF A BIASED RANDOM WALK ON A PERCOLATION CLUSTER AT HIGH DENSITY  

E-print Network

THE SPEED OF A BIASED RANDOM WALK ON A PERCOLATION CLUSTER AT HIGH DENSITY ALEXANDER FRIBERGH Abstract. We study the speed of a biased random walk on a percolation cluster on Zd in function in random media. In the last few years a lot of work has been done to understand these models on Zd , one

330

Percolation model of immiscible displacement in the presence of buoyancy forces  

Microsoft Academic Search

We consider the quasistatic displacement of a nonwetting fluid by a wetting one in a porous medium in the presence of buoyancy forces. A simple percolation model of this process is presented and analyzed both theoretically and by Monte Carlo simulation. It is shown that the fact that percolation is a critical phenomenon, with diverging correlation length at the critical

David Wilkinson

1984-01-01

331

Geometry and dynamics of invasion percolation with correlated buoyancy Jean Schmittbuhl and Alex Hansen*  

E-print Network

Geometry and dynamics of invasion percolation with correlated buoyancy Jean Schmittbuhl and Alex in a rough self­affine landscape. As a function of the buoyancy, the geometry of the invaded clusters changes to the buoyancy. PACS number#s#: 47.55.Mh, 47.55.Kf, 64.60.Ak, 91.45.Vz I. INTRODUCTION Invasion percolation #1

Schmittbuhl, Jean

332

Surface Rheology of Two-Dimensional Percolating Networks: Langmuir Films of Polymer Pancakes  

NASA Astrophysics Data System (ADS)

We report surface rheological measurements on Langmuir films of submicron-sized polymer coils (pancakes). The dynamics of the sol phase is found to be governed by free volume as in the simplest percolation problem. The observed rheology of the percolated phase (gel-like) is compatible with predictions for compressed arrangements of highly deformed soft particles interacting through their contact interfaces.

Monroy, Francisco; Ortega, Francisco; Rubio, Ramón G.; Ritacco, Hernán; Langevin, Dominique

2005-07-01

333

Transfer matrix calculation of conductivity in three-dimensional random resistor networks at percolation threshold  

E-print Network

L-701 Transfer matrix calculation of conductivity in three-dimensional random resistor networks the conductivity of a random network of resistors and insulators. At the percolation threshold in a simple cubic. For the evaluation of the conductivity in random resistor networks [2] at the percolation threshold this has been

Paris-Sud XI, Université de

334

Submitted to the Annals of Probability INHOMOGENEOUS BOND PERCOLATION ON SQUARE,  

E-print Network

-crossing (RSW) inequalities for such models with parameter-values at which the transformation is valid, the RSW box-crossing lemmas of [26, 27] have a key role in the study of the conformality of critical 82B43. Keywords and phrases: Bond percolation, inhomogeneous percolation, RSW lemma, box

Grimmett, Geoffrey

335

Testing of an ammonia ion selective electrode for ammonia nitrogen measurement in the methanogenic sludge  

Microsoft Academic Search

The ammonia ion selective electrode method was the most practical and the most convenient one for measuring the ammonia nitrogen in methanogenic sludge. This is because of its simplicity, rapidity, high precision and accuracy, freedom from interference, small sample size, and possibility for continuous monitoring.

Anh LeDuy; Rejean Samson

1982-01-01

336

RECYCLING AND GENERAL WASTE MANAGEMENT OPERATIONAL PROCEDURE  

E-print Network

RECYCLING AND GENERAL WASTE MANAGEMENT OPERATIONAL PROCEDURE Swansea University Estates Services.6.1/1 Recycling & General Waste Management Department: Estates & Facilities Management Site: Swansea University recycling and waste management facilities in Swansea university To ensure that Waste Management Objectives

Harman, Neal.A.

337

The Economic Benefits of Recycling in Virginia  

E-print Network

The Economic Benefits of Recycling in Virginia Alexander P. Miller Hang T. Nguyen Samantha D, and the recycling contacts from the participating Solid Waste Planning Units discussed in this study. #12;3 Table Determinants of Recycling_______________________________ 12 State Reports

Lewis, Robert Michael

338

RECYCLING: SUPPLY, ECONOMICS, ENVIRONMENT, AND TECHNOLOGY  

E-print Network

RECYCLING: SUPPLY, ECONOMICS, ENVIRONMENT, AND TECHNOLOGY Panel Discussion Roundtable Moderator: S, although higher market values for recyclable will certainly stimulate increased interest in collection in recycling and deinking technologies and process design among North American, European, and Pacific Rim

Abubakr, Said

339

Flooding and Recycling Authorizations Konstantin (Kosta) Beznosov  

E-print Network

Flooding and Recycling Authorizations Konstantin (Kosta) Beznosov Laboratory for Education delivery channels with speculatively pre- computed authorizations and actively recycling them on a just Security Keywords authorization recycling, authorization flooding, access con- trol, authorization, publish

340

16 CFR 260.12 - Recyclable claims.  

Code of Federal Regulations, 2013 CFR

...otherwise recovered from the waste stream through an established recycling program for reuse or use...about the availability of recycling programs and collection sites to consumers. (1) When recycling facilities are available...

2013-01-01

341

16 CFR 260.12 - Recyclable claims.  

...otherwise recovered from the waste stream through an established recycling program for reuse or use...about the availability of recycling programs and collection sites to consumers. (1) When recycling facilities are available...

2014-01-01

342

Percolation and lasing in real 3D crystals with inhomogeneous distributed random pores  

NASA Astrophysics Data System (ADS)

We systematically study the percolation phase transition in real 3D crystals where not only the state of pores but also their radius r and displacement s are random valued numbers. The mean values R= and S= emerge as additional spatial scales in such an extended network. This leads to variations of the threshold (critical) percolation probability pC and the percolation order parameter P that become to be the intricate functions of R and S. Our numerical simulations have shown that in such extended system the incipient spanning cluster can arise even for situations where for simple periodical system the percolation does not exist. We analyzed the validity of the nearest neighbor's approximation and found that such approximation is not valid for materials with large dispersivity of pores. The lasing of nanoemitters incorporated in such percolating spanning cluster is studied too. This effect can open interesting perspectives in modern nano- and micro-information technologies.

Burlak, Gennadiy; Calderón-Segura, Yessica

2014-11-01

343

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Oakwood Apartments Metals, Glass and Plastics can be recycled in the outside

Sibille, Etienne

344

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Brackenridge Hall Metals, Glass and Plastics can be recycled in the trashroom

Sibille, Etienne

345

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Lothrop Hall Metals, Glass and Plastics can be recycled in the trashrooms. Paper

Sibille, Etienne

346

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Darragh Street Apartments Metals, Glass and Plastics can be recycled

Sibille, Etienne

347

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Forbes-Craig Metals, Glass and Plastics can be recycled in the outside toters

Sibille, Etienne

348

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered McCormick Hall Metals, Glass and Plastics can be recycled in the trashroom

Sibille, Etienne

349

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing s Plastics Numbered Litchfield Towers Metals, Glass and Plastics can be recycled in the trashroom

Sibille, Etienne

350

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Pennsylvania Hall Metals, Glass and Plastics can be recycled in the trashroom

Sibille, Etienne

351

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Sutherland Hall Metals, Glass and Plastics can be recycled in the trashroom

Sibille, Etienne

352

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing and Food Plastics Numbered Forbes Hall Metals, Glass and Plastics can be recycled in the trashroom

Sibille, Etienne

353

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Ruskin Hall Metals, Glass and Plastics can be recycled in the trashrooms. Paper

Sibille, Etienne

354

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Fraternity Houses Metals, Glass and Plastics can be recycled in the outside

Sibille, Etienne

355

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Centre Plaza Metals, Glass and Plastics can be recycled by the elevators. Paper

Sibille, Etienne

356

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Panther Hall Metals, Glass and Plastics can be recycled in the trashroom. Paper

Sibille, Etienne

357

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Bruce Hall Metals, Glass and Plastics can be recycled in the laundry room. Paper

Sibille, Etienne

358

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Bouquet Gardens Metals, Glass and Plastics can be recycled in the outside toters

Sibille, Etienne

359

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Amos Hall Metals, Glass and Plastics can be recycled in the kitchen. Paper

Sibille, Etienne

360

PITT RECYCLES! *Please empty cans!  

E-print Network

for one of these numbers! Clear glass Green glass Brown glass Blue glass *Please empty containers! Other Plastics Paper Glass Ink cartridges Batteries Cell Phones Can be recycled at drop-off boxes around campus of Housing Plastics Numbered Holland Hall Metals, Glass and Plastics can be recycled in the trashroom. Paper

Sibille, Etienne

361

Recycled Wind: A Sound Installation  

Microsoft Academic Search

Recycled Wind is a sound installation in which a visitor's breath is emulated mechanically. Sensors detect the breath and trigger small fans, which blow sound-making objects such as wind chimes and leaves. Like the wind itself, the chimes and leaves are emulated, constructed of recycled materials such as jar lids and grocery bags.

Adam Scott Neal

362

Tritium recycling (processing) facility design  

Microsoft Academic Search

The maintenance of a nuclear weapons capability requires the periodic replacement of tritium contained in each of the weapons in the nuclear weapons stockpile because the radioactive decay of tritium reduces its quantity by about 5.5 percent per year. The Tritium Recycling Plant (TRP) performs the activities necessary to recover, purify, and recycle tritium returned from the field. Tritium is

J. Metzler; T. Le

1995-01-01

363

Bacterial cell-wall recycling  

PubMed Central

Many Gram-negative and Gram-positive bacteria recycle a significant proportion of the peptidoglycan components of their cell walls during their growth and septation. In many—and quite possibly all—bacteria, the peptidoglycan fragments are recovered and recycled. While cell-wall recycling is beneficial for the recovery of resources, it also serves as a mechanism to detect cell-wall–targeting antibiotics and to regulate resistance mechanisms. In several Gram-negative pathogens, anhydro-MurNAc-peptide cell-wall fragments regulate AmpC ?-lactamase induction. In some Gram-positive organisms, short peptides derived from the cell wall regulate the induction of both ?-lactamase and ?-lactam-resistant penicillin-binding proteins. The involvement of peptidoglycan recycling with resistance regulation suggests that inhibitors of the enzymes involved in the recycling might synergize with cell-wall-targeted antibiotics. Indeed, such inhibitors improve the potency of ?-lactams in vitro against inducible AmpC ?-lactamase-producing bacteria. We describe the key steps of cell-wall remodeling and recycling, the regulation of resistance mechanisms by cell-wall recycling, and recent advances toward the discovery of cell-wall recycling inhibitors. PMID:23163477

Johnson, Jarrod W.; Fisher, Jed F.; Mobashery, Shahriar

2012-01-01

364

Review Article: Recycling of Polystyrene  

Microsoft Academic Search

Recycling of polystyrene can be done by mechanical, chemical, and thermal methods. High impact polystyrene is a promising material for mechanical recycling since its properties are not extremely affected even after multiple processing of upto nine cycles. Production of liquid products and gaseous products are highly dependent on the reaction condition. The catalysts used are highly selective for the production

T. Maharana; Y. S. Negi; B. Mohanty

2007-01-01

365

TOMATO CLEANING AND WATER RECYCLE  

EPA Science Inventory

A full-scale dump tank water recycle system was developed and demonstrated. A false bottom-ejector transport system removed soil from the water. Clarified water was either recycled back to the dump tank or discharged to the sewer. A vacuum belt was developed for dewatering the mu...

366

Roughness of Interfacial Crack Fronts: Stress-Weighted Percolation in the Damage Zone Jean Schmittbuhl* and Alex Hansen  

E-print Network

Roughness of Interfacial Crack Fronts: Stress-Weighted Percolation in the Damage Zone Jean that the roughness exponent is related to the correlation length exponent of a stress-weighted percolation problem through =1 . A numerical study of the stress-weighted percolation problem yields 1:54 giving 0

Schmittbuhl, Jean

367

Percolation transitions in bilayer graphene encapsulated by hexagonal boron nitride  

NASA Astrophysics Data System (ADS)

We studied the plateau-plateau transitions that characterize the electrical transport in the quantum Hall regime in a high mobility bilayer graphene flake encapsulated by hexagonal boron nitride at magnetic fields up to 9 T and temperatures above 300 mK. We measured independently the exponent ? of the temperature-induced transition broadening, the critical exponent ? of the localization length, and the exponent p ruling the temperature scaling of the coherence length, finding consistency with the relation ? =p /2 ? . The observed value of ? =0.30 (0.28 ,0.32 ) deviates from that of the quantum Hall critical point. The obtained ? =1.25 (0.96 ,1.54 ) questions the validity of a pure Anderson transition, and reveals percolation as the underlying driving mechanism.

Cobaleda, C.; Pezzini, S.; Rodriguez, A.; Diez, E.; Bellani, V.

2014-10-01

368

On the Percolation BCFT and the Crossing Probability of Watts  

E-print Network

The logarithmic conformal field theory describing critical percolation is further explored using Watts' determination of the probability that there exists a cluster connecting both horizontal and vertical edges. The boundary condition changing operator which governs Watts' computation is identified with a primary field which does not fit naturally within the extended Kac table. Instead a "shifted" extended Kac table is shown to be relevant. Augmenting the previously known logarithmic theory based on Cardy's crossing probability by this field, a larger theory is obtained, in which new classes of indecomposable rank-2 modules are present. No rank-3 Jordan cells are yet observed. A highly non-trivial check of the identification of Watts' field is that no Gurarie-Ludwig-type inconsistencies are observed in this augmentation. The article concludes with an extended discussion of various topics related to extending these results including projectivity, boundary sectors and inconsistency loopholes.

David Ridout

2008-08-26

369

Minimal spanning trees at the percolation threshold: a numerical calculation  

NASA Astrophysics Data System (ADS)

Through computer simulations on a hypercubic lattice, we grow minimal spanning trees (MSTs) in up to five dimensions and examine their fractal dimensions. Understanding MSTs is imporant for studying systems with quenched disorder such as spin glasses. We implement a combination of Prim's and Kruskal's algorithms for finding MSTs in order to reduce memory usage and allow for simulation of larger systems than would otherwise be possible. These fractal objects are analyzed in an attempt to numerically verify predictions of the perturbation expansion developed by T. S. Jackson and N. Read for the pathlength fractal dimension ds of MSTs on percolation clusters at criticality [T. S. Jackson and N. Read, Phys. Rev. E 81, 021131 (2010)]. Examining these trees also sparked the development of an analysis technique for dealing with correlated data that could be easily generalized to other systems and should be a robust method for analyzing a wide array of randomly generated fractal structures.

Sweeney, Sean; Middleton, A. Alan

2013-03-01

370

Bootstrap percolation and kinetically constrained models on hyperbolic lattices  

E-print Network

We study bootstrap percolation (BP) on hyperbolic lattices obtained by regular tilings of the hyperbolic plane. Our work is motivated by the connection between the BP transition and the dynamical transition of kinetically constrained models, which are in turn relevant for the study of glass and jamming transitions. We show that for generic tilings there exists a BP transition at a nontrivial critical density, $0<\\rho_c<1$. Thus, despite the presence of loops on all length scales in hyperbolic lattices, the behavior is very different from that on Euclidean lattices where the critical density is either zero or one. Furthermore, we show that the transition has a mixed character since it is discontinuous but characterized by a diverging correlation length, similarly to what happens on Bethe lattices and random graphs of constant connectivity.

François Sausset; Cristina Toninelli; Giulio Biroli; Gilles Tarjus

2009-07-06

371

Anisotropy in Fracking: A Percolation Model for Observed Microseismicity  

E-print Network

Hydraulic fracturing (fracking) using high pressures and a low viscosity fluid allow the extraction of large quantiles of oil and gas from very low permeability shale formations. The initial production of oil and gas at depth leads to high pressures and an extensive distribution of natural fractures which reduce the pressures. With time these fractures heal, sealing the remaining oil and gas in place. High volume fracking opens the healed fractures allowing the oil and gas to flow the horizontal productions wells. We model the injection process using invasion percolation. We utilize a 2D square lattice of bonds to model the sealed natural fractures. The bonds are assigned random strengths and the fluid, injected at a point, opens the weakest bond adjacent to the growing cluster of opened bonds. Our model exhibits burst dynamics in which the clusters extends rapidly into regions with weak bonds. We associate these bursts with the microseismic activity generated by fracking injections. A principal object of thi...

Norris, J Quinn; Rundle, John B

2014-01-01

372

Percolation approach to glassy dynamics with continuously broken ergodicity  

NASA Astrophysics Data System (ADS)

We show that the relaxation dynamics near a glass transition with continuous ergodicity breaking can be endowed with a geometric interpretation based on percolation theory. At the mean-field level this approach is consistent with the mode-coupling theory (MCT) of type-A liquid-glass transitions and allows one to disentangle the universal and nonuniversal contributions to MCT relaxation exponents. Scaling predictions for the time correlation function are successfully tested in the F12 schematic model and facilitated spin systems on a Bethe lattice. Our approach immediately suggests the extension of MCT scaling laws to finite spatial dimensions and yields predictions for dynamic relaxation exponents below an upper critical dimension of 6.

Arenzon, Jeferson J.; Coniglio, Antonio; Fierro, Annalisa; Sellitto, Mauro

2014-08-01

373

Link overlap, viability, and mutual percolation in multiplex networks  

E-print Network

Many real-world complex systems are best modeled by multiplex networks. The multiplexity has proved to have broad impact on the system's structure and function. Most theoretical studies on multiplex networks to date, however, have largely ignored the effect of link overlap across layers despite strong empirical evidences for its significance. In this article, we investigate the effect of link overlap in the viability of multiplex networks, both analytically and numerically. Distinctive role of overlapping links in viability and mutual connectivity is emphasized and exploited for setting up proper analytic framework. A rich phase diagram for viability is obtained and greatly diversified patterns of hysteretic behavior in viability are observed in the presence of link overlap. Mutual percolation with link overlap is revisited as a limit of multiplex viability problem, and controversy between existing results is clarified. The distinctive role of overlapping links is further demonstrated by the different respons...

Min, Byungjoon; Lee, Kyu-Min; Goh, K -I

2014-01-01

374

Active Percolation Analysis of Pyramidal Neurons of Somatosensory Cortex:  

NASA Astrophysics Data System (ADS)

This article describes the investigation of morphological variations among two sets of neuronal cells, namely a control group of wild type mouse cells and a group of cells of a transgenic line. Special attention is given to singular points in the neuronal structure, namely the branching points and extremities of the dendritic processes. The characterization of the spatial distribution of such points is obtained by using a recently reported morphological technique based on forced percolation and window-size compensation, which is particularly suited to the analysis of scattered points, presenting several coexisting densities. Different dispersions were identified in our statistical analysis, suggesting that the transgenic line of neurons is characterized by a more pronounced morphological variation. A classification scheme based on a canonical discriminant function was also considered in order to identify the morphological differences.

Costa, Luciano Da Fontoura; Barbosa, Marconi Soares; Schierwagen, Andreas; Alpár, Alán; Gärtner, Ulrich; Arendt, Thomas

375

Algorithm to determine the percolation largest component in interconnected networks  

NASA Astrophysics Data System (ADS)

Interconnected networks have been shown to be much more vulnerable to random and targeted failures than isolated ones, raising several interesting questions regarding the identification and mitigation of their risk. The paradigm to address these questions is the percolation model, where the resilience of the system is quantified by the dependence of the size of the largest cluster on the number of failures. Numerically, the major challenge is the identification of this cluster and the calculation of its size. Here, we propose an efficient algorithm to tackle this problem. We show that the algorithm scales as O(NlogN), where N is the number of nodes in the network, a significant improvement compared to O(N2) for a greedy algorithm, which permits studying much larger networks. Our new strategy can be applied to any network topology and distribution of interdependencies, as well as any sequence of failures.

Schneider, Christian M.; Araújo, Nuno A. M.; Herrmann, Hans J.

2013-04-01

376

Conductivity percolation in carbon-carbon supercapacitor electrodes  

NASA Astrophysics Data System (ADS)

Composite electrodes which comprise a non-conductive activated carbon of large surface area (1420 m 2 g -1) and a conductive carbon black (CB) of small surface area (220 m 2 g -1) have been prepared and studied for their capacitive properties in aqueous KOH and Na 2SO 4 electrolytes. For either electrolyte, maximum capacitance exists at the composition believed to correspond to the percolation threshold for CB, the conductive phase. At a CB content less than the threshold, the capacitance is limited mainly by the electronic resistance on the electrode side. The interfacial surface area becomes the limiting factor as the threshold is exceeded. A maximum capacitance of 108 F g -1 at a voltage sweep rate of 20 mV s -1 is obtained in 1 M KOH aqueous electrolyte with a CB content of 25 wt.% (or ˜14 vol.%).

Wu, N. L.; Wang, S. Y.

377

A Cube Dismantling Problem Related to Bootstrap Percolation  

NASA Astrophysics Data System (ADS)

An n× n×⋯× n hypercube is made from n d unit hypercubes. Two unit hypercubes are neighbours if they share a ( d-1)-dimensional face. In each step of a dismantling process, we remove a unit hypercube that has precisely d neighbours. A move is balanced if the neighbours are in d orthogonal directions. In the extremal case, there are n d-1 independent unit hypercubes left at the end of the dismantling. We call this set of hypercubes a solution. If a solution is projected in d orthogonal directions and we get the entire [ n] d-1 hypercube in each direction, then the solution is perfect. We show that it is possible to use a greedy algorithm to test whether a set of hypercubes forms a solution. Perfect solutions turn out to be precisely those which can be reached using only balanced moves. Every perfect solution corresponds naturally to a Latin hypercube. However, we show that almost all Latin hypercubes do not correspond to solutions. In three dimensions, we find at least n perfect solutions for every n, and we use our greedy algorithm to count the perfect solutions for n?6. We also construct an infinite family of imperfect solutions and show that the total size of its three orthogonal projections is asymptotic to the minimum possible value. Our results solve several conjectures posed in a proceedings paper by Barát, Korondi and Varga. If our dismantling process is reversed we get a build-up process very closely related to well-studied models of bootstrap percolation. We show that in an important special case our build-up reaches the same maximal position as bootstrap percolation.

Barát, János; Wanless, Ian M.

2012-11-01

378

Exploring Waste and Recycling  

NSDL National Science Digital Library

This resource, created by Eleanor Camann of Red Rocks Community College, will introduce students to the concept of sustainability in terms of waste products and recycling practices. The overall premise of the project is to "get students to think critically about which earth materials are used to make things, and where all the waste from both mining and consumption ends up." The activity employs skills in basic mathematics, reasoning and writing. It also crosses disciplines by implementing skills in environmental geology and science. The learning activity only takes about two hours of in-class time and an additional three outside of the classroom. It uses simple materials such as a calculator, periodic table, household scale and digital camera. Lessons plans such as these are supported by a grant under the National Science Foundation's Advanced Technological Education (ATE) program.

Camann, Eleanor

2010-11-09

379

Environmentally acceptable recycling in Europe  

SciTech Connect

The modern concept of ecologically sound recycling is to ensure, as far as possible, effective use or reuse of all materials arising during the production of a component, and also the component itself at the end of its useful life. The recycling circle is well established for widely used metals such as iron and steel, aluminium and zinc. However, for magnesium, although recycled secondary scrap was a major input into magnesium casting production in the 1950`s recycling of this type of material back to components is currently almost nonexistent. The current rapid growth in use of magnesium die castings by the automotive industry will eventually result in a significant growth in availability of secondary magnesium scrap, which will present new challenges and opportunities to the skillful recyclers. However this has not yet happened, and the major preoccupation of most recyclers is to satisfy the demands of the growing die-casting industry, balancing the triple requirements of: (1) recycling or disposing of all products arising from the die-casting operation at a price, or cost, perceived as fair by the die caster; (2) satisfying our public demands to safeguard the environment in terms of emissions, effluents and disposal to land fill; and (3) establishing and maintaining a viable business activity while satisfying (1) and (2). It is to this area that the remainder of this paper is dedicated.

King, J.F. [Magnesium Elektron, Manchester (United Kingdom)

1995-12-31

380

Radiation damage effects in polarized deuterated ammonia  

SciTech Connect

Solid polarized targets utilizing deuterated ammonia, {sup 15}ND{sub 3}, offer an attractive combination of high polarization, high dilution factor and high resistance to polarization losses from radiation damage. Jefferson Laboratory Experiment E93-026 used {sup 15}ND{sub 3} as a target material in a five-month form factor measurement, allowing a detailed study of it's performance. The dependence of the deuteron polarization on received dose by the ammonia and the effectiveness of annealing the material to recover performance lost to radiation damage will be discussed.

P.M. McKee

2003-07-01

381

Biochemistry of Ammonia Monoxygenase from Nitrosomonas  

SciTech Connect

Major results. 1. CytochromecM552, a protein in the electron transfer chain to ammonia monooxygenase. Purification, modeling of protein structure based on primary structure, characterization of 4 hemes by magnetic spectroscopy, potentiometry, ligand binding and turnover. Kim, H. J., ,Zatsman, et al. 2008). 2. Characterization of proteins which thought to be involved in the AMO reaction or to protect AMO from toxic nitrogenous intermediates such as NO. Nitrosocyanin is a protein present only in bacteria which catalyze the ammonia monoxygenase reaction (1). Cytochrome c P460 beta and cytochrome c’ beta.

Alan Hooper

2009-07-15

382

Plastics recycling: challenges and opportunities.  

PubMed

Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. As a consequence, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Around 4 per cent of world oil and gas production, a non-renewable resource, is used as feedstock for plastics and a further 3-4% is expended to provide energy for their manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These two observations alone indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Here, we briefly set recycling into context against other waste-reduction strategies, namely reduction in material use through downgauging or product reuse, the use of alternative biodegradable materials and energy recovery as fuel. While plastics have been recycled since the 1970s, the quantities that are recycled vary geographically, according to plastic type and application. Recycling of packaging materials has seen rapid expansion over the last decades in a number of countries. Advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics are creating new opportunities for recycling, and with the combined actions of the public, industry and governments it may be possible to divert the majority of plastic waste from landfills to recycling over the next decades. PMID:19528059

Hopewell, Jefferson; Dvorak, Robert; Kosior, Edward

2009-07-27

383

Lead recycling via rotary furnaces  

SciTech Connect

The lead-acid battery recycling industry was seriously affected during the 1980s by increasing environmental protection costs and poor lead prices. The process is now being repeated in the 1990s causing further difficulties for recyclers. In Europe, many lead-acid battery recycling plants use rotary furnaces. The Darley Dale smelter, redeveloped between 1984--87, uses only rotary furnaces. A review of options for this plant has been completed and concluded in favor of further investment to exploit more fully the benefits of rotary furnace technology.

Suttie, A.B. [H.J. Enthoven and Sons, Matlock (United Kingdom)

1995-12-31

384

Recycling and Life Cycle Issues  

SciTech Connect

This chapter addresses recycling and life cycle considerations related to the growing use of lightweight materials in vehicles. The chapter first addresses the benefit of a life cycle perspective in materials choice, and the role that recycling plays in reducing energy inputs and environmental impacts in a vehicle s life cycle. Some limitations of life cycle analysis and results of several vehicle- and fleet-level assessments are drawn from published studies. With emphasis on lightweight materials such as aluminum, magnesium, and polymer composites, the status of the existing recycling infrastructure and technological challenges being faced by the industry also are discussed.

Das, Sujit [ORNL

2010-01-01

385

Design and performance of an ammonia measurement system  

E-print Network

Ammonia emissions from animal feeding operations (AFOs) have recently come under increased scrutiny. The US Environmental Protection Agency (EPA) has come under increased pressure from special interest groups to regulate ammonia. Regulation...

Boriack, Cale Nolan

2007-04-25

386

Ammonia volatilisation in waste stabilisation ponds: a cascade of misinterpretations?  

PubMed

Ammonia volatilisation has generally been reported as, or assumed to be, the main nitrogen removal mechanism in waste stabilisation ponds (WSP). Nitrogen removal via ammonia volatilisation is based on two observations: (a) in-pond pH values can reach high values (>9, even >10), so increasing the proportion of the total ammonia present as the un-ionized form or free ammonia (NH(3)); and (b) in-pond temperatures can also be high, so improving the mass transfer rate of free ammonia to the atmosphere. Consequently, one of the most widely accepted models for ammonia removal in WSP is that reported by Pano & Middlebrooks in 1982, which was developed to reflect the occurrence of these two observations. This work reports how simple mathematical models for ammonia volatilisation in WSP, in spite of the possibility of their giving good predictions, may not accurately describe the main pathways and mechanisms involved in ammonia removal in WSP. PMID:20150690

Camargo Valero, M A; Mara, D D

2010-01-01

387

A precise determination of the void percolation threshold for two distributions of overlapping spheres  

SciTech Connect

The void percolation threshold is calculated for a distribution of overlapping spheres with equal radii, and for a binary sized distribution of overlapping spheres, where half of the spheres have radii twice as large as the other half. Using systems much larger than previous work, the authors determine a much more precise value for the percolation thresholds and correlation length exponent. The values for the percolation thresholds are shown to be significantly different, in contrast with previous, less precise works that speculated that the threshold might be universal with respect to sphere size distribution.

RINTOUL,MARK DANIEL

2000-01-25

388

Ammonia Production, Excretion, Toxicity, and Defense in Fish: A Review  

PubMed Central

Many fishes are ammonotelic but some species can detoxify ammonia to glutamine or urea. Certain fish species can accumulate high levels of ammonia in the brain or defense against ammonia toxicity by enhancing the effectiveness of ammonia excretion through active NH4+transport, manipulation of ambient pH, or reduction in ammonia permeability through the branchial and cutaneous epithelia. Recent reports on ammonia toxicity in mammalian brain reveal the importance of permeation of ammonia through the blood–brain barrier and passages of ammonia and water through transporters in the plasmalemma of brain cells. Additionally, brain ammonia toxicity could be related to the passage of glutamine through the mitochondrial membranes into the mitochondrial matrix. On the other hand, recent reports on ammonia excretion in fish confirm the involvement of Rhesus glycoproteins in the branchial and cutaneous epithelia. Therefore, this review focuses on both the earlier literature and the up-to-date information on the problems and mechanisms concerning the permeation of ammonia, as NH3, NH4+ or proton-neutral nitrogenous compounds, across mitochondrial membranes, the blood–brain barrier, the plasmalemma of neurons, and the branchial and cutaneous epithelia of fish. It also addresses how certain fishes with high ammonia tolerance defend against ammonia toxicity through the regulation of the permeation of ammonia and related nitrogenous compounds through various types of membranes. It is hoped that this review would revive the interests in investigations on the passage of ammonia through the mitochondrial membranes and the blood–brain barrier of ammonotelic fishes and fishes with high brain ammonia tolerance, respectively. PMID:21423375

Ip, Yuen K.; Chew, Shit F.

2010-01-01

389

The Three Rs: Reduce, Reuse, Recycle.  

ERIC Educational Resources Information Center

A student hand-out for a recycling unit defines the terms reduce, recycle, and reuse as they relate to solid waste management. Presents the characteristics of recyclable items such as yard wastes, metals, glass, and paper. Lists organizations through which more information about recycling can be obtained. (MCO)

Science Activities, 1991

1991-01-01

390

Waste Toolkit A-Z Battery recycling  

E-print Network

Waste Toolkit A-Z Battery recycling How can I recycle batteries? The University Safety Office make their own arrangements through a registered hazardous waste carrier. Batteries must not be put in normal waste bins or recycling boxes. To recycle batteries, select either option 1 or 2 below: Option 1

Melham, Tom

391

RECYCLING PROGRAM TYPE LOCATION ALLOWED NOT ALLOWED  

E-print Network

RECYCLING PROGRAM TYPE LOCATION ALLOWED NOT ALLOWED Batteries, toner, ink cartridges & cell phones and recycling is an important part of that effort. Below is a guide to on-campus recycling at RSMAS: Visit http://www.rsmas.miami.edu/msgso/ for map of recycling bin locations. NOTE: This is not an exhaustive list. If unauthorized items are found

Miami, University of

392

Ink and Toner Recycling Rewards Program Overview  

E-print Network

Ink and Toner Recycling Rewards Program Overview www.MyBusinessRecycles.com April 2013 #12;Program Overview · All BSD contract customers can participate in the MyBusinessRecycles program · Customers located in AK, HI or PR are not currently eligible. ­ Education sector customers should join the Recycling Rules

Meyers, Steven D.

393

The Environment Team to Waste & Recycling  

E-print Network

The Environment Team A-Z Guide to Waste & Recycling www.le.ac.uk/environment #12;Welcome ...to the University of Leicester's `A-Z Guide to Waste and Recycling'. Over the last 3 years, the Environment Team has introduced an award- winning recycling scheme across the campus that allows us to recycle paper, plastics

St Andrews, University of

394

Calibrationless Determination of Creatinine and Ammonia by Coulometric Flow Titration  

Microsoft Academic Search

A precise and sensitive working microflow titration procedure was developed to determine creatinine and ammonia in urine samples. This procedure is based on enzymatic conversion of creatinine, gas diffusional membrane separation of the released ammonia into an acid acceptor stream, and coulometric titration of ammonia with hypobromite. The hypobromite is formed after the electrogeneration of bromine in an electrolyte containing

Z. K. He; B. Fuhrmann; U. Spohn

2000-01-01

395

MICROBIAL AMMONIA OXIDATION IN DEEP-SEA HYDROTHERMAL PLUMES  

E-print Network

MICROBIAL AMMONIA OXIDATION IN DEEP-SEA HYDROTHERMAL PLUMES A DISSERTATION SUBMITTED;ABSTRACT Autotrophic ammonia oxidation has been documented for the first time in deep- sea hydrothermal autotrophic ammonia oxidation at ~ 91 nM d-1 , and potentially produces de novo organic carbon at a rate (0

Luther, Douglas S.

396

Toxicity of ammonia, nitrite, and nitrate to fishes. Book chapter  

Microsoft Academic Search

Ammonia and nitrite are highly toxic to fishes, with ammonia occurring in surface waters more commonly than nitrite. Nitrate is a related compound but is not significantly toxic to fishes. The acute toxicity of ammonia to aquatic organisms is affected by water pH, dissolved oxygen, temperature, concentration fluctuations, degree of salinity, presence of other chemicals, and prior acclimation. The acute

R. C. Russo; R. V. Thurston

1991-01-01

397

Toxicity of Ammonia, Nitrite, and Nitrate to Fishes.  

National Technical Information Service (NTIS)

Ammonia and nitrite are highly toxic to fishes, with ammonia occurring in surface waters more commonly than nitrite. Nitrate is a related compound but is not significantly toxic to fishes. The acute toxicity of ammonia to aquatic organisms is affected by ...

R. C. Russo, R. V. Thurston

1991-01-01

398

Patterns in the release of gaseous ammonia by terrestrial isopods  

Microsoft Academic Search

In the fall and in early spring P. scaber and O. asellus released gaseous ammonia in the form of more or less regularly spaced bursts. In the spring about twice as much ammonia was released by O. asellus than in the fall. In late spring and summer, however, both species released ammonia in a rhythmic fashion, with a maximum at

W. Wieser; G. Schweizer; R. Hartenstein

1969-01-01

399

EVALUATION OF AMMONIA 'FIXATION' COMPONENTS IN ACTUAL REFINERY SOUR WATERS  

EPA Science Inventory

High ammonia concentrations (fixed ammonia) in stripped sour waters from petroleum refining are caused by weak organic acids and both weak and strong sulfur acids. The sulfur acids result from oxidation of sulfides present in sour water. Fixed ammonia can be eliminated by adding ...

400

A SENSITIVE AND AFFORDABLE COMPACT AMMONIA MONITOR - PHASE I  

EPA Science Inventory

Ammonia has an important role in the chemistry of the atmospheric environment and air quality. Ammonia emissions are a major environmental concern, yet they remain poorly quantified. There is a need for a sensitive ammonia instrument to monitor emissions and evaluate their eff...

401

Ammonia-oxidizing archaea involved in nitrogen removal.  

PubMed

Ammonia oxidation is critical to global nitrogen cycling and is often thought to be driven only by ammonia-oxidizing bacteria. The recent finding of new ammonia-oxidizing organisms belonging to the archaeal domain challenges this perception. Two major microbial groups are now believed to be involved in ammonia oxidation: chemolithotrophic ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA). Candidatus "Nitrosopumilus maritimus", the first isolated ammonia-oxidizing archaeon from a tropical marine aquarium tank, representative of the ubiquitous marine group 1 Crenarchaeota, contains putative genes for all three subunits (amoA, amoB, and amoC) of ammonia monooxygenase, the key enzyme responsible for ammonia oxidation. In this article, important concepts of the nitrogen cycle, ammonia oxidation processes, ammonia-oxidizing organisms, and their physiology are described. AOA are found to thrive in various habitats including hot/thermal springs, marine and fresh waters, soils, and wastewater treatment systems, where they may outnumber their counterpart, AOB. Various molecular tools have been applied to study AOB and AOA and determine their abundance and community structure changes from natural and engineered systems. The presence of AOA in activated sludge opens new opportunities for elucidating its role of ammonia removal in wastewater treatment plants and wetlands. Several significant questions related to AOA research have been raised to evoke reader involvement for broadening future studies. PMID:19232671

You, Jia; Das, Atreyee; Dolan, Elizabeth M; Hu, Zhiqiang

2009-04-01

402

The Ammonia Smoke Fountain: An Interesting Thermodynamic Adventure.  

ERIC Educational Resources Information Center

Describes a new demonstration that uses an apparatus like the ammonia-fountain apparatus but with modifications designed to produce ammonium-chloride smoke. This demonstration is easy to perform, interesting to observe, and allows demonstration of the solubility of ammonia in water, the basic nature of ammonia, the acidic nature of hydrogen…

Alexander, M. Dale

1999-01-01

403

USE OF ZEOLITE FOR REMOVING AMMONIA AND AMMONIA-CAUSED TOXCITY IN MARINE TOXICITY IDENTIFCATION EVALUATIONS (TIES)  

EPA Science Inventory

Ammonia occurs in marine waters including effluents, receiving waters, and sediment interstitial waters. At sufficiently high concentrations, ammonia can be toxic to aquatic species. Toxicity identification evaluation (TIE) methods provide researchers with tools for identifyi...

404

Biodegradable plastic reduces ammonia emission during composting  

Microsoft Academic Search

Ammonia is the greatest nuisance odor compound among the exhaust gases that evolve during the composting process, in which raw materials with high concentrations of nitrogen, such as wastewater sludge, are decomposed. In the present study, a reduction of NH3 emission during composting of wastewater sludge was tried by mixing biodegradable plastic into composting raw material. Biodegradable plastic acts as

K Nakasaki; A Ohtaki; H Takano

2000-01-01

405

TREATMENT OF AMMONIA PLANT PROCESS CONDENSATE EFFLUENT  

EPA Science Inventory

The report gives results of an examination of contaminant content and selected treatment techniques for process condensate from seven different ammonia plants. Field tests were performed and data collected on an in-plant steam stripping column with vapor injection into the reform...

406

OPTIMIZED CHEMILUMINESCENCE SYSTEM FOR MEASURING ATMOSPHERIC AMMONIA  

EPA Science Inventory

The optimization and testing of a continuous measurement system for analyzing atmospheric ammonia concentrations (0 to 10 ppb) is described. The measurement system combines an ultra-sensitive chemiluminescence nitric oxide detector, with a thermal converter for NH3 to nitric oxid...

407

Jupiter's ammonia clouds localized or ubiquitous?  

Microsoft Academic Search

Based on the Galileo Near Infrared Imaging (NIMS) data, Baines et al. (2002) have reported that spectrally identifiable ammonia clouds (SIAC) cover less than 1% of Jupiter. Yet, ground-based, satellite and spacecraft observations show that, with the exception of some relatively clear regions (belts, hot spots), clouds exist everywhere on Jupiter. Thermochemical models also predict that Jupiter must be covered

S. K. Atreya; A. S. Wong; T. C. Owen; M. H. Wong

2003-01-01

408

AMMONIA REMOVAL FROM MAMMALIAN CELL CULTURE MEDIUM  

EPA Science Inventory

Metabolites such as ammonia and lactic formed during mammalian cell culture can frequently be toxic to the cells themselves beyond a threshold concentration of the metabolites. ell culture conducted in the presence of such accumulated metabolites is therefore limited in productiv...

409

ACUTE TOXICITY OF AMMONIA TO FATHEAD MINNOWS  

EPA Science Inventory

The acute toxicity of ammonia to fathead minnows Pimephales promelas was measured in 35, 96-hour, flow-through tests. The fish were from both wild and hatchery-reared stocks, and ranged in size from 0.1 to 2.3 g. The 96-hour median lethal concentrations (LC50) ranged from 0.75 to...

410

Feed gas efficiency in ammonia plants  

Microsoft Academic Search

Ammonia producers have continued to increase the performance of their plants as natural gas prices have increased. Maclean et al covered improvements in syn gas preparation procedures and hydrogen recovery from Monsanto's Luling, Louisiana plant. Interest in hydrogen recovery has continued. In this study, a 94% efficiency system is improved to yield 98.7% by changes in temperatures, space velocity, and

Landrum

1984-01-01

411

Radiation chemistry in ammonia-water ices  

SciTech Connect

We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H{sub 2}, N{sub 2}, NO, and N{sub 2}O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete ({approx}97% destroyed) after a fluence of 10{sup 16} ions/cm{sup 2}. Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N{sub 2} and H{sub 2}, which are seen to be ejected from the ice at all temperatures.

Loeffler, M. J. [Astrochemistry Laboratory, NASA GSFC, Code 691, Greenbelt, Maryland 20775 (United States); Laboratory for Atomic and Surface Physics, Engineering Physics, University of Virginia, Charlottesville, Virginia 22904 (United States); Raut, U.; Baragiola, R. A. [Laboratory for Atomic and Surface Physics, Engineering Physics, University of Virginia, Charlottesville, Virginia 22904 (United States)

2010-02-07

412

Radiation chemistry in ammonia-water ices.  

PubMed

We studied the effects of 100 keV proton irradiation on films of ammonia-water mixtures between 20 and 120 K. Irradiation destroys ammonia, leading to the formation and trapping of H(2), N(2), NO, and N(2)O, the formation of cavities containing radiolytic gases, and ejection of molecules by sputtering. Using infrared spectroscopy, we show that at all temperatures the destruction of ammonia is substantial, but at higher temperatures (120 K), it is nearly complete (approximately 97% destroyed) after a fluence of 10(16) ions/cm(2). Using mass spectroscopy and microbalance gravimetry, we measure the sputtering yield of our sample and the main components of the sputtered flux. We find that the sputtering yield depends on fluence. At low temperatures, the yield is very low initially and increases quadratically with fluence, while at 120 K the yield is constant and higher initially. The increase in the sputtering yield with fluence is explained by the formation and trapping of the ammonia decay products, N(2) and H(2), which are seen to be ejected from the ice at all temperatures. PMID:20136323

Loeffler, M J; Raut, U; Baragiola, R A

2010-02-01

413

AMMONIA CONCENTRATIONS IN PINK SALMON, ONCORHYNCHUS GORBUSCHA,  

E-print Network

of metabolism than eggs and early alevins (Bailey et al. 1980) and are undergoing physiological changes to enable them to actively swim and feed rather than reside quietly in the gravel. Salmonid alevins nearing the end of yolk absorption excrete ammonia at a higher rate than eggs or early alevins (Rice and Stokes

414

DRAFT Ammonia Emissions and Animal Agriculture  

Microsoft Academic Search

Nitrogen is found in relatively high levels in all excreted animal manures. It can exist in many chemical forms and can move easily in the environment as a gas in air; as a dissolved constituent of ground or surface water; or in combination with other materials. Ammonia nitrogen (NH3) is of particular concern because of its potential to create odors

Jennifer G. Becker; Robert E. Graves

415

Planar optical waveguide sensor of ammonia  

NASA Astrophysics Data System (ADS)

We describe a novel sensor of ammonia based on a planar optical waveguide made of a thin film of polymer polyimide doped with indicator dye bromocresol purple. The film of dye-doped polyimide demonstrated reversible increase of absorption with a peak near 600 nm in response to presence of ammonia in ambient air. Coupling of input and output optic fibers with the waveguide was done by means of coupling prisms or coupling grooves. The latter configuration has the advantage of low cost, less sensitivity to temperature variation, and the possibility of coupling from both sides of the waveguide. Special experimental setup was built to test the sensor. It included test gas chamber with sealed optic fiber feed-throughs, gas filling line, laser source, photodetector, and signal processing hardware and software. The sensor was capable of detecting 100 ppm of ammonia in air within 8 seconds. Further increase of sensitivity can be achieved by adding more dye dopant to the polymer, increase of the length of the waveguide, and suppression of noise. Overexposure of the sensor to more than 5000 ppm of ammonia led to the saturation of the polymer film and, as a result, significant decrease of sensitivity and increase of the response time. The sensor can be used as low cost component of a distributed optical network of chemical sensors for monitoring presence of hazardous industrial pollutants in air.

Sarkisov, Sergey S.; Curley, Michael J.; Boykin, Courtney; Diggs, Darnell E.; Grote, James G.; Hopkins, Frank K.

2004-12-01

416

8, 54135436, 2008 Ammonia in sulfuric  

E-print Network

.0 License. Atmospheric Chemistry and Physics Discussions The role of ammonia in sulfuric acid ion induced, Department of Physical Sciences, P.O. Box 64, 00014 University of Helsinki, Finland Received: 9 January 2008 on atmospherically relevant cluster structures that makes calculation for large clusters affordable with a good

Boyer, Edmond

417

Progress reported in PET recycling  

SciTech Connect

The Goodyear Polyester Division has demonstrated its ability to break down polyethylene terephthalate (PET) from recycled plastic soft drink bottles and remanufacture the material into PET suitable for containers. Most people are familiar with PET in the form of lightweight, shatter resistant beverage bottles. About 20 percent of these beverage containers currently are being recycled. The recycled PET is currently used in many applications such as carpeting, pillow stuffing, sleeping bag filling, insulation for water heaters and non-food containers. This is the first step of Goodyear's increased efforts to recycle PET from containers into a material suitable for food packing. The project is extremely complex, involving sophisticated understanding of the chemical reactions involved, PET production and the technology testing protocols necessary to design a process that addresses all the technical, safety, and regulatory concerns. The research conducted so far indicated that additional processing beyond simply cleaning the shredded material, called flake, will be required to assure a quality polymer.

Not Available

1989-06-01

418

Text recycling: acceptable or misconduct?  

PubMed

Text recycling, also referred to as self-plagiarism, is the reproduction of an author's own text from a previous publication in a new publication. Opinions on the acceptability of this practice vary, with some viewing it as acceptable and efficient, and others as misleading and unacceptable. In light of the lack of consensus, journal editors often have difficulty deciding how to act upon the discovery of text recycling. In response to these difficulties, we have created a set of guidelines for journal editors on how to deal with text recycling. In this editorial, we discuss some of the challenges of developing these guidelines, and how authors can avoid undisclosed text recycling. PMID:25127654

Harriman, Stephanie; Patel, Jigisha

2014-01-01

419

Disposal, Degradation, and Recycling; Bioplastics  

NSDL National Science Digital Library

Everyone is familiar with plastic waste. We throw away large volumes of it, at home, at school, at work, at fast food restaurants, on vacation. Much of it ends up in the trash. We see some of it as litter along the sides of roads, streams and lakes, and floating up on beaches. We probably recycle some used plastics, although how much depends upon where we live. In many localities, only items produced from PET (polyethylene terephthalate) and HDPE (high-density polyethylene) are collected for recycling. Why don't we recycle more of it? Why not LDPE (low-density polyethylene) and polystyrene? And what happens to it when we do? We'll develop some basic principles in this chapter on some of the avenues that help us follow the U.S. Environmental Protection Agency's advice to "reduce, reuse, recycle."

Teegarden, David

2004-01-01

420

Make Your Own Recycled Paper  

NSDL National Science Digital Library

Students learn how paper is made. Working together, student teams make their own paper. This activity introduces students to recycling; what it is, its value and benefits, and how it affects their lives.

Center For Engineering Educational Outreach

421

Molecular Modeling at Plastic Recycling  

NASA Astrophysics Data System (ADS)

The possibility to model the new materials from recycled, post industrial polymer rejects by molecular modeling methods was investigated by comparison of the results obtained from the simulation process and the experiments.

Martinelli, Laura; Sinesi, Sabino; Toaldo, Alessio Baron; Fermeglia, Maurizio; Posocco, Paola; Szczurek, Tomasz; Kozlowski, Marek

2007-04-01

422

New approaches to recycling tires  

SciTech Connect

Steel-belted radial tires are potentially one of the most recyclable products created by modern industry, although the potential has been barely tapped. Discarded tires pile up at an astonishing rate each year - 234 million in the US and 26 million passenger tire equivalents in Canada. They represent a mother lode of raw material waiting for modern day miners to transform them into recycled rubber, steel, fiber and energy. The tremendous increase in use of steel belted radials since the early 1970s has complicated their recyclability compared to the bias ply tire, but it has also accomplished waste reduction by tripling tire service life. Part one of this report describes processes being developed to convert tires to crumb rubber, as well as some potential uses of recycled rubber. Part two, to appear next month, will examine such uses as rubberized athletic tracks and highway asphalt.

Spencer, R.

1991-03-01

423

National Recycling Directory. Final report  

SciTech Connect

The directory focuses on manufacturers and/or distributors of products made from waste materials. Companies listed in the directory manufacture products which contain some recycled or recovered material. The directory consists of separate sections for the types of recycled materials used: glass, ferrous metals, non-ferrous metals, paper, plastic, rubber, and textiles. The states are listed alphabetically within each subsection, and the companies are listed alphabetically under the state in which they are located.

Not Available

1982-01-01

424

Recycling Policies for Consumer Durables  

Microsoft Academic Search

\\u000a The previous chapter dealt with solid consumption waste and the associated disposal costs. In doing so, we have implicitly\\u000a assumed that the disposal cost function also reflects the recycling of the durable consumption goods (e.g. on p. 89). Of course,\\u000a such a modeling is rather abstract since it makes explicit neither the productivity of the recycled material in the production

Marco Runkel

425

Framework for Building Design Recyclability  

E-print Network

contractors sort waste and transport them to transfer stations or just send all the waste to transfer centers without sorting. 2.2.2 Transfer Stations Regardless of the method used to collect the recyclables, the next leg of their journey is usually... to the use of transfer stations in which the waste is transferred to large-capacity transfer trailers the trailers are then hauled to the landfill. Recyclables collected on site Specific transfer stations Big transfer centers Manufacturing...

Zhang, Fan

2008-01-01

426

Recycling in the Encyclopedia 1  

Microsoft Academic Search

Re-cycling' is the principle that concepts are 're-cycled' rather than duplicated. At the interface between the encyclopedia and the lexicon, this means that a concept may serve both as the meaning of a word and also as part of ordinary non-linguistic cognition; for example, the ordinary concept 'bicycle' which we use in everyday life in classifying experiences is also the

Richard Hudson; Jasper Holmes

427

Key recycling in authentication  

E-print Network

In their seminal work on authentication, Wegman and Carter propose that to authenticate multiple messages, it is sufficient to reuse the same hash function as long as each tag is encrypted with a one-time pad. They argue that because the one-time pad is perfectly hiding, the hash function used remains completely unknown to the adversary. Since their proof is not composable, we revisit it using a composable security framework. It turns out that the above argument is insufficient: if the adversary learns whether a corrupted message was accepted or rejected, information about the hash function is leaked, and after a bounded finite amount of rounds it is completely known. We show however that this leak is very small: Wegman and Carter's protocol is still $\\epsilon$-secure, if $\\epsilon$-almost strongly universal$_2$ hash functions are used. This implies that the secret key corresponding to the choice of hash function can be reused in the next round of authentication without any additional error than this $\\epsilon$. We also show that if the players have a mild form of synchronization, namely that the receiver knows when a message should be received, the key can be recycled for any arbitrary task, not only new rounds of authentication.

Christopher Portmann

2012-02-06

428

AMMONIA CONCENTRATION IN SALTSTONE HEADSPACE SUMMARY REPORT  

SciTech Connect

The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar into Tank 50. Saltstone samples were prepared with an 'MCU' type salt solution spiked with ammonia. The ammonia released from the saltstone was captured and analyzed. The ammonia concentration found in the headspace of samples maintained at 95 C and 1 atm was, to 95% confidence, less than or equal to 3.9 mg/L. Tank 50 is fed by several influent streams. The salt solution from Tank 50 is pumped to the salt feed tank (SFT) in the Saltstone Production Facility (SPF). The premix materials cement, slag and fly ash are blended together prior to transfer to the grout mixer. The premix is fed to the grout mixer in the SPF and the salt solution is incorporated into the premix in the grout mixer, yielding saltstone slurry. The saltstone slurry drops into a hopper and then is pumped to the vault. The Saltstone Facility Documented Safety Analysis (DSA) is under revision to accommodate changes in the Composite Lower Flammability Limit (CLFL) from the introduction of Isopar{reg_sign} L into Tank 50. Waste Solidification-Engineering requested that the Savannah River National Laboratory (SRNL) perform testing to characterize the release of ammonia in curing saltstone at 95 C. The test temperature represents the maximum allowable temperature in the Saltstone Disposal Facility (SDF). Ammonia may be present in the salt solution and premix materials, or may be produced by chemical reactions when the premix and salt solution are combined. A final report (SRNS-STI-2008-00120, Rev. 0) will be issued that will cover in more depth the information presented in this report.

Zamecnik, J; Alex Cozzi, A

2008-09-26

429

Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation  

NASA Astrophysics Data System (ADS)

This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. Pacific Northwest Laboratory (PNL) researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH4(+)). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

Anheier, N. C., Jr.; McDonald, C. E.; Cuta, J. M.; Cuta, F. M.; Olsen, K. B.

1995-05-01

430

Ammonia and ammonium hydroxide sensors for ammonia/water absorption machines: Literature review and data compilation  

SciTech Connect

This report describes an evaluation of various sensing techniques for determining the ammonia concentration in the working fluid of ammonia/water absorption cycle systems. The purpose of this work was to determine if any existing sensor technology or instrumentation could provide an accurate, reliable, and cost-effective continuous measure of ammonia concentration in water. The resulting information will be used for design optimization and cycle control in an ammonia-absorption heat pump. PNL researchers evaluated each sensing technology against a set of general requirements characterizing the potential operating conditions within the absorption cycle. The criteria included the physical constraints for in situ operation, sensor characteristics, and sensor application. PNL performed an extensive literature search, which uncovered several promising sensing technologies that might be applicable to this problem. Sixty-two references were investigated, and 33 commercial vendors were identified as having ammonia sensors. The technologies for ammonia sensing are acoustic wave, refractive index, electrode, thermal, ion-selective field-effect transistor (ISFET), electrical conductivity, pH/colormetric, and optical absorption. Based on information acquired in the literature search, PNL recommends that follow-on activities focus on ISFET devices and a fiber optic evanescent sensor with a colormetric indicator. The ISFET and fiber optic evanescent sensor are inherently microminiature and capable of in situ measurements. Further, both techniques have been demonstrated selective to the ammonium ion (NH{sub 4}{sup +}). The primary issue remaining is how to make the sensors sufficiently corrosion-resistant to be useful in practice.

Anheier, N.C. Jr.; McDonald, C.E.; Cuta, J.M.; Cuta, F.M.; Olsen, K.B.

1995-05-01

431

Septic wastewater treatment using recycled rubber particles as biofiltration media.  

PubMed

Performance of the laboratory-scale recycled rubber particles (RRP) biofilter was compared to a conventional gravel system and a peat biofilter for treatment of septic tank effluent. During the study, the RRP biofilter provided similar or better performance than other systems in terms of organic removal and hydraulic capacity. After the start-up period, RRP biofilter achieved removal efficiencies for BOD5, total suspended solids (TSS), ammonia nitrogen of 96%, 93%, and 90%, respectively, over the range of hydraulic loading rates of 57-204 L/m2/d. On the other hand, the peat biofilter failed hydraulically and the gravel system showed high TSS concentrations in the effluent. RRP provided high surface area and sufficient time for biological treatment. In addition, RRP was observed to provide ammonia adsorption capacity. The results showed that RRP has the potential to be used as substitutes for natural aggregate such as gravel in septic system drainfields. The RRP biofilter can be used as alternative septic systems for the sites where an existing septic system has failed or site conditions, such as high groundwater table or small lot size, are not suitable for the installation of conventional septic systems. PMID:24645443

Oh, Jin Hwan; Park, Jaeyoung; Ellis, Timothy G

2014-01-01

432

The microstructure of Portland cement-based materials: Computer simulation and percolation theory  

SciTech Connect

Portland cement-based materials are usually composites, where the matrix consists of portland cement paste. Cement paste is a material formed from the hydration reaction of portland cement, usually a calcium silicate material, with water. The microstructure of cement paste changes drastically over a time period of about one week, with slower changes occurring over subsequent weeks to months. The effect of this hydration process on the changing microstructure can be represented using computer simulation techniques applied to three dimensional digital image-based models. Percolation theory can be used to understand the evolving microstructure in terms of the three percolation thresholds that are of importance in the cement past microstructure: the set point, capillary porosity percolation, and the percolation of the C-S-H phase.

Garboczi, E.J.; Bentz, D.P. [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1998-12-31

433

Percolation line, response functions, and Voronoi polyhedra analysis in supercritical water  

E-print Network

The problem of a physical relevance (meaning) of percolation in supercritical fluids is addressed considering a primitive model of water. Two different criteria, physical and configurational, are used for the cluster definition in Monte Carlo simulations over a range of pressures to determine the percolation line and skewness, and a theoretical analytic equation of state is used to evaluate response functions. It is found that both criteria yield practically the same percolation line. However, unlike the findings for simple fluids, the loci of the response function extrema exhibit density/pressure dependence quite different from that of the percolation line. The only potential coincidence between the loci of the extrema of a thermodynamic property and a detectable structural change is found for the coefficient of isothermal compressibility and Voronoi neighbors distribution skewness maximum.

J. Skvor; I. Nezbeda

2012-07-13

434

Transmission of packets on a hierarchical network: Avalanches, statistics and explosive percolation  

E-print Network

We discuss transport on load bearing branching hierarchical networks which can model diverse systems which can serve as models of river networks, computer networks, respiratory networks and granular media. We study avalanche transmissions and directed percolation on these networks, and on the V lattice, i.e., the strongest realization of the lattice. We find that typical realizations of the lattice show multimodal distributions for the avalanche transmissions, and a second order transition for directed percolation. On the other hand, the V lattice shows power - law behavior for avalanche transmissions, and a first order (explosive) transition to percolation. The V lattice is thus the critical case of hierarchical networks. We note that small perturbations to the V lattice destroy the power-law behavior of the distributions, and the first order nature of the percolation. We discuss the implications of our results.

Gupte, Neelima

2014-01-01

435

Bond percolation on a dilute lattice with short and long range correlations: A numerical simulation  

NASA Astrophysics Data System (ADS)

The quenched percolation problem on a dilute lattice with a given random structure of vacancies is analyzed by numerical simulations in d=2 and d=3. The distribution of the sites of the dilute lattice satisfies the static structure factor S(k)=ak-2+b and contains short range (a=0) and long range (a>>0) effects, respectively. The numerical simulation shows that the critical behavior of the percolation on lattices with short range correlations (a=0) is equivalent to the usual percolation on a regular lattice, whereas the percolation on a lattice with long range correlations shows a characteristic change of the universality class. In particular, a critical exponent ? was detected, which is significantly greater than the usual exponent ?random.

Bauerschäfer, Ulf; Schulz, Michael

1996-08-01

436

Determination of the Controls on Permeability and Transport in Shale by Use of Percolation Models  

E-print Network

this information. While a great deal is known about the connectivity in conventional sandstone systems, little is understood about the connectivity and its resultant properties within shale systems. Percolation theory is a method to describe the global properties...

Chapman, Ian

2012-10-19

437

The Effect of Gas Bubble Percolation on the Carbonaceous Mesophase Produced from Acenaphthylene.  

National Technical Information Service (NTIS)

A study of mesophase formation in acenaphthylene was undertaken in an attempt to determine the effect of gas bubble percolation during pyrolysis on the mesophase microstructure. Samples of acenaphythylene approximately 20 g in size were pyrolyzed in test ...

D. O. Rester

1976-01-01

438

Percolation clusters as teaching aid for Monte Carlo simulation and critical exponents  

NSDL National Science Digital Library

The author discusses a geometrical phase transition involving percolation clusters. This continuous phase transition can be easily simulated on a computer and is analogous to the critical in the Ising model.

Stauffer, D.

2011-06-29

439

Effect of Percolation on the Cubic Susceptibility of Metal Nanoparticle Composites  

NASA Technical Reports Server (NTRS)

Generalized two-dimensional and three-dimensional Maxwell Garnett and Bruggeman geometries reveal that a sign reversal in the cubic susceptibility occurs for metal nanoparticle composites near the percolation threshold.

Smith, David D.; Bender, Matthew W.; Boyd, Robert W.

1998-01-01

440

Correlated percolation in island-forming processes: Analysis of cooperative filling on a square lattice  

NASA Astrophysics Data System (ADS)

Percolation transitions are analyzed for correlated distributions of occupied sites created by irreversible cooperative filling on a square lattice. Filling can be either autocatalytic, corresponding to island formation, or autoinhibitory. Here percolation problems for occupied and unoccupied clusters are generally distinct. Our discussion focuses on the influence of island formation (associated with correlation lengths of many lattice vectors), and of island perimeter roughness, on percolation. We also discuss the transition to continuum percolation problems as the ratio of island growth to nucleation rates, and thus the average island size, diverges. Some direct analysis of occupied cluster structure is provided, the connection with correlated animals is made, and correlated spreading and walking algorithms are suggested for direct generation of clusters and their perimeters.

Sanders, D. E.; Evans, J. W.

1988-10-01

441

Diffusion of test particles in stochastic magnetic fields in the percolative regime  

SciTech Connect

For stochastic magnetic flux functions with percolative contours the test particle transport is investigated. The calculations make use of the stochastic Liouville approach. They start from the so-called A-Langevin equations, including stochastic magnetic field components and binary collisions. Using the decorrelation trajectory method, a relation between the Lagrangian velocity correlation function and the Eulerian magnetic field correlation is derived and introduced into the Green-Kubo formalism. Finite Larmor radius effects are included. Interesting results are presented in the percolation regime corresponding to high Kubo numbers. Previous results are found to be limiting cases for small Kubo numbers. For different percolative scenarios the diffusion is analyzed and strong influences of the percolative structures on the transport scaling are found. The finite Larmor radius effects are discussed in detail. Numerical simulations of the A-Langevin equation confirm the semianalytical predictions.

Neuer, Marcus; Spatschek, Karl H. [Institut fuer Theoretische Physik I, Heinrich-Heine-Universitaet Duesseldorf, D-40225 Duesseldorf (Germany)

2006-09-15

442

[Isolation of an aboriginal bacterial community capable of utilizing cyanide, thiocyanate, and ammonia from metallurgical plant wastewater].  

PubMed

An aboriginal bacterial community capable of degrading cyanide (10 mg/l) and thiocyanate (2 g/l) and eliminating ammonia (120 mg/l) had been isolated from recycled water samples after blast-furnace gas purification of a metallurgical plant wastewater. It was shown that the optimal conditions for this bacterial community were as follows: temperature, 34 degrees C; pH, 8.8-9.0; available organic matter concentration (glucose equivalent), 5 g/l; and dissolved O2 concentration, 8-10 mg/l. This aboriginal community was formed by the bacteria belonging to the genus Pseudomonas. PMID:18822775

Grigor'eva, N V; Smirnova, Iu V; Terekhova, S V; Karava?ko, G I

2008-01-01

443

RDS and Recycling Waste Diversion in Food Prep  

E-print Network

RDS and Recycling Waste Diversion in Food Prep Setting #12;Why Recycle? Recycling saves resources Recycling one ton of paper saves 17 trees! Recycling saves energy Recycling one aluminum can saves enough energy to power a television for 3 hours! Recycling is easy There are 4 waste categories here at UM

Awtar, Shorya

444

50 Simple Things Kids Can Do To Recycle. California Edition.  

ERIC Educational Resources Information Center

This book provides 50 recycling ideas for children and features Recycle Rex, the state of California's "spokesdinosaur" for recycling. An introduction contains recycling background information on waste disposal options and reducing, reusing, and recycling. Recycling suggestions are divided into nine sections: (1) "Learn What You Can Recycle"…

Javna, John

445

Proposal for a CFT interpretation of Watts' differential equation for percolation  

E-print Network

G. M. T. Watts derived that in two dimensional critical percolation the crossing probability Pi_hv satisfies a fifth order differential equation which includes another one of third order whose independent solutions describe the physically relevant quantities 1, Pi_h, Pi_hv. We will show that this differential equation can be derived from a level three null vector condition of a rational c=-24 CFT and motivate how this solution may be fitted into known properties of percolation.

Michael A. I. Flohr; Annekathrin Mueller-Lohmann

2005-07-21

446

Percolation-enhanced generation of terahertz pulses by optical rectification on ultrathin gold films.  

PubMed

Emission of pulses of electromagnetic radiation in the terahertz range is observed when ultrathin gold films on glass are illuminated with femtosecond near-IR laser pulses. A distinct maximum is observed in the emitted terahertz amplitude from films of average thickness just above the percolation threshold. Our measurements suggest that the emission is through a second-order nonlinear optical rectification process, enhanced by the excitation of localized surface plasmon hot spots on the percolated metal film. PMID:21725483

Ramakrishnan, Gopakumar; Planken, Paul C M

2011-07-01

447

Flow, diffusion, and thermal convection in percolation clusters: NMR experiments and numerical FEM/FVM simulations.  

PubMed

Percolation objects were fabricated based on computer-generated, two- or three-dimensional templates. Random-site, semi-continuous swiss cheese, and semi-continuous inverse swiss-cheese percolation models above the percolation threshold were considered. The water-filled pore space was investigated by NMR imaging and, in the presence of a pressure gradient, NMR velocity mapping. The fractal dimension, the correlation length, and the percolation probability were evaluated both from the computer-generated templates and the corresponding NMR spin density maps. Based on velocity maps, the percolation backbones were determined. The fractal dimension of the backbones turned out to be smaller than that of the complete cluster. As a further relation of interest, the volume-averaged velocity was calculated as a function of the probe volume radius. In a certain scaling window, the resulting dependence can be represented by a power law the exponent of which was not yet considered in the theoretical literature. The experimental results favorably compare to computer simulations based on the finite-element method (FEM) or the finite-volume method (FVM). Percolation theory suggests a relationship between the anomalous diffusion exponent and the fractal dimension of the cluster, i.e., between a dynamic and a structural parameter. We examined interdiffusion between two compartments initially filled with H2O and D2O, respectively, by proton imaging. The results confirm the theoretical expectation. As a third transport mechanism, thermal convection in percolation clusters of different porosities was studied with the aid of NMR velocity mapping. The velocity distribution is related to the convection roll size distribution. Corresponding histograms consist of a power law part representing localized rolls, and a high-velocity cut-off for cluster-spanning rolls. The maximum velocity as a function of the porosity clearly visualizes the percolation transition. PMID:11445311

Kimmich, R; Klemm, A; Weber, M

2001-01-01

448

Heat Tracing Percolation in Managed Aquifer Recharge Facilities using Fiber Optic Distributed Temperature Sensing  

NASA Astrophysics Data System (ADS)

Percolation rates in Managed Aquifer Rechage (MAR) facilities, such as recharge basins and stream channels, can vary widely through both time and space. Natural variations in sediment hydraulic conductivity can create 'dead zones' in which percolation rates are negligible. Clogging is a constant problem, leading to decays in facility percolation rates . Measuring percolation rate variations is important for management, maintenance, and remediation of surface MAR facilities We have used Fiber Optic Distributed Temperature Sensing (FODTS) to monitor percolation in two very different recharge facilities. The first is a small (2 ha) nearly round recharge basin of homogeneous sediment type in which water balance can be closely monitored. The second is a long narrow river channel separated from an active river by a levee. The alluvial sediment in the river channel varies widely in texture and water balance is difficult to monitor independently. Both facilities were monitored by trenching in fiber optic cable and measuring the propagation rate of the diurnal temperature oscillations carried downward with infiltrating water. In this way, heat was used as a tracer of percolation rates along the section defined by the trenched cable (400 and 1600 m, respectively). We were able to confirm the FODTS measurements of percolation in the recharge basin and demonstrate its wide applicability in the river channel. Results from the measurements have been used to understand both the hydraulic behavior of percolation in the facilities and to make management decisions regarding facility operations and the potential need for additional surface sediment remediation. Estimation of specific discharge (m/day) through the basin using the wavelet method. Basin stage is shown above

Becker, M.; Ellis, W.; Bauer, B.; Hutchinson, A.

2013-12-01

449

Bootstrap Percolation on Complex Networks with Community Structure  

E-print Network

Real complex networks usually involve community structure. How innovation and new products spread on social networks which have internal structure is a practically interesting and fundamental question. In this paper we study the bootstrap percolation on a single network with community structure, in which we initiate the bootstrap process by activating different fraction of nodes in each community. A previously inactive node transfers to active one if it detects at least $k$ active neighbors. The fraction of active nodes in community $i$ in the final state $S_i$ and its giant component size $S_{gci}$ are theoretically obtained as functions of the initial fractions of active nodes $f_i$. We show that such functions undergo multiple discontinuous transitions; The discontinuous jump of $S_i$ or $S_{gci}$ in one community may trigger a simultaneous jump of that in the other, which leads to multiple discontinuous transitions for the total fraction of active nodes $S$ and its associated giant component size $S_{gc}$...

Chong, Wu; Rui, Zhang; Liujun, Chen; Jiawei, Chen; Xiaobin, Li; Yanqing, Hu

2014-01-01

450

Percolation on shopping and cashback electronic commerce networks  

NASA Astrophysics Data System (ADS)

Many realistic networks live in the form of multiple networks, including interacting networks and interdependent networks. Here we study percolation properties of a special kind of interacting networks, namely Shopping and Cashback Electronic Commerce Networks (SCECNs). We investigate two actual SCECNs to extract their structural properties, and develop a mathematical framework based on generating functions for analyzing directed interacting networks. Then we derive the necessary and sufficient condition for the absence of the system-wide giant in- and out- component, and propose arithmetic to calculate the corresponding structural measures in the sub-critical and supercritical regimes. We apply our mathematical framework and arithmetic to those two actual SCECNs to observe its accuracy, and give some explanations on the discrepancies. We show those structural measures based on our mathematical framework and arithmetic are useful to appraise the status of SCECNs. We also find that the supercritical regime of the whole network is maintained mainly by hyperlinks between different kinds of websites, while those hyperlinks between the same kinds of websites can only enlarge the sizes of in-components and out-components.

Fu, Tao; Chen, Yini; Qin, Zhen; Guo, Liping

2013-06-01

451

Percolation on fitness-dependent networks with heterogeneous resilience  

NASA Astrophysics Data System (ADS)

The ability to understand the impact of adversarial processes on networks is crucial to various disciplines. The objects of study in this article are fitness-driven networks. Fitness-dependent networks are fully described by a probability distribution of fitness and an attachment kernel. Every node in the network is endowed with a fitness value and the attachment kernel translates the fitness of two nodes into the probability that these two nodes share an edge. This concept is also known as mutual attractiveness. In the present article, fitness does not only serve as a measure of attractiveness, but also as a measure of a node's robustness against failure. The probability that a node fails increases with the number of failures in its direct neighborhood and decreases with higher fitness. Both static and dynamic network models are considered. Analytical results for the percolation threshold and the occupied fraction are derived. One of the results is that the distinction between the dynamic and the static model has a profound impact on the way failures spread over the network. Additionally, we find that the introduction of mutual attractiveness stabilizes the network compared to a pure random attachment.

Hoppe, K.; Rodgers, G. J.

2014-07-01

452

Modeling fractal cities using the correlated percolation model.  

NASA Astrophysics Data System (ADS)

Cities grow in a way that might be expected to resemble the growth of two-dimensional aggregates of particles, and this has led to recent attempts to model urban growth using ideas from the statistical physics of clusters. In particular, the model of diffusion limited aggregation (DLA) has been invoked to rationalize the apparently fractal nature of urban morphologies(M. Batty and P. Longley, Fractal Cities) (Academic, San Diego, 1994). The DLA model predicts that there should exist only one large fractal cluster, which is almost perfectly screened from incoming 'development units' (representing, for example, people, capital or resources), so that almost all of the cluster growth takes place at the tips of the cluster's branches. We show that an alternative model(H. A. Makse, S. Havlin, H. E. Stanley, Nature 377), 608 (1995), in which development units are correlated rather than being added to the cluster at random, is better able to reproduce the observed morphology of cities and the area distribution of sub-clusters ('towns') in an urban system, and can also describe urban growth dynamics. Our physical model, which corresponds to the correlated percolation model in the presence of a density gradient, is motivated by the fact that in urban areas development attracts further development. The model offers the possibility of predicting the global properties (such as scaling behavior) of urban morphologies.

Makse, Hernán A.; Havlin, Shlomo; Stanley, H. Eugene

1996-03-01

453

Anisotropy in Fracking: A Percolation Model for Observed Microseismicity  

NASA Astrophysics Data System (ADS)

Hydraulic fracturing (fracking), using high pressures and a low viscosity fluid, allow the extraction of large quantiles of oil and gas from very low permeability shale formations. The initial production of oil and gas at depth leads to high pressures and an extensive distribution of natural fractures which reduce the pressures. With time these fractures heal, sealing the remaining oil and gas in place. High volume fracking opens the healed fractures allowing the oil and gas to flow to horizontal production wells. We model the injection process using invasion percolation. We use a 2D square lattice of bonds to model the sealed natural fractures. The bonds are assigned random strengths and the fluid, injected at a point, opens the weakest bond adjacent to the growing cluster of opened bonds. Our model exhibits burst dynamics in which the clusters extend rapidly into regions with weak bonds. We associate these bursts with the microseismic activity generated by fracking injections. A principal object of this paper is to study the role of anisotropic stress distributions. Bonds in the y-direction are assigned higher random strengths than bonds in the x-direction. We illustrate the spatial distribution of clusters and the spatial distribution of bursts (small earthquakes) for several degrees of anisotropy. The results are compared with observed distributions of microseismicity in a fracking injection. Both our bursts and the observed microseismicity satisfy Gutenberg-Richter frequency-size statistics.

Norris, J. Quinn; Turcotte, Donald L.; Rundle, John B.

2014-08-01

454

Field theory of directed percolation with long-range spreading.  

PubMed

It is well established that the phase transition between survival and extinction in spreading models with short-range interactions is generically associated with the directed percolation (DP) universality class. In many realistic spreading processes, however, interactions are long ranged and well described by Lévy flights-i.e., by a probability distribution that decays in d dimensions with distance r as r;{-d-sigma} . We employ the powerful methods of renormalized field theory to study DP with such long-range Lévy-flight spreading in some depth. Our results unambiguously corroborate earlier findings that there are four renormalization group fixed points corresponding to, respectively, short-range Gaussian, Lévy Gaussian, short-range, and Lévy DP and that there are four lines in the (sigma,d) plane which separate the stability regions of these fixed points. When the stability line between short-range DP and Lévy DP is crossed, all critical exponents change continuously. We calculate the exponents describing Lévy DP to second order in an epsilon expansion, and we compare our analytical results to the results of existing numerical simulations. Furthermore, we calculate the leading logarithmic corrections for several dynamical observables. PMID:19256812

Janssen, Hans-Karl; Stenull, Olaf

2008-12-01

455

Dimensional dependence of phase transitions in explosive percolation  

NASA Astrophysics Data System (ADS)

To understand the dependence of phase-transition natures in explosive percolations on space dimensions, the number ncut of cutting bonds (sites) and the fractal dimension dCSC of the critical spanning cluster (CSC) for the six different models introduced in Phys. Rev. E 86, 051126 (2012), 10.1103/PhysRevE.86.051126 are studied on two- and three-dimensional lattices. It is found that ncut(L??)=1 for the intrabond-enhanced models and the site models on the two-dimensional square lattice with lattice size L. In contrast, ncut for the intrabond-suppressed models scales as ncut?Ldcut with dcut=1. dCSC=2.00(1) is obtained for the intrabond-enhanced models and the site models, while dCSC=1.96(1)(<2) is obtained for the intrabond-suppressed models in two dimensions (2D). These results strongly support that the intrabond-enhanced models and the site models undergo the discontinuous transition in 2D, while the intrabond-suppressed models do the continuous transition in 2D. On the three-dimensional cubic lattice, we find that dcut>0 and dCSC=2.8(1)(<3) for all six models, which indicates that the models undergo the continuous transition. Based on the finite-size scaling analyses of mean cluster size and order parameter, all six models in 3D show nearly the same critical phenomena within numerical errors.

Choi, Woosik; Chae, Huiseung; Yook, Soon-Hyung; Kim, Yup

2014-08-01

456

Combustion Byproducts Recycling Consortium  

SciTech Connect

The Combustion Byproducts Recycling Consortium (CBRC) program was developed as a focused program to remove and/or minimize the barriers for effective management of over 123 million tons of coal combustion byproducts (CCBs) annually generated in the USA. At the time of launching the CBRC in 1998, about 25% of CCBs were beneficially utilized while the remaining was disposed in on-site or off-site landfills. During the ten (10) year tenure of CBRC (1998-2008), after a critical review, 52 projects were funded nationwide. By region, the East, Midwest, and West had 21, 18, and 13 projects funded, respectively. Almost all projects were cooperative projects involving industry, government, and academia. The CBRC projects, to a large extent, successfully addressed the problems of large-scale utilization of CCBs. A few projects, such as the two Eastern Region projects that addressed the use of fly ash in foundry applications, might be thought of as a somewhat smaller application in comparison to construction and agricultural uses, but as a novel niche use, they set the stage to draw interest that fly ash substitution for Portland cement might not attract. With consideration of the large increase in flue gas desulfurization (FGD) gypsum in response to EPA regulations, agricultural uses of FGD gypsum hold promise for large-scale uses of a product currently directed to the (currently stagnant) home construction market. Outstanding achievements of the program are: (1) The CBRC successfully enhanced professional expertise in the area of CCBs throughout the nation. The enhanced capacity continues to provide technology and information transfer expertise to industry and regulatory agencies. (2) Several technologies were developed that can be used immediately. These include: (a) Use of CCBs for road base and sub-base applications; (b) full-depth, in situ stabilization of gravel roads or highway/pavement construction recycled materials; and (c) fired bricks containing up to 30%-40% F-fly ash. Some developed technologies have similar potential in the longer term. (3) Laboratory studies have been completed that indicate that much higher amounts of fly ash could be added in cement-concrete applications under some circumstances. This could significantly increase use of fly ash in cement-concrete applications. (4) A study of the long-term environmental effects of structural fills in a surface mine in Indiana was completed. This study has provided much sought after data for permitting large-volume management options in both beneficial as well as non-beneficial use settings. (5) The impact of CBRC on CCBs utilization trends is difficult to quantify. However it is fair to say that the CBRC program had a significant positive impact on increased utilization of CCBs in every region of the USA. Today, the overall utilization of CCBs is over 43%. (6) CBRC-developed knowledge base led to a large number of other projects completed with support from other sources of funding. (7) CBRC research has also had a large impact on CCBs management across the globe. Information transfer activities and visitors from leading coal producing countries such as South Africa, Australia, England, India, China, Poland, Czech Republic and Japan are truly noteworthy. (8) Overall, the CBRC has been a truly successful, cooperative research program. It has brought together researchers, industry, government, and regulators to deal with a major problem facing the USA and other coal producing countries in the world.

Paul Ziemkiewicz; Tamara Vandivort; Debra Pflughoeft-Hassett; Y. Paul Chugh; James Hower

2008-08-31

457

Flow through percolation clusters: NMR velocity mapping and numerical simulation study  

NASA Astrophysics Data System (ADS)

Three- and (quasi-)two-dimensional percolation objects have been fabricated based on Monte Carlo generated templates. The object size was up to 12 cm (300 lattice sites) in each dimension. Random site, semicontinuous swiss-cheese, and semicontinuous inverse swiss-cheese percolation models above the percolation threshold were considered. The water-filled pore space was investigated by nuclear magnetic resonance (NMR) imaging and, after exerting a pressure gradient, by NMR velocity mapping. The spatial resolutions of the fabrication process and the NMR experiments were 400 ?m and better than 300 ?m, respectively. The experimental velocity resolution was 60 ?m/s. The fractal dimension, the correlation length, and the percolation probability can be evaluated both from the computer generated templates and the corresponding NMR spin density maps. Based on velocity maps, the percolation backbones were determined. The fractal dimension of the backbones turned out to be smaller than that of the complete cluster. As a further relation of interest, the volume-averaged velocity was calculated as a function of the probe volume radius. In a certain scaling window, the resulting dependence can be represented by a power law, the exponent of which was not yet considered in the theoretical literature. The experimental results favorably compare to computer simulations based on the finite-element method (FEM) or the finite-volume method (FVM). This demonstrates that NMR microimaging as well as FEM/FVM simulations reliably reflect transport features in percolation clusters.

Klemm, Andreas; Kimmich, Rainer; Weber, Markus

2001-04-01

458

Flow through percolation clusters: NMR velocity mapping and numerical simulation study.  

PubMed

Three- and (quasi-)two-dimensional percolation objects have been fabricated based on Monte Carlo generated templates. The object size was up to 12 cm (300 lattice sites) in each dimension. Random site, semicontinuous swiss-cheese, and semicontinuous inverse swiss-cheese percolation models above the percolation threshold were considered. The water-filled pore space was investigated by nuclear magnetic resonance (NMR) imaging and, after exerting a pressure gradient, by NMR velocity mapping. The spatial resolutions of the fabrication process and the NMR experiments were 400 microm and better than 300 microm, respectively. The experimental velocity resolution was 60 microm/s. The fractal dimension, the correlation length, and the percolation probability can be evaluated both from the computer generated templates and the corresponding NMR spin density maps. Based on velocity maps, the percolation backbones were determined. The fractal dimension of the backbones turned out to be smaller than that of the complete cluster. As a further relation of interest, the volume-averaged velocity was calculated as a function of the probe volume radius. In a certain scaling window, the resulting dependence can be represented by a power law, the exponent of which was not yet considered in the theoretical literature. The experimental results favorably compare to computer simulations based on the finite-element method (FEM) or the finite-volume method (FVM). This demonstrates that NMR microimaging as well as FEM/FVM simulations reliably reflect transport features in percolation clusters. PMID:11308855

Klemm, A; Kimmich, R; Weber, M

2001-04-01

459

k-core (bootstrap) percolation on complex networks: Critical phenomena and nonlocal effects  

E-print Network

We develop the theory of the k-core (bootstrap) percolation on uncorrelated random networks with arbitrary degree distributions. We show that the k-core percolation is an unusual, hybrid phase transition with a jump emergence of the k-core as at a first order phase transition but also with a critical singularity as at a continuous transition. We describe the properties of the k-core, explain the meaning of the order parameter for the k-core percolation, and reveal the origin of the specific critical phenomena. We demonstrate that a so-called ``corona'' of the k-core plays a crucial role (corona is a subset of vertices in the k-core which have exactly k neighbors in the k-core). It turns out that the k-core percolation threshold is at the same time the percolation threshold of finite corona clusters. The mean separation of vertices in corona clusters plays the role of the correlation length and diverges at the critical point. We show that a random removal of even one vertex from the k-core may result in the collapse of a vast region of the k-core around the removed vertex. The mean size of this region diverges at the critical point. We find an exact mapping of the k-core percolation to a model of cooperative relaxation. This model undergoes critical relaxation with a divergent rate at some critical moment.

A. V. Goltsev; S. N. Dorogovtsev; J. F. F. Mendes

2006-02-26

460

Biogeochemical Recycling on Aerosol Particles  

NASA Astrophysics Data System (ADS)

Trace elements are recycled on sea-salt particles that are produced and later re-deposited in the surface ocean. This recycling process involves aluminum, iron, and other elements commonly associated with mineral dust. Non-crustal Al can amount to as much as ~ 30% of the total aerosol Al at Bermuda, but this occurs only during a few months of the year when the dust concentrations and deposition rates are low. Simple model calculations suggest that ~15 to 20% of the total Al dry deposition during December and January can be attributed to recycled sea salt, but when dust concentrations are higher, recycling accounts for only ~ 1% of the Al dry deposition. Non-crustal/non-sea salt (NC/NSS) sources account for > 70% of the aerosol Sb, Se, V, and Zn, but differences in the dry deposition velocities for particles of different sizes are such that the amount of Sb and Se recycled on sea spray approaches or exceeds their new inputs to the open ocean from dust and the NC/NSS sources. More recently, recycling on aerosol particles has been found to occur in other environments, including the deserts in the southwestern USA. In this case, the recycling of radionuclides released during nuclear weapons tests many years ago occurs via the resuspension of contaminated soil particles. Studies conducted near Carlsbad, NM have shown that the temporal variability in ^{239,240}Pu and ^{241}Am activities tracks that of Al, a mineral dust indictor, in aerosol samples. Analyses of soil samples from various sites have shown that plutonium is released from the particles by chemical procedures developed for removing iron oxides from mineral particles; this implies that the dust/plutonium relationship is mediated by iron oxides.

Arimoto, R.; Stewart, B.; Khaing, H.; Tatro, D. P.

2006-12-01

461

Recycling of plastics in Germany  

SciTech Connect

This article deals with the waste management of post-consumer plastics in Germany and its potential to save fossil fuels and reduce CO{sub 2} emissions. Since most experience is available for packaging, the paper first gives an overview of the legislative background and the material flows for this sector. Then recycling and recovery processes for plastics waste from all sectors are assessed in terms of their contribution to energy saving and CO{sub 2} abatement. Practically all the options studied show a better performance than waste treatment in an average incinerator which has been chosen as the reference case. High ecological benefits can be achieved by mechanical recycling if virgin polymers are substituted. The paper then presents different scenarios for managing plastic waste in Germany in 1995: considerable savings can be made by strongly enhancing the efficiency of waste incinerators. Under these conditions the distribution of plastics waste among mechanical recycling, feedstock recycling and energy recovery has a comparatively mall impact on the overall results. The maximum savings amount to 74 PJ of energy, i.e, 9% of the chemical sector energy demand in 1995 and 7.0 Mt CO{sub 2}, representing 13% of the sector's emissions. The assessment does not support a general recommendation of energy recovery due to the large difference between the German average and the best available municipal waste-to-energy facilities and also due to new technological developments in the field of mechanical recycling.

Thienen, N. von; Patel, M.

1999-07-01

462

An intercomparison of five ammonia measurement techniques  

NASA Technical Reports Server (NTRS)

Results obtained from five techniques for measuring gas-phase ammonia at low concentration in the atmosphere are compared. These methods are: (1) a photofragmentation/laser-induced fluorescence (PF/LIF) instrument; (2) a molybdenum oxide annular denuder sampling/chemiluminescence detection technique; (3) a tungsten oxide denuder sampling/chemiluminescence detection system; (4) a citric-acid-coated denuder sampling/ion chromatographic analysis (CAD/IC) method; and (5) an oxalic-acid-coated filter pack sampling/colorimetric analysis method. It was found that two of the techniques, the PF/LIF and the CAD/IC methods, measured approximately 90 percent of the calculated ammonia added in the spiking tests and agreed very well with each other in the ambient measurements.

Williams, E. J.; Sandholm, S. T.; Bradshaw, J. D.; Schendel, J. S.; Langford, A. O.; Quinn, P. K.; Lebel, P. J.; Vay, S. A.; Roberts, P. D.; Norton, R. B.

1992-01-01

463

Was early Mars warmed by ammonia?  

NASA Astrophysics Data System (ADS)

Runoff channels and valley networks present on ancient, heavily cratered Martian terrain suggests that the climate of Mars was originally warm and wet. One explanation for the formation of these channels is that the surface was warmed by the greenhouse effect of a dense, CO2 atmosphere. However, recent work shows that this theory is not consistent for the early period of the solar system. One way to increase the surface temperature predicted is to assume that other greenhouse gases were present in Mars' atmosphere in addition to CO2 and H2O. This possible gas is ammonia, NH3. If ammonia was present in sufficient quantities, it could have raised the surface temperature to 273 K. An adequate source would have been volcanic outgassing if the NH3 produced was shielded from photolysis by an ultraviolet light absorber.

Kasting, J. F.; Brown, L. L.; Acord, J. M.; Pollack, J. B.

1992-12-01

464

California's ammonia emissions have been drastically underestimated  

NASA Astrophysics Data System (ADS)

In California, Los Angeles and the Central Valley often have atmospheric concentrations of particulate matter that exceed the U.S. Environmental Protection Agency's health guidelines. In the air, chemical reactions between ammonia, nitrogen oxides, and sulfur oxides can create inorganic aerosols like ammonium nitrate and ammonium sulfate. With their small particle sizes, these compounds can be dangerous to breathe, particularly for those with respiratory problems.

Schultz, Colin

2014-08-01

465

Diverse microbial species survive high ammonia concentrations  

NASA Astrophysics Data System (ADS)

Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

2012-04-01

466

Metal-ammonia reduction of triphenylene  

SciTech Connect

In the reaction of polynuclear aromatic hydrocarbons with alkali metals in liquid ammonia to produce hydroaromatics, it has been found that in certain instances protonation does not occur at the calculated position of highest electron density but rather at a position to produce the most stable monoanion. The isolation of a number of new and interesting hydrocarbons produced by this reaction are reported herein. UV- and NMR-spectral studies were used to determine the structures of the product compounds.

Marcinow, Z.; Sygula, A.; Rabideau, P.W.

1988-07-22

467

Ammonia transfer across rotating joints in space  

NASA Technical Reports Server (NTRS)

Thermal control of future large space facilities, such as the space station, will require the transfer of anhydrous ammonia across rotating joints with near zero leakage. Anhydrous ammonia is the primary heat transfer fluid aboard the station, providing critical thermal management of habitat and payload systems. The solar radiator joints, as well as the various payload pointing systems, are obvious examples of the need for a reliable fluid transfer device. Low weight, tight temperature control, low parasitic drag torque, long life, and high reliability, in addition to near zero leakage, are important characteristics necessary for the successful operation of such a device. In late 1986, Lockheed initiated a project to develop a Rotary Transfer Coupling (RTC) directed toward space station requirements. Fabrication and assembly of this device is now complete and testing is scheduled. The design and development of the face seal-type rotary fluid coupling that utilizes a unique cover gas concept (an inert gas such as nitrogen) to provide full containment of the ammonia was addressed.

Warner, Mark H.

1988-01-01

468

Bacterial Ammonia Causes Significant Plant Growth Inhibition  

PubMed Central

Many and complex plant-bacteria inter-relationships are found in the rhizosphere, since plants release a variety of photosynthetic exudates from their roots and rhizobacteria produce multifaceted specialized compounds including rich mixtures of volatiles, e.g., the bouquet of Serratia odorifera 4Rx13 is composed of up to 100 volatile organic and inorganic compounds. Here we show that when growing on peptone-rich nutrient medium S. odorifera 4Rx13 and six other rhizobacteria emit high levels of ammonia, which during co-cultivation in compartmented Petri dishes caused alkalization of the neighboring plant medium and subsequently reduced the growth of A. thaliana. It is argued that in nature high-protein resource degradations (carcasses, whey, manure and compost) are also accompanied by bacterial ammonia emission which alters the pH of the rhizosphere and thereby influences organismal diversity and plant-microbe interactions. Consequently, bacterial ammonia emission may be more relevant for plant colonization and growth development than previously thought. PMID:23691060

Weise, Teresa; Kai, Marco; Piechulla, Birgit

2013-01-01

469

Interacting damage models mapped onto ising and percolation models  

SciTech Connect

The authors introduce a class of damage models on regular lattices with isotropic interactions between the broken cells of the lattice. Quasistatic fiber bundles are an example. The interactions are assumed to be weak, in the sense that the stress perturbation from a broken cell is much smaller than the mean stress in the system. The system starts intact with a surface-energy threshold required to break any cell sampled from an uncorrelated quenched-disorder distribution. The evolution of this heterogeneous system is ruled by Griffith's principle which states that a cell breaks when the release in potential (elastic) energy in the system exceeds the surface-energy barrier necessary to break the cell. By direct integration over all possible realizations of the quenched disorder, they obtain the probability distribution of each damage configuration at any level of the imposed external deformation. They demonstrate an isomorphism between the distributions so obtained and standard generalized Ising models, in which the coupling constants and effective temperature in the Ising model are functions of the nature of the quenched-disorder distribution and the extent of accumulated damage. In particular, they show that damage models with global load sharing are isomorphic to standard percolation theory, that damage models with local load sharing rule are isomorphic to the standard ising model, and draw consequences thereof for the universality class and behavior of the autocorrelation length of the breakdown transitions corresponding to these models. they also treat damage models having more general power-law interactions, and classify the breakdown process as a function of the power-law interaction exponent. Last, they also show that the probability distribution over configurations is a maximum of Shannon's entropy under some specific constraints related to the energetic balance of the fracture process, which firmly relates this type of quenched-disorder based damage model to standard statistical mechanics.

Toussaint, Renaud; Pride, Steven R.

2004-03-23

470

Bootstrap Percolation in Power-Law Random Graphs  

NASA Astrophysics Data System (ADS)

A bootstrap percolation process on a graph is an "infection" process which evolves in rounds. Initially, there is a subset of infected nodes and in each subsequent round each uninfected node which has at least infected neighbours becomes infected and remains so forever. The parameter is fixed. Such processes have been used as models for the spread of ideas or trends within a network of individuals. We analyse this process in the case where the underlying graph is an inhomogeneous random graph, which exhibits a power-law degree distribution, and initially there are randomly infected nodes. The main focus of this paper is the number of vertices that will have been infected by the end of the process. The main result of this work is that if the degree sequence of the random graph follows a power law with exponent , where , then a sublinear number of initially infected vertices is enough to spread the infection over a linear fraction of the nodes of the random graph, with high probability. More specifically, we determine explicitly a critical function such that with the following property. Assuming that is the number of vertices of the underlying random graph, if , then the process does not evolve at all, with high probability as grows, whereas if , then there is a constant such that, with high probability, the final set of infected vertices has size at least . This behaviour is in sharp contrast with the case where the underlying graph is a random graph with . It follows from an observation of Balogh and Bollobás that in this case if the number of initially infected vertices is sublinear, then there is lack of evolution of the process. It turns out that when the maximum degree is , then depends also on . But when the maximum degree is , then.

Amini, Hamed; Fountoulakis, Nikolaos

2014-04-01

471

National Center for Electronics Recycling  

NSDL National Science Digital Library

Used cellphones and laptops can't go in the recycling with the empty soda cans and cereal boxes. So where do they go to be recycled once consumers find new ones? The National Center for Electronics Recycling (NCER) is working on that very problem. Visitors can click on the "Ecycling Basics" tab on the left side of the page to be taken to links to three websites that allow you to search by zip code or an interactive map of the U.S. In the "Resources" tab on the left side of the page, there are many links to resources that include Advocacy Group Reports, Electronics Disposal Studies, Environmentally Sound Management Guidelines, and International documents. Visitors interested in keeping up with the news from NCER, can sign up for their newsletter in the Google groups box, which is located below the menu on the left side of the page.

472

The recyclability of lead alloys  

SciTech Connect

In 1996, the production of battery lead and alloys from the recycle industry was 3 times the Primary lead production in the United States. The Buick Resource Recovery Center of the Doe Run Lead Company at a capacity of 90,000 tons per year is one of 25 plants recycling lead metal in the United States. This plant was commissioned in 1991 and has been running with a 0.30 Lost Time Accident rate per 200,000 hours of work. The paper delineates and ranks the cost of treating various impurities found in lead.

Worcester, A.W.; Sankovitch, M.J. [Doe Run Co., Herculaneum, MO (United States)

1997-12-01

473

Recycler short kicker beam impedance  

SciTech Connect

Measured longitudinal and calculated transverse beam impedance is presented for the short kicker magnets being installed in the Fermilab Recycler. Fermi drawing number ME-457159. The longitudinal impedance was measured with a stretched wire and the Panofsky equation was used to estimate the transverse impedance. The impedance of 3319 meters (the Recycler circumference) of stainless vacuum pipe is provided for comparison. Although measurements where done to 3GHz, impedance was negligible above 30MHz. The beam power lost to the kicker impedance is shown for a range of bunch lengths. The measurements are for one kicker assuming a rotation frequency of 90KHz. Seven of these kickers are being installed.

Crisp, Jim; Fellenz, Brian; /Fermilab

2009-07-01

474

Process to recycle shredder residue  

DOEpatents

A system and process for recycling shredder residue, in which separating any polyurethane foam materials are first separated. Then separate a fines fraction of less than about 1/4 inch leaving a plastics-rich fraction. Thereafter, the plastics rich fraction is sequentially contacted with a series of solvents beginning with one or more of hexane or an alcohol to remove automotive fluids; acetone to remove ABS; one or more of EDC, THF or a ketone having a boiling point of not greater than about 125.degree. C. to remove PVC; and one or more of xylene or toluene to remove polypropylene and polyethylene. The solvents are recovered and recycled.

Jody, Bassam J. (Chicago, IL); Daniels, Edward J. (Oak Lawn, IL); Bonsignore, Patrick V. (Channahon, IL)

2001-01-01

475

A Guide to Running a Recycling Project. [Includes Recycling Handbook].  

ERIC Educational Resources Information Center

This guide, designed for both students and adults, is intended for individuals who feel they might be interested in establishing a recycling depot. The guide includes such pertinent information as deciding how to set up a depot, markets and transportation, preparation of materials, where to place the depot and when to operate it, publicity and…

Oregon Recycling Information and Organizing Network, Portland.

476

Automobile Recycling Policy: Findings and Recommendations  

E-print Network

This report focuses on recycling. As an objective neutral party, MIT has compiled a knowledge base that examines the many complex issues relating to re-cycling. Although this report was prepared at the request of the ...

Field, Frank

477

Food Service Recycling: Whose Responsibility Is It?  

ERIC Educational Resources Information Center

The food service department at a Pennsylvania school district recycles polystyrene "styrofoam" cups, plates, and food trays. In addition, the department recycles glass, aluminum, and paper. Offers advice on how to set up a school program. (MLF)

Settanni, Barbara

1990-01-01

478

Converting Garbage to Gold: Recycling Our Materials.  

ERIC Educational Resources Information Center

Recycling conserves energy, fights pollution and inflation, creates jobs, and improves the outlook for the future of materials. But converting a throwaway society to recycling will depend on finding good markets for waste paper and scrap metals. (RM)

Chandler, William U.

1984-01-01

479

Residential Refrigerator Recycling Ninth Year Retention Study  

E-print Network

Residential Refrigerator Recycling Ninth Year Retention Study Study ID Nos. 546B, 563 Prepared RECYCLING PROGRAMS Study ID Nos. 546B and 563 Prepared for Southern California Edison Rosemead, California

480

75 FR 71003 - America Recycles Day, 2010  

Federal Register 2010, 2011, 2012, 2013

...developments, including the recycling of electronic products...Currently, most discarded consumer electronics end up in...caused by electronic waste, American businesses...their use and eventual recycling, recovery, and disposal...leads as a responsible consumer, my...

2010-11-19

481

Compositional evaluation of asphalt binder recycling agents  

E-print Network

new asphalt binder. The high temperature Superpave TM Performance Grade (PG) specifications for recycled asphalt binders were found to be highly dependent on the aged asphalt. In addition, as the amount of saturates in the aromatic recycling agent...

Madrid, Richard Charles

2012-06-07

482

Preliminary data on the optical properties of solid ammonia and scattering parameters for ammonia cloud particles.  

NASA Technical Reports Server (NTRS)

The infrared absorption spectrum of solid ammonia is obtained from 2 to 125 microns as a composite of the published measurements. From this, the absorption coefficient and the complex refractive index are calculated as a function of frequency by integration of the Kramers-Kroenig dispersion relations. These data are used in a Mie theory analysis to obtain the basic parameters for scattering of long wavelength radiation by solid ammonia particles; this is believed to be an important process in radiative transfer within the atmospheres of the giant planets.

Taylor, F. W.

1973-01-01

483

Proceedings of the waste recycling workshop  

SciTech Connect

Recorded are seventeen talks from five sessions at the workshop. FERMCO`s recycling program, state of the art recycling technology, and an integrated demonstration of deactivation, decommissioning and decommissioning are presented in the plenary session. In the concrete session, decontamination and recycling are discussed. In the transite session, regulations are considered along with recycling and decontamination. In the metals session, radioactive scrap metals are emphasized. And in the regulatory considerations and liabilities session, DOE and EPA viewpoints are discussed. (GHH)

Bailey, R.E.; Thomas, A.F.; Ries, M.A. [eds.] [Ohio State Univ., Columbus, OH (United States)] [eds.; Ohio State Univ., Columbus, OH (United States)

1993-12-31

484

Waste Management and Recycling in Lab Batteries can be recycled in the VWR stockroom  

E-print Network

Waste Management and Recycling in Lab · Batteries can be recycled in the VWR stockroom · Electronic odors and collect the first rinse with its associated hazardous waste stream), remove or deface recycle it! · MIT recycled 2773 tons of waste in 2010 · Remember b onl hat o need!· Remember buy only what

Cohen, Robert E.

485

What Makes a Recycler?A Comparison of Recyclers and Nonrecyclers  

Microsoft Academic Search

Knowledge and motivational factors represent important but neglected topics in the study of recycling behavior. This article examines differences in knowledge, motives, and demographic characteristics of people who have the opportunity to recycle voluntarily. Information on these variables was obtained for 197 households in Illinois. The results indicated that recyclers in general were more aware of publicity about recycling and

Joanne Vining; Angela Ebreo

1990-01-01

486

Welcome new and returning residents! Help us make USC greener by recycling! Your Room Recycling Bin  

E-print Network

Recycling will take only a few minutes but will have a profound impact on the environment. MIXED PAPER White