49 CFR 173.137 - Class 8-Assignment of packing group.

Code of Federal Regulations, 2010 CFR

2010-10-01

... subchapter) as follows: (a) Packing Group I. Materials that cause full thickness destruction of intact skin... full thickness destruction of intact skin tissue within an observation period of up to 14 days starting... destruction of intact skin tissue within an observation period of up to 14 days starting after the exposure...

Effects of alternative label formats on choice of high- and low-sodium products in a New Zealand population sample.

PubMed

McLean, Rachael; Hoek, Janet; Hedderley, Duncan

2012-05-01

Dietary sodium reduction is a cost-effective public health intervention to reduce chronic disease. In response to calls for further research into front-of-pack labelling systems, we examined how alternative sodium nutrition label formats and nutrition claims influenced consumers' choice behaviour and whether consumers with or without a diagnosis of hypertension differed in their choice patterns. An anonymous online experiment in which participants viewed ten choice sets featuring three fictitious brands of baked beans with varied label formats and nutritional profiles (high and low sodium) and indicated which brand in each set they would purchase if shopping for this product. Participants were recruited from New Zealand's largest online nationwide research panel. Five hundred people with self-reported hypertension and 191 people without hypertension aged 18 to 79 years. The addition of a front-of-pack label increased both groups' ability to discriminate between products with high and low sodium, while the Traffic Light label enabled better identification of the high-sodium product. Both front-of-pack formats enhanced discrimination in the presence of a reduced salt claim, but the Traffic Light label also performed better than the Percentage Daily Intake label in moderating the effect of the claim for the high-sodium product. Front-of-pack labels, particularly those with simple visual cues, enhance consumers' ability to discriminate between high- and low-sodium products, even when those products feature nutrition claims.

Problem Based Learning: Use of the Portable Patient Problem Pack (P4).

ERIC Educational Resources Information Center

Scheiman, Mitchell; Whittaker, Steve

1991-01-01

The format and production of the portable patient problem pack, a patient simulation method designed for problem-based learning, are described. Clinical and didactic applications and development of materials specifically for optometric education are discussed and additional information for designing optometry-related materials is appended.…

Interaction between Proppant Packing, Reservoir Depletion, and Fluid Flow in Pore Space

NASA Astrophysics Data System (ADS)

Fan, M.; McClure, J. E.; Han, Y.; Chen, C.

2016-12-01

In the oil and gas industry, the performance of proppant pack in hydraulically created fractures has a significant influence on fracture conductivity. A better understanding of proppant transport and deposition pattern in a hydraulic fracture is vital for effective and economical production within oil and gas reservoirs. In this research, a numerical modeling approach, combining Particle Flow Code (PFC) and GPU-enhanced lattice Boltzmann simulator (GELBS), is adopted to advance the understanding of the interaction between proppant particle packing, depletion of reservoir formation, and transport of reservoir flow through the pore space. In this numerical work flow, PFC is used to simulate effective stress increase and proppant particle movement and rearrangement under increasing mechanical loading. The pore structure of the proppant pack evolves subsequently and the geometrical data are output for lattice Boltzmann (LB) simulation of proppant pack permeability. Three different proppant packs with fixed particle concentration and 12/18, 16/30, and 20/40 mesh sizes are generated. These proppant packs are compressed with specified loading stress and their subsequent geometries are used for fluid flow simulations. The simulation results are in good agreement with experimental observations, e.g., the conductivity of proppant packs decreases with increasing effective stress. Three proppant packs with the same average diameter were generated using different coefficients of variation (COVs) for the proppant diameter (namely cov5%, cov20%, and cov30%). By using the coupled PFC-LBM work flow, the proppant pack permeability as functions of effective stress and porosity is investigated. The results show that the proppant pack with a higher proppant diameter COV has lower permeability and porosity under the same effective stress, because smaller particles fill in the pore space between bigger particles. The relationship between porosity and permeability is also consistent with the Kozeny-Carman equation. In addition, relative permeability curves are obtained using multiphase LB simulation to study non-wetting phase trapping, which will benefit production forecasting and interpretation of formation damage. This research provides an advantageous alternative to expensive laboratory experiments.

Boundary conditions for diffusion in the pack-aluminizing of nickel.

NASA Technical Reports Server (NTRS)

Sivakumar, R.; Seigle, L. L.; Menon, N. B.

1973-01-01

The surface compositions of nickel specimens coated for various lengths of time in aluminizing packs at 2000 F were studied, in order to obtain information about the kinetics of the pack-cementation process in the formation of aluminide coatings. The results obtained indicate that the surface compositions of the coated nickel specimens are independent of time, at least for time between 0.5 and 20 hrs. Another important observation is that the specimens gained weight during the coating process.

Thermal Analysis of the Vulnerability of the Spacesuit Battery Design to Short-Circuit Conditions (Presentation)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, G. H.; Chaney, L.; Smith, K.

2010-04-22

NREL researchers created a mathematical model of a full 16p-5s spacesuit battery for NASA that captures electrical/thermal behavior during shorts to assess the vulnerability of the battery to pack-internal (cell-external) shorts. They found that relocating the short from battery pack-external (experimental validation) to pack-internal (modeling study) causes substantial additional heating of cells, which can lead to cell thermal runaway. All three layers of the bank-to-bank separator must fail for the pack-internal short scenario to occur. This finding emphasizes the imperative of battery pack assembly cleanliness. The design is tolerant to pack-internal shorts when stored at 0% state of charge.

The Portable Patient Problem Pack: A Problem-Based Learning Unit

ERIC Educational Resources Information Center

Barrows, Howard S.; Tamblyn, Robyn M.

1977-01-01

The Portable Patient Problem Pack (P4), a method of simulating a patient's problem in a card deck format, is designed to develop the student's problem-solving or diagnostic skills in a manner consistent with the skills of the practicing clinician. Its effectiveness at McMaster University is reported. (LBH)

Formation of polycrystalline MgB2 synthesized by powder in sealed tube method with different initial boron phase

NASA Astrophysics Data System (ADS)

Yudanto, Sigit Dwi; Imaduddin, Agung; Kurniawan, Budhy; Manaf, Azwar

2018-04-01

Magnesium diboride, MgB2 is a new high critical temperature superconductor that discovered in the beginning of the 21st century. The MgB2 has a simple crystal structure and a high critical temperature, which can be manufactured in several forms like thin films, tapes, wires including bulk in the large scale. For that reason, the MgB2 has good prospects for various applications in the field of electronic devices. In the current work, we have explored the synthesis of MgB2 polycrystalline using powder in a sealed tube method. Different initial boron phase for the synthesized of MgB2 polycrystalline were used. These were, in addition to magnesium powders, crystalline boron, amorphous boron and combination both of them were respectively fitted in the synthesis. The raw materials were mixed in a stoichiometric ratio of Mg: B=1:2, ground using agate mortar, packed into stainless steel SS304. The pack was then sintered at temperature of 800°C for 2 hours in air atmosphere. Phase formation of MgB2 polycrystalline in difference of initial boron phase was characterized using XRD and SEM. Referring to the diffraction pattern and microstructure observation, MgB2 polycrystalline was formed, and the formation was effective when using the crystalline Mg and fully amorphous B as the raw materials. The critical temperature of the specimen was evaluated by the cryogenic magnet. The transition temperature of the MgB2 specimen synthesized using crystalline magnesium and full amorphous boron is 42.678 K (ΔTc = 0.877 K).

Snowpack displacement measured by terrestrial radar interferometry as precursor for wet snow avalanches

NASA Astrophysics Data System (ADS)

Caduff, Rafael; Wiesmann, Andreas; Bühler, Yves

2016-04-01

Wet snow and full depth gliding avalanches commonly occur on slopes during springtime when air temperatures rise above 0°C for longer time. The increase in the liquid water content changes the mechanical properties of the snow pack. Until now, forecasts of wet snow avalanches are mainly done using weather data such as air and snow temperatures and incoming solar radiation. Even tough some wet snow avalanche events are indicated before the release by the formation of visible signs such as extension cracks or compressional bulges in the snow pack, a large number of wet snow avalanches are released without any previously visible signs. Continuous monitoring of critical slopes by terrestrial radar interferometry improves the scale of reception of differential movement into the range of millimetres per hour. Therefore, from a terrestrial and remote observation location, information on the mechanical state of the snow pack can be gathered on a slope wide scale. Recent campaigns in the Swiss Alps showed the potential of snow deformation measurements with a portable, interferometric real aperture radar operating at 17.2 GHz (1.76 cm wavelength). Common error sources for the radar interferometric measurement of snow pack displacements are decorrelation of the snow pack at different conditions, the influence of atmospheric disturbances on the interferometric phase and transition effects from cold/dry snow to warm/wet snow. Therefore, a critical assessment of those parameters has to be considered in order to reduce phase noise effects and retrieve accurate displacement measurements. The most recent campaign in spring 2015 took place in Davos Dorf/GR, Switzerland and its objective was to observe snow glide activity on the Dorfberg slope. A validation campaign using total station measurements showed good agreement to the radar interferometric line of sight displacement measurements in the range of 0.5 mm/h. The refinement of the method led to the detection of numerous gliding patches distributed over the entire slope. Typically, patches showing (full depth) snow gliding reach extensions from 5x10 metres up to 40x60 metres. Using a sampling interval of 1-3 minutes, the temporal displacement of such snow glide-hot spots can be tracked and thus revealing the individual signature of deformation. Nearly linear behaviour over several days, peaking in a final acceleration releasing an avalanche was observed as well characteristic acceleration and deceleration cycles during day and night could be captured. These cycles sometimes trigger an avalanche and sometimes reach a full stop of the differential snow glide movement. Findings of the different campaigns will be presented. We put them in the context for possible future campaigns that could be used to solve scientific questions regarding the mechanical properties of the snow pack. We evaluate the possibilities for the use of terrestrial radar interferometry for hazard management and avalanche forecast.

Calculating the Maximum Density of the Surface Packing of Ions in Ionic Liquids

NASA Astrophysics Data System (ADS)

Kislenko, S. A.; Moroz, Yu. O.; Karu, K.; Ivaništšev, V. B.; Fedorov, M. V.

2018-05-01

The maximum density of monolayer packing on a graphene surface is calculated by means of molecular dynamics (MD) for ions of characteristic size and symmetry: 1-butyl-3-methylimidazolium [BMIM]+, tetrabutylammonium [TBA]+, tetrafluoroborate [BF4]-, dicyanamide [DCA]-, and bis(trifluoromethane) sulfonimide [TFSI]-. The characteristic orientations of ions in a closely packed monolayer are found. It is shown that the formation of a closely packed monolayer is possible for [DCA]- and [BF4]- anions only at surface charges that exceed the limit of the electrochemical stability of the corresponding ionic liquids. For the [TBA]+ cation, a monolayer structure can be observed at the charge of nearly 30 μC/cm2 attainable in electrochemical experiment.

Presence of Counterfeit Marlboro Gold Packs in Licensed Retail Stores in New York City: Evidence From Test Purchases.

PubMed

Kurti, Marin; He, Yi; Silver, Diana; Giorgio, Margaret; von Lampe, Klaus; Macinko, James; Ye, Hua; Tan, Fidelis; Mei, Victoria

2018-05-26

There are no independent studies measuring the availability of premium brand counterfeit cigarettes in New York City from licensed retailers. We forensically analyzed the cigarette packaging of Marlboro Gold (n = 1021) purchased from licensed tobacco retailers in New York City, using ultraviolet irradiation and light microscopy to determine whether they were counterfeit. We find that while only 0.5% (n = 5) of our sample exhibits at least one characteristic synonymous with counterfeit packaging, none of our packs can be conclusively classified as counterfeit. We do not find any counterfeit Marlboro Gold packs purchased at full price from licensed cigarette retailers throughout New York City. Future research using test purchases should include other venues (eg, street and online) and specifically ask for discounts to ascertain the overall presence of counterfeit cigarettes. This is the first study to independently measure the availability of counterfeit cigarette packs purchased at full price from licensed retailers in New York City. We find that none of the Marlboro Gold packs purchased from licensed cigarette retailers are counterfeit.

An Amino Acid Code for β-sheet Packing Structure

PubMed Central

Joo, Hyun; Tsai, Jerry

2014-01-01

To understand the relationship between protein sequence and structure, this work extends the knob-socket model in an investigation of β-sheet packing. Over a comprehensive set of β-sheet folds, the contacts between residues were used to identify packing cliques: sets of residues that all contact each other. These packing cliques were then classified based on size and contact order. From this analysis, the 2 types of 4 residue packing cliques necessary to describe β-sheet packing were characterized. Both occur between 2 adjacent hydrogen bonded β-strands. First, defining the secondary structure packing within β-sheets, the combined socket or XY:HG pocket consists of 4 residues i,i+2 on one strand and j,j+2 on the other. Second, characterizing the tertiary packing between β-sheets, the knob-socket XY:H+B consists of a 3 residue XY:H socket (i,i+2 on one strand and j on the other) packed against a knob B residue (residue k distant in sequence). Depending on the packing depth of the knob B residue, 2 types of knob-sockets are found: side-chain and main-chain sockets. The amino acid composition of the pockets and knob-sockets reveal the sequence specificity of β-sheet packing. For β-sheet formation, the XY:HG pocket clearly shows sequence specificity of amino acids. For tertiary packing, the XY:H+B side-chain and main-chain sockets exhibit distinct amino acid preferences at each position. These relationships define an amino acid code for β-sheet structure and provide an intuitive topological mapping of β-sheet packing. PMID:24668690

Can front-of-pack labelling schemes guide healthier food choices? Australian shoppers' responses to seven labelling formats.

PubMed

Watson, Wendy L; Kelly, Bridget; Hector, Debra; Hughes, Clare; King, Lesley; Crawford, Jennifer; Sergeant, John; Chapman, Kathy

2014-01-01

There is evidence that easily accessible, comprehensible and consistent nutrient information on the front of packaged foods could assist shoppers to make healthier food choices. This study used an online questionnaire of 4357 grocery shoppers to examine Australian shoppers' ability to use a range of front-of-pack labels to identify healthier food products. Seven different front-of-pack labelling schemes comprising variants of the Traffic Light labelling scheme and the Percentage Daily Intake scheme, and a star rating scheme, were applied to nine pairs of commonly purchased food products. Participants could also access a nutrition information panel for each product. Participants were able to identify the healthier product in each comparison over 80% of the time using any of the five schemes that provided information on multiple nutrients. No individual scheme performed significantly better in terms of shoppers' ability to determine the healthier product, shopper reliance on the 'back-of-pack' nutrition information panel, and speed of use. The scheme that provided information about energy only and a scheme with limited numerical information of nutrient type or content performed poorly, as did the nutrition information panel alone (control). Further consumer testing is necessary to determine the optimal format and content of an interpretive front-of-pack nutrition labelling scheme. Copyright © 2013 Elsevier Ltd. All rights reserved.

Consumer support for healthy food and drink vending machines in public places.

PubMed

Carrad, Amy M; Louie, Jimmy Chun-Yu; Milosavljevic, Marianna; Kelly, Bridget; Flood, Victoria M

2015-08-01

To investigate the feasibility of introducing vending machines for healthier food into public places, and to examine the effectiveness of two front-of-pack labelling systems in the vending machine context. A survey was conducted with 120 students from a university and 120 employees, patients and visitors of a hospital in regional NSW, Australia. Questions explored vending machine use, attitudes towards healthier snack products and price, and the performance of front-of-pack labelling formats for vending machine products. Most participants viewed the current range of snacks and drinks as "too unhealthy" (snacks 87.5%; drinks 56.7%). Nuts and muesli bars were the most liked healthier vending machine snack. Higher proportions of participants were able to identify the healthier snack in three of the five product comparisons when products were accompanied with any type of front-of-pack label (all p<0.01); however, participants were less likely to be able to identify the healthier product in the drinks comparison when a front-of-pack guide was present. Respondents were interested in a range of healthier snacks for vending machines. Front-of-pack label formats on vending machines may assist consumers to identify healthier products. Public settings, such as universities and hospitals, should support consumers to make healthy dietary choices by improving food environments. © 2015 Public Health Association of Australia.

Topical thermal therapy with hot packs suppresses physical inactivity-induced mechanical hyperalgesia and up-regulation of NGF.

PubMed

Nakagawa, Tatsuki; Hiraga, Shin-Ichiro; Mizumura, Kazue; Hori, Kiyomi; Ozaki, Noriyuki; Koeda, Tomoko

2017-10-12

We focused on the analgesic effect of hot packs for mechanical hyperalgesia in physically inactive rats. Male Wistar rats were randomly divided into four groups: control, physical inactivity (PI), PI + sham treatment (PI + sham), and PI + hot pack treatment (PI + hot pack) groups. Physical inactivity rats wore casts on both hind limbs in full plantar flexed position for 4 weeks. Hot pack treatment was performed for 20 min a day, 5 days a week. Although mechanical hyperalgesia and the up-regulation of NGF in the plantar skin and gastrocnemius muscle were observed in the PI and the PI + sham groups, these changes were significantly suppressed in the PI + hot pack group. The present results clearly demonstrated that hot pack treatment was effective in reducing physical inactivity-induced mechanical hyperalgesia and up-regulation of NGF in plantar skin and gastrocnemius muscle.

Coverage Dependent Assembly of Anthraquinone on Au(111)

NASA Astrophysics Data System (ADS)

Conrad, Brad; Deloach, Andrew; Einstein, Theodore; Dougherty, Daniel

A study of adsorbate-adsorbate and surface state mediated interactions of anthraquinone (AnQ) on Au(111) is presented. We utilize scanning tunneling microscopy (STM) to characterize the coverage dependence of AnQ structure formation. Ordered structures are observed up to a single monolayer (ML) and are found to be strongly dependent on molecular surface density. While the complete ML forms a well-ordered close-packed layer, for a narrow range of sub-ML coverages irregular close-packed islands are observed to coexist with a disordered pore network linking neighboring islands. This network displays a characteristic pore size and at lower coverages, the soliton walls of the herringbone reconstruction are shown to promote formation of distinct pore nanostructures. We will discuss these nanostructure formations in the context of surface mediated and more direct adsorbate interactions.

Rail vehicle dynamic response to a nonlinear physical 'in-service' model of its secondary suspension hydraulic dampers

NASA Astrophysics Data System (ADS)

Wang, W. L.; Zhou, Z. R.; Yu, D. S.; Qin, Q. H.; Iwnicki, S.

2017-10-01

A full nonlinear physical 'in-service' model was built for a rail vehicle secondary suspension hydraulic damper with shim-pack-type valves. In the modelling process, a shim pack deflection theory with an equivalent-pressure correction factor was proposed, and a Finite Element Analysis (FEA) approach was applied. Bench test results validated the damper model over its full velocity range and thus also proved that the proposed shim pack deflection theory and the FEA-based parameter identification approach are effective. The validated full damper model was subsequently incorporated into a detailed vehicle dynamics simulation to study how its key in-service parameter variations influence the secondary-suspension-related vehicle system dynamics. The obtained nonlinear physical in-service damper model and the vehicle dynamic response characteristics in this study could be used in the product design optimization and nonlinear optimal specifications of high-speed rail hydraulic dampers.

Chiral Structures of Thermoresponsive Soft Spheres in Hollow Cylinders

NASA Astrophysics Data System (ADS)

Lohr, Matthew A.; Alsayed, Ahmed; Zhang, Zexin; Yodh, Arjun G.

2009-03-01

We experimentally observe the formation of closely packed crystalline structures in hollow cylinders. The structures have varying degrees of chiral order. The systems are created from aqueous suspensions of thermoresponsive N-isopropylacrylamide (NIPA) microgel particles packed in micron-diameter glass capillaries. We categorize these structures according to classifications used by Erickson for tubular packings of hard spheres [1]. By varying the temperature-tunable diameter of these particles, the system's volume fraction is changed, permitting observations of the resilience of these structures and their melting transitions. Melting of these thermal crystalline structures is observed. [1] R. O. Erickson, Science 181 (1973) 705-716.

How does increasingly plainer cigarette packaging influence adult smokers’ perceptions about brand image? An experimental study

PubMed Central

Wakefield, M A; Germain, D; Durkin, S J

2008-01-01

Background: Cigarette packaging is a key marketing strategy for promoting brand image. Plain packaging has been proposed to limit brand image, but tobacco companies would resist removal of branding design elements. Method: A 3 (brand types) × 4 (degree of plain packaging) between-subject experimental design was used, using an internet online method, to expose 813 adult Australian smokers to one randomly selected cigarette pack, after which respondents completed ratings of the pack. Results: Compared with current cigarette packs with full branding, cigarette packs that displayed progressively fewer branding design elements were perceived increasingly unfavourably in terms of smokers’ appraisals of the packs, the smokers who might smoke such packs, and the inferred experience of smoking a cigarette from these packs. For example, cardboard brown packs with the number of enclosed cigarettes displayed on the front of the pack and featuring only the brand name in small standard font at the bottom of the pack face were rated as significantly less attractive and popular than original branded packs. Smokers of these plain packs were rated as significantly less trendy/stylish, less sociable/outgoing and less mature than smokers of the original pack. Compared with original packs, smokers inferred that cigarettes from these plain packs would be less rich in tobacco, less satisfying and of lower quality tobacco. Conclusion: Plain packaging policies that remove most brand design elements are likely to be most successful in removing cigarette brand image associations. PMID:18827035

How does increasingly plainer cigarette packaging influence adult smokers' perceptions about brand image? An experimental study.

PubMed

Wakefield, M A; Germain, D; Durkin, S J

2008-12-01

Cigarette packaging is a key marketing strategy for promoting brand image. Plain packaging has been proposed to limit brand image, but tobacco companies would resist removal of branding design elements. A 3 (brand types) x 4 (degree of plain packaging) between-subject experimental design was used, using an internet online method, to expose 813 adult Australian smokers to one randomly selected cigarette pack, after which respondents completed ratings of the pack. Compared with current cigarette packs with full branding, cigarette packs that displayed progressively fewer branding design elements were perceived increasingly unfavourably in terms of smokers' appraisals of the packs, the smokers who might smoke such packs, and the inferred experience of smoking a cigarette from these packs. For example, cardboard brown packs with the number of enclosed cigarettes displayed on the front of the pack and featuring only the brand name in small standard font at the bottom of the pack face were rated as significantly less attractive and popular than original branded packs. Smokers of these plain packs were rated as significantly less trendy/stylish, less sociable/outgoing and less mature than smokers of the original pack. Compared with original packs, smokers inferred that cigarettes from these plain packs would be less rich in tobacco, less satisfying and of lower quality tobacco. Plain packaging policies that remove most brand design elements are likely to be most successful in removing cigarette brand image associations.

Effect of chain stiffness on the competition between crystallization and glass-formation in model unentangled polymers

NASA Astrophysics Data System (ADS)

Nguyen, Hong T.; Smith, Tyler B.; Hoy, Robert S.; Karayiannis, Nikos Ch.

2015-10-01

We map out the solid-state morphologies formed by model soft-pearl-necklace polymers as a function of chain stiffness, spanning the range from fully flexible to rodlike chains. The ratio of Kuhn length to bead diameter (lK/r0) increases monotonically with increasing bending stiffness kb and yields a one-parameter model that relates chain shape to bulk morphology. In the flexible limit, monomers occupy the sites of close-packed crystallites while chains retain random-walk-like order. In the rodlike limit, nematic chain ordering typical of lamellar precursors coexists with close-packing. At intermediate values of bending stiffness, the competition between random-walk-like and nematic chain ordering produces glass-formation; the range of kb over which this occurs increases with the thermal cooling rate | T ˙ | implemented in our molecular dynamics simulations. Finally, values of kb between the glass-forming and rodlike ranges produce complex ordered phases such as close-packed spirals. Our results should provide a useful initial step in a coarse-grained modeling approach to systematically determining the effect of chain stiffness on the crystallization-vs-glass-formation competition in both synthetic and colloidal polymers.

Random close packing of polydisperse jammed emulsions

NASA Astrophysics Data System (ADS)

Brujic, Jasna

2010-03-01

Packing problems are everywhere, ranging from oil extraction through porous rocks to grain storage in silos and the compaction of pharmaceutical powders into tablets. At a given density, particulate systems pack into a mechanically stable and amorphous jammed state. Theoretical frameworks have proposed a connection between this jammed state and the glass transition, a thermodynamics of jamming, as well as geometric modeling of random packings. Nevertheless, a simple underlying mechanism for the random assembly of athermal particles, analogous to crystalline ordering, remains unknown. Here we use 3D measurements of polydisperse packings of emulsion droplets to build a simple statistical model in which the complexity of the global packing is distilled into a local stochastic process. From the perspective of a single particle the packing problem is reduced to the random formation of nearest neighbors, followed by a choice of contacts among them. The two key parameters in the model, the available space around a particle and the ratio of contacts to neighbors, are directly obtained from experiments. Remarkably, we demonstrate that this ``granocentric'' view captures the properties of the polydisperse emulsion packing, ranging from the microscopic distributions of nearest neighbors and contacts to local density fluctuations and all the way to the global packing density. Further applications to monodisperse and bidisperse systems quantitatively agree with previously measured trends in global density. This model therefore reveals a general principle of organization for random packing and lays the foundations for a theory of jammed matter.

Comparison of packing material in an animal model of middle ear trauma.

PubMed

Perez, Enrique; Hachem, Ralph Abi; Carlton, Daniel; Bueno, Isabel; Vernon, Stephen; Van De Water, Thomas R; Angeli, Simon I

2016-01-01

To compare the performance of absorbable gelatin sponge (AGS) with polyurethane foam (PUF) as middle ear packing material after mucosal trauma. Using a randomized, controlled and blinded study design fifteen guinea pigs underwent middle ear surgery with mucosal trauma performed on both ears. One ear was packed with either PUF or AGS while the contralateral ear remained untreated and used as non-packed paired controls. Auditory brainstem response (ABR) thresholds were measured pre-operatively and repeated at 1, 2, and 6weeks postoperatively. Histological analysis of middle ear mucosa was done in each group to evaluate the inflammatory reaction and wound healing. Another eighteen animals underwent middle ear wounding and packing in one ear while the contralateral ear was left undisturbed as control. Twelve guinea pigs were euthanized at 2weeks postoperatively, and six were euthanized at 3days post-operatively. Mucosal samples were collected for analysis of TGF-β1 levels by enzyme-linked immunosorbent assay. ABR recordings demonstrate that threshold level changes from baseline were minor in PUF packed and control ears. Threshold levels were higher in the AGS packed ears compared with both control and PUF packed ears for low frequency stimuli. Histological analysis showed persistence of packing material at 6weeks postoperatively, inflammation, granulation tissue formation, foreign body reaction and neo-osteogenesis in both AGS and PUF groups. TGF-β1 protein levels did not differ between groups. PUF and AGS packing cause inflammation and neo-osteogenesis in the middle ear following wounding of the mucosa and packing. Copyright © 2016 Elsevier Inc. All rights reserved.

Spontaneous Planar Chiral Symmetry Breaking in Cells

NASA Astrophysics Data System (ADS)

Hadidjojo, Jeremy; Lubensky, David

Recent progress in animal development has highlighted the central role played by planar cell polarity (PCP) in epithelial tissue morphogenesis. Through PCP, cells have the ability to collectively polarize in the plane of the epithelium by localizing morphogenetic proteins along a certain axis. This allows direction-dependent modulation of tissue mechanical properties that can translate into the formation of complex, non-rotationally invariant shapes. Recent experimental observations[1] show that cells, in addition to being planar-polarized, can also spontaneously develop planar chirality, perhaps in the effort of making yet more complex shapes that are reflection non-invariant. In this talk we will present our work in characterizing general mechanisms that can lead to spontaneous chiral symmetry breaking in cells. We decompose interfacial concentration of polarity proteins in a hexagonal cell packing into irreducible representations. We find that in the case of polar concentration distributions, a chiral state can only be reached from a secondary instability after the cells are polarized. However in the case of nematic distributions, we show that a finite-amplitude (subcritical, or ``first-order'') nematic transition can send the system from disorder directly to a chiral state. In addition, we find that perturbing the system by stretching the hexagonal packing enables direct (supercritical, or ``second-order'') chiral transition in the nematic case. Finally, we do a Landau expansion to study competition between stretch-induced chirality and the tendency towards a non-chiral state in packings that have retained the full 6-fold symmetry.

An amyloid-forming peptide from the yeast prion Sup35 reveals a dehydrated β-sheet structure for amyloid

PubMed Central

Balbirnie, Melinda; Grothe, Robert; Eisenberg, David S.

2001-01-01

X-ray diffraction and other biophysical tools reveal features of the atomic structure of an amyloid-like crystal. Sup35, a prion-like protein in yeast, forms fibrillar amyloid assemblies intrinsic to its prion function. We have identified a polar peptide from the N-terminal prion-determining domain of Sup35 that exhibits the amyloid properties of full-length Sup35, including cooperative kinetics of aggregation, fibril formation, binding of the dye Congo red, and the characteristic cross-β x-ray diffraction pattern. Microcrystals of this peptide also share the principal properties of the fibrillar amyloid, including a highly stable, β-sheet-rich structure and the binding of Congo red. The x-ray powder pattern of the microcrystals, extending to 0.9-Å resolution, yields the unit cell dimensions of the well-ordered structure. These dimensions restrict possible atomic models of this amyloid-like structure and demonstrate that it forms packed, parallel-stranded β-sheets. The unusually high density of the crystals shows that the packed β-sheets are dehydrated, despite the polar character of the side chains. These results suggest that amyloid is a highly intermolecularly bonded, dehydrated array of densely packed β-sheets. This dry β-sheet could form as Sup35 partially unfolds to expose the peptide, permitting it to hydrogen-bond to the same peptide of other Sup35 molecules. The implication is that amyloid-forming units may be short segments of proteins, exposed for interactions by partial unfolding. PMID:11226247

Preliminary investigations on a new method of retaining the colour of shucked cockles ( Anadara Granosa), and the extension of shelflife by gamma irradiation and vacuum packing

NASA Astrophysics Data System (ADS)

Ng, Cher Siang; Low, Lai Kim; Chia, Lawrence H. L.

Live cockles were incubated in atmospheres containing different concentrations of carbon monoxide. Since CO combines more readily with myoglobin and haemoglobin than oxygen, the formation of in vivo deoxygenated haemoglobins and post mortem formation of methaemoglobin were retarded by the more stable carboxyhaemoglobin (HbCO). The bright red colour of the stable HbCO is retained during storage, giving the desired colour to the cockles. The colour of normal, chilled cockle meat deteriorated after 3 days ice storage while those treated with 50 and 100% CO retained the bright deep orange colour up to 10 days storage. Irradiation caused faster colour deterioration in both CO and non-CO treated samples. Vacuum packing influenced the colour of the cockles with irradiation and with CO treatments. In non-CO treated, irradiated samples, the effect of vacuum packing was not obvious. In CO treated, irradiated samples, vacuum packing retarded the deterioration of colour. Odour developments were influenced by irradiation, vacuum packing and storage temperature, and were not influenced by CO treatments. Irradiation suppressed the development of odour for the first 11 days storage (0°C) while vacuum packing depressed the odour by lowering its intensity instead. Odour development was slowed down by lowering the storage temperature. The odour of shucked cockles was rejected within one day at room temperature (26-28°C) while at 0°C the odour of the shucked cockles was still acceptable after 10 days. Suitable chemical indices for quality are K value and TVBN. Treatment with CO did not influence the K value development. Vacuum packing produced the highest K values after 19 days storage (0°C), while irradiated samples had higher K values than non-irradiated samples. The TVBN increased with storage and is an indicator of the odour development. The use of CO treatment extended the shelflife of the cockles based on appearance. A combination of CO treatment, vacuum packing, ice storage and irradiation extended the shelflife to beyond 18 days, based on odour, colour, and overall appearance.

Ultratight crystal packing of a 10 kDa protein

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trillo-Muyo, Sergio; Jasilionis, Andrius; Domagalski, Marcin J.

2013-03-01

The crystal structure of the C-terminal domain of a putative U32 peptidase from G. thermoleovorans is reported; it is one of the most tightly packed protein structures reported to date. While small organic molecules generally crystallize forming tightly packed lattices with little solvent content, proteins form air-sensitive high-solvent-content crystals. Here, the crystallization and full structure analysis of a novel recombinant 10 kDa protein corresponding to the C-terminal domain of a putative U32 peptidase are reported. The orthorhombic crystal contained only 24.5% solvent and is therefore among the most tightly packed protein lattices ever reported.

Process for vaporizing a liquid hydrocarbon fuel

DOEpatents

Szydlowski, Donald F.; Kuzminskas, Vaidotas; Bittner, Joseph E.

1981-01-01

The object of the invention is to provide a process for vaporizing liquid hydrocarbon fuels efficiently and without the formation of carbon residue on the apparatus used. The process includes simultaneously passing the liquid fuel and an inert hot gas downwardly through a plurality of vertically spaed apart regions of high surface area packing material. The liquid thinly coats the packing surface, and the sensible heat of the hot gas vaporizes this coating of liquid. Unvaporized liquid passing through one region of packing is uniformly redistributed over the top surface of the next region until all fuel has been vaporized using only the sensible heat of the hot gas stream.

Aqueous Lyotropic Liquid Crystalline Frank-Kasper Mesophases

NASA Astrophysics Data System (ADS)

Mahanthappa, Mahesh; Kim, Sung A.; Jeong, Kyeong-Jun; Yethiraj, Arun

Amphiphilic molecules undergo water concentration-dependent self-assembly to form lyotropic liquid crystal (LLC) mesophases. LLC morphology selection is directed by cooperative optimization of preferred molecular packing arrangements, which stem from a subtle balance of local, non-covalent interactions. We recently discovered a class of amphiphiles that form a progression of discontinuous micellar LLCs, including two tetrahedrally-closest packed Frank-Kasper phases that exhibit exceptional long range order. This discovery complements recent reports of their formation in thermotropic liquid crystals, neat diblock and tetrablock polymers, and in lyotropic mesophases of block polymers in ionic liquids. Using a combination of MD simulations and experiments, we provide new insights into the mechanisms of formation for these low symmetry micelle phases.

Reovirus FAST Proteins Drive Pore Formation and Syncytiogenesis Using a Novel Helix-Loop-Helix Fusion-Inducing Lipid Packing Sensor

PubMed Central

Sarker, Muzaddid; de Antueno, Roberto; Langelaan, David N.; Parmar, Hiren B.; Shin, Kyungsoo; Rainey, Jan K.; Duncan, Roy

2015-01-01

Pore formation is the most energy-demanding step during virus-induced membrane fusion, where high curvature of the fusion pore rim increases the spacing between lipid headgroups, exposing the hydrophobic interior of the membrane to water. How protein fusogens breach this thermodynamic barrier to pore formation is unclear. We identified a novel fusion-inducing lipid packing sensor (FLiPS) in the cytosolic endodomain of the baboon reovirus p15 fusion-associated small transmembrane (FAST) protein that is essential for pore formation during cell-cell fusion and syncytiogenesis. NMR spectroscopy and mutational studies indicate the dependence of this FLiPS on a hydrophobic helix-loop-helix structure. Biochemical and biophysical assays reveal the p15 FLiPS preferentially partitions into membranes with high positive curvature, and this partitioning is impeded by bis-ANS, a small molecule that inserts into hydrophobic defects in membranes. Most notably, the p15 FLiPS can be functionally replaced by heterologous amphipathic lipid packing sensors (ALPS) but not by other membrane-interactive amphipathic helices. Furthermore, a previously unrecognized amphipathic helix in the cytosolic domain of the reptilian reovirus p14 FAST protein can functionally replace the p15 FLiPS, and is itself replaceable by a heterologous ALPS motif. Anchored near the cytoplasmic leaflet by the FAST protein transmembrane domain, the FLiPS is perfectly positioned to insert into hydrophobic defects that begin to appear in the highly curved rim of nascent fusion pores, thereby lowering the energy barrier to stable pore formation. PMID:26061049

Energy Storage Thermal Safety | Transportation Research | NREL

Science.gov Websites

battery exterior to activate the short, as do most of the other evaluation methodologies, but instead cells, modules, sub-packs, and some full-size battery packs, as well as across energy systems. Learn batteries and across energy storage systems, providing designers and manufacturers with the information

Effect of different brewing times on soluble oxalate content of loose-packed black teas and tea bags.

PubMed

Mahdavi, Reza; Lotfi Yagin, Neda; Liebman, Michael; Nikniaz, Zeinab

2013-02-01

Because of the postulated role of increased dietary oxalate intake in calcium oxalate stone formation, the effect of different brewing times on soluble oxalate contents of loose-packed black tea and tea bags was studied. The oxalate content of 25 different samples of loose-packed black teas after brewing at 5, 10, 15, 30, and 60 min and of ten brands of tea bags after infusion for 1, 2, 3, 4, and 5 min was measured by enzymatic assay. The oxalate concentration resulting from different brewing times ranged from 4.3 to 6.2 mg/240 ml for loose-packed black teas and from 2.7 to 4.8 mg/240 ml for tea bags. There was a stepwise increase in oxalate concentration associated with increased brewing times.

Clinical outcome and patient satisfaction using biodegradable (NasoPore) and non-biodegradable packing, a double-blind, prospective, randomized study.

PubMed

Burduk, Pawel Krzysztof; Wierzchowska, Malgorzata; Grześkowiak, Blazej; Kaźmierczak, Wojciech; Wawrzyniak, Katarzyna

Nasal packing after endoscopic sinus surgery is used as a standard procedure. The optimum solution to minimize or eliminate all disadvantages of this procedure may be accomplished using biodegradable packs. The aim of this study was to compare patient satisfaction and clinical outcome associated with absorbable and non-absorbable packing after FESS. In total, 50 patients were included in a prospective, double-blind, randomized trial. One side was packed with polyurethane foam, while the opposite side was packed with gauze packing. On the 2nd, 10th, and 30th postoperative day, the patients were questioned with the aid of a visual analog scale. The standardized questionnaires for bleeding, nasal breathing, feeling of pressure, and headache were used. The presence of synechiae, infection, or granulation was noted and recorded with the video-endoscopy. A significant difference according to lower pressure was found in the NasoPore group compared to the controls on day ten after surgery. The NasoPore packing had lower scores with respect to postoperative nose blockage on the 2nd and 10th days. Mucosal healing was better for the NasoPore group, both at day ten and 30 compared with the control group. The overall patient comfort is higher when using NasoPore compared to non-resorbable traditional impregnated gauze packing. Intensive saline douches applied three to four times per day are mandatory after the operation to prevent synechiae formation and fluid resorption by the packing. Published by Elsevier Editora Ltda.

Optimization of heterogeneous Bin packing using adaptive genetic algorithm

NASA Astrophysics Data System (ADS)

Sridhar, R.; Chandrasekaran, M.; Sriramya, C.; Page, Tom

2017-03-01

This research is concentrates on a very interesting work, the bin packing using hybrid genetic approach. The optimal and feasible packing of goods for transportation and distribution to various locations by satisfying the practical constraints are the key points in this project work. As the number of boxes for packing can not be predicted in advance and the boxes may not be of same category always. It also involves many practical constraints that are why the optimal packing makes much importance to the industries. This work presents a combinational of heuristic Genetic Algorithm (HGA) for solving Three Dimensional (3D) Single container arbitrary sized rectangular prismatic bin packing optimization problem by considering most of the practical constraints facing in logistic industries. This goal was achieved in this research by optimizing the empty volume inside the container using genetic approach. Feasible packing pattern was achieved by satisfying various practical constraints like box orientation, stack priority, container stability, weight constraint, overlapping constraint, shipment placement constraint. 3D bin packing problem consists of ‘n’ number of boxes being to be packed in to a container of standard dimension in such a way to maximize the volume utilization and in-turn profit. Furthermore, Boxes to be packed may be of arbitrary sizes. The user input data are the number of bins, its size, shape, weight, and constraints if any along with standard container dimension. This user input were stored in the database and encoded to string (chromosomes) format which were normally acceptable by GA. GA operators were allowed to act over these encoded strings for finding the best solution.

Group size, individual role differentiation and effectiveness of cooperation in a homogeneous group of hunters

PubMed Central

Escobedo, R.; Muro, C.; Spector, L.; Coppinger, R. P.

2014-01-01

The emergence of cooperation in wolf-pack hunting is studied using a simple, homogeneous, particle-based computational model. Wolves and prey are modelled as particles that interact through attractive and repulsive forces. Realistic patterns of wolf aggregation readily emerge in numerical simulations, even though the model includes no explicit wolf–wolf attractive forces, showing that the form of cooperation needed for wolf-pack hunting can take place even among strangers. Simulations are used to obtain the stationary states and equilibria of the wolves and prey system and to characterize their stability. Different geometric configurations for different pack sizes arise. In small packs, the stable configuration is a regular polygon centred on the prey, while in large packs, individual behavioural differentiation occurs and induces the emergence of complex behavioural patterns between privileged positions. Stable configurations of large wolf-packs include travelling and rotating formations, periodic oscillatory behaviours and chaotic group behaviours. These findings suggest a possible mechanism by which larger pack sizes can trigger collective behaviours that lead to the reduction and loss of group hunting effectiveness, thus explaining the observed tendency of hunting success to peak at small pack sizes. They also explain how seemingly complex collective behaviours can emerge from simple rules, among agents that need not have significant cognitive skills or social organization. PMID:24694897

Seeding hydrate formation in water-saturated sand with dissolved-phase methane obtained from hydrate dissolution: A progress report

USGS Publications Warehouse

Waite, William F.; Osegovic, J.P.; Winters, William J.; Max, M.D.; Mason, David H.

2008-01-01

An isobaric flow loop added to the Gas Hydrate And Sediment Test Laboratory Instrument (GHASTLI) is being investigated as a means of rapidly forming methane hydrate in watersaturated sand from methane dissolved in water. Water circulates through a relatively warm source chamber, dissolving granular methane hydrate that was pre-made from seed ice, then enters a colder hydrate growth chamber where hydrate can precipitate in a water-saturated sand pack. Hydrate dissolution in the source chamber imparts a known methane concentration to the circulating water, and hydrate particles from the source chamber entrained in the circulating water can become nucleation sites to hasten the onset of hydrate formation in the growth chamber. Initial results suggest hydrate grows rapidly near the growth chamber inlet. Techniques for establishing homogeneous hydrate formation throughout the sand pack are being developed.

Synthesis of Energetic Polymers.

DTIC Science & Technology

1981-10-15

demonstrated by a single peak in the gc analysis (injector temperature 2500 C). The reaction will be repeated in a different solvent to avoid the formation of...glass column packed with 10% OV-101 on chrom Q, with n-decane as an internal standard. Rates of polymerization were calculated using the assumption...the Kelen-Tudos method. The disappearance of monomer was monitored by gas chromatography, using a glass column packed with 10% OV-101 on Chrom Q

Optimal packing for cascaded regenerative transmission based on phase sensitive amplifiers.

PubMed

Sorokina, Mariia; Sygletos, Stylianos; Ellis, Andrew D; Turitsyn, Sergei

2013-12-16

We investigate the transmission performance of advanced modulation formats in nonlinear regenerative channels based on cascaded phase sensitive amplifiers. We identify the impact of amplitude and phase noise dynamics along the transmission line and show that after a cascade of regenerators, densely packed single ring PSK constellations outperform multi-ring constellations. The results of this study will greatly simplify the design of future nonlinear regenerative channels for ultra-high capacity transmission.

Structure of marginally jammed polydisperse packings of frictionless spheres

NASA Astrophysics Data System (ADS)

Zhang, Chi; O'Donovan, Cathal B.; Corwin, Eric I.; Cardinaux, Frédéric; Mason, Thomas G.; Möbius, Matthias E.; Scheffold, Frank

2015-03-01

We model the packing structure of a marginally jammed bulk ensemble of polydisperse spheres. To this end we expand on the granocentric model [Clusel et al., Nature (London) 460, 611 (2009), 10.1038/nature08158], explicitly taking into account rattlers. This leads to a relationship between the characteristic parameters of the packing, such as the mean number of neighbors and the fraction of rattlers, and the radial distribution function g (r ) . We find excellent agreement between the model predictions for g (r ) and packing simulations, as well as experiments on jammed emulsion droplets. The observed quantitative agreement opens the path towards a full structural characterization of jammed particle systems for imaging and scattering experiments.

TI-59 helps predict IPRs for gravel-packed gas wells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capdevielle, W.C.

The inflow performance relationship (IPR) is an important tool for reservoir and production engineers. It helps optimize completion, tubing, gas lift, and storm choke design. It facilitates accurate rate predictions that can be used to evaluate field development decisions. The IPR is the first step of the systems analysis that translates reservoir rock and fluid parameters into predictable flow rates. Use of gravel packing for sand control complicates the calculation that predicts a well's IPR curve, particularly in gas wells where high velocities in the formation and through gravel-filled perforation tunnels can cause turbulent flow. The program presented in thismore » article calculates the pressure drop and the flowing bottomhole pressures at varying flow rates for gravel-packed gas wells. The program was written for a Texas Instruments TI-59 programmable calculator with a PC-100 printer. Program features include: Calculations for in-casing gravel packs, open-hole gravel packs, or ungravel packed wells. Program prompts for the required data variables. Easy change of data values to run new cases. Calculates pressures for an unlimited number of flow rates. Results show the total pressure drop and the relative magnitude of its components.« less

USE OF CARBON STABLE ISOTOPE TO INVESTIGATE CHLOROMETHANE FORMATION IN THE ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE

EPA Science Inventory

Carbon stable isotope trichloroethylene (¹³C TCE) was used to investigate the formation of chloromethane (CM) during the electrolytic dechlorination of trichloroethylene (TCE) at a granular-graphite packed cathode. A method was developed to use a conventional GC/MS to ...

Crystallization process

DOEpatents

Adler, Robert J.; Brown, William R.; Auyang, Lun; Liu, Yin-Chang; Cook, W. Jeffrey

1986-01-01

An improved crystallization process is disclosed for separating a crystallizable material and an excluded material which is at least partially excluded from the solid phase of the crystallizable material obtained upon freezing a liquid phase of the materials. The solid phase is more dense than the liquid phase, and it is separated therefrom by relative movement with the formation of a packed bed of solid phase. The packed bed is continuously formed adjacent its lower end and passed from the liquid phase into a countercurrent flow of backwash liquid. The packed bed extends through the level of the backwash liquid to provide a drained bed of solid phase adjacent its upper end which is melted by a condensing vapor.

Low-symmetry sphere packings of simple surfactant micelles induced by ionic sphericity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Sung A.; Jeong, Kyeong-Jun; Yethiraj, Arun

We report the discovery of an ionic small molecule surfactant that undergoes water-drive self- assembly into quasispherical micelles, which pack into the first lyotropic liquid crystalline Frank–Kasper σ phase. Small-angle X-ray scattering studies indicate that this unexpected, low-symmetry phase is characterized by a tetragonal unit cell, in which 30 sub-2 nm micelles of five discrete types are arranged into a tetrahedral close packing with exceptional translational order. Varying the relative amounts of surfactant and water in these lyotropic phases enables formation of a Frank–Kasper A15 sphere packing and a more common body-centered cubic structure. MD simulations reveal that the symmetrymore » breaking that drives the selection of the σ and A15 phases arises from a delicate interplay between the drive to maintain local spherical particle symmetry and the maximization of electrostatic cohesion between the soft micellar particles.« less

Low-symmetry sphere packings of simple surfactant micelles induced by ionic sphericity

DOE PAGES

Kim, Sung A.; Jeong, Kyeong-Jun; Yethiraj, Arun; ...

2017-04-03

We report the discovery of an ionic small molecule surfactant that undergoes water-drive self- assembly into quasispherical micelles, which pack into the first lyotropic liquid crystalline Frank–Kasper σ phase. Small-angle X-ray scattering studies indicate that this unexpected, low-symmetry phase is characterized by a tetragonal unit cell, in which 30 sub-2 nm micelles of five discrete types are arranged into a tetrahedral close packing with exceptional translational order. Varying the relative amounts of surfactant and water in these lyotropic phases enables formation of a Frank–Kasper A15 sphere packing and a more common body-centered cubic structure. MD simulations reveal that the symmetrymore » breaking that drives the selection of the σ and A15 phases arises from a delicate interplay between the drive to maintain local spherical particle symmetry and the maximization of electrostatic cohesion between the soft micellar particles.« less

Continuous-feed electrochemical cell with nonpacking particulate electrode

DOEpatents

Cooper, John F.

1995-01-01

An electrochemical cell providing full consumption of electrochemically active particles in a nonpacking, electrolyte-permeable bed has a tapered cell cavity bounded by two nonparallel surfaces separated by a distance that promotes bridging of particles across the cavity. The gap/particle size ratio is maintained as the particles are consumed, decrease in size, and travel from the point of entry to the narrower end of the cell. A cell of this configuration supports a bed of low packing density maintained in a dynamic steady state by alternate formation and collapse of particle bridges across the gap and associated voids over the entire active area of the cell. The cell design can be applied to refuelable zinc/air cells and zinc/ferrocyanide storage batteries.

Continuous-feed electrochemical cell with nonpacking particulate electrode

DOEpatents

Cooper, J.F.

1995-07-18

An electrochemical cell providing full consumption of electrochemically active particles in a nonpacking, electrolyte-permeable bed has a tapered cell cavity bounded by two nonparallel surfaces separated by a distance that promotes bridging of particles across the cavity. The gap/particle size ratio is maintained as the particles are consumed, decrease in size, and travel from the point of entry to the narrower end of the cell. A cell of this configuration supports a bed of low packing density maintained in a dynamic steady state by alternate formation and collapse of particle bridges across the gap and associated voids over the entire active area of the cell. The cell design can be applied to refuelable zinc/air cells and zinc/ferrocyanide storage batteries. 6 figs.

Continuous aryl alcohol oxidase production under growth-limited conditions using a trickle bed reactor.

PubMed

Pardo-Planas, Oscar; Atiyeh, Hasan K; Prade, Rolf A; Müller, Michael; Wilkins, Mark R

2018-05-01

An A. nidulans strain with a pyridoxine marker was used for continuous production of aryl alcohol oxidase (AAO) in a trickle bed reactor (TBR). Modified medium with reduced zinc, no copper, and 5 g/L ascorbic acid that reduced melanin production and increased AAO productivity under growth limited conditions was used. Two air flow rates, 0.11 L/min (0.1 vvm) and 1.1 L/min (1.0 vvm) were tested. More melanin formation and reduced protein productivity were observed with air flow rate of 1.1 L/min. Three random packings were used as support for the fungus inside the TBR column, two of which were hydrophobic and one which was hydrophilic, and three different dilution rates were tested. The use of GEA BCN 030 hydrophobic packing resulted in greater AAO yield and productivity than the other packings. Increasing dilution rates favored melanin formation and citric, lactic and succinic acid accumulation, which decreased AAO yield and productivity. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterization of the mechanical behavior of sea ice as a frictional material

NASA Astrophysics Data System (ADS)

Lade, Poul V.

2002-12-01

The mechanical properties of sea ice are determined by the formation process, and the consequent material behavior at the element scale exhibits viscoelastic behavior at the early loading stages, followed by brittle fracture or ductile, irrecoverable deformation that may be captured by hardening/softening plasticity models with nonassociated flow. Failure of sea ice under different loading conditions follows a pattern that demonstrates its highly cross-anisotropic nature as well as its behavior as a frictional material. The interactions between the floes in the pack ice resemble those observed in granular materials. These materials are frictional in nature, they exhibit both contractive and dilative volume changes, the plastic flow is nonassociated, and their stiffnesses and strengths increase with confining pressure, but they do not have any strength when unconfined. The overall behavior of the pack ice may be close to isotropic. Constitutive modeling of this behavior may be achieved by models used in geotechnical engineering. Formation of leads and subsequent freezing of the water results in cementation between the ice floes, and the pack ice becomes stronger. The behavior of the pack ice may now be compared with that observed in cemented soils or concrete. For these materials, increasing amounts of cementation result in increasing rates of dilation when sheared, and this accounts for the largest contribution to the increase in shear strength.

Effect of questionnaire length, personalisation and reminder type on response rate to a complex postal survey: randomised controlled trial

PubMed Central

2011-01-01

Background Minimising participant non-response in postal surveys helps to maximise the generalisability of the inferences made from the data collected. The aim of this study was to examine the effect of questionnaire length, personalisation and reminder type on postal survey response rate and quality and to compare the cost-effectiveness of the alternative survey strategies. Methods In a pilot study for a population study of travel behaviour, physical activity and the environment, 1000 participants sampled from the UK edited electoral register were randomly allocated using a 2 × 2 factorial design to receive one of four survey packs: a personally addressed long (24 page) questionnaire pack, a personally addressed short (15 page) questionnaire pack, a non-personally addressed long questionnaire pack or a non-personally addressed short questionnaire pack. Those who did not return a questionnaire were stratified by initial randomisation group and further randomised to receive either a full reminder pack or a reminder postcard. The effects of the survey design factors on response were examined using multivariate logistic regression. Results An overall response rate of 17% was achieved. Participants who received the short version of the questionnaire were more likely to respond (OR = 1.48, 95% CI 1.06 to 2.07). In those participants who received a reminder, personalisation of the survey pack and reminder also increased the odds of response (OR = 1.44, 95% CI 1.01 to 1.95). Item non-response was relatively low, but was significantly higher in the long questionnaire than the short (9.8% vs 5.8%; p = .04). The cost per additional usable questionnaire returned of issuing the reminder packs was £23.1 compared with £11.3 for the reminder postcards. Conclusions In contrast to some previous studies of shorter questionnaires, this trial found that shortening a relatively lengthy questionnaire significantly increased the response. Researchers should consider the trade off between the value of additional questions and a larger sample. If low response rates are expected, personalisation may be an important strategy to apply. Sending a full reminder pack to non-respondents appears a worthwhile, albeit more costly, strategy. PMID:21548947

Physical stability and resistance to peroxidation of a range of liquid-fill hard gelatin capsule products on extreme long-term storage.

PubMed

Bowtle, William; Kanyowa, Lionel; Mackenzie, Mark; Higgins, Paul

2011-06-01

The industrial take-up of liquid-fill hard capsule technology is limited in part by lack of published long-term physical and chemical stability data which demonstrate the robustness of the system. To assess the effects of extreme long-term storage on liquid-fill capsule product quality and integrity, with respect to both the capsules per se and a standard blister-pack type (foil-film blister). Fourteen sets of stored peroxidation-sensitive liquid-fill hard gelatin capsule product samples, originating ~20 years from the current study, were examined with respect to physical and selected chemical properties, together with microbiological evaluation. All sets retained physical integrity of capsules and blister-packs. Capsules were free of leaks, gelatin cross-linking, and microbiological growth. Eight samples met a limit (anisidine value, 20) commonly used as an index of peroxidation for lipid-based products with shelf lives of 2-3 years. Foil-film blister-packs using PVC or PVC-PVdC as the thermoforming film were well-suited packaging components for the liquid-fill capsule format. The study confirms the long-term physical robustness of the liquid-fill hard capsule format, together with its manufacturing and banding processes. It also indicates that various peroxidation-sensitive products using the capsule format may be maintained satisfactorily over very prolonged storage periods.

A fungal biofilm reactor based on metal structured packing improves the quality of a Gla::GFP fusion protein produced by Aspergillus oryzae.

PubMed

Zune, Q; Delepierre, A; Gofflot, S; Bauwens, J; Twizere, J C; Punt, P J; Francis, F; Toye, D; Bawin, T; Delvigne, F

2015-08-01

Fungal biofilm is known to promote the excretion of secondary metabolites in accordance with solid-state-related physiological mechanisms. This work is based on the comparative analysis of classical submerged fermentation with a fungal biofilm reactor for the production of a Gla::green fluorescent protein (GFP) fusion protein by Aspergillus oryzae. The biofilm reactor comprises a metal structured packing allowing the attachment of the fungal biomass. Since the production of the target protein is under the control of the promoter glaB, specifically induced in solid-state fermentation, the biofilm mode of culture is expected to enhance the global productivity. Although production of the target protein was enhanced by using the biofilm mode of culture, we also found that fusion protein production is also significant when the submerged mode of culture is used. This result is related to high shear stress leading to biomass autolysis and leakage of intracellular fusion protein into the extracellular medium. Moreover, 2-D gel electrophoresis highlights the preservation of fusion protein integrity produced in biofilm conditions. Two fungal biofilm reactor designs were then investigated further, i.e. with full immersion of the packing or with medium recirculation on the packing, and the scale-up potentialities were evaluated. In this context, it has been shown that full immersion of the metal packing in the liquid medium during cultivation allows for a uniform colonization of the packing by the fungal biomass and leads to a better quality of the fusion protein.

The Function of Emulsions on the Biogenic Amine Formation and their Indices of Sea Bass Fillets (Dicentrarchus Labrax) Stored in Vacuum Packaging.

PubMed

Ozogul, Yesim; Durmus, Mustafa; Kuley Boga, Esmeray; Uçar, Yılmaz; Ozogul, Fatih

2018-02-01

The impacts of emulsions based on commercial oils on the biogenic amine formation and their indices of vacuumed packed sea bass fillets were investigated. The results showed that among biogenic amines, cadaverine, putrescine, spermidine, spermine, serotonin, dopamine, and agmatine were predominant amines in sea bass fillets stored under vacuum packaging. Significant differences (P < 0.05) in biogenic amines concentrations of vacuumed packed sea bass treated with emulsions were observed. All groups contained histamine lower than 5.0 mg/100 g, regarded as the allowable limit by the U.S. Food and Drug Administration. Polyamine levels were not affected by application of emulsion. Quality index (QI) showed an increase and after 14 d of storage it decreased in all groups. The control generally seemed to higher QI value than those of treatment groups except at 14 and 18 days while soybean and corn gave lower QI among treatment groups. Only biogenic amine index correlated with sensory acceptability of vacuumed packed sea bass, indicating that this index can be used for determination of the degree of spoilage of vacuumed packed sea bass. Emulsions extended the shelf-life (approximately 2 to 4 d) of vacuumed packed sea bass fillets by inhibiting microbial growth compared to the control. Emulsions have become popular since they are regarded as ideal carrier for the delivery of lipophilic substances due to the ease of preparation, small particle size, their enhanced bioavailability, and long term kinetic stability. They have been proven to be self-preserving antimicrobials due to bound water in their structure and thus no available water to microorganisms. Antimicrobial emulsions have potential applications in many fields because they are inexpensive, stable, and nontoxic agents. © 2018 Institute of Food Technologists®.

Homogenized modeling methodology for 18650 lithium-ion battery module under large deformation

PubMed Central

Tang, Liang; Cheng, Pengle

2017-01-01

Effective lithium-ion battery module modeling has become a bottleneck for full-size electric vehicle crash safety numerical simulation. Modeling every single cell in detail would be costly. However, computational accuracy could be lost if the module is modeled by using a simple bulk material or rigid body. To solve this critical engineering problem, a general method to establish a computational homogenized model for the cylindrical battery module is proposed. A single battery cell model is developed and validated through radial compression and bending experiments. To analyze the homogenized mechanical properties of the module, a representative unit cell (RUC) is extracted with the periodic boundary condition applied on it. An elastic–plastic constitutive model is established to describe the computational homogenized model for the module. Two typical packing modes, i.e., cubic dense packing and hexagonal packing for the homogenized equivalent battery module (EBM) model, are targeted for validation compression tests, as well as the models with detailed single cell description. Further, the homogenized EBM model is confirmed to agree reasonably well with the detailed battery module (DBM) model for different packing modes with a length scale of up to 15 × 15 cells and 12% deformation where the short circuit takes place. The suggested homogenized model for battery module makes way for battery module and pack safety evaluation for full-size electric vehicle crashworthiness analysis. PMID:28746390

Homogenized modeling methodology for 18650 lithium-ion battery module under large deformation.

PubMed

Tang, Liang; Zhang, Jinjie; Cheng, Pengle

2017-01-01

Effective lithium-ion battery module modeling has become a bottleneck for full-size electric vehicle crash safety numerical simulation. Modeling every single cell in detail would be costly. However, computational accuracy could be lost if the module is modeled by using a simple bulk material or rigid body. To solve this critical engineering problem, a general method to establish a computational homogenized model for the cylindrical battery module is proposed. A single battery cell model is developed and validated through radial compression and bending experiments. To analyze the homogenized mechanical properties of the module, a representative unit cell (RUC) is extracted with the periodic boundary condition applied on it. An elastic-plastic constitutive model is established to describe the computational homogenized model for the module. Two typical packing modes, i.e., cubic dense packing and hexagonal packing for the homogenized equivalent battery module (EBM) model, are targeted for validation compression tests, as well as the models with detailed single cell description. Further, the homogenized EBM model is confirmed to agree reasonably well with the detailed battery module (DBM) model for different packing modes with a length scale of up to 15 × 15 cells and 12% deformation where the short circuit takes place. The suggested homogenized model for battery module makes way for battery module and pack safety evaluation for full-size electric vehicle crashworthiness analysis.

Material selection and assembly method of battery pack for compact electric vehicle

NASA Astrophysics Data System (ADS)

Lewchalermwong, N.; Masomtob, M.; Lailuck, V.; Charoenphonphanich, C.

2018-01-01

Battery packs become the key component in electric vehicles (EVs). The main costs of which are battery cells and assembling processes. The battery cell is indeed priced from battery manufacturers while the assembling cost is dependent on battery pack designs. Battery pack designers need overall cost as cheap as possible, but it still requires high performance and more safety. Material selection and assembly method as well as component design are very important to determine the cost-effectiveness of battery modules and battery packs. Therefore, this work presents Decision Matrix, which can aid in the decision-making process of component materials and assembly methods for a battery module design and a battery pack design. The aim of this study is to take the advantage of incorporating Architecture Analysis method into decision matrix methods by capturing best practices for conducting design architecture analysis in full account of key design components critical to ensure efficient and effective development of the designs. The methodology also considers the impacts of choice-alternatives along multiple dimensions. Various alternatives for materials and assembly techniques of battery pack are evaluated, and some sample costs are presented. Due to many components in the battery pack, only seven components which are positive busbar and Z busbar are represented in this paper for using decision matrix methods.

Molecular Association and Monolayer Formation of Soluble Phthalocyanine Compounds.

DTIC Science & Technology

1983-04-20

stable Langmuir - Blodgett monolayer to film pressures of 20 mN/m ant force-area curves indicate a dense packing of phthalocyanine units with molecular areas...8217which is monomeric and Cu, Ni, Pd and PtpdX4 wMyi,chjform larger complexes ranging from 2.7 to 4.1 molecular units. EachU.MCx*4 forms a stable Langmuir ... Blodgett monolayer to film pressures of 20 mN/in and force-area curves indicate a dense packing of phthalocyanine urits with molecul-ar areas

Polydisperse sphere packing in high dimensions, a search for an upper critical dimension

NASA Astrophysics Data System (ADS)

Morse, Peter; Clusel, Maxime; Corwin, Eric

2012-02-01

The recently introduced granocentric model for polydisperse sphere packings has been shown to be in good agreement with experimental and simulational data in two and three dimensions. This model relies on two effective parameters that have to be estimated from experimental/simulational results. The non-trivial values obtained allow the model to take into account the essential effects of correlations in the packing. Once these parameters are set, the model provides a full statistical description of a sphere packing for a given polydispersity. We investigate the evolution of these effective parameters with the spatial dimension to see if, in analogy with the upper critical dimension in critical phenomena, there exists a dimension above which correlations become irrelevant and the model parameters can be fixed a priori as a function of polydispersity. This would turn the model into a proper theory of polydisperse sphere packings at that upper critical dimension. We perform infinite temperature quench simulations of frictionless polydisperse sphere packings in dimensions 2-8 using a parallel algorithm implemented on a GPGPU. We analyze the resulting packings by implementing an algorithm to calculate the additively weighted Voronoi diagram in arbitrary dimension.

Comparisons of ice packs, hot water immersion, and analgesia injection for the treatment of centipede envenomations in Taiwan.

PubMed

Chaou, Chung-Hsien; Chen, Chian-Kuang; Chen, Jih-Chang; Chiu, Te-Fa; Lin, Chih-Chuan

2009-08-01

To compare the effectiveness of ice packs and hot water immersion for the treatment of centipede envenomations. Sixty patients envenomated by centipedes were randomized into three groups and were treated with ice packs, hot water immersion, or analgesia injection. The visual analog score (VAS) for pain was measured before the treatment and 15 min afterward. Demographic data and data on local and systemic effects after centipede bites were collected. The VAS scores and the pain decrease (DeltaVAS) were compared between the three groups. All patients suffered from pain at the affected sites; other local effects included redness (n = 49, 81.7%), swelling (n = 32, 53.3%), heat (n = 14, 23.3%), itchiness (n = 5, 8.3), and bullae formation (n = 3, 5.0%). Rare systemic effects were reported. All three groups had similar VAS scores before and after treatment. They also had similar effectiveness in reducing pain caused by centipedes bites (DeltaVAS = 2.55 +/- 1.88, 2.33 +/- 1.78, and 1.55 +/- 1.68, with ice packs, analgesia, and hot water immersion, respectively, p = 0.165). Ice packs, hot water immersion, and analgesics all improved the pain from centipede envenomation. Ice pack treatment is a safe, inexpensive, and non-invasive method for pre-hospital management in patients with centipede envenomation.

Ferric Oxide Mediated Formation of PCDD/Fs from 2-Monochlorophenol

PubMed Central

Nganai, Shadrack; Lomnicki, Slawo; Dellinger, Barry

2012-01-01

The copper oxide, surface-mediated formation of polychlorinated dibenzop-dioxins and dibenzofurans (PCDD/F) from precursors such as chlorinated phenols is considered to be a major source of PCDD/F emissions from combustion sources. In spite of being present at 2–50x higher concentrations than copper oxide, virtually no studies of the iron oxide-mediated formation of PCDD/F have been reported in the literature. We have performed packed bed, flow reactor studies of the reaction of 50 ppm gas phase 2-monochlorophenol (2-MCP) over a surface of 5% iron oxide on silica over a temperature range of 200–500 °C. Dibenzo-p-dioxin (DD), 1-monochlorodibenzo-p-dioxin (1-MCDD), 4,6-dichlorodibenzofuran (4,6-DCDF), and dibenzofuran (DF) were formed in maximum yields of 0.1, 0.2, 0.3, and 0.4 %, respectively. The yield of PCDD/F over iron oxide peaked at temperatures 50–100 °C higher in temperature than over copper oxide. The maximum yields of DD, 1-MCDD and 4,6-DCDF were 2x and 5x higher over iron oxide, respectively, than over copper oxide, while DF was not observed at all for copper oxide. The resulting PCDD/PCDF ratio was 0.39 versus 1.2 observed for iron oxide and copper oxide, respectively, which is in agreement with PCDD to PCDF ratios in full-scale combustors that are typically ≪1. The combination of 2–50x higher concentrations of iron oxide than copper oxide in most full-scale combustors and 2.5x higher yields of PCDD/F observed in the laboratory, suggest that iron oxide may contribute as much as 5–125x more than copper oxide to the emissions of PCDD/F from full-scale combustors. PMID:19238966

Crystallization of micrometer-sized particles with molecular contours.

PubMed

Song, Pengcheng; Olmsted, Brian K; Chaikin, Paul; Ward, Michael D

2013-11-12

The crystallization of micrometer-sized particles with shapes mimicking those of tetrabenzoheptacene (TBH) and 1,2:5,6-dibenzanthracene (DBT), both flat polyacenes, in an electric field results in the formation of ordered 2D packings that mimic the plane group symmetries in their respective molecular crystal equivalents. Whereas the particles packed in low-density disordered arrangements under a gravitational gradient, dielectrophoresis (under an ac electric field) produced ordered high-density packings with readily identifiable plane group symmetry. The ordered colloidal assemblies were stable for hours, with the packing density decreasing slowly but with recognizable symmetry for up to 12 h for the TBH-shaped particles and up to 4 h for the DBT-shaped particles. This unexpected stability is attributed to jamming behavior associated with interlocking of the dogbone-shaped (TBH) and Z-block (DBT) particles, contrasting with the more rapid reduction of packing density and loss of hexagonal symmetry for disk-shaped particles upon removal of the electric field. The TBH-shaped and DBT-shaped particles assemble into the p2 plane group, which corresponds to the densest particle packing among the possible close-packed plane groups for these particle symmetries. The p2 symmetry observed for the TBH-shaped and DBT-shaped colloid crystal emulates the p2 symmetry of the (010) layers in their respective molecular crystals, which crystallize in monoclinic lattices. Notably, DBT-shaped particles also form ordered domains with pgg symmetry, replicating the plane group symmetry of the (100) layer in the orthorhombic polymorph of DBT. These observations illustrate that the 2D ordering of colloid particles can mimic the packing of molecules with similar shapes, demonstrating that packing can transcend length scales from the molecular to the colloidal.

Effect of Current and SOC on Round-Trip Energy Efficiency of a Lithium-Iron Phosphate (LiFePO4) Battery Pack (SAE Paper 2015-01-1186)

EPA Science Inventory

While equivalent circuit modeling is an effective way to model the performance and energy efficiency of automotive Li-ion batteries, in some applications it is more convenient to refer directly to round-trip energy efficiency. Energy efficiency of either cells or full packs is se...

Morphological and Compositional (S)TEM Analysis of Multiple Exciton Generation Solar Cells

NASA Astrophysics Data System (ADS)

Wisnivesky-Rocca-Rivarola, F.; Davis, N. J. L. K.; Bohm, M.; Ducati, C.

2015-10-01

Quantum confinement of charge carriers in semiconductor nanocrystals produces optical and electronic properties that have the potential to enhance the power conversion efficiency of solar cells. One of these properties is the efficient formation of more than one electron-hole pair from a single absorbed photon, in a process called multiple exciton generation (MEG). In this work we studied the morphology of nanocrystal multilayers of PbSe treated with CdCl2 using complementary imaging and spectroscopy techniques to characterise the chemical composition and morphology of full MEG devices made with PbSe nanorods (NRs). IN the scanning TEM (STEM), plan view images and chemical maps were obtained of the nanocrystal layers, which allowed for the analysis of crystal structure and orientation, as well as size distribution and aspect ratio. These results were complemented by cross-sectional images of full devices, which allowed accessing the structure of each layer that composes the device, including the nanorod packing in the active nanocrystal layer.

Packing interface energetics in different crystal forms of the λ Cro dimer.

PubMed

Ahlstrom, Logan S; Miyashita, Osamu

2014-07-01

Variation among crystal structures of the λ Cro dimer highlights conformational flexibility. The structures range from a wild type closed to a mutant fully open conformation, but it is unclear if each represents a stable solution state or if one may be the result of crystal packing. Here we use molecular dynamics (MD) simulation to investigate the energetics of crystal packing interfaces and the influence of site-directed mutagenesis on them in order to examine the effect of crystal packing on wild type and mutant Cro dimer conformation. Replica exchange MD of mutant Cro in solution shows that the observed conformational differences between the wild type and mutant protein are not the direct consequence of mutation. Instead, simulation of Cro in different crystal environments reveals that mutation affects the stability of crystal forms. Molecular Mechanics Poisson-Boltzmann Surface Area binding energy calculations reveal the detailed energetics of packing interfaces. Packing interfaces can have diverse properties in strength, energetic components, and some are stronger than the biological dimer interface. Further analysis shows that mutation can strengthen packing interfaces by as much as ∼5 kcal/mol in either crystal environment. Thus, in the case of Cro, mutation provides an additional energetic contribution during crystal formation that may stabilize a fully open higher energy state. Moreover, the effect of mutation in the lattice can extend to packing interfaces not involving mutation sites. Our results provide insight into possible models for the effect of crystallization on Cro conformational dynamics and emphasize careful consideration of protein crystal structures. © 2013 Wiley Periodicals, Inc.

Packing Interface Energetics in Different Crystal Forms of the λ Cro Dimer

PubMed Central

Ahlstrom, Logan S.; Miyashita, Osamu

2014-01-01

Variation among crystal structures of the λ Cro dimer highlights conformational flexibility. The structures range from a wild type closed to a mutant fully open conformation, but it is unclear if each represents a stable solution state or if one may be the result of crystal packing. Here we use molecular dynamics (MD) simulation to investigate the energetics of crystal packing interfaces and the influence of site-directed mutagenesis on them, in order to examine the effect of crystal packing on wild type and mutant Cro dimer conformation. Replica exchange MD of mutant Cro in solution shows that the observed conformational differences between the wild type and mutant protein are not the direct consequence of mutation. Instead, simulation of Cro in different crystal environments reveals that mutation affects the stability of crystal forms. Molecular Mechanics Poisson-Boltzmann Surface Area binding energy calculations reveal the detailed energetics of packing interfaces. Packing interfaces can have diverse properties in strength, energetic components, and some are stronger than the biological dimer interface. Further analysis shows that mutation can strengthen packing interfaces by as much as ~5 kcal/mol in either crystal environment. Thus, in the case of Cro, mutation provides an additional energetic contribution during crystal formation that may stabilize a fully open higher energy state. Moreover, the effect of mutation in the lattice can extend to packing interfaces not involving mutation sites. Our results provide insight into possible models for the effect of crystallization on Cro conformational dynamics and emphasize careful consideration of protein crystal structures. PMID:24218107

DOE Office of Scientific and Technical Information (OSTI.GOV)

Becker, Verena; Sengupta, D; Ketteler, Robin

The formation of signal-promoting dimeric or oligomeric receptor complexes at the cell surface is modulated by self-interaction of their transmembrane (TM) domains. To address the importance of TM domain packing density for receptor functionality, we examined a set of asparagine mutants in the TM domain of the erythropoietin receptor (EpoR). We identified EpoR-T242N as a receptor variant that is present at the cell surface similar to wild-type EpoR but lacks visible localization in vesicle-like structures and is impaired in efficient activation of specific signaling cascades. Analysis by a molecular modeling approach indicated an increased interhelical distance for the EpoR-T242N TMmore » dimer. By employing the model, we designed additional mutants with increased or decreased packing volume and confirmed a correlation between packing volume and biological responsiveness. These results propose that the packing density of the TM domain provides a novel layer for fine-tuned regulation of signal transduction and cellular decisions.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuz'mina, L. G.; Fedorova, O. A.; Andryukhina, E. N.

A comparative study of the molecular geometry and crystal packing of crown-containing styryl heterocycles and their dimethoxy substituted analogues is performed. It is established that all the compounds exhibit an identical type of distortions of the geometry of the central styryl fragment. These are the localization of the {pi}-electron density at the ethylene bond and the bond alternation in a half of the phenyl ring due to the conjugation of lone electron pairs of the oxygen substituents with the chromophore system of the molecule. A comparative analysis of the crystal packings of the compounds reveals extended separate hydrophilic and hydrophobicmore » regions. The hydrophilic regions are built of crown ether fragments, and the hydrophobic regions consist of {pi}-conjugated and aromatic molecular fragments. The hydrophobic regions are characterized by a wide variety of packing motifs, among which stacking packing is absent. For two compounds, the formation of sandwich dimers that are preorganized to enter into the photochemical [2 + 2]cycloaddition reaction is observed.« less

Preparation and Characterization of Ato Nanoparticles by Coprecipitation with Modified Drying Method

NASA Astrophysics Data System (ADS)

Liu, Shimin; Liang, Dongdong; Liu, Jindong; Jiang, Weiwei; Liu, Chaoqian; Ding, Wanyu; Wang, Hualin; Wang, Nan

Antimony-doped tin oxide (ATO) nanoparticles were prepared by coprecipitation by packing drying and traditional direct drying (for comparison) methods. The as-prepared ATO nanoparticles were characterized by TG, XRD, EDS, TEM, HRTEM, BET, bulk density and electrical resistivity measurements. Results indicated that the ATO nanoparticles obtained by coprecipitation with direct drying method featured hard-agglomerated morphology, high bulk density, low surface area and low electrical resistivity, probably due to the direct liquid evaporation during drying, the fast shrinkage of the precipitate, the poor removal efficiency of liquid molecules and the hard agglomerate formation after calcination. Very differently, the ATO product obtained by the packing and drying method featured free-agglomerated morphology, low bulk density, high surface area and high electrical resistivity ascribed probably to the formed vapor cyclone environment and liquid evaporation-resistance, avoiding fast liquid removal and improving the removal efficiency of liquid molecules. The intrinsic formation mechanism of ATO nanoparticles from different drying methods was illustrated based on the dehydration process of ATO precipitates. Additionally, the packing and drying time played key roles in determining the bulk density, morphology and electrical conductivity of ATO nanoparticles.

How the morphology of dusts influences packing density in small solar system bodies

NASA Astrophysics Data System (ADS)

Zangmeister, C.; Radney, J. G.; Zachariah, M. R.

2014-12-01

Large planetary seedlings, comets, and nanoscale soot particles are made from rigid, aggregated subunits that are compacted under low compression into larger structures spanning over 10 orders of magnitude in dimensional space. Here, we demonstrate that the packing density (Φf) of compacted rigid aggregates is independent of spatial scale for systems under weak compaction, a regime that includes small solar system bodies. The Φf of rigid aggregated structures across 6 orders of magnitude were measured using nanoscale spherical soot aerosol composed of aggregates with ≈ 17 nm monomeric subunits and aggregates made from uniform monomeric 6 mm spherical subunits at the macroscale. We find Φf = 0.36 ± 0.02 at both the nano- and macroscale. These values are remarkably similar to qf observed for comet nuclei and measured values of other rigid aggregated systems across a wide variety of spatial and formative conditions. We present a packing model that incorporates the aggregate morphology and show that Φf is independent of both monomer and aggregate size. These observations suggest thatqf of rigid aggregates is independent of spatial dimension across varied formative conditions ranging from interstellar space to pharmaceutical manufacturing.

Column-to-column packing variation of disposable pre-packed columns for protein chromatography.

PubMed

Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois

2017-12-08

In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

The "sugar pack" health marketing campaign in Los Angeles County, 2011-2012.

PubMed

Barragan, Noel C; Noller, Ali J; Robles, Brenda; Gase, Lauren N; Leighs, Michael S; Bogert, Suzanne; Simon, Paul A; Kuo, Tony

2014-03-01

As part of a comprehensive approach to combating the obesity epidemic, the Los Angeles County Department of Public Health launched the "Sugar Pack" health marketing campaign in fall 2011. Carried out in three stages, the campaign sought to educate and motivate the public to reduce excess calorie intake from sugar-sweetened beverage consumption. The primary Sugar Pack creative concepts provided consumers with information about the number of sugar packs contained in sugary drinks. Data from formative market research as well as lessons from previous campaigns in other U.S. jurisdictions informed the development of the materials. These materials were disseminated through a multipronged platform that included paid outdoor media on transit and billboards and messaging using social media (i.e., Twitter, Facebook, YouTube, and sendable e-cards). Initial findings from a postcampaign assessment indicate that the Sugar Pack campaign reached broadly into targeted communities, resulting in more than 515 million impressions. Lessons learned from the campaign suggest that employing health marketing to engage the public can lead to increased knowledge, favorable recognition of health messages, and self-reported intention to reduce sugar-sweetened beverage consumption, potentially complementing other obesity prevention strategies in the field.

Vortex circulation and polarity patterns in closely packed cap arrays

DOE PAGES

Streubel, Robert; Kronast, Florian; Reiche, Christopher F.; ...

2016-01-25

For this work, we studied curvature-driven modifications to the magnetostatic coupling of vortex circulation and polarity in soft-magnetic closely packed cap arrays. A phase diagram for the magnetic remanent/transition states at room temperature as a function of diameter and thickness was assembled. For specimens with vortex remanent state (40 nm-thick Permalloy on 330 nm spherical nanoparticles), both vortex circulation and polarity were visualized. Intercap coupling upon vortex nucleation leads to the formation of vortex circulation patterns in closely packed arrays. The remanent circulation pattern can be tailored choosing the direction of the applied magnetic field with respect to the symmetrymore » axis of the hexagonal array. An even and random distribution of vortex polarity indicates the absence of any circulation-polarity coupling.« less

The Action-Packed Centaurus A

NASA Image and Video Library

2012-04-04

This parallelogram shaped region of dust observed by ESA Herschel Space telescope can be best described using galaxy formation models where a flat spiral galaxy collides with an elliptical galaxy becoming warped in the process.

Controlled irrigation of a structured packing as a method for increasing the efficiency of liquid mixture separation in the distillation column

NASA Astrophysics Data System (ADS)

Pavlenko, A. N.; Zhukov, V. E.; Pecherkin, N. I.; Nazarov, A. D.; Li, X.; Li, H.; Gao, X.; Sui, H.

2017-09-01

The use of modern structured packing in the distillation columns allows much more even distribution of the liquid film over the packing surface, but it does not completely solve the problem of uniform distribution of flow parameters over the entire height of the packing. Negative stratification of vapor along the packing height caused by different densities of vapor mixture components and higher temperature in the lower part of the column leads to formation of large-scale maldistributions of temperature and mixture composition over the column cross-section even under the conditions of uniform irrigation of packing with liquid. In these experiments, the idea of compensatory action of liquid distributor on the large-scale maldistribution of mixture composition over the column cross-section was implemented. The experiments were carried out in the distillation column with the diameter of 0.9 m on 10 layers of the Mellapak 350Y packing with the total height of 2.1 m. The mixture of R-21 and R-114 was used as the working mixture. To irrigate the packing, the liquid distributorr with 126 independently controlled solenoid valves overlapping the holes with the diameter of 5 mm, specially designed by the authors, was used. Response of the column to the action of liquid distributor was observed in real time according to the indications of 3 groups of thermometers mounted in 3 different cross-sections of the column. The experiments showed that the minimal correction of the drip point pattern in the controlled liquid distributor can significantly affect the pattern of flow parameter distribution over the cross-section and height of the mass transfer surface and increase separation efficiency of the column within 20%.

A novel bench-scale column assay to investigate site-specific nitrification biokinetics in biological rapid sand filters.

PubMed

Tatari, K; Smets, B F; Albrechtsen, H-J

2013-10-15

A bench-scale assay was developed to obtain site-specific nitrification biokinetic information from biological rapid sand filters employed in groundwater treatment. The experimental set-up uses granular material subsampled from a full-scale filter, packed in a column, and operated with controlled and continuous hydraulic and ammonium loading. Flowrates and flow recirculation around the column are chosen to mimic full-scale hydrodynamic conditions, and minimize axial gradients. A reference ammonium loading rate is calculated based on the average loading experienced in the active zone of the full-scale filter. Effluent concentrations of ammonium are analyzed when the bench-scale column is subject to reference loading, from which removal rates are calculated. Subsequently, removal rates above the reference loading are measured by imposing short-term loading variations. A critical loading rate corresponding to the maximum removal rate can be inferred. The assay was successfully applied to characterize biokinetic behavior from a test rapid sand filter; removal rates at reference loading matched those observed from full-scale observations, while a maximum removal capacity of 6.9 g NH4(+)-N/m(3) packed sand/h could easily be determined at 7.5 g NH4(+)-N/m(3) packed sand/h. This assay, with conditions reflecting full-scale observations, and where the biological activity is subject to minimal physical disturbance, provides a simple and fast, yet powerful tool to gain insight in nitrification kinetics in rapid sand filters. Copyright © 2013 Elsevier Ltd. All rights reserved.

Shear Roll Mill Reactivation

DTIC Science & Technology

2012-09-13

pneumatically operated paste dumper and belt conveyor system, the loss in weight feeder system, the hydraulically operated shear roll mill, the pellet...out feed belt conveyor , and the pack out system comprised of the metal detector, scale, and pack out empty and full drum roller conveyors . Page | 4...feed hopper and conveyor supplying the loss in weight feeder were turned on, and it was verified that these items functioned as designed . The

Inhibitors of amyloid toxicity based on β-sheet packing of Aβ40 and Aβ42

PubMed Central

Sato, Takeshi; Kienlen-Campard, Pascal; Ahmed, Mahiuddin; Liu, Wei; Li, Huilin; Elliott, James I.; Aimoto, Saburo; Constantinescu, Stefan N.; Octave, Jean-Noel; Smith, Steven O.

2008-01-01

Amyloid fibrils associated with Alzheimer’s disease and a wide range of other neurodegenerative diseases have a cross β-sheet structure where main chain hydrogen bonding occurs between β-strands in the direction of the fibril axis. The surface of the β-sheet has pronounced ridges and grooves when the individual β-strands have a parallel orientation and the amino acids are in-register with one another. Here we show that in Aβ amyloid fibrils, Met35 packs against Gly33 in the C-terminus of Aβ40 and against Gly37 in the C-terminus of Aβ42. These packing interactions suggest that the protofilament subunits are displaced relative to one another in the Aβ40 and Aβ42 fibril structures. We take advantage of this corrugated structure to design a new class of inhibitors that prevent fibril formation by placing alternating glycine and aromatic residues on one face of a β-strand. We show that peptide inhibitors based on a GxFxGxF framework disrupt sheet-to-sheet packing and inhibit the formation of mature Aβ fibrils as assayed by thioflavin T fluorescence, electron microscopy and solid-state NMR spectroscopy. The alternating large and small amino acids in the GxFxGxF sequence are complementary to the corresponding amino acids in the IxGxMxG motif found in the C-terminal sequence of Aβ40 and Aβ42. Importantly, the designed peptide inhibitors significantly reduce the toxicity induced by Aβ42 on cultured rat cortical neurons. PMID:16634632

Molecular interactions within the halophilic, thermophilic, and mesophilic prokaryotic ribosomal complexes: clues to environmental adaptation.

PubMed

Mallik, Saurav; Kundu, Sudip

2015-01-01

Using the available crystal structures of 50S ribosomal subunits from three prokaryotic species: Escherichia coli (mesophilic), Thermus thermophilus (thermophilic), and Haloarcula marismortui (halophilic), we have analyzed different structural features of ribosomal RNAs (rRNAs), proteins, and of their interfaces. We have correlated these structural features with the environmental adaptation strategies of the corresponding species. While dense intra-rRNA packing is observed in thermophilic, loose intra-rRNA packing is observed in halophilic (both compared to mesophilic). Interestingly, protein-rRNA interfaces of both the extremophiles are densely packed compared to that of the mesophilic. The intersubunit bridge regions are almost devoid of cavities, probably ensuring the proper formation of each bridge (by not allowing any loosely packed region nearby). During rRNA binding, the ribosomal proteins experience some structural transitions. Here, we have analyzed the intrinsically disordered and ordered regions of the ribosomal proteins, which are subjected to such transitions. The intrinsically disordered and disorder-to-order transition sites of the thermophilic and mesophilic ribosomal proteins are simultaneously (i) highly conserved and (ii) slowly evolving compared to rest of the protein structure. Although high conservation is observed at such sites of halophilic ribosomal proteins, but slow rate of evolution is absent. Such differences between thermophilic, mesophilic, and halophilic can be explained from their environmental adaptation strategy. Interestingly, a universal biophysical principle evident by a linear relationship between the free energy of interface formation, interface area, and structural changes of r-proteins during assembly is always maintained, irrespective of the environmental conditions.

Fine-Tuning Nanoparticle Packing at Water-Oil Interfaces Using Ionic Strength.

PubMed

Chai, Yu; Lukito, Alysia; Jiang, Yufeng; Ashby, Paul D; Russell, Thomas P

2017-10-11

Nanoparticle-surfactants (NPSs) assembled at water-oil interfaces can significantly lower the interfacial tension and can be used to stabilize liquids. Knowing the formation and assembly and actively tuning the packing of these NPSs is of significant fundamental interest for the interfacial behavior of nanoparticles and of interest for water purification, drug encapsulation, enhanced oil recovery, and innovative energy transduction applications. Here, we demonstrate by means of interfacial tension measurements the high ionic strength helps the adsorption of NPSs to the water-oil interface leading to a denser packing of NPSs at the interface. With the reduction of interfacial area, the phase transitions from a "gas"-like to "liquid" to "solid" states of NPSs in two dimensions are observed. Finally, we provide the first in situ real-space imaging of NPSs at the water-oil interface by atomic force microcopy.

Formation and Combustion of Smoke in Laminar Flames

NASA Technical Reports Server (NTRS)

Schalla, Rose L; Clark, Thomas P; Mcdonald, Glen E

1954-01-01

The nature and formation of smoke and its combustion were investigated. Smoke, which consist of tiny mesomorphous crystals tightly packed into popcorn-ball-like particles that agglomerate to give filaments, was found to contain about 5 percent of the hydrogen originally present in the fuel. Factors affecting smoke formation were studied in both diffusion flames and premixed Bunsen flames. It is suggested that smoking tendency increases with increasing stability of the carbon skeleton of the molecule, as determined by relative bond strength.

Surfactant process for promoting gas hydrate formation and application of the same

DOEpatents

Rogers, Rudy E.; Zhong, Yu

2002-01-01

This invention relates to a method of storing gas using gas hydrates comprising forming gas hydrates in the presence of a water-surfactant solution that comprises water and surfactant. The addition of minor amounts of surfactant increases the gas hydrate formation rate, increases packing density of the solid hydrate mass and simplifies the formation-storage-decomposition process of gas hydrates. The minor amounts of surfactant also enhance the potential of gas hydrates for industrial storage applications.

Stacking faults and mechanisms strain-induced transformations of hcp metals (Ti, Mg) during mechanical activation in liquid hydrocarbons

NASA Astrophysics Data System (ADS)

Lubnin, A. N.; Dorofeev, G. A.; Nikonova, R. M.; Mukhgalin, V. V.; Lad'yanov, V. I.

2017-11-01

The evolution of the structure and substructure of metals Ti and Mg with hexagonal close-packed (hcp) lattice is studied during their mechanical activation in a planetary ball mill in liquid hydrocarbons (toluene, n-heptane) and with additions of carbon materials (graphite, fullerite, nanotubes) by X-ray diffraction, scanning electron microscopy, and chemical analysis. The temperature behavior and hydrogen-accumulating properties of mechanocomposites are studied. During mechanical activation of Ti and Mg, liquid hydrocarbons decay, metastable nanocrystalline titanium carbohydride Ti(C,H) x and magnesium hydride β-MgH2 are formed, respectively. The Ti(C,H) x and MgH2 formation mechanisms during mechanical activation are deformation ones and are associated with stacking faults accumulation, and the formation of face-centered cubic (fcc) packing of atoms. Metastable Ti(C,H)x decays at a temperature of 550°C, the partial reverse transformation fcc → hcp occurs. The crystalline defect accumulation (nanograin boundaries, stacking faults), hydrocarbon destruction, and mechanocomposite formation leads to the enhancement of subsequent magnesium hydrogenation in the Sieverts reactor.

Pore configuration landscape of granular crystallization.

PubMed

Saadatfar, M; Takeuchi, H; Robins, V; Francois, N; Hiraoka, Y

2017-05-12

Uncovering grain-scale mechanisms that underlie the disorder-order transition in assemblies of dissipative, athermal particles is a fundamental problem with technological relevance. To date, the study of granular crystallization has mainly focussed on the symmetry of crystalline patterns while their emergence and growth from irregular clusters of grains remains largely unexplored. Here crystallization of three-dimensional packings of frictional spheres is studied at the grain-scale using X-ray tomography and persistent homology. The latter produces a map of the topological configurations of grains within static partially crystallized packings. Using numerical simulations, we show that similar maps are measured dynamically during the melting of a perfect crystal. This map encodes new information on the formation process of tetrahedral and octahedral pores, the building blocks of perfect crystals. Four key formation mechanisms of these pores reproduce the main changes of the map during crystallization and provide continuous deformation pathways representative of the crystallization dynamics.

Pore configuration landscape of granular crystallization

PubMed Central

Saadatfar, M.; Takeuchi, H.; Robins, V.; Francois, N.; Hiraoka, Y.

2017-01-01

Uncovering grain-scale mechanisms that underlie the disorder–order transition in assemblies of dissipative, athermal particles is a fundamental problem with technological relevance. To date, the study of granular crystallization has mainly focussed on the symmetry of crystalline patterns while their emergence and growth from irregular clusters of grains remains largely unexplored. Here crystallization of three-dimensional packings of frictional spheres is studied at the grain-scale using X-ray tomography and persistent homology. The latter produces a map of the topological configurations of grains within static partially crystallized packings. Using numerical simulations, we show that similar maps are measured dynamically during the melting of a perfect crystal. This map encodes new information on the formation process of tetrahedral and octahedral pores, the building blocks of perfect crystals. Four key formation mechanisms of these pores reproduce the main changes of the map during crystallization and provide continuous deformation pathways representative of the crystallization dynamics. PMID:28497794

Pore configuration landscape of granular crystallization

NASA Astrophysics Data System (ADS)

Saadatfar, M.; Takeuchi, H.; Robins, V.; Francois, N.; Hiraoka, Y.

2017-05-01

Uncovering grain-scale mechanisms that underlie the disorder-order transition in assemblies of dissipative, athermal particles is a fundamental problem with technological relevance. To date, the study of granular crystallization has mainly focussed on the symmetry of crystalline patterns while their emergence and growth from irregular clusters of grains remains largely unexplored. Here crystallization of three-dimensional packings of frictional spheres is studied at the grain-scale using X-ray tomography and persistent homology. The latter produces a map of the topological configurations of grains within static partially crystallized packings. Using numerical simulations, we show that similar maps are measured dynamically during the melting of a perfect crystal. This map encodes new information on the formation process of tetrahedral and octahedral pores, the building blocks of perfect crystals. Four key formation mechanisms of these pores reproduce the main changes of the map during crystallization and provide continuous deformation pathways representative of the crystallization dynamics.

TVB-EduPack—An Interactive Learning and Scripting Platform for The Virtual Brain

PubMed Central

Matzke, Henrik; Schirner, Michael; Vollbrecht, Daniel; Rothmeier, Simon; Llarena, Adalberto; Rojas, Raúl; Triebkorn, Paul; Domide, Lia; Mersmann, Jochen; Solodkin, Ana; Jirsa, Viktor K.; McIntosh, Anthony Randal; Ritter, Petra

2015-01-01

The Virtual Brain (TVB; thevirtualbrain.org) is a neuroinformatics platform for full brain network simulation based on individual anatomical connectivity data. The framework addresses clinical and neuroscientific questions by simulating multi-scale neural dynamics that range from local population activity to large-scale brain function and related macroscopic signals like electroencephalography and functional magnetic resonance imaging. TVB is equipped with a graphical and a command-line interface to create models that capture the characteristic biological variability to predict the brain activity of individual subjects. To enable researchers from various backgrounds a quick start into TVB and brain network modeling in general, we developed an educational module: TVB-EduPack. EduPack offers two educational functionalities that seamlessly integrate into TVB's graphical user interface (GUI): (i) interactive tutorials introduce GUI elements, guide through the basic mechanics of software usage and develop complex use-case scenarios; animations, videos and textual descriptions transport essential principles of computational neuroscience and brain modeling; (ii) an automatic script generator records model parameters and produces input files for TVB's Python programming interface; thereby, simulation configurations can be exported as scripts that allow flexible customization of the modeling process and self-defined batch- and post-processing applications while benefitting from the full power of the Python language and its toolboxes. This article covers the implementation of TVB-EduPack and its integration into TVB architecture. Like TVB, EduPack is an open source community project that lives from the participation and contribution of its users. TVB-EduPack can be obtained as part of TVB from thevirtualbrain.org. PMID:26635597

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuz'mina, L. G., E-mail: kuzmina@igic.ras.ru; Kucherepa, N. S.; Rodnikova, M. N.

The molecular and crystal structures of two p-(alkoxybenzylidene)-p'-toluidines C{sub 5}H{sub 11}O-C{sub 6}H{sub 4}-CH=N-C{sub 6}H{sub 4}-CH{sub 3} (1) and C{sub 8}H{sub 17}O-C{sub 6}H{sub 4}-CH=N-C{sub 6}H{sub 4}-CH{sub 3} (2), which form the nematic phase upon melting, is determined by X-ray diffraction. The geometry of the benzylideneaniline fragments in molecules 1 and 2 is actually identical. The crystal packings of 1 and 2 are characterized by the alternation of layers formed by loosely packed aliphatic fragments of molecules and layers of closely packed aromatic fragments. The packing in the aromatic regions of 1 follows the parquet pattern. The crystal packing of 2 hasmore » a stacking structure, which is formed by {pi}-stacking dimers superimposed on one another. The formation of the mesogenic phase upon melting of crystals 1 is due to the disturbance of the structurality of loose aliphatic layers with retention of the structure of the aromatic regions, which are stabilized by the cooperative effect of weak directed C-H ... {pi}-system interactions. The mesogenic phase of crystals 2 is formed upon melting as a consequence of the retention of the structure of {pi}-stacking dimers.« less

Discharge Characteristics of Series Surface/Packed-Bed Discharge Reactor Diven by Bipolar Pulsed Power

NASA Astrophysics Data System (ADS)

Hu, Jian; Jiang, Nan; Li, Jie; Shang, Kefeng; Lu, Na; Wu, Yan; Mizuno, Akira

2016-03-01

The discharge characteristics of the series surface/packed-bed discharge (SSPBD) reactor driven by bipolar pulse power were systemically investigated in this study. In order to evaluate the advantages of the SSPBD reactor, it was compared with traditional surface discharge (SD) reactor and packed-bed discharge (PBD) reactor in terms of the discharge voltage, discharge current, and ozone formation. The SSPBD reactor exhibited a faster rising time and lower tail voltage than the SD and PBD reactors. The distribution of the active species generated in different discharge regions of the SSPBD reactor was analyzed by optical emission spectra and ozone analysis. It was found that the packed-bed discharge region (3.5 mg/L), rather than the surface discharge region (1.3 mg/L) in the SSPBD reactor played a more important role in ozone generation. The optical emission spectroscopy analysis indicated that more intense peaks of the active species (e.g. N2 and OI) in the optical emission spectra were observed in the packed-bed region. supported by National Natural Science Foundation of China (No. 51177007), the Joint Funds of National Natural Science Foundation of China (No. U1462105), and Dalian University of Technology Fundamental Research Fund of China (No. DUT15RC(3)030)

Modeling aerosols formed in the ring - pack of reciprocating piston

NASA Astrophysics Data System (ADS)

Dallstream, Brian Ellis

The hydrocarbon emissions of an internal combustion engine are directly correlated with the engine's oil consumption. This oil consumption is associated with reverse blow-by, a condition in which gases flow past the ring-pack from the crankcase to the combustion chamber. This reverse blow-by breaks down the oil film on the cylinder walls and entrains oil particles in the gas flow during the downstroke of the piston. In this project a numerical model was developed that accurately describes the formation of aerosols in the ring pack by simulating the mechanisms by which oil globules are broken up, atomized, and entrained in a gas flowing through an orifice. The results of this numerical model are in good agreement with experimental values. Thus, this numerical model gives insight into the parameters that govern oil consumption. A discussion is also presented regarding the general applications of atomization and how past researchers have developed and advanced the theories of atomization.Included in this discussion is an introduction to past models of oil consumption and the conditions needed for aerosols to form within the ring-pack of a piston.

Disruption of gel phase lipid packing efficiency by sucralose studied with merocyanine 540.

PubMed

Barker, Morgan; Kennedy, Anthony

2017-04-01

Sucralose, an artificial sweetener, displays very different behavior towards membranes than its synthetic precursor sucrose. The impact of both sugars on model dipalmitoylphosphatidylcholine model membranes was investigated using absorbance and flourescence spectroscopy and the membrane probe merocyanine 540. This probe molecule is highly sensitive to changes in membrane packing, microviscosity and polarity. This work focuses on the impact of sugars on the outer leaflet of unilamellar dipalmitoyl phosphatidylcholine model membranes. The choice of lipid permits access to the gel phase at room temperature and incorporation of the dye after liposome formation allows us to examine the direct impact of the sugar on the outer leaflet while maximizing the response of the dye to changes in the bilayer. The results demonstrate that sucrose has no impact on the packing efficiency of lipids in unilamellar DPPC vesicles in the gel phase. Conversely sucralose decreases the packing efficiency of lipids in the gel phase and results in decreased microviscosity and increased membrane fluidity, which may be as a result of water disruption at the membrane water interface. Copyright © 2017 Elsevier B.V. All rights reserved.

Over-the-counter sales of out-of-state and counterfeit tax stamp cigarettes in New York City.

PubMed

Silver, Diana; Giorgio, Margaret M; Bae, Jin Yung; Jimenez, Geronimo; Macinko, James

2016-09-01

New York City (NYC) has strict minimum cigarette price and tax stamp laws, but evidence regarding the extent of evasion of such laws in over-the-counter sales is scarce. 830 packs were purchased at licensed tobacco retailers at 92 randomly selected neighbourhoods in NYC in spring and fall 2014, following the establishment of NYC's minimum price law. The χ(2) analyses of illegal tax stamps on pack, by retailer type and data collection period, are presented. Over 15% of packs purchased had out-of-state (4.5%) or counterfeit tax stamps (10.6%). Purchases resulted in at least one illegal pack obtained in 70% of neighbourhoods, largely from independent stores. In 21.5% of sampled neighbourhoods, it was possible to purchase an illegal pack each collection period. Enhanced enforcement of retail sales of cigarettes is needed to ensure the full benefit of existing tobacco control laws in NYC. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Type II PI4-kinases control Weibel-Palade body biogenesis and von Willebrand factor structure in human endothelial cells.

PubMed

Lopes da Silva, Mafalda; O'Connor, Marie N; Kriston-Vizi, Janos; White, Ian J; Al-Shawi, Raya; Simons, J Paul; Mössinger, Julia; Haucke, Volker; Cutler, Daniel F

2016-05-15

Weibel-Palade bodies (WPBs) are endothelial storage organelles that mediate the release of molecules involved in thrombosis, inflammation and angiogenesis, including the pro-thrombotic glycoprotein von Willebrand factor (VWF). Although many protein components required for WPB formation and function have been identified, the role of lipids is almost unknown. We examined two key phosphatidylinositol kinases that control phosphatidylinositol 4-phosphate levels at the trans-Golgi network, the site of WPB biogenesis. RNA interference of the type II phosphatidylinositol 4-kinases PI4KIIα and PI4KIIβ in primary human endothelial cells leads to formation of an increased proportion of short WPB with perturbed packing of VWF, as exemplified by increased exposure of antibody-binding sites. When stimulated with histamine, these cells release normal levels of VWF yet, under flow, form very few platelet-catching VWF strings. In PI4KIIα-deficient mice, immuno-microscopy revealed that VWF packaging is also perturbed and these mice exhibit increased blood loss after tail cut compared to controls. This is the first demonstration that lipid kinases can control the biosynthesis of VWF and the formation of WPBs that are capable of full haemostatic function. © 2016. Published by The Company of Biologists Ltd.

Modeling slug tests in unconfined aquifers with both oscillatory and overdamped responses, and with low-K and high-K skin effects

NASA Astrophysics Data System (ADS)

Thoma, M. J.; Malama, B.; Barrash, W.; Bohling, G.; Butler, J. J.

2009-12-01

We extend the models for slug tests developed by Hyder et al. (1994) and Butler and Zhan (2004) to obtain a single general model for slug tests in unconfined aquifers in partially penetrating wells with a near-well disturbed zone (skin). The full range of responses, oscillatory to overdamped, is considered since both types of responses are common in wells in unconsolidated coarse fluvial aquifers, and others. The general semi-analytical solution allows for skin and formation storage as well as anisotropy in skin and formation hydraulic conductivity (K). The water table is treated as a fixed head boundary so the solution is applicable for wells screened below the water table. The model is validated by comparison with other models and by matching field data from unconfined fluvial aquifers at sites in Nebraska (MSEA) and Idaho (BHRS). We examine the effects of varying skin K and skin thickness to simulate the impact of a near-well disturbed zone that is lower (damage) or higher (filter pack) K than the formation. Results indicate that, for a given set of measured behavior at an example test zone, minor progressive decreases in estimated formation K occur with increases in assumed skin K, and moderate increases in estimated formation K occur with decreases in assumed skin K. Major increases (orders of magnitude) in estimated formation K occur with increased thickness of low-K skin. The importance of incorporating a finite-thickness representation of the skin, rather than the conventional infinitely thin representation, is also addressed.

40 CFR 86.1870-12 - CO2 credits for qualifying full-size pickup trucks.

Code of Federal Regulations, 2013 CFR

2013-07-01

... broadcast battery pack voltage via an on-board diagnostics parameter ID channel. (1) Full size pickup trucks... conditioning leakage and/or efficiency credits as determined in §§ 86.1867 and 6.1868. Pickup trucks earning...

The impact of cigarette pack design, descriptors, and warning labels on risk perception in the U.S.

PubMed

Bansal-Travers, Maansi; Hammond, David; Smith, Philip; Cummings, K Michael

2011-06-01

In the U.S., limited evidence exists on the impact of colors and brand imagery used in cigarette pack design. This study examined the impact of pack design, product descriptors, and health warnings on risk perception and brand appeal. A cross-sectional mall-intercept study was conducted with 197 adult smokers and 200 nonsmokers in Buffalo NY from June to July 2009 (data analysis from July 2009 to December 2010). Participants were shown 12 sets of packs randomly; each set varied by a particular design feature (color, descriptor) or warning label style (text versus graphic, size, attribution, message framing). Packs were rated on criteria including risk perceptions, quit motivation, and purchase interest. Participants selected larger, pictorial, and loss-framed warning labels as more likely to attract attention, encourage thoughts about health risks, motivate quitting, and be most effective. Participants were more likely to select packs with lighter color shading and descriptors such as light, silver, and smooth as delivering less tar, smoother taste, and lower health risk, compared to darker-shaded or full-flavor packs. Additionally, participants were more likely to select the branded compared to plain white pack when asked which delivered the most tar, smoothest taste, was more attractive, appealed to youth aged <18 years, and contained cigarettes of better quality. The findings support larger, graphic health warnings that convey loss-framed messages as most effective in communicating health risks to U.S. adults. The results also indicate that color and product descriptors are associated with false beliefs about risks. Plain packaging may reduce many of the erroneous misperceptions of risk communicated through pack design features. Copyright © 2011 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

The Impact of Cigarette Pack Design, Descriptors, and Warning Labels on Risk Perception in the U.S

PubMed Central

Bansal-Travers, Maansi; Hammond, David; Smith, Philip; Cummings, K. Michael

2011-01-01

Background In the U.S., limited evidence exists on the impact of colors and brand imagery used in cigarette pack design. Purpose This study examined the impact of pack design, product descriptors, and health warnings on risk perception and brand appeal. Methods A cross-sectional mall-intercept study was conducted with 197 adult smokers and 200 nonsmokers in Buffalo, NY from June to July 2009 (data analysis from July 2009 to December 2010). Participants were shown 12 sets of packs randomly; each set varied by a particular design feature (color, descriptor) or warning label style (text vs graphic, size, attribution, message framing). Packs were rated on criteria including risk perceptions, quit motivation, and purchase interest. Results Participants selected larger, pictorial, and loss-framed warning labels as more likely to attract attention, encourage thoughts about health risks, motivate quitting, and most effective. Participants were more likely to select packs with lighter color shading and descriptors such as light, silver, and smooth as delivering less tar, smoother taste, and lower health risk, compared to darker-shaded or full flavor packs. Additionally, participants were more likely to select the branded compared to plain white pack when asked which delivered the most tar, smoothest taste, was more attractive, appealed to youth aged <18 years, and contained cigarettes of better quality. Conclusions The findings support larger, graphic health warnings that convey loss-framed messages as most effective in communicating health risks to U.S. adults. The results also indicate that color and product descriptors are associated with false beliefs about risks. Plain packaging may reduce many of the erroneous misperceptions of risk communicated through pack design features. PMID:21565661

Insight into the defects of cage-type silica mesoporous crystals with Fd3m symmetry: TEM observations and a new proposal of "polyhedron packing" for the crystals.

PubMed

Han, Lu; Sakamoto, Yasuhiro; Che, Shunai; Terasaki, Osamu

2009-01-01

Silica mesoporous crystals were synthesized by using a gemini cationic surfactant (C(18-3-1)) as the directing agent, carboxyethylsilanetriol sodium salt as the co-structure directing agent (CSDA), and varying amounts of HCl. By using transmission electron microscopy (TEM) we observed 1) a structural change from the close-packed structures of spherical micelles--face-centered cubic (Fm3m) and hexagonal close-packed (P6(3)/mmc)--to Fd3m structures with an increase of HCl and 2) a few structural defects in the crystals with Fd3m symmetry. The structure of a crystal with Fd3m symmetry is described as one of the tetrahedrally close-packed (tcp) structures consisting of 5(12) and 5(12)6(4) polyhedra. The observed TEM images of the structural defects were explained well through use of simulated TEM images by introducing new 13-15 polyhedra comprising 5(12)6(2), 5(12)6(3), 4(1)5(10)6(2), 4(2)5(8)6(5), and 4(1)5(10)6(4), which have been observed in bubbles by Matzke. The mesostructural changes and defect formation are discussed in terms of the hardness of micelles composed of surfactant/CSDA/silica species that have formed through a change of the interaction between the surfactant and CSDA, which causes the micelles to change from a regime of close-packing to one of minimum-area packing.

Application of Nanofiber-packed SPE for Determination of Urinary 1-Hydroxypyrene Level Using HPLC.

PubMed

Ifegwu, Okechukwu Clinton; Anyakora, Chimezie; Chigome, Samuel; Torto, Nelson

2014-01-01

It is always desirable to achieve maximum sample clean-up, extraction, and pre-concentration with the minimum possible organic solvent. The miniaturization of sample preparation devices was successfully demonstrated by packing 10 mg of 11 electrospun polymer nanofibers into pipette tip micro column and mini disc cartridges for efficient pre-concentration of 1-hydroxypyrene in urine samples. 1-hydroxypyrene is an extensively studied biomarker of the largest class of chemical carcinogens. Excretory 1-hydroxypyrene was monitored with HPLC/fluorescence detector. Important parameters influencing the percentage recovery such as fiber diameter, fiber packing amount, eluent, fiber packing format, eluent volume, surface area, porosity, and breakthrough parameters were thoroughly studied and optimized. Under optimized condition, there was a near perfect linearity of response in the range of 1-1000 μg/L with a coefficient of determination (r (2)) between 0.9992 and 0.9999 and precision (% RSD) ≤7.64% (n = 6) for all the analysis (10, 25, and 50 μg/L). The Limit of detection (LOD) was between 0.022 and 0.15 μg/L. When compared to the batch studies, both disc packed nanofiber sorbents and pipette tip packed sorbents exhibited evident dominance based on their efficiencies. The experimental results showed comparable absolute recoveries for the mini disc packed fibers (84% for Nylon 6) and micro columns (80% for Nylon 6), although the disc displayed slightly higher recoveries possibly due to the exposure of the analyte to a larger reacting surface. The results also showed highly comparative extraction efficiencies between the nanofibers and conventional C-18 SPE sorbent. Nevertheless, miniaturized SPE devices simplified sample preparation, reducing back pressure, time of the analysis with acceptable reliability, selectivity, detection levels, and environmental friendliness, hence promoting green chemistry.

Biolaminoid facies in a peritidal sabkha: Permian Platy Dolomite of northern Poland

NASA Astrophysics Data System (ADS)

Brehm, Ulrike; Gasiewicz, Andreij; Gerdes, Giesela; Krumbein, Wolfgang

The Platy Dolomite, a carbonate unit in the Zechstein Formation (Upper Permian) of the Leba Elevation, Poland, was deposited in a semi-closed or completely separated back-barrier sabkha environment. This arid, hypersaline zone is comparable to the recent Gavish Sabkha, Sinai. The processes which formed the modern Gavish Sabkha are similar to those responsible for the biolaminoid formation in the Platy Dolomite series. The deposition of this Platy Dolomite was mainly the result of microbial activity building extensive microbial mats. The Platy Dolomite is characterized by loosely packed microbial biolaminoids (a less significantly laminated build-up of biogenetic sediments) with horizontally or obliquely to vertically orientated filaments. Intermediary coated grains occur. Densely packed, flat laminated stromatolitic rocks, pure oolites, and bioclastic sedimentary strata are rarely intercalated with the biolaminoid beds. Laboratory and field investigations indicate that carbonate formation was induced by the chemoorganotrophic bacterial decay of cyanobacterial mats. Magnesium was bound and absorbed by organic matter and later liberated by anaerobic decay. Early diagenetic processes formed Mg2+- and Ca2+-enriched solutions in which carbonates precipitated biologically and chemically. A system of biogenic carbonate formation of the Platy Dolomite microbiolite series is proposed and supported by the results of microbiological laboratory studies.

STS-48 ESC Earth observation of ice pack, Antarctic Ice Shelf

NASA Technical Reports Server (NTRS)

1991-01-01

STS-48 Earth observation taken aboard Discovery, Orbiter Vehicle (OV) 103, is of the breakup of pack ice along the periphery of the Antarctic Ice Shelf. Strong offshore winds, probably associated with katabatic downdrafts from the interior of the continent, are seen peeling off the edges of the ice shelf into long filaments of sea ice, icebergs, bergy bits, and growlers to flow northward into the South Atlantic Ocean. These photos are used to study ocean wind, tide and current patterns. Similar views photographed during previous missions, when analyzed with these recent views may yield information about regional ice drift and breakup of ice packs. The image was captured using an electronic still camera (ESC), was stored on a removable hard disk or small optical disk, and was converted to a format suitable for downlink transmission. The ESC documentation was part of Development Test Objective (DTO) 648, Electronic Still Photography.

Thermodynamic properties of water in confined environments: a Monte Carlo study

NASA Astrophysics Data System (ADS)

Gladovic, Martin; Bren, Urban; Urbic, Tomaž

2018-05-01

Monte Carlo simulations of Mercedes-Benz water in a crowded environment were performed. The simulated systems are representative of both composite, porous or sintered materials and living cells with typical matrix packings. We studied the influence of overall temperature as well as the density and size of matrix particles on water density, particle distributions, hydrogen bond formation and thermodynamic quantities. Interestingly, temperature and space occupancy of matrix exhibit a similar effect on water properties following the competition between the kinetic and the potential energy of the system, whereby temperature increases the kinetic and matrix packing decreases the potential contribution. A novel thermodynamic decomposition approach was applied to gain insight into individual contributions of different types of inter-particle interactions. This decomposition proved to be useful and in good agreement with the total thermodynamic quantities especially at higher temperatures and matrix packings, where higher-order potential-energy mixing terms lose their importance.

H2S removal and bacterial structure along a full-scale biofilter bed packed with polyurethane foam in a landfill site.

PubMed

Li, Lin; Han, Yunping; Yan, Xu; Liu, Junxin

2013-11-01

Hydrogen sulfide accumulated under a cover film in a landfill site was treated for 7 months by a full-scale biofilter packed with polyurethane foam cubes. Sampling ports were set along the biofilter bed to investigate H2S removal and microbial characteristics in the biofilter. The H2S was removed effectively by the biofilter, and over 90% removal efficiency was achieved in steady state. Average elimination capacity of H2S was 2.21 g m(-3) h(-1) in lower part (LPB) and 0.41 g m(-3) h(-1) in upper part (UPB) of the biofilter. Most H2S was eliminated in LPB. H2S concentration varied along the polyurethane foam packed bed, the structure of the bacterial communities showed spatial variation in the biofilter, and H2S removal as well as products distribution changed accordingly. The introduction of odorants into the biofilter shifted the distribution of the existing microbial populations toward a specific culture that could metabolize the target odors. Copyright © 2013 Elsevier Ltd. All rights reserved.

Impact of smokeless tobacco packaging on perceptions and beliefs among youth, young adults, and adults in the U.S: findings from an internet-based cross-sectional survey

PubMed Central

2014-01-01

Background Research demonstrates that tobacco packaging elements (including health warning labels, descriptive characteristics, and corporate branding) are associated with knowledge of health risks and product appeal with cigarettes. Yet, little research has assessed this with smokeless tobacco (SLT) packaging. This study evaluates the association between three SLT packaging elements with knowledge of health risks and perceptions of novelty and appeal. Additionally, we assess how effects of these messages may differ across age groups, including youth (14-17 years), young adults (18-25 years), and older adults (26-65 years). Methods 1000 participants were administered a web-based survey in 2010 and shown three sets of SLT packs in random order, varied by descriptor (flavor descriptor vs. none), warning label format (graphic vs. text), and corporate branding (branded vs. plain packaging). Participants rated the packs compared with “no difference” on appeal, novelty, and risk perceptions associated with product use. Chi-square tests were used to test for significant differences in pack selections. Multinomial regression was employed to evaluate the association between effects of packaging elements and participant age. Results More respondents selected the pack with the graphic warning label as the pack to make them consider the health risks associated with SLT use, attract their attention, and be least attractive to a smoker. The product with the text warning label was the product someone their age would want to be seen using and would appeal to peers. The SLT pack with the flavor descriptor was not associated with health risks associated with product use. The pack with corporate branding was selected as more appealing, to attract attention, and one they would want to be seen using; the plain pack was less attractive to smokers. Youth and young adults were more likely to indicate that pack elements affected their perceptions of appeal and risk associated with SLT products. Conclusion These results suggest that SLT pack characteristics have a measurable effect on perceptions of health risk and product appeal. Future research should assess these findings in the context of harm reduction. Specifically, research is needed to determine whether pack elements on SLT products can effectively convey risk and harm. PMID:24433301

Impact of smokeless tobacco packaging on perceptions and beliefs among youth, young adults, and adults in the U.S: findings from an internet-based cross-sectional survey.

PubMed

Adkison, Sarah E; Bansal-Travers, Maansi; Smith, Danielle M; O'Connor, Richard J; Hyland, Andrew J

2014-01-17

Research demonstrates that tobacco packaging elements (including health warning labels, descriptive characteristics, and corporate branding) are associated with knowledge of health risks and product appeal with cigarettes. Yet, little research has assessed this with smokeless tobacco (SLT) packaging. This study evaluates the association between three SLT packaging elements with knowledge of health risks and perceptions of novelty and appeal. Additionally, we assess how effects of these messages may differ across age groups, including youth (14-17 years), young adults (18-25 years), and older adults (26-65 years). 1000 participants were administered a web-based survey in 2010 and shown three sets of SLT packs in random order, varied by descriptor (flavor descriptor vs. none), warning label format (graphic vs. text), and corporate branding (branded vs. plain packaging). Participants rated the packs compared with "no difference" on appeal, novelty, and risk perceptions associated with product use. Chi-square tests were used to test for significant differences in pack selections. Multinomial regression was employed to evaluate the association between effects of packaging elements and participant age. More respondents selected the pack with the graphic warning label as the pack to make them consider the health risks associated with SLT use, attract their attention, and be least attractive to a smoker. The product with the text warning label was the product someone their age would want to be seen using and would appeal to peers. The SLT pack with the flavor descriptor was not associated with health risks associated with product use. The pack with corporate branding was selected as more appealing, to attract attention, and one they would want to be seen using; the plain pack was less attractive to smokers. Youth and young adults were more likely to indicate that pack elements affected their perceptions of appeal and risk associated with SLT products. These results suggest that SLT pack characteristics have a measurable effect on perceptions of health risk and product appeal. Future research should assess these findings in the context of harm reduction. Specifically, research is needed to determine whether pack elements on SLT products can effectively convey risk and harm.

Appeals That Pack a Punch.

ERIC Educational Resources Information Center

Friesen, Patricia

1993-01-01

College alumni association mailings can be made more successful by targeting the audiences, delivering a strong proposition to readers, choosing a forceful format, and creating impressive copy. Efforts of the University of Minnesota, University of Iowa, and Southern Methodist University illustrate these principles. (MSE)

A systems approach to hemostasis: 4. How hemostatic thrombi limit the loss of plasma-borne molecules from the microvasculature

PubMed Central

Welsh, John D.; Muthard, Ryan W.; Stalker, Timothy J.; Taliaferro, Joshua P.; Diamond, Scott L.

2016-01-01

Previous studies have shown that hemostatic thrombi formed in response to penetrating injuries have a core of densely packed, fibrin-associated platelets overlaid by a shell of less-activated, loosely packed platelets. Here we asked, first, how the diverse elements of this structure combine to stem the loss of plasma-borne molecules and, second, whether antiplatelet agents and anticoagulants that perturb thrombus structure affect the re-establishment of a tight vascular seal. The studies combined high-resolution intravital microscopy with a photo-activatable fluorescent albumin marker to simultaneously track thrombus formation and protein transport following injuries to mouse cremaster muscle venules. The results show that protein loss persists after red cell loss has ceased. Blocking platelet deposition with an αIIbβ3 antagonist delays vessel sealing and increases extravascular protein accumulation, as does either inhibiting adenosine 5′-diphosphate (ADP) P2Y12 receptors or reducing integrin-dependent signaling and retraction. In contrast, sealing was unaffected by introducing hirudin to block fibrin accumulation or a Gi2α gain-of-function mutation to expand the thrombus shell. Collectively, these observations describe a novel approach for studying vessel sealing after injury in real time in vivo and show that (1) the core/shell architecture previously observed in arterioles also occurs in venules, (2) plasma leakage persists well beyond red cell escape and mature thrombus formation, (3) the most critical events for limiting plasma extravasation are the stable accumulation of platelets, ADP-dependent signaling, and the emergence of a densely packed core, not the accumulation of fibrin, and (4) drugs that affect platelet accumulation and packing can delay vessel sealing, permitting protein escape to continue. PMID:26738537

MODELING THE ELECTROLYTIC DECHLORINATION OF TRICHLOROETHYLENE IN A GRANULAR GRAPHITE-PACKED REACTOR

EPA Science Inventory

A comprehensive reactor model was developed for the electrolytic dechlorination of trichloroethylene (TCE) at a granular-graphite cathode. The reactor model describes the dynamic processes of TCE dechlorination and adsorption, and the formation and dechlorination of all the major...

Innovative approach for benzene degradation using hybrid surface/packed-bed discharge plasmas.

PubMed

Jiang, Nan; Lu, Na; Shang, Kefeng; Li, Jie; Wu, Yan

2013-09-03

An innovative plasma reactor, which generates hybrid surface/packed-bed discharge (HSPBD) plasmas, was employed for the degradation of benzene. The HSPBD reactor was found to display remarkably better benzene degradation, mineralization, and energy performance than surface or packed-bed discharge reactors alone. The degradation efficiency, CO2 selectivity, and energy yield in the HSPBD reactor were 21%, 11%, and 3.9 g kWh-1 higher, respectively, than in a surface discharge reactor and 30%, 21%, and 5.5 g kWh-1 higher, respectively, than in a packed-bed discharge reactor operated at 280 J L-1. Particularly, the benzene degradation in the HSPBD reactor exhibited an unambiguous synergistic enhancement rather than a simple additive effect using the surface discharge and packed-bed discharge reactors. Moreover, in the HSPBD reactor, the formation of byproducts, such as NO2, was suppressed, while O3 was promoted. The use of N2 as the carrier gas was found to be effective for benzene degradation because of the fast reaction rate of N2(A3∑u+) with benzene, and oxygen species derived from the dissociation of O2 were found to be significant in the mineralization process. Thus, the addition of O2 to N2 allows for efficient degradation of benzene, and the optimized amount of O2 was determined to be 3%.

Modeling of methanol decomposition on Pt/CeO2/ZrO2 catalyst in a packed bed microreactor

NASA Astrophysics Data System (ADS)

Pohar, Andrej; Belavič, Darko; Dolanc, Gregor; Hočevar, Stanko

2014-06-01

Methanol decomposition on Pt/CeO2/ZrO2 catalyst is studied inside a packed bed microreactor in the temperature range of 300-380 °C. The microreactor is fabricated using low-temperature co-fired ceramic (LTCC) technology, which is well suited for the production of relatively complex three-dimensional structures. It is packed with 2 wt% Pt-CeO2 catalyst, which is deposited onto ZrO2 spherical particles. A 1D mathematical model, which incorporates diffusion, convection and mass transfer through the boundary layer to the catalyst particles, as well as a 3D computational fluid dynamics model, are developed to describe the methanol decomposition process inside the packed bed. The microreactor exhibits reliable operation and no catalyst deactivation was observed during three months of experimentation. A comparison between the 1D mathematical model and the 3D model, considering the full 3D geometry of the microreactor is made and the differences between the models are identified and evaluated.

Novel amelogenin-releasing hydrogel for remineralization of enamel artificial caries

PubMed Central

Fan, Yuwei; Wen, Zezhang T; Liao, Sumei; Lallier, Thomas; Hagan, Joseph L; Twomley, Jefferson T; Zhang, Jian-Feng; Sun, Zhi; Xu, Xiaoming

2013-01-01

Recently, the use of recombinant full-length amelogenin protein in combination with fluoride has shown promising results in the formation of densely packed enamel-like structures. In this study, amelogenin (rP172)-releasing hydrogels containing calcium, phosphate, and fluoride were investigated for remineralization efficacy using in vitro early enamel caries models. The hydrogels were applied to artificial caries lesions on extracted human third molars, and the remineralization efficacy was tested in different models: static gel remineralization in the presence of artificial saliva, pH cyclic treatment at pH 5.4 acetic buffer and pH 7.3 gel remineralization, and treatment with multispecies oral biofilms grown in a continuous flowing constant-depth film fermenter. The surface microhardness of remineralized enamel increased significantly when amelogenin was released from hydrogel. No cytotoxicity was observed when periodontal ligament cells were cultured with the mineralized hydrogels. PMID:23338820

A crystal plasticity model for slip in hexagonal close packed metals based on discrete dislocation simulations

NASA Astrophysics Data System (ADS)

Messner, Mark C.; Rhee, Moono; Arsenlis, Athanasios; Barton, Nathan R.

2017-06-01

This work develops a method for calibrating a crystal plasticity model to the results of discrete dislocation (DD) simulations. The crystal model explicitly represents junction formation and annihilation mechanisms and applies these mechanisms to describe hardening in hexagonal close packed metals. The model treats these dislocation mechanisms separately from elastic interactions among populations of dislocations, which the model represents through a conventional strength-interaction matrix. This split between elastic interactions and junction formation mechanisms more accurately reproduces the DD data and results in a multi-scale model that better represents the lower scale physics. The fitting procedure employs concepts of machine learning—feature selection by regularized regression and cross-validation—to develop a robust, physically accurate crystal model. The work also presents a method for ensuring the final, calibrated crystal model respects the physical symmetries of the crystal system. Calibrating the crystal model requires fitting two linear operators: one describing elastic dislocation interactions and another describing junction formation and annihilation dislocation reactions. The structure of these operators in the final, calibrated model reflect the crystal symmetry and slip system geometry of the DD simulations.

Self-assembly of silica nanoparticles by tuning substrate-adsorbate interaction

NASA Astrophysics Data System (ADS)

Utsav, Khanna, Sakshum; Mukhopadhayay, Indrajit; Banerjee, Rupak

2018-05-01

We report on self-assembled nanodisc formations of silica nanoparticles on a surface modified silicon substrate using modified Langmuir-Schafer deposition technique (stamping). The size, inter-particle separation as well as the packing of the silica nanoparticles within the nanodiscs formed spontaneously can be tuned by the surface pressure applied on the water surface. We obtain self-assembled nanodiscs of silica nanoparticle arranged in a hexagonal symmetry. We also observe that by varying the surface pressure of deposition at the water-molecule-air interface we obtain such 2D disc-shaped structure with varying sizes and a packing ratio of the silica nanoparticle.

Warpage analysis in injection moulding process

NASA Astrophysics Data System (ADS)

Hidayah, M. H. N.; Shayfull, Z.; Nasir, S. M.; Fathullah, M.; Hazwan, M. H. M.

2017-09-01

This study was concentrated on the effects of process parameters in plastic injection moulding process towards warpage problem by using Autodesk Moldflow Insight (AMI) software for the simulation. In this study, plastic dispenser of dental floss has been analysed with thermoplastic material of Polypropylene (PP) used as the moulded material and details properties of 80 Tonne Nessei NEX 1000 injection moulding machine also has been used in this study. The variable parameters of the process are packing pressure, packing time, melt temperature and cooling time. Minimization of warpage obtained from the optimization and analysis data from the Design Expert software. Integration of Response Surface Methodology (RSM), Center Composite Design (CCD) with polynomial models that has been obtained from Design of Experiment (DOE) is the method used in this study. The results show that packing pressure is the main factor that will contribute to the formation of warpage in x-axis and y-axis. While in z-axis, the main factor is melt temperature and packing time is the less significant among the four parameters in x, y and z-axes. From optimal processing parameter, the value of warpage in x, y and z-axis have been optimised by 21.60%, 26.45% and 24.53%, respectively.

Clot contraction: compression of erythrocytes into tightly packed polyhedra and redistribution of platelets and fibrin

PubMed Central

Cines, Douglas B.; Lebedeva, Tatiana; Nagaswami, Chandrasekaran; Hayes, Vincent; Massefski, Walter; Litvinov, Rustem I.; Rauova, Lubica; Lowery, Thomas J.

2014-01-01

Contraction of blood clots is necessary for hemostasis and wound healing and to restore flow past obstructive thrombi, but little is known about the structure of contracted clots or the role of erythrocytes in contraction. We found that contracted blood clots develop a remarkable structure, with a meshwork of fibrin and platelet aggregates on the exterior of the clot and a close-packed, tessellated array of compressed polyhedral erythrocytes within. The same results were obtained after initiation of clotting with various activators and also with clots from reconstituted human blood and mouse blood. Such close-packed arrays of polyhedral erythrocytes, or polyhedrocytes, were also observed in human arterial thrombi taken from patients. The mechanical nature of this shape change was confirmed by polyhedrocyte formation from the forces of centrifugation of blood without clotting. Platelets (with their cytoskeletal motility proteins) and fibrin(ogen) (as the substrate bridging platelets for contraction) are required to generate the forces necessary to segregate platelets/fibrin from erythrocytes and to compress erythrocytes into a tightly packed array. These results demonstrate how contracted clots form an impermeable barrier important for hemostasis and wound healing and help explain how fibrinolysis is greatly retarded as clots contract. PMID:24335500

Time-Dependent Solid State Polymorphism of a Series of Donor-Acceptor Dyads

PubMed Central

Peebles, Cameron; Alvey, Paul M.; Lynch, Vincent; Iverson, Brent L.

2014-01-01

In order to exploit the use of favorable electrostatic interactions between aromatic units in directing the assembly of donor-acceptor (D-A) dyads, the present work examines the ability of conjugated aromatic D-A dyads with symmetric side chains to exhibit solid-state polymorphism as a function of time during the solid formation process. Four such dyads were synthesized and their packing in the solid-state from either slower (10-20 days) or faster (1-2 days) evaporation from solvent was investigated using single crystal X-ray analysis and powder X-ray diffraction. Two of the dyads exhibited tail-to-tail (A-A) packing upon slower evaporation from solvent and head-to-tail (D-A) packing upon faster evaporation from solvent. A combination of single crystal analysis and XRD patterns were used to create models wherein a packing model for the other two dyads is proposed. Our findings suggest that while side chain interactions in asymmetric aromatic dyads can play an important role in enforcing segregated D-A dyad assembly, slowly evaporating symmetrically substituted aromatic dyads allows for favorable electrostatic interactions between the aromatic moieties to facilitate the organization of the dyads in the solid-state. PMID:24678269

Novel thermal management system design methodology for power lithium-ion battery

NASA Astrophysics Data System (ADS)

Nieto, Nerea; Díaz, Luis; Gastelurrutia, Jon; Blanco, Francisco; Ramos, Juan Carlos; Rivas, Alejandro

2014-12-01

Battery packs conformed by large format lithium-ion cells are increasingly being adopted in hybrid and pure electric vehicles in order to use the energy more efficiently and for a better environmental performance. Safety and cycle life are two of the main concerns regarding this technology, which are closely related to the cell's operating behavior and temperature asymmetries in the system. Therefore, the temperature of the cells in battery packs needs to be controlled by thermal management systems (TMSs). In the present paper an improved design methodology for developing TMSs is proposed. This methodology involves the development of different mathematical models for heat generation, transmission, and dissipation and their coupling and integration in the battery pack product design methodology in order to improve the overall safety and performance. The methodology is validated by comparing simulation results with laboratory measurements on a single module of the battery pack designed at IK4-IKERLAN for a traction application. The maximum difference between model predictions and experimental temperature data is 2 °C. The models developed have shown potential for use in battery thermal management studies for EV/HEV applications since they allow for scalability with accuracy and reasonable simulation time.

Electron core ionization in compressed alkali metal cesium

NASA Astrophysics Data System (ADS)

Degtyareva, V. F.

2018-01-01

Elements of groups I and II in the periodic table have valence electrons of s-type and are usually considered as simple metals. Crystal structures of these elements at ambient pressure are close-packed and high-symmetry of bcc and fcc-types, defined by electrostatic (Madelung) energy. Diverse structures were found under high pressure with decrease of the coordination number, packing fraction and symmetry. Formation of complex structures can be understood within the model of Fermi sphere-Brillouin zone interactions and supported by Hume-Rothery arguments. With the volume decrease there is a gain of band structure energy accompanied by a formation of many-faced Brillouin zone polyhedra. Under compression to less than a half of the initial volume the interatomic distances become close to or smaller than the ionic radius which should lead to the electron core ionization. At strong compression it is necessary to assume that for alkali metals the valence electron band overlaps with the upper core electrons, which increases the valence electron count under compression.

Rheological Enhancement of Pork Myofibrillar Protein-Lipid Emulsion Composite Gels via Glucose Oxidase Oxidation/Transglutaminase Cross-Linking Pathway.

PubMed

Wang, Xu; Xiong, Youling L; Sato, Hiroaki

2017-09-27

Porcine myofibrillar protein (MP) was modified with glucose oxidase (GluOx)-iron that produces hydroxyl radicals then subjected to microbial transglutaminase (TGase) cross-linking in 0.6 M NaCl at 4 °C. The resulting aggregation and gel formation of MP were examined. The GluOx-mediated oxidation promoted the formation of both soluble and insoluble protein aggregates via disulfide bonds and occlusions of hydrophobic groups. The subsequent TGase treatment converted protein aggregates into highly cross-linked polymers. MP-lipid emulsion composite gels formed with such polymers exhibited markedly enhanced gelling capacity: up to 4.4-fold increases in gel firmness and 3.5-fold increases in gel elasticity over nontreated protein. Microstructural examination showed small oil droplets dispersed in a densely packed gel matrix when MP was oxidatively modified, and the TGase treatment further contributed to such packing. The enzymatic GluOx oxidation/TGase treatment shows promise to improve the textural properties of emulsified meat products.

Wind Tunnel Experiments: Influence of Erosion and Deposition on Wind-Packing of New Snow

NASA Astrophysics Data System (ADS)

Sommer, C.; Fierz, C. G.; Lehning, M.

2017-12-01

We observed the formation of wind crusts in wind tunnel experiments. A SnowMicroPen was used to measure the hardness profile of the snow and a Microsoft Kinect provided distributed snow depth data. Earlier experiments showed that no crust forms without saltation and that the dynamics of erosion and deposition may be a key factor to explain wind-packing. The Kinect data could be used to quantify spatial erosion and deposition patterns and the combination with the SnowMicroPen data allowed to study the effect of erosion and deposition on wind-hardening. We found that erosion had no hardening effect on fresh snow and that deposition is a necessary but not sufficient condition for wind crust formation. Deposited snow was only hardened in wind-exposed areas. The Kinect data was used to calculate the wind-exposure parameter Sx. We observed no significant hardening for Sx>0.25. The variability of resulting wind crust hardnesses at Sx<0.25 was still large, however.

Is incest common in gray wolf packs?

USGS Publications Warehouse

Smith, Deborah E; Meier, Thomas J.; Geffen, Eli; Mech, L. David; Burch, John W.; Adams, Layne G.; Wayne, Robert K.

1997-01-01

Wolf packs generally consist of a breeding pair and their maturing offspring that help provision and protect pack young. Because the reproductive tenure in wolves is often short, reproductively mature offspring might replace their parents, resulting in sibling or parent-offspring matings. To determine the extent of incestuous pairings, we measured relatedness based on variability in 20 microsatellite loci of mated pairs, parent-offspring pairs, and siblings in two populations of gray wolves. Our 16 sampled mated pairs had values of relatedness not overlapping those of known parent-offspring or sibling dyads, which is consistent with their being unrelated or distantly related. These results suggest that full siblings or a parent and its offspring rarely mate and that incest avoidance is an important constraint on gray wolf behavioral ecology.

Arctic sea ice melt leads to atmospheric new particle formation.

PubMed

Dall Osto, M; Beddows, D C S; Tunved, P; Krejci, R; Ström, J; Hansson, H-C; Yoon, Y J; Park, Ki-Tae; Becagli, S; Udisti, R; Onasch, T; O Dowd, C D; Simó, R; Harrison, Roy M

2017-06-12

Atmospheric new particle formation (NPF) and growth significantly influences climate by supplying new seeds for cloud condensation and brightness. Currently, there is a lack of understanding of whether and how marine biota emissions affect aerosol-cloud-climate interactions in the Arctic. Here, the aerosol population was categorised via cluster analysis of aerosol size distributions taken at Mt Zeppelin (Svalbard) during a 11 year record. The daily temporal occurrence of NPF events likely caused by nucleation in the polar marine boundary layer was quantified annually as 18%, with a peak of 51% during summer months. Air mass trajectory analysis and atmospheric nitrogen and sulphur tracers link these frequent nucleation events to biogenic precursors released by open water and melting sea ice regions. The occurrence of such events across a full decade was anti-correlated with sea ice extent. New particles originating from open water and open pack ice increased the cloud condensation nuclei concentration background by at least ca. 20%, supporting a marine biosphere-climate link through sea ice melt and low altitude clouds that may have contributed to accelerate Arctic warming. Our results prompt a better representation of biogenic aerosol sources in Arctic climate models.

Subcutaneous packing in royal Egyptian mummies dated from 18th to 20th dynasties.

PubMed

Saleem, Sahar N; Hawass, Zahi

2015-01-01

It has been widely disseminated in the literature that subcutaneous packing, as part of mummification, was not usually done until the 21st dynasty. We aimed to study by computed tomography (CT) if subcutaneous packing was part of mummification of royal Egyptians dated to 18th to 20th dynasties. We analyzed the 2- and 3-dimensional CT images of 13 royal mummies dated to circa 1550 to 1153 BC for presence of subcutaneous embalming materials. Among the studied mummies were Amenhotep III, Tutankhamun, Seti I, and Ramesses II. We reported the CT characters of any detected subcutaneous embalming materials and noted their impact on the morphology of the involved body part. We correlated the CT findings with the archeological literature. Computed tomographic images showed subcutaneous packing in 12 (92.3%) mummies; whereas the mummy that was previously known as "Thutmose I" showed no such evidence. Subcutaneous packing involved the faces (n = 11), necks (n = 4), torsos (n = 5), and/or extremities (n = 4) of the mummies. Subcutaneous filling materials showed variation in homogeneity and CT densities and they were likely composed of resin, bits of linen with resin, or other substances. Subcutaneous packing procedure succeeded in providing uniform full contour of the involved body regions without causing significant tissue damages. Subcutaneous packing procedure was used as part of mummification of royal Ancient Egyptians dated to 18th to 20th dynasties earlier than what was believed in archaeology. The Ancient Egyptian embalmers must have been skilled in dissection and possessed surgical tools that enabled them to perform this fine procedure.

Coprocessed nuclear fuels containing (U, Pu) values as oxides, carbides or carbonitrides

DOEpatents

Lloyd, M.H.

1981-01-09

Method for direct coprocessing of nuclear fuels derived from a product stream of fuels reprocessing facility containing uranium, plutonium, and fission product values comprising nitrate stabilization of said stream vacuum concentration to remove water and nitrates, neutralization to form an acid deficient feed solution for the internal gelation mode of sol-gel technology, green spherule formation, recovery and treatment for loading into a fuel element by vibra packed or pellet formation technologies.

Coprocessed nuclear fuels containing (U, Pu) values as oxides, carbides or carbonitrides

DOEpatents

Lloyd, Milton H.

1983-01-01

Method for direct coprocessing of nuclear fuels derived from a product stream of a fuels reprocessing facility containing uranium, plutonium, and fission product values comprising nitrate stabilization of said stream vacuum concentration to remove water and nitrates, neutralization to form an acid deficient feed solution for the internal gelation mode of sol-gel technology, green spherule formation, recovery and treatment for loading into a fuel element by vibra packed or pellet formation technologies.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuz'mina, L. G., E-mail: kuzmina@igic.ras.ru; Kucherepa, N. S.; Rodnikova, M. N.

The molecular and crystal structures of two p-alkoxybenzylidene)-p'-toluidines C{sub 2}H{sub 5}O-C{sub 6}H{sub 4}-CH=N-C{sub 6}H{sub 4}-CH{sub 3} (1) and C{sub 4}H{sub 9}O-C{sub 6}H{sub 4}-CH=N-C{sub 6}H{sub 4}-CH{sub 3} (2) are determined by X-ray diffraction. Crystals 1 and 2 contain four and two crystallographically independent molecules, respectively. In 1, the geometry of the independent molecules is almost identical. In 2, the independent molecules differ in the conformation of the alkyl chain, which is disordered in one of them. An analysis of the crystal packing of 2 reveals the alternation of spacious layers formed by loosely packed aliphatic fragments of molecules and layers ofmore » closely packed aromatic fragments, which ensures the formation of the mesogenic phase in the course of melting of crystals 2. In crystal 1, loose aliphatic layers are absent.« less

A new biodegradable sisal fiber-starch packing composite with nest structure.

PubMed

Xie, Qi; Li, Fangyi; Li, Jianfeng; Wang, Liming; Li, Yanle; Zhang, Chuanwei; Xu, Jie; Chen, Shuai

2018-06-01

A new completely biodegradable sisal fiber-starch packing composite was proposed. The effects of fiber content and alkaline treatment on the cushioning property of the composites were studied from energy absorption efficiency, cellular microstructure and compatibility between fiber and starch. With increasing fiber content, the nest structure of composites becomes dense first and then loosens, resulting in initial enhancement and subsequent weakening of the cushioning property of the composites. The composite with 4:13 mass ratio of fiber and thermoplastic starch (TPS) exhibit the optimal cushioning property. Alkaline treatment increases the compatibility between sisal fiber and TPS, promotes the formation of dense nest structure, thereby enhances the cushioning property of the composites. After biodegradability tests for 28 days, the weight loss of the composites was 62.36%. It's found that the composites are a promising replacement for expandable polystyrene (EPS) as packing material, especially under large compression load (0.7-6 MPa). Copyright © 2018 Elsevier Ltd. All rights reserved.

Biotransformation of ferulic acid to vanillin in the packed bed-stirred fermentors

PubMed Central

Yan, Lei; Chen, Peng; Zhang, Shuang; Li, Suyue; Yan, Xiaojuan; Wang, Ningbo; Liang, Ning; Li, Hongyu

2016-01-01

We performed the biotransformation of ferulic acid to vanillin using Bacillus subtilis (B. subtilis) in the stirring packed-bed reactors filled with carbon fiber textiles (CFT). Scanning electron microscope (SEM), HPLC, qRT-PCR and ATP assay indicated that vanillin biotransformation is tightly related to cell growth, cellar activity and the extent of biofilm formation. The biotransformation was affected by hydraulic retention time (HRT), temperature, initial pH, stirring speed and ferulic acid concentration, and the maximum vanillin production was obtained at 20 h, 35 °C, 9.0, 200 rpm, 1.5 g/L, respectively. Repeated batch biotransformation performed under this optimized condition showed that the maximum productivity (0.047 g/L/h) and molar yield (60.43%) achieved in immobilized cell system were 1.84 and 3.61 folds higher than those achieved in free cell system. Therefore, the stirring reactor packed with CFT carrier biofilm formed by B. subtilis represented a valid biocatalytic system for the production of vanillin. PMID:27708366

Crack-resistant Al2O3-SiO2 glasses.

PubMed

Rosales-Sosa, Gustavo A; Masuno, Atsunobu; Higo, Yuji; Inoue, Hiroyuki

2016-04-07

Obtaining "hard" and "crack-resistant" glasses have always been of great important in glass science and glass technology. However, in most commercial glasses both properties are not compatible. In this work, colorless and transparent xAl2O3-(100-x)SiO2 glasses (30 ≤ x ≤ 60) were fabricated by the aerodynamic levitation technique. The elastic moduli and Vickers hardness monotonically increased with an increase in the atomic packing density as the Al2O3 content increased. Although a higher atomic packing density generally enhances crack formation in conventional oxide glasses, the indentation cracking resistance increased by approximately seven times with an increase in atomic packing density in binary Al2O3-SiO2 glasses. In particular, the composition of 60Al2O3 • 40SiO2 glass, which is identical to that of mullite, has extraordinary high cracking resistance with high elastic moduli and Vickers hardness. The results indicate that there exist aluminosilicate compositions that can produce hard and damage-tolerant glasses.

Self-assembly of (perfluoroalkyl)alkanes on a substrate surface from solutions in supercritical carbon dioxide.

PubMed

Gallyamov, Marat O; Mourran, Ahmed; Tartsch, Bernd; Vinokur, Rostislav A; Nikitin, Lev N; Khokhlov, Alexei R; Schaumburg, Kjeld; Möller, Martin

2006-06-14

Toroidal self-assembled structures of perfluorododecylnonadecane and perfluorotetradecyloctadecane have been deposited on mica and highly oriented pyrolytic graphite surfaces by exposure of the substrates to solutions of the (pefluoroalkyl)alkanes in supercritical carbon dioxide. Scanning force microscopy (SFM) images have displayed a high degree of regularity of these self-assembled nanoobjects regarding size, shape, and packing in a monolayer. Analysis of SFM images allowed us to estimate that each toroidal domain has an outer diameter of about 50 nm and consists of several thousands of molecules. We propose a simple model explaining the clustering of the molecules to objects with a finite size. The model based on the close-packing principles predicts formation of toroids, whose size is determined by the molecular geometry. Here, we consider the amphiphilic nature of the (perfluoroalkyl)alkane molecules in combination with incommensurable packing parameters of the alkyl- and the perfluoralkyl-segments to be a key factor for such a self-assembly.

Evaluation of diminished microbial contamination in handling of a novel daily disposable flat pack contact lens.

PubMed

Nomachi, Miya; Sakanishi, Kotaro; Ichijima, Hideji; Cavanagh, H Dwight

2013-05-01

To evaluate the efficacy of a novel daily disposable (DD) flat package in regard to microbial contamination on the anterior and posterior surfaces of a contact lens (CL) during handling of the lens for insertion. Four kinds of commercially available general blister-packed daily disposable contact lenses (DD CLs) as controls and a novel Magic 1-day Menicon Flat Pack as a test lens were used for this in vitro study. Lenses were removed from their packages using fingers coated with fluorescein 3 to 5 μm beads or an approximately 7×10(2) to 2×10(3) colony-forming unit (CFU)/mL Staphylococcus aureus suspension. The transfer of fluorescein beads to the surface of the lenses was then observed by fluorescence microscopy. Microbial contamination on the lenses was observed by light microscopy after a 2-day incubation period; and, the number of colonies isolated from the contaminated lenses was determined after 4 days of incubation. The number of fluorescein beads on the Magic lens was significantly less (p<0.05) than that of the general blister-packed control lenses. Adherence of microbial colonies was observed on both inner and outer surfaces of general blister-packed lenses, whereas no colony formation was found on the inner surface of the Magic lens, and the lowest bacterial adherence was observed for the Magic lens. The data demonstrated that placement of the Magic DD lens onto the eye is accompanied by diminished microbial contamination compared with general blister-packed DD CLs. Eye care professionals; however, should instruct patients to comply with intended use of DD CLs to prevent CL-associated microbial keratitis. In all cases, hand washing is mandated prelens insertion.

Exposure to airborne asbestos during removal and installation of gaskets and packings: a review of published and unpublished studies.

PubMed

Madl, Amy K; Clark, Katherine; Paustenbach, Dennis J

2007-01-01

In recent years, questions have been raised about the health risks to persons who have been occupationally exposed to asbestos-containing gaskets and packing materials used in pipes, valves, and machinery (pumps, autos, etc.). Up until the late 1970s, these materials were widely used throughout industrial and maritime operations, refineries, chemical plants, naval ships, and energy plants. Seven simulation studies and four work-site industrial hygiene studies of industrial and maritime settings involving the collection of more than 300 air samples were evaluated to determine the likely airborne fiber concentrations to which a worker may have been exposed while working with encapsulated asbestos-containing gaskets and packing materials. Each study was evaluated for the representativeness of work practices, analytical methods, sample size, and potential for asbestos contamination (e.g., insulation on valves or pipes used in the study). Specific activities evaluated included the removal and installation of gaskets and packings, flange cleaning, and gasket formation. In all but one of the studies relating to the replacement of gaskets and packing using hand-held tools, the short-term average exposures were less than the current 30-min OSHA excursion limit of 1 fiber per cubic centimeter (f/cc) and all of the long-term average exposures were less than the current 8-h permissible exposure limit time-weighted average (PEL-TWA) of 0.1 f/cc. The weight of evidence indicates that the use of hand tools and hand-operated power tools to remove or install gaskets or packing as performed by pipefitters or other tradesmen in nearly all plausible situations would not have produced airborne concentrations in excess of contemporaneous regulatory levels.

Consumer preferences for front-of-pack calories labelling.

PubMed

van Kleef, Ellen; van Trijp, Hans; Paeps, Frederic; Fernández-Celemín, Laura

2008-02-01

In light of the emerging obesity pandemic, front-of-pack calories labels may be an important tool to assist consumers in making informed healthier food choices. However, there is little prior research to guide key decisions on whether caloric content should be expressed in absolute terms or relative to recommended daily intake, whether it should be expressed in per serving or per 100 g and whether the information should be further brought alive for consumers in terms of what the extra calorie intake implies in relation to activity levels. The present study aimed at providing more insight into consumers' appreciation of front-of-pack labelling of caloric content of food products and their specific preferences for alternative execution formats for such information in Europe. For this purpose, eight executions of front-of-pack calorie flags were designed and their appeal and information value were extensively discussed with consumers through qualitative research in four different countries (Germany, The Netherlands, France and the UK). The results show that calories are well-understood and that participants were generally positive about front-of-pack flags, particularly when flags are uniform across products. The most liked flags are the simpler flags depicting only the number of calories per serving or per 100 g, while more complex flags including references to daily needs or exercise and the flag including a phrase referring to balanced lifestyle were least preferred. Some relevant differences between countries were observed. Although participants seem to be familiar with the notion of calories, they do not seem to fully understand how to apply them. From the results, managerial implications for the design and implementation of front-of-pack calorie labelling as well as important directions for future research are discussed.

Consumer preferences for front-of-pack calories labelling

PubMed Central

van Kleef, Ellen; van Trijp, Hans; Paeps, Frederic; Fernández-Celemín, Laura

2008-01-01

Objective In light of the emerging obesity pandemic, front-of-pack calories labels may be an important tool to assist consumers in making informed healthier food choices. However, there is little prior research to guide key decisions on whether caloric content should be expressed in absolute terms or relative to recommended daily intake, whether it should be expressed in per serving or per 100 g and whether the information should be further brought alive for consumers in terms of what the extra calorie intake implies in relation to activity levels. The present study aimed at providing more insight into consumers’ appreciation of front-of-pack labelling of caloric content of food products and their specific preferences for alternative execution formats for such information in Europe. Design For this purpose, eight executions of front-of-pack calorie flags were designed and their appeal and information value were extensively discussed with consumers through qualitative research in four different countries (Germany, The Netherlands, France and the UK). Results The results show that calories are well-understood and that participants were generally positive about front-of-pack flags, particularly when flags are uniform across products. The most liked flags are the simpler flags depicting only the number of calories per serving or per 100 g, while more complex flags including references to daily needs or exercise and the flag including a phrase referring to balanced lifestyle were least preferred. Some relevant differences between countries were observed. Although participants seem to be familiar with the notion of calories, they do not seem to fully understand how to apply them. Conclusion From the results, managerial implications for the design and implementation of front-of-pack calorie labelling as well as important directions for future research are discussed. PMID:17601362

Hydraulic fracture conductivity: effects of rod-shaped proppant from lattice-Boltzmann simulations and lab tests

NASA Astrophysics Data System (ADS)

Osiptsov, Andrei A.

2017-06-01

The goal of this study is to evaluate the conductivity of random close packings of non-spherical, rod-shaped proppant particles under the closure stress using numerical simulation and lab tests, with application to the conductivity of hydraulic fractures created in subterranean formation to stimulate production from oil and gas reservoirs. Numerical simulations of a steady viscous flow through proppant packs are carried out using the lattice Boltzmann method for the Darcy flow regime. The particle packings were generated numerically using the sequential deposition method. The simulations are conducted for packings of spheres, ellipsoids, cylinders, and mixtures of spheres with cylinders at various volumetric concentrations. It is demonstrated that cylinders provide the highest permeability among the proppants studied. The dependence of the nondimensional permeability (scaled by the equivalent particle radius squared) on porosity obtained numerically is well approximated by the power-law function: K /Rv2 = 0.204ϕ4.58 in a wide range of porosity: 0.3 ≤ ϕ ≤ 0.7. Lattice-Boltzmann simulations are cross-verified against finite-volume simulations using Navier-Stokes equations for inertial flow regime. Correlations for the normalized beta-factor as a function of porosity and normalized permeability are presented as well. These formulae are in a good agreement with the experimental measurements (including packings of rod-shaped particles) and existing laboratory data, available in the porosity range 0.3 ≤ ϕ ≤ 0.5. Comparison with correlations by other authors is also given.

Supramolecular Packing Controls H 2 Photocatalysis in Chromophore Amphiphile Hydrogels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weingarten, Adam S.; Kazantsev, Roman V.; Palmer, Liam C.

2015-11-21

Light harvesting supramolecular assemblies are potentially useful structures as components of solar-to-fuel conversion materials. The development of these functional constructs requires an understanding of optimal packing modes for chromophores. We investigated here assembly in water and the photocatalytic function of perylene monoimide chromophore amphiphiles with different alkyl linker lengths separating their hydrophobic core and the hydrophilic carboxylate headgroup. We found that these chromophore amphiphiles (CAs) self-assemble into charged nanostructures of increasing aspect ratio as the linker length is increased. The addition of salt to screen the charged nanostructures induced the formation of hydrogels and led to internal crystallization within somemore » of the nanostructures. For linker lengths up to seven methylenes, the CAs were found to pack into 2D crystalline unit cells within ribbon-shaped nanostructures, whereas the nine methylene CAs assembled into long nanofibers without crystalline molecular packing. At the same time, the different molecular packing arrangements after charge screening led to different absorbance spectra, despite the identical electronic properties of all PMI amphiphiles. While the crystalline CAs formed electronically coupled H-aggregates, only CAs with intermediate linker lengths showed evidence of high intermolecular orbital overlap. Photocatalytic hydrogen production using a nickel-based catalyst was observed in all hydrogels, with the highest turnovers observed for CA gels having intermediate linker lengths. We conclude that the improved photocatalytic performance of the hydrogels formed by supramolecular assemblies of the intermediate linker CA molecules likely arises from improved exciton splitting efficiencies due to their higher orbital overlap.« less

Unit: Rocks from Sediments, Inspection Pack, National Trial Print.

ERIC Educational Resources Information Center

Australian Science Education Project, Toorak, Victoria.

Four compulsory introductory activities, involving learning to use a stream tray, observing the relationship between water speed and entraining, transporting and depositing sediments, studying the formation of sedimentary rocks, and examining several types of sedimentary rocks, are completed by all students using the unit prepared for Australian…

Characterisation of RPLC columns packed with porous sub-2 microm particles.

PubMed

Petersson, Patrik; Euerby, Melvin R

2007-08-01

Eight commercially available sub-2 microm octadecyl silane columns (C18 columns) have been characterised by the Tanaka protocol. The columns can be grouped into two groups that display large differences in selectivity and peak shape due to differences in hydrophobicity, degree of surface coverage and silanol activity. Measurements of particle size distributions were made using automated microscopy and electrical sensing zone measurements. Only a weak correlation could be found between efficiency and particle size. Large differences in column backpressure were observed. These differences are not related to particle size distribution. A more likely explanation is differences in packing density. In order to take full advantage of 100-150 mm columns packed with sub-2 microm particles, it is often necessary to employ not only an elevated pressure but also an elevated temperature. A comparison between columns packed with sub-2, 3 and 5 microm versions of the same packing indicates potential method transferability problems for several of the columns due to selectivity differences. Currently, the best alternative for fast high-resolution LC is the use of sub-2 microm particles in combination with elevated pressure and temperature. However, as shown in this study additional efforts are needed to improve transferability as well as column performance.

Does every US smoker bear the same cigarette tax?

PubMed Central

Xu, Xin; Malarcher, Ann; O’Halloran, Alissa; Kruger, Judy

2015-01-01

Aims To evaluate state cigarette excise tax pass-through rates for selected price-minimizing strategies. Design Multivariate regression analysis of current smokers from a stratified, national, dual-frame telephone survey. Setting United States. Participants A total of 16 542 adult current smokers aged 18 years or older. Measurements Cigarette per pack prices paid with and without coupons were obtained for pack versus carton purchase, use of generic brands versus premium brands, and purchase from Indian reservations versus outside Indian reservations. Findings The average per pack prices paid differed substantially by price-minimizing strategy. Smokers who used any type of price-minimizing strategies paid substantially less than those who did not use these strategies (P < 0.05). Premium brand users who purchased by pack in places outside Indian reservations paid the entire amount of the excise tax, together with an additional premium of 7–10 cents per pack for every $1 increase in excise tax (pass-through rate of 1.07–1.10, P < 0.05). In contrast, carton purchasers, generic brand users or those who were likely to make their purchases on Indian reservations paid only 30–83 cents per pack for every $1 tax increase (pass-through rate of 0.30–0.83, P < 0.05). Conclusions Many smokers in the United States are able to avoid the full impact of state excise tax on cost of smoking by buying cartons, using generic brands and buying from Indian reservations. PMID:24861973

Stabilizing the hexagonal close packed structure of hard spheres with polymers: Phase diagram, structure, and dynamics

NASA Astrophysics Data System (ADS)

Edison, John R.; Dasgupta, Tonnishtha; Dijkstra, Marjolein

2016-08-01

We study the phase behaviour of a binary mixture of colloidal hard spheres and freely jointed chains of beads using Monte Carlo simulations. Recently Panagiotopoulos and co-workers predicted [Nat. Commun. 5, 4472 (2014)] that the hexagonal close packed (HCP) structure of hard spheres can be stabilized in such a mixture due to the interplay between polymer and the void structure in the crystal phase. Their predictions were based on estimates of the free-energy penalty for adding a single hard polymer chain in the HCP and the competing face centered cubic (FCC) phase. Here we calculate the phase diagram using free-energy calculations of the full binary mixture and find a broad fluid-solid coexistence region and a metastable gas-liquid coexistence region. For the colloid-monomer size ratio considered in this work, we find that the HCP phase is only stable in a small window at relatively high polymer reservoir packing fractions, where the coexisting HCP phase is nearly close packed. Additionally we investigate the structure and dynamic behaviour of these mixtures.

Volatile Removal Assembly Flight Experiment and KC-135 Packed Bed Experiment: Results and Lessons Learned

NASA Technical Reports Server (NTRS)

Holder, Donald W.; Parker, David

2000-01-01

The Volatile Removal Assembly (VRA) is a high temperature catalytic oxidation process that will be used as the final treatment for recycled water aboard the International Space Station (ISS). The multiphase nature of the process had raised concerns as to the performance of the VRA in a microgravity environment. To address these concerns, two experiments were designed. The VRA Flight Experiment (VRAFE) was designed to test a full size VRA under controlled conditions in microgravity aboard the SPACEHAB module and in a 1 -g environment and compare the performance results. The second experiment relied on visualization of two-phase flow through small column packed beds and was designed to fly aboard NASA's microgravity test bed plane (KC-135). The objective of the KC-135 experiment was to understand the two-phase fluid flow distribution in a packed bed in microgravity. On Space Transportation System (STS) flight 96 (May 1999), the VRA FE was successfully operated and in June 1999 the KC-135 packed bed testing was completed. This paper provides an overview of the experiments and a summary of the results and findings.

Medicines discarded in household garbage: analysis of a pharmaceutical waste sample in Vienna

PubMed Central

2014-01-01

Objectives To analyze a sample of pharmaceutical waste drawn from household garbage in Vienna, with the aim to learn whether and which medicines end up unused in normal household waste. Methods We obtained a pharmaceutical waste sample from the Vienna Municipal Waste Department. This was drawn by their staff in a representative search in October and November 2009. We did a manual investigation of the sample which contained packs and loose blisters, excluded medical devices and traced loose blisters back to medicines packs. We reported information on the prescription status, origin, therapeutic group, dose form, contents and expiry date. We performed descriptive statistics for the total data set and for sub-groups (e.g. items still containing some of original content). Results In total, 152 packs were identified, of which the majority was prescription-only medicines (74%). Cardiovascular medicines accounted for the highest share (24%). 87% of the packs were in oral form. 95% of the packs had not expired. 14.5% of the total data set contained contents but the range of content left in the packs varied. Results on the packs with contents differed from the total: the shares of Over-the Counter medicines (36%), of medicines of the respiratory system (18%) and of the musculo-skeletal system (18%), for dermal use (23%) and of expired medicines (19%) were higher compared to the full data set. Conclusions The study showed that some medicines end up unused or partially used in normal household garbage in Vienna. Our results did not confirm speculations about a high percentage of unused medicines improperly discarded. There is room for improved patient information and counseling to enhance medication adherence and a proper discharge of medicines. PMID:25848546

Medicines discarded in household garbage: analysis of a pharmaceutical waste sample in Vienna.

PubMed

Vogler, Sabine; Leopold, Christine; Zuidberg, Christel; Habl, Claudia

2014-01-01

To analyze a sample of pharmaceutical waste drawn from household garbage in Vienna, with the aim to learn whether and which medicines end up unused in normal household waste. We obtained a pharmaceutical waste sample from the Vienna Municipal Waste Department. This was drawn by their staff in a representative search in October and November 2009. We did a manual investigation of the sample which contained packs and loose blisters, excluded medical devices and traced loose blisters back to medicines packs. We reported information on the prescription status, origin, therapeutic group, dose form, contents and expiry date. We performed descriptive statistics for the total data set and for sub-groups (e.g. items still containing some of original content). In total, 152 packs were identified, of which the majority was prescription-only medicines (74%). Cardiovascular medicines accounted for the highest share (24%). 87% of the packs were in oral form. 95% of the packs had not expired. 14.5% of the total data set contained contents but the range of content left in the packs varied. Results on the packs with contents differed from the total: the shares of Over-the Counter medicines (36%), of medicines of the respiratory system (18%) and of the musculo-skeletal system (18%), for dermal use (23%) and of expired medicines (19%) were higher compared to the full data set. The study showed that some medicines end up unused or partially used in normal household garbage in Vienna. Our results did not confirm speculations about a high percentage of unused medicines improperly discarded. There is room for improved patient information and counseling to enhance medication adherence and a proper discharge of medicines.

Quantitative characterization of new supramolecular synthons involving fluorine atoms in the crystal structures of di- and tetrafluorinated benzamides.

PubMed

Mondal, Pradip Kumar; Yadav, Hare Ram; Choudhury, Angshuman Roy; Chopra, Deepak

2017-10-01

Strong hydrogen bonds play a significant role in crystal packing. In particular, the involvement of interactions involving fluorine in controlling the crystal packing requires appropriate attention, especially in the presence of other strong hydrogen bonds. In the present study, a detailed quantitative assessment has been performed of the nature, energetics and topological properties derived from the electron density in model compounds based on fluorinated benzamides (a total of 46 fluorine-substituted benzamides containing multiple fluorine atoms) in the solid state. The primary motivation in the design of such molecules is to enhance the acidity of the interacting H atoms in the presence of an increasing number of F atoms on the molecular scaffold, resulting in increased propensity towards the formation of intermolecular interactions involving organic fluorine. This exercise has resulted in the identification of new and frequently occurring supramolecular synthons involving F atoms in the packing of molecules in the solid state. The energetics associated with short and directional intermolecular Csp 2 -H...F-Csp 2 interactions with significantly high electrostatic contributions is noteworthy, and the topological analysis reveals the bonding character of these ubiquitous interactions in crystal packing in addition to the presence of Csp 2 -F...F-Csp 2 contacts.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kuz'mina, L. G., E-mail: kuzmina@igic.ras.ru; Gunina, M. A.; Churakov, A. V.

Two aromatic esters with the formulas C{sub 6}H{sub 13}-O-C{sub 6}H{sub 4}-C(O)O-C{sub 6}H{sub 4}-O-C{sub 7}H{sub 15} (1) and C{sub 7}H{sub 15}-O-C{sub 6}H{sub 4}-C(O)O-C{sub 6}H{sub 4}-O-C{sub 4}H{sub 9} (2) belonging to nematic liquid-crystal compounds were studied by X-ray diffraction. Compound 1 crystallizes in two modifications: monoclinic (1-m) and triclinic (1-tr). The crystal packing of 1 and 2 is built from alternating loosely packed aliphatic regions and closely packed aromatic regions. In crystal structures 1-m and 2, the aromatic regions are linked into chains by hydrogen bonds with the participation of the carbonyl oxygen atom of the ester group and the C-H fragmentmore » of the benzene ring, but these hydrogen bonds in 1-m are much weaker than in 2. In 1-m there are {pi}-stacking interactions between the molecules, resulting in the formation of centrosymmetric dimers with an interplanar distance of 3.45 A. In 1-tr, the aromatic fragments form a herringbone packing motif favorable for a two-dimensional network of directional C-H...{pi}-system interactions.« less

Vibrational spectroscopy and microscopic imaging: novel approaches for comparing barrier physical properties in native and human skin equivalents.

PubMed

Yu, Guo; Zhang, Guojin; Flach, Carol R; Mendelsohn, Richard

2013-06-01

Vibrational spectroscopy and imaging have been used to compare barrier properties in human skin, porcine skin, and two human skin equivalents, Epiderm 200X with an enhanced barrier and Epiderm 200 with a normal barrier. Three structural characterizations were performed. First, chain packing and conformational order were compared in isolated human stratum corneum (SC), isolated porcine SC, and in the Epiderm 200X surface layers. The infrared (IR) spectrum of isolated human SC revealed a large proportion of orthorhombically packed lipid chains at physiological temperatures along with a thermotropic phase transition to a state with hexagonally packed chains. In contrast, the lipid phase at physiological temperatures in both porcine SC and in Epiderm 200X, although dominated by conformationally ordered chains, lacked significant levels of orthorhombic subcell packing. Second, confocal Raman imaging of cholesterol bands showed extensive formation of cholesterol-enriched pockets within the human skin equivalents (HSEs). Finally, IR imaging tracked lipid barrier dimensions as well as the spatial disposition of ordered lipids in human SC and Epiderm 200X. These approaches provide a useful set of experiments for exploring structural differences between excised human skin and HSEs, which in turn may provide a rationale for the functional differences observed among these preparations.

Polyether ether ketone encased monolith frits made of polyether ether ketone tubing with a 0.25 mm opening resulting in an improved separation performance in liquid chromatography.

PubMed

Park, Sin Young; Cheong, Won Jo

2016-05-01

Tiny polyether ether ketone encased monolith frits have been prepared by modified catalytic sulfonation of the inner surface of polyether ether tubing (1.6 mm od, 0.25 mm id) followed by modified formation of organic monolith and cutting of the tubing into slices. The frit was placed below the central hole of the column outlet union and supported by a combination of a silica capillary (0.365 mm od, 0.05 mm id) and a polyether ether ketone sleeve (1.6 mm od, 0.38 mm id) tightened with a nut and a ferrule when the column was packed to prevent sinking of the frit element into the union hole (0.25 mm opening) otherwise. The column packed this way with the frits investigated in this study has shown better separation performance owing to the reduced frit volume in comparison to the column packed with a commercial stainless-steel screen frit. This study establishes the strategy of disposable microcolumns in which cheap disposable frits are used whenever the column is re-packed to yield columns of even better chromatographic performance than the columns with commercial frits. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Transformation of BCC and B2 High Temperature Phases to HCP and Orthorhombic Structures in the Ti-Al-Nb System. Part II: Experimental TEM Study of Microstructures

PubMed Central

Bendersky, L. A.; Boettinger, W. J.

1993-01-01

Possible transformation paths that involve no long range diffusion and their corresponding microstructural details were predicted by Bendersky, Roytburd, and Boettinger [J. Res. Natl. Inst. Stand. Technol. 98, 561 (1993)] for Ti-Al-Nb alloys cooled from the high temperature BCC/B2 phase field into close-packed orthorhombic or hexagonal phase fields. These predictions were based on structural and symmetry relations between the known phases. In the present paper experimental TEM results show that two of the predicted transformation paths are indeed followed for different alloy compositions. For Ti-25Al-12.5Nb (at%), the path includes the formation of intermediate hexagonal phases, A3 and DO19, and subsequent formation of a metastable domain structure of the low-temperature O phase. For alloys close to Ti-25Al-25Nb (at%), the path involves an intermediate B19 structure and subsequent formation of a translational domain structure of the O phase. The path selection depends on whether B2 order forms in the high temperature cubic phase prior to transformation to the close-packed structure. The paper also analyzes the formation of a two-phase modulated microstructure during long term annealing at 700 °C. The structure forms by congruent ordering of the DO19 phase to the O phase, and then reprecipitation of the DO19 phase, possibly by a spinodal mechanism. The thermodynamics underlying the path selection and the two-phase formation are also discussed. PMID:28053488

Monitoring bacterially induced calcite precipitation in porous media using magnetic resonance imaging and flow measurements

NASA Astrophysics Data System (ADS)

Sham, E.; Mantle, M. D.; Mitchell, J.; Tobler, D. J.; Phoenix, V. R.; Johns, M. L.

2013-09-01

A range of nuclear magnetic resonance (NMR) techniques are employed to provide novel, non-invasive measurements of both the structure and transport properties of porous media following a biologically mediated calcite precipitation reaction. Both a model glass bead pack and a sandstone rock core were considered. Structure was probed using magnetic resonance imaging (MRI) via a combination of quantitative one-dimensional profiles and three-dimensional images, applied before and after the formation of calcite in order to characterise the spatial distribution of the precipitate. It was shown through modification and variations of the calcite precipitation treatment that differences in the calcite fill would occur but all methods were successful in partially blocking the different porous media. Precipitation was seen to occur predominantly at the inlet of the bead pack, whereas precipitation occurred almost uniformly along the sandstone core. Transport properties are quantified using pulse field gradient (PFG) NMR measurements which provide probability distributions of molecular displacement over a set observation time (propagators), supplementing conventional permeability measurements. Propagators quantify the local effect of calcite formation on system hydrodynamics and the extent of stagnant region formation. Collectively, the combination of NMR measurements utilised here provides a toolkit for determining the efficacy of a biological-precipitation reaction for partially blocking porous materials.

Heat-induced formation of a specific binding site for self-assembled Congo Red in the V domain of immunoglobulin L chain lambda.

PubMed

Piekarska, B; Konieczny, L; Rybarska, J; Stopa, B; Zemanek, G; Szneler, E; Król, M; Nowak, M; Roterman, I

2001-11-01

Moderate heating (40-50 degrees C) of immunoglobulins makes them accessible for binding with Congo Red and some related highly associated dyes. The binding is specific and involves supramolecular dye ligands presenting ribbon-like micellar bodies. The L chain lambda dimer, which upon heating disclosed the same binding requirement with respect to supramolecular dye ligands, was used in this work to identify the site of their attachment. Two clearly defined dye-protein (L lambda chain) complexes arise upon heating, here called complex I and complex II. The first is formed at low temperatures (up to 40-45 degrees C) and hence by a still native protein, while the formation of the second one is associated with domain melting above 55 degrees C. They contain 4 and 8 dye molecules bound per L chain monomer, respectively. Complex I also forms efficiently at high dye concentration even at ambient temperature. Complex I and its formation was the object of the present studies. Three structural events that could make the protein accessible to penetration by the large dye ligand were considered to occur in L chains upon heating: local polypeptide chain destabilization, VL-VL domain incoherence, and protein melting. Of these three possibilities, local low-energy structural alteration was found to correlate best with the formation of complex I. It was identified as decreased packing stability of the N-terminal polypeptide chain fragment, which as a result made the V domain accessible for dye penetration. The 19-amino acid N-terminal fragment becomes susceptible to proteolytic cleavage after being replaced by the dye at its packing locus. Its splitting from the dye-protein complex was proved by amino acid sequence analysis. The emptied packing locus, which becomes the site that holds the dye, is bordered by strands of amino acids numbered 74-80 and 105-110, as shown by model analysis. The character of the temperature-induced local polypeptide chain destabilization and its possible role in intramolecular antibody signaling is discussed. Copyright 2001 John Wiley & Sons, Inc.

Content and distribution of noncollagenous matrix proteins in bone and cementum: relationship to speed of formation and collagen packing density.

PubMed

Nanci, A

1999-06-30

The organic matrix of collagen-based calcified tissues consists of a supporting collagen meshwork and various noncollagenous matrix proteins (NCPs). Together, they contribute to determining the structure and biomechanical properties of the tissue. Their respective organization and interrelation can advantageously be examined by immunocytochemistry, an approach which allows correlation of composition with structure. The aim of this article is to review postembedding immuno- and lectin-gold-labeling data on the characterization of the noncollagenous compartment in rat and human bone and cementum, and on its relationship to collagen. The two major NCPs, bone sialoprotein and osteopontin, generally codistribute and accumulate in cement lines and in the spaces among the mineralized collagen fibrils. However, there are variations in their distribution and density of labeling throughout the tissue. Indeed, bone and cementum can form in environments that are either poor or enriched in NCPs. The amount of NCPs generally correlates with bone and cementum types and with speed of formation of the tissue and packing density of collagen fibrils. Taken together, the data suggest that production of both collagenous and noncollagenous constituents can be "modulated" during formation of collagen-based calcified tissues. It is concluded that, in addition to structural and compositional parameters, tissue dynamics must be taken into consideration in order to understand the significance of the apparent accumulation of NCPs at some sites and to determine the mechanisms of normal and pathological calcified tissue formation. Copyright 1999 Academic Press.

Unit: Charge, Inspection Pack, National Trial Print. Reference No. 214.

ERIC Educational Resources Information Center

Australian Science Education Project, Toorak, Victoria.

This physical science unit from the Australian Science Education Project (ASEP) focuses on electrostatics. After students complete the activities contained in the core of the unit, they have six optional activities to pursue: How do charged objects behave? (conductors, insulators, charged objects); What is blue? (formation of copper ion); Putting…

Design of Formats and Packs of Catalog Cards.

ERIC Educational Resources Information Center

OCLC Online Computer Library Center, Inc., Dublin, OH.

The three major functions of the Ohio College Library Center's Shared Cataloging System are: 1) provision of union catalog location listing; 2) making available cataloging done by one library to all other users of the system; and 3) production of catalog cards. The system, based on a central machine readable data base, speeds cataloging and…

[Role of smoking in bronchopulmonary disease formation in nickel production workers].

PubMed

Rocheva, I I; Siurin, S A; Nikanov, A N; Panychev

2007-01-01

Questionnaire and external respiration studies in 295 workers engaged into nickel production (including 158 smokers and 137 nonsmokers) revealed that smoking (7.92 +/- 0.63 packs/year in average) causes clinical symptoms of broncho-pulmonary diseases, lower functional parameters, increased risk of acute and chronic respiratory diseases preceding to chronic bronchitis.

"Amazing Planet--Action-Packed Science"

ERIC Educational Resources Information Center

Devon, Elizabeth; Kennett, Peter; King, Chris

2013-01-01

This description features a set of lively demonstrations and observations, including some group work, that illustrate features of Earth science such as the Earth's rotation, ocean currents, the formation and erosion of rocks, earthquakes and volcanoes. All were shown in a one-hour presentation to teachers and can readily be used in schools,…

Electrostatic Interactions between Elongated Monomers Drive Filamentation of Drosophila Shrub, a Metazoan ESCRT-III Protein.

PubMed

McMillan, Brian J; Tibbe, Christine; Jeon, Hyesung; Drabek, Andrew A; Klein, Thomas; Blacklow, Stephen C

2016-08-02

The endosomal sorting complex required for transport (ESCRT) is a conserved protein complex that facilitates budding and fission of membranes. It executes a key step in many cellular events, including cytokinesis and multi-vesicular body formation. The ESCRT-III protein Shrub in flies, or its homologs in yeast (Snf7) or humans (CHMP4B), is a critical polymerizing component of ESCRT-III needed to effect membrane fission. We report the structural basis for polymerization of Shrub and define a minimal region required for filament formation. The X-ray structure of the Shrub core shows that individual monomers in the lattice interact in a staggered arrangement using complementary electrostatic surfaces. Mutations that disrupt interface salt bridges interfere with Shrub polymerization and function. Despite substantial sequence divergence and differences in packing interactions, the arrangement of Shrub subunits in the polymer resembles that of Snf7 and other family homologs, suggesting that this intermolecular packing mechanism is shared among ESCRT-III proteins. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Spatial arrangement of legionella colonies in intact biofilms from a model cooling water system.

PubMed

Taylor, Michael; Ross, Kirstin; Bentham, Richard

2013-01-01

There is disagreement among microbiologists about whether Legionella requires a protozoan host in order to replicate. This research sought to determine where in biofilm Legionellae are found and whether all biofilm associated Legionella would be located within protozoan hosts. While it is accepted that Legionella colonizes biofilm, its life cycle and nutritional fastidiousness suggest that Legionella employs multiple survival strategies to persist within microbial systems. Fluorescent in situ hybridization (FISH) and confocal laser scanning microscopy (CLSM) demonstrated an undulating biofilm surface architecture and a roughly homogenous distribution of heterotrophic bacteria with clusters of protozoa. Legionella displayed 3 distinct spatial arrangements either contained within or directly associated with protozoa, or dispersed in loosely associated clusters or in tightly packed aggregations of cells forming dense colonial clusters. The formation of discreet clusters of tightly packed Legionella suggests that colony formation is influenced by specific environmental conditions allowing for limited extracellular replication. This work represents the first time that an environmentally representative, multispecies biofilm containing Legionella has been fluorescently tagged and Legionella colony morphology noted within a complex microbial system.

Impact of interaction range and curvature on crystal growth of particles confined to spherical surfaces.

PubMed

Paquay, Stefan; Both, Gert-Jan; van der Schoot, Paul

2017-07-01

When colloidal particles form a crystal phase on a spherical template, their packing is governed by the effective interaction between them and the elastic strain of bending the growing crystal. For example, if growth commences under appropriate conditions, and the isotropic crystal that forms reaches a critical size, growth continues via the incorporation of defects to alleviate elastic strain. Recently, it was experimentally found that, if defect formation is somehow not possible, the crystal instead continues growing in ribbons that protrude from the original crystal. Here we report on computer simulations in which we observe both the formation of ribbons at short interaction ranges and packings that incorporate defects if the interaction is longer-ranged. The ribbons only form above some critical crystal size, below which the nucleus is disk-shaped. We find that the scaling of the critical crystal size differs slightly from the one proposed in the literature, and we argue that this is because the actual morphology transition is caused by the competition between line tension and elastic stress, rather than the competition between chemical potential and elastic stress.

Impact of interaction range and curvature on crystal growth of particles confined to spherical surfaces

NASA Astrophysics Data System (ADS)

Paquay, Stefan; Both, Gert-Jan; van der Schoot, Paul

2017-07-01

When colloidal particles form a crystal phase on a spherical template, their packing is governed by the effective interaction between them and the elastic strain of bending the growing crystal. For example, if growth commences under appropriate conditions, and the isotropic crystal that forms reaches a critical size, growth continues via the incorporation of defects to alleviate elastic strain. Recently, it was experimentally found that, if defect formation is somehow not possible, the crystal instead continues growing in ribbons that protrude from the original crystal. Here we report on computer simulations in which we observe both the formation of ribbons at short interaction ranges and packings that incorporate defects if the interaction is longer-ranged. The ribbons only form above some critical crystal size, below which the nucleus is disk-shaped. We find that the scaling of the critical crystal size differs slightly from the one proposed in the literature, and we argue that this is because the actual morphology transition is caused by the competition between line tension and elastic stress, rather than the competition between chemical potential and elastic stress.

Rational design of a molecularly imprinted polymer for dinotefuran: theoretical and experimental studies aimed at the development of an efficient adsorbent for microextraction by packed sorbent.

PubMed

Silva, Camilla Fonseca; Borges, Keyller Bastos; do Nascimento, Clebio Soares

2017-12-18

In this work, we studied theoretically the formation process of a molecularly imprinted polymer (MIP) for dinotefuran (DNF), testing distinct functional monomers (FM) in various solvents through density functional theory calculations. The results revealed that the best conditions for MIP synthesis were established with methacrylic acid (MAA) as FM in a 1 : 4 stoichiometry and with chloroform as the solvent. This protocol showed the most favourable stabilization energies for the pre-polymerization complexes. Furthermore, the formation of the FM/template complex is enthalpy driven and the occurrence of hydrogen bonds between the DNF and MAA plays a major role in the complex stability. To confirm the theoretical results, MIP was experimentally synthesized considering the best conditions found at the molecular level and characterized by scanning electron microscopy and thermogravimetric analysis. After that, the synthesized material was efficiently employed in microextraction by packed sorbent combined with high-performance liquid chromatography in a preliminary study of the recovery of DNF from water and artificial saliva samples.

Granular compaction and the topology of pore deformation

NASA Astrophysics Data System (ADS)

Saadatfar, Mohammad; Takeuchi, Hiroshi; Hanifpour, Maryam; Robins, Vanessa; Francois, Nicolas; Hiraoka, Yasuaki

2017-06-01

The mechanism of crystallisation in highly dissipative materials such as foams or granular materials is still widely unknown. In macroscopic granular materials high levels of energy need to be injected to overcome the natural propensity of these dissipative materials to form amorphous structures [1, 2]. The transition from disordered to ordered packings in such systems triggers a wide range of geometrical, topological and mechanical changes at multi length scales [3]. Formation of cavities and patterns by aggregates of grains and their evolution during this transition requires a complete topological description of the system. Here, crystallisation of three-dimensional packings of frictional spheres is studied at the grain scale with x-ray tomography. Using a novel and powerful topological tool, Persistent Homology, we describe the complete formation process of perfect tetrahedral and octahedral patterns: the two building blocks of FCC and HCP crystalline arrangements. Additionally we present possible and allowable deformations of these components that accurately reproduce the main topological features of the system. These results give new insights into the crystallisation of these highly dissipative materials.

STS-97 Mission Specialist Garneau with full launch and entry suit during pre-pack and fit check

NASA Technical Reports Server (NTRS)

2000-01-01

During pre-pack and fit check in the Operations and Checkout Building, STS-97 Commander Brent Jett gets help with his gloves from suit technician Bill Todd. Mission STS-97 is the sixth construction flight to the International Space Station. Its payload includes the P6 Integrated Truss Structure and a photovoltaic (PV) module, with giant solar arrays that will provide power to the Station. The mission includes two spacewalks to complete the solar array connections. STS-97 is scheduled to launch Nov. 30 at about 10:06 p.m. EST.

Some tradeoffs in ingot shaping and price of solar photovoltaic modules

NASA Technical Reports Server (NTRS)

Daud, T.

1982-01-01

Growth of round ingots is cost-effective for sheets but leaves unused space when round cells are packed into a module. This reduces the packing efficiency, which approaches 95% for square cells, to about 78% and reduces the conversion efficiency of the module by the same ratio. Shaping these ingots into squares with regrowth of cut silicon improves the packing factor, but increases growth cost. The cost impact on solar cell modules was determined by considering shaping ingots in stages from full round to complete square. The sequence of module production with relevant price allocation guidelines is outlined. The severe penalties in add-on price due to increasing slice thickness and kerf are presented. Trade-offs between advantages of recycling silicon and shaping costs are developed for different slicing scenarios. It is shown that shaping results in cost saving of up to 21% for a 15 cm dia. ingot.

Ni-Al phase transformation of dual layer coating prepared by pack cementation and electrodeposition

NASA Astrophysics Data System (ADS)

Afandi, A.; Sugiarti, E.; Ekaputra, R.; Sudiro, T.; Thosin, K. A. Z.

2018-03-01

In this work, Fe-Cr alloys were coated via Aluminum (Al) pack cementation, followed by Nickel (Ni) electrodeposition. The process of pack cementation was done with mixing powders of Al, Al203 and NH4Cl with weight percentage of 15%, 85%, and 5% respectively. To control successful Al diffusion to the substrate, pack cementation was conducted for 7 hours with two holding temperatures treatment at 400 °C for 4 hours, and 800 ° C hours for 2 hours. Subsequently, the electrodeposition of Ni was applied with the solution consisting of NiSO4, H3BO3, and NiCl2. The samples were placed in the cathode, and then dipped in the solutions, while Ni plate used as anode. Successfully the samples were coated by dual Al-Ni layers, the samples were slowly heat treated at 900 °C for 10 hours. The inter-diffusion of Al and Ni were characterized with SEM/EDX to investigate the distribution of the elements. Mechanical properties of the coated substrates were analyzed with Hardness Vickers (HV). It was found the hardness of the substrate increased significantly, from originally 255 HV to the 1177 HV after pack cementation. The hardness of the substrates has decreased to 641 HV after Ni plating, but subsequent heat treatment has been able to increase the hardness to 842 HV. This phenomenon can be correlated to the inward Al diffusion, and outward Fe, Cr diffusion. The formation of intermetallic compounds due to Al inward and Fe, Cr outward diffusion were discussed in details.

Supramolecular Packing Controls H 2 Photocatalysis in Chromophore Amphiphile Hydrogels

DOE PAGES

Weingarten, Adam S.; Kazantsev, Roman V.; Palmer, Liam C.; ...

2015-11-21

Light harvesting supramolecular assemblies are potentially useful structures as components of solar-to-fuel conversion materials. The development of these functional constructs requires an understanding of optimal packing modes for chromophores. Here, we investigated assembly in water and the photocatalytic function of perylene monoimide chromophore amphiphiles with different alkyl linker lengths separating their hydrophobic core and the hydrophilic carboxylate headgroup. We found that these chromophore amphiphiles (CAs) self-assemble into charged nanostructures of increasing aspect ratio as the linker length is increased. The addition of salt to screen the charged nanostructures induced the formation of hydrogels and led to internal crystallization within somemore » of the nanostructures. For linker lengths up to seven methylenes, the CAs were found to pack into 2D crystalline unit cells within ribbon-shaped nanostructures, whereas the nine methylene CAs assembled into long nanofibers without crystalline molecular packing. At the same time, the different molecular packing arrangements after charge screening led to different absorbance spectra, despite the identical electronic properties of all PMI amphiphiles. While the crystalline CAs formed electronically coupled H-aggregates, only CAs with intermediate linker lengths showed evidence of high intermolecular orbital overlap. Photocatalytic hydrogen production using a nickel-based catalyst was observed in all hydrogels, with the highest turnovers observed for CA gels having intermediate linker lengths. Lastly, we conclude that the improved photocatalytic performance of the hydrogels formed by supramolecular assemblies of the intermediate linker CA molecules likely arises from improved exciton splitting efficiencies due to their higher orbital overlap.« less

Does every US smoker bear the same cigarette tax?

PubMed

Xu, Xin; Malarcher, Ann; O'Halloran, Alissa; Kruger, Judy

2014-10-01

To evaluate state cigarette excise tax pass-through rates for selected price-minimizing strategies. Multivariate regression analysis of current smokers from a stratified, national, dual-frame telephone survey. United States. A total of 16 542 adult current smokers aged 18 years or older. Cigarette per pack prices paid with and without coupons were obtained for pack versus carton purchase, use of generic brands versus premium brands, and purchase from Indian reservations versus outside Indian reservations. The average per pack prices paid differed substantially by price-minimizing strategy. Smokers who used any type of price-minimizing strategies paid substantially less than those who did not use these strategies (P < 0.05). Premium brand users who purchased by pack in places outside Indian reservations paid the entire amount of the excise tax, together with an additional premium of 7-10 cents per pack for every $1 increase in excise tax (pass-through rate of 1.07-1.10, P < 0.05). In contrast, carton purchasers, generic brand users or those who were likely to make their purchases on Indian reservations paid only 30-83 cents per pack for every $1 tax increase (pass-through rate of 0.30-0.83, P < 0.05). Many smokers in the United States are able to avoid the full impact of state excise tax on cost of smoking by buying cartons, using generic brands and buying from Indian reservations. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

Oxygen supply for CHO cells immobilized on a packed-bed of Fibra-Cel disks.

PubMed

Meuwly, F; Loviat, F; Ruffieux, P-A; Bernard, A R; Kadouri, A; von Stockar, U

2006-03-05

Packed-bed bioreactors (PBR) have proven to be efficient systems to culture mammalian cells at very high cell density in perfusion mode, thus leading to very high volumetric productivity. However, the immobilized cells must be continuously supplied with all nutrients in sufficient quantities to remain viable and productive over the full duration of the perfusion culture. Among all nutrients, oxygen is the most critical since it is present at very low concentration due to its low solubility in cell culture medium. This work presents the development of a model for oxygenation in a packed-bed bioreactor system. The experimental system used to develop the model was a packed-bed of Fibra-Cel disk carriers used to cultivate Chinese Hamster Ovary cells at high density ( approximately 6.1 x 10(7) cell/mL) in perfusion mode. With the help of this model, it was possible to identify if a PBR system is operated in optimal or sub-optimal conditions. Using the model, two options were proposed, which could improve the performance of the basal system by about twofold, that is, by increasing the density of immobilized cells per carrier volume from 6.1 x 10(7) to 1.2 x 10(8) cell/mL, or by increasing the packed-bed height from 0.2 to 0.4 m. Both strategies would be rather simple to test and implement in the packed-bed bioreactor system used for this study. As a result, it would be possible to achieve a substantial improvement of about twofold higher productivity as compared with the basal conditions.

Close-packed monolayer self-assembly of silica nanospheres assisted by infrared irradiation

NASA Astrophysics Data System (ADS)

Minh, Nguyen Van; Hue, Nguyen Thi; Lien, Nghiem Thi Ha; Hoang, Chu Manh

2018-01-01

In this paper, we report on a fast and cost-effective drop coating technique for the self-assembly of silica nano-spheres from a mono-dispersed colloidal suspension into close-packed monolayer (CMP) on hydrophilic single-crystal silicon substrate. The technique includes the self-assembly of silica nano-spheres on slanted silicon substrate and infrared irradiation during evaporation process of the coated droplet. The influence of the substrate slant angle and infrared irradiation on the formation of silica nano-sphere monolayer is investigated. This achievement is promising for various applications, such as a mask layer for nano-sphere lithography that is employed for producing fundamental elements in photonics, plasmonics, and solar cell. [Figure not available: see fulltext.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Streubel, Robert; Kronast, Florian; Reiche, Christopher F.

For this work, we studied curvature-driven modifications to the magnetostatic coupling of vortex circulation and polarity in soft-magnetic closely packed cap arrays. A phase diagram for the magnetic remanent/transition states at room temperature as a function of diameter and thickness was assembled. For specimens with vortex remanent state (40 nm-thick Permalloy on 330 nm spherical nanoparticles), both vortex circulation and polarity were visualized. Intercap coupling upon vortex nucleation leads to the formation of vortex circulation patterns in closely packed arrays. The remanent circulation pattern can be tailored choosing the direction of the applied magnetic field with respect to the symmetrymore » axis of the hexagonal array. An even and random distribution of vortex polarity indicates the absence of any circulation-polarity coupling.« less

Effect of Isothermal Temperature on Growth Behavior of Nanostructured Bainite in Laser Cladded Coatings

PubMed Central

Guo, Yanbing; Yao, Chengwu; Feng, Kai; Li, Zhuguo; Chu, Paul K.; Wu, Yixiong

2017-01-01

The growth and propagation behavior of austenite-to-bainite isothermal transformation in laser-cladded, Si-rich, and Fe-based coatings is investigated. The crystallographic features, orientation relationship at different isothermal temperatures, and the morphology of the nanostructured bainite are determined. The Nishiyama-Wassermann type orientation relationship is observed at a high temperature and at a low temperature, and mixed Nishiyama-Wassermann and Kurdjumov-Sach mechanisms are seen. The growth direction is investigated by the partial dislocation theory and an extrapolated model based on the repeated formation of lenticular-shaped subunits and pile-up along the close-packed directions of the close-packed planes. The variants of the bainite growth directions would be more selective at the high transformation temperature. PMID:28773161

Corrosion Behaviour of Sn-based Lead-Free Solders in Acidic Solution

NASA Astrophysics Data System (ADS)

Nordarina, J.; Mohd, H. Z.; Ahmad, A. M.; Muhammad, F. M. N.

2018-03-01

The corrosion properties of Sn-9(5Al-Zn), Sn-Cu and SAC305 were studied via potentiodynamic polarization method in an acidic solution of 1 M hydrochloric acid (HCl). Sn-9(5Al-Zn) produced different polarization profile compared with Sn-Cu and SAC305. The morphological analysis showed that small, deep grooves shaped of corrosion product formed on top of Sn-9(5Al-Zn) solder while two distinctive structures of closely packed and loosely packed corrosion product formed on top of Sn-Cu and SAC305 solder alloys. Phase analysis revealed the formations of various corrosion products such as SnO and SnO2 mainly dominant on surface of solder alloys after potentiodynamic polarization in 1 M hydrochloric acid (HCl).

DIRECT SOLUTIONS OF THE MAXWELL EQUATIONS EXPLAIN OPPOSITION PHENOMENA OBSERVED FOR HIGH-ALBEDO SOLAR SYSTEM OBJECTS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mishchenko, Michael I.; Liu Li; Dlugach, Janna M.

2009-11-10

Several spectacular backscattering effects observed for particulate planetary surfaces have been interpreted in terms of the effect of weak localization (WL) of electromagnetic waves. However, the interference concept of WL explicitly relies on the notion of phase of an electromagnetic wave and is strictly applicable only when particles forming the surface are widely separated. Therefore, one needs a definitive quantitative proof of the WL nature of specific optical effects observed for densely packed particulate media. We use numerically exact computer solutions of the Maxwell equations to simulate electromagnetic scattering by realistic models consisting of large numbers of randomly positioned, denselymore » packed particles. By increasing the particle packing density from zero to approx40%, we track the onset and evolution of the full suite of backscattering optical effects predicted by the low-density theory of WL, including the brightness and polarization opposition effects (BOE and POE). We find that all manifestations of WL, except the circular polarization ratio and POE, are remarkably immune to packing-density effects. Even POE can survive packing densities typical of planetary regolith surfaces. Our numerical data coupled with the results of unique observations at near-backscattering geometries demonstrate that the BOE and POE detected simultaneously for high-albedo solar system objects are caused by the effect of WL.« less

TS-SRP/PACK - COMPUTER PROGRAMS TO CHARACTERIZE ALLOYS AND PREDICT CYCLIC LIFE USING THE TOTAL STRAIN VERSION OF STRAINRANGE PARTITIONING

NASA Technical Reports Server (NTRS)

Saltsman, J. F.

1994-01-01

TS-SRP/PACK is a set of computer programs for characterizing and predicting fatigue and creep-fatigue resistance of metallic materials in the high-temperature, long-life regime for isothermal and nonisothermal fatigue. The programs use the total strain version of the Strainrange Partitioning (TS-SRP). The user should be thoroughly familiar with the TS-SRP method before attempting to use any of these programs. The document for this program includes a theory manual as well as a detailed user's manual with a tutorial to guide the user in the proper use of TS-SRP. An extensive database has also been developed in a parallel effort. This database is an excellent source of high-temperature, creep-fatigue test data and can be used with other life-prediction methods as well. Five programs are included in TS-SRP/PACK along with the alloy database. The TABLE program is used to print the datasets, which are in NAMELIST format, in a reader friendly format. INDATA is used to create new datasets or add to existing ones. The FAIL program is used to characterize the failure behavior of an alloy as given by the constants in the strainrange-life relations used by the total strain version of SRP (TS-SRP) and the inelastic strainrange-based version of SRP. The program FLOW is used to characterize the flow behavior (the constitutive response) of an alloy as given by the constants in the flow equations used by TS-SRP. Finally, LIFE is used to predict the life of a specified cycle, using the constants characterizing failure and flow behavior determined by FAIL and FLOW. LIFE is written in interpretive BASIC to avoid compiling and linking every time the equation constants are changed. Four out of five programs in this package are written in FORTRAN 77 for IBM PC series and compatible computers running MS-DOS and are designed to read data using the NAMELIST format statement. The fifth is written in BASIC version 3.0 for IBM PC series and compatible computers running MS-DOS version 3.10. The executables require at least 239K of memory and DOS 3.1 or higher. To compile the source, a Lahey FORTRAN compiler is required. Source code modifications will be necessary if the compiler to be used does not support NAMELIST input. Probably the easiest revision to make is to use a list-directed READ statement. The standard distribution medium for this program is a set of two 5.25 inch 360K MS-DOS format diskettes. The contents of the diskettes are compressed using the PKWARE archiving tools. The utility to unarchive the files, PKUNZIP.EXE, is included. TS-SRP/PACK was developed in 1992.

Large format lithium ion pouch cell full thermal characterisation for improved electric vehicle thermal management

NASA Astrophysics Data System (ADS)

Grandjean, Thomas; Barai, Anup; Hosseinzadeh, Elham; Guo, Yue; McGordon, Andrew; Marco, James

2017-08-01

It is crucial to maintain temperature homogeneity in lithium ion batteries in order to prevent adverse voltage distributions and differential ageing within the cell. As such, the thermal behaviour of a large-format 20 Ah lithium iron phosphate pouch cell is investigated over a wide range of ambient temperatures and C rates during both charging and discharging. Whilst previous studies have only considered one surface, this article presents experimental results, which characterise both surfaces of the cell exposed to similar thermal media and boundary conditions, allowing for thermal gradients in-plane and perpendicular to the stack to be quantified. Temperature gradients, caused by self-heating, are found to increase with increasing C rate and decreasing temperature to such an extent that 13.4 ± 0.7% capacity can be extracted using a 10C discharge compared to a 0.5C discharge, both at -10 °C ambient temperature. The former condition causes an 18.8 ± 1.1 °C in plane gradient and a 19.7 ± 0.8 °C thermal gradient perpendicular to the stack, which results in large current density distributions and local state of charge differences within the cell. The implications of these thermal and electrical inhomogeneities on ageing and battery pack design for the automotive industry are discussed.

Pattern formation in a monolayer of magnetic spheres

NASA Astrophysics Data System (ADS)

Stambaugh, Justin; Lathrop, Daniel P.; Ott, Edward; Losert, Wolfgang

2003-08-01

Pattern formation is investigated for a vertically vibrated monolayer of magnetic spheres. The spheres of diameter D encase cylindrical magnetic cores of length l. For large D/l, we find that the particles form a hexagonal-close-packed pattern in which the particles’ dipole vectors assume a macroscopic circulating vortical pattern. For smaller D/l, the particles form concentric rings. The static configurational magnetic energy (which depends on D/l) appears to be a determining factor in pattern selection even though the experimental system is driven and dissipative.

The effect of packing hydrophilization on bacterial attachment and the relationship with the performance of biotrickling filters.

PubMed

Prado, Oscar J; Popat, Sudeep C; Chen, Gexin; Walker, Sharon L; Lafuente, Javier; Gabriel, David; Deshusses, Marc A

2009-08-15

Many bioprocesses depend on the effective formation of a biofilm on a solid support. In the present study, three different surface treatments (sandblasting, pure-O(2) plasma, and He-O(2) plasma treatments) were conducted on polypropylene (PP) Pall rings used as a support in biotrickling filters for air pollution control. The intent was to modify the ring surface and/or electrochemical properties in order to possibly improve cell adhesion, wetting properties, and possibly reduce the start-up time and increase the performance of the biotrickling filters. The surface treatments were found to generally increase the hydrophilicity and the zeta potential of the surfaces. However, the startup and performance of lab-scale biotrickling filters packed with treated Pall rings were not significantly different than the control with untreated rings. Cell and colloid deposition experiments conducted in flow cells showed that the treated surfaces and the hydrodynamic conditions were not favorable for cell deposition indicating that there could be significant opportunities for improving packings used in environmental bioprocess applications. Copyright 2009 Wiley Periodicals, Inc.

Crack-resistant Al2O3–SiO2 glasses

PubMed Central

Rosales-Sosa, Gustavo A.; Masuno, Atsunobu; Higo, Yuji; Inoue, Hiroyuki

2016-01-01

Obtaining “hard” and “crack-resistant” glasses have always been of great important in glass science and glass technology. However, in most commercial glasses both properties are not compatible. In this work, colorless and transparent xAl2O3–(100–x)SiO2 glasses (30 ≤ x ≤ 60) were fabricated by the aerodynamic levitation technique. The elastic moduli and Vickers hardness monotonically increased with an increase in the atomic packing density as the Al2O3 content increased. Although a higher atomic packing density generally enhances crack formation in conventional oxide glasses, the indentation cracking resistance increased by approximately seven times with an increase in atomic packing density in binary Al2O3–SiO2 glasses. In particular, the composition of 60Al2O3•40SiO2 glass, which is identical to that of mullite, has extraordinary high cracking resistance with high elastic moduli and Vickers hardness. The results indicate that there exist aluminosilicate compositions that can produce hard and damage-tolerant glasses. PMID:27053006

Crack-resistant Al2O3-SiO2 glasses

NASA Astrophysics Data System (ADS)

Rosales-Sosa, Gustavo A.; Masuno, Atsunobu; Higo, Yuji; Inoue, Hiroyuki

2016-04-01

Obtaining “hard” and “crack-resistant” glasses have always been of great important in glass science and glass technology. However, in most commercial glasses both properties are not compatible. In this work, colorless and transparent xAl2O3-(100-x)SiO2 glasses (30 ≤ x ≤ 60) were fabricated by the aerodynamic levitation technique. The elastic moduli and Vickers hardness monotonically increased with an increase in the atomic packing density as the Al2O3 content increased. Although a higher atomic packing density generally enhances crack formation in conventional oxide glasses, the indentation cracking resistance increased by approximately seven times with an increase in atomic packing density in binary Al2O3-SiO2 glasses. In particular, the composition of 60Al2O3•40SiO2 glass, which is identical to that of mullite, has extraordinary high cracking resistance with high elastic moduli and Vickers hardness. The results indicate that there exist aluminosilicate compositions that can produce hard and damage-tolerant glasses.

An orphan cbb3-type cytochrome oxidase subunit supports Pseudomonas aeruginosa biofilm growth and virulence

PubMed Central

Jo, Jeanyoung; Cortez, Krista L; Cornell, William Cole; Price-Whelan, Alexa

2017-01-01

Hypoxia is a common challenge faced by bacteria during associations with hosts due in part to the formation of densely packed communities (biofilms). cbb3-type cytochrome c oxidases, which catalyze the terminal step in respiration and have a high affinity for oxygen, have been linked to bacterial pathogenesis. The pseudomonads are unusual in that they often contain multiple full and partial (i.e. ‘orphan’) operons for cbb3-type oxidases and oxidase subunits. Here, we describe a unique role for the orphan catalytic subunit CcoN4 in colony biofilm development and respiration in the opportunistic pathogen Pseudomonas aeruginosa PA14. We also show that CcoN4 contributes to the reduction of phenazines, antibiotics that support redox balancing for cells in biofilms, and to virulence in a Caenorhabditis elegans model of infection. These results highlight the relevance of the colony biofilm model to pathogenicity and underscore the potential of cbb3-type oxidases as therapeutic targets. PMID:29160206

Two-Dimensional Raman Correlation Spectroscopy Study of Poly[(R)-3-hydroxybutyrate- co-(R)-3-hydroxyhexanoate] Copolymers.

PubMed

Noda, Isao; Roy, Anjan; Carriere, James; Sobieski, Brian J; Chase, D Bruce; Rabolt, John F

2017-07-01

Two-dimensional correlation analysis was applied to the time-dependent evolution of Raman spectra during the isothermal crystallization of bioplastic, poly[(R)-3-hydroxybutyrate- co-(R)-3-hydroxyhexanoate] or PHBHx copolymer. Simultaneous Raman measurement of both carbonyl stretching and low-frequency crystalline lattice mode regions made it possible to carry out the highly informative hetero-mode correlation analysis. The crystallization process of PHBHx involves: (1) the early nucleation stage; (2) the primary growth of well-ordered crystals of PHBHx; and (3) the secondary crystal growth phase. The latter stage probably occurs in the inter-lamellar region, with an accompanying reduction of the amorphous component, which occurs most dominantly during the primary crystal growth. The development of a fully formed lamellar structure comprising the 2 1 helices occurs after the primary growth of crystals. In the later stage, secondary inter lamellar space crystallization occurs after the full formation of packed helices comprising the lamellae.

Penetration of nutrition information on food labels across the EU-27 plus Turkey

PubMed Central

Storcksdieck genannt Bonsmann, S; Celemín, L Fernández; Larrañaga, A; Egger, S; Wills, J M; Hodgkins, C; Raats, M M

2010-01-01

Objectives: The European Union (EU)-funded project Food Labelling to Advance Better Education for Life (FLABEL) aims to understand how nutrition information on food labels affects consumers' dietary choices and shopping behaviour. The first phase of this study consisted of assessing the penetration of nutrition labelling and related information on various food products in all 27 EU Member States and Turkey. Methods: In each country, food products were audited in three different types of retailers to cover as many different products as possible within five food and beverage categories: sweet biscuits, breakfast cereals, pre-packed chilled ready meals, carbonated soft drinks and yoghurts. Results: More than 37 000 products were audited in a total of 84 retail stores. On average, 85% of the products contained back-of-pack (BOP) nutrition labelling or related information (from 70% in Slovenia to 97% in Ireland), versus 48% for front-of-pack (FOP) information (from 24% in Turkey to 82% in the UK). The most widespread format was the BOP tabular or linear listing of nutrition content. Guideline daily amounts labelling was the most prevalent form of FOP information, showing an average penetration of 25% across all products audited. Among categories, breakfast cereals showed the highest penetration of nutrition-related information, with 94% BOP penetration and 70% FOP penetration. Conclusions: Nutrition labelling and related information was found on a large majority of products audited. These findings provide the basis for subsequent phases of FLABEL involving attention, reading, liking, understanding and use by consumers of different nutrition labelling formats. PMID:20808336

Role of DNA-DNA Interactions on the Structure and Thermodynamics of Bacteriophages Lambda and P4

PubMed Central

Petrov, Anton S.; Harvey, Stephen C.

2010-01-01

Electrostatic interactions play an important role in both packaging of DNA inside bacteriophages and its release into bacterial cells. While at physiological conditions DNA strands repel each other, the presence of polyvalent cations such as spermine and spermidine in solutions leads to the formation of DNA condensates. In this study, we discuss packaging of DNA into bacteriophages P4 and Lambda under repulsive and attractive conditions using a coarse-grained model of DNA and capsids. Packaging under repulsive conditions leads to the appearance of the coaxial spooling conformations; DNA occupies all available space inside the capsid. Under the attractive potential both packed systems reveal toroidal conformations, leaving the central part of the capsids empty. We also present a detailed thermodynamic analysis of packaging and show that the forces required to pack the genomes in the presence of polyamines are significantly lower than those observed under repulsive conditions. The analysis reveals that in both the repulsive and attractive regimes the entropic penalty of DNA confinement has a significant non-negligible contribution into the total energy of packaging. Additionally we report the results of simulations of DNA condensation inside partially packed Lambda. We found that at low densities DNA behaves as free unconfined polymer and condenses into the toroidal structures; at higher densities rearrangement of the genome into toroids becomes hindered, and condensation results in the formation of non-equilibrium structures. In all cases packaging in a specific conformation occurs as a result of interplay between bending stresses experienced by the confined polymer and interactions between the strands. PMID:21074621

Removal of gasoline volatile organic compounds via air biofiltration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miller, R.S.; Saberiyan, A.G.; Esler, C.T.

1995-12-31

Volatile organic compounds (VOCs) generated by vapor extraction and air-stripping systems can be biologically treated in an air biofiltration unit. An air biofilter consists of one or more beds of packing material inoculated with heterotrophic microorganisms capable of degrading the organic contaminant of concern. Waste gases and oxygen are passed through the inoculated packing material, where the microorganisms will degrade the contaminant and release CO{sub 2} + H{sub 2}O. Based on data obtained from a treatability study, a full-scale unit was designed and constructed to be used for treating gasoline vapors generated by a vapor-extraction and groundwater-treatment system at amore » site in California. The unit is composed of two cylindrical reactors with a total packing volume of 3 m{sup 3}. Both reactors are packed with sphagnum moss and inoculated with hydrocarbon-degrading microorganisms of Pseudomonas and Arthrobacter spp. The two reactors are connected in series for air-flow passage. Parallel lines are used for injection of water, nutrients, and buffer to each reactor. Data collected during the startup program have demonstrated an air biofiltration unit with high organic-vapor-removal efficiency.« less

Impact of Different Front-of-Pack Nutrition Labels on Consumer Purchasing Intentions: A Randomized Controlled Trial.

PubMed

Ducrot, Pauline; Julia, Chantal; Méjean, Caroline; Kesse-Guyot, Emmanuelle; Touvier, Mathilde; Fezeu, Léopold K; Hercberg, Serge; Péneau, Sandrine

2016-05-01

Despite growing evidence supporting the utility of front-of-pack nutrition labels in enabling consumer evaluation of food product healthiness, research on food choices is scarce. This study aims at comparing the impact of front-of-pack nutrition labels on consumers' purchasing intentions. Five-arm, open-label RCT. The study setting was a virtual web-based supermarket, with participants from the French NutriNet-Santé study. The eligibility requirement was grocery shopping involvement. The intervention was to simulate one shopping situation with front-of-pack nutrition labels affixed on food products (December 2014 to March 2015). Participants were randomly assigned to one of five exposure conditions using a central computer system: Guideline Daily Amounts, Multiple Traffic Lights, Five-Color Nutrition Label, Green Tick, or control (no front-of-pack exposure). Given the nature of the intervention, masking of participants was not performed. The primary outcome was the overall nutritional quality of the contents of the shopping cart, estimated using the United Kingdom Food Standards Agency nutrient profiling system. Secondary outcomes included energy and nutrient content of the shopping cart. Impact of the front-of-pack labels was also evaluated across sociodemographic subgroups based on age, educational level, income, and nutrition knowledge. A total of 11,981 participants were included in the analyses (April 2015). The Five-Color Nutrition Label significantly led to the highest overall nutritional quality of the shopping cart, as reflected by lower Food Standards Agency scores (M=8.72; SD=2.75), followed by Multiple Traffic Lights (M=8.97; SD=2.68) and Green Tick (M=8.99; SD=2.71), compared with the control (M=9.34; SD=2.57) (p<0.0001). The Five-Color Nutrition Label was the only front-of-pack format that led to a lower content in lipids, saturated fatty acids, and sodium of the shopping cart (all p<0.05). The impact of the different front-of-pack labels was similar across sociodemographic subgroups. The Five-Color Nutrition Label based on a color-coded and graded scale indicating overall nutritional quality is effective in promoting overall healthier food choices in all population subgroups. This study is registered at www.clinicaltrials.gov NCT02385838. Copyright © 2016 American Journal of Preventive Medicine. Published by Elsevier Inc. All rights reserved.

Fundamental Studies on Two-Phase Gas-Liquid Flows Through Packed Beds in Microgravity

NASA Technical Reports Server (NTRS)

Balakotaiah, Vemuri; McCready, Mark J.; Motil, Brian J.

2002-01-01

In the typical operation of a packed-bed reactor, gas and liquid flow simultaneously through a fixed bed of solid particles. Depending on the application, the particles can be of various shapes and sizes and provide for intimate contact and high rates of transport between the phases needed to sustain chemical or biological reactions. The packing may also serve as either a catalyst or as a support for growing biological material. NASA has flown two of these packed-bed systems in a microgravity environment with limited or no success. The goal of this research is to develop models (with scale-up capability) needed for the design of the physicochemical equipment to carry out these unit operations in microgravity. New insight will also lead to improvements in normal gravity operations. Our initial experiment was flown using an existing KC-135 two-phase flow rig with a modified test section. The test section is a clear polycarbonate rectangular column with a depth of 2.54 cm, a width of 5.08 cm, and 60 cm long. The column was randomly packed with spherical glass beads by slowly dropping the beads into the bed. Even though care was taken in handling the column after it was filled with packing, the alternating high and low gravity cycles with each parabola created a slightly tighter packed bed than is typically reported for this type. By the usual method of comparing the weight difference of a completely dry column versus a column filled with water, the void fraction was found to be .345 for both sizes of beads used. Five flush mounted differential pressure transducers are spaced at even intervals with the first location 4 cm from the inlet port and the subsequent pressure transducers spaced at 13 cm intervals along the column. Differential pressure data was acquired at 1000 Hz to adequately observe pulse formation and characteristics. Visual images of the flow were recorded using a high-speed SVHS system at 500 frames per second. Over 250 different test conditions were evaluated along with a companion set of tests in normal gravity. The flow rates, fluid properties and packing properties were selected to provide a range of several orders-of-magnitude for the important dimensionless parameters. Additional information is included in the original extended abstract.

Compaction of granular materials: numerical simulation of "elastic" compression and pressure solution creep

NASA Astrophysics Data System (ADS)

Bernabe, Y.; Evans, J.

2012-12-01

In a previous work we investigated stress transfer in a pair of grain contacts undergoing pressure solution (PS) creep, showed that stress transfer resulted in a significant decrease in overall strain rate, and concluded that PS creep rates of a randomly packed granular aggregate should be affected by packing evolution and the formation of new contacts during creep. To test these conclusions further, we are numerically simulating the "elastic" hydrostatic compression of a random pack of spheres, using a numerical method similar to that of Cundall and Strack [1979]. We assumed that the spheres were frictionless (i.e., spheres in contact only interacted through normal forces) and that the contact forces obeyed the non-linear Digby [1981] model. In order to determine the PS creep compression of the sphere pack subjected to a constant confining pressure pc, we calculated the thicknesses of the dissolved layers at each individual grain contact during a small time increment and, from these, the overall deformation of the sphere pack. We used an analytical expression discussed in our previous paper and originating from Lehner and Leroy [2004]. During these simulations, we also computed the mean coordination number of the grain contact z, the effective bulk modulus K of the sphere pack and others parameters characterizing the topological and mechanical properties of the sphere assembly. Our results show strong non-linear increase of z and K with pc during "elastic" compression and, with time, during PS creep. The packing rearrangements associated with PS creep produce complex time dependence of the overall deformation ɛ(t). We observed a regular transition from ɛ∝t^3/4 at early times (i.e., less than 0.1 years) and ɛ∝t^1/3 at late times (i.e., more than 1000 years). Cundall, P.A., and O.D.L. Strack (1979), A discrete numerical model for granular assemblies, Geotech., 29, 47-65. Digby, P.J. (1981), The effective elastic moduli of porous rocks, J. Appl. Mech., 48, 803-808. Lehner, F.K., and Y. Leroy (2004), Sandstone compaction by intergranular pressure solution, In Mech. Fluid Saturated Rocks (eds. Y. Guéguen and M. Boutéca), Elsevier.

Improved Characterization of Groundwater Flow in Heterogeneous Aquifers Using Granular Polyacrylamide (PAM) Gel as Temporary Grout

NASA Astrophysics Data System (ADS)

Klepikova, Maria V.; Roques, Clement; Loew, Simon; Selker, John

2018-02-01

The range of options for investigation of hydraulic behavior of aquifers from boreholes has been limited to rigid, cumbersome packers, and inflatable sleeves. Here we show how a new temporary borehole sealing technique using soft grains of polyacrylamide (PAM) gel as a sealing material can be used to investigate natural groundwater flow dynamics and discuss other possible applications of the technology. If no compressive stress is applied, the gel packing, with a permeability similar to open gravel, suppresses free convection, allowing for local temperature measurements and chemical sampling through free-flowing gel packing. Active heating laboratory and field experiments combined with temperature measurements along fiber optic cables were conducted in water-filled boreholes and boreholes filled with soft grains of polyacrylamide gel. The gel packing is shown to minimize the effect of free convection within the well column and enable detection of thin zones of relatively high or low velocity in a highly transmissive alluvial aquifer, thus providing a significant improvement compared to temperature measurements in open boreholes. Laboratory experiments demonstrate that under modest compressive stress to the gel media the permeability transitions from highly permeable to nearly impermeable grouting. Under this configuration the gel packing could potentially allow for monitoring local response pressure from the formation with all other locations in the borehole hydraulically isolated.

Percolation, phase separation, and gelation in fluids and mixtures of spheres and rods

NASA Astrophysics Data System (ADS)

Jadrich, Ryan; Schweizer, Kenneth S.

2011-12-01

The relationship between kinetic arrest, connectivity percolation, structure and phase separation in protein, nanoparticle, and colloidal suspensions is a rich and complex problem. Using a combination of integral equation theory, connectivity percolation methods, naïve mode coupling theory, and the activated dynamics nonlinear Langevin equation approach, we study this problem for isotropic one-component fluids of spheres and variable aspect ratio rigid rods, and also percolation in rod-sphere mixtures. The key control parameters are interparticle attraction strength and its (short) spatial range, total packing fraction, and mixture composition. For spherical particles, formation of a homogeneous one-phase kinetically stable and percolated physical gel is predicted to be possible, but depends on non-universal factors. On the other hand, the dynamic crossover to activated dynamics and physical bond formation, which signals discrete cluster formation below the percolation threshold, almost always occurs in the one phase region. Rods more easily gel in the homogeneous isotropic regime, but whether a percolation or kinetic arrest boundary is reached first upon increasing interparticle attraction depends sensitively on packing fraction, rod aspect ratio and attraction range. Overall, the connectivity percolation threshold is much more sensitive to attraction range than either the kinetic arrest or phase separation boundaries. Our results appear to be qualitatively consistent with recent experiments on polymer-colloid depletion systems and brush mediated attractive nanoparticle suspensions.

Ligand Exchange Governs the Crystal Structures in Binary Nanocrystal Superlattices.

PubMed

Wei, Jingjing; Schaeffer, Nicolas; Pileni, Marie-Paule

2015-11-25

The surface chemistry in colloidal nanocrystals on the final crystalline structure of binary superlattices produced by self-assembly of two sets of nanocrystals is hereby demonstrated. By mixing nanocrystals having two different sizes and the same coating agent, oleylamine (OAM), the binary nanocrystal superlattices that are produced, such as NaCl, AlB2, NaZn13, and MgZn2, are well in agreement with the crystalline structures predicted by the hard-sphere model, their formation being purely driven by entropic forces. By opposition, when large and small nanocrystals are coated with two different ligands [OAM and dodecanethiol (DDT), respectively] while keeping all other experimental conditions unchanged, the final binary structures markedly change and various structures with lower packing densities, such as Cu3Au, CaB6, and quasicrystals, are observed. This effect of the nanocrystals' coating agents could also be extended to other binary systems, such as Ag-Au and CoFe2O4-Ag supracrystalline binary lattices. In order to understand this effect, a mechanism based on ligand exchange process is proposed. Ligand exchange mechanism is believed to affect the thermodynamics in the formation of binary systems composed of two sets of nanocrystals with different sizes and bearing two different coating agents. Hence, the formation of binary superlattices with lower packing densities may be favored kinetically because the required energetic penalty is smaller than that of a denser structure.

Structural evaluation of crystalline ternary γ-cyclodextrin complex.

PubMed

Higashi, Kenjirou; Ideura, Saori; Waraya, Haruka; Moribe, Kunikazu; Yamamoto, Keiji

2011-01-01

The structure of a crystalline γ-cyclodextrin (γ-CD) ternary complex containing salicylic acid (SA) and flurbiprofen (FBP) prepared by sealed heating was investigated. FBP/γ-CD inclusion complex was prepared by coprecipitation; its molar ratio was determined as 1/1. Powder X-ray diffraction measurements showed that the molecular packing of γ-CD changed from hexagonal to monoclinic columnar form by sealed heating of SA with dried FBP/γ-CD inclusion complex, indicating ternary complex formation. The stoichiometry of SA/FBP/γ-CD was estimated as 2/1/1. Solid-state transformation of γ-CD molecular packing upon water vapor adsorption and desorption was irreversible for this ternary complex, in contrast to the reversible transition for the FBP/γ-CD inclusion complex. The ternary complex contained one FBP molecule in the cavity of γ-CD and two SA molecules in the intermolecular space between neighboring γ-CD column stacks. Infrared and (13) C solid-state NMR spectroscopies revealed that the molecular states of SA and FBP changed upon ternary complex formation. In the complex, dimer FBP molecules were sandwiched between two γ-CD molecules whereas each monomer SA molecule was present in the intermolecular space of γ-CD. Ternary complex formation was also observed for other drug-guest systems using naproxen and ketoprofen. Thus, the complex can be used to formulate variety of drugs. Copyright © 2010 Wiley-Liss, Inc. and the American Pharmacists Association

The connectivity of the brain: multi-level quantitative analysis.

PubMed

Murre, J M; Sturdy, D P

1995-11-01

We develop a mathematical formalism or calculating connectivity volumes generated by specific topologies with various physical packing strategies. We consider four topologies (full, random, nearest-neighbor, and modular connectivity) and three physical models: (i) interior packing, where neurons and connection fibers are intermixed, (ii) sheeted packing where neurons are located on a sheet with fibers running underneath, and (iii) exterior packing where the neurons are located at the surfaces of a cube or sphere with fibers taking up the internal volume. By extensive cross-referencing of available human neuroanatomical data we produce a consistent set of parameters for the whole brain, the cerebral cortex, and the cerebellar cortex. By comparing these inferred values with those predicted by the expressions, we draw the following general conclusions for the human brain, cortex, and cerebellum: (i) Interior packing is less efficient than exterior packing (in a sphere). (ii) Fully and randomly connected topologies are extremely inefficient. More specifically we find evidence that different topologies and physical packing strategies might be used at different scales. (iii) For the human brain at a macro-structural level, modular topologies on an exterior sphere approach the data most closely. (iv) On a mesostructural level, laminarization and columnarization are evidence of the superior efficiency of organizing the wiring as sheets. (v) Within sheets, microstructures emerge in which interior models are shown to be the most efficient. With regard to interspecies similarities and differences we conjecture (vi) that the remarkable constancy of number of neurons per underlying square millimeter of cortex may be the result of evolution minimizing interneuron distance in grey matter, and (vii) that the topologies that best fit the human brain data should not be assumed to apply to other mammals, such as the mouse for which we show that a random topology may be feasible for the cortex.

RADON REMOVAL TECHNIQUES FOR SMALL COMMUNITY PUBLIC WATER SUPPLIES

EPA Science Inventory

The report presents the results of an evaluation, performed by the University of New Hampshire--Environmental Research Group (ERG), of radon removal in small community water supplies using full-scale granular activated carbon adsorption, diffused bubble aeration and packed tower ...

Densely-packed ZnTPPs Monolayer on the Rutile TiO2(110)-(1×1) Surface: Adsorption Behavior and Energy Level Alignment

PubMed Central

Rangan, Sylvie; Ruggieri, Charles; Bartynski, Robert; Martínez, José Ignacio; Flores, Fernando; Ortega, José

2016-01-01

The adsorption of a densely packed Zinc(II) tetraphenylporphyrin monolayer on a rutile TiO2(110)-(1×1) surface has been studied using a combination of experimental and theoretical methods, aimed at analyzing the relation between adsorption behavior and barrier height formation. The adsorption configuration of ZnTPP was determined from scanning tunnel microscopy (STM) imaging, density functional theory (DFT) calculations and STM image simulation. The corresponding energy alignment was experimentally determined from X-ray and UV-photoemission spectroscopies and inverse photoemission spectroscopy. These results were found in good agreement with an appropriately corrected DFT model, pointing to the importance of local bonding and intermolecular interactions in the establishment of barrier heights. PMID:26998188

Tunable porous nanoallotropes prepared by post-assembly etching of binary nanoparticle superlattices

NASA Astrophysics Data System (ADS)

Udayabhaskararao, Thumu; Altantzis, Thomas; Houben, Lothar; Coronado-Puchau, Marc; Langer, Judith; Popovitz-Biro, Ronit; Liz-Marzán, Luis M.; Vuković, Lela; Král, Petr; Bals, Sara; Klajn, Rafal

2017-10-01

Self-assembly of inorganic nanoparticles has been used to prepare hundreds of different colloidal crystals, but almost invariably with the restriction that the particles must be densely packed. Here, we show that non-close-packed nanoparticle arrays can be fabricated through the selective removal of one of two components comprising binary nanoparticle superlattices. First, a variety of binary nanoparticle superlattices were prepared at the liquid-air interface, including several arrangements that were previously unknown. Molecular dynamics simulations revealed the particular role of the liquid in templating the formation of superlattices not achievable through self-assembly in bulk solution. Second, upon stabilization, all of these binary superlattices could be transformed into distinct “nanoallotropes”—nanoporous materials having the same chemical composition but differing in their nanoscale architectures.

Plain packaging of cigarettes and smoking behavior: study protocol for a randomized controlled study.

PubMed

Maynard, Olivia M; Leonards, Ute; Attwood, Angela S; Bauld, Linda; Hogarth, Lee; Munafò, Marcus R

2014-06-25

Previous research on the effects of plain packaging has largely relied on self-report measures. Here we describe the protocol of a randomized controlled trial investigating the effect of the plain packaging of cigarettes on smoking behavior in a real-world setting. In a parallel group randomization design, 128 daily cigarette smokers (50% male, 50% female) will attend an initial screening session and be assigned plain or branded packs of cigarettes to smoke for a full day. Plain packs will be those currently used in Australia where plain packaging has been introduced, while branded packs will be those currently used in the United Kingdom. Our primary study outcomes will be smoking behavior (self-reported number of cigarettes smoked and volume of smoke inhaled per cigarette as measured using a smoking topography device). Secondary outcomes measured pre- and post-intervention will be smoking urges, motivation to quit smoking, and perceived taste of the cigarettes. Secondary outcomes measured post-intervention only will be experience of smoking from the cigarette pack, overall experience of smoking, attributes of the cigarette pack, perceptions of the on-packet health warnings, behavior changes, views on plain packaging, and the rewarding value of smoking. Sex differences will be explored for all analyses. This study is novel in its approach to assessing the impact of plain packaging on actual smoking behavior. This research will help inform policymakers about the effectiveness of plain packaging as a tobacco control measure. Current Controlled Trials ISRCTN52982308 (registered 27 June 2013).

Effects of Al addition on atomic structure of Cu-Zr metallic glass

NASA Astrophysics Data System (ADS)

Li, Feng; Zhang, Huajian; Liu, Xiongjun; Dong, Yuecheng; Yu, Chunyan; Lu, Zhaoping

2018-02-01

The atomic structures of Cu52Zr48 and Cu45Zr48Al7 metallic glasses (MGs) have been studied by molecular dynamic simulations. The results reveal that the molar volume of the Cu45Zr48Al7 MG is smaller than that of the Cu52Zr48 MG, although the size of the Al atom is larger than that of the Cu atom, implying an enhanced atomic packing density achieved by introducing Al into the ternary MG. Bond shortening in unlike atomic pairs Zr-Al and Cu-Al is observed in the Cu45Zr48Al7 MG, which is attributed to strong interactions between Al and (Zr, Cu) atoms. Meanwhile, the atomic packing efficiency is enhanced by the minor addition of Al. Compared with the Cu52Zr48 binary MG, the potential energy of the ternary MG decreases and the glass transition temperature increases. Structural analyses indicate that more Cu- and Al-centered full icosahedral clusters emerge in the Cu45Zr48Al7 MG as some Cu atoms are substituted by Al. Furthermore, the addition of Al leads to more icosahedral medium-range orders in the ternary MG. The increase of full icosahedral clusters and the enhancement of the packing density are responsible for the improved glass-forming ability of Cu45Zr48Al7.

An Expert System for Developing a Full Scale Development Statement of Work

DTIC Science & Technology

1989-09-01

Transportability: 3.5.1.3* Specialty Engineering System Safety: Aerospace Meteorlogical Environment: Preservation, Packaging, and Packing... METEORLOGICAL ENVIRONMENT:’,tn). area is ’AEROSPACE METEORLOGICAL ENVIRONMENT’ ASK ( ’The system will require operation, non-operation, transport, and/or

Dual door entry to exciplex emission in a chimeric DNA duplex containing non-nucleoside-nucleoside pair.

PubMed

Bag, Subhendu Sekhar; Talukdar, Sangita; Kundu, Rajen; Saito, Isao; Jana, Subhashis

2014-01-25

Dual door entry to exciplex formation was established in a chimeric DNA duplex wherein a fluorescent non-nucleosidic base surrogate () is paired against a fluorescent nucleosidic base surrogate (). Packing of the nucleobases via intercalative stacking interactions led to an exciplex emission either via FRET from the donor or direct excitation of the FRET acceptor .

A flow-based synthesis of imatinib: the API of Gleevec.

PubMed

Hopkin, Mark D; Baxendale, Ian R; Ley, Steven V

2010-04-14

A concise, flow-based synthesis of Imatinib, a compound used for the treatment of chronic myeloid leukaemia, is described whereby all steps are conducted in tubular flow coils or cartridges packed with reagents or scavengers to effect clean product formation. An in-line solvent switching procedure was developed enabling the procedure to be performed with limited manual handling of intermediates.

Binary dislocation junction formation and strength in hexagonal close-packed crystals

DOE PAGES

Wu, Chi -Chin; Aubry, Sylvie; Arsenlis, Athanasios; ...

2015-12-17

This work examines binary dislocation interactions, junction formation and junction strengths in hexagonal close-packed ( hcp ) crystals. Through a line-tension model and dislocation dynamics (DD) simulations, the interaction and dissociation of different sets of binary junctions are investigated involving one dislocation on the (011¯0) prismatic plane and a second dislocation on one of the following planes: (0001) basal, (11¯00) prismatic, (11¯01) primary pyramidal, or (2¯112) secondary pyramidal. Varying pairs of Burgers vectors are chosen from among the common types the basal type < a > 1/3 < 112¯0 >, prismatic type < c > <0001>, and pyramidal type 1/3 < 112¯3¯ >. For binary interaction due to dislocation intersection, both the analytical results and DD-simulations indicate a relationship between symmetry of interaction maps and the relative magnitude of the Burgers vectors that constitute the junction. Using analytical formulae, a simple regressive model is also developed to represent the junction yield surface. The equation is treated as a degenerated super elliptical equation to quantify the aspect ratio and tilting angle. Lastly, the results provide analytical insights on binary dislocation interactions that may occur in general hcp metals.« less

The Effect of Petrographic Characteristics on Engineering Properties of Conglomerates from Famenin Region, Northeast of Hamedan, Iran

NASA Astrophysics Data System (ADS)

Khanlari, G. R.; Heidari, M.; Noori, M.; Momeni, A.

2016-07-01

To assess relationship between engineering characteristics and petrographic features, conglomerates samples related to Qom formation from Famenin region in northeast of Hamedan province were studied. Samples were tested in laboratory to determine the uniaxial compressive strength, point load strength index, modulus of elasticity, porosity, dry and saturation densities. For determining petrographic features, textural and mineralogical parameters, thin sections of the samples were prepared and studied. The results show that the effect of textural characteristics on the engineering properties of conglomerates supposed to be more important than mineralogical composition. It also was concluded that the packing proximity, packing density, grain shape and mean grain size, cement and matrix frequency are as textural features that have a significant effect on the physical and mechanical properties of the studied conglomerates. In this study, predictive statistical relationships were developed to estimate the physical and mechanical properties of the rocks based on the results of petrographic features. Furthermore, multivariate linear regression was used in four different steps comprising various combinations of petrographical characteristics for each engineering parameters. Finally, the best equations with specific arrangement were suggested to estimate engineering properties of the Qom formation conglomerates.

Spin-resolved band structure of a densely packed Pb monolayer on Si(111)

NASA Astrophysics Data System (ADS)

Brand, C.; Muff, S.; Fanciulli, M.; Pfnür, H.; Tringides, M. C.; Dil, J. H.; Tegenkamp, C.

2017-07-01

Monolayer structures of Pb on Si(111) attracted recently considerable interest as superconductivity was found in these truly two-dimensional (2D) structures. In this study, we analyzed the electronic surface band structure of the so-called striped incommensurate Pb phase with 4/3 ML coverage by means of spin-resolved photoemission spectroscopy. Our results fully agree with density functional theory calculations done by Ren et al. [Phys. Rev. B 94, 075436 (2016), 10.1103/PhysRevB.94.075436]. We observe a local Zeeman-type splitting of a fully occupied and spin-polarized surface band at the K¯√{3} points. The growth of this densely packed Pb structure results in the formation of imbalanced rotational domains, which triggered the detection of C3 v symmetry forbidden spin components for surface states around the Fermi energy. Moreover, the Fermi surface of the metallic surface state of this phase is Rashba spin split and revealed a pronounced warping. However, the 2D nesting vectors are incommensurate with the atomic structure, thus keeping this system rather immune against charge density wave formation and possibly enabling a superconducting behavior.

Three-Dimensional Printing of Hollow-Struts-Packed Bioceramic Scaffolds for Bone Regeneration.

PubMed

Luo, Yongxiang; Zhai, Dong; Huan, Zhiguang; Zhu, Haibo; Xia, Lunguo; Chang, Jiang; Wu, Chengtie

2015-11-04

Three-dimensional printing technologies have shown distinct advantages to create porous scaffolds with designed macropores for application in bone tissue engineering. However, until now, 3D-printed bioceramic scaffolds only possessing a single type of macropore have been reported. Generally, those scaffolds with a single type of macropore have relatively low porosity and pore surfaces, limited delivery of oxygen and nutrition to surviving cells, and new bone tissue formation in the center of the scaffolds. Therefore, in this work, we present a useful and facile method for preparing hollow-struts-packed (HSP) bioceramic scaffolds with designed macropores and multioriented hollow channels via a modified coaxial 3D printing strategy. The prepared HSP scaffolds combined high porosity and surface area with impressive mechanical strength. The unique hollow-struts structures of bioceramic scaffolds significantly improved cell attachment and proliferation and further promoted formation of new bone tissue in the center of the scaffolds, indicating that HSP ceramic scaffolds can be used for regeneration of large bone defects. In addition, the strategy can be used to prepare other HSP ceramic scaffolds, indicating a universal application for tissue engineering, mechanical engineering, catalysis, and environmental materials.

Three-phase fracturing in granular material

NASA Astrophysics Data System (ADS)

Campbell, James; Sandnes, Bjornar

2015-04-01

There exist numerous geo-engineering scenarios involving the invasion of a gas into a water-saturated porous medium: in fracking, this may occur during the fracking process itself or during subsequent gas penetration into propant beds; the process is also at the heart of carbon dioxide sequestration. We use a bed of water-saturated glass beads confined within a Hele-Shaw cell as a model system to illuminate these processes. Depending on packing density, injection rate and other factors, air injected into this system may invade in a broad variety of patterns, including viscous fingering, capillary invasion, bubble formation and fracturing. Here we focus primarily on the latter case. Fracturing is observed when air is injected into a loosely packed bed of unconsolidated granular material. Our approach allows us to image the complete fracture pattern as it forms, and as such to study both the topographical properties of the resulting pattern (fracture density, braching frequency etc) and the dynamics of its growth. We present an overview of the fracturing phenomenon within the context of pattern formation in granular fluids as a whole. We discuss how fracturing arises from an interplay between frictional, capillary and viscous forces, and demonstrate the influence of various parameters on the result.

Automated selection of stabilizing mutations in designed and natural proteins.

PubMed

Borgo, Benjamin; Havranek, James J

2012-01-31

The ability to engineer novel protein folds, conformations, and enzymatic activities offers enormous potential for the development of new protein therapeutics and biocatalysts. However, many de novo and redesigned proteins exhibit poor hydrophobic packing in their predicted structures, leading to instability or insolubility. The general utility of rational, structure-based design would greatly benefit from an improved ability to generate well-packed conformations. Here we present an automated protocol within the RosettaDesign framework that can identify and improve poorly packed protein cores by selecting a series of stabilizing point mutations. We apply our method to previously characterized designed proteins that exhibited a decrease in stability after a full computational redesign. We further demonstrate the ability of our method to improve the thermostability of a well-behaved native protein. In each instance, biophysical characterization reveals that we were able to stabilize the original proteins against chemical and thermal denaturation. We believe our method will be a valuable tool for both improving upon designed proteins and conferring increased stability upon native proteins.

Automated selection of stabilizing mutations in designed and natural proteins

PubMed Central

Borgo, Benjamin; Havranek, James J.

2012-01-01

The ability to engineer novel protein folds, conformations, and enzymatic activities offers enormous potential for the development of new protein therapeutics and biocatalysts. However, many de novo and redesigned proteins exhibit poor hydrophobic packing in their predicted structures, leading to instability or insolubility. The general utility of rational, structure-based design would greatly benefit from an improved ability to generate well-packed conformations. Here we present an automated protocol within the RosettaDesign framework that can identify and improve poorly packed protein cores by selecting a series of stabilizing point mutations. We apply our method to previously characterized designed proteins that exhibited a decrease in stability after a full computational redesign. We further demonstrate the ability of our method to improve the thermostability of a well-behaved native protein. In each instance, biophysical characterization reveals that we were able to stabilize the original proteins against chemical and thermal denaturation. We believe our method will be a valuable tool for both improving upon designed proteins and conferring increased stability upon native proteins. PMID:22307603

Molybdeno-Aluminizing of Powder Metallurgy and Wrought Ti and Ti-6Al-4V alloys by Pack Cementation process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsipas, Sophia A., E-mail: stsipas@ing.uc3m.es; Go

Wear and high temperature oxidation resistance of some titanium-based alloys needs to be enhanced, and this can be effectively accomplished by surface treatment. Molybdenizing is a surface treatment where molybdenum is introduced into the surface of titanium alloys causing the formation of wear-resistant surface layers containing molybdenum, while aluminizing of titanium-based alloys has been reported to improve their high temperature oxidation properties. Whereas pack cementation and other surface modification methods have been used for molybdenizing or aluminizing of wrought and/or cast pure titanium and titanium alloys, such surface treatments have not been reported on titanium alloys produced by powder metallurgymore » (PM). Also a critical understanding of the process parameters for simultaneous one step molybdeno-aluminizing of titanium alloys by pack cementation and the predominant mechanism for this process have not been reported. The current research work describes the surface modification of titanium and Ti-6Al-4V prepared by PM by molybdeno-aluminizing and analyzes thermodynamic aspects of the deposition process. Similar coatings are also deposited to wrought Ti-6Al-4V and compared. Characterization of the coatings was carried out using scanning electron microscopy and x-ray diffraction. For both titanium and Ti-6Al-4V, the use of a powder pack containing ammonium chloride as activator leads to the deposition of molybdenum and aluminium into the surface but also introduces nitrogen causing the formation of a thin titanium nitride layer. In addition, various titanium aluminides and mixed titanium aluminium nitrides are formed. The appropriate conditions for molybdeno-aluminizing as well as the phases expected to be formed were successfully determined by thermodynamic equilibrium calculations. - Highlights: •Simultaneous co-deposition of Mo-Al onto powder metallurgy and wrought Ti alloy •Thermodynamic calculations were used to optimize deposition conditions •External TiN and internal a Mo-rich layer on all alloy substrates •Titanium aluminides and Ti-Al mixed nitrides are formed on Ti-6Al-4V •The presence of Al and V alloying elements modifies the diffusion of Mo.« less

Quality of comminuted sausages formulated from mechanically deboned poultry meat.

PubMed

Mielnik, Maria B; Aaby, Kjersti; Rolfsen, Knut; Ellekjær, Marit R; Nilsson, Astrid

2002-05-01

Comminuted sausages formulated with mechanically deboned poultry meat-MDPM (turkey or chicken, frame or neck) treated in different ways before production (vacuum packed MDPM or air packed skeletons deboned at production) and stored frozen for 6 or 18 weeks have been studied using a full-factorial design and chemical, physical and sensory analysis. MDPM was obtained from a Beehive separator. Comminuted sausages with MDPM from turkey frames, stored at -25 °C as skeletons, packed in air for 18 weeks developed marked rancid odour and flavour which could also be detected by thiobarbituric acid reactive substances (TBARS) and the concentration of volatile compounds. Vacuum packed mechanically deboned meat irrespective of species and carcass part could be stored for up to 18 weeks and used in formulation of sausages without any serious changes in their sensory profiles. Instrumental colour differences between sausages were mainly due to species. Turkey sausages were darker, redder and less yellow than chicken sausages. Moisture and fat contents were influenced by carcass part and to a lesser extent depended on species and storage time. Principal least squares regression (PLS2) showed close relationships between instrumental parameters and sensory attributes. TBARS, hexanal and volatile compounds were highly correlated with rancid flavour while redness (a(∗)) was strongly related to sensory colour hue and colour strength.

A case-controlled, retrospective, comparative study on the use of biodegradable synthetic polyurethane foam versus polyvinyl acetate sponge after nasal fracture reduction.

PubMed

Jeong, H-S; Lee, H-K; Kim, H-S; Moon, M-S; Tark, K-C

2014-06-01

One of the most frequently used packing materials in closed reduction of a nasal bone fracture is the hydroxylated polyvinyl acetate sponge (PVAS; Merocel(®)); however this may cause synechia, epistaxis, and pain. Synthetic polyurethane foam (SPF; Nasopore(®) Forte) has recently been used in septoplasty to prevent synechia or restenosis and haematoma formation. The purpose of this study was to compare the effects of PVAS and SPF on postoperative appearance and discomfort following the reduction of nasal bone fractures. We retrospectively reviewed all patient questionnaires and medical histories, and clinical photographs and computed tomography scans obtained before and after surgery. Outcomes were assessed using the Global Aesthetic Improvement Scale (GAIS) score and visual analogue scale (VAS) scores, which were used to assess discomfort during the 6-month follow-up period. Postoperatively, there was no statistically significant difference in the GAIS for the two packing materials (P > 0.05). Postoperative epistaxis was observed at a significantly lower rate in the SPF group than in the PVAS group, whereas anterior rhinorrhea and posterior nasal drip occurred at significantly higher rates following removal of packing in the SPF group (P < 0.05). The results of this study suggest that synthetic dissolvable polyurethane may be a reliable alternative material for nasal packing and postoperative management following the reduction of nasal bone fractures. Copyright © 2014 International Association of Oral and Maxillofacial Surgeons. Published by Elsevier Ltd. All rights reserved.

Evaluation of advanced silica packings for the separation of biopolymers by high-performance liquid chromatography. VI. Design, chromatographic performance and application of non-porous silica-based anion exchangers.

PubMed

Jilge, G; Unger, K K; Esser, U; Schäfer, H J; Rathgeber, G; Müller, W

1989-08-04

The linear solvent strength model of Snyder was applied to describe fast protein separations on 2.1-micron non-porous, silica-based strong anion exchangers. It was demonstrated on short columns packed with these anion exchangers that (i) a substantially higher resolution of proteins and nucleotides was obtained at gradient times of less than 5 min than on porous anion exchangers; (ii) the low external surface area of the non-porous anion exchanger is not a critical parameter in analytical separations and (iii) microgram-amounts of enzymes of high purity and full biological activity were isolated.

Square-core bundles for astronomical imaging

NASA Astrophysics Data System (ADS)

Bryant, Julia J.; Bland-Hawthorn, Joss

2012-09-01

Optical fibre imaging bundles (hexabundles) are proving to be the next logical step for large galaxy surveys as they offer spatially-resolved spectroscopy of galaxies and can be used with conventional fibre positioners. Hexabundles have been effectively demonstrated in the Sydney-AAO Multi-object IFS (SAMI) instrument at the Anglo- Australian Telescope[5]. Based on the success of hexabundles that have circular cores, we have characterised a bundle made instead from square-core fibres. Square cores naturally pack more evenly, which reduces the interstitial holes and can increase the covering, or filling fraction. Furthermore the regular packing simplifies the process of combining and dithering the final images. We discuss the relative issues of filling fraction, focal ratio degradation (FRD), and cross-talk, and find that square-core bundles perform well enough to warrant further development as a format for imaging fibre bundles.

Engineering solid-state materials. Strategies for modeling and packing control of molecular assemblies into 3-D networks

NASA Astrophysics Data System (ADS)

Videnova-Adrabinska, V.; Etter, M. C.; Ward, M. D.

1993-04-01

The crystal structure and properties of a number of urea cocrystals are studied with regard to symmetry of the hydrogen-bonded molecular assemblies. The logical consequences of hydrogen bonding interactions are followed step-by-step. The problems of aggregate formation, nucleation, and crystal growth are also elucidated. Endeavor is made to envisage the 2-D and 3-D hydrogen bond network in a manageable way by exploiting graph set short hand. Strategies of how to control the symmetry of molecular packing are still to be elaborated. In our strategy, the programmed self-assembly has been based on the principle of molecular recognition of self- and hetero-complementary functional groups. However, the main focus for pre-organizational control has been put on the two-fold axis estimator of the urea molecule.

Discovery of a Frank-Kasper [sigma] Phase in Sphere-Forming Block Copolymer Melts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Sangwoo; Bluemle, Michael J.; Bates, Frank S.

Sphere-forming block copolymers are known to self-assemble into body-centered cubic crystals near the order-disorder transition temperature. Small-angle x-ray scattering and transmission electron microscopy experiments on diblock and tetrablock copolymer melts have revealed an equilibrium phase characterized by a large tetragonal unit cell containing 30 microphase-separated spheres. This structure, referred to as the sigma ({sigma}) phase by Frank and Kasper more than 50 years ago, nucleates and grows from the body-centered cubic phase similar to its occurrence in metal alloys and is a crystal approximant to dodecagonal quasicrystals. Formation of the {sigma} phase in undiluted linear block copolymers (and certain branchedmore » dendrimers) appears to be mediated by macromolecular packing frustration, an entropic contribution to the interparticle interactions that control the sphere-packing geometry.« less

Dense granular flow around a rigid or flexible intruder

NASA Astrophysics Data System (ADS)

Kolb, Evelyne; Adda-Bedia, Mokhtar

2012-02-01

We experimentally studied the flow of a dense granular material around an obstacle (rigid cylinder or flexible plate) placed in a 2 dimensional confined cell at a packing fraction near the 2D jamming threshold. In the case of the rigid obstacle, the displacement field of grains as well as the drag force experienced by the obstacle were simultaneously recorded and a parametric study was done by changing the cell size, the intruder diameter or the packing fraction. The drag force experienced by the intruder and the formation of a wake behind the obstacle were very sensitive to the approach to jamming. The same experimental set-up was adapted to a flexible intruder and coupling between the granular flow and fibre deflexion were imaged. The deformation of the fibre could be compared with theoretical predictions from elastica.

Dislocation dynamics in hexagonal close-packed crystals

DOE PAGES

Aubry, S.; Rhee, M.; Hommes, G.; ...

2016-04-14

Extensions of the dislocation dynamics methodology necessary to enable accurate simulations of crystal plasticity in hexagonal close-packed (HCP) metals are presented. They concern the introduction of dislocation motion in HCP crystals through linear and non-linear mobility laws, as well as the treatment of composite dislocation physics. Formation, stability and dissociation of and other dislocations with large Burgers vectors defined as composite dislocations are examined and a new topological operation is proposed to enable their dissociation. Furthermore, the results of our simulations suggest that composite dislocations are omnipresent and may play important roles both in specific dislocation mechanisms and in bulkmore » crystal plasticity in HCP materials. While fully microscopic, our bulk DD simulations provide wealth of data that can be used to develop and parameterize constitutive models of crystal plasticity at the mesoscale.« less

Analysis of microstructure-dependent shock dissipation and hot-spot formation in granular metalized explosive

NASA Astrophysics Data System (ADS)

Chakravarthy, Sunada; Gonthier, Keith A.

2016-07-01

Variations in the microstructure of granular explosives (i.e., particle packing density, size, shape, and composition) can affect their shock sensitivity by altering thermomechanical fields at the particle-scale during pore collapse within shocks. If the deformation rate is fast, hot-spots can form, ignite, and interact, resulting in burn at the macro-scale. In this study, a two-dimensional finite and discrete element technique is used to simulate and examine shock-induced dissipation and hot-spot formation within low density explosives (68%-84% theoretical maximum density (TMD)) consisting of large ensembles of HMX (C4H8N8O8) and aluminum (Al) particles (size ˜ 60 -360 μm). Emphasis is placed on identifying how the inclusion of Al influences effective shock dissipation and hot-spot fields relative to equivalent ensembles of neat/pure HMX for shocks that are sufficiently strong to eliminate porosity. Spatially distributed hot-spot fields are characterized by their number density and area fraction enabling their dynamics to be described in terms of nucleation, growth, and agglomeration-dominated phases with increasing shock strength. For fixed shock particle speed, predictions indicate that decreasing packing density enhances shock dissipation and hot-spot formation, and that the inclusion of Al increases dissipation relative to neat HMX by pressure enhanced compaction resulting in fewer but larger HMX hot-spots. Ensembles having bimodal particle sizes are shown to significantly affect hot-spot dynamics by altering the spatial distribution of hot-spots behind shocks.

Bacterial Standing Stock, Activity, and Carbon Production during Formation and Growth of Sea Ice in the Weddell Sea, Antarctica.

PubMed

Grossmann, S; Dieckmann, G S

1994-08-01

Bacterial response to formation and growth of sea ice was investigated during autumn in the northeastern Weddell Sea. Changes in standing stock, activity, and carbon production of bacteria were determined in successive stages of ice development. During initial ice formation, concentrations of bacterial cells, in the order of 1 x 10 to 3 x 10 liter, were not enhanced within the ice matrix. This suggests that physical enrichment of bacteria by ice crystals is not effective. Due to low concentrations of phytoplankton in the water column during freezing, incorporation of bacteria into newly formed ice via attachment to algal cells or aggregates was not recorded in this study. As soon as the ice had formed, the general metabolic activity of bacterial populations was strongly suppressed. Furthermore, the ratio of [H]leucine incorporation into proteins to [H]thymidine incorporation into DNA changed during ice growth. In thick pack ice, bacterial activity recovered and growth rates up to 0.6 day indicated actively dividing populations. However, biomass-specific utilization of organic compounds remained lower than in open water. Bacterial concentrations of up to 2.8 x 10 cells liter along with considerably enlarged cell volumes accumulated within thick pack ice, suggesting reduced mortality rates of bacteria within the small brine pores. In the course of ice development, bacterial carbon production increased from about 0.01 to 0.4 mug of C liter h. In thick ice, bacterial secondary production exceeded primary production of microalgae.

Long conducting polymer nanonecklaces with a `beads-on-a-string' morphology: DNA nanotube-template synthesis and electrical properties

NASA Astrophysics Data System (ADS)

Chen, Guofang; Mao, Chengde

2016-05-01

Complex and functional nanostructures are always desired. Herein, we present the synthesis of novel long conducting polymer nanonecklaces with a `beads-on-a-string' morphology by the DNA nanotube-template approach and in situ oxidative polymerization of the 3-methylthiophene monomer with FeCl3 as the oxidant/catalyst. The length of the nanonecklaces is up to 60 μm, and the polymer beads of around 20-25 nm in diameter are closely packed along the axis of the DNA nanotube template with a density of ca. 45 particles per μm. The formation of porous DNA nanotubes impregnated with FeCl3 was also demonstrated as intermediate nanostructures. The mechanisms for the formation of both the porous DNA nanotubes and the conducting polymer nanonecklaces are discussed in detail. The as-synthesized polymer/DNA nanonecklaces exhibit good electrical properties.Complex and functional nanostructures are always desired. Herein, we present the synthesis of novel long conducting polymer nanonecklaces with a `beads-on-a-string' morphology by the DNA nanotube-template approach and in situ oxidative polymerization of the 3-methylthiophene monomer with FeCl3 as the oxidant/catalyst. The length of the nanonecklaces is up to 60 μm, and the polymer beads of around 20-25 nm in diameter are closely packed along the axis of the DNA nanotube template with a density of ca. 45 particles per μm. The formation of porous DNA nanotubes impregnated with FeCl3 was also demonstrated as intermediate nanostructures. The mechanisms for the formation of both the porous DNA nanotubes and the conducting polymer nanonecklaces are discussed in detail. The as-synthesized polymer/DNA nanonecklaces exhibit good electrical properties. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01603k

PlanetPack: A radial-velocity time-series analysis tool facilitating exoplanets detection, characterization, and dynamical simulations

NASA Astrophysics Data System (ADS)

Baluev, Roman V.

2013-08-01

We present PlanetPack, a new software tool that we developed to facilitate and standardize the advanced analysis of radial velocity (RV) data for the goal of exoplanets detection, characterization, and basic dynamical N-body simulations. PlanetPack is a command-line interpreter, that can run either in an interactive mode or in a batch mode of automatic script interpretation. Its major abilities include: (i) advanced RV curve fitting with the proper maximum-likelihood treatment of unknown RV jitter; (ii) user-friendly multi-Keplerian as well as Newtonian N-body RV fits; (iii) use of more efficient maximum-likelihood periodograms that involve the full multi-planet fitting (sometimes called as “residual” or “recursive” periodograms); (iv) easily calculatable parametric 2D likelihood function level contours, reflecting the asymptotic confidence regions; (v) fitting under some useful functional constraints is user-friendly; (vi) basic tasks of short- and long-term planetary dynamical simulation using a fast Everhart-type integrator based on Gauss-Legendre spacings; (vii) fitting the data with red noise (auto-correlated errors); (viii) various analytical and numerical methods for the tasks of determining the statistical significance. It is planned that further functionality may be added to PlanetPack in the future. During the development of this software, a lot of effort was made to improve the calculational speed, especially for CPU-demanding tasks. PlanetPack was written in pure C++ (standard of 1998/2003), and is expected to be compilable and useable on a wide range of platforms.

Virtual and Experimental Visualization of Flows in Packed Beds of Spheres Simulating Porous Media Flows

NASA Technical Reports Server (NTRS)

Hendricks, R. C.; Athavale, M. M.; Lattime, S. B.; Braun, M. J.

1998-01-01

A videotape presentation of flow in a packed bed of spheres is provided. The flow experiment consisted of three principal elements: (1) an oil tunnel 76.2 mm by 76.2 mm in cross section, (2) a packed bed of spheres in regular and irregular arrays, and (3) a flow characterization methodology, either (a) full flow field tracking (FFFT) or (b) computational fluid dynamic (CFD) simulation. The refraction indices of the oil and the test array of spheres were closely matched, and the flow was seeded with aluminum oxide particles. Planar laser light provided a two-dimensional projection of the flow field, and a traverse simulated a three-dimensional image of the entire flow field. Light focusing and reflection rendered the spheres black, permitting visualization of the planar circular interfaces in both the axial and transverse directions. Flows were observed near the wall-sphere interface and within the set of spheres. The CFD model required that a representative section of a packed bed be formed and gridded, enclosing and cutting six spheres so that symmetry conditions could be imposed at all cross-boundaries. Simulations had to be made with the flow direction at right angles to that used in the experiments, however, to take advantage of flow symmetry. Careful attention to detail was required for proper gridding. The flow field was three-dimensional and complex to describe, yet the most prominent finding was flow threads, as computed in the representative 'cube' of spheres with face symmetry and conclusively demonstrated experimentally herein. Random packing and bed voids tended to disrupt the laminar flow, creating vortices.

Public attitudes toward larger cigarette pack warnings: Results from a nationally representative U.S. sample

PubMed Central

2017-01-01

A large body of evidence supports the effectiveness of larger health warnings on cigarette packages. However, there is limited research examining attitudes toward such warning labels, which has potential implications for implementation of larger warning labels. The purpose of the current study was to examine attitudes toward larger warning sizes on cigarette packages and examine variables associated with more favorable attitudes. In a nationally representative survey of U.S. adults (N = 5,014), participants were randomized to different warning size conditions, assessing attitude toward “a health warning that covered (25, 50, 75) % of a cigarette pack.” SAS logistic regression survey procedures were used to account for the complex survey design and sampling weights. Across experimental groups, nearly three-quarters (72%) of adults had attitudes supportive of larger warning labels on cigarette packs. Among the full sample and smokers only (N = 1,511), most adults had favorable attitudes toward labels that covered 25% (78.2% and 75.2%, respectively), 50% (70% and 58.4%, respectively), and 75% (67.9% and 61%, respectively) of a cigarette pack. Young adults, females, racial/ethnic minorities, and non-smokers were more likely to have favorable attitudes toward larger warning sizes. Among smokers only, females and those with higher quit intentions held more favorable attitudes toward larger warning sizes. Widespread support exists for larger warning labels on cigarette packages among U.S. adults, including among smokers. Our findings support the implementation of larger health warnings on cigarette packs in the U.S. as required by the 2009 Tobacco Control Act. PMID:28253257

Influence of ice and snow covers on the UV exposure of terrestrial microbial communities: dosimetric studies.

PubMed

Cockell, Charles S; Rettberg, Petra; Horneck, Gerda; Wynn-Williams, David D; Scherer, Kerstin; Gugg-Helminger, Anton

2002-08-01

Bacillus subtilis spore biological dosimeters and electronic dosimeters were used to investigate the exposure of terrestrial microbial communities in micro-habitats covered by snow and ice in Antarctica. The melting of snow covers of between 5- and 15-cm thickness, depending on age and heterogeneity, could increase B. subtilis spore inactivation by up to an order of magnitude, a relative increase twice that caused by a 50% ozone depletion. Within the snow-pack at depths of less than approximately 3 cm snow algae could receive two to three times the DNA-weighted irradiance they would receive on bare ground. At the edge of the snow-pack, warming of low albedo soils resulted in the formation of overhangs that provided transient UV protection to thawed and growing microbial communities on the soils underneath. In shallow aquatic habitats, thin layers of heterogeneous ice of a few millimetres thickness were found to reduce DNA-weighted irradiances by up to 55% compared to full-sky values with equivalent DNA-weighted diffuse attenuation coefficients (K(DNA)) of >200 m(-1). A 2-mm snow-encrusted ice cover on a pond was equivalent to 10 cm of ice on a perennially ice covered lake. Ice covers also had the effect of stabilizing the UV exposure, which was often subject to rapid variations of up to 33% of the mean value caused by wind-rippling of the water surface. These data show that changing ice and snow covers cause relative changes in microbial UV exposure at least as great as those caused by changing ozone column abundance. Copyright 2002 Elsevier Science B.V.

Bit Grooming: statistically accurate precision-preserving quantization with compression, evaluated in the netCDF Operators (NCO, v4.4.8+)

NASA Astrophysics Data System (ADS)

Zender, Charles S.

2016-09-01

Geoscientific models and measurements generate false precision (scientifically meaningless data bits) that wastes storage space. False precision can mislead (by implying noise is signal) and be scientifically pointless, especially for measurements. By contrast, lossy compression can be both economical (save space) and heuristic (clarify data limitations) without compromising the scientific integrity of data. Data quantization can thus be appropriate regardless of whether space limitations are a concern. We introduce, implement, and characterize a new lossy compression scheme suitable for IEEE floating-point data. Our new Bit Grooming algorithm alternately shaves (to zero) and sets (to one) the least significant bits of consecutive values to preserve a desired precision. This is a symmetric, two-sided variant of an algorithm sometimes called Bit Shaving that quantizes values solely by zeroing bits. Our variation eliminates the artificial low bias produced by always zeroing bits, and makes Bit Grooming more suitable for arrays and multi-dimensional fields whose mean statistics are important. Bit Grooming relies on standard lossless compression to achieve the actual reduction in storage space, so we tested Bit Grooming by applying the DEFLATE compression algorithm to bit-groomed and full-precision climate data stored in netCDF3, netCDF4, HDF4, and HDF5 formats. Bit Grooming reduces the storage space required by initially uncompressed and compressed climate data by 25-80 and 5-65 %, respectively, for single-precision values (the most common case for climate data) quantized to retain 1-5 decimal digits of precision. The potential reduction is greater for double-precision datasets. When used aggressively (i.e., preserving only 1-2 digits), Bit Grooming produces storage reductions comparable to other quantization techniques such as Linear Packing. Unlike Linear Packing, whose guaranteed precision rapidly degrades within the relatively narrow dynamic range of values that it can compress, Bit Grooming guarantees the specified precision throughout the full floating-point range. Data quantization by Bit Grooming is irreversible (i.e., lossy) yet transparent, meaning that no extra processing is required by data users/readers. Hence Bit Grooming can easily reduce data storage volume without sacrificing scientific precision or imposing extra burdens on users.

Modeling and Validation of Lithium-ion Automotive Battery Packs (SAE 2013-01-1539)

EPA Science Inventory

The Advanced Light-Duty Powertrain and Hybrid Analysis (ALPHA) tool was created by EPA to evaluate the Greenhouse Gas (GHG) emissions of Light-Duty (LD) vehicles. It is a physics-based, forward-looking, full vehicle computer simulator capable of analyzing various vehicle types c...

OsN2: Crystal structure and electronic properties

NASA Astrophysics Data System (ADS)

Montoya, Javier A.; Hernandez, Alexander D.; Sanloup, Chrystèle; Gregoryanz, Eugene; Scandolo, Sandro

2007-01-01

Osmium nitride belongs to a family of nitrides synthesized recently at high pressures from their parent elements. Here we show, based on first-principles calculations, that the crystal structure of osmium nitride is isostructural to marcasite. Excellent agreement is obtained between the authors' results and x-ray, Raman, and compressibility measurements. In the OsN2 marcasite structure single-bonded N2 units occupy the interstitial sites of the Os close-packed lattice, giving rise to a metallic compound. A comparison between the formation energies of OsN2 and PtN2 explains the similar thermodynamic conditions of formation reported experimentally for the two compounds.

Preparation of polystyrene/SiO2 microsphere via Pickering emulsion polymerization: Synergistic effect of SiO2 concentrations and initiator sorts

NASA Astrophysics Data System (ADS)

Zhou, Haiou; Shi, Tiejun; Zhou, Xun

2013-02-01

In this paper, polystyrene (PS)/SiO2 microspheres were successfully prepared via Pickering emulsion polymerization stabilized solely by ethacryloxypropyltrimethoxysilane (MPTMS) modified SiO2 nanoparticles. The formation mechanisms of PS/SiO2 microspheres with different morphology were investigated under various Pickering emulsion polymerization conditions. The results showed that SiO2 concentrations and initiator sorts would synergistically impact on the morphology of products corresponding to distinct formation mechanisms. When SiO2 concentrations was low and water-solute initiator potassium persulfate (KPS) was used, aqueous nucleation was dominant, which was deduced to the formation of dispersive microspheres sparsely anchored by SiO2 particles. When SiO2 concentrations was increased and oil-solute initiator azobisisobutyronitrile (AIBN) was applied, nucleation in oil phase prevailed which lead to the formation of microspheres densely packed by SiO2 particles.

Formative and Summative Assessment in Veterinary Pathology and Other Courses at a Mexican Veterinary College.

PubMed

Valero, Germán; Cárdenas, Paula

The Faculty of Veterinary Medicine and Animal Science of the National Autonomous University of Mexico (UNAM) uses the Moodle learning management system for formative and summative computer assessment. The authors of this article-the teacher primarily responsible for Moodle implementation and a researcher who is a recent Moodle adopter-describe and discuss the students' and teachers' attitudes to summative and formative computer assessment in Moodle. Item analysis of quiz results helped us to identify and fix poorly performing questions, which greatly reduced student complaints and improved objective assessment. The use of certainty-based marking (CBM) in formative assessment in veterinary pathology was well received by the students and should be extended to more courses. The importance of having proficient computer support personnel should not be underestimated. A properly translated language pack is essential for the use of Moodle in a language other than English.

Development of a sensitive and rapid method for rifampicin impurity analysis using supercritical fluid chromatography.

PubMed

Li, Wei; Wang, Jun; Yan, Zheng-Yu

2015-10-10

A novel simple, fast and efficient supercritical fluid chromatography (SFC) method was developed and compared with RPLC method for the separation and determination of impurities in rifampicin. The separation was performed using a packed diol column and a mobile phase B (modifier) consisting of methanol with 0.1% ammonium formate (w/v) and 2% water (v/v). Overall satisfactory resolutions and peak shapes for rifampicin quinone (RQ), rifampicin (RF), rifamycin SV (RSV), rifampicin N-oxide (RNO) and 3-formylrifamycinSV (3-FR) were obtained by optimization of the chromatography system. With gradient elution of mobile phase, all of the impurities and the active were separated within 4 min. Taking full advantage of features of SFC (such as particular selectivity, non-sloping baseline in gradient elution, and without injection solvent effects), the method was successfully used for determination of impurities in rifampicin, with more impurity peaks detected, better resolution achieved and much less analysis time needed compared with conventional reversed-phase liquid chromatography (RPLC) methods. Copyright © 2015 Elsevier B.V. All rights reserved.

Design it yourself (DIY): in-house instructional design for online pharmacology.

PubMed

Loftus, Jay; Stavraky, Tom; Urquhart, Bradley L

2014-12-01

Demand for e-learning courses has risen dramatically placing pressure on institutions to offer more online courses. Third party vendors now offer courses that can be embedded directly into learning management systems. When transitioning from in-class to e-learning formats, instructors must decide whether to use commercially available courses or design in-house. The objective of this study was to evaluate our transition from delivering introductory pharmacology via a purchased e-pack to an in-house designed course. A team that included an instructional designer, an education specialist and a content expert created an online course in pharmacology. Merrill's first principles of instruction were used as a guide for the design of our online course. Where appropriate, multiple forms of media were introduced to reinforce concepts. We compared grades and design strategy from a previous iteration that was delivered using a commercially available e-pack. A cost analysis was conducted to determine the institutional setup and maintenance costs of in-house course design. The mean final grade from the in-house designed course was 81.9 (0.5) % compared to 76.4 (0.5) % for the e-pack course (P < 0.001). Course evaluations were significantly improved for the in-house course compared to the e-pack. Cost-analysis demonstrated that designing a course in-house has a high initial cost ($111,180.57) but can be maintained with minimal institutional cost ($500) in future offerings. Our results demonstrate that effective courses can be designed in-house and this should be a viable option for institutions that have appropriate resources to support instructional design.

Technological and life cycle assessment of organics processing odour control technologies.

PubMed

Bindra, Navin; Dubey, Brajesh; Dutta, Animesh

2015-09-15

As more municipalities and communities across developed world look towards implementing organic waste management programmes or upgrading existing ones, composting facilities are emerging as a popular choice. However, odour from these facilities continues to be one of the most important concerns in terms of cost & effective mitigation. This paper provides a technological and life cycle assessment of some of the different odour control technologies and treatment methods that can be implemented in organics processing facilities. The technological assessment compared biofilters, packed tower wet scrubbers, fine mist wet scrubbers, activated carbon adsorption, thermal oxidization, oxidization chemicals and masking agents. The technologies/treatment methods were evaluated and compared based on a variety of operational, usage and cost parameters. Based on the technological assessment it was found that, biofilters and packed bed wet scrubbers are the most applicable odour control technologies for use in organics processing faculties. A life cycle assessment was then done to compare the environmental impacts of the packed-bed wet scrubber system, organic (wood-chip media) bio-filter and inorganic (synthetic media) bio-filter systems. Twelve impact categories were assessed; cumulative energy demand (CED), climate change, human toxicity, photochemical oxidant formation, metal depletion, fossil depletion, terrestrial acidification, freshwater eutrophication, marine eutrophication, terrestrial eco-toxicity, freshwater eco-toxicity and marine eco-toxicity. The results showed that for all impact categories the synthetic media biofilter had the highest environmental impact, followed by the wood chip media bio-filter system. The packed-bed system had the lowest environmental impact for all categories. Copyright © 2015 Elsevier B.V. All rights reserved.

Factors determining the average atomic volumes in intermetallic compounds.

PubMed

Pauling, L

1987-07-01

In formation of an intermetallic compound from the elementary metals there is usually a contraction in volume. Electron transfer leading to the charge states M(+) and M(-) with increase in valence and decrease in volume explains the more than 2-fold range in contraction for different compounds in the same binary system. In a more thorough analysis, the better packing of atoms of different sizes also needs to be considered.

Lab-on-a-Chip Sensor for Monitoring Perchlorate in Ground and Surface Water

DTIC Science & Technology

2012-02-01

uses zwitterionic surfactants was immobilized on either a conventional or membrane-based stationary phase (electrostatic ion chromatography ) em...substantially higher than that of drinking water. A novel extraction method incorporat- ing the fundamentals of electrostatic ion chromatography (EIC) was...electrostatic ion chromatography (EIC), is presented as a way to overcome this challenge. Two extraction formats, employing either a packed bed or a monolith

Predicting Instability Timescales in Closely-Packed Planetary Systems

NASA Astrophysics Data System (ADS)

Tamayo, Daniel; Hadden, Samuel; Hussain, Naireen; Silburt, Ari; Gilbertson, Christian; Rein, Hanno; Menou, Kristen

2018-04-01

Many of the multi-planet systems discovered around other stars are maximally packed. This implies that simulations with masses or orbital parameters too far from the actual values will destabilize on short timescales; thus, long-term dynamics allows one to constrain the orbital architectures of many closely packed multi-planet systems. A central challenge in such efforts is the large computational cost of N-body simulations, which preclude a full survey of the high-dimensional parameter space of orbital architectures allowed by observations. I will present our recent successes in training machine learning models capable of reliably predicting orbital stability a million times faster than N-body simulations. By engineering dynamically relevant features that we feed to a gradient-boosted decision tree algorithm (XGBoost), we are able to achieve a precision and recall of 90% on a holdout test set of N-body simulations. This opens a wide discovery space for characterizing new exoplanet discoveries and for elucidating how orbital architectures evolve through time as the next generation of spaceborne exoplanet surveys prepare for launch this year.

Self-Assembled Layering of Magnetic Nanoparticles in a Ferrofluid on Silicon Surfaces.

PubMed

Theis-Bröhl, Katharina; Vreeland, Erika C; Gomez, Andrew; Huber, Dale L; Saini, Apurve; Wolff, Max; Maranville, Brian B; Brok, Erik; Krycka, Kathryn L; Dura, Joseph A; Borchers, Julie A

2018-02-07

This article describes the three-dimensional self-assembly of monodisperse colloidal magnetite nanoparticles (NPs) from a dilute water-based ferrofluid onto a silicon surface and the dependence of the resultant magnetic structure on the applied field. The NPs assemble into close-packed layers on the surface followed by more loosely packed ones. The magnetic field-dependent magnetization of the individual NP layers depends on both the rotational freedom of the layer and the magnetization of the adjacent layers. For layers in which the NPs are more free to rotate, the easy axis of the NP can readily orient along the field direction. In more dense packing, free rotation of the NPs is hampered, and the NP ensembles likely build up quasi-domain states to minimize energy, which leads to lower magnetization in those layers. Detailed analysis of polarized neutron reflectometry data together with model calculations of the arrangement of the NPs within the layers and input from small-angle scattering measurements provide full characterization of the core/shell NP dimensions, degree of chaining, arrangement of the NPs within the different layers, and magnetization depth profile.

Occurrence of furan in coffee from Spanish market: Contribution of brewing and roasting.

PubMed

Altaki, M S; Santos, F J; Galceran, M T

2011-06-15

In this work, we evaluated the occurrence of furan in brews obtained from regular, decaffeinated, and instant coffee and commercial packed capsules. For this purpose, a previously developed automated headspace solid-phase microextraction method coupled to gas chromatography-mass spectrometry (HS-SPME-GC-MS) was used. Initially, the influence of HS-SPME conditions on furan formation was evaluated. In addition, the effect of roasting conditions (temperature and time) used for coffee beans on furan formation was also studied. We found that low temperature and long roasting time (140°C and 20min) decreases the final furan content. Furan concentrations in regular ground coffee brews from an espresso coffee machine were higher (43-146ng/ml) than those obtained from a home drip coffee maker (20 and 78ng/ml), while decaffeinated coffee brews from a home drip coffee maker (14-65ng/ml) showed a furan concentration similar to that obtained from regular coffee. Relatively low concentrations of this compound (12-35ng/ml) were found in instant coffee brews, while commercial packed coffee capsules showed the highest concentrations (117-244ng/ml). Finally, the daily intake of furan through coffee consumption in Barcelona (Spain) (0.03-0.38μg/kg of body weight) was estimated. Copyright © 2010 Elsevier Ltd. All rights reserved.

Replication-guided nucleosome packing and nucleosome breathing expedite the formation of dense arrays

PubMed Central

Osberg, Brendan; Nuebler, Johannes; Korber, Philipp; Gerland, Ulrich

2014-01-01

The first level of genome packaging in eukaryotic cells involves the formation of dense nucleosome arrays, with DNA coverage near 90% in yeasts. How cells achieve such high coverage within a short time, e.g. after DNA replication, remains poorly understood. It is known that random sequential adsorption of impenetrable particles on a line reaches high density extremely slowly, due to a jamming phenomenon. The nucleosome-shifting action of remodeling enzymes has been proposed as a mechanism to resolve such jams. Here, we suggest two biophysical mechanisms which assist rapid filling of DNA with nucleosomes, and we quantitatively characterize these mechanisms within mathematical models. First, we show that the ‘softness’ of nucleosomes, due to nucleosome breathing and stepwise nucleosome assembly, significantly alters the filling behavior, speeding up the process relative to ‘hard’ particles with fixed, mutually exclusive DNA footprints. Second, we explore model scenarios in which the progression of the replication fork could eliminate nucleosome jamming, either by rapid filling in its wake or via memory of the parental nucleosome positions. Taken together, our results suggest that biophysical effects promote rapid nucleosome filling, making the reassembly of densely packed nucleosomes after DNA replication a simpler task for cells than was previously thought. PMID:25428353

Polygonal crack patterns by drying thin films under quasi-two-dimensional confinement

NASA Astrophysics Data System (ADS)

Ma, Xiaolei; Lowensohn, Janna; Burton, Justin

Cracks patterns such as T/Y junction cracks in dried mud are ubiquitous in nature. Although the conditions for cracking in solids is well-known, cracks in colloidal and granular systems are more complex. Here we report the formations of polygonal cracks by drying thin films of corn starch ( 10 μm in diameter) under quasi-2D confinement. We find there are two drying stages before the films are completely dried. Initially, a compaction front invades throughout the film. Then, a second drying stage ''percolates'' throughout the film with a characteristic branching pattern, leading to a dense packing of particles connected by liquid capillary bridges. Finally, polygonal cracks appear as the remaining liquid dries. The same drying kinetics occur for films with different thickness, h, except that fractal-like fracture patterns form in thin films, where the thickness is comparable to the particle size, while polygons form in thick films with many layers of particles. We also find that the average area of the polygons, A, in fully dried films scales with the thickness, A hβ , where β 1 . 5 , and the prefactor depends on the initial packing fraction of the suspension. This form is consistent with a simple energy balance criterion for crack formation.

Role of dbnd NOH intermolecular interactions in oxime derivatives via Crystal structure, Hirshfeld surface, PIXELC and DFT calculations

NASA Astrophysics Data System (ADS)

Purushothaman, Gayathri; Thiruvenkatam, Vijay

2017-11-01

Oximes are building block of organic synthesis and they have wide range applications in laboratories, industries, and pharmaceutical as antidotes. Herein we report the crystal structures of oxime derivative Beta-p-Dimethylaminodeoxybenzionoxime (I) and o-Chloro-p-dimethylaminodeoxybenzion (II) the precursor molecule of o-Chloro-p-dimethylaminodeoxybenzionoxime and their intermolecular interactions studies through Hirshfeld surface & 2D-fingerprint plot analysis along with PIXELC and DFT calculations. The packing arrangements in I and II are driven by Osbnd H⋯N and Osbnd H⋯C interactions respectively. The Osbnd H⋯N hydrogen bonding in I facilitates the formation of the dimer with the motif of R (22(6)), whereas in II absence of oxime moiety (dbnd NOH) restricts the dimer formation. The 2D-fingerprint plot shows the close contacts for the intermolecular interactions in I & II. The PIXELC calculation of II suggests Osbnd H⋯C contributes for intermolecular interaction that stabilizes the crystal packing with the total energy value of 60.4 kcal/mol. The DFT calculation using B3LYP with 6-311G (d, p) functional set for both the derivatives shows a small deviation in the benzene ring (I) and chlorobenzene ring (II) with the RMSD value of 0.5095 Å and 0.8472 Å respectively.

Frozen chips: an unusual cause of severe frostbite injury

PubMed Central

Graham, C.; Stevenson, J.

2000-01-01

A case of severe frostbite injury to the right foot is presented. This was caused by the inappropriate application of a bag of frozen chips to the foot in an attempt to ease non-specific pain. No specific acute traumatic injury was identified. As the patient was a teacher of physical education, the pain had initially been assumed to originate from a minor musculoskeletal injury. Full recovery ensued after surgical excision of necrotic tissue and split skin grafting. The danger of inappropriate overenthusiastic use of ice packs or other frozen material to treat soft tissue injuries is emphasised. The need for education to prevent similar future injuries is discussed. Key Words: cold injury; frostbite; ice pack; skin; necrosis PMID:11049150

Entropy favours open colloidal lattices

NASA Astrophysics Data System (ADS)

Mao, Xiaoming; Chen, Qian; Granick, Steve

2013-03-01

Burgeoning experimental and simulation activity seeks to understand the existence of self-assembled colloidal structures that are not close-packed. Here we describe an analytical theory based on lattice dynamics and supported by experiments that reveals the fundamental role entropy can play in stabilizing open lattices. The entropy we consider is associated with the rotational and vibrational modes unique to colloids interacting through extended attractive patches. The theory makes predictions of the implied temperature, pressure and patch-size dependence of the phase diagram of open and close-packed structures. More generally, it provides guidance for the conditions at which targeted patchy colloidal assemblies in two and three dimensions are stable, thus overcoming the difficulty in exploring by experiment or simulation the full range of conceivable parameters.

Preparation of porous hollow silica spheres via a layer-by-layer process and the chromatographic performance

NASA Astrophysics Data System (ADS)

Wei, Xiaobing; Gong, Cairong; Chen, Xujuan; Fan, Guoliang; Xu, Xinhua

2017-03-01

Hollow silica spheres possessing excellent mechanical properties were successfully prepared through a layer-by-layer process using uniform polystyrene (PS) latex fabricated by dispersion polymerization as template. The formation of hollow SiO2 micro-spheres, structures and properties were observed in detail by zeta potential, SEM, TEM, FTIR, TGA and nitrogen sorption porosimetry. The results indicated that the hollow spheres were uniform with particle diameter of 1.6 μm and shell thickness of 150 nm. The surface area was 511 m2/g and the pore diameter was 8.36 nm. A new stationary phase for HPLC was obtained by using C18-derivatized hollow SiO2 micro-spheres as packing materials and the chromatographic properties were evaluated for the separation of some regular small molecules. The packed column showed low column pressure, high values of efficiency (up to about 43 000 plates/m) and appropriate asymmetry factors.

Navier-Stokes hydrodynamics of thermal collapse in a freely cooling granular gas.

PubMed

Kolvin, Itamar; Livne, Eli; Meerson, Baruch

2010-08-01

We show that, in dimension higher than one, heat diffusion and viscosity cannot arrest thermal collapse in a freely evolving dilute granular gas, even in the absence of gravity. Thermal collapse involves a finite-time blowup of the gas density. It was predicted earlier in ideal, Euler hydrodynamics of dilute granular gases in the absence of gravity, and in nonideal, Navier-Stokes granular hydrodynamics in the presence of gravity. We determine, analytically and numerically, the dynamic scaling laws that characterize the gas flow close to collapse. We also investigate bifurcations of a freely evolving dilute granular gas in circular and wedge-shaped containers. Our results imply that, in general, thermal collapse can only be arrested when the gas density becomes comparable with the close-packing density of grains. This provides a natural explanation to the formation of densely packed clusters of particles in a variety of initially dilute granular flows.

Crystal structure of 2-meth-oxy-2-[(4-meth-oxy-phen-yl)sulfan-yl]-1-phenyl-ethanone.

PubMed

Caracelli, Ignez; Olivato, Paulo R; Traesel, Henrique J; Valença, Jéssica; Rodrigues, Daniel N S; Tiekink, Edward R T

2015-09-01

In the title β-thio-carbonyl compound, C16H16O3S, the adjacent meth-oxy and carbonyl O atoms are synperiplanar [the O-C-C-O torsion angle is 19.8 (4)°] and are separated by 2.582 (3) Å. The dihedral angle between the rings is 40.11 (16)°, and the meth-oxy group is coplanar with the benzene ring to which it is connected [the C-C-O-C torsion angle is 179.1 (3)°]. The most notable feature of the crystal packing is the formation of methine and methyl C-H⋯O(carbon-yl) inter-actions that lead to a supra-molecular chain with a zigzag topology along the c axis. Chains pack with no specific inter-molecular inter-actions between them.

Topologically Close-packed Phase Formation in High Entropy Alloys: A Review of Calphad and Experimental Results

NASA Astrophysics Data System (ADS)

Guruvidyathri, K.; Hari Kumar, K. C.; Yeh, J. W.; Murty, B. S.

2017-11-01

One of the major challenges in high entropy alloy (HEA) research is to obtain single-phase solid solutions by proper selection of components and processing techniques. Often one encounters situations where topologically close-packed (TCP) phases are present in the HEA microstructures. TCP phases are a class of intermetallic phases that are in general considered undesirable. The ability to predict these phases in HEAs using the Calphad (CALculation of PHAse Diagrams) method has been shown to accelerate the identification of promising compositions. In this review, an analysis of the reported Calphad studies and corresponding microstructural information on HEAs is done to evaluate the success of the Calphad method for TCP phases. A total of 52 alloys with 123 post-heat treatment microstructures reported so far have been compared. Challenges and issues in experiments and calculations are brought out with a possible way forward.

Spontaneously Flowing Crystal of Self-Propelled Particles

NASA Astrophysics Data System (ADS)

Briand, Guillaume; Schindler, Michael; Dauchot, Olivier

2018-05-01

We experimentally and numerically study the structure and dynamics of a monodisperse packing of spontaneously aligning self-propelled hard disks. The packings are such that their equilibrium counterparts form perfectly ordered hexagonal structures. Experimentally, we first form a perfect crystal in a hexagonal arena which respects the same crystalline symmetry. Frustration of the hexagonal order, obtained by removing a few particles, leads to the formation of a rapidly diffusing "droplet." Removing more particles, the whole system spontaneously forms a macroscopic sheared flow, while conserving an overall crystalline structure. This flowing crystalline structure, which we call a "rheocrystal," is made possible by the condensation of shear along localized stacking faults. Numerical simulations very well reproduce the experimental observations and allow us to explore the parameter space. They demonstrate that the rheocrystal is induced neither by frustration nor by noise. They further show that larger systems flow faster while still remaining ordered.

Effects of synoptic patterns on atmospheric chemistry and aerosols during the Arctic Ocean Expedition 1996

NASA Astrophysics Data System (ADS)

Nilsson, E. Douglas; Barr, Sumner

2001-12-01

The atmospheric program on the Arctic Ocean Expedition of July through September 1996 (AOE-96) was focused on aerosol climate feedback. The expedition took place close to the saddle point between a semipersistent anticyclonic ridge from near Scandinavia to the Arctic coast of eastern Siberia and a trough from the Canadian archipelago across the pole to north central Siberia. The weather varied from anticyclonic clear-sky conditions to cyclonic cloudy conditions, and 13 identifiable migratory features (frontal bands, wave disturbances) clearly influenced local weather, clouds, atmospheric transport, and chemistry. This includes an explosive polar cyclone, born at the lateral heat gradient between Greenland and the pack ice rather than between open sea and the pack ice. The synoptic scale weather systems caused the strongest variability in trace gases (O3 in particular) and aerosols, and also strong variability in the cloud cover. The formation of air masses over the pack ice primarily depends on if there is cyclonic (convergent) or anticyclonic (divergent) flow. Cyclonic flow resulted in a modified marine air mass loaded with vapor, but with low aerosol number concentrations owing to frequent clouds and fogs and efficient cloud scavenging of the aerosol. Anticyclonic flow resulted in almost continental air masses with clear sky, long residence time over the pack ice and subsidence slowly replacing the boundary layer with free tropospheric air, low vapor concentrations, but large aerosol number in lack of efficient cloud scavenging. The synoptic variability and advection from south of the ice edge were weaker than during the predecessor International Arctic Ocean Expedition in 1991 (IAOE-91), when on average the sampled air spent 55 hours over the pack ice compared to more than 120 hours during AOE-96, owing to exceptionally high cyclone activity in 1991. This caused a large difference in atmospheric transport, chemistry, and aerosols between the two expeditions.

Drying in porous media with gravity-stabilized fronts: experimental results.

PubMed

Yiotis, A G; Salin, D; Tajer, E S; Yortsos, Y C

2012-08-01

In a recent paper [Yiotis et al., Phys. Rev. E 85, 046308 (2012)] we developed a model for the drying of porous media in the presence of gravity. It incorporated effects of corner film flow, internal and external mass transfer, and the effect of gravity. Analytical results were derived when gravity opposes drying and hence leads to a stable percolation drying front. In this paper, we test the theory using laboratory experiments. A series of isothermal drying experiments in glass bead packings saturated with volatile hydrocarbons is conducted. The transparent glass cells containing the packing allow for the visual monitoring of the phase distribution patterns below the surface, including the formation of liquid films, as the gaseous phase invades the pore space, and for the control of the thickness of the diffusive mass boundary layer over the packing. The experimental results agree very well with theory, provided that the latter is generalized to account for the effects of corner roundness in the film region (which was neglected in the theoretical part). We demonstrate the existence of an early constant rate period (CRP), which lasts as long as the films saturate the surface of the packing, and of a subsequent falling rate period (FRP), which begins practically after the detachment of the film tips from the external surface. During the CRP, the process is controlled by diffusion within the stagnant gaseous phase in the upper part of the cells, yielding a Stefan tube problem solution. During the FRP, the process is controlled by diffusion within the packing, with a drying rate inversely proportional to the observed position of the film tips in the cell. Theoretical and experimental results compare favorably for a specific value of the roundness of the films, which is found to be constant and equal to 0.2 for various conditions, and verify the theoretical dependence on the capillary Ca(f), Bond Bo, and Sherwood Sh numbers.

Silicon Whisker and Carbon Nanofiber Composite Anode

NASA Technical Reports Server (NTRS)

Lang, Christopher M.

2015-01-01

Phase II Objectives: Demonstrate production levels of grams per batch; Achieve full cell anode capacity of greater than 1,000 mAh/g at a charge rate of 10 (C/10) and 0 degree C; Establish a full cell cycle life of over 300 cycles; Display an operating temperature of negative 30 degrees C to plus 30 degrees C; Demonstrate a rate capability of C/5 or higher; Deliver to NASA three 2.5 Ah cells (energy density greater than 220 Wh/kg); Exhibit the safety features of the anode and full cells; Design a 1 kWh prismatic battery pack.

An ESEM investigation of latex film formation in cement pore solution

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gretz, M.; Plank, J., E-mail: sekretariat@bauchemie.ch.tum.d

2011-02-15

Environmental scanning electron microscopy (ESEM) and complementary methods were employed to study the time dependent film formation of a latex dispersion in water and cement pore solution. First, a model carboxylated styrene/n-butyl acrylate latex dispersion possessing a minimum film forming temperature (MFFT) of 18 {sup o}C was synthesized in aqueous media via emulsion polymerization. Its film forming property was at a temperature of 40 {sup o}C, studied under an ESEM. The analysis revealed that upon removal of water, film formation occurs as a result of particle packing, particle deformation and finally particle coalescence. Film formation is significantly retarded when themore » latex dispersion is present in cement pore solution. This effect can be ascribed to adsorption of Ca{sup 2+} ions onto the surface of the anionic latex particles and to interfacial secondary phases. This layer of adsorbed Ca{sup 2+} ions hinders interdiffusion of the macromolecules and subsequent film formation of the latex polymer.« less

Phenols removal using ozonation-adsorption with granular activated carbon (GAC) in rotating packed bed reactor

NASA Astrophysics Data System (ADS)

Karamah, E. F.; Leonita, S.; Bismo, S.

2018-01-01

Synthetic wastewater containing phenols was treated using combination method of ozonation-adsorption with GAC (Granular Activated Carbon) in a packed bed rotating reactor. Ozone reacts quickly with phenol and activated carbon increases the oxidation process by producing hydroxyl radicals. Performance parameters evaluated are phenol removal percentage, the quantity of hydroxyl radical formed, changes in pH and ozone utilization, dissolved ozone concentration and ozone concentration in off gas. The performance of the combination method was compared with single ozonation and single adsorption. The influence of GAC dose and initial pH of phenols were evaluated in ozonation-adsorption method. The results show that ozonation-adsorption method generates more OH radicals than a single ozonation. Quantity of OH radical formation increases with increasing pH and quantity of the GAC. The combination method prove better performance in removing phenols. At the same operation condition, ozonation-adsorption method is capable of removing of 78.62% phenols as compared with single ozonation (53.15%) and single adsorption (36.67%). The increasing percentage of phenol removal in ozonation-adsorption method is proportional to the addition of GAC dose, solution pH, and packed bed rotator speed. Maximum percentage of phenol removal is obtained under alkaline conditions (pH 10) and 125 g of GAC

Evaporation of NaCl solution from porous media with mixed wettability

NASA Astrophysics Data System (ADS)

Bergstad, Mina; Shokri, Nima

2016-05-01

Evaporation of saline water from porous media is ubiquitous in many processes including soil salinization, crop production, and CO2 sequestration in deep saline acquirer. It is controlled by the transport properties of porous media, atmospheric conditions, and properties of the evaporating saline solution. In the present study, the effects of mixed wettability conditions on the general dynamics of water evaporation from porous media saturated with NaCl solution were investigated. To do so, we conducted a comprehensive series of evaporation experiments using sand mixtures containing different fractions of hydrophobic grains saturated with NaCl solutions. Our results showed that increasing fraction of hydrophobic grains in the mixed wettability sand pack had minor impact on the evaporative mass losses due to the presence of salt whose precipitation patterns were significantly influenced by the mixed wettability condition. Through macroscale and microscale investigations, we found formation of patchy efflorescence in the case of mixed wettability sand pack as opposed to crusty efflorescence in the case of completely hydrophilic porous media. Furthermore, the presence of salty water and hydrophobic grains in the sand pack significantly influenced the general dynamics and morphology of the receding drying front. Our results extend the understanding of the saline water evaporation from porous media with direct applications to various hydrological and engineering processes.

Perception of front-of-pack labels according to social characteristics, nutritional knowledge and food purchasing habits.

PubMed

Méjean, Caroline; Macouillard, Pauline; Péneau, Sandrine; Hercberg, Serge; Castetbon, Katia

2013-03-01

To identify patterns of perception of front-of-pack (FOP) nutrition labels and to determine social factors, nutritional knowledge and attention to packaging features related to such patterns. Cross-sectional. Perception was measured using indicators of understanding and acceptability of three simple FOP labels (the 'Green Tick', the logo of the French Nutrition and Health Programme (PNNS logo) and 'simple traffic lights' (STL)) and two detailed formats ('multiple traffic lights' (MTL) and the 'colour range' logo (CR)). Associations of perception patterns with individual characteristics were examined using χ2 tests. Data from the French NutriNet-Santé cohort study. A total of 38,763 adults. Four perception patterns emerged. Poorly educated individuals were most often found in groups favouring simple formats. The 'favourable to CR' group had a high rate of men and older persons. Poor nutritional knowledge was more frequent in the 'favourable to STL' group, while individuals with substantial knowledge were proportionally more numerous in the 'favourable to MTL' group. The 'favourable to STL' group more frequently self-reported noting price and marketing characteristics during purchasing, while the 'favourable to MTL' and 'favourable to CR' groups declared more interest in nutritional information. The 'favourable to Green Tick and PNNS logo' group self-reported paying closer attention to claims and quality guarantee labels. The 'favourable to MTL' cluster was most frequently represented in our survey. However, simple FOP formats may be most appropriate for increasing awareness of healthy eating among targeted groups with poor nutritional knowledge and little interest in the nutritional quality of packaged foods.

Effect of aluminizing of Cr-containing ferritic alloys on the seal strength of a novel high-temperature solid oxide fuel cell sealing glass

NASA Astrophysics Data System (ADS)

Chou, Yeong-Shyung; Stevenson, Jeffry W.; Singh, Prabhakar

A novel high-temperature alkaline earth silicate sealing glass was developed for solid oxide fuel cell (SOFC) applications. The glass was used to join two metallic coupons of Cr-containing ferritic stainless steel for seal strength evaluation. In previous work, SrCrO 4 was found to form along the glass/steel interface, which led to severe strength degradation. In the present study, aluminization of the steel surface was investigated as a remedy to minimize or prevent the strontium chromate formation. Three different processes for aluminization were evaluated with Crofer22APU stainless steel: pack cementation, vapor-phase deposition, and aerosol spraying. It was found that pack cementation resulted in a rough surface with occasional cracks in the Al-diffused region. Vapor-phase deposition yielded a smoother surface, but the resulting high Al content increased the coefficient of thermal expansion (CTE), resulting in the failure of joined coupons. Aerosol spraying of an Al-containing salt resulted in the formation of a thin aluminum oxide layer without any surface damage. The room temperature seal strength was evaluated in the as-fired state and in environmentally aged conditions. In contrast to earlier results with uncoated Crofer22APU, the aluminized samples showed no strength degradation even for samples aged in air. Interfacial and chemical compatibility was also investigated. The results showed aluminization to be a viable candidate approach to minimize undesirable chromate formation between alkaline earth silicate sealing glass and Cr-containing interconnect alloys for SOFC applications.

4-Mercaptophenylboronic acid SAMs on gold: comparison with SAMs derived from thiophenol, 4-mercaptophenol, and 4-mercaptobenzoic acid.

PubMed

Barriet, David; Yam, Chi Ming; Shmakova, Olga E; Jamison, Andrew C; Lee, T Randall

2007-08-14

We report the formation and characterization of self-assembled monolayers (SAMs) derived from the adsorption of 4-mercaptophenylboronic acid (MPBA) on gold. For comparison, SAMs derived from the adsorption of thiophenol (TP), 4-mercaptophenol (MP), and 4-mercaptobenzoic acid (MBA) were also examined. The structure and properties of the SAMs were evaluated by ellipsometry, contact-angle goniometry, polarization-modulation infrared reflection-absorption spectroscopy (PM-IRRAS), and X-ray photoelectron spectroscopy (XPS). Specifically, ellipsometry was used to assess the formation of monolayer films, and contact angle measurements were used to determine the surface hydrophilicity and homogeneity. Separately, PM-IRRAS was used to evaluate the molecular composition and orientation as well as the intermolecular hydrogen bonding within the SAMs. Finally, XPS was used to evaluate the film composition and surface coverage (i.e., packing density), which was observed to increase in the following order: TP < MP < MPBA < MBA. A rationalization for the observed packing differences is presented. The XPS data indicate further that ultrahigh vacuum conditions induce the partial dehydration of MPBA SAMs with the concomitant formation of surface boronic anhydride species. Overall, the analytical data collectively show that the MPBA moieties in the SAMs exist in the acid form rather than the anhydride form under ambient laboratory conditions. Furthermore, stability studies find that MPBA SAMs are surprisingly labile in basic solution, where the terminal B-C bonds are cleaved by the attack of hydroxide ion and strongly basic amine nucleophiles. The unanticipated lability observed here should be considered by those wishing to use MPBA moieties in carbohydrate-sensing applications.

Studies of mixed-chain diacyl phosphatidylcholines with highly asymmetric acyl chains: a Fourier transform infrared spectroscopic study of interfacial hydration and hydrocarbon chain packing in the mixed interdigitated gel phase.

PubMed Central

Lewis, R N; McElhaney, R N

1993-01-01

The mixed interdigitated gel phases of unlabeled, specifically 13C = O-labeled, and specifically chain-perdeuterated samples of 1-O-eicosanoyl, 2-O-lauroyl phosphatidylcholine and 1-O-decanoyl, 2-O-docosanoyl phosphatidylcholine were studied by infrared spectroscopy. Our results suggest that at the liquid-crystalline/gel phase transition temperatures of these lipids, there is a greater redistribution in the populations of free and hydrogen-bonded ester carbonyl groups than is commonly observed with symmetric chain n-saturated diacyl phosphatidylcholines. The formation of the mixed interdigitated gel phase coincides with the appearance of a marked asymmetry in the contours of the C = O stretching band, a process which becomes more pronounced as the temperature is reduced. This asymmetry is ascribed to the emergence of a predominant lipid population consisting of free sn1- and hydrogen-bonded (hydrated) sn2-ester carbonyl groups. This suggests that the region of the mixed interdigitated bilayer polar/apolar interface near to the sn1-ester carbonyl group is less hydrated than is the case with the noninterdigitated gel-phase bilayers formed by normal symmetric chain phosphatidylcholines. In the methylene deformation region of the spectrum, the unlabeled lipids exhibit a pronounced splitting of the CH2 scissoring bands. This splitting is significantly attenuated when the short chains are perdeuterated and collapses completely upon perdeuteration of the long chains, irrespective of whether the long (or short) chains are esterified to the sn1 or sn2 positions of the glycerol backbone. These results are consistent with a global hydrocarbon chain packing motif in which the zigzag planes of the hydrocarbon chains are perpendicular to each other and the sites occupied by long chains are twice as numerous as those occupied by short chains. The experimental support for this chain-packing motif enabled more detailed considerations of the possible ways in which these lipid molecules are assembled in the mixed interdigitated gel phase. Generally, our results are compatible with a previously proposed model in which the mixed interdigitated gel phase is an assembly of repeat units which consists of two phosphatidylcholine molecules forming a triple-chain structure with the long chains traversing the bilayer and with the methyl termini of the shorter chains opposed at the bilayer center. Our data also suggest that the packing format which is most consistent with our results and previously published work is one in which the hydrocarbon chains of each repeat unit are parallel to each other with the repeat units themselves being perpendicularly packed. PMID:8298016

Microstructure and phase behavior in colloids and liquid crystals

NASA Astrophysics Data System (ADS)

Lohr, Matthew Alan

This thesis describes our investigation of microstructure and phase behavior in colloids and liquid crystals. The first set of experiments explores the phase behavior of helical packings of thermoresponsive microspheres inside glass capillaries as a function of volume fraction. Stable helical packings are observed with long-range orientational order. Some of these packings evolve abruptly to disordered states as the volume fraction is reduced. We quantify these transitions using correlation functions and susceptibilities of an orientational order parameter. The emergence of coexisting metastable packings, as well as coexisting ordered and disordered states, is also observed. These findings support the notion of phase-transition-like behavior in quasi-one-dimensional systems. The second set of experiments investigates cross-over behavior from glasses with attractive interactions to sparse gel-like states. In particular, the vibrational modes of quasi-two-dimensional disordered colloidal packings of hard colloidal spheres with short-range attractions are measured as a function of packing fraction. A crossover from glassy to sparse gel-like states is indicated by an excess of low-frequency phonon modes. This change in vibrational mode distribution appears to arise from highly localized vibrations that tend to involve individual and/or small clusters of particles with few local bonds. These mode behaviors and corresponding structural insights may serve as a useful signature for glass-gel transitions in wider classes of attractive packings. A third set of experiments explores the director structures of aqueous lyotropic chromonic liquid crystal (LCLC) films created on square lattice cylindrical-micropost substrates. The structures are manipulated by modulating of the concentration-dependent elastic properties of LCLC s via drying. Nematic LCLC films exhibit preferred bistable alignment along the diagonals of the micropost lattice. Columnar LCLC films form two distinct director and defect configurations: a diagonally aligned director pattern with local squares of defects, and an off-diagonal configuration with zig-zag defects. The formation of these patterns appears to be tied to the relative free energy costs of splay and bend deformations in the precursor nematic films. The observed nematic and columnar configurations are understood numerically using a Landau-de Gennes free energy model. This work provides first examples of quasi-2D micropatterning of LC films in the columnar phase and the first micropatterning of lyotropic LC films in general, as well as demonstrating alignment and configuration switching of typically difficult-to-align LCLC films via bulk elastic properties.

Factors determining the average atomic volumes in intermetallic compounds

PubMed Central

Pauling, Linus

1987-01-01

In formation of an intermetallic compound from the elementary metals there is usually a contraction in volume. Electron transfer leading to the charge states M+ and M- with increase in valence and decrease in volume explains the more than 2-fold range in contraction for different compounds in the same binary system. In a more thorough analysis, the better packing of atoms of different sizes also needs to be considered. PMID:16578809

Roughening of Pt nanoparticles induced by surface-oxide formation.

PubMed

Zhu, Tianwei; Hensen, Emiel J M; van Santen, Rutger A; Tian, Na; Sun, Shi-Gang; Kaghazchi, Payam; Jacob, Timo

2013-02-21

Using density functional theory (DFT) and thermodynamic considerations we studied the equilibrium shape of Pt nanoparticles (NPs) under electrochemical conditions. We found that at very high oxygen coverage, obtained at high electrode potentials, the experimentally-observed tetrahexahedral (THH) NPs consist of high-index (520) faces. Since high-index surfaces often show higher (electro-)chemical activity in comparison to their close-packed counterparts, the THH NPs can be promising candidates for various (electro-)catalytic applications.

Hierarchical Structure in Polymeric Solids and Its Influence on Properties

DTIC Science & Technology

1989-05-01

consequences for the systematic design of phase behaviour. Also it is one of the several illustrations that the ’rigid’ group in itself need not...identified the factors controlling mesogen (or in general, rigid group ) packing in segmented LCP forming polymers and its influence on layer formation at...molecules in solution and controlled preparation of model systems" in Rigid Rod Polymers, Materials Research Publication, Ed. W. Adams, in the press

Structure Formation in Solutions of Rigid Polymers Undergoing a Phase Transition

DTIC Science & Technology

1987-04-01

cyclohexene dioxide (ERL-4206) - 10 g. nonenyl succinic anhydride (NSA) - 26 g. dimethyl amino ethanol ( DMAE ) - 0.4 g. After infiltration, short segments...existence of a significant number of defects within the individual microfibril. The presence of defects in the lateral packing of PBT chains is also suggested...of the D- and L- enantiomers yields a nematic phase. The ordered phases exhi- bit complex textures due to defects (disclinations) which depend on

Impact of female-oriented cigarette packaging in the United States.

PubMed

Hammond, David; Doxey, Juliana; Daniel, Samantha; Bansal-Travers, Maansi

2011-07-01

Cigarette packaging is among the most prominent forms of tobacco marketing. This study examined the impact of cigarette pack design among young women in the United States. A national sample of 18- to 19-year-old females in the United States completed an online survey in February 2010. Participants were randomized to view eight cigarette packs designed according to one of four experimental conditions: fully branded female packs, same packs without descriptors (e.g., "slims"), same packs without brand imagery or descriptors ("plain" packs), and branded non-female brands. Participants rated packs on measures of appeal and health risk and completed a behavioral pack selection task. Fully branded female packs were rated significantly more appealing than the same packs without descriptors, "plain" packs, and non-female-branded packs. Female-branded packs were associated with a greater number of positive attributes including glamour, slimness, and attractiveness and were more likely to be perceived as less harmful. Approximately 40% of smokers and nonsmokers requested a pack at the end of the study; female-branded packs were 3 times more likely to be selected than plain packs. Plain packaging and removing descriptors such as "slims" from cigarette packs may reduce smoking susceptibility among young women.

Programming While Construction of Engineering 3D Models of Complex Geometry

NASA Astrophysics Data System (ADS)

Kheyfets, A. L.

2017-11-01

The capabilities of geometrically accurate computational 3D models construction with the use of programming are presented. The construction of models of an architectural arch and a glo-boid worm gear is considered as an example. The models are designed in the AutoCAD pack-age. Three programs of construction are given. The first program is for designing a multi-section architectural arch. The control of the arch’s geometry by impacting its main parameters is shown. The second program is for designing and studying the working surface of a globoid gear’s worm. The article shows how to make the animation for this surface’s formation. The third program is for formation of a worm gear cavity surface. The cavity formation dynamics is studied. The programs are written in the AutoLisp programming language. The program texts are provided.

Chiral domain formation from the mixture of achiral rod-like liquid crystal and tri boomerang-shaped molecule

NASA Astrophysics Data System (ADS)

Lee, Ji-Hoon; Yoon, Tae-Hoon

2013-08-01

Spontaneous formation of chiral domains such as a helical filament and a bent-broom texture was observed from the mixture of a rod-like liquid crystal octylcyano-biphenyl (8CB) and a tri boomerang-shaped 2,4,6-triphenoxy-1,3,5-triazine (triphenoxy) molecule. Although the constituent molecules were achiral, their mixture showed the chiral domains with the equal fraction of the opposite handedness. No tilt of 8CB molecules in the smectic layer was observed, implying the chirality is not due to the polar packing and tilt of the molecules. In addition, the splay and bend elastic constant of 8CB was decreased after doping triphenoxy. A structural conformation of triphenoxy and an orientational coupling between 8CB and triphenoxy are considered to be related to the chiral domain formation.

Critiques of the seismic hypothesis and the vegetation stabilization hypothesis for the formation of Mima mounds along the western coast of the U.S.

NASA Astrophysics Data System (ADS)

Gabet, Emmanuel J.; Burnham, Jennifer L. Horwath; Perron, J. Taylor

2016-09-01

A recent paper published in Geomorphology by Gabet et al. (2014) presents the results of a numerical model supporting the hypothesis that burrowing mammals build Mima mounds - small, densely packed hillocks found primarily in the western United States. The model is based on field observations and produces realistic-looking mounds with spatial distributions similar to real moundfields. Alternative explanations have been proposed for these Mima mounds, including formation by seismic shaking and vegetation-controlled erosion and deposition. In this short communication, we present observations from moundfields in the coastal states of the western U.S. that are incompatible with these alternative theories.

Symmetric scrolled packings of multilayered carbon nanoribbons

NASA Astrophysics Data System (ADS)

Savin, A. V.; Korznikova, E. A.; Lobzenko, I. P.; Baimova, Yu. A.; Dmitriev, S. V.

2016-06-01

Scrolled packings of single-layer and multilayer graphene can be used for the creation of supercapacitors, nanopumps, nanofilters, and other nanodevices. The full atomistic simulation of graphene scrolls is restricted to consideration of relatively small systems in small time intervals. To overcome this difficulty, a two-dimensional chain model making possible an efficient calculation of static and dynamic characteristics of nanoribbon scrolls with allowance for the longitudinal and bending stiffness of nanoribbons is proposed. The model is extended to the case of scrolls of multilayer graphene. Possible equilibrium states of symmetric scrolls of multilayer carbon nanotribbons rolled up so that all nanoribbons in the scroll are equivalent are found. Dependences of the number of coils, the inner and outer radii, lowest vibrational eigenfrequencies of rolled packages on the length L of nanoribbons are obtained. It is shown that the lowest vibrational eigenfrequency of a symmetric scroll decreases with a nanoribbon length proportionally to L -1. It is energetically unfavorable for too short nanoribbons to roll up, and their ground state is a stack of plane nanoribbons. With an increasing number k of layers, the nanoribbon length L necessary for creation of symmetric scrolls increases. For a sufficiently small number of layers k and a sufficiently large nanoribbon length L, the scrolled packing has the lowest energy as compared to that of stack of plane nanoribbons and folded structures. The results can be used for development of nanomaterials and nanodevices on the basis of graphene scrolled packings.

Impact of Female-Oriented Cigarette Packaging in the United States

PubMed Central

Doxey, Juliana; Daniel, Samantha; Bansal-Travers, Maansi

2011-01-01

Introduction: Cigarette packaging is among the most prominent forms of tobacco marketing. This study examined the impact of cigarette pack design among young women in the United States. Method: A national sample of 18- to 19-year-old females in the United States completed an online survey in February 2010. Participants were randomized to view eight cigarette packs designed according to one of four experimental conditions: fully branded female packs, same packs without descriptors (e.g., “slims”), same packs without brand imagery or descriptors (“plain” packs), and branded non-female brands. Participants rated packs on measures of appeal and health risk and completed a behavioral pack selection task. Results: Fully branded female packs were rated significantly more appealing than the same packs without descriptors, “plain” packs, and non–female-branded packs. Female-branded packs were associated with a greater number of positive attributes including glamour, slimness, and attractiveness and were more likely to be perceived as less harmful. Approximately 40% of smokers and nonsmokers requested a pack at the end of the study; female-branded packs were 3 times more likely to be selected than plain packs. Conclusion: Plain packaging and removing descriptors such as “slims” from cigarette packs may reduce smoking susceptibility among young women. PMID:21486994

Manufacture of a four-sheet complex component from different titanium alloys by superplastic forming

NASA Astrophysics Data System (ADS)

Allazadeh, M. R.; Zuelli, N.

2017-10-01

A superplastic forming (SPF) technology process was deployed to form a complex component with eight-pocket from a four-sheet sandwich panel sheetstock. Six sheetstock packs were composed of two core sheets made of Ti-6Al-4V or Ti-5Al-4Cr-4Mo-2Sn-2Zr titanium alloy and two skin sheets made of Ti-6Al-4V or Ti-6Al-2Sn-4Zr-2Mo titanium alloy in three different combinations. The sheets were welded with two subsequent welding patterns over the core and skin sheets to meet the required component's details. The applied welding methods were intermittent and continuous resistance seam welding for bonding the core sheets to each other and the skin sheets over the core panel, respectively. The final component configuration was predicted based on the die drawings and finite element method (FEM) simulations for the sandwich panels. An SPF system set-up with two inlet gas pipe feeding facilitated the trials to deliver two pressure-time load cycles acting simultaneously which were extracted from FEM analysis for specific forming temperature and strain rate. The SPF pressure-time cycles were optimized via GOM scanning and visually inspecting some sections of the packs in order to assess the levels of core panel formation during the inflation process of the sheetstock. Two sets of GOM scan results were compared via GOM software to inspect the surface and internal features of the inflated multisheet packs. The results highlighted the capability of the tested SPF process to form complex components from a flat multisheet pack made of different titanium alloys.

Nanoscale Packing Differences in Sphingomyelin and Phosphatidylcholine Revealed by BODIPY Fluorescence in Monolayers: Physiological Implications

PubMed Central

2015-01-01

Phosphatidycholines (PC) with two saturated acyl chains (e.g., dipalmitoyl) mimic natural sphingomyelin (SM) by promoting raft formation in model membranes. However, sphingoid-based lipids, such as SM, rather than saturated-chain PCs have been implicated as key components of lipid rafts in biomembranes. These observations raise questions about the physical packing properties of the phase states that can be formed by these two major plasma membrane lipids with identical phosphocholine headgroups. To investigate, we developed a monolayer platform capable of monitoring changes in surface fluorescence by acquiring multiple spectra during measurement of a lipid force–area isotherm. We relied on the concentration-dependent emission changes of 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY)-labeled PC to detect nanoscale alterations in lipid packing and phase state induced by monolayer lateral compression. The BODIPY-PC probe contained an indacene ring with four symmetrically located methyl (Me) substituents to enhance localization to the lipid hydrocarbon region. Surface fluorescence spectra indicated changes in miscibility even when force–area isotherms showed no deviation from ideal mixing behavior in the surface pressure versus cross-sectional molecular area response. We detected slightly better mixing of Me4-BODIPY-8-PC with the fluid-like, liquid expanded phase of 1-palmitoyl-2-oleoyl-PC compared to N-oleoyl-SM. Remarkably, in the gel-like, liquid condensed phase, Me4-BODIPY-8-PC mixed better with N-palmitoyl-SM than dipalmitoyl-PC, suggesting naturally abundant SMs with saturated acyl chains form gel-like lipid phase(s) with enhanced ability to accommodate deeply embedded components compared to dipalmitoyl-PC gel phase. The findings reveal a fundamental difference in the lateral packing properties of SM and PC that occurs even when their acyl chains match. PMID:24564829

Wind tunnel experiments: influence of erosion and deposition on wind-packing of new snow

NASA Astrophysics Data System (ADS)

Sommer, Christian G.; Lehning, Michael; Fierz, Charles

2018-01-01

Wind sometimes creates a hard, wind-packed layer at the surface of a snowpack. The formation of such wind crusts was observed during wind tunnel experiments with combined SnowMicroPen and Microsoft Kinect sensors. The former provides the hardness of new and wind-packed snow and the latter spatial snow depth data in the test section. Previous experiments showed that saltation is necessary but not sufficient for wind-packing. The combination of hardness and snow depth data now allows to study the case with saltation in more detail. The Kinect data requires complex processing but with the appropriate corrections, snow depth changes can be measured with an accuracy of about 1 mm. The Kinect is therefore well suited to quantify erosion and deposition. We found that no hardening occurred during erosion and that a wind crust may or may not form when snow is deposited. Deposition is more efficient at hardening snow in wind-exposed than in wind-sheltered areas. The snow hardness increased more on the windward side of artificial obstacles placed in the wind tunnel. Similarly, the snow was harder in positions with a low Sx parameter. Sx describes how wind-sheltered (high Sx) or wind-exposed (low Sx) a position is and was calculated based on the Kinect data. The correlation between Sx and snow hardness was -0.63. We also found a negative correlation of -0.4 between the snow hardness and the deposition rate. Slowly deposited snow is harder than a rapidly growing accumulation. Sx and the deposition rate together explain about half of the observed variability of snow hardness.

[Properties and infiltration arts of machinable infiltration ceramic(MIC)].

PubMed

Yang, H; Xian, S; Liao, Y; Xue, Y; Chai, F

2000-06-01

The purpose of this study is to explore the infiltration arts of MIC and study the effects of different packing density of Al2O3 matrix on the properties of MIC. alpha-Al2O3 specimens were fabricated by pouring alpha-Al2O3 slip with different powder/liquid ratios(P/L = 3.5, 7.5, 10.5) into a mold, and subsequently pre-fired at 1160 degrees C for 6 hours to form Al2O3 matrix. The packing density of the matrices were measured. Infiltration concepts were introduced into this study by infiltrating molten mica micro-crystalline glass into the porous Al2O3 matrix at 1160 degrees C for 6 hours to form a continuous interpenetrating composite. The composite then underwent micro-crystallization by nucleating at 550 degrees C for 1 hour and crystallizing at 900 degrees C for 1 hour, which resulted in the MIC. Mechanical properties including three point flexural strength, elastic modulus, Vicker's hardness, indentation fracture toughness and Weibull's modulus of flexural strength were determined. Parameters of machinability(H/KIC)2 of MIC were calculated. XRD and SEM were employed to study its microstructure. The resulted matrices reached packing densities of 63%, 76%, 78% with P/L of 3.5, 7.5 and 10.5. The MIC attained high strength and good machinability after infiltration. Three-point flexural strength and indentation fracture toughness were 342, 431, 374 MPa and 4.05, 4.14, 5.02 MPa m1/2 for MIC with packing density of 63%, 76%, 78% separately. And parameters of machinability were 5.41, 6.84 and 7.39 respectively. Packing density of Al2O3 matrix significantly influenced the mechanical properties. Maximum properties were obtained with a matrix packing density of 75%(P/L = 7.5), with a Weibull's modulus of flexural strength of 6.8. Machinability decreased with the increase of P/L ratio. Micro-crystallizing treatment resulted in the formation of evenly distributed mica crystalline in the composite, which contributed to the high strength of this composite material. MIC is a new infiltrated ceramic with favorable strength and machinability which can satisfy the prosthodontic requirements as all ceramic crown and bridge materials, it also shows promising outlook for future developments and clinical usage.

Early Events in the Amyloid Formation of the A546T Mutant of Transforming Growth Factor β-Induced Protein in Corneal Dystrophies Compared to the Nonfibrillating R555W and R555Q Mutants.

PubMed

Koldsø, Heidi; Andersen, Ole Juul; Nikolajsen, Camilla Lund; Scavenius, Carsten; Sørensen, Charlotte S; Underhaug, Jarl; Runager, Kasper; Nielsen, Niels Chr; Enghild, Jan J; Schiøtt, Birgit

2015-09-15

The human transforming growth factor β-induced protein (TGFBIp) is involved in several types of corneal dystrophies where protein aggregation and amyloid fibril formation severely impair vision. Most disease-causing mutations are located in the last of four homologous fasciclin-1 (FAS1) domains of the protein, and it has been shown that when isolated, the fourth FAS1 domain (FAS1-4) mimics the behavior of full-length TGFBIp. In this study, we use molecular dynamics simulations and principal component analysis to study the wild-type FAS1-4 domain along with three disease-causing mutations (R555W, R555Q, and A546T) to decipher any internal difference in dynamical properties of the domains that may explain their varied stabilities and aggregation properties. In addition, we use a protein-protein docking method in combination with chemical cross-linking experiments and mass spectrometry of the cross-linked species to obtain information about interaction faces between identical FAS1-4 domains. The results show that the pathogenic mutations A546T and R555W affect the packing in the hydrophobic core of FAS1-4 in different directions. We further show that the FAS1-4 monomers associate using their β-rich regions, consistent with peptides observed to be part of the amyloid fibril core in lattice corneal dystrophy patients.

For a Growing Number of Freshmen, Packing for College Requires a Passport

ERIC Educational Resources Information Center

Wilhelm, Ian

2012-01-01

Dozens of universities have started encouraging students to go abroad early in their college life in the last decade, offering overseas opportunities that last a week to a full academic year, in countries as diverse as Britain, China, and Mexico. A variety of factors are driving the growth. Universities say the programs help globalize the…

Packed-bed catalytic cracking of oak derived pyrolytic vapors

USDA-ARS?s Scientific Manuscript database

Catalytic upgrading of pyrolysis vapors derived from oak was carried out using a fixed-bed catalytic column at 425 deg C. The vapors were drawn by splitting a fraction from the full stream of vapors produced at 500 deg C in a 5 kg/hr bench-scale fast pyrolysis reactor system downstream the cyclone s...

System and Method for High-Speed Data Recording

NASA Technical Reports Server (NTRS)

Taveniku, Mikael B. (Inventor)

2017-01-01

A system and method for high speed data recording includes a control computer and a disk pack unit. The disk pack is provided within a shell that provides handling and protection for the disk packs. The disk pack unit provides cooling of the disks and connection for power and disk signaling. A standard connection is provided between the control computer and the disk pack unit. The disk pack units are self sufficient and able to connect to any computer. Multiple disk packs are connected simultaneously to the system, so that one disk pack can be active while one or more disk packs are inactive. To control for power surges, the power to each disk pack is controlled programmatically for the group of disks in a disk pack.

Templated electrokinetic directed chemical assembly for the fabrication of close-packed plasmonic metamolecules

NASA Astrophysics Data System (ADS)

Thrift, W. J.; Darvishzadeh-Varcheie, M.; Capolino, F.; Ragan, R.

2017-08-01

Colloidal self-assembly combined with templated surfaces holds the promise of fabricating large area devices in a low cost facile manner. This directed assembly approach improves the complexity of assemblies that can be achieved with self-assembly while maintaining advantages of molecular scale control. In this work, electrokinetic driving forces, i.e., electrohydrodynamic flow, are paired with chemical crosslinking between colloidal particles to form close-packed plasmonic metamolecules. This method addresses challenges of obtaining uniformity in nanostructure geometry and nanometer scale gap spacings in structures. Electrohydrodynamic flows yield robust driving forces between the template and nanoparticles as well as between nanoparticles on the surface promoting the assembly of close-packed metamolecules. Here, electron beam lithography defined Au pillars are used as seed structures that generate electrohydrodynamic flows. Chemical crosslinking between Au surfaces enables molecular control over gap spacings between nanoparticles and Au pillars. An as-fabricated structure is analyzed via full wave electromagnetic simulations and shown to produce large magnetic field enhancements on the order of 3.5 at optical frequencies. This novel method for directed self-assembly demonstrates the synergy between colloidal driving forces and chemical crosslinking for the fabrication of plasmonic metamolecules with unique electromagnetic properties.

Suborbital missions: The Joust

NASA Technical Reports Server (NTRS)

Ferguson, Bruce W.

1991-01-01

Joust 1 will carry a payload of 10 experiments. The experiments in the payload module will be mated with a service module containing accelerometers, avionics, a low gravity rate control system, and battery packs. This suborbital mission will last approximately 21 minutes, providing at least 13 minutes of microgravity time. The experiments are as follow: study into polymer membrane processes; polymer curing; plasma particle generation; automated generic bioprocessing apparatus; biomodule; thin films; materials dispersion apparatus; foam formation; electrodeposition process; and powdered materials processing.

Singlet Fission and Excimer Formation in Disordered Solids of Alkyl-Substituted 1,3-Diphenylisobenzofurans

DOE PAGES

Dron, Paul I.; Michl, Josef; Johnson, Justin C.

2017-10-16

Here, we describe the preparation and excited state dynamics of three alkyl derivatives of 1,3-diphenylisobenzofuran (1) in both solutions and thin films. The substitutions are intended to disrupt the slip-stacked packing observed in crystals of 1 while maintaining the favorable energies of singlet and triplet for singlet fission (SF). All substitutions result in films that are largely amorphous as judged by the absence of strong X-ray diffraction peaks.

[Locus-controlling regions: description in the LCR-TRRD data base].

PubMed

Podkolodnaia, O A; Levitskiĭ, V G; Podkolodnyĭ, N L

2001-01-01

The structural and functional organization of locus control regions (LCR) was analyzed using data of the LCR-TRR Database. The role of several transcription factors in the LCR function was considered. A study was made of the possible nucleosomal packing of enhancer regions in LCR. The structure and the format of LCR-TRRD are described. The database has been constructed for SRS and is available at http://wwwmgs.bionet.nsc.ru/mgs/dbase/LCR/.

Formation of 4H-closely packed structure in thin films of metastable nanocrystalline Co 13Cu 87 alloy

NASA Astrophysics Data System (ADS)

Khalyapin, D. L.; Kim, J.; Stolyar, S. V.; Turpanov, I. A.; Kim, P. D.; Kim, I.

2003-11-01

The crystal structure of the thin films of metastable Co 13Cu 87 alloy prepared by magnetron sputtering was investigated by transmission electron microscope. As-deposited films have a nanocrystal structure with an fcc lattice. As a result of the prolonged ion polishing with a beam of Ar ions with the energy of 4.7 keV, the four-layer 4H dhcp structure was formed.

A comparative study of Sm networks in Al-10 at.%Sm glass and associated crystalline phases

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lv, Xiaobao; Ye, Zhuo; Sun, Yang

Here, the Al–Sm system is selected as a model system to study the transition process from liquid and amorphous to crystalline states. In recent work, we have shown that, in addition to long-range translational periodicity, crystal structures display well-defined short-range local atomic packing motifs that transcends liquid, amorphous and crystalline states. In this paper, we investigate the longer range spatial packing of these short-range motifs by studying the interconnections of Sm–Sm networks in different amorphous and crystalline samples obtained from molecular dynamics simulations. In our analysis, we concentrate on Sm–Sm distances in the range ~5.0–7.2 Å, corresponding to Sm atomsmore » in the second and third shells of Sm-centred clusters. We discover a number of empirical rules characterising the evolution of Sm networks from the liquid and amorphous states to associated metastable crystalline phases experimentally observed in the initial stages of devitrification of different amorphous samples. As direct simulation of glass formation is difficult because of the vast difference between experimental quench rates and what is achievable on the computer, we hope these rules will be helpful in building a better picture of structural evolution during glass formation as well as a more detailed description of phase selection and growth during devitrification.« less

A comparative study of Sm networks in Al-10 at.%Sm glass and associated crystalline phases

DOE PAGES

Lv, Xiaobao; Ye, Zhuo; Sun, Yang; ...

2018-04-03

Here, the Al–Sm system is selected as a model system to study the transition process from liquid and amorphous to crystalline states. In recent work, we have shown that, in addition to long-range translational periodicity, crystal structures display well-defined short-range local atomic packing motifs that transcends liquid, amorphous and crystalline states. In this paper, we investigate the longer range spatial packing of these short-range motifs by studying the interconnections of Sm–Sm networks in different amorphous and crystalline samples obtained from molecular dynamics simulations. In our analysis, we concentrate on Sm–Sm distances in the range ~5.0–7.2 Å, corresponding to Sm atomsmore » in the second and third shells of Sm-centred clusters. We discover a number of empirical rules characterising the evolution of Sm networks from the liquid and amorphous states to associated metastable crystalline phases experimentally observed in the initial stages of devitrification of different amorphous samples. As direct simulation of glass formation is difficult because of the vast difference between experimental quench rates and what is achievable on the computer, we hope these rules will be helpful in building a better picture of structural evolution during glass formation as well as a more detailed description of phase selection and growth during devitrification.« less

Amelogenin-assisted ex vivo remineralization of human enamel: effects of supersaturation degree and fluoride concentration

PubMed Central

Fan, Yuwei; Nelson, James R.; Alvarez, Jason R.; Hagan, Joseph; Berrier, Allison; Xu, Xiaoming

2011-01-01

The formation of organized nanocrystals that resemble enamel is crucial for successful enamel remineralization. Calcium, phosphate and fluoride ions and amelogenin are important ingredients for the formation of organized hydroxyapatite (HAP) crystals in vitro. However, the effects of these remineralization agents on the enamel crystal morphology have not been thoroughly studied. The objective of this study was to investigate the effects of fluoride ions, supersaturation degree and amelogenin on the crystal morphology and organization of ex vivo remineralized human enamel. Extracted third molars were sliced thin and acid-etched to provide the enamel surface for immersion in different remineralization solutions. The crystal morphology and mineral phase of the remineralized enamel surface were analyzed by FE-SEM, ATR-FTIR and XRD. The concentration of fluoride and supersaturation degree of hydroxyapatite had significant effects on the crystal morphology and crystal organization, which varied from plate-like loose crystals to rod-like densely packed nanocrystal arrays. Densely packed arrays of fluoridated hydroxyapatite nanorods were observed under the following conditions: σ(HAP) = 10.2±2.0 with fluoride 1.5±0.5 mg/L and amelogenin 40±10 µg/mL, pH 6.8±0.4. A phase diagram summarized the conditions that form dense or loose hydroxyapatite nanocrystal structures. This study provides the basis for the development of novel dental materials for caries management. PMID:21256987

Avogadro: an advanced semantic chemical editor, visualization, and analysis platform

PubMed Central

2012-01-01

Background The Avogadro project has developed an advanced molecule editor and visualizer designed for cross-platform use in computational chemistry, molecular modeling, bioinformatics, materials science, and related areas. It offers flexible, high quality rendering, and a powerful plugin architecture. Typical uses include building molecular structures, formatting input files, and analyzing output of a wide variety of computational chemistry packages. By using the CML file format as its native document type, Avogadro seeks to enhance the semantic accessibility of chemical data types. Results The work presented here details the Avogadro library, which is a framework providing a code library and application programming interface (API) with three-dimensional visualization capabilities; and has direct applications to research and education in the fields of chemistry, physics, materials science, and biology. The Avogadro application provides a rich graphical interface using dynamically loaded plugins through the library itself. The application and library can each be extended by implementing a plugin module in C++ or Python to explore different visualization techniques, build/manipulate molecular structures, and interact with other programs. We describe some example extensions, one which uses a genetic algorithm to find stable crystal structures, and one which interfaces with the PackMol program to create packed, solvated structures for molecular dynamics simulations. The 1.0 release series of Avogadro is the main focus of the results discussed here. Conclusions Avogadro offers a semantic chemical builder and platform for visualization and analysis. For users, it offers an easy-to-use builder, integrated support for downloading from common databases such as PubChem and the Protein Data Bank, extracting chemical data from a wide variety of formats, including computational chemistry output, and native, semantic support for the CML file format. For developers, it can be easily extended via a powerful plugin mechanism to support new features in organic chemistry, inorganic complexes, drug design, materials, biomolecules, and simulations. Avogadro is freely available under an open-source license from http://avogadro.openmolecules.net. PMID:22889332

Avogadro: an advanced semantic chemical editor, visualization, and analysis platform.

PubMed

Hanwell, Marcus D; Curtis, Donald E; Lonie, David C; Vandermeersch, Tim; Zurek, Eva; Hutchison, Geoffrey R

2012-08-13

The Avogadro project has developed an advanced molecule editor and visualizer designed for cross-platform use in computational chemistry, molecular modeling, bioinformatics, materials science, and related areas. It offers flexible, high quality rendering, and a powerful plugin architecture. Typical uses include building molecular structures, formatting input files, and analyzing output of a wide variety of computational chemistry packages. By using the CML file format as its native document type, Avogadro seeks to enhance the semantic accessibility of chemical data types. The work presented here details the Avogadro library, which is a framework providing a code library and application programming interface (API) with three-dimensional visualization capabilities; and has direct applications to research and education in the fields of chemistry, physics, materials science, and biology. The Avogadro application provides a rich graphical interface using dynamically loaded plugins through the library itself. The application and library can each be extended by implementing a plugin module in C++ or Python to explore different visualization techniques, build/manipulate molecular structures, and interact with other programs. We describe some example extensions, one which uses a genetic algorithm to find stable crystal structures, and one which interfaces with the PackMol program to create packed, solvated structures for molecular dynamics simulations. The 1.0 release series of Avogadro is the main focus of the results discussed here. Avogadro offers a semantic chemical builder and platform for visualization and analysis. For users, it offers an easy-to-use builder, integrated support for downloading from common databases such as PubChem and the Protein Data Bank, extracting chemical data from a wide variety of formats, including computational chemistry output, and native, semantic support for the CML file format. For developers, it can be easily extended via a powerful plugin mechanism to support new features in organic chemistry, inorganic complexes, drug design, materials, biomolecules, and simulations. Avogadro is freely available under an open-source license from http://avogadro.openmolecules.net.

Beta-hairpin formation in aqueous solution and in the presence of trifluoroethanol: a (1)H and (13)C nuclear magnetic resonance conformational study of designed peptides.

PubMed

Santiveri, Clara M; Pantoja-Uceda, David; Rico, Manuel; Jiménez, M Angeles

2005-10-15

In order to check our current knowledge on the principles involved in beta-hairpin formation, we have modified the sequence of a 3:5 beta-hairpin forming peptide with two different purposes, first to increase the stability of the formed 3:5 beta-hairpin, and second to convert the 3:5 beta-hairpin into a 2:2 beta-hairpin. The conformational behavior of the designed peptides was investigated in aqueous solution and in 30% trifluoroethanol (TFE) by analysis of the following nuclear magnetic resonance (NMR) parameters: nuclear Overhauser effect (NOE) data, and C(alpha)H, (13)C(alpha), and (13)C(beta) conformational shifts. From the differences in the ability to adopt beta-hairpin structures in these peptides, we have arrived to the following conclusions: (i) beta-Hairpin population increases with the statistical propensity of residues to occupy each turn position. (ii) The loop length, and in turn, the beta-hairpin type, can be modified as a function of the type of turn favored by the loop sequence. These two conclusions reinforce previous results about the importance of beta-turn sequence in beta-hairpin folding. (iii) Side-chain packing on each face of the beta-sheet may play a major role in beta-hairpin stability; hence simplified analysis in terms of isolated pair interactions and intrinsic beta-sheet propensities is insufficient. (iv) Contributions to beta-hairpin stability of turn and strand sequences are not completely independent. (v) The burial of hydrophobic surface upon beta-hairpin formation that, in turn, depends on side-chain packing also contributes to beta-hairpin stability. (vi) As previously observed, TFE stabilizes beta-hairpin structures, but the extent of the contribution of different factors to beta-hairpin formation is sometimes different in aqueous solution and in 30% TFE. (c) 2005 Wiley Periodicals, Inc. Biopolymers 79: 150-162, 2005.

Temperature-Triggered Protein Adsorption on Polymer-Coated Nanoparticles in Serum.

PubMed

Koshkina, Olga; Lang, Thomas; Thiermann, Raphael; Docter, Dominic; Stauber, Roland H; Secker, Christian; Schlaad, Helmut; Weidner, Steffen; Mohr, Benjamin; Maskos, Michael; Bertin, Annabelle

2015-08-18

The protein corona, which forms on the nanoparticle's surface in most biological media, determines the nanoparticle's physicochemical characteristics. The formation of the protein corona has a significant impact on the biodistribution and clearance of nanoparticles in vivo. Therefore, the ability to influence the formation of the protein corona is essential to most biomedical applications, including drug delivery and imaging. In this study, we investigate the protein adsorption on nanoparticles with a hydrodynamic radius of 30 nm and a coating of thermoresponsive poly(2-isopropyl-2-oxazoline) in serum. Using multiangle dynamic light scattering (DLS) we demonstrate that heating of the nanoparticles above their phase separation temperature induces the formation of agglomerates, with a hydrodynamic radius of 1 μm. In serum, noticeably stronger agglomeration occurs at lower temperatures compared to serum-free conditions. Cryogenic transmission electron microscopy (cryo-TEM) revealed a high packing density of agglomerates when serum was not present. In contrast, in the presence of serum, agglomerated nanoparticles were loosely packed, indicating that proteins are intercalated between them. Moreover, an increase in protein content is observed upon heating, confirming that protein adsorption is induced by the alteration of the surface during phase separation. After cooling and switching the surface back, most of the agglomerates were dissolved and the main fraction returned to the original size of approximately 30 nm as shown by asymmetrical flow-field flow fractionation (AF-FFF) and DLS. Furthermore, the amounts of adsorbed proteins are similar before and after heating the nanoparticles to above their phase-separation temperature. Overall, our results demonstrate that the thermoresponsivity of the polymer coating enables turning the corona formation on nanoparticles on and off in situ. As the local heating of body areas can be easily done in vivo, the thermoresponsive coating could potentially be used to induce the agglomeration of nanoparticles and proteins and the accumulation of nanoparticles in a targeted body region.

Formation processes of sea ice floe size distribution in the interior pack and its relationship to the marginal ice zone off East Antarctica

NASA Astrophysics Data System (ADS)

Toyota, Takenobu; Kohout, Alison; Fraser, Alexander D.

2016-09-01

To understand the behavior of the Seasonal Ice Zone (SIZ), which is composed of sea-ice floes of various sizes, knowledge of the floe size distribution (FSD) is important. In particular, FSD in the Marginal Ice Zone (MIZ), controlled by wave-ice interaction, plays an important role in determining the retreating rates of sea-ice extent on a global scale because the cumulative perimeter of floes enhances melting. To improve the understanding of wave-ice interaction and subsequent effects on FSD in the MIZ, FSD measurements were conducted off East Antarctica during the second Sea Ice Physics and Ecosystems eXperiment (SIPEX-2) in late winter 2012. Since logistical reasons limited helicopter operations to two interior ice regions, FSD in the interior ice region was determined using a combination of heli-photos and MODIS satellite visible images. The possible effect of wave-ice interaction in the MIZ was examined by comparison with past results obtained in the same MIZ, with our analysis showing: (1) FSD in the interior ice region is basically scale invariant for both small- (<100 m) and large- (>1 km) scale regimes; (2) although fractal dimensions are quite different between these two regimes, they are both rather close to that in the MIZ; and (3) for floes <100 m in diameter, a regime shift which appeared at 20-40 m in the MIZ is absent. These results indicate that one role of wave-ice interaction is to modulate the FSD that already exists in the interior ice region, rather than directly determine it. The possibilities of floe-floe collisions and storm-induced lead formation are considered as possible formation processes of FSD in the interior pack.

Consumer acceptability and understanding of front-of-pack nutrition labels.

PubMed

Mejean, C; Macouillard, P; Péneau, S; Hercberg, S; Castetbon, K

2013-10-01

Front-of-pack (FOP) nutrition labelling has been proposed as a tool for helping consumers make healthy choices. Before determining its effects on consumer behaviour, factors involved in its use must be elucidated, i.e. understanding and acceptability on the part of the consumer. Among five FOP labels, we sought to determine which formats were most easily understood and accepted by a large sample of adults. Among 39 370 adults who participated in the French Nutrinet-Santé cohort study, understanding and indicators of acceptability (attitude, liking, visual attractiveness and perceived cognitive workload) were measured for five FOP labels: The currently used 'multiple traffic lights' (MTL) and 'simple traffic lights' (STL), and the 'colour range' logo (CR), the 'green tick' and the PNNS logo. We investigated the contribution of the different elements to consumer perception of FOP labels using multiple correspondence analyses. Over half of the sample population showed a high level of understanding and perceived no discomfort in terms of the different logos. Label formats were positioned along an acceptability gradient ranging from acceptance to rejection, consisting of 'liking', 'attractiveness' and indicators of perceived cognitive workload. MTL was significantly more often liked and was viewed as reliable and informative. MTL, STL and the green tick performed better than the CR and PNNS logos in terms of ease of identification and comprehension. CR was clearly the least appreciated and it had the most complex format. Consumers prefer FOP labels which give complete, reliable and simplified information on the nutrient quality of foods. © 2013 The Authors Journal of Human Nutrition and Dietetics © 2013 The British Dietetic Association Ltd.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Maughan, Annalise E.; Ganose, Alex M.; Bordelon, Mitchell M.

Vacancy-ordered double perovskites of the general formula, A2BX6, are a family of perovskite derivatives composed of a face-centered lattice of nearly isolated [BX6] units with A-site cations occupying the cuboctahedral voids. Despite the presence of isolated octahedral units, the close-packed iodide lattice provides significant electronic dispersion, such that Cs2SnI6 has recently been explored for applications in photovoltaic devices. To elucidate the structure-property relationships of these materials, we have synthesized the solid solution Cs2Sn1-xTexI6. However, even though tellurium substitution increases electronic dispersion via closer I-I contact distances, the substitution experimentally yields insulating behavior from a significant decrease in carrier concentration andmore » mobility. Density functional calculations of native defects in Cs2SnI6 reveal that iodine vacancies exhibit a low enthalpy of formation and the defect energy level is a shallow donor to the conduction band, rendering the material tolerant to these defect states. The increased covalency of Te-I bonding renders the formation of iodine vacancy states unfavorable, and is responsible for the reduction in conductivity upon Te substitution. Additionally, Cs2TeI6 is intolerant to the formation of these defects, as the defect level occurs deep within the band gap and thus localizes potential mobile charge carriers. In these vacancy-ordered double perovskites, the close-packed lattice of iodine provides significant electronic dispersion, while the interaction of the B- and X-site ions dictates the properties as they pertain to electronic structure and defect tolerance. This simplified perspective -- based on extensive experimental and theoretical analysis -- provides a platform from which to understand structure-property relationships in functional perovskite halides.« less

Formation of Low Symmetry Ordered Phases in Block Polymer Melts

NASA Astrophysics Data System (ADS)

Bates, Frank

Until recently the phase behavior of asymmetric AB diblock copolymers in the melt state was universally accepted as a solved problem: spherical domains packed on a body centered cubic (BCC) lattice. Recent experiments with low molecular weight diblocks have upended this picture, beginning with the discovery of the Frank-Kasper sigma phase in poly(isoprene)- b-poly(lactide) (PI-PLA) followed recently by the identification of a dodecagonal quasicrystal phase (DDQC) as a metastable state that evolves from the supercooled disordered liquid. Self-consistent mean-field theory shows that introducing conformational asymmetry (bA >bB where b is the statistical segment length) opens a window in the phase portrait at fA <<1/2 that supports the formation of various low symmetry ordered phases. However, contrary to the widely accepted mean-field picture, the disordered state near the order-disorder transition (ODT) is highly structured and rapid cooling of this micellar fluid several tens of degrees below the ODT temperature arrests macromolecular chain exchange transitioning the material from an ergodic to non-ergodic state. We have explored the evolution of order following such temperature quenches and during subsequent reheating using synchrotron small-angle X-ray scattering (SAXS) revealing surprising analogies with the behavior of metal alloys. This presentation will associate the formation of ordered low symmetry phases with the concept of sphericity, the tendency for the self-assembled nanoparticles to be spherical in competition with the constraints imposed by periodic and aperiodic packing without voids and subject to the condition of incompressibility. Supported by NSF-DMR-1104368. This work was conducted in collaboration with Kyungtae Kim, Morgan Schulze, Akash Arora, Ronald Lewis, Timothy Gillard, Sangwoo Lee, Kevin Dorfman and Marc Hillmyer.

Mineralogical signatures of stone formation mechanisms.

PubMed

Gower, Laurie B; Amos, Fairland F; Khan, Saeed R

2010-08-01

The mechanisms involved in biomineralization are modulated through interactions with organic matrix. In the case of stone formation, the role of the organic macromolecules in the complex urinary environment is not clear, but the presence of mineralogical 'signatures' suggests that some aspects of stone formation may result from a non-classical crystallization process that is induced by acidic proteins. An amorphous precursor has been detected in many biologically controlled mineralization reactions, which is thought to be regulated by non-specific interactions between soluble acidic proteins and mineral ions. Using in vitro model systems, we find that a liquid-phase amorphous mineral precursor induced by acidic polypeptides can lead to crystal textures that resemble those found in Randall's plaque and kidney stones. This polymer-induced liquid-precursor process leads to agglomerates of coalesced mineral spherules, dense-packed spherulites with concentric laminations, mineral coatings and 'cements', and collagen-associated mineralization. Through the use of in vitro model systems, the mechanisms involved in the formation of these crystallographic features may be resolved, enhancing our understanding of the potential role(s) that proteins play in stone formation.

Different Effect of Co on the Formation of Topologically Close-Packed Phases in Ni-Cr-Mo and Ni-Cr-Re Alloys

NASA Astrophysics Data System (ADS)

Shi, Qianying; An, Ning; Huo, Jiajie; Ding, Xianfei; Zheng, Yunrong; Feng, Qiang

2017-11-01

In current study, two sets of Ni-based alloys (Ni-Cr-Mo and Ni-Cr-Re series) containing 0 to 15 at. pct of Co addition were investigated to understand the formation behavior of TCP phases. Significant difference on the formation behavior of TCP phases and corresponding Co effect was found in two series alloys. TCP precipitates ( P and µ phase) were observed in both grain interiors and boundaries in Ni-Cr-Mo series alloys. Higher levels of Co addition increased the supersaturation of Mo in the γ matrix, which explained that Co addition promoted µ phase formation. In contrast, the TCP precipitates ( σ phase) formed by the manner of discontinuous precipitation transformation in the grain boundaries in Ni-Cr-Re series alloys. More Co additions suppressed the formation of σ phase, which was mainly attributed to the decreased supersaturation of Re in thermodynamically metastable γ matrix. The information obtained from simplified alloy systems in this study is helpful for the design of multicomponent Ni-based superalloys.

Synthesis, structural characterization, Hirshfeld surface analysis and spectroscopic studies of cadmium (II) chloride complex with 4-hydroxy-1-methylpiperidine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soudani, S.; Ferretti, V.; Jelsch, C.

The chemical preparation, crystal structure, Hirshfeld surface analysis and spectroscopic characterization of the novel cadmium (II) 4-hydroxy-1-methylpiperidine complex, Cd{sub 4}Cl{sub 10}(C{sub 6}H{sub 14}NO){sub 2}·2H{sub 2}O, have been reported. The atomic arrangement can be described as built up by an anionic framework, formed by edge sharing CdCl{sub 6} and CdCl{sub 5}O octahedral linear chains spreading along the a-axis. These chains are interconnected by water molecules via O–H⋯Cl and O–H⋯O hydrogen bonds to form layers parallel to (011) plane. The organic cations are inserted between layers through C–H⋯Cl hydrogen bonds. Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis revealsmore » that the H{sub C}⋯Cl and H{sub C}⋯H{sub C} intermolecular interactions are the most abundant contacts of the organic cation in the crystal packing. The statistical analysis of crystal contacts reveals the driving forces in the packing formation. The {sup 13}C and {sup 15}N CP-MAS NMR spectra are in agreement with the X-ray structure. The vibrational absorption bands were identified by infrared spectroscopy. DFT calculations allowed the attribution of the NMR peaks and of the IR bands.« less

NOXclass: prediction of protein-protein interaction types.

PubMed

Zhu, Hongbo; Domingues, Francisco S; Sommer, Ingolf; Lengauer, Thomas

2006-01-19

Structural models determined by X-ray crystallography play a central role in understanding protein-protein interactions at the molecular level. Interpretation of these models requires the distinction between non-specific crystal packing contacts and biologically relevant interactions. This has been investigated previously and classification approaches have been proposed. However, less attention has been devoted to distinguishing different types of biological interactions. These interactions are classified as obligate and non-obligate according to the effect of the complex formation on the stability of the protomers. So far no automatic classification methods for distinguishing obligate, non-obligate and crystal packing interactions have been made available. Six interface properties have been investigated on a dataset of 243 protein interactions. The six properties have been combined using a support vector machine algorithm, resulting in NOXclass, a classifier for distinguishing obligate, non-obligate and crystal packing interactions. We achieve an accuracy of 91.8% for the classification of these three types of interactions using a leave-one-out cross-validation procedure. NOXclass allows the interpretation and analysis of protein quaternary structures. In particular, it generates testable hypotheses regarding the nature of protein-protein interactions, when experimental results are not available. We expect this server will benefit the users of protein structural models, as well as protein crystallographers and NMR spectroscopists. A web server based on the method and the datasets used in this study are available at http://noxclass.bioinf.mpi-inf.mpg.de/.

Structural, crystal structure, Hirshfeld surface analysis and physicochemical studies of a new chlorocadmate template by 1-(2-hydroxyethyl)piperazine

NASA Astrophysics Data System (ADS)

Soudani, S.; Jeanneau, E.; Jelsch, C.; Lefebvre, F.; Ben Nasr, C.

2016-11-01

The synthesis, crystal structure and spectroscopic characterization of a new chlorocadmate template by the 1-(2-hydroxyethyl)piperazine ligand are reported. In the atomic arrangement, the CdCl5O entities are deployed in corrugated rows along the a-axis at y = 1/4 and y = 3/4 to form layers parallel to the (a,b) plane. In these crystals, piperazinediium cations are in a chair conformation and are inserted between these layers through Nsbnd H⋯Cl, Csbnd H⋯Cl, Osbnd H⋯Cl and Nsbnd H⋯O hydrogen bonds to form infinite three-dimensional network. Investigation of intermolecular interactions and crystal packing via Hirshfeld surface analysis reveals that H⋯Cl and Csbnd H⋯Hsbnd C intermolecular interactions are the most abundant contacts of the organic cation in the crystal packing. The crystal contacts enrichments reveals that, the Cd++ … Cl- salt bridges, the Cd⋯O complexation and Osbnd H⋯Cl- and Nsbnd H⋯Cl-strong H-bonds are the driving forces in the packing formation. The presence of twelve independent chloride anions and four organic cation in the asymmetric unit allowed comparing their contact propensities. The 13C and 15N CP-MAS NMR spectra are in agreement with the X-ray structure. Additional characterization of this compound has also been performed by IR spectroscopy.

High resolution and image processing of otoconia matrix

NASA Technical Reports Server (NTRS)

Fermin, C. D.

1993-01-01

This study was designed to investigate patterns of fibrils organization in histochemically stained otoconia. Transmission electron microscope and video imaging were used. These data indicate that otoconia of the chick (Gallus domesticus) inner ear may have central cores in vivo. The data also show that the ultrastructural organization of fibrils fixed with aldehydes and histochemical stains follows trajectories that conform to the hexagonal shape of otoconia. These changes in direction may contribute to the formation of a central core. The existence of central cores is important for the in vivo buoyancy of otoconia. Packing of fibrils is tighter after phosphotungstic acid (PTA) stained otoconia than with other histochemical stains, which usually produce looser packing of fibrils and seemingly larger central core. TEM of tilted and untilted material showed that turning of fibrils occurs at the points where the face angles of otoconia form and where central cores exist. Video image processing of the images allowed reconstructing a template which, if assumed to repeat and change trajectories, would fit the pattern of fibrils seen in fixed otoconia. Since it is highly unlikely that aldehyde primary fixation or PTA stain caused such drastic change in the direction of fibrils, the template derived from these results may closely approximate patterns of otoconia fibrils packing in vivo. However, if the above is correct, the perfect crystallographic diffraction pattern of unfixed otoconia do not correspond to patterns of fixed fibrils.

Vertical profiling of aerosol particles and trace gases over the central Arctic Ocean during summer

NASA Astrophysics Data System (ADS)

Kupiszewski, P.; Leck, C.; Tjernström, M.; Sjogren, S.; Sedlar, J.; Graus, M.; Müller, M.; Brooks, B.; Swietlicki, E.; Norris, S.; Hansel, A.

2013-04-01

Unique measurements of vertical size resolved aerosol particle concentrations, trace gas concentrations and meteorological data were obtained during the Arctic Summer Cloud Ocean Study (ASCOS, http://www.ascos.se), an International Polar Year project aimed at establishing the processes responsible for formation and evolution of low-level clouds over the high Arctic summer pack ice. The experiment was conducted from onboard the Swedish icebreaker Oden, and provided both ship- and helicopter-based measurements. This study focuses on the vertical helicopter profiles and onboard measurements obtained during a three-week period when Oden was anchored to a drifting ice floe, and sheds light on the characteristics of Arctic aerosol particles and their distribution throughout the lower atmosphere. Distinct differences in aerosol particle characteristics within defined atmospheric layers are identified. Near the surface (lowermost couple hundred meters), transport from the marginal ice zone (MIZ), if sufficiently short (less than ca. 2 days), condensational growth and cloud-processing develop the aerosol population. During two of the four representative periods defined in this study, such influence is shown. At altitudes above about 1 km, long-range transport occurs frequently. However, only infrequently does large-scale subsidence descend such air masses to become entrained into the mixed layer in the high Arctic, and therefore they are unlikely to directly influence low-level stratiform cloud formation. Nonetheless, long-range transport plumes can influence the radiative balance of the PBL by influencing formation and evolution of higher clouds, as well as through precipitation transport of particles downwards. New particle formation was occasionally observed, particularly in the near-surface layer. We hypothesize that the origin of these ultrafine particles can be from biological processes, both primary and secondary, within the open leads between the pack ice and/or along the MIZ. In general, local sources, in combination with upstream boundary layer transport of precursor gases from the MIZ, are suggested to constitute the origin of CCN particles and thus be of importance for the formation of interior Arctic low level clouds during summer, and subsequently, through cloud influences, on the melting and freezing of sea ice.

Vertical profiling of aerosol particles and trace gases over the central Arctic Ocean during summer

NASA Astrophysics Data System (ADS)

Kupiszewski, P.; Leck, C.; Tjernström, M.; Sjogren, S.; Sedlar, J.; Graus, M.; Müller, M.; Brooks, B.; Swietlicki, E.; Norris, S.; Hansel, A.

2013-12-01

Unique measurements of vertical size-resolved aerosol particle concentrations, trace gas concentrations and meteorological data were obtained during the Arctic Summer Cloud Ocean Study (ASCOS, www.ascos.se), an International Polar Year project aimed at establishing the processes responsible for formation and evolution of low-level clouds over the high Arctic summer pack ice. The experiment was conducted from on board the Swedish icebreaker Oden, and provided both ship- and helicopter-based measurements. This study focuses on the vertical helicopter profiles and onboard measurements obtained during a three-week period when Oden was anchored to a drifting ice floe, and sheds light on the characteristics of Arctic aerosol particles and their distribution throughout the lower atmosphere. Distinct differences in aerosol particle characteristics within defined atmospheric layers are identified. Within the lowermost couple hundred metres, transport from the marginal ice zone (MIZ), condensational growth and cloud processing develop the aerosol population. During two of the four representative periods defined in this study, such influence is shown. At altitudes above about 1 km, long-range transport occurs frequently. However, only infrequently does large-scale subsidence descend such air masses to become entrained into the mixed layer in the high Arctic, and therefore long-range transport plumes are unlikely to directly influence low-level stratiform cloud formation. Nonetheless, such plumes can influence the radiative balance of the planetary boundary layer (PBL) by influencing formation and evolution of higher clouds, as well as through precipitation transport of particles downwards. New particle formation was occasionally observed, particularly in the near-surface layer. We hypothesize that the origin of these ultrafine particles could be in biological processes, both primary and secondary, within the open leads between the pack ice and/or along the MIZ. In general, local sources, in combination with upstream boundary-layer transport of precursor gases from the MIZ, are considered to constitute the origin of cloud condensation nuclei (CCN) particles and thus be of importance for the formation of interior Arctic low-level clouds during summer, and subsequently, through cloud influences, for the melting and freezing of sea ice.

Effect of packing method on the randomness of disc packings

NASA Astrophysics Data System (ADS)

Zhang, Z. P.; Yu, A. B.; Oakeshott, R. B. S.

1996-06-01

The randomness of disc packings, generated by random sequential adsorption (RSA), random packing under gravity (RPG) and Mason packing (MP) which gives a packing density close to that of the RSA packing, has been analysed, based on the Delaunay tessellation, and is evaluated at two levels, i.e. the randomness at individual subunit level which relates to the construction of a triangle from a given edge length distribution and the randomness at network level which relates to the connection between triangles from a given triangle frequency distribution. The Delaunay tessellation itself is also analysed and its almost perfect randomness at the two levels is demonstrated, which verifies the proposed approach and provides a random reference system for the present analysis. It is found that (i) the construction of a triangle subunit is not random for the RSA, MP and RPG packings, with the degree of randomness decreasing from the RSA to MP and then to RPG packing; (ii) the connection of triangular subunits in the network is almost perfectly random for the RSA packing, acceptable for the MP packing and not good for the RPG packing. Packing method is an important factor governing the randomness of disc packings.

Particle packing from an earth science viewpoint

NASA Astrophysics Data System (ADS)

Rogers, C. D. F.; Dijkstra, T. A.; Smalley, I. J.

1994-04-01

Particle packings are relevant to many aspects of the Earth sciences, and there is a long history of the study of packings from an Earth science viewpoint. Packings have also been studied in connection with other subjects and disciplines. Allen (1982) produced a major review which provides a solid base for Earth science related studies. This review complements Allen's work and in particular focuses on advances in the study of random packings over the last ten years. Transitions from packing to packing may be as important as the packings themselves, and possibly easier to model. This paper places emphasis on certain neglected works, in particular Morrow and Graves (1969) and the packing transition envelope, Kahn (1956) and the measurement of packing parameters, Griffiths (1962) on packings in one-dimension, and Getis and Boots (1978) on packings in two dimensions. Certain packing problems are relevant to current areas of study including structure collapse in loess (hydroconsolidation), flowslides in very sensitive soils, wind erosion, jewel quality in opals and the structure and functions of sand dunes. The region where interparticle forces become active (particles < 200 μm) is considered and the implications for packing are examined.

ALPS - A LINEAR PROGRAM SOLVER

NASA Technical Reports Server (NTRS)

Viterna, L. A.

1994-01-01

Linear programming is a widely-used engineering and management tool. Scheduling, resource allocation, and production planning are all well-known applications of linear programs (LP's). Most LP's are too large to be solved by hand, so over the decades many computer codes for solving LP's have been developed. ALPS, A Linear Program Solver, is a full-featured LP analysis program. ALPS can solve plain linear programs as well as more complicated mixed integer and pure integer programs. ALPS also contains an efficient solution technique for pure binary (0-1 integer) programs. One of the many weaknesses of LP solvers is the lack of interaction with the user. ALPS is a menu-driven program with no special commands or keywords to learn. In addition, ALPS contains a full-screen editor to enter and maintain the LP formulation. These formulations can be written to and read from plain ASCII files for portability. For those less experienced in LP formulation, ALPS contains a problem "parser" which checks the formulation for errors. ALPS creates fully formatted, readable reports that can be sent to a printer or output file. ALPS is written entirely in IBM's APL2/PC product, Version 1.01. The APL2 workspace containing all the ALPS code can be run on any APL2/PC system (AT or 386). On a 32-bit system, this configuration can take advantage of all extended memory. The user can also examine and modify the ALPS code. The APL2 workspace has also been "packed" to be run on any DOS system (without APL2) as a stand-alone "EXE" file, but has limited memory capacity on a 640K system. A numeric coprocessor (80X87) is optional but recommended. The standard distribution medium for ALPS is a 5.25 inch 360K MS-DOS format diskette. IBM, IBM PC and IBM APL2 are registered trademarks of International Business Machines Corporation. MS-DOS is a registered trademark of Microsoft Corporation.

Maintenance of a functional higher order chromatin structure: The role of the nuclear matrix in normal and disease states

PubMed Central

Linnemann, Amelia K.; Krawetz, Stephen A.

2010-01-01

Summary The ordered packaging of DNA within the nucleus of somatic cells reflects a dynamic supportive structure that facilitates stable transcription interrupted by intermittent cycles of extreme condensation. This dynamic mode of packing and unpacking chromatin is intimately linked to the ability of the genome to specifically complex with both histones and non-histone proteins. Understanding the underlying mechanism that governs the formation of higher order chromatin structures is a key to understanding how local architecture modulates transcription. In part, the formation of these structures appears to be regulated through genomic looping that is dynamically mediated by attachment to the nuclear scaffold/matrix at S/MARs, i.e., Scaffold/Matrix Attachment Regions. Although the mechanism guiding the formation and use of these higher-ordered structures remains unknown, S/MARs continue to reveal a multitude of roles in development and the pathogenesis of disease. PMID:20948980

Maintenance of a functional higher order chromatin structure: The role of the nuclear matrix in normal and disease states.

PubMed

Linnemann, Amelia K; Krawetz, Stephen A

2009-01-01

The ordered packaging of DNA within the nucleus of somatic cells reflects a dynamic supportive structure that facilitates stable transcription interrupted by intermittent cycles of extreme condensation. This dynamic mode of packing and unpacking chromatin is intimately linked to the ability of the genome to specifically complex with both histones and non-histone proteins. Understanding the underlying mechanism that governs the formation of higher order chromatin structures is a key to understanding how local architecture modulates transcription. In part, the formation of these structures appears to be regulated through genomic looping that is dynamically mediated by attachment to the nuclear scaffold/matrix at S/MARs, i.e., Scaffold/Matrix Attachment Regions. Although the mechanism guiding the formation and use of these higher-ordered structures remains unknown, S/MARs continue to reveal a multitude of roles in development and the pathogenesis of disease.

Argus: A W-band 16-pixel focal plane array for the Green Bank Telescope

NASA Astrophysics Data System (ADS)

Devaraj, Kiruthika; Church, Sarah; Cleary, Kieran; Frayer, David; Gawande, Rohit; Goldsmith, Paul; Gundersen, Joshua; Harris, Andrew; Kangaslahti, Pekka; Readhead, Tony; Reeves, Rodrigo; Samoska, Lorene; Sieth, Matt; Voll, Patricia

2015-05-01

We are building Argus, a 16-pixel square-packed focal plane array that will cover the 75-115.3 GHz frequency range on the Robert C. Byrd Green Bank Telescope (GBT). The primary research area for Argus is the study of star formation within our Galaxy and nearby galaxies. Argus will map key molecules that trace star formation, including carbon monoxide (CO) and hydrogen cyanide (HCN). An additional key science area is astrochemistry, which will be addressed by observing complex molecules in the interstellar medium, and the study of formation of solar systems, which will be addressed by identifying dense pre-stellar cores and by observing comets in our solar system. Argus has a highly scalable architecture and will be a technology path finder for larger arrays. The array is modular in construction, which will allow easy replacement of malfunctioning and poorly performing components.

I Situ Structural Study of Underpotential Deposition and Electrocatalysis on GOLD(111) Electrodes

NASA Astrophysics Data System (ADS)

Chen, Chun-Hsien

This thesis work has studied systems of Bi, Pb, Ag, and Hg underpotential deposition (UPD) on Au(111) electrodes. The application of the atomic force microscope (AFM), the scanning tunneling microscope (STM), and the surface x-ray scattering (SXS) to these UPD studies has provided in situ measurements from which we investigate factors that determine UPD surface structures and correlate these structures with surface reactivity. For all the UPD systems in this thesis work, atomic level features of the electrode surface have been revealed. In the case of Pb UPD, Pb starts to deposit by forming islands which exhibit a hexagonal close packed structure of Pb adatoms, while, in the other systems, the UPD adatoms form open lattices. In the Bi and Pb studies, we correlate the activities of the modified surface toward electroreduction of H_2O_2 with the adlattice structures. A heterobimetallic bridge model for H_2O_2 on the surface could explain the enhanced reactivity. The full monolayers of Bi and Hg, rhombohedral metals, form rectangular lattice structures on the hexagonal Au(111) surfaces. The partial charge retention on the Bi and Hg adatom opens the adlayer structure when the coverage is less than a full monolayer. The structure of the first submonolayers of Ag UPD is electrolyte-dependent. The electrode surface exhibits 3 x 3 and 4 x 4 overlayer structures in solutions containing sulfate and nitrate, respectively. In perchloric acid another open structure is observed and a close-packed monolayer is formed in acetic acid. The different monolayer structures give rise to packing densities which correlate with electrolyte size. This implies that the anions participate in reducing metal ions.

Young adult smokers' perceptions of plain packs, numbered packs and pack inserts in Turkey: a focus group study.

PubMed

Mucan, Burcu; Moodie, Crawford

2017-11-09

The Turkish Government's 'National Tobacco Control Program 2015-2018' included plans to introduce plain packaging and also a ban on brand names on cigarette packs, allowing only assigned numbers on packs. We explored perceptions of these proposed measures, and also pack inserts with cessation messages, another novel way of using the packaging to communicate with consumers. Eight focus groups were conducted with 47 young adult smokers in Manisa and Kutahya (Turkey) in December 2016. Participants were shown three straight-edged plain cigarette packs, as required in Australia, and then three bevelled-edged plain packs, as permitted in the UK. They were then shown plain packs with numbers rather than brand names, and finally three pack inserts with messages encouraging quitting or offering tips on how to do so. Participants were asked about their perceptions of each. Plain packs were considered unappealing and off-putting, although the bevelled-edged packs were viewed more favourably than the straight-edged packs. Numbered packs were thought by some to diminish the appeal created by the brand name and potentially decrease interest among never smokers and newer smokers. Pack inserts were thought to have less of an impact than the on-pack warnings, but could potentially help discourage initiation and encourage cessation. That bevelled-edged plain packs were perceived more positively than straight-edged plain packs is relevant to countries planning to introduce plain packaging. The study provides a first insight into smokers' perceptions of a ban on brand names, which was perceived to reduce appeal among young people. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Tuning jammed frictionless disk packings from isostatic to hyperstatic.

PubMed

Schreck, Carl F; O'Hern, Corey S; Silbert, Leonardo E

2011-07-01

We perform extensive computational studies of two-dimensional static bidisperse disk packings using two distinct packing-generation protocols. The first involves thermally quenching equilibrated liquid configurations to zero temperature over a range of thermal quench rates r and initial packing fractions followed by compression and decompression in small steps to reach packing fractions φ(J) at jamming onset. For the second, we seed the system with initial configurations that promote micro- and macrophase-separated packings followed by compression and decompression to φ(J). Using these protocols, we generate more than 10(4) static packings over a wide range of packing fraction, contact number, and compositional and positional order. We find that disordered, isostatic packings exist over a finite range of packing fractions in the large-system limit. In agreement with previous calculations, the most dilute mechanically stable packings with φ min ≈ 0.84 are obtained for r > r*, where r* is the rate above which φ(J) is insensitive to rate. We further compare the structural and mechanical properties of isostatic versus hyperstatic packings. The structural characterizations include the contact number, several order parameters, and mixing ratios of the large and small particles. We find that the isostatic packings are positionally and compositionally disordered (with only small changes in a number of order parameters), whereas bond-orientational and compositional order increase strongly with contact number for hyperstatic packings. In addition, we calculate the static shear modulus and normal mode frequencies (in the harmonic approximation) of the static packings to understand the extent to which the mechanical properties of disordered, isostatic packings differ from partially ordered packings. We find that the mechanical properties of the packings change continuously as the contact number increases from isostatic to hyperstatic.

Mechanochemical Synthesis of Carbon Nanothread Single Crystals.

PubMed

Li, Xiang; Baldini, Maria; Wang, Tao; Chen, Bo; Xu, En-Shi; Vermilyea, Brian; Crespi, Vincent H; Hoffmann, Roald; Molaison, Jamie J; Tulk, Christopher A; Guthrie, Malcolm; Sinogeikin, Stanislav; Badding, John V

2017-11-15

Synthesis of well-ordered reduced dimensional carbon solids with extended bonding remains a challenge. For example, few single-crystal organic monomers react under topochemical control to produce single-crystal extended solids. We report a mechanochemical synthesis in which slow compression at room temperature under uniaxial stress can convert polycrystalline or single-crystal benzene monomer into single-crystalline packings of carbon nanothreads, a one-dimensional sp 3 carbon nanomaterial. The long-range order over hundreds of microns of these crystals allows them to readily exfoliate into fibers. The mechanochemical reaction produces macroscopic single crystals despite large dimensional changes caused by the formation of multiple strong, covalent C-C bonds to each monomer and a lack of reactant single-crystal order. Therefore, it appears not to follow a topochemical pathway, but rather one guided by uniaxial stress, to which the nanothreads consistently align. Slow-compression room-temperature synthesis may allow diverse molecular monomers to form single-crystalline packings of polymers, threads, and higher dimensional carbon networks.

Experimental investigation of a packed bed thermal energy storage system

NASA Astrophysics Data System (ADS)

Cascetta, Mario; Cau, Giorgio; Puddu, Pierpaolo; Serra, Fabio

2015-11-01

In this work experimental investigations on a thermal energy storage system with a solid material as storage media and air as heat transfer fluid will be presented. The experimental test rig, installed at the DIMCM of the University of Cagliari, consists of a carbon steel tank filled with freely poured alumina beads that allows investigations of heat transfer phenomena in packed beds. The aim of this work is to show the influence of the operating conditions and physical parameters on thermocline formation and, in particular, the thermal behaviour of the thermal energy storage for repeated charging and discharging cycles. Better charging efficiency is obtained for lower values of mass flow rate and maximum air temperature and for increasing aspect ratio. A decreasing influence of the metal wall with continuous operation is also highlighted. In conclusion, the analysis focuses on the thermal hysteresis phenomenon, which causes degradation of the thermocline and the reduction of the energy that can be stored by the accumulator as the repeated number of cycles increases.

On crystal versus fiber formation in dipeptide hydrogelator systems.

PubMed

Houton, Kelly A; Morris, Kyle L; Chen, Lin; Schmidtmann, Marc; Jones, James T A; Serpell, Louise C; Lloyd, Gareth O; Adams, Dave J

2012-06-26

Naphthalene dipeptides have been shown to be useful low-molecular-weight gelators. Here we have used a library to explore the relationship between the dipeptide sequence and the hydrogelation efficiency. A number of the naphthalene dipeptides are crystallizable from water, enabling us to investigate the comparison between the gel/fiber phase and the crystal phase. We succeeded in crystallizing one example directly from the gel phase. Using X-ray crystallography, molecular modeling, and X-ray fiber diffraction, we show that the molecular packing of this crystal structure differs from the structure of the gel/fiber phase. Although the crystal structures may provide important insights into stabilizing interactions, our analysis indicates a rearrangement of structural packing within the fibers. These observations are consistent with the fibrillar interactions and interatomic separations promoting 1D assembly whereas in the crystals the peptides are aligned along multiple axes, allowing 3D growth. This observation has an impact on the use of crystal structures to determine supramolecular synthons for gelators.

Effects of spatial separation on the growth of vertically aligned carbon nanofibers produced by plasma-enhanced chemical vapor deposition

NASA Astrophysics Data System (ADS)

Merkulov, Vladimir I.; Melechko, Anatoli V.; Guillorn, Michael A.; Lowndes, Douglas H.; Simpson, Michael L.

2002-01-01

Vertically aligned carbon nanofibers (VACNFs) with vastly different spacing were grown by catalytically controlled dc glow discharge chemical vapor deposition. Both densely packed VACNFs and essentially isolated VACNFs were studied using scanning electron microscopy and x-ray energy dispersive spectroscopy. The morphology and chemical composition of isolated VACNFs were found to have a strong dependence upon the growth conditions, in particular on the C2H2/NH3 gas mixture used. This is attributed to the sidewalls of isolated VACNFs being exposed to reactive species during growth. In contrast, the sidewalls of densely packed VACNFs were shielded by the neighboring VACNFs, so that their growth occurred mainly in the vertical direction, by diffusion of carbon through the catalyst nanoparticle and subsequent precipitation at the nanofiber/nanoparticle interface. These striking differences in the growth process result in the formation of flattened carbon nanostructures (carbon nanotriangles) and also are quite important for the realization of VACNF-based devices.

The impact of structural packaging design on young adult smokers' perceptions of tobacco products.

PubMed

Borland, Ron; Savvas, Steven; Sharkie, Fiona; Moore, Karen

2013-03-01

To examine the extent that novel cigarette pack shapes and openings have on smokers' perceptions of those packs and the cigarettes contained within. Using a web-based survey, 160 young adult ever-smokers (18-29 years) were shown computer images of plain packaged cigarette packs in five different shapes. This was followed by packs illustrating five different methods of opening. Brand (prestige or budget) and size of the health warnings (30% or 70% warning size) were between-subject conditions. Respondents ranked packs on attractiveness, perceived quality of the cigarettes contained within and extent that the pack distracted from health warnings. Ratings of attractiveness and perceived quality were significantly associated in both substudies, but tendency to distract from warnings was more independent. Significant differences were found between the pack shapes on attractiveness, perceived quality and distraction from warnings. Standard, 2×10 and 4×5 packs were ranked less attractive than Bevelled and Rounded packs. 2×10 and 4×5 packs were also perceived as lower quality than Bevelled and Rounded packs. The Standard pack was less distracting to health warnings than all other shapes except the 2×10 pack. Pack openings were perceived as different on quality of cigarettes contained and extent of distraction to warnings. The Standard Flip-top was rated significantly lower in distracting from warnings than all other openings. Pack shape and pack opening affect ever-smokers' perceptions of the packs and the cigarettes they contain. This means that they have the potential to create appeal and differentiate products and thus should be regulated.

Structure and decomposition of the silver formate Ag(HCO{sub 2})

DOE Office of Scientific and Technical Information (OSTI.GOV)

Puzan, Anna N., E-mail: anna_puzan@mail.ru; Baumer, Vyacheslav N.; Mateychenko, Pavel V.

Crystal structure of the silver formate Ag(HCO{sub 2}) has been determined (orthorhombic, sp.gr. Pccn, a=7.1199(5), b=10.3737(4), c=6.4701(3)Å, V=477.88(4) Å{sup 3}, Z=8). The structure contains isolated formate ions and the pairs Ag{sub 2}{sup 2+} which form the layers in (001) planes (the shortest Ag–Ag distances is 2.919 in the pair and 3.421 and 3.716 Å between the nearest Ag atoms of adjacent pairs). Silver formate is unstable compound which decompose spontaneously vs time. Decomposition was studied using Rietveld analysis of the powder diffraction patterns. It was concluded that the diffusion of Ag atoms leads to the formation of plate-like metal particlesmore » as nuclei in the (100) planes which settle parallel to (001) planes of the silver formate matrix. - Highlights: • Silver formate Ag(HCO{sub 2}) was synthesized and characterized. • Layered packing of Ag-Ag pairs in the structure was found. • Decomposition of Ag(HCO{sub 2}) and formation of metal phase were studied. • Rietveld-refined micro-structural characteristics during decomposition reveal the space relationship between the matrix structure and forming Ag phase REPLACE with: Space relationship between the matrix structure and forming Ag phase.« less

Safety and effectiveness evaluation of a domestic peritoneal dialysis fluid packed in non-PVC bags: study protocol for a randomized controlled trial.

PubMed

Zhou, Jianhui; Cao, Xueying; Lin, Hongli; Ni, Zhaohui; He, Yani; Chen, Menghua; Zheng, Hongguang; Chen, Xiangmei

2015-12-29

Peritoneal dialysis is an important type of renal replacement therapy for uremic patients. In peritoneal dialysis, fluids fill in and flow out of the abdominal cavity three to five times per day. Usually, the fluid is packed in a polyvinyl chloride (PVC) bag. Safety concerns have arisen over di-(2-ethylhexyl) phthalate, which is essential in the formation of PVC materials. In 2011, the National Development and Reform Commission of China released a catalog of industrial structural adjustments, mandating the elimination of PVC bags for intravenous infusion and food containers. Although bags for peritoneal dialysis fluid were not included in the elimination list, several manufacturers began to develop new materials for fluid bags. HUAREN peritoneal dialysis fluid consists of the same electrolytes and buffer agent as in Baxter fluid, but is packed in bags that do not contain PVC. This multicenter randomized controlled trial was designed to compare peritoneal dialysis fluid packed in non-PVC-containing and PVC-containing bags. Further, the study sought to determine the proper dose of peritoneal dialysis fluid and the actual survival rates of Chinese patients undergoing peritoneal dialysis. The study participants are adults undergoing continuous ambulatory peritoneal dialysis for 30 days to 6 months. All eligible patients are randomized (1:1) to peritoneal dialysis with Baxter and HUAREN dialysis fluids (initial dose, 6 l/day), with dosages adjusted according to a unified protocol. The primary outcomes are the 1-, 2-, 3-, 4-, and 5-year overall survival rates. Secondary outcome measures include technique survival rates, reductions in estimated glomerular filtration rate, nutritional status, quality of life, cardiovascular events, medical costs and drop-out rates. Safety outcome measures include adverse events, changes in vital signs and laboratory parameters, peritonitis, allergies, and quality of products. This study is the first to evaluate the long-term safety and effectiveness of a non-PVC packed peritoneal dialysis fluid. The effects of plasticizer on patient long-term survival will be determined. The characteristics of Chinese patients undergoing peritoneal dialysis will be determined, including proper dose, technique survival rates, patient survival rates, and medical costs. Clinicaltrials.gov NCT01779557 .

The kinetics of rugby union scrummaging.

PubMed

Milburn, P D

1990-01-01

Two rugby union forward packs of differing ability levels were examined during scrummaging against an instrumented scrum machine. By systematically moving the front-row of the scrum along the scrum machine, kinetic data on each front-row forward could be obtained under all test conditions. Each forward pack was tested under the following scrummaging combinations: front-row only; front-row plus second-row; full scrum minus side-row, and full scrum. Data obtained from each scrum included the three orthogonal components of force at engagement and the sustained force applied by each front-row player. An estimate of sub-unit contributions was made by subtracting the total forward force on all three front-row players from the total for the complete scrum. Results indicated the primary role of the second-row appeared to be application of forward force. The back-row ('number eight') forward did not substantially contribute any additional forward force, and added only slightly to the lateral and vertical shear force experienced by the front-row. The side-row contributed an additional 20-27% to the forward force, but at the expense of increased vertical forces on all front-row forwards. Results of this investigation are discussed in relation to rule modification, rule interpretation and coaching.

In silico study of full-length amyloid beta 1-42 tri- and penta-oligomers in solution.

PubMed

Masman, Marcelo F; Eisel, Ulrich L M; Csizmadia, Imre G; Penke, Botond; Enriz, Ricardo D; Marrink, Siewert Jan; Luiten, Paul G M

2009-08-27

Amyloid oligomers are considered to play causal roles in the pathogenesis of amyloid-related degenerative diseases including Alzheimer's disease. Using MD simulation techniques, we explored the contributions of the different structural elements of trimeric and pentameric full-length Abeta1-42 aggregates in solution to their stability and conformational dynamics. We found that our models are stable at a temperature of 310 K, and converge toward an interdigitated side-chain packing for intermolecular contacts within the two beta-sheet regions of the aggregates: beta1 (residues 18-26) and beta2 (residues 31-42). MD simulations reveal that the beta-strand twist is a characteristic element of Abeta-aggregates, permitting a compact, interdigitated packing of side chains from neighboring beta-sheets. The beta2 portion formed a tightly organized beta-helix, whereas the beta1 portion did not show such a firm structural organization, although it maintained its beta-sheet conformation. Our simulations indicate that the hydrophobic core comprising the beta2 portion of the aggregate is a crucial stabilizing element in the Abeta aggregation process. On the basis of these structure-stability findings, the beta2 portion emerges as an optimal target for further antiamyloid drug design.

Formation of Nanoparticle Stripe Patterns via Flexible-Blade Flow Coating

NASA Astrophysics Data System (ADS)

Lee, Dong Yun; Kim, Hyun Suk; Parkos, Cassandra; Lee, Cheol Hee; Emrick, Todd; Crosby, Alfred

2011-03-01

We present the controlled formation of nanostripe patterns of nanoparticles on underlying substrates by flexible-blade flow coating. This technique exploits the combination of convective flow of confined nanoparticle solutions and programmed translation of a substrate to fabricate nanoparticle-polymer line assemblies with width below 300 nm, thickness of a single nanoparticle, and lengths exceeding 10 cm. We demonstrate how the incorporation of a flexible blade into this technique allows capillary forces to self-regulate the uniformity of convective flow processes across large lateral lengths. Furthermore, we exploit solvent mixture dynamics to enhance intra-assembly particle packing and dimensional range. This facile technique opens up a new paradigm for integration of nanoscale patterns over large areas for various applications.

An automated wide-field time-gated optically sectioning fluorescence lifetime imaging multiwell plate reader for high-content analysis of protein-protein interactions

NASA Astrophysics Data System (ADS)

Alibhai, Dominic; Kumar, Sunil; Kelly, Douglas; Warren, Sean; Alexandrov, Yuriy; Munro, Ian; McGinty, James; Talbot, Clifford; Murray, Edward J.; Stuhmeier, Frank; Neil, Mark A. A.; Dunsby, Chris; French, Paul M. W.

2011-03-01

We describe an optically-sectioned FLIM multiwell plate reader that combines Nipkow microscopy with wide-field time-gated FLIM, and its application to high content analysis of FRET. The system acquires sectioned FLIM images in <10 s/well, requiring only ~11 minutes to read a 96 well plate of live cells expressing fluorescent protein. It has been applied to study the formation of immature HIV virus like particles (VLPs) in live cells by monitoring Gag-Gag protein interactions using FLIM FRET of HIV-1 Gag transfected with CFP or YFP. VLP formation results in FRET between closely packed Gag proteins, as confirmed by our FLIM analysis that includes automatic image segmentation.

Formation and coarsening of near-surface Ga nanoparticles on SiN{sub x}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Canniff, J. C.; Jeon, S.; Huang, S.

2015-06-15

We have investigated the formation and coarsening of near-surface Ga nanoparticles (NPs) in SiN{sub x} using Ga{sup +} focused-ion-beam-irradiation of SiN{sub x}, followed by rapid thermal annealing. For surfaces with minimal curvature, diffusive growth is apparent, leading to nearly close packed arrays with NP diameters as small as 3 nm and densities as high as ∼4 × 10{sup 12} cm{sup −2}. The diffusive flux increases with annealing temperature, leading to NP coarsening by Ostwald ripening. For surfaces with increased curvature, diffusion towards the valleys also increases during annealing, leading to Ga NP coalescence and a bi-modal distribution of NP sizes.

Cigarette pack design and adolescent smoking susceptibility: a cross-sectional survey

PubMed Central

Ford, Allison; MacKintosh, Anne Marie; Moodie, Crawford; Richardson, Sol; Hastings, Gerard

2013-01-01

Objectives To compare adolescents’ responses to three different styles of cigarette packaging: novelty (branded packs designed with a distinctive shape, opening style or bright colour), regular (branded pack with no special design features) and plain (brown pack with a standard shape and opening and all branding removed, aside from brand name). Design Cross-sectional in-home survey. Setting UK. Participants Random location quota sample of 1025 never smokers aged 11–16 years. Main outcome measures Susceptibility to smoking and composite measures of pack appraisal and pack receptivity derived from 11 survey items. Results Mean responses to the three pack types were negative for all survey items. However, ‘novelty’ packs were rated significantly less negatively than the ‘regular’ pack on most items, and the novelty and regular packs were rated less negatively than the ‘plain’ pack. For the novelty packs, logistic regressions, controlling for factors known to influence youth smoking, showed that susceptibility was associated with positive appraisal and also receptivity. For example, those receptive to the innovative Silk Cut Superslims pack were more than four times as likely to be susceptible to smoking than those not receptive to this pack (AOR=4.42, 95% CI 2.50 to 7.81, p<0.001). For the regular pack, an association was found between positive appraisal and susceptibility but not with receptivity and susceptibility. There was no association with pack appraisal or receptivity for the plain pack. Conclusions Pack structure (shape and opening style) and colour are independently associated, not just with appreciation of and receptivity to the pack, but also with susceptibility to smoke. In other words, those who think most highly of novelty cigarette packaging are also the ones who indicate that they are most likely to go on to smoke. Plain packaging, in contrast, was found to directly reduce the appeal of smoking to adolescents. PMID:24056481

Stability Limits of Circumbinary Planets: Is There a Pile-up in the Kepler CBPs?

NASA Astrophysics Data System (ADS)

Quarles, B.; Satyal, S.; Kostov, V.; Kaib, N.; Haghighipour, N.

2018-04-01

The stability limit for circumbinary planets (CBPs) is not well defined and can depend on initial parameters defining either the planetary orbit and/or the inner binary orbit. We expand on the work of Holman & Wiegert (1999) to develop numerical tools for quick, easy, and accurate determination of the stability limit. The results of our simulations, as well as our numerical tools, are available to the community through Zenodo and GitHub, respectively. We employ a grid interpolation method based on ∼150 million full N-body simulations of initially circular, coplanar systems and compare to the nine known Kepler CBP systems. Using a formalism from planet packing studies, we find that 55% of the Kepler CBP systems allow for an additional equal-mass planet to potentially exist on an interior orbit relative to the observed planet. Therefore, we do not find strong evidence for a pile-up in the Kepler CBP systems and more detections are needed to adequately characterize the formation mechanisms for the CBP population. Observations from the Transiting Exoplanet Survey Satellite are expected to substantially increase the number of detections using the unique geometry of CBP systems, where multiple transits can occur during a single conjunction.

Initial development and performance evaluation of a process for formation of dense carbon by pyrolysis of methane

NASA Technical Reports Server (NTRS)

Noyes, G. P.; Cusick, R. J.

1985-01-01

The three steps in pyrolytic carbon formation are: (1) gaseous hydrocarbon polymerization and aromatic formation; (2) gas-phase condensation and surface adsorption/impingement of polyaromatic hydrocarbon; and (3) final dehydration to carbon. The structure of the carbon in the various stages of formation is examined. The apparatuses and experimental procedures for the pyrolysis of methane in a 60 cm long quartz reactor tube at temperatures ranging from 1400-1600 K are described. The percentage of carbon converted and its density are calculated and tabularly presented. The results reveal that dense carbon formation is maximized and soot eliminated by this procedure. It is observed that conversion efficiency depends on the composition of the inlet gas and conversion increases with increasing temperature. Based on the experimental data a three-man carbon reactor subsystem (CRS) is developed; the functions of the Sabatier Methanation Reactor, two carbon formation reactors and fluid handling components of the CRS are analyzed. The CRS forms 16 kg of carbon at a rate of 0.8 kg/day for 20 days in a two percent volume density quartz wool packing at temperature of 1500-1600 K.

7 CFR 51.310 - Packing requirements.

Code of Federal Regulations, 2011 CFR

2011-01-01

... STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged according to approved and... that apples are of the proper size for molds or cell compartments in which they are packed, and that...

7 CFR 51.310 - Packing requirements.

Code of Federal Regulations, 2012 CFR

2012-01-01

... STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged according to approved and... that apples are of the proper size for molds or cell compartments in which they are packed, and that...

Random three-dimensional jammed packings of elastic shells acting as force sensors

NASA Astrophysics Data System (ADS)

Jose, Jissy; van Blaaderen, Alfons; Imhof, Arnout

2016-06-01

In a jammed solid of granular particles, the applied stress is in-homogeneously distributed within the packing. A full experimental characterization requires measurement of all the interparticle forces, but so far such measurements are limited to a few systems in two and even fewer in three dimensions. Particles with the topology of (elastic) shells are good local force sensors as relatively large deformations of the shells result from relatively small forces. We recently introduced such fluorescent shells as a model granular system in which force distributions can be determined in three dimensions using confocal microscopy and quantitative image analysis. An interesting aspect about these shells that differentiates them from other soft deformable particles is their buckling behavior at higher compression. This leads to deformations that do not conserve the inner volume of the particle. Here we use this system to accurately measure the contact forces in a three-dimensional packing of shells subjected to a static anisotropic compression and to shear. At small deformations forces are linear, however, for a buckled contact, the restoring force is related to the amount of deformation by a square root law, as follows from the theory of elasticity of shells. Near the unjamming-jamming transition (point J ), we found the probability distribution of the interparticle forces P (f ) to decay nearly exponentially at large forces, with little evidence of long-range force chains in the packings. As the packing density is increased, the tail of the distribution was found to crossover to a Gaussian, in line with other experimental and simulation studies. Under a small shear strain, up to 0.216, applied at an extremely low shear rate, we observed a shear-induced anisotropy in both the pair correlation function and contact force network; however, no appreciable change was seen in the number of contacts per particle.

On the Functionality of Complex Intermetallics: Frustration, Chemical Pressure Relief, and Potential Rattling Atoms in Y11Ni60C6.

PubMed

Guo, Yiming; Fredrickson, Daniel C

2016-10-17

Intermetallic carbides provide excellent model systems for exploring how frustration can shape the structures and properties of inorganic materials. Combinations of several metals with carbon can be designed in which the formation of tetrahedrally close-packed (TCP) intermetallics conflicts with the C atoms' requirement of trigonal prismatic or octahedral coordination environments, as offered by the simple close-packings (SCP) of equally sized spheres. In this Article, we explore the driving forces that lead to the coexistence of these incompatible arrangements in the Yb 11 Ni 60 C 6 -type compound Y 11 Ni 60 C 6 (cI154), as well as potential consequences of this intergrowth for the phase's physical properties. Our focus begins on the structure's SCP regions, which appear as C-stuffed versions of a AuCu 3 -type YNi 3 phase that is not observed on its own in the Y-Ni system. DFT-Chemical Pressure (DFT-CP) calculations on this hypothetical YNi 3 phase reveal large negative pressures within the Ni sublattice, as it is stretched to accommodate the size requirements of the Y atoms. In the Y 11 Ni 60 C 6 structure, two structural mechanisms for addressing these CP issues appear: the incorporation of interstitial C atoms, and the presence of interfaces with CaCu 5 -type domains. The relative roles of these two mechanisms are investigated with the CP analysis on a hypothetical YNi 3 C x series of C-stuffed AuCu 3 -type phases, the Y-Ni sublattice of Y 11 Ni 60 C 6 , and finally the full Y 11 Ni 60 C 6 structure. Through these calculations, the C atoms appear to play the roles of relieving positive Y CPs and supporting relaxation at the AuCu 3 -type/CaCu 5 -type interfaces, where the cancellation occurs between opposite CPs experienced by the Y atoms in the two parent structures (following the epitaxial stabilization mechanism). The CP analysis of Y 11 Ni 60 C 6 also highlights a sublattice of Y and Ni atoms with large negative CPs (and thus the potential for soft vibrational modes), illustrating how frustrated structures could lead to the full realization of the phonon glass-electron crystal concept.

Bit Grooming: Statistically accurate precision-preserving quantization with compression, evaluated in the netCDF operators (NCO, v4.4.8+)

DOE PAGES

Zender, Charles S.

2016-09-19

Geoscientific models and measurements generate false precision (scientifically meaningless data bits) that wastes storage space. False precision can mislead (by implying noise is signal) and be scientifically pointless, especially for measurements. By contrast, lossy compression can be both economical (save space) and heuristic (clarify data limitations) without compromising the scientific integrity of data. Data quantization can thus be appropriate regardless of whether space limitations are a concern. We introduce, implement, and characterize a new lossy compression scheme suitable for IEEE floating-point data. Our new Bit Grooming algorithm alternately shaves (to zero) and sets (to one) the least significant bits ofmore » consecutive values to preserve a desired precision. This is a symmetric, two-sided variant of an algorithm sometimes called Bit Shaving that quantizes values solely by zeroing bits. Our variation eliminates the artificial low bias produced by always zeroing bits, and makes Bit Grooming more suitable for arrays and multi-dimensional fields whose mean statistics are important. Bit Grooming relies on standard lossless compression to achieve the actual reduction in storage space, so we tested Bit Grooming by applying the DEFLATE compression algorithm to bit-groomed and full-precision climate data stored in netCDF3, netCDF4, HDF4, and HDF5 formats. Bit Grooming reduces the storage space required by initially uncompressed and compressed climate data by 25–80 and 5–65 %, respectively, for single-precision values (the most common case for climate data) quantized to retain 1–5 decimal digits of precision. The potential reduction is greater for double-precision datasets. When used aggressively (i.e., preserving only 1–2 digits), Bit Grooming produces storage reductions comparable to other quantization techniques such as Linear Packing. Unlike Linear Packing, whose guaranteed precision rapidly degrades within the relatively narrow dynamic range of values that it can compress, Bit Grooming guarantees the specified precision throughout the full floating-point range. Data quantization by Bit Grooming is irreversible (i.e., lossy) yet transparent, meaning that no extra processing is required by data users/readers. Hence Bit Grooming can easily reduce data storage volume without sacrificing scientific precision or imposing extra burdens on users.« less

A Low-Cost Part-Task Flight Training System: An Application of a Head Mounted Display

DTIC Science & Technology

1990-12-01

architecture. The task at hand was to develop a software emulation libary that would emulate the function calls used within the Flight and Dog programs. This...represented in two hexadecimal digits for each color. The format of the packed long integer looks like aaggbbrr with each color value representing a...Western Digital ethernet card as the cheapest compatible card available. Good fortune arrived, as I was calling to order the card, I saw an unused card

8-Hydr­oxy-5,6,7-trimeth­oxy-2-phenyl-4H-chromen-4-one

PubMed Central

Theodoro, Jahyr E.; Santos, Djalma; Pérez, Hiram; da Silva, Maria Fátima das Graças Fernandes; Ellena, J.

2008-01-01

In the title compound, C18H16O6, the benzopyran group is essentially planar, with the O atoms of the substituent groups lying close to its mean plane. The mol­ecular conformation is governed by intra­molecular inter­actions. The crystal packing is mainly determined by one classical inter­molecular hydrogen bond which gives rise to the formation of an infinite chain along the a axis. PMID:21202382

Assembling Ordered Nanorod Superstructures and Their Application as Microcavity Lasers

NASA Astrophysics Data System (ADS)

Liu, Pai; Singh, Shalini; Guo, Yina; Wang, Jian-Jun; Xu, Hongxing; Silien, Christophe; Liu, Ning; Ryan, Kevin M.

2017-03-01

Herein we report the formation of multi-layered arrays of vertically aligned and close packed semiconductor nanorods in perfect registry at a substrate using electric field assisted assembly. The collective properties of these CdSexS1-x nanorod emitters are harnessed by demonstrating a relatively low amplified spontaneous emission (ASE) threshold and a high net optical gain at medium pump intensity. The importance of order in the system is highlighted where a lower ASE threshold is observed compared to disordered samples.

Divorced Eutectic Solidification of Mg-Al Alloys

NASA Astrophysics Data System (ADS)

Monas, Alexander; Shchyglo, Oleg; Kim, Se-Jong; Yim, Chang Dong; Höche, Daniel; Steinbach, Ingo

2015-08-01

We present simulations of the nucleation and equiaxed dendritic growth of the primary hexagonal close-packed -Mg phase followed by the nucleation of the -phase in interdendritic regions. A zoomed-in region of a melt channel under eutectic conditions is investigated and compared with experiments. The presented simulations allow prediction of the final properties of an alloy based on process parameters. The obtained results give insight into the solidification processes governing the microstructure formation of Mg-Al alloys, allowing their targeted design for different applications.

Comparison of the biological NH3 removal characteristics among four inorganic packing materials.

PubMed

Hirai, M; Kamamoto, M; Yani, M; Shoda, M

2001-01-01

Four inorganic packing materials were evaluated in terms of their availability as a packing material of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological NH3 removal characteristics and some physical properties. Porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calculated soil (D) were used. The superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of NH3 per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately = C > B > or = D. Packing materials A and C with high porosity, maximum water content, and suitable mean pore diameter showed excellent removal capacity.

Quasistatic packings of droplets in flat microfluidic channels

NASA Astrophysics Data System (ADS)

Kadivar, Erfan

2016-02-01

As observed in recent experiments, monodisperse droplets self-assemble spontaneously in different ordered packings. In this work, we present a numerical study of the droplet packings in the flat rectangular microfluidic channels. Employing the boundary element method, we numerically solve the Stokes equation in two-dimension and investigate the appearance of droplet packing and transition between one and two-row packings of monodisperse emulsion droplets. By calculating packing force applied on the droplet interface, we investigate the effect of flow rate, droplet size, and surface tension on the packing configurations of droplets and transition between different topological packings.

Scandinavian consumer preference for beef steaks packed with or without oxygen.

PubMed

Aaslyng, M D; Tørngren, M A; Madsen, N T

2010-07-01

Beef steaks retail-packed with (80% O(2), 20% CO(2)) or without oxygen (either skin-packed or gas-packed (69.6% N(2), 30% CO(2), 0.04% CO or 70% N(2), 30% CO(2))) were compared by consumers in Denmark (n=382), Norway (n=316) and Sweden (n=374). Two pairs of two steaks - one steak packed in a high oxygen atmosphere and one packed without oxygen - were given to the consumers. They were instructed to prepare the steaks at home on two consecutive days, and two persons had to taste each steak. In Denmark, the oxygen-free packing was either gas packing with CO (69.6% N(2), 30% CO(2), 0.04% CO) or without CO (70% N(2), 30% CO(2)), in Norway it was either gas packing with CO (69.6% N(2), 30% CO(2), 0.04% CO) or skin packing, and in Sweden it was either skin packing or gas packing without CO (70% N(2), 30% CO(2)). The meat represented animals that were between 17 and 80 months old (Denmark) and young bulls (Norway and Sweden). Consumers in all three countries clearly preferred steaks packed without oxygen, in terms of overall liking, willingness to pay and their preferred choice of one steak. Furthermore, they preferred the oxygen-free steaks in terms of both overall liking and liking of tenderness, juiciness and flavour. In Sweden, many consumers would pay more than usual for the skin-packed steak, and it was more often chosen as the preferred steak out of the four compared with gas-packed without oxygen. No difference was seen between the two oxygen-free packing methods in Denmark and Norway. Copyright 2010 Elsevier Ltd. All rights reserved.

The silent salesman: an observational study of personal tobacco pack display at outdoor café strips in Australia.

PubMed

Wakefield, Melanie A; Zacher, Meghan; Bayly, Megan; Brennan, Emily; Dono, Joanne; Miller, Caroline; Durkin, Sarah J; Scollo, Michelle M

2014-07-01

We sought to determine the relative frequency and nature of personal display of cigarette packs by smokers in two Australian cities where 30% front-of-pack and 90% back-of-pack health warnings have been used since 2006 and comprehensive tobacco marketing restrictions apply. An observational study counted patrons, active smokers and tobacco packs at cafés, restaurants and bars with outdoor seating. Pack orientation and use of cigarette cases were also noted. Overall, 18954 patrons, 1576 active smokers and 2153 packs were observed, meaning that one out of every 12.0 patrons was actively smoking, and one of every 8.8 patrons displayed a pack. Packs were more frequently observed in lower socio-economic neighbourhoods, reflecting the higher prevalence of smoking in those regions. Packs were displayed less often in venues where children were present, suggesting a greater tendency not to smoke around children. Most packs (81.4%) were oriented face-up, permitting prominent brand display. Only 1.5% of observed packs were cigarette cases, and 4.2% of packs were concealed by another item, such as a phone or wallet. Tobacco packs are frequently seen on table-tops in café strips, providing many opportunities for other patrons and passers-by to be incidentally exposed to cigarette brand names and imagery. Use of cigarette cases is rare, suggesting that smokers eventually habituate to pictorial warnings on branded packs and/or find repeated decanting of each newly purchased branded pack into a case to be inconvenient. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Pushing the glass transition towards random close packing using self-propelled hard spheres

NASA Astrophysics Data System (ADS)

Ni, Ran; Stuart, Martien A. Cohen; Dijkstra, Marjolein

2013-10-01

Although the concept of random close packing with an almost universal packing fraction of approximately 0.64 for hard spheres was introduced more than half a century ago, there are still ongoing debates. The main difficulty in searching the densest packing is that states with packing fractions beyond the glass transition at approximately 0.58 are inherently non-equilibrium systems, where the dynamics slows down with a structural relaxation time diverging with density; hence, the random close packing is inaccessible. Here we perform simulations of self-propelled hard spheres, and we find that with increasing activity the relaxation dynamics can be sped up by orders of magnitude. The glass transition shifts to higher packing fractions upon increasing the activity, allowing the study of sphere packings with fluid-like dynamics at packing fractions close to RCP. Our study opens new possibilities of investigating dense packings and the glass transition in systems of hard particles.

A study on parameter variation effects on battery packs for electric vehicles

NASA Astrophysics Data System (ADS)

Zhou, Long; Zheng, Yuejiu; Ouyang, Minggao; Lu, Languang

2017-10-01

As one single cell cannot meet power and driving range requirement in an electric vehicle, the battery packs with hundreds of single cells connected in parallel and series should be constructed. The most significant difference between a single cell and a battery pack is cell variation. Not only does cell variation affect pack energy density and power density, but also it causes early degradation of battery and potential safety issues. The cell variation effects on battery packs are studied, which are of great significant to battery pack screening and management scheme. In this study, the description for the consistency characteristics of battery packs was first proposed and a pack model with 96 cells connected in series was established. A set of parameters are introduced to study the cell variation and their impacts on battery packs are analyzed through the battery pack capacity loss simulation and experiments. Meanwhile, the capacity loss composition of the battery pack is obtained and verified by the temperature variation experiment. The results from this research can demonstrate that the temperature, self-discharge rate and coulombic efficiency are the major affecting parameters of cell variation and indicate the dissipative cell equalization is sufficient for the battery pack.

Knowledge and Innovation: A Comparative Study of the USA, the UK and Japan. Routledge Studies in Innovation, Organizations and Technology

ERIC Educational Resources Information Center

Brown, Helen

2012-01-01

This new book presents case studies from the US, the UK and Japan. Packed full of vignettes from cases studies and subscribing to a socio-cultural approach rather than the often tacit assumption that knowledge and "technology transfer" is a logistical problem, this excellent volume illuminates the often misunderstood process of knowledge…

Evaluation of rapid readout biological indicators for 132 degrees C gravity and 132 degrees C vacuum-assisted steam sterilization cycles using a new automated fluorescent reader.

PubMed

Alfa, Michelle J; Olson, Nancy; DeGagne, Pat; Jackson, Michele

2002-07-01

The primary objective of this study was to evaluate fluorescent readout results of Attest 1291 Biological Indicators (BIs) (3M Health Care, St. Paul, MN) and Attest 1296 BI test packs (containing Attest 1292 BIs) using full and fractional cycles compared with the growth data when prolonged incubation (7 days) was included. Gravity displacement and vacuum-assisted steam sterilization cycles were evaluated. A secondary objective of this study was to evaluate the new automated rapid fluorescent reader (Attest 290 Auto Reader). The rapid readout BIs for gravity displacement and vacuum-assisted steam autoclave cycles at 132 degrees C were processed using full (4 minutes) and four fractional cycles that provided 30% to 80% positive results for growth after 24 hours of incubation (48 hours of incubation for Attest 1292 BIs from the Attest 1296 test packs). Sixty of each type of BI were tested for each cycle (300 of each BI type in total). For all full steam sterilization cycles, results of the rapid fluorescent readout and the 24-hour, 48-hour, and 7-day growth tests were negative for all Attest 1291 and 1292 BIs tested. For all fractional cycles, the 24- and 48-hour growth results for the Attest 1291 and 1292 BIs, respectively, were the same as the 7-day growth results. The fractional cycle data indicated that fluorescent rapid readout was a more sensitive indicator than growth. There were rare (0.9%) false-negative results for BIs under fractional cycle conditions and these all correlated with short fractional cycle exposure times. The fluorescent rapid readout results of the 1291 BIs and 1296 BI test packs reliably predict both 24- and 48-hour and 7-day growth. These data support the value of rapid readout BIs for sterilizer monitoring for both the vacuum-assisted and the gravity displacement steam sterilization cycles. The new automated reader requires less manipulation of the BI and makes monitoring user friendly and less prone to user errors.

Young adult smokers' perceptions of illicit tobacco and the possible impact of plain packaging on purchase behaviour.

PubMed

Moodie, Crawford; Hastings, Gerard; Joossens, Luk

2012-04-01

Plain (unbranded) packaging for cigarettes is at the top of the tobacco control agenda in both Australia and Europe. The evidence suggests that it will benefit public health by decreasing the appeal of tobacco products and increasing the power of the health warning. The tobacco industry instead argues that plain packaging would make it easier to counterfeit cigarettes, which would both confuse consumers and reduce price; thereby increasing consumption. Using focus group research we examined young adult smokers (N = 54) perceptions of, and ability to recognize, illicit tobacco and the possible impact of plain packaging on illicit tobacco purchasing behaviour. We found that the pack has no impact on the decision to buy illicit tobacco. Smokers were easily able to identify counterfeit cigarettes, not least by the pack, and buy it knowingly and in the full expectation that it will be inferior in quality. Illicit tobacco purchase, including that for counterfeit tobacco, was instead driven by availability and price. Given the extremely low manufacturing cost, per pack, of certain types of illicit cigarettes, it is difficult to envisage how plain packaging would alter the price of illicit tobacco in any meaningful way. The findings therefore suggest that a move to plain packaging would have no impact on young adult smokers' purchase behaviour.

Adsorption and Dissociation of Molecular Oxygen on the (0001) Surface of Double Hexagonal Close Packed Americium

NASA Astrophysics Data System (ADS)

Dholabhai, Pratik; Atta-Fynn, Raymond; Ray, Asok

2008-03-01

Oxygen molecule adsorption on (0001) surface of double hexagonal packed americium has been studied in detail within the framework of density functional theory using a full-potential all-electron linearized augmented plane wave plus local orbitals method. The most stable configuration corresponded to molecular dissociation with the oxygen atoms occupying neighboring three-fold hollow h3 sites. Chemisorption energies and adsorption geometries for the adsorbed species, and change in work functions, magnetic moments, partial charges inside muffin-tins, difference charge density distributions and density of states for the bare Am slab and the Am slab after adsorption of the oxygen molecule will be discussed. The effects of chemisorption on Am 5f electron localization-delocalization in the vicinity of the Fermi level and the reaction barrier calculation for the dissociation of oxygen molecule to the most stable h3 sites will be discussed.

A Density Functional Study of Atomic Hydrogen and Oxygen Chemisorptions on the (0001) Surface of Double Hexagonal Close Packed Americium

NASA Astrophysics Data System (ADS)

Dholabhai, Pratik; Atta-Fynn, Raymond; Ray, Asok

2008-03-01

Ab initio total energy calculations within the framework of density functional theory have been performed for atomic hydrogen and oxygen chemisorptions on the (0001) surface of double hexagonal packed americium using a full-potential all-electron linearized augmented plane wave plus local orbitals (FLAPW+lo) method. The three-fold hollow hcp site was found to be the most stable site for H adsorption, while the two-fold bridge adsorption site was found to be the most stable site for O adsorption. Chemisorption energies and adsorption geometries for different adsorption sites will be discussed. The change in work functions, magnetic moments, partial charges inside muffin-tins, difference charge density distributions and density of states for the bare Am slab and the Am slab after adsorption of the adatom will be discussed. The implications of chemisorption on Am 5f electron localization-delocalization will also be discussed.

Bone bonding in bioactive glass ceramics combined with a new synthesized agent TAK-778.

PubMed

Kato, H; Neo, M; Tamura, J; Nakamura, T

2001-11-01

We studied the stimulatory effects of TAK-778, a new synthetic 3-benzothiepin derivative that promotes osteoblast differentiation, in the bonding of bone to bioactive glass ceramic implants in rabbit tibiae. Smooth-surfaced, rectangular plates (15 x 10 x 2 mm) made of apatite-wollastonite-containing glass ceramic were implanted bilaterally into the proximal metaphyses of rabbit tibiae. Sustained-release microcapsules containing TAK-778 were packed into the medullary cavity in one limb and untreated microcapsules were packed into the contralateral limb to serve as a paired control. At 4, 8, and 16 weeks after implantation, bonding at the bone/implant interfaces was evaluated using a detaching test and histological examination of undecalcified specimens. The tensile failure load increased during weeks 4 to 16 in both groups; the tensile failure load in the TAK-778-treated group was significantly greater than that in the control group at each interval after implantation. Histologically, the TAK-778-treated specimens showed greater active new bone formation mainly in the medullary cavity and more extensive bonding between the implant and bone than the untreated specimens. The results of this study suggest that adding the bone formation-promoting TAK-778 to bioactive glass ceramic implants may significantly accelerate bone apposition to the implants and improve the bonding process at the interface. This would help to establish earlier and stronger bonding of orthopedic ceramic implants to the surrounding bone tissue. Copyright 2001 John Wiley & Sons, Inc.

Textural and mineralogical study of sandstones from the onshore Gulf of Alaska Tertiary Province, southern Alaska

USGS Publications Warehouse

Winkler, Gary R.; McLean, Hugh; Plafker, George

1976-01-01

Petrographic examination of 74 outcrop samples of Paleocene through Pliocene age from the onshore Gulf of Alaska Tertiary Province indicates that sandstones of the province characteristically are texturally immature and mineralogically unstable. Diagenetic alteration of framework grains throughout the stratigraphic sequence has produced widespread zeolite cement or phyllosilicate grain coatings and pseudomatrix. Multiple deformation and deep burial of the older Tertiary sequence--the Orca Group, the shale of Haydon Peak, and the Kulthieth and Tokun Formations--caused extensive alteration and grain interpenetration, resulting in low porosity values. Less intense deformation and intermediate depth of burial of the younger Tertiary sequence--the Katalla, Poul Creek, Redwood, and Yakataga Formations--has resulted in a greater range in textural properties. Most sandstone samples in the younger Tertiary sequence are poorly sorted, tightly packed, and have strongly appressed framework grains, but some are less tightly packed and contain less matrix. Soft and mineralogically unstable framework grains have undergone considerable alteration, reducing pore space even in the youngest rocks. Measurements of porosity, permeability, grain density, and sonic velocity of outcrop samples of the younger Tertiary sequence indicate a modest up-section improvement in sandstone reservoir characteristics. Nonetheless porosity and permeability values typically are below 16 percent and 15 millidarcies respectively and grain densities are consistently high, about 2.7 gm/cc. Low permeability and porosity values, and high grain densities and sonic velocities appear to be typical of most outcrop areas throughout the onshore Gulf of Alaska Tertiary Province.

Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method.

PubMed

Ouertani, Rachid; Hamdi, Abderrahmen; Amri, Chohdi; Khalifa, Marouan; Ezzaouia, Hatem

2014-01-01

In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films.

Formation of silicon nanowire packed films from metallurgical-grade silicon powder using a two-step metal-assisted chemical etching method

PubMed Central

2014-01-01

In this work, we use a two-step metal-assisted chemical etching method to produce films of silicon nanowires shaped in micrograins from metallurgical-grade polycrystalline silicon powder. The first step is an electroless plating process where the powder was dipped for few minutes in an aqueous solution of silver nitrite and hydrofluoric acid to permit Ag plating of the Si micrograins. During the second step, corresponding to silicon dissolution, we add a small quantity of hydrogen peroxide to the plating solution and we leave the samples to be etched for three various duration (30, 60, and 90 min). We try elucidating the mechanisms leading to the formation of silver clusters and silicon nanowires obtained at the end of the silver plating step and the silver-assisted silicon dissolution step, respectively. Scanning electron microscopy (SEM) micrographs revealed that the processed Si micrograins were covered with densely packed films of self-organized silicon nanowires. Some of these nanowires stand vertically, and some others tilt to the silicon micrograin facets. The thickness of the nanowire films increases from 0.2 to 10 μm with increasing etching time. Based on SEM characterizations, laser scattering estimations, X-ray diffraction (XRD) patterns, and Raman spectroscopy, we present a correlative study dealing with the effect of the silver-assisted etching process on the morphological and structural properties of the processed silicon nanowire films. PMID:25349554

The effect of cigarette branding and plain packaging on female youth in the United Kingdom.

PubMed

Hammond, David; Daniel, Samantha; White, Christine M

2013-02-01

Cigarette packaging is the most prominent form of tobacco marketing remaining in countries such as the United Kingdom. The current study examined perceptions of cigarette packaging among female youth and the potential impact of "plain" cigarette packaging regulations. A national sample of 947 16- to 19-year-old female subjects in the United Kingdom completed an online survey. Participants were randomized to view 10 cigarette packs designed according to one of four experimental conditions: fully branded female packs, the same packs without descriptor words, the same packs without brand imagery or descriptors ("plain" packs), and branded non-female brands. Participants rated packs on measures of appeal and health risk, positive smoker image, and completed a behavioral pack selection task. Plain packs were rated as the least appealing and worse tasting compared with all other conditions. Plain packs were also associated with fewer false beliefs about health risks compared with branded packs. Removing brand descriptors from packs significantly reduced measures of appeal and taste, particularly for brands with flavor descriptors, such as cherry and vanilla. Plain packs were significantly less likely to be associated with positive images, such as glamour, sophistication, and slimness. Most importantly, respondents were significantly less likely to accept a pack of cigarettes when offered only plain versus branded packs (p = .026). Marketing in the form of pack branding remains a potent tool for increasing the appeal of tobacco products to young women. The findings provide empirical support for plain cigarette packaging regulations in Australia to be implemented in 2012. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Kinetics of pack aluminization of nickel

NASA Technical Reports Server (NTRS)

Seigle, L. L.; Gupta, B. K.; Shankar, R.; Sarkhel, A. K.

1978-01-01

The kinetics of pack aluminization of unalloyed nickel in packs of varying aluminum activity with various halide activators were studied. Surface compositions of the coatings as functions of time, temperature, and pack composition were obtained in order to establish the boundary conditions for diffusion in the system. The structure of the packs was also examined in order to clarify the mechanism of aluminum transport. The results indicate that the kinetics of pack aluminization are controlled jointly by gas diffusion in the pack and solid diffusion in the coating. Levine and Caves' model for gas diffusion was combined with calculations of rates of diffusion in the solid to formulate a more complete theory for the kinetics of pack aluminization.

Comparison of the biological H2S removal characteristics among four inorganic packing materials.

PubMed

Hirai, M; Kamamoto, M; Yani, M; Shoda, M

2001-01-01

Four inorganic packing materials were evaluated in terms of their availability as packing materials of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological H2S removal characteristics and some physical properties. Among porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calcinated soil (D), the superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of H2S per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately equal to C > D approximately equal to B, which is correlated with the maximum water content, porosity, and mean pore diameter.

Densest local sphere-packing diversity. II. Application to three dimensions

NASA Astrophysics Data System (ADS)

Hopkins, Adam B.; Stillinger, Frank H.; Torquato, Salvatore

2011-01-01

The densest local packings of N three-dimensional identical nonoverlapping spheres within a radius Rmin(N) of a fixed central sphere of the same size are obtained for selected values of N up to N=1054. In the predecessor to this paper [A. B. Hopkins, F. H. Stillinger, and S. Torquato, Phys. Rev. EPLEEE81063-651X10.1103/PhysRevE.81.041305 81, 041305 (2010)], we described our method for finding the putative densest packings of N spheres in d-dimensional Euclidean space Rd and presented those packings in R2 for values of N up to N=348. Here we analyze the properties and characteristics of the densest local packings in R3 and employ knowledge of the Rmin(N), using methods applicable in any d, to construct both a realizability condition for pair correlation functions of sphere packings and an upper bound on the maximal density of infinite sphere packings. In R3, we find wide variability in the densest local packings, including a multitude of packing symmetries such as perfect tetrahedral and imperfect icosahedral symmetry. We compare the densest local packings of N spheres near a central sphere to minimal-energy configurations of N+1 points interacting with short-range repulsive and long-range attractive pair potentials, e.g., 12-6 Lennard-Jones, and find that they are in general completely different, a result that has possible implications for nucleation theory. We also compare the densest local packings to finite subsets of stacking variants of the densest infinite packings in R3 (the Barlow packings) and find that the densest local packings are almost always most similar as measured by a similarity metric, to the subsets of Barlow packings with the smallest number of coordination shells measured about a single central sphere, e.g., a subset of the fcc Barlow packing. Additionally, we observe that the densest local packings are dominated by the dense arrangement of spheres with centers at distance Rmin(N). In particular, we find two “maracas” packings at N=77 and N=93, each consisting of a few unjammed spheres free to rattle within a “husk” composed of the maximal number of spheres that can be packed with centers at respective Rmin(N).

Ephemeroptera, Plecoptera and Trichoptera (Insecta) Abundance, Diversity and Role in Leaf Litter Breakdown in Tropical Headwater River

PubMed Central

Ab Hamid, Suhaila; Md Rawi, Che Salmah

2017-01-01

Leaf litter decomposition in a tropical stream was examined in two types of leaf packs; single species leaf packs of Pometia pinnata and two species leaf packs of equal combination of Pometia pinnata and Dolichandrone spathacea leaves. Both leaf packs were immersed in a river and weekly examined for remains of decomposed leaves and presence of EPT. In the control leaf packs, leaves in the two species leaf packs treatments decomposed within 35 days, faster than in single species leaf packs which decomposed after 42 days. In the presence of EPT, the leaf breakdown took 28 days in two species and 35 days for single species leaf packs. Higher abundance of EPT was observed in single species leaf packs but its diversity was higher in two species leaf packs. Litter breakdown in the stream was faster in the presence of EPT and softer leaves of D. spathacea with higher nitrogen content underwent faster decomposition and sustained higher numbers of EPT. PMID:28890763

Ephemeroptera, Plecoptera and Trichoptera (Insecta) Abundance, Diversity and Role in Leaf Litter Breakdown in Tropical Headwater River.

PubMed

Ab Hamid, Suhaila; Md Rawi, Che Salmah

2017-07-01

Leaf litter decomposition in a tropical stream was examined in two types of leaf packs; single species leaf packs of Pometia pinnata and two species leaf packs of equal combination of Pometia pinnata and Dolichandrone spathacea leaves. Both leaf packs were immersed in a river and weekly examined for remains of decomposed leaves and presence of EPT. In the control leaf packs, leaves in the two species leaf packs treatments decomposed within 35 days, faster than in single species leaf packs which decomposed after 42 days. In the presence of EPT, the leaf breakdown took 28 days in two species and 35 days for single species leaf packs. Higher abundance of EPT was observed in single species leaf packs but its diversity was higher in two species leaf packs. Litter breakdown in the stream was faster in the presence of EPT and softer leaves of D. spathacea with higher nitrogen content underwent faster decomposition and sustained higher numbers of EPT.

Centrifugal sedimentation for selectively packing channels with silica microbeads in three-dimensional micro/nanofluidic devices.

PubMed

Gong, Maojun; Bohn, Paul W; Sweedler, Jonathan V

2009-03-01

Incorporation of nanofluidic elements into microfluidic channels is one approach for adding filtration and partition functionality to planar microfluidic devices, as well as providing enhanced biomolecular separations. Here we introduce a strategy to pack microfluidic channels with silica nanoparticles and microbeads, thereby indirectly producing functional nanostructures; the method allows selected channels to be packed, here demonstrated so that a separation channel is packed while keeping an injection channel unpacked. A nanocapillary array membrane is integrated between two patterned microfluidic channels that cross each other in vertically separated layers. The membrane serves both as a frit for bead packing and as a fluid communication conduit between microfluidic channels. Centrifugal force-assisted sedimentation is then used to selectively pack the microfluidic channels using an aqueous silica bead suspension loaded into the appropriate inlet reservoirs. This packing approach may be used to simultaneously pack multiple channels with silica microbeads having different sizes and surface properties. The chip design and packing method introduced here are suitable for packing silica particles in sizes ranging from nanometers to micrometers and allow rapid (approximately 10 min) packing with high quality. The liquid/analyte transport characteristics of these packed micro/nanofluidic devices have potential utility in a wide range of applications, including electroosmotic pumping, liquid chromatographic separations, and electrochromatography.

Adhesive loose packings of small dry particles.

PubMed

Liu, Wenwei; Li, Shuiqing; Baule, Adrian; Makse, Hernán A

2015-08-28

We explore adhesive loose packings of small dry spherical particles of micrometer size using 3D discrete-element simulations with adhesive contact mechanics and statistical ensemble theory. A dimensionless adhesion parameter (Ad) successfully combines the effects of particle velocities, sizes and the work of adhesion, identifying a universal regime of adhesive packings for Ad > 1. The structural properties of the packings in this regime are well described by an ensemble approach based on a coarse-grained volume function that includes the correlation between bulk and contact spheres. Our theoretical and numerical results predict: (i) an equation of state for adhesive loose packings that appear as a continuation from the frictionless random close packing (RCP) point in the jamming phase diagram and (ii) the existence of an asymptotic adhesive loose packing point at a coordination number Z = 2 and a packing fraction ϕ = 1/2(3). Our results highlight that adhesion leads to a universal packing regime at packing fractions much smaller than the random loose packing (RLP), which can be described within a statistical mechanical framework. We present a general phase diagram of jammed matter comprising frictionless, frictional, adhesive as well as non-spherical particles, providing a classification of packings in terms of their continuation from the spherical frictionless RCP.

Structural design of graphene for use in electrochemical energy storage devices.

PubMed

Chen, Kunfeng; Song, Shuyan; Liu, Fei; Xue, Dongfeng

2015-10-07

There are many practical challenges in the use of graphene materials as active components in electrochemical energy storage devices. Graphene has a much lower capacitance than the theoretical capacitance of 550 F g(-1) for supercapacitors and 744 mA h g(-1) for lithium ion batteries. The macroporous nature of graphene limits its volumetric energy density and the low packing density of graphene-based electrodes prevents its use in commercial applications. Increases in the capacity, energy density and power density of electroactive graphene materials are strongly dependent on their microstructural properties, such as the number of defects, stacking, the use of composite materials, conductivity, the specific surface area and the packing density. The structural design of graphene electrode materials is achieved via six main strategies: the design of non-stacking and three-dimensional graphene; the synthesis of highly packed graphene; the production of graphene with a high specific surface area and high conductivity; the control of defects; functionalization with O, N, B or P heteroatoms; and the formation of graphene composites. These methodologies of structural design are needed for fast electrical charge storage/transfer and the transport of electrolyte ions (Li(+), H(+), K(+), Na(+)) in graphene electrodes. We critically review state-of-the-art progress in the optimization of the electrochemical performance of graphene-based electrode materials. The structure of graphene needs to be designed to develop novel electrochemical energy storage devices that approach the theoretical charge limit of graphene and to deliver electrical energy rapidly and efficiently.

Improving the packing density of calcium phosphate coating on a magnesium alloy for enhanced degradation resistance.

PubMed

Kannan, M Bobby

2013-05-01

In this study, an attempt was made to improve the packing density of calcium phosphate (CaP) coating on a magnesium alloy by tailoring the coating solution for enhanced degradation resistance of the alloy for implant applications. An organic solvent, ethanol, was added to the coating solution to decrease the conductivity of the coating solution so that hydrogen bubble formation/bursting reduces during the CaP coating process. Experimental results confirmed that ethanol addition to the coating solution reduces the conductivity of the solution and also decreases the hydrogen evolution/bubble bursting. In vitro electrochemical experiments, that is, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization showed that CaP coating produced in 30% (v/v) ethanol containing coating solution (3E) exhibits significantly higher degradation resistance (i.e., ~50% higher polarization resistance and ~60% lower corrosion current) than the aqueous solution coating. Scanning electron microscope (SEM) analysis of the coatings revealed that the packing of 3E coating was denser than that of aqueous coating, which can be attributed to the lower hydrogen evolution in the former than in the latter. Further increase in the ethanol content in the coating solution was not beneficial; in fact, the coating produced in 70% (v/v) ethanol containing solution (7E) showed degradation resistance much inferior to that of the aqueous coating, which is due to low thickness of 7E coating. Copyright © 2012 Wiley Periodicals, Inc.

Production enhancement through aggressive flowback procedures in the Codell formation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anderson, A.J.; Ashton, P.J.N.; Lang, J.

1996-12-31

Proppant flowback following fracture stimulation treatments continues to be a major concern in many wells around the world. The current trend towards more tip screen out (TSO) and reverse screenout designs has increased the need for better control of proppant flowback under increasingly severe drag force conditions. Recent studies in the Codell formation have indicated a correlation between load water and polymer recovery on fracture cleanup and subsequent gas production. This paper describes a subsequent twenty-five well study of the specific effects of combining forced closure/reverse gravel packs along with varying flowback rates and choke schedules on load water recoverymore » and normalized gas and condensate production. One of the key issues addressed is the use of aggressive flowback schedules while maintaining proppant flowback control.« less

An aqueous electrolyte, sodium ion functional, large format energy storage device for stationary applications

NASA Astrophysics Data System (ADS)

Whitacre, J. F.; Wiley, T.; Shanbhag, S.; Wenzhuo, Y.; Mohamed, A.; Chun, S. E.; Weber, E.; Blackwood, D.; Lynch-Bell, E.; Gulakowski, J.; Smith, C.; Humphreys, D.

2012-09-01

An approach to making large format economical energy storage devices based on a sodium-interactive set of electrodes in a neutral pH aqueous electrolyte is described. The economics of materials and manufacturing are examined, followed by a description of an asymmetric/hybrid device that has λ-MnO2 positive electrode material and low cost activated carbon as the negative electrode material. Data presented include materials characterization of the active materials, cyclic voltammetry, galvanostatic charge/discharge cycling, and application-specific performance of an 80 V, 2.4 kW h pack. The results indicate that this set of electrochemical couples is stable, low cost, requires minimal battery management control electronics, and therefore has potential for use in stationary applications where device energy density is not a concern.

Effect of Co on Discontinuous Precipitation Transformation with TCP Phase in Ni-based Alloy Containing Re

NASA Astrophysics Data System (ADS)

Shi, Qianying; An, Ning; Huo, Jiajie; Zheng, Yunrong; Feng, Qiang

2017-05-01

The effect of Co on discontinuous precipitation (DP) transformation involving the formation of topologically close-packed (TCP) phase was investigated in three Ni-Cr-Re model alloys containing different levels of Co. One typical TCP phase, σ, was generated within DP cellular colonies along the migrating grain boundaries in experimental alloys during aging treatment. As a result of the increased solubility of Re in the γ matrix and enlarged interlamellar spacing of σ precipitates inside of growing DP colonies, Co addition suppressed the formation of σ phase and associated DP colonies. This study suggests that Co could potentially serve as a microstructural stabilizer in Re-containing Ni-base superalloys, which provides an alternative method for the composition optimization of superalloys.

Premicellar and micelle formation behavior of dye surfactant ion pairs in aqueous solutions: deprotonation of dye in ion pair micelles.

PubMed

Gohain, Biren; Dutta, Robin K

2008-07-15

The premicellar and micelle formation behavior of dye surfactant ion pairs in aqueous solutions monitored by surface tension and spectroscopic measurements has been described. The measurements have been made for three anionic sulfonephthalein dyes and cationic surfactants of different chain lengths, head groups, and counterions. The observations have been attributed to the formation of closely packed dye surfactant ion pairs which is similar to nonionic surfactants in very dilute concentrations of the surfactant. These ion pairs dominate in the monolayer at the air-water interface of the aqueous dye surfactant solutions below the CMC of the pure surfactant. It has been shown that the dye in the ion pair deprotonates on micelle formation by the ion pair surfactants at near CMC but submicellar surfactant concentrations. The results of an equilibrium study at varying pH agree with the model of deprotonated 1:1 dye-surfactant ion pair formation in the near CMC submicellar solutions. At concentrations above the CMC of the cationic surfactant the dye is solubilized in normal micelles and the monolayer at the air-water interface consists of the cationic surfactant alone even in the presence of the dyes.

7 CFR 51.310 - Packing requirements.

Code of Federal Regulations, 2014 CFR

2014-01-01

... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged.... 3 2 “Fairly tight” means that apples are of the proper size for molds or cell compartments in which...

7 CFR 51.310 - Packing requirements.

Code of Federal Regulations, 2013 CFR

2013-01-01

... (INSPECTION, CERTIFICATION, AND STANDARDS) United States Standards for Grades of Apples Packing Requirements § 51.310 Packing requirements. (a) Apples tray packed or cell packed in cartons shall be arranged.... 3 2 “Fairly tight” means that apples are of the proper size for molds or cell compartments in which...

Sleeping distance in wild wolf packs

USGS Publications Warehouse

Knick, S.T.; Mech, L.D.

1980-01-01

Sleeping distances were observed among members of 13 wild wolf (Canis lupus) packs and 11 pairs in northeastern Minnesota to determine if the distances correlated with pack size and composition. The study utilized aerial radio-tracking and observation during winter. Pack size and number of adults per pack were inversely related to pack average sleeping distance and variability. No correlation between sleeping distance and microclimate was observed. Possible relationships between social bonding and our results are discussed.

Marginal rigidity and history dependence in packings of attractive athermal emulsions

NASA Astrophysics Data System (ADS)

Bargteil, Dylan; Pontani, Lea-Laetitia; Brujic, Jasna

2014-03-01

The geometry and stress through particulate packings depends on the method of preparation and the interaction potential between the particles. Previously, we discovered that creaming frictionless, athermal emulsions with a short-range depletion attraction leads to an initial increase in the packing density above random close packing, followed by a monotonic decrease in density (Jorjadze et al, PNAS, 2011). This decrease is because the attractive force stabilizes loose voids, thus reducing the average coordination number, , of the packing. In order to understand the mechanism of packing creation, we investigate whether the final density is influenced by the polydispersity or the initial volume fraction of droplets, as it is in frictional packings. Finally, we compress the attractive packings by centrifugation to probe the scaling laws of pressure versus density and and compare them with those found in repulsive packings (Jorjadze et al, PRL, 2013).

Influence of catalyst packing configuration on the discharge characteristics of dielectric barrier discharge reactors: A numerical investigation

NASA Astrophysics Data System (ADS)

Gadkari, Siddharth; Gu, Sai

2018-06-01

A two-dimensional numerical fluid model is developed for studying the influence of packing configurations on dielectric barrier discharge (DBD) characteristics. Discharge current profiles and time averaged electric field strength, electron number density, and electron temperature distributions are compared for the three DBD configurations, plain DBD with no packing, partially packed DBD, and fully packed DBD. The results show that a strong change in discharge behaviour occurs when a DBD is fully packed as compared to partial packing or no packing. While the average electric field strength and electron temperature of a fully packed DBD are higher relative to the other DBD configurations, the average electron density is substantially lower and may impede the DBD reactor performance under certain operating conditions. Possible scenarios of the synergistic effect of the combination of plasma with catalysis are also discussed.

Hemato-biochemical responses to packing in donkeys administered ascorbic acid during the harmattan season.

PubMed

Olaifa, Folashade; Ayo, Joseph Olusegun; Ambali, Suleiman Folorunsho; Rekwot, Peter Ibrahim

2015-02-01

Experiments were performed to investigate the effect of ascorbic acid (AA) in reducing hemato-biochemical changes in pack donkeys during the cold-dry (harmattan) season. Six experimental donkeys administered orally AA (200 mg/kg) and six control donkeys not administered ascorbic acid were subjected to packing. Blood samples were collected from all donkeys for hematological and biochemical analyses. In the control donkeys, packed cell volume (PCV), erythrocyte count and hemoglobin concentration (Hb) decreased significantly (P<0.05) at the end of packing. In the experimental donkeys, there was no significant difference between the pre- and post-packing values of PCV, erythrocyte count and Hb. In the control donkeys, the neutrophil and neutrophil:lymphocyte ratio increased significantly (P<0.05) post packing, but in the experimental donkeys, the pre- and post-packing values were not significantly different. The eosinophil count increased significantly (P<0.05) in experimental and control donkeys post packing. In conclusion, packing exerted significant adverse effects on the hematological parameters ameliorated by AA administration. AA may modulate neutrophilia and induce a considerable alteration of erythroid markers in donkeys subjected to packing during the harmattan season.

Hemato-biochemical responses to packing in donkeys administered ascorbic acid during the harmattan season

PubMed Central

OLAIFA, Folashade; AYO, Joseph Olusegun; AMBALI, Suleiman Folorunsho; REKWOT, Peter Ibrahim

2012-01-01

Experiments were performed to investigate the effect of ascorbic acid (AA) in reducing hemato-biochemical changes in pack donkeys during the cold-dry (harmattan) season. Six experimental donkeys administered orally AA (200 mg/kg) and six control donkeys not administered ascorbic acid were subjected to packing. Blood samples were collected from all donkeys for hematological and biochemical analyses. In the control donkeys, packed cell volume (PCV), erythrocyte count and hemoglobin concentration (Hb) decreased significantly (P<0.05) at the end of packing. In the experimental donkeys, there was no significant difference between the pre- and post-packing values of PCV, erythrocyte count and Hb. In the control donkeys, the neutrophil and neutrophil:lymphocyte ratio increased significantly (P<0.05) post packing, but in the experimental donkeys, the pre- and post-packing values were not significantly different. The eosinophil count increased significantly (P<0.05) in experimental and control donkeys post packing. In conclusion, packing exerted significant adverse effects on the hematological parameters ameliorated by AA administration. AA may modulate neutrophilia and induce a considerable alteration of erythroid markers in donkeys subjected to packing during the harmattan season. PMID:23154452

Vacuum packing: a model system for laboratory-scale silage fermentations.

PubMed

Johnson, H E; Merry, R J; Davies, D R; Kell, D B; Theodorou, M K; Griffith, G W

2005-01-01

To determine the utility of vacuum-packed polythene bags as a convenient, flexible and cost-effective alternative to fixed volume glass vessels for lab-scale silage studies. Using perennial ryegrass or red clover forage, similar fermentations (as assessed by pH measurement) occurred in glass tube and vacuum-packed silos over a 35-day period. As vacuum-packing devices allow modification of initial packing density, the effect of four different settings (initial packing densities of 0.397, 0.435, 0.492 and 0.534 g cm(-3)) on the silage fermentation over 16 days was examined. Significant differences in pH decline and lactate accumulation were observed at different vacuum settings. Gas accumulation was apparent within all bags and changes in bag volume with time was observed to vary according to initial packing density. Vacuum-packed silos do provide a realistic model system for lab-scale silage fermentations. Use of vacuum-packed silos holds potential for lab-scale evaluations of silage fermentations, allowing higher throughput of samples, more consistent packing as well as the possibility of investigating the effects of different initial packing densities and use of different wrapping materials.

A randomized trial of Rapid Rhino Riemann and Telfa nasal packs following endoscopic sinus surgery.

PubMed

Cruise, A S; Amonoo-Kuofi, K; Srouji, I; Kanagalingam, J; Georgalas, C; Patel, N N; Badia, L; Lund, V J

2006-02-01

To compare Telfa with the Rapid Rhino Riemann nasal pack for use following endoscopic sinus surgery. Prospective, randomized, double-blind, paired trial. Tertiary otolaryngology hospital. Forty-five adult patients undergoing bilateral endoscopic sinus surgery for either chronic rhinosinusitis or nasal polyps. A visual analogue scale was used to assess discomfort caused by the presence of the packs in the nose and by their removal. The amount of bleeding was noted with the packs in place and following their removal. Crusting and adhesions were assessed 2 and 6 weeks following surgery. Both packs performed well giving good haemostasis and causing little bleeding on removal. Both packs caused only mild discomfort while in the nose. On the visual analogue scale of 0-10 cm the mean visual analogue score for Rapid Rhino Riemann pack was 1.7 and for Telfa 2.0 (P = 0.371). The Rapid Rhino Riemann pack caused significantly less pain on removal compared with the Telfa pack with a mean visual analogue score of 2.0 in comparison with 3.7 for Telfa (P = 0.001). There were less adhesions with the Rapid Rhino Riemann than Telfa pack but this was not statistically significant (P = 0.102). Both Telfa and Rapid Rhino Riemann packs can be recommended as packs that control postoperative haemorrhage, do not cause bleeding on removal and cause little discomfort while in the nose. The Rapid Rhino Riemann pack has the advantage of causing significantly less pain on removal.

Volatile organic compounds emission control in industrial pollution source using plasma technology coupled with F-TiO2/γ-Al2O3.

PubMed

Zhu, Tao; Chen, Rui; Xia, Ni; Li, Xiaoyang; He, Xianxian; Zhao, Wenjuan; Carr, Tim

2015-01-01

Volatile organic compounds' (VOCs) effluents, which come from many industries, are triggering serious environmental problems. As an emerging technology, non-thermal plasma (NTP) technology is a potential technology for VOCs emission control. NTP coupled with F-TiO2/γ-Al2O3 is used for toluene removal from a gaseous influent at normal temperature and atmospheric pressure. NTP is generated by dielectric barrier discharge, and F-TiO2/γ-Al2O3 can be prepared by sol-gel method in the laboratory. In the experiment, the different packed materials were packed into the plasma reactor, including γ-Al2O3, TiO2/γ-Al2O3 and F-TiO2/γ-Al2O3. Through a series of characterization methods such as X-ray diffraction, scanning electronic microscopy and Brunner-Emmet-Teller measurements, the results show that the particle size distribution of F-TiO2 is relatively smaller than that of TiO2, and the pore distribution of F-TiO2 is more uniformly distributed than that of TiO2. The relationships among toluene removal efficiency, reactor input energy density, and the equivalent capacitances of air gap and dielectric barrier layer were investigated. The results show that the synergistic technology NTP with F-TiO2/γ-Al2O3 resulted in greater enhancement of toluene removal efficiency and energy efficiency. Especially, when packing with F-TiO2/γ-Al2O3 in NTP reactor, toluene removal efficiency reaches 99% and higher. Based on the data analysis of Fourier Transform Infrared Spectroscopy, the experimental results showed that NTP reactor packed with F-TiO2/γ-Al2O3 resulted in a better inhibition for by-products formation effectively in the gas exhaust.

An exposure study of bystanders and workers during the installation and removal of asbestos gaskets and packing.

PubMed

Mangold, Carl; Clark, Katherine; Madl, Amy; Paustenbach, Dennis

2006-02-01

From 1982 until 1991, a series of studies was performed to evaluate the airborne concentration of chrysotile asbestos associated with replacing gaskets and packing materials. These studies were conducted by the senior author in response to concerns raised by a report from the Navy in 1978 on asbestos exposures associated with gasket work. A series of studies was conducted because results of those who worked with gaskets within the Navy study did not address the background concentrations of asbestos in the work areas, which may have been significant due to the presence of asbestos insulation in the ships and shipyards. The intent of the studies performed from 1982 through 1991 was to re-create the Navy's work practices in a contaminant-free environment during an 8-hour workday (so the data could be compared with the OSHA permissible exposure limit [PEL]). Samples were collected to characterize personal and area airborne asbestos concentrations associated with the formation, removal, and storage of gaskets, as well as the scraping of flanges and the replacement of valve packing. The results indicate that the 8-hour time-weighted average (TWA) exposures of pipefitters and other tradesmen who performed these activities were below the current PEL and all previous PELs. Specifically, the highest average 8-hour TWA concentration measured for workers manipulating asbestos gaskets during this study was 0.030 f/cc (during gasket removal and flange face scraping onboard a naval ship). Likewise, the 8-hour TWA breathing zone concentrations of a worker removing and replacing asbestos valve packing did not exceed 0.016 f/cc. In most cases, the concentrations were not distinguishable from ambient levels of asbestos in the ships or the general environment. These results are not surprising given that asbestos fibers in gasket materials are encapsulated within a binder.

Atmospheric forcing of sea ice leads in the Beaufort Sea

NASA Astrophysics Data System (ADS)

Lewis, B. J.; Hutchings, J.; Mahoney, A. R.; Shapiro, L. H.

2016-12-01

Leads in sea ice play an important role in the polar marine environment where they allow heat and moisture transfer between the oceans and atmosphere and act as travel pathways for both marine mammals and ships. Examining AVHRR thermal imagery of the Beaufort Sea, collected between 1994 and 2010, sea ice leads appear in repeating patterns and locations (Eicken et al 2005). The leads, resolved by AVHRR, are at least 250m wide (Mahoney et al 2012), thus the patterns described are for lead systems that extend up to hundreds of kilometers across the Beaufort Sea. We describe how these patterns are associated with the location of weather systems relative to the coastline. Mean sea level pressure and 10m wind fields from ECMWF ERA-Interim reanalysis are used to identify if particular lead patterns can be uniquely forecast based on the location of weather systems. Ice drift data from the NSIDC's Polar Pathfinder Daily 25km EASE-Grid Sea Ice Motion Vectors indicates the role shear along leads has on the motion of ice in the Beaufort Gyre. Lead formation is driven by 4 main factors: (i) coastal features such as promontories and islands influence the origin of leads by concentrating stresses within the ice pack; (ii) direction of the wind forcing on the ice pack determines the type of fracture, (iii) the location of the anticyclone (or cyclone) center determines the length of the fracture for certain patterns; and (iv) duration of weather conditions affects the width of the ice fracture zones. Movement of the ice pack on the leeward side of leads originating at promontories and islands increases, creating shear zones that control ice transport along the Alaska coast in winter. . Understanding how atmospheric conditions influence the large-scale motion of the ice pack is needed to design models that predict variability of the gyre and export of multi-year ice to lower latitudes.

Repeatability of the efficiency of columns packed with sub-3μm core-shell particles: Part II. 2.7 μm Halo-ES-Peptide-C18 particles in 4.6mm and 2.1mm×100mm column formats.

PubMed

Gritti, Fabrice; Guiochon, Georges

2012-08-24

The column-to-column repeatability of the mass transfer kinetics in columns packed with sub-3μm shell particles was investigated. The parameters of this kinetics were measured for twelve columns (six 2.1mm×100mm and six 4.6mm×100mm) packed with the same batch of 2.7μm Halo-ES-Peptide-C(18) particles (Advanced Material Technologies, Wilmington, DE, USA). For both series, the manufacturer provided columns at different positions in the efficiency distribution given by the quality test control. Three compounds were used, uracil, naphthalene and insulin. The reduced longitudinal diffusion term was measured with the peak parking (PP) method; the reduced solid-liquid mass transfer resistance term was given by a combination of the PP results and the most accurate model of effective diffusion in ternary composite materials (non-porous cores, concentric porous shell, and eluent matrix), validated previously. The overall eddy diffusion term was obtained by subtraction of these two HETP terms from the overall reduced HETP measured by numerical integration of the entire peak profiles. The results demonstrate that the dispersion of the column efficiencies is mostly due to the random nature of the packing process and the associated eddy diffusion term. At the highest reduced velocity achieved, the relative standard deviations (RSDs) of the eddy diffusion term for the 2.1mm I.D. columns were ca. 5 and 10% (with average values A(ν)=2.3 and 8.5) for naphthalene and uracil, respectively. For the 4.6mm I.D. columns, these RSDs were 3 and 5%, respectively, with average values A(ν)=1.5 and 2.7. Copyright © 2012 Elsevier B.V. All rights reserved.

Repeatability of the efficiency of columns packed with sub-3μm core-shell particles: Part I. 2.6μm Kinetex-C(18) particles in 4.6mm and 2.1mm×100mm column formats.

PubMed

Gritti, Fabrice; Guiochon, Georges

2012-08-24

The column-to-column repeatability of the mass transfer mechanism in columns packed with sub-3μm shell particles was investigated. The parameters of this mechanism were measured for twelve columns (six 2.1mm×100mm and six 4.6mm×100mm) packed with the same batch of 2.6μm Kinetex-C(18) particles (Phenomenex, CA, USA). For both series, the manufacturer provided columns at different positions in the efficiency distribution given by the quality test control. Three compounds were used, uracil, naphthalene and insulin. The reduced longitudinal diffusion term was measured with the peak parking (PP) method, the reduced solid-liquid mass transfer resistance term was given by a combination of the PP results and a model of effective diffusion in ternary composite materials (non-porous cores, concentric porous shell, and eluent matrix), validated previously. The overall eddy diffusion term was obtained by subtraction of these two HETP terms from the overall reduced HETP measured by numerical integration of the entire peak profiles. The results demonstrate that the dispersion of the column efficiencies is only due to the random nature of the packing process. At the highest reduced velocity achieved, the relative standard deviations (RSDs) of the eddy diffusion term for the 2.1mm I.D. columns were ca. 7% and 3% for the low molecular weight compounds and for insulin, respectively. For the 4.6mm I.D. columns, these RSDs were 15% and 5%, respectively. The larger RSDs for the 4.6mm I.D. columns is explained by the exceptionally low value of the eddy diffusion term. Copyright © 2012 Elsevier B.V. All rights reserved.

'Soothing the ring of fire': Australian women's and midwives' experiences of using perineal warm packs in the second stage of labour.

PubMed

Dahlen, Hannah G; Homer, Caroline S E; Cooke, Margaret; Upton, Alexis M; Nunn, Rosalie A; Brodrick, Belinda S

2009-04-01

to determine women's and midwives' experiences of using perineal warm packs in the second stage of labour. as part of a randomised controlled trial (Warm Pack Trial), women and midwives were asked to complete questionnaires about the effects of the warm packs on pain, perineal trauma, comfort, feelings of control, satisfaction and intentions for use during future births. two hospitals in Sydney, Australia. a randomised controlled trial was undertaken. In the late second stage of labour, nulliparous women (n=717) giving birth were randomly allocated to having warm packs (n=360) applied to their perineum or standard care (n=357). Standard care was defined as any second stage practice carried out by midwives that did not include the application of warm packs to the perineum. Three hundred and two nulliparous women randomised to receive warm packs (84%) received the treatment. Questionnaires were completed by 266 (88%) women who received warm packs, and 270 (89%) midwives who applied warm packs to these women. warm, moist packs were applied to the perineum in the late second stage of labour. warm packs were highly acceptable to both women and midwives as a means of relieving pain during the late second stage of labour. Almost the same number of women (79.7%) and midwives (80.4%) felt that the warm packs reduced perineal pain during the birth. Both midwives and women were positive about using warm packs in the future. The majority of women (85.7%) said that they would like to use perineal warm packs again for their next birth and would recommend them to friends (86.1%). Likewise, 91% of midwives were positive about using the warm packs, with 92.6% considering using them in the future as part of routine care in the second stage of labour. responses to questionnaires, eliciting experiences of women and midwives involved in the Warm Pack Trial, demonstrated that the practice of applying perineal warm packs in the late second stage of labour was highly acceptable and effective in helping to relieve perineal pain and increase comfort. perineal warm packs should be incorporated into second stage pain relief options available to women during childbirth.

Maximally dense packings of two-dimensional convex and concave noncircular particles.

PubMed

Atkinson, Steven; Jiao, Yang; Torquato, Salvatore

2012-09-01

Dense packings of hard particles have important applications in many fields, including condensed matter physics, discrete geometry, and cell biology. In this paper, we employ a stochastic search implementation of the Torquato-Jiao adaptive-shrinking-cell (ASC) optimization scheme [Nature (London) 460, 876 (2009)] to find maximally dense particle packings in d-dimensional Euclidean space R(d). While the original implementation was designed to study spheres and convex polyhedra in d≥3, our implementation focuses on d=2 and extends the algorithm to include both concave polygons and certain complex convex or concave nonpolygonal particle shapes. We verify the robustness of this packing protocol by successfully reproducing the known putative optimal packings of congruent copies of regular pentagons and octagons, then employ it to suggest dense packing arrangements of congruent copies of certain families of concave crosses, convex and concave curved triangles (incorporating shapes resembling the Mercedes-Benz logo), and "moonlike" shapes. Analytical constructions are determined subsequently to obtain the densest known packings of these particle shapes. For the examples considered, we find that the densest packings of both convex and concave particles with central symmetry are achieved by their corresponding optimal Bravais lattice packings; for particles lacking central symmetry, the densest packings obtained are nonlattice periodic packings, which are consistent with recently-proposed general organizing principles for hard particles. Moreover, we find that the densest known packings of certain curved triangles are periodic with a four-particle basis, and we find that the densest known periodic packings of certain moonlike shapes possess no inherent symmetries. Our work adds to the growing evidence that particle shape can be used as a tuning parameter to achieve a diversity of packing structures.

Maximally dense packings of two-dimensional convex and concave noncircular particles

NASA Astrophysics Data System (ADS)

Atkinson, Steven; Jiao, Yang; Torquato, Salvatore

2012-09-01

Dense packings of hard particles have important applications in many fields, including condensed matter physics, discrete geometry, and cell biology. In this paper, we employ a stochastic search implementation of the Torquato-Jiao adaptive-shrinking-cell (ASC) optimization scheme [Nature (London)NATUAS0028-083610.1038/nature08239 460, 876 (2009)] to find maximally dense particle packings in d-dimensional Euclidean space Rd. While the original implementation was designed to study spheres and convex polyhedra in d≥3, our implementation focuses on d=2 and extends the algorithm to include both concave polygons and certain complex convex or concave nonpolygonal particle shapes. We verify the robustness of this packing protocol by successfully reproducing the known putative optimal packings of congruent copies of regular pentagons and octagons, then employ it to suggest dense packing arrangements of congruent copies of certain families of concave crosses, convex and concave curved triangles (incorporating shapes resembling the Mercedes-Benz logo), and “moonlike” shapes. Analytical constructions are determined subsequently to obtain the densest known packings of these particle shapes. For the examples considered, we find that the densest packings of both convex and concave particles with central symmetry are achieved by their corresponding optimal Bravais lattice packings; for particles lacking central symmetry, the densest packings obtained are nonlattice periodic packings, which are consistent with recently-proposed general organizing principles for hard particles. Moreover, we find that the densest known packings of certain curved triangles are periodic with a four-particle basis, and we find that the densest known periodic packings of certain moonlike shapes possess no inherent symmetries. Our work adds to the growing evidence that particle shape can be used as a tuning parameter to achieve a diversity of packing structures.

Territoriality and inter-pack aggression in gray wolves: shaping a social carnivore's life history

USGS Publications Warehouse

Cassidy, Kira A.; Smith, Douglas W.; Mech, L. David; MacNulty, Daniel R.; Stahler, Daniel R.; Metz, Matthew C.

2016-01-01

When Rudyard Kipling wrote The Jungle Book in 1894 and included the famous line "For the strength of the Wolf is the Pack, and the strength of the Pack is the Wolf," he would have had no idea that over a century later, scientific research would back up his poetic phrase. Recent studies in Yellowstone have found that both the individual wolf and the collective pack rely on each other and play important roles in territoriality. At a time when most fairy tales and fables were portraying wolves as demonic killers or, at best, slapstick gluttons, Kipling seemed to have a respect or even reverence for the wolf. Wolves in The Jungle Book raise and mentor the main character Mowgli, with the pack's leader eventually dying to save the "man-cub" from a pack of wolves. Kipling may have extended intra- pack benevolence to a human boy for literary sake, but he was clearly enthralled with how pack members treat each other. As wolf packs are almost always family units, most commonly comprised of a breeding pair and their offspring from several years, amiable behavior within the pack is unsurprising. By contrast, wolf packs are fiercely intolerant of their neighbors, their rivals. And this competition is proving to be an important facet in the life of a wolf and its pack.

Packing Fraction of a Two-dimensional Eden Model with Random-Sized Particles

NASA Astrophysics Data System (ADS)

Kobayashi, Naoki; Yamazaki, Hiroshi

2018-01-01

We have performed a numerical simulation of a two-dimensional Eden model with random-size particles. In the present model, the particle radii are generated from a Gaussian distribution with mean μ and standard deviation σ. First, we have examined the bulk packing fraction for the Eden cluster and investigated the effects of the standard deviation and the total number of particles NT. We show that the bulk packing fraction depends on the number of particles and the standard deviation. In particular, for the dependence on the standard deviation, we have determined the asymptotic value of the bulk packing fraction in the limit of the dimensionless standard deviation. This value is larger than the packing fraction obtained in a previous study of the Eden model with uniform-size particles. Secondly, we have investigated the packing fraction of the entire Eden cluster including the effect of the interface fluctuation. We find that the entire packing fraction depends on the number of particles while it is independent of the standard deviation, in contrast to the bulk packing fraction. In a similar way to the bulk packing fraction, we have obtained the asymptotic value of the entire packing fraction in the limit NT → ∞. The obtained value of the entire packing fraction is smaller than that of the bulk value. This fact suggests that the interface fluctuation of the Eden cluster influences the packing fraction.

27 CFR 24.308 - Bottled or packed wine record.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Bottled or packed wine... BUREAU, DEPARTMENT OF THE TREASURY LIQUORS WINE Records and Reports § 24.308 Bottled or packed wine record. A proprietor who bottles, packs, or receives bottled or packed beverage wine in bond shall...

SimPackJ/S: a web-oriented toolkit for discrete event simulation

NASA Astrophysics Data System (ADS)

Park, Minho; Fishwick, Paul A.

2002-07-01

SimPackJ/S is the JavaScript and Java version of SimPack, which means SimPackJ/S is a collection of JavaScript and Java libraries and executable programs for computer simulations. The main purpose of creating SimPackJ/S is that we allow existing SimPack users to expand simulation areas and provide future users with a freeware simulation toolkit to simulate and model a system in web environments. One of the goals for this paper is to introduce SimPackJ/S. The other goal is to propose translation rules for converting C to JavaScript and Java. Most parts demonstrate the translation rules with examples. In addition, we discuss a 3D dynamic system model and overview an approach to 3D dynamic systems using SimPackJ/S. We explain an interface between SimPackJ/S and the 3D language--Virtual Reality Modeling Language (VRML). This paper documents how to translate C to JavaScript and Java and how to utilize SimPackJ/S within a 3D web environment.

Multi-Node Thermal System Model for Lithium-Ion Battery Packs: Preprint

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Ying; Smith, Kandler; Wood, Eric

Temperature is one of the main factors that controls the degradation in lithium ion batteries. Accurate knowledge and control of cell temperatures in a pack helps the battery management system (BMS) to maximize cell utilization and ensure pack safety and service life. In a pack with arrays of cells, a cells temperature is not only affected by its own thermal characteristics but also by its neighbors, the cooling system and pack configuration, which increase the noise level and the complexity of cell temperatures prediction. This work proposes to model lithium ion packs thermal behavior using a multi-node thermal network model,more » which predicts the cell temperatures by zones. The model was parametrized and validated using commercial lithium-ion battery packs. neighbors, the cooling system and pack configuration, which increase the noise level and the complexity of cell temperatures prediction. This work proposes to model lithium ion packs thermal behavior using a multi-node thermal network model, which predicts the cell temperatures by zones. The model was parametrized and validated using commercial lithium-ion battery packs.« less

Comparing the efficacy of mature mud pack and hot pack treatments for knee osteoarthritis.

PubMed

Sarsan, Ayşe; Akkaya, Nuray; Ozgen, Merih; Yildiz, Necmettin; Atalay, Nilgun Simsir; Ardic, Fusun

2012-01-01

The objective of this study is to compare the efficacy of mature mud pack and hot pack therapies on patients with knee osteoarthritis. This study was designed as a prospective, randomized-controlled, and single-blinded clinical trial. Twenty-seven patients with clinical and radiologic evidence of knee osteoarthritis were randomly assigned into two groups and were treated with mature mud packs (n 15) or hot packs (n=12). Patients were evaluated for pain [based on the visual analog scale (VAS)], function (WOMAC, 6 min walking distance), quality of life [Short Form-36 (SF-36)], and serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and insulin-like growth factor-1 (IGF-1) at baseline, post-treatment, and 3 and 6~months after treatment. The mud pack group shows a significant improvement in VAS, pain, stifness, and physical function domains of WOMAC. The difference between groups of pain and physical activity domains is significant at post-treatment in favor of mud pack. For a 6 min walking distance, mud pack shows significant improvement, and the difference is significant between groups in favor of mud pack at post-treatment and 3 and 6 months after treatment. Mud pack shows significant improvement in the pain subscale of SF-36 at the third month continuing until the sixth month after the treatment. Significant improvements are found for the social function, vitality/energy, physical role disability, and general health subscales of SF-36 in favor of the mud pack compared with the hot pack group at post-treatment. A significant increase is detected for IGF-1 in the mud pack group 3 months after treatment compared with the baseline, and the difference is significant between groups 3 months after the treatment. Mud pack is a favorable option compared with hotpack for pain relief and for the improvement of functional conditions in treating patients with knee osteoarthritis.

The retail display life of steaks prepared from chill stored vacuum and carbon dioxide-packed sub-primal beef cuts.

PubMed

Bell, R G; Penney, N; Moorhead, S M

1996-01-01

Chilled striploins and cube rolls from ten Australian steers (grain-fed for 150 days) were trimmed of external fat and cut transversely into portions approximately 10 cm thick, each weighing between 750 and 1000 g. These 'retailer-ready' cuts were each wrapped in drip saver pads and slid inside a plastic sleeve before being individually placed into a clear plastic high oxygen barrier film, metallized film or conventional vacuum bag. Cuts in clear plastic and metallized film packs were packaged in an oxygen-free saturated carbon dioxide atmosphere (CO(2)-CAP), those in vacuum bags were conventionally vacuum-packed. All packs were returned to the chiller for further cooling. After 24 hr, half the clear plastic and metallized CO(2)-CAP packs were carbon dioxide master-packed in groups of eight. Retailer-ready cuts in both clear plastic and metallized film single unit and master-packed CO(2)-CAP packs were air freighted to New Zealand and sea freighted to Japan for assessment. The control vacuum packs were all consigned to New Zealand. Assessments in both countries after 39-89 days storage at between 0 °C and -1.0 °C indicated that fat colour stability limited the retail display life of steaks cut from meat in these retailer-ready packs to approximately 48 hr. In this regard, meat from single unit CO(2)-CAP, master pack CO(2)-CAP and vacuum packs performed similarly. Lean meat colour and sensory attributes remained acceptable for up to 48 hr after displayed product was rejected because of grey-green fat discoloration. The microbiological status of retailer-ready cuts removed from CO(2)-CAP packs after 89 days chilled storage was superior to that of cuts from vacuum packs. Clear plastic and metallized film CO(2)-CAP packs performed comparably.

Electrocauterization and no packing may be comparable with nasal packing for postoperative hemorrhage after endoscopic sinus surgery.

PubMed

Kim, Dong-Kyu; Rhee, Chae Seo; Kim, Jeong-Whun

2016-05-01

Nasal packing is commonly performed after functional endoscopic sinus surgery (FESS). However, nasal packing is associated with higher cost (owing to the cost of packing materials), patient discomfort, delayed wound healing, and concern about toxic shock syndrome. Some surgeons have been performing FESS without packing, but there are few studies that show its safety. The purpose of this study was to evaluate the safety of electrocauterization and no packing. A total of 490 patients who underwent bilateral FESS for chronic rhinosinusitis were included in this retrospective study, 242 in the nasal packing group and 248 in the electrocauterization and no-packing group. Electrocauterization was performed by using a suction coagulator. Rates of immediate (first 24 hours after surgery) and delayed postoperative bleeding were compared. Patient characteristics, including concomitant disease and medication history, and Lund-Mackay computed tomography score were also assessed Results: There were no significant differences in age; sex; Lund-Mackay score; use of anticoagulant drugs; or prevalence of hypertension, diabetes, or asthma between the two groups. In the electrocauterization and no-packing group, there were fewer patients with allergic rhinitis and more smokers. Primary bleeding did not occur in the nasal packing group, but 11 patients (4.4%) had delayed bleeding. Primary bleeding occurred in four patients (1.7%) in the electrocauterization and no-packing group, and five patients (2.1%) had delayed bleeding. There were no significant differences in primary (p = 0.058) and secondary bleeding (p = 0.142) between the two groups. All bleeding was minor and easily controlled. Multivariate logistic regression analysis ruled out significant correlation between no packing and postoperative bleeding. This study provided evidence that, in terms of postoperative hemorrhage, the safety of the electrocauterization and no-packing technique after FESS was comparable with that of nasal packing.

2-Phenyl-4,5-di-2-pyridyl-1H-imidazole

PubMed Central

Felsmann, Marika; Schindler, Diana; Weber, Edwin

2010-01-01

In the title compound, C19H14N4, which was crystallized from dimethyl sulfoxide, the arene and heterocyclic rings of the lophine analogue framework differ only slightly from coplanarity (dihedral angles range from 8.8 to 20.2°), and intramolecular N—H⋯N and C—H⋯N interactions help to establish the conformation. The crystal packing features a number of weak C—H⋯N, N—H⋯N hydrogen-bond type contacts, and C—H⋯π interactions, leading to the formation of a herringbone structure. PMID:21580039

Fabrication of Microstripline Wiring for Large Format Transition Edge Sensor Arrays

NASA Technical Reports Server (NTRS)

Chervenak, James A.; Adams, J. M.; Bailey, C. N.; Bandler, S.; Brekosky, R. P.; Eckart, M. E.; Erwin, A. E.; Finkbeiner, F. M.; Kelley, R. L.; Kilbourne, C. A.;

Design of a prototype flow microreactor for synthetic biology in vitro.

PubMed

Boehm, Christian R; Freemont, Paul S; Ces, Oscar

2013-09-07

As a reference platform for in vitro synthetic biology, we have developed a prototype flow microreactor for enzymatic biosynthesis. We report the design, implementation, and computer-aided optimisation of a three-step model pathway within a microfluidic reactor. A packed bed format was shown to be optimal for enzyme compartmentalisation after experimental evaluation of several approaches. The specific substrate conversion efficiency could significantly be improved by an optimised parameter set obtained by computational modelling. Our microreactor design provides a platform to explore new in vitro synthetic biology solutions for industrial biosynthesis.

New technique for heterogeneous vapor-phase synthesis of nanostructured metal layers from low-dimensional volatile metal complexes

NASA Astrophysics Data System (ADS)

Badalyan, A. M.; Bakhturova, L. F.; Kaichev, V. V.; Polyakov, O. V.; Pchelyakov, O. P.; Smirnov, G. I.

2011-09-01

A new technique for depositing thin nanostructured layers on semiconductor and insulating substrates that is based on heterogeneous gas-phase synthesis from low-dimensional volatile metal complexes is suggested and tried out. Thin nanostructured copper layers are deposited on silicon and quartz substrates from low-dimensional formate complexes using a combined synthesis-mass transport process. It is found that copper in layers thus deposited is largely in a metal state (Cu0) and has the form of closely packed nanograins with a characteristic structure.

Brush seals for turbine engine fuel conservation

NASA Astrophysics Data System (ADS)

Sousa, Mike

1994-07-01

The program objective is to demonstrate brush seals for replacing labyrinth seals in turboprop engines. The approach taken was to design and procure brush seals with assistance from Sealol, modify and instrument an existing T407 low pressure turbine test rig, replace inner balance piston and outer balance piston labyrinth seals with brush seals, conduct cyclic tests to evaluate seal leakage at operating pressures and temperatures, and evaluate effect of seal pack width and rotor eccentricity. Results are presented in viewgraph format and show that brush seals offer performance advantages over labyrinth seals.

High temperature surface protection. [10 gas turbines

NASA Technical Reports Server (NTRS)

Levine, S. R.

1978-01-01

Alloys of the MCrAlX type are the basis for high temperature surface protection systems in gas turbines. M can be one or more of Ni, Co, or Fe and X denotes a reactive metal added to enhance oxide scale adherence. The selection and formation as well as the oxidation, hot corrosion and thermal fatigue performance of MCrAlX coatings are discussed. Coatings covered range from simple aluminides formed by pack cementation to the more advanced physical vapor deposition overlay coatings and developmental plasma spray deposited thermal barrier coatings.

Packing and deploying Soft Origami to and from cylindrical volumes with application to automotive airbags

PubMed Central

Nelson, Todd G.; Zimmerman, Trent K.; Fernelius, Janette D.; Magleby, Spencer P.; Howell, Larry L.

2016-01-01

Packing soft-sheet materials of approximately zero bending stiffness using Soft Origami (origami patterns applied to soft-sheet materials) into cylindrical volumes and their deployment via mechanisms or internal pressure (inflation) is of interest in fields including automobile airbags, deployable heart stents, inflatable space habitats, and dirigible and parachute packing. This paper explores twofold patterns, the ‘flasher’ and the ‘inverted-cone fold’, for packing soft-sheet materials into cylindrical volumes. Two initial packing methods and mechanisms are examined for each of the flasher and inverted-cone fold patterns. An application to driver’s side automobile airbags is performed, and deployment tests are completed to compare the influence of packing method and origami pattern on deployment performance. Following deployment tests, two additional packing methods for the inverted-cone fold pattern are explored and applied to automobile airbags. It is shown that modifying the packing method (using different methods to impose the same base pattern on the soft-sheet material) can lead to different deployment performance. In total, two origami patterns and six packing methods are examined, and the benefits of using Soft Origami patterns and packing methods are discussed. Soft Origami is presented as a viable method for efficiently packing soft-sheet materials into cylindrical volumes. PMID:27703707

Microstructural characterization of random packings of cubic particles

PubMed Central

Malmir, Hessam; Sahimi, Muhammad; Tabar, M. Reza Rahimi

2016-01-01

Understanding the properties of random packings of solid objects is of critical importance to a wide variety of fundamental scientific and practical problems. The great majority of the previous works focused, however, on packings of spherical and sphere-like particles. We report the first detailed simulation and characterization of packings of non-overlapping cubic particles. Such packings arise in a variety of problems, ranging from biological materials, to colloids and fabrication of porous scaffolds using salt powders. In addition, packing of cubic salt crystals arise in various problems involving preservation of pavements, paintings, and historical monuments, mineral-fluid interactions, CO2 sequestration in rock, and intrusion of groundwater aquifers by saline water. Not much is known, however, about the structure and statistical descriptors of such packings. We have developed a version of the random sequential addition algorithm to generate such packings, and have computed a variety of microstructural descriptors, including the radial distribution function, two-point probability function, orientational correlation function, specific surface, and mean chord length, and have studied the effect of finite system size and porosity on such characteristics. The results indicate the existence of both spatial and orientational long-range order in the packing, which is more distinctive for higher packing densities. The maximum packing fraction is about 0.57. PMID:27725736

Packing and deploying Soft Origami to and from cylindrical volumes with application to automotive airbags

NASA Astrophysics Data System (ADS)

Bruton, Jared T.; Nelson, Todd G.; Zimmerman, Trent K.; Fernelius, Janette D.; Magleby, Spencer P.; Howell, Larry L.

2016-09-01

Packing soft-sheet materials of approximately zero bending stiffness using Soft Origami (origami patterns applied to soft-sheet materials) into cylindrical volumes and their deployment via mechanisms or internal pressure (inflation) is of interest in fields including automobile airbags, deployable heart stents, inflatable space habitats, and dirigible and parachute packing. This paper explores twofold patterns, the `flasher' and the `inverted-cone fold', for packing soft-sheet materials into cylindrical volumes. Two initial packing methods and mechanisms are examined for each of the flasher and inverted-cone fold patterns. An application to driver's side automobile airbags is performed, and deployment tests are completed to compare the influence of packing method and origami pattern on deployment performance. Following deployment tests, two additional packing methods for the inverted-cone fold pattern are explored and applied to automobile airbags. It is shown that modifying the packing method (using different methods to impose the same base pattern on the soft-sheet material) can lead to different deployment performance. In total, two origami patterns and six packing methods are examined, and the benefits of using Soft Origami patterns and packing methods are discussed. Soft Origami is presented as a viable method for efficiently packing soft-sheet materials into cylindrical volumes.

The effect of nanoparticle packing on capacitive electrode performance.

PubMed

Lee, Younghee; Noh, Seonmyeong; Kim, Min-Sik; Kong, Hye Jeong; Im, Kyungun; Kwon, Oh Seok; Kim, Sungmin; Yoon, Hyeonseok

2016-06-09

Nanoparticles pack together to form macro-scale electrodes in various types of devices, and thus, optimization of the nanoparticle packing is a prerequisite for the realization of a desirable device performance. In this work, we provide in-depth insight into the effect of nanoparticle packing on the performance of nanoparticle-based electrodes by combining experimental and computational findings. As a model system, polypyrrole nanospheres of three different diameters were used to construct pseudocapacitive electrodes, and the performance of the electrodes was examined at various nanosphere diameter ratios and mixed weight fractions. Two numerical algorithms are proposed to simulate the random packing of the nanospheres on the electrode. The binary nanospheres exhibited diverse, complicated packing behaviors compared with the monophasic packing of each nanosphere species. The packing of the two nanosphere species with lower diameter ratios at an optimized composition could lead to more dense packing of the nanospheres, which in turn could contribute to better device performance. The dense packing of the nanospheres would provide more efficient transport pathways for ions because of the reduced inter-nanosphere pore size and enlarged surface area for charge storage. Ultimately, it is anticipated that our approach can be widely used to define the concept of "the best nanoparticle packing" for desirable device performance.

Packing and deploying Soft Origami to and from cylindrical volumes with application to automotive airbags.

PubMed

Bruton, Jared T; Nelson, Todd G; Zimmerman, Trent K; Fernelius, Janette D; Magleby, Spencer P; Howell, Larry L

2016-09-01

Packing soft-sheet materials of approximately zero bending stiffness using Soft Origami (origami patterns applied to soft-sheet materials) into cylindrical volumes and their deployment via mechanisms or internal pressure (inflation) is of interest in fields including automobile airbags, deployable heart stents, inflatable space habitats, and dirigible and parachute packing. This paper explores twofold patterns, the 'flasher' and the 'inverted-cone fold', for packing soft-sheet materials into cylindrical volumes. Two initial packing methods and mechanisms are examined for each of the flasher and inverted-cone fold patterns. An application to driver's side automobile airbags is performed, and deployment tests are completed to compare the influence of packing method and origami pattern on deployment performance. Following deployment tests, two additional packing methods for the inverted-cone fold pattern are explored and applied to automobile airbags. It is shown that modifying the packing method (using different methods to impose the same base pattern on the soft-sheet material) can lead to different deployment performance. In total, two origami patterns and six packing methods are examined, and the benefits of using Soft Origami patterns and packing methods are discussed. Soft Origami is presented as a viable method for efficiently packing soft-sheet materials into cylindrical volumes.

Confined disordered strictly jammed binary sphere packings

NASA Astrophysics Data System (ADS)

Chen, D.; Torquato, S.

2015-12-01

Disordered jammed packings under confinement have received considerably less attention than their bulk counterparts and yet arise in a variety of practical situations. In this work, we study binary sphere packings that are confined between two parallel hard planes and generalize the Torquato-Jiao (TJ) sequential linear programming algorithm [Phys. Rev. E 82, 061302 (2010), 10.1103/PhysRevE.82.061302] to obtain putative maximally random jammed (MRJ) packings that are exactly isostatic with high fidelity over a large range of plane separation distances H , small to large sphere radius ratio α , and small sphere relative concentration x . We find that packing characteristics can be substantially different from their bulk analogs, which is due to what we term "confinement frustration." Rattlers in confined packings are generally more prevalent than those in their bulk counterparts. We observe that packing fraction, rattler fraction, and degree of disorder of MRJ packings generally increase with H , though exceptions exist. Discontinuities in the packing characteristics as H varies in the vicinity of certain values of H are due to associated discontinuous transitions between different jammed states. When the plane separation distance is on the order of two large-sphere diameters or less, the packings exhibit salient two-dimensional features; when the plane separation distance exceeds about 30 large-sphere diameters, the packings approach three-dimensional bulk packings. As the size contrast increases (as α decreases), the rattler fraction dramatically increases due to what we call "size-disparity" frustration. We find that at intermediate α and when x is about 0.5 (50-50 mixture), the disorder of packings is maximized, as measured by an order metric ψ that is based on the number density fluctuations in the direction perpendicular to the hard walls. We also apply the local volume-fraction variance στ2(R ) to characterize confined packings and find that these packings possess essentially the same level of hyperuniformity as their bulk counterparts. Our findings are generally relevant to confined packings that arise in biology (e.g., structural color in birds and insects) and may have implications for the creation of high-density powders and improved battery designs.

Microextraction by packed sorbent: an emerging, selective and high-throughput extraction technique in bioanalysis.

PubMed

Pereira, Jorge; Câmara, José S; Colmsjö, Anders; Abdel-Rehim, Mohamed

2014-06-01

Sample preparation is an important analytical step regarding the isolation and concentration of desired components from complex matrices and greatly influences their reliable and accurate analysis and data quality. It is the most labor-intensive and error-prone process in analytical methodology and, therefore, may influence the analytical performance of the target analytes quantification. Many conventional sample preparation methods are relatively complicated, involving time-consuming procedures and requiring large volumes of organic solvents. Recent trends in sample preparation include miniaturization, automation, high-throughput performance, on-line coupling with analytical instruments and low-cost operation through extremely low volume or no solvent consumption. Micro-extraction techniques, such as micro-extraction by packed sorbent (MEPS), have these advantages over the traditional techniques. This paper gives an overview of MEPS technique, including the role of sample preparation in bioanalysis, the MEPS description namely MEPS formats (on- and off-line), sorbents, experimental and protocols, factors that affect the MEPS performance, and the major advantages and limitations of MEPS compared with other sample preparation techniques. We also summarize MEPS recent applications in bioanalysis. Copyright © 2014 John Wiley & Sons, Ltd.

Characteristics of large three-dimensional heaps of particles produced by ballistic deposition from extended sources

NASA Astrophysics Data System (ADS)

Topic, Nikola; Gallas, Jason A. C.; Pöschel, Thorsten

2013-11-01

This paper reports a detailed numerical investigation of the geometrical and structural properties of three-dimensional heaps of particles. Our goal is the characterization of very large heaps produced by ballistic deposition from extended circular dropping areas. First, we provide an in-depth study of the formation of monodisperse heaps of particles. We find very large heaps to contain three new geometrical characteristics: they may display two external angles of repose, one internal angle of repose, and four distinct packing fraction (density) regions. Such features are found to be directly connected with the size of the dropping zone. We derive a differential equation describing the boundary of an unexpected triangular packing fraction zone formed under the dropping area. We investigate the impact that noise during the deposition has on the final heap structure. In addition, we perform two complementary experiments designed to test the robustness of the novel features found. The first experiment considers changes due to polydispersity. The second checks what happens when letting the extended dropping zone to become a point-like source of particles, the more common type of source.

Chirality Transfer and Modulation in LB Films Derived From the Diacetylene/Melamine Hydrogen-Bonded Complex.

PubMed

Zhu, Yu; Xu, Yangyang; Zou, Gang; Zhang, Qijin

2015-08-01

Introduction of hydrogen-bonding interaction into π-conjugated systems is a promising strategy, since the highly selective and directional hydrogen-bonding can increase the binding strength, provide enhanced stability to the assemblies, and position the π-conjugated molecules in a desired arrangement. The helical packing of the rigid melamine cores seems to play a dominating role in the subsequent formation of the peripheral helical PDA backbone. The polymerized Langmuir-Blodgett (LB) films exhibited reversible colorimetric and chiroptical changes during repeated heating-cooling cycles, which should be ascribed to the strong hydrogen-bonding interaction between the carboxylic acid and the melamine core. Further, the closely helical packing of the melamine cores could be destroyed upon exposure to HCl or NH(3) gas, whereas the peripheral helical polyaniline and polydiacetylene (PDA) backbone exhibited excellent stability. Although similar absorption changes could be observed for the films upon exposure to HCl or NH(3) gas, their distinct circular dichroism (CD) responses enabled us to distinguish the above two stimuli. © 2015 Wiley Periodicals, Inc.

Gel-based morphological design of zirconium metal-organic frameworks.

PubMed

Bueken, Bart; Van Velthoven, Niels; Willhammar, Tom; Stassin, Timothée; Stassen, Ivo; Keen, David A; Baron, Gino V; Denayer, Joeri F M; Ameloot, Rob; Bals, Sara; De Vos, Dirk; Bennett, Thomas D

2017-05-01

The ability of metal-organic frameworks (MOFs) to gelate under specific synthetic conditions opens up new opportunities in the preparation and shaping of hierarchically porous MOF monoliths, which could be directly implemented for catalytic and adsorptive applications. In this work, we present the first examples of xero- or aerogel monoliths consisting solely of nanoparticles of several prototypical Zr 4+ -based MOFs: UiO-66-X (X = H, NH 2 , NO 2 , (OH) 2 ), UiO-67, MOF-801, MOF-808 and NU-1000. High reactant and water concentrations during synthesis were observed to induce the formation of gels, which were converted to monolithic materials by drying in air or supercritical CO 2 . Electron microscopy, combined with N 2 physisorption experiments, was used to show that irregular nanoparticle packing leads to pure MOF monoliths with hierarchical pore systems, featuring both intraparticle micropores and interparticle mesopores. Finally, UiO-66 gels were shaped into monolithic spheres of 600 μm diameter using an oil-drop method, creating promising candidates for packed-bed catalytic or adsorptive applications, where hierarchical pore systems can greatly mitigate mass transfer limitations.

Nogo goes in the pure water: solution structure of Nogo-60 and design of the structured and buffer-soluble Nogo-54 for enhancing CNS regeneration.

PubMed

Li, Minfen; Liu, Jingxian; Song, Jianxing

2006-08-01

The inability to determine the structure of the buffer-insoluble Nogo extracellular domain retarded further design of Nogo receptor (NgR) antagonists to treat CNS axonal injuries. Very surprisingly, we recently discovered that Nogo-60 was soluble and structured in salt-free water, thus allowing the determination of the first Nogo structure by heteronuclear NMR spectroscopy. Nogo-60 adopts an unusual helical structure with the N- and C-terminal helices connected by a long middle helix. While the N-helix has no contact with the rest of the molecule, the C-helix flips back to pack against the 20-residue middle helix. This packing appears to trigger the formation of the stable Nogo-60 structure because Nogo-40 with the last helix truncated is unstructured. The Nogo-60 structure offered us rationales for further design of the structured and buffer-soluble Nogo-54, which may be used as a novel NgR antagonist. Furthermore, our discovery may imply a general solution to solubilizing a category of buffer-insoluble proteins for urgent structural investigations.

Percolation of disordered jammed sphere packings

NASA Astrophysics Data System (ADS)

Ziff, Robert M.; Torquato, Salvatore

2017-02-01

We determine the site and bond percolation thresholds for a system of disordered jammed sphere packings in the maximally random jammed state, generated by the Torquato-Jiao algorithm. For the site threshold, which gives the fraction of conducting versus non-conducting spheres necessary for percolation, we find {{p}\\text{c}}=0.3116(3) , consistent with the 1979 value of Powell 0.310(5) and identical within errors to the threshold for the simple-cubic lattice, 0.311 608, which shares the same average coordination number of 6. In terms of the volume fraction ϕ, the threshold corresponds to a critical value {φ\\text{c}}=0.199 . For the bond threshold, which apparently was not measured before, we find {{p}\\text{c}}=0.2424(3) . To find these thresholds, we considered two shape-dependent universal ratios involving the size of the largest cluster, fluctuations in that size, and the second moment of the size distribution; we confirmed the ratios’ universality by also studying the simple-cubic lattice with a similar cubic boundary. The results are applicable to many problems including conductivity in random mixtures, glass formation, and drug loading in pharmaceutical tablets.

Tablet compression tooling - Impact of punch face edge modification.

PubMed

Anbalagan, Parthiban; Heng, Paul Wan Sia; Liew, Celine Valeria

2017-05-30

The influence of punch face edge geometry modification on tablet compression and the properties of the resultant tablets produced on a rotary press were investigated. The results revealed that tablets produced from the punches with radius edge face geometry consistently displayed better physical quality; higher tensile strength and lower capping tendency. Modification of the angled edge of the bevel face to the curved edge of the radius face, enabled deeper punch penetration in the die cavity during the compression cycle, bringing about greater compact densification. Improved die fill packing increased interparticulate bond formation and helped to dissipate destructive elasticity within the compact, consequently reduced tablet expansion during the decompression phase. The positive impact of punch face edge modification was also more noticeable at a higher turret speed. The application of the precompression force along with dwell time extension amplified the tableting performance of radius edge punch face design to a greater extent when compared to bevel edge punch face design. This could be attributed to the enhanced packing efficiency at both precompression and main compression stages. Copyright © 2017 Elsevier B.V. All rights reserved.

A triclinic polymorph of tri­cyclo­hexyl­phosphane sulfide: crystal structure and Hirshfeld surface analysis

PubMed Central

Tan, Yi Jiun; Yeo, Chien Ing; Halcovitch, Nathan R.; Jotani, Mukesh M.

2017-01-01

The title compound, (C6H11)3PS (systematic name: tri­cyclo­hexyl-λ5-phosphane­thione), is a triclinic (P-1, Z′ = 1) polymorph of the previously reported ortho­rhom­bic form (Pnma, Z′ = 1/2) [Kerr et al. (1977 ▸). Can. J. Chem. 55, 3081–3085; Reibenspies et al. (1996 ▸). Z. Kristallogr. 211, 400]. While conformational differences exist between the non-symmetric mol­ecule in the triclinic polymorph, cf. the mirror-symmetric mol­ecule in the ortho­rhom­bic form, these differences are not chemically significant. The major feature of the mol­ecular packing in the triclinic polymorph is the formation of linear chains along the a axis sustained by methine-C—H⋯S(thione) inter­actions. The chains pack with no directional inter­actions between them. The analysis of the Hirshfeld surface for both polymorphs indicates a high degree of similarity, being dominated by H⋯H (ca 90%) and S⋯H/H⋯S contacts. PMID:28435705

Electrophobic interaction induced impurity clustering in metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Hong-Bo; Wang, Jin-Long; Jiang, W.

2016-10-01

We introduce the concept of electrophobic interaction, analogous to hydrophobic interaction, for describing the behavior of impurity atoms in a metal, a 'solvent of electrons'. We demonstrate that there exists a form of electrophobic interaction between impurities with closed electron shell structure, which governs their dissolution behavior in a metal. Using He, Be and Ar as examples, we predict by first-principles calculations that the electrophobic interaction drives He, Be or Ar to form a close-packed cluster with a clustering energy that follows a universal power-law scaling with the number of atoms (N) dissolved in a free electron gas, as wellmore » as W or Al lattice, as Ec is proportional to (N2/3-N). This new concept unifies the explanation for a series of experimental observations of close-packed inert-gas bubble formation in metals, and significantly advances our fundamental understanding and capacity to predict the solute behavior of impurities in metals, a useful contribution to be considered in future material design of metals for nuclear, metallurgical, and energy applications.« less

The performance of biological anaerobic filters packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) during the restart period: effect of the C/N ratios and filter media.

PubMed

Yue, Qinyan; Han, Shuxin; Yue, Min; Gao, Baoyu; Li, Qian; Yu, Hui; Zhao, Yaqin; Qi, Yuanfeng

2009-11-01

Two lab-scale upflow biological anaerobic filters (BAF) packed with sludge-fly ash ceramic particles (SFCP) and commercial ceramic particles (CCP) were employed to investigate effects of the C/N ratios and filter media on the BAF performance during the restart period. The results indicated that BAF could be restarted normally after one-month cease. The C/N ratio of 4.0 was the thresholds of nitrate removal and nitrite accumulation. TN removal and phosphate uptake reached the maximum value at the same C/N ratio of 5.5. Ammonia formation was also found and excreted a negative influence on TN removal, especially when higher C/N ratios were applied. Nutrients were mainly degraded within the height of 25 cm from the bottom. In addition, SFCP, as novel filter media manufactured by wastes-dewatered sludge and fly ash, represented a better potential in inhibiting nitrite accumulation, TN removal and phosphate uptake due to their special characteristics in comparison with CCP.

Structure of Arabidopsis thaliana Rubisco activase.

PubMed

Hasse, Dirk; Larsson, Anna M; Andersson, Inger

2015-04-01

The CO2-fixing enzyme ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is inactivated by the formation of dead-end complexes with inhibitory sugar phosphates. In plants and green algae, the ATP-dependent motor protein Rubisco activase restores catalytic competence by facilitating conformational changes in Rubisco that promote the release of the inhibitory compounds from the active site. Here, the crystal structure of Rubisco activase from Arabidopsis thaliana is presented at 2.9 Å resolution. The structure reveals an AAA+ two-domain structure. More than 100 residues in the protein were not visible in the electron-density map owing to conformational disorder, but were verified to be present in the crystal by mass spectrometry. Two sulfate ions were found in the structure. One was bound in the loop formed by the Walker A motif at the interface of the domains. A second sulfate ion was bound at the N-terminal end of the first helix of the C-terminal domain. The protein packs in a helical fashion in the crystal, as observed previously for Rubisco activase, but differences in the helical pitch indicate flexibility in the packing of the protein.

Synthesis, crystal growth, structural and physicochemical studies of novel binary organic complex: 4-chloroaniline-3-hydroxy-4-methoxybenzaldehyde

NASA Astrophysics Data System (ADS)

Sharma, K. P.; Reddi, R. S. B.; Bhattacharya, S.; Rai, R. N.

2012-06-01

The solid-state reaction, which is solvent free and green synthesis, has been adopted to explore the novel compound. The phase diagram of 4-chloroaniline (CA) and 3-hydroxy-4-methoxybenzaldehyde (HMB) system shows the formation of a novel 1:1 molecular complex, and two eutectics on either sides of complex. Thermochemical studies of complex and eutectics have been carried out for various properties such as heat of fusion, entropy of fusion, Jackson's parameters, interfacial energy and excess thermodynamic functions. The formation of molecular complex was also studied by IR, NMR, elemental analysis and UV-Vis absorption spectra. The single crystal of molecular complex was grown and its XRD study confirms the formation of complex and identifies the crystal structure and atomic packing of crystal of complex. Transmission spectra of grown crystal of the complex show 70% transmittance efficiency with cut off wavelength 412 nm. The band gap and refractive index of the crystal of complex have also been studied.

Clustering on Magnesium Surfaces - Formation and Diffusion Energies.

PubMed

Chu, Haijian; Huang, Hanchen; Wang, Jian

2017-07-12

The formation and diffusion energies of atomic clusters on Mg surfaces determine the surface roughness and formation of faulted structure, which in turn affect the mechanical deformation of Mg. This paper reports first principles density function theory (DFT) based quantum mechanics calculation results of atomic clustering on the low energy surfaces {0001} and [Formula: see text]. In parallel, molecular statics calculations serve to test the validity of two interatomic potentials and to extend the scope of the DFT studies. On a {0001} surface, a compact cluster consisting of few than three atoms energetically prefers a face-centered-cubic stacking, to serve as a nucleus of stacking fault. On a [Formula: see text], clusters of any size always prefer hexagonal-close-packed stacking. Adatom diffusion on surface [Formula: see text] is high anisotropic while isotropic on surface (0001). Three-dimensional Ehrlich-Schwoebel barriers converge as the step height is three atomic layers or thicker. Adatom diffusion along steps is via hopping mechanism, and that down steps is via exchange mechanism.

Seal Formation Mechanism Beneath Animal Waste Holding Ponds

NASA Astrophysics Data System (ADS)

Cihan, A.; Tyner, J. S.; Wright, W. C.

2005-12-01

Infiltration of animal waste from holding ponds can cause contamination of groundwater. Typically, the initial flux from a pond decreases rapidly as a seal of animal waste particulates is deposited at the base of the pond. The purpose of this study was to investigate the mechanism of the seal formation. Twenty-four soil columns (10-cm diameter by 43-cm long) were hand-packed with sand, silty loam or clay soils. A 2.3 m column of dairy or swine waste was applied to the top of the each column. The leakage rate from each column was measured with respect to time to analyze the effect of seal formation on different soil textures and animal waste types. We tested our hypothesis that seal growth and the subsequent decrease of leachate production adheres to a filter cake growth model. Said model predicts that the cumulative leakage rate is proportional to the square root of time and to the square root of the height of the waste.

Wind-Driven Formation of Ice Bridges in Straits.

PubMed

Rallabandi, Bhargav; Zheng, Zhong; Winton, Michael; Stone, Howard A

2017-03-24

Ice bridges are static structures composed of tightly packed sea ice that can form during the course of its flow through a narrow strait. Despite their important role in local ecology and climate, the formation and breakup of ice bridges is not well understood and has proved difficult to predict. Using long-wave approximations and a continuum description of sea ice dynamics, we develop a one-dimensional theory for the wind-driven formation of ice bridges in narrow straits, which is verified against direct numerical simulations. We show that for a given wind stress and minimum and maximum channel widths, a steady-state ice bridge can only form beyond a critical value of the thickness and the compactness of the ice field. The theory also makes quantitative predictions for ice fluxes, which are particularly useful to estimate the ice export associated with the breakup of ice bridges. We note that similar ideas are applicable to dense granular flows in confined geometries.

Single-species microbial biofilm screening for industrial applications.

PubMed

Li, Xuan Zhong; Hauer, Bernhard; Rosche, Bettina

2007-10-01

While natural microbial biofilms often consist of multiple species, single-species biofilms are of great interest to biotechnology. The current study evaluates biofilm formation for common industrial and laboratory microorganisms. A total of 68 species of biosafety level one bacteria and yeasts from over 40 different genera and five phyla were screened by growing them in microtiter plates and estimating attached biomass by crystal violet staining. Most organisms showed biofilm formation on surfaces of polystyrene within 24 h. By changing a few simple conditions such as substratum characteristics, inoculum and nutrient availability, 66 strains (97%) demonstrated biofilm formation under at least one of the experimental conditions and over half of these strains were classified as strong biofilm formers, potentially suitable as catalysts in biofilm applications. Many non-motile bacteria were also strong biofilm formers. Biofilm morphologies were visualized for selected strains. A model organism, Zymomonas mobilis, easily established itself as a biofilm on various reactor packing materials, including stainless steel.

Kinetic Monte Carlo simulation of nanoparticle film formation via nanocolloid drying

NASA Astrophysics Data System (ADS)

Kameya, Yuki

2017-06-01

A kinetic Monte Carlo simulation of nanoparticle film formation via nanocolloid drying is presented. The proposed two-dimensional model addresses the dynamics of nanoparticles in the vertical plane of a drying nanocolloid film. The gas-liquid interface movement due to solvent evaporation was controlled by a time-dependent chemical potential, and the resultant particle dynamics including Brownian diffusion and aggregate growth were calculated. Simulations were performed at various Peclet numbers defined based on the rate ratio of solvent evaporation and nanoparticle diffusion. At high Peclet numbers, nanoparticles accumulated at the top layer of the liquid film and eventually formed a skin layer, causing the formation of a particulate film with a densely packed structure. At low Peclet numbers, enhanced particle diffusion led to significant particle aggregation in the bulk colloid, and the resulting film structure became highly porous. The simulated results showed some typical characteristics of a drying nanocolloid that had been reported experimentally. Finally, the potential of the model as well as the remaining challenges are discussed.

21 CFR 880.5760 - Chemical cold pack snakebite kit.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment of...

21 CFR 880.5760 - Chemical cold pack snakebite kit.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment of...

21 CFR 880.5760 - Chemical cold pack snakebite kit.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment of...

21 CFR 880.5760 - Chemical cold pack snakebite kit.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment of...

21 CFR 880.5760 - Chemical cold pack snakebite kit.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Chemical cold pack snakebite kit. 880.5760 Section... Therapeutic Devices § 880.5760 Chemical cold pack snakebite kit. (a) Identification. A chemical cold pack snakebit kit is a device consisting of a chemical cold pack and tourniquet used for first-aid treatment of...

49 CFR 173.127 - Class 5, Division 5.1-Definition and assignment of packing groups.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Packing Group II, any material which exhibits a mean pressure rise time less than or equal to the pressure... Packing Group I are not met. (iii) Packing Group III, any material which exhibits a mean pressure rise... packing groups. 173.127 Section 173.127 Transportation Other Regulations Relating to Transportation...

49 CFR 173.127 - Class 5, Division 5.1-Definition and assignment of packing groups.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Packing Group II, any material which exhibits a mean pressure rise time less than or equal to the pressure... Packing Group I are not met. (iii) Packing Group III, any material which exhibits a mean pressure rise... packing groups. 173.127 Section 173.127 Transportation Other Regulations Relating to Transportation...

On the kinetics of the pack - Aluminization process

NASA Technical Reports Server (NTRS)

Sivakumar, R.; Seigle, L. L.

1976-01-01

An investigation has been made of the aluminization of unalloyed Ni in fluoride-activated packs of varying Al activity. In packs of low Al activity, in which the ratio of Al to Ni was less than 50 at. pct, the specimen surface quickly came to equilibrium with the pack and remained close to equilibrium for the duration of normal coating runs. In these packs the kinetics of aluminization was controlled by diffusion in the solid. In packs of higher Al activity the surface of the specimen did not come to equilibrium with the pack and the kinetics of the process was governed by a combination of solid and gas diffusion rates. Under most conditions however, the surface composition was time-invariant and a steady-state appeared to exist at the pack-coating interface. By combining Levine and Caves' model for gaseous diffusion in pure-Al packs with calculations of solid diffusion rates some success has been achieved in explaining the results.

Nonuniversality of density and disorder in jammed sphere packings

NASA Astrophysics Data System (ADS)

Jiao, Yang; Stillinger, Frank H.; Torquato, Salvatore

2011-01-01

We show for the first time that collectively jammed disordered packings of three-dimensional monodisperse frictionless hard spheres can be produced and tuned using a novel numerical protocol with packing density ϕ as low as 0.6. This is well below the value of 0.64 associated with the maximally random jammed state and entirely unrelated to the ill-defined "random loose packing" state density. Specifically, collectively jammed packings are generated with a very narrow distribution centered at any density ϕ over a wide density range ϕ ɛ(0.6,0.740 48…) with variable disorder. Our results support the view that there is no universal jamming point that is distinguishable based on the packing density and frequency of occurrence. Our jammed packings are mapped onto a density-order-metric plane, which provides a broader characterization of packings than density alone. Other packing characteristics, such as the pair correlation function, average contact number, and fraction of rattlers are quantified and discussed.

Effects of different shear rates on the attachment and detachment of platelet thrombi.

PubMed

Shi, Xiaofeng; Yang, Jichun; Huang, Jiansong; Long, Zhangbiao; Ruan, Zheng; Xiao, Bing; Xi, Xiaodong

2016-03-01

Thrombosis and hemostasis take place in flowing blood, which generates shear forces. The effect of different shear rates, particularly pathological forces, on platelet thrombus formation remains to be fully elucidated. The present study observed the morphological characteristics and hierarchical structure of thrombi on the collagen surface at a wide range of wall shear rates (WSRs) and examined the underlying mechanisms. Calcein AM‑labeled whole blood was perfused over a collagen‑coated surface at different shear rates set by a Bioflux 200 microfluidic device and the thrombi formed were assessed for area coverage, the height and the hierarchical structure defined by the extent of platelet activation and packing density. The factors that affect thrombus formation were also investigated. Platelet thrombus formation varied under different WSRs, for example, dispersed platelet adhesion mixed with erythrocytes was observed at 125‑250 s(‑1), extensive and thin platelet thrombi were observed at 500‑1,500 s(‑1), and sporadic, thick thrombi were observed at pathological WSRs of 2,500‑5,000 s(‑1), which showed a tendency to be shed. With increasing WSRs, the height of the thrombi showed an increasing linear trend, whereas the total fluorescence intensity and area of the thrombi exhibited a parabolic curve‑like change, with a turning point at a WSR of 2,500 s(‑1). The number of thrombi, the average fluorescence intensity and the area per thrombus showed similar trends, with an initial upwards incline followed by a decline. The thrombi formed at higher WSRs had a thicker shell, which led to a more densely packed core. Platelet thrombus formation under shear‑flow was regulated by the adhesive strength, which was mediated by receptor‑ligand interaction, the platelet deposition induced by shear rates and the detachment by the dynamic force of flow. This resulted in a balance between thrombus attachment, including adhesion and aggregation, and detachment. Collectively, compared with physiological low WSRs, pathological high WSRs caused thicker and more easily shed thrombi with more condensed cores, which was regulated by an attachment‑detachment balance. These results provide novel insights into the properties of thrombus formation on collagen at different WSRs, and offers possible explanations for certain clinical physiopathological phenomena, including physical hemostasis and pathological thrombosis.

Prostatic fossa gauze-packing in the prevention of blood clot obstruction of the bladder after transvesical prostatectomy.

PubMed

Umunna, J I

2010-01-01

Clot obstruction often complicates transvesical prostatectomy. Any measure that prevents this will be a great relief to both surgeon and patient. To demonstrate that packing the prostatic fossa with roller gauze bandage after transvesical prostatectomy can prevent post-operative clot blockage of bladder drainage . Charts of all patients who had transvesical prostatectomy at Jasman Hospital Udo by me from 1988 to 1997 were sorted into two groups , Group A, not packed and Group B, packed. Information sought included patient's age, type of prostatectomy performed, whether the prostatic fossa was packed or not , average duration of catheter drainage, and complications. There were 68 patients who had no fossa packing and 72 in Group B with fossa packing. The age range of the two groups A and B were respective 45-85 year-old and 50-83 years. In both groups the highest number of patients was in the 60 t0 79 age bracket (48 in group A , 70%, and 56 in group B (78%). Bladder blockage occurred in 32(47%) patients without packing and none (0%) in group B with packing. Average duration of bladder drainage was 14 days in each group. There was no persisting vesico-cutaneous fistula. Temporary urinary incontinence occurred in three (3%) patients who had no packing and in five (7%) with packing. Gauze-packing of the prostatic fossa during transvesical prostatectomy can prevent bladder obstruction from clot retention without undue complications.

Psychrotrophic Clostridium spp. associated with 'blown pack' spoilage of chilled vacuum-packed red meats and dog rolls in gas-impermeable plastic casings.

PubMed

Broda, D M; DeLacy, K M; Bell, R G; Braggins, T J; Cook, R L

1996-04-01

'Blown pack' spoilage of vacuum-packed chilled beef, lamb and venison, and of a cooked meat product, chilled dog rolls packed in an oxygen-impermeable plastic casing, was characterised by sensory, chemical and microbiological analysis. Investigation of the probable causative agents led to the isolation of eight strains of psychrotrophic clostridia. Three strains have been provisionally identified as C. difficile, C. beijerinckii and C. lituseburense; the other five remain unidentified. In inoculation studies only one isolate produced significant amount of gas on meat, causing pack 'blowing'. It is, therefore, possible that 'blown pack' spoilage involves a synergism with one or more other organisms.

Simulation of abuse tolerance of lithium-ion battery packs

NASA Astrophysics Data System (ADS)

Spotnitz, Robert M.; Weaver, James; Yeduvaka, Gowri; Doughty, D. H.; Roth, E. P.

A simple approach for using accelerating rate calorimetry data to simulate the thermal abuse resistance of battery packs is described. The thermal abuse tolerance of battery packs is estimated based on the exothermic behavior of a single cell and an energy balance than accounts for radiative, conductive, and convective heat transfer modes of the pack. For the specific example of a notebook computer pack containing eight 18650-size cells, the effects of cell position, heat of reaction, and heat-transfer coefficient are explored. Thermal runaway of the pack is more likely to be induced by thermal runaway of a single cell when that cell is in good contact with other cells and is close to the pack wall.

Refreshable Braille displays using EAP actuators

NASA Astrophysics Data System (ADS)

Bar-Cohen, Yoseph

2010-04-01

Refreshable Braille can help visually impaired persons benefit from the growing advances in computer technology. The development of such displays in a full screen form is a great challenge due to the need to pack many actuators in small area without interferences. In recent years, various displays using actuators such as piezoelectric stacks have become available in commercial form but most of them are limited to one line Braille code. Researchers in the field of electroactive polymers (EAP) investigated methods of using these materials to form full screen displays. This manuscript reviews the state of the art of producing refreshable Braille displays using EAP-based actuators.

Refreshable Braille Displays Using EAP Actuators

NASA Technical Reports Server (NTRS)

Bar-Cohen, Yoseph

2010-01-01

Refreshable Braille can help visually impaired persons benefit from the growing advances in computer technology. The development of such displays in a full screen form is a great challenge due to the need to pack many actuators in small area without interferences. In recent years, various displays using actuators such as piezoelectric stacks have become available in commercial form but most of them are limited to one line Braille code. Researchers in the field of electroactive polymers (EAP) investigated methods of using these materials to form full screen displays. This manuscript reviews the state of the art of producing refreshable Braille displays using EAP-based actuators..

Paediatric oncology information pack for general practitioners

PubMed Central

James, J A; Harris, D J; Mott, M G; Oakhill, A

1988-01-01

An information pack covering important aspects of paediatric oncology has been developed for general practitioners. Sixty general practitioners who received the information pack found that it helped them in managing children with neoplastic disease and their families. The pack has also improved communications between the oncology unit and general practitioners. Similar packs could be produced by paediatricians working in other specialties. PMID:3122972

Simulation of lithium ion battery replacement in a battery pack for application in electric vehicles

NASA Astrophysics Data System (ADS)

Mathew, M.; Kong, Q. H.; McGrory, J.; Fowler, M.

2017-05-01

The design and optimization of the battery pack in an electric vehicle (EV) is essential for continued integration of EVs into the global market. Reconfigurable battery packs are of significant interest lately as they allow for damaged cells to be removed from the circuit, limiting their impact on the entire pack. This paper provides a simulation framework that models a battery pack and examines the effect of replacing damaged cells with new ones. The cells within the battery pack vary stochastically and the performance of the entire pack is evaluated under different conditions. The results show that by changing out cells in the battery pack, the state of health of the pack can be consistently maintained above a certain threshold value selected by the user. In situations where the cells are checked for replacement at discrete intervals, referred to as maintenance event intervals, it is found that the length of the interval is dependent on the mean time to failure of the individual cells. The simulation framework as well as the results from this paper can be utilized to better optimize lithium ion battery pack design in EVs and make long term deployment of EVs more economically feasible.

Improvising a Posterior Nasal Pack with Equipment in a Basic First Aid Kit.

PubMed

Royer, Allison K; Royer, Mark C

2016-09-01

Posterior epistaxis is a serious condition that can be difficult to treat in a wilderness setting. The initial standard of care involves packing the affected nostril with a 7 to 9 cm nasal pack to tamponade the bleed. These packs are often unavailable outside of the emergency or operating room. This study set out to determine whether a posterior nasal pack could be constructed from the supplies present in a basic first aid kit in order to control massive nasal hemorrhage in a wilderness setting. A basic first aid kit was utilized to construct a posterior nasal pack that was inserted into an anatomical model and visibly compared with the Rapid Rhino (Posterior, 7.5 cm; Smith & Nephew, Austin, TX) nasal packing. The shape, size, and anatomical areas of compression (ie, into nasopharynx and posterior aspect of inferior turbinate) of this pack was similar to the commercially available posterior nasal pack. Placement in an anatomical model appears to provide similar compression as the commercially available posterior pack. This technique may provide short-term hemorrhage control in cases of serious posterior nasal hemorrhage where standard treatment options are not available. Copyright © 2016 Wilderness Medical Society. Published by Elsevier Inc. All rights reserved.

Promotions on Newport and Marlboro Cigarette Packages: A National Study.

PubMed

Lee, Joseph G L; Richardson, Amanda; Golden, Shelley D; Ribisl, Kurt M

2017-10-01

While cigarette pack designs are part of integrated marketing efforts, it is unclear the degree to which packs are used to advertise promotions and whether the tobacco retailers' neighborhood characteristics influence the likelihood and type of pack-based promotion in the United States. Between June and October 2012, data collectors purchased packs of either Marlboro Red (n = 1090) or Newport Green (n = 1057) cigarettes at 2147 stores that were part of a national sample of tobacco retailers in the contiguous US. Coders rated packs for the presence of an exterior and interior pack promotion, placement of exterior promotion (eg, front, back), presentation of exterior promotion (eg, onsert, tear strip), and nature of the promotion (eg, contest/give/away). Using Census tract data, we examined the association of pack promotions with tobacco retailers' neighborhood demographic characteristics. Marlboro packs were approximately twice as likely to have promotions as Newport packs (31.7% vs. 14.7%). Fewer Marlboro packs (14.6%) and no Newport packs had interior promotions. The majority of exterior promotions were for contests (>80% for both brands), while almost all interior Marlboro promotions (97.5%) were for a discounted price. There were few differences in presence or type of promotion by tobacco retailers' neighborhood characteristics. Exterior packs promotions, in particular, were fairly common and may contribute to the allure of tobacco products. Use of promotions on the interior and exterior of cigarette packs are a mechanism that the tobacco industry uses to sell its products and should be continually assessed for their influence on consumer behavior. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

A study on the consumer's perception of front-of-pack nutrition labeling

PubMed Central

Kim, Woo Kyoung

2009-01-01

The goal of this research is to investigate the present situation for front of pack labeling in Korea and the perception of consumers for the new system of labeling, front of pack labeling, based on the consumer survey. We investigated the number of processed foods with front of pack labeling in one retailer in Youngin-si. And we also surveyed 1,019 participants nationwide whose ages were from 20 to 49; the knowledge of nutrition labeling, the knowledge of 'front of pack labeling', and the opinion about the labeling system. The data were analyzed using SAS statistics program. The results were as follows: 13.4% of processed foods had front of pack labeling, and 16.8% of the consumers always checked the nutrition labeling, while 32.7% of the consumers seldom checked it. In addition, 44.3% of the consumers think that 'front of pack labeling' is necessary, and 58.3% of the consumers think it is important to show the percentage of daily value as a way of 'front of pack labeling'. However, 32% of the consumer think the possibility of 'front of pack labeling' is slim. Meanwhile, 58.3% of the consumers think that it is important to have the color difference according to contents. The number of favorite nutrients in the front of pack was four or five. It seems that the recognition of current nutrition labeling has the influence on the willingness of using the future 'front of pack labeling'. Along with our study, the policy for 'front of pack labeling' has to be updated and improved constantly since 'front of pack labeling' helps consumer understand nutrition facts. PMID:20098583

5 Reasons to Pack Your Lunch

MedlinePlus

... Staying Safe Videos for Educators Search English Español 5 Reasons to Pack Your Lunch KidsHealth / For Teens / 5 Reasons to Pack Your Lunch Print 5 Reasons to Pack Your Lunch Most schools are ...

Random packing of regular polygons and star polygons on a flat two-dimensional surface.

PubMed

Cieśla, Michał; Barbasz, Jakub

2014-08-01

Random packing of unoriented regular polygons and star polygons on a two-dimensional flat continuous surface is studied numerically using random sequential adsorption algorithm. Obtained results are analyzed to determine the saturated random packing ratio as well as its density autocorrelation function. Additionally, the kinetics of packing growth and available surface function are measured. In general, stars give lower packing ratios than polygons, but when the number of vertexes is large enough, both shapes approach disks and, therefore, properties of their packing reproduce already known results for disks.

PCR detection of psychrophilic Clostridium spp. causing 'blown pack' spoilage of vacuum-packed chilled meats.

PubMed

Broda, D M; Boerema, J A; Bell, R G

2003-01-01

To develop a practical molecular procedure that directly, without isolation, and specifically detects the presence of clostridia which cause 'blown pack' spoilage of vacuum-packed meat. Primer sets and PCR amplification procedures were developed that detect the presence of 16S rDNA gene and/or 16S-23S rDNA internal transcribed spacer fragments of 'blown pack' causing clostridia in meat. The specificity of the developed procedures was evaluated with DNA obtained from close phylogenetic neighbours of 'blown pack' causing clostridia, food clostridia and common meat spoilage microorganisms. The sensitivity of detection was assessed in non-enriched and low-temperature-enriched beef mince inoculated with serially diluted pure cultures of Clostridium estertheticum DSMZ 8809T and Cl. gasigenes DB1AT. The efficacy of detection procedures was evaluated for naturally contaminated vacuum-packed meat samples. Three primer sets, 16SE, 16SDB and EISR, produced amplicons of the expected size with DNA templates from target clostridia, but failed to yield PCR products with DNAs from any other microorganisms tested. With 16SE and 16SDB primers, minimum levels of detection were 104 CFU g(-1) for non-enriched, and 102 CFU g(-1) for enriched meat samples. Based on the established specificity of these primers, as well as DNA sequencing of amplicons, Cl. gasigenes was confirmed as the causative agent of 'blown pack' spoilage in two packs, and Cl. estertheticum as the causative agent in the third. The developed method can be used for rapid detection of 'blown pack' causing clostridia in commercial blown packs, or following low temperature enrichment, for detection of these microorganisms in meat containing as few as 100 clostridial cells per gram. The paper reports practical procedures that can be used for rapid confirmation of the causative agents of clostridial 'blown pack' spoilage in commercial spoiled packs, or for detection of psychrophilic clostridia in epidemiological trace back of 'blown pack' spoilage incidents in meat processing plants.

Adolescents' perceptions of cigarette brand image: does plain packaging make a difference?

PubMed

Germain, Daniella; Wakefield, Melanie A; Durkin, Sarah J

2010-04-01

To examine the effect of plain packaging on adolescents' perceptions of cigarette packs, attributes of smokers, and expectations of cigarette taste, and to identify the effect of increasing the size of pictorial health warnings on appraisal of plain packs. We used a 5 (degree of plain packaging and graphic health warning)x 3 (brand type) between-subjects experimental design, using a Web-based methodology to expose adolescents to one randomly selected cigarette pack, during which respondents completed ratings. When brand elements such as color, branded fonts, and imagery were progressively removed from cigarette packs, adolescents perceived packs to be less appealing, rated attributes of a typical smoker of the pack less positively, and had more negative expectations of cigarette taste. Pack appeal was reduced even further when the size of the pictorial health warning on the most plain pack was increased from 30% to 80% of the pack face, with this effect apparent among susceptible nonsmokers, experimenters, and established smokers. Removing as much brand information from cigarette packs as possible is likely to reduce positive cigarette brand image associations among adolescents. By additionally increasing the size of pictorial health warnings, positive pack perceptions of those who are at greater risk of becoming regular addicted adult smokers are most likely to be reduced. Copyright 2010 Society for Adolescent Medicine. Published by Elsevier Inc. All rights reserved.

DEM simulation of dendritic grain random packing: application to metal alloy solidification

NASA Astrophysics Data System (ADS)

Olmedilla, Antonio; Založnik, Miha; Combeau, Hervé

2017-06-01

The random packing of equiaxed dendritic grains in metal-alloy solidification is numerically simulated and validated via an experimental model. This phenomenon is characterized by a driving force which is induced by the solid-liquid density difference. Thereby, the solid dendritic grains, nucleated in the melt, sediment and pack with a relatively low inertia-to-dissipation ratio, which is the so-called Stokes number. The characteristics of the particle packed porous structure such as solid packing fraction affect the final solidified product. A multi-sphere clumping Discrete Element Method (DEM) approach is employed to predict the solid packing fraction as function of the grain geometry under the solidification conditions. Five different monodisperse noncohesive frictionless particle collections are numerically packed by means of a vertical acceleration: a) three dendritic morphologies; b) spheres and c) one ellipsoidal geometry. In order to validate our numerical results with solidification conditions, the sedimentation and packing of two monodisperse collections (spherical and dendritic) is experimentally carried out in a viscous quiescent medium. The hydrodynamic similarity is respected between the actual phenomenon and the experimental model, that is a low Stokes number, o(10-3). In this way, the experimental average solid packing fraction is employed to validate the numerical model. Eventually, the average packing fraction is found to highly depend on the equiaxed dendritic grain sphericity, with looser packings for lower sphericity.

Structural characterization of the packings of granular regular polygons.

PubMed

Wang, Chuncheng; Dong, Kejun; Yu, Aibing

2015-12-01

By using a recently developed method for discrete modeling of nonspherical particles, we simulate the random packings of granular regular polygons with three to 11 edges under gravity. The effects of shape and friction on the packing structures are investigated by various structural parameters, including packing fraction, the radial distribution function, coordination number, Voronoi tessellation, and bond-orientational order. We find that packing fraction is generally higher for geometrically nonfrustrated regular polygons, and can be increased by the increase of edge number and decrease of friction. The changes of packing fraction are linked with those of the microstructures, such as the variations of the translational and orientational orders and local configurations. In particular, the free areas of Voronoi tessellations (which are related to local packing fractions) can be described by log-normal distributions for all polygons. The quantitative analyses establish a clearer picture for the packings of regular polygons.

cellPACK: A Virtual Mesoscope to Model and Visualize Structural Systems Biology

PubMed Central

Johnson, Graham T.; Autin, Ludovic; Al-Alusi, Mostafa; Goodsell, David S.; Sanner, Michel F.; Olson, Arthur J.

2014-01-01

cellPACK assembles computational models of the biological mesoscale, an intermediate scale (10−7–10−8m) between molecular and cellular biology. cellPACK’s modular architecture unites existing and novel packing algorithms to generate, visualize and analyze comprehensive 3D models of complex biological environments that integrate data from multiple experimental systems biology and structural biology sources. cellPACK is currently available as open source code, with tools for validation of models and with recipes and models for five biological systems: blood plasma, cytoplasm, synaptic vesicles, HIV and a mycoplasma cell. We have applied cellPACK to model distributions of HIV envelope protein to test several hypotheses for consistency with experimental observations. Biologists, educators, and outreach specialists can interact with cellPACK models, develop new recipes and perform packing experiments through scripting and graphical user interfaces at http://cellPACK.org. PMID:25437435

Nutritional contents of lunch packs of primary school children in nnewi, Nigeria.

PubMed

Ugochukwu, Ef; Onubogu, Cu; Edokwe, Es; Okeke, Kn

2014-07-01

Lunch packs play a significant role in the nutritional status and academic performance of school children. Available data show a high prevalence of malnutrition among school-age children. The aim of this study is to document the nutritional contents of lunch packs of primary school children in Nnewi, Anambra state, Nigeria. A cross-sectional study was conducted among 1018 primary 1-6 pupils selected by stratified systematic random sampling from six primary schools, two each of private, - mission, - and government (public) - owned schools in Nnewi metropolis with the aid of the semi-structured questionnaire. Lunch packs of the pupils were examined. Majority of the pupils (77.8% [792/1018]) had lunch packs although about half of pupils in public schools had no lunch pack. Only 12.4% (98/792) and 19.2% (152/792) of pupils with lunch packs had balanced meals and fruits/vegetables in their lunch packs, respectively. The odds of not coming to school with packed lunch was about 13 and 12 times higher for mothers with no formal education or only primary education, respectively, compared with those with tertiary education. Type of school had a strong influence on possession and contents of lunch pack (χ(2) = 2.88, P < 0.001, phi coefficient = 0.72). Pupils in private (97.5% [198/203]) and mission (94.4% [388/411]) schools were more likely to have a lunch pack compared with public schools (51.0% [206/404]). However, pupils in private schools were most likely to have a balanced meal (32.5% [66/203] vs. 5.8% [24/411] in mission and 2.0% [8/404] in public schools) and fruits/vegetables (48.3% [98/203] vs. 10.2% [42/411] in mission and 3.0% [12/404] in public schools) in their lunch packs. Mothers' educational status and parents' occupation were significantly associated with lunch pack contents. Majority of the lunch packs of primary school pupils contain poor quality food especially in public schools. Mother's educational status and parent's occupation are important determinants of the nutritional contents of lunch packs.

LOW-ENGINE-FRICTION TECHNOLOGY FOR ADVANCED NATURAL-GAS RECIPROCATING ENGINES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Victor W. Wong; Tian Tian; Grant Smedley

2004-09-30

This program aims at improving the efficiency of advanced natural-gas reciprocating engines (ANGRE) by reducing piston/ring assembly friction without major adverse effects on engine performance, such as increased oil consumption and emissions. An iterative process of simulation, experimentation and analysis, are being followed towards achieving the goal of demonstrating a complete optimized low-friction engine system. To date, a detailed set of piston/ring dynamic and friction models have been developed and applied that illustrated the fundamental relationships between design parameters and friction losses. Various low-friction strategies and ring-design concepts have been explored, and engine experiments have been done on a full-scalemore » Waukesha VGF F18 in-line 6 cylinder power generation engine rated at 370 kW at 1800 rpm. Current accomplishments include designing and testing ring-packs using a subtle top-compression-ring profile (skewed barrel design), lowering the tension of the oil-control ring, employing a negative twist to the scraper ring to control oil consumption. Initial test data indicate that piston ring-pack friction was reduced by 35% by lowering the oil-control ring tension alone, which corresponds to a 1.5% improvement in fuel efficiency. Although small in magnitude, this improvement represents a first step towards anticipated aggregate improvements from other strategies. Other ring-pack design strategies to lower friction have been identified, including reduced axial distance between the top two rings, tilted top-ring groove. Some of these configurations have been tested and some await further evaluation. Colorado State University performed the tests and Waukesha Engine Dresser, Inc. provided technical support. Key elements of the continuing work include optimizing the engine piston design, application of surface and material developments in conjunction with improved lubricant properties, system modeling and analysis, and continued technology demonstration in an actual full-sized reciprocating natural-gas engine.« less

Face-specific Replacement of Calcite by Amorphous Silica Nanoparticles

NASA Astrophysics Data System (ADS)

Liesegang, M.; Milke, R.; Neusser, G.; Mizaikoff, B.

2016-12-01

Amorphous silica, composed of nanoscale spheres, is an important biomineral, alteration product of silicate rocks on the Earth's surface, and precursor material for stable silicate minerals. Despite constant progress in silica sphere synthesis, fundamental knowledge of natural silica particle interaction and ordering processes leading to colloidal crystals is absent so far. To understand the formation pathways of silica spheres in a geologic environment, we investigated silicified Cretaceous mollusk shell pseudomorphs from Coober Pedy (South Australia) using focused ion beam (FIB)-SEM tomography, petrographic microscopy, µ-XRD, and EMPA. The shells consist of replaced calcite crystals (<2 mm) composed of ordered arrays of uniform, close-packed silica spheres 300 ± 10 nm in size. Concentric layered spheres composed of 40 nm-sized subparticles provide evidence that, at least in the final stage, particle aggregation was the major sphere growth mechanism. Silica sphere arrays in periodically changing orientations perfectly replicate polysynthetic twinning planes of calcite. FIB-SEM tomography shows that cubic closed-packed sphere arrangements preserve the twin lamellae, while the twin plane consists of a submicrometer layer of randomly ordered spheres and vacancies. To transfer crystallographic information from parent to product, the advancement of synchronized dissolution and precipitation fronts along lattice planes is essential. We assume that the volume-preserving replacement process proceeds via a face-specific dissolution-precipitation mechanism with intermediate subparticle aggregation and subsequent layer-by-layer deposition of spheres along a planar surface. Porosity created during the replacement reaction allows permanent fluid access to the propagating reaction interface. Fluid pH and ionic strength remain constant throughout the replacement process, permitting continuous silica nanoparticle formation and diffusion-limited colloid aggregation. Our study provides a natural example of the transformation of an atomic crystal to an amorphous, mesoscale ordered material; thus, links the research fields of natural colloidal crystal formation, carbonate-silica replacement, and crystallization by oriented particle aggregation (CPA).

Synthesis, physical properties and self-assembly behavior of azole-fused pyrene derivatives

NASA Astrophysics Data System (ADS)

Xiao, Jinchong; Xiao, Xuyu; Zhao, Yanlei; Wu, Bo; Liu, Zhenying; Zhang, Xuemin; Wang, Sujuan; Zhao, Xiaohui; Liu, Lei; Jiang, Li

2013-05-01

A novel selenadiazole-fused pyrene derivative PySe was successfully synthesized and characterized. Its single structure is almost planar and adopts a sandwich-herringbone packing model. The self-assembly behaviors based on compound PySe and its analogue thiadiazole-fused pyrene derivative PyS were studied in detail and the as-formed nanostructures were fully characterized by means of UV-vis absorption, emission spectra, X-ray diffraction, field emission SEM and TEM. We attribute the bathochromic shift absorption and emission spectra of PyS and PySe in aqueous solution to the formation of J-type aggregation. In addition, our investigation demonstrated that the shape and size of the as-prepared nanostructures could be tuned by different chalcogen analogues and the volume ratio of water to organic solvent.A novel selenadiazole-fused pyrene derivative PySe was successfully synthesized and characterized. Its single structure is almost planar and adopts a sandwich-herringbone packing model. The self-assembly behaviors based on compound PySe and its analogue thiadiazole-fused pyrene derivative PyS were studied in detail and the as-formed nanostructures were fully characterized by means of UV-vis absorption, emission spectra, X-ray diffraction, field emission SEM and TEM. We attribute the bathochromic shift absorption and emission spectra of PyS and PySe in aqueous solution to the formation of J-type aggregation. In addition, our investigation demonstrated that the shape and size of the as-prepared nanostructures could be tuned by different chalcogen analogues and the volume ratio of water to organic solvent. Electronic supplementary information (ESI) available: TGA analysis, spectra characterization data for compound 1, 2, 3 and X-ray crystallographic data for compound PySe (2, CIF). CCDC 917821. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3nr00523b

Consumer perceptions of cigarette pack design in France: a comparison of regular, limited edition and plain packaging.

PubMed

Gallopel-Morvan, Karine; Moodie, Crawford; Hammond, David; Eker, Figen; Beguinot, Emmanuelle; Martinet, Yves

2012-09-01

In the face of comprehensive bans on the marketing of tobacco products, packaging has become an increasingly important promotional tool for the tobacco industry. A ban on the use of branding on tobacco packaging, known as 'plain' packaging, has emerged as a promising regulatory strategy. The current study sought to examine perceptions of cigarette packaging among adults in France. Adult smokers and non-smokers (N=836) were surveyed using computer-assisted personal interviewing to assess perceptions of pack design by comparing 'regular' branded packs and 'limited edition' packs (with novel designs or innovations) with 'plain' versions of these packs with all branding, including colour, removed. Plain packs (PP) were less likely than regular packs, and particularly limited edition packs, to be considered attractive, attention grabbing and likely to motivate youth purchase. PPs were also rated as the most effective in convincing non-smokers not to start and smokers to reduce consumption and quit. Logistic regression showed that smokers motivated to quit, in comparison to smokers not motivated to quit, were significantly more likely to consider the PPs as the packs most likely to motivate cessation. Novel cigarette packaging, in the form of limited edition packs, had the highest ratings of consumer appeal, ahead of regular branded packs and also PPs. Interestingly, PPs were perceived to be the packs most likely to promote cessation among those adults with quitting intentions. Plain packaging, therefore, may be a means of helping existing adult smokers motivated to quit to do so.

How changes in top water bother big turning packs of up-going wet air

NASA Astrophysics Data System (ADS)

Wood, K.

2017-12-01

Big turning packs of up-going wet air form near areas of warm water at the top of big bodies of water. After these turning packs form, they usually get stronger if the top water stays warm. If the top water becomes less warm, the turning packs usually get less strong. Other things can change how strong a turning pack gets, like how wet the air around it is and if that air moves faster higher up than lower down. When these turning packs hit land, their rain and winds can hurt people and the stuff they own, especially if the turning pack is really strong. But it's hard to know how much stronger or less strong it will become before it hits land. Warm top water gives a turning pack of up-going wet air a lot of power, but cool top water doesn't, so we need to know how warm the top water is. Because I can't go into every turning pack myself, flying computers in outer space tell me what the top water is doing. I look at the top water near turning packs that get strong and see how it's different from the top water near those that get less strong. Top water that changes from warm to cool in a small area bothers a turning pack of up-going wet air, which then gets less strong. If we see these top water changes ahead of time, that might help us know what a turning pack will do before it gets close to land.

Menu-Driven Solver Of Linear-Programming Problems

NASA Technical Reports Server (NTRS)

Viterna, L. A.; Ferencz, D.

1992-01-01

Program assists inexperienced user in formulating linear-programming problems. A Linear Program Solver (ALPS) computer program is full-featured LP analysis program. Solves plain linear-programming problems as well as more-complicated mixed-integer and pure-integer programs. Also contains efficient technique for solution of purely binary linear-programming problems. Written entirely in IBM's APL2/PC software, Version 1.01. Packed program contains licensed material, property of IBM (copyright 1988, all rights reserved).

Cluster and constraint analysis in tetrahedron packings

NASA Astrophysics Data System (ADS)

Jin, Weiwei; Lu, Peng; Liu, Lufeng; Li, Shuixiang

2015-04-01

The disordered packings of tetrahedra often show no obvious macroscopic orientational or positional order for a wide range of packing densities, and it has been found that the local order in particle clusters is the main order form of tetrahedron packings. Therefore, a cluster analysis is carried out to investigate the local structures and properties of tetrahedron packings in this work. We obtain a cluster distribution of differently sized clusters, and peaks are observed at two special clusters, i.e., dimer and wagon wheel. We then calculate the amounts of dimers and wagon wheels, which are observed to have linear or approximate linear correlations with packing density. Following our previous work, the amount of particles participating in dimers is used as an order metric to evaluate the order degree of the hierarchical packing structure of tetrahedra, and an order map is consequently depicted. Furthermore, a constraint analysis is performed to determine the isostatic or hyperstatic region in the order map. We employ a Monte Carlo algorithm to test jamming and then suggest a new maximally random jammed packing of hard tetrahedra from the order map with a packing density of 0.6337.

Comparative elimination of dimethyl disulfide by maifanite and ceramic-packed biotrickling filters and their response to microbial community.

PubMed

Chen, Xuequan; Liang, Zhishu; An, Taicheng; Li, Guiying

2016-02-01

Unpleasant odor emissions have traditionally occupied an important role in environmental concern. In this paper, twin biotrickling filters (BTFs) packed with different packing materials, seeded with Bacillus cereus GIGAN2, were successfully constructed to purify gaseous dimethyl disulfide (DMDS). The maifanite-packed BTF showed superior biodegradation capability to the ceramic-packed counterpart in terms of removal efficiency and elimination capacity under similar conditions. At an empty bed residence time of 123 s, 100% of DMDS could be removed by maifanite-packed BTF when DMDS inlet concentration was below 0.41 g m(-3). To achieve same effect, the inlet concentration must be lower than 0.25 g m(-3) for ceramic-packed BTF. The bacterial communities analyses found higher relative abundance of GIGAN2 in the maifanite-packed BTF, suggesting that maifanite is more suitable for GIGAN2 immobilization and for subsequent DMDS removal. This work indicates maifanite is a promising packing material for real odorous gases purification. Copyright © 2015 Elsevier Ltd. All rights reserved.

Multi-scale structures and functional properties of starches from Indica hybrid, Japonica and waxy rice.

PubMed

Wang, Shujun; Li, Peiyan; Yu, Jinglin; Guo, Peng; Wang, Shuo

2017-09-01

The structural and functional properties of starches from three rice grains differing in amylose content (19.9, 13.4 and 0.8% for Japonica, Indica hybrid and waxy rice, respectively) were investigated using a range of characterization methods Indica hybrid starch (IHS) had the highest proportion of intermediate (DP 13-24) and long branch chains (DP≥37) and the lowest proportion of short branch chains (DP 6-12), whereas the opposite results were observed for Japonica starch (JS). The results for waxy rice starch (WS) were between those of IHS and JS. Rice starches showed a typical A-type X-ray diffraction pattern with the relative crystallinity ranging from 33.4% for JS to 39.4% for WS. Significant differences were observed in lamellar distance and short-range molecular order characterized by IR ratio of absorbances at 1047/1022cm -1 and full width of half maximum (FWHM) of the band at 480cm -1 . WS showed a higher swelling power and a lower close packing concentration at temperatures from 60 to 90°C. The lower peak viscosity of WS was attributed to the formation of less rigid swollen granules at a concentrated regime. WS showed a higher in vitro digestibility compared with IHS and JS. Copyright © 2017 Elsevier B.V. All rights reserved.

Experiments versus modeling of buoyant drying of porous media

NASA Astrophysics Data System (ADS)

Salin, D.; Yiotis, A.; Tajer, E.; Yortsos, Y. C.

2012-12-01

Experiments versus modeling of buoyant drying of porous media D. Salin and A.G. Yiotis, Laboratoire FAST, Univ Pierre & Marie Curie, Univ. Paris-Sud, CNRS, Orsay 91405, France and E.S. Tajer and Y.C. Yortsos, Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1450 A series of isothermal drying experiments in packed glass beads saturated with volatile hydrocarbons (hexane or pentane) are conducted. The transparent glass cells containing the packing allow for the visual monitoring of the phase distribution patterns below the surface, including the formation of liquid films, as the gaseous phase invades the pore space, and for the control of the thickness of the diffusive mass boundary layer over the packing. We demonstrate the existence of an early Constant Rate Period, CRP, that lasts as long as the films saturate the surface of the packing, and of a subsequent Falling Rate Period, FRP, that begins practically after the detachment of the film tips from the external surface. During the CRP, the process is controlled by diffusion within the stagnant gaseous phase in the upper part of the cells, yielding a Stefan tube problem solution. During the FRP, the process is controlled by diffusion within the packing, with a drying rate inversely proportional to the observed position of the film tips in the cell. The critical residual liquid saturation that marks the transition between these two regimes is found to be a function of the average bead size in our packs and the incline of the cells with respect to the flat vertical, with larger beads and angles closer to the vertical position leading to earlier film detachment times and higher critical saturations. We developed a model for the drying of porous media in the presence of gravity. It incorporated effects of corner film flow, internal and external mass transfer and the effect of gravity. Analytical results were derived when gravity opposes drying and hence leads to a stable percolation drying front. We are thus able to obtain results for the drying rates, the critical saturation and the extent of the film region with respect to the various dimensionless numbers that describe the process; the Bond (Bo)number, a film-based Capillary (Ca) number and the dimensionless extent of the mass boundary layer (Sh). The experimental results agree very well with the theory, provided that the latter is generalized to account for the effects of corner roundness in the film region which were neglected in our analytical approach. The agreement is achieved for a specific value of the roundness of the films, which is found to be constant and equal to 0.2 for various conditions, and verify the theoretical dependence on Ca, Bo and Sh numbers.

A global analysis of adaptive evolution of operons in cyanobacteria.

PubMed

Memon, Danish; Singh, Abhay K; Pakrasi, Himadri B; Wangikar, Pramod P

2013-02-01

Operons are an important feature of prokaryotic genomes. Evolution of operons is hypothesized to be adaptive and has contributed significantly towards coordinated optimization of functions. Two conflicting theories, based on (i) in situ formation to achieve co-regulation and (ii) horizontal gene transfer of functionally linked gene clusters, are generally considered to explain why and how operons have evolved. Furthermore, effects of operon evolution on genomic traits such as intergenic spacing, operon size and co-regulation are relatively less explored. Based on the conservation level in a set of diverse prokaryotes, we categorize the operonic gene pair associations and in turn the operons as ancient and recently formed. This allowed us to perform a detailed analysis of operonic structure in cyanobacteria, a morphologically and physiologically diverse group of photoautotrophs. Clustering based on operon conservation showed significant similarity with the 16S rRNA-based phylogeny, which groups the cyanobacterial strains into three clades. Clade C, dominated by strains that are believed to have undergone genome reduction, shows a larger fraction of operonic genes that are tightly packed in larger sized operons. Ancient operons are in general larger, more tightly packed, better optimized for co-regulation and part of key cellular processes. A sub-clade within Clade B, which includes Synechocystis sp. PCC 6803, shows a reverse trend in intergenic spacing. Our results suggest that while in situ formation and vertical descent may be a dominant mechanism of operon evolution in cyanobacteria, optimization of intergenic spacing and co-regulation are part of an ongoing process in the life-cycle of operons.

Human embryonic stem cell-derived mesodermal progenitors display substantially increased tissue formation compared to human mesenchymal stem cells under dynamic culture conditions in a packed bed/column bioreactor.

PubMed

de Peppo, Giuseppe Maria; Sladkova, Martina; Sjövall, Peter; Palmquist, Anders; Oudina, Karim; Hyllner, Johan; Thomsen, Peter; Petite, Hervé; Karlsson, Camilla

2013-01-01

Bone tissue engineering represents a promising strategy to obviate bone deficiencies, allowing the ex vivo construction of bone substitutes with unprecedented potential in the clinical practice. Considering that in the human body cells are constantly stimulated by chemical and mechanical stimuli, the use of bioreactor is emerging as an essential factor for providing the proper environment for the reproducible and large-scale production of the engineered substitutes. Human mesenchymal stem cells (hMSCs) are experimentally relevant cells but, regardless the encouraging results reported after culture under dynamic conditions in bioreactors, show important limitations for tissue engineering applications, especially considering their limited proliferative potential, loss of functionality following protracted expansion, and decline in cellular fitness associated with aging. On the other hand, we previously demonstrated that human embryonic stem cell-derived mesodermal progenitors (hES-MPs) hold great potential to provide a homogenous and unlimited source of cells for bone engineering applications. Based on prior scientific evidence using different types of stem cells, in the present study we hypothesized that dynamic culture of hES-MPs in a packed bed/column bioreactor had the potential to affect proliferation, expression of genes involved in osteogenic differentiation, and matrix mineralization, therefore resulting in increased bone-like tissue formation. The reported findings suggest that hES-MPs constitute a suitable alternative cell source to hMSCs and hold great potential for the construction of bone substitutes for tissue engineering applications in clinical settings.

Hydrate kinetics study in the presence of nonaqueous liquid by nuclear magnetic resonance spectroscopy and imaging.

PubMed

Susilo, Robin; Moudrakovski, Igor L; Ripmeester, John A; Englezos, Peter

2006-12-28

The dynamics of methane hydrate growth and decomposition were studied by nuclear magnetic resonance (NMR) spectroscopy and imaging (MRI). Three well-known large molecule guest substances (LMGS) were used as structure H hydrate formers: 2,2-dimethylbutane (NH), methylcyclohexane (MCH), tert-butyl methyl ether (TBME). In addition, the impact of a non-hydrate former (n-heptane/nC7) was studied. The methane diffusion and hydrate growth were monitored by recording the 2H NMR spectra at 253 K and approximately 4.5 MPa for 20 h. The results revealed that methane diffuses faster in TBME and NH, slower in nC7, and slowest in MCH. The TBME system gives the fastest hydrate formation kinetics followed by NH, MCH, and nC7. The conversion of water into hydrate was also observed. The imaging study showed that TBME has a strong affinity toward ice, which is not the case for the NH and MCH systems. The degree of ice packing was also found to affect the LMGS distribution between ice particles. Highly packed ice increases the mass transfer resistance and hence limits the contact between LMGS and ice. It was also found that "temperature ramping" above the ice point improves the conversion significantly. Finally, hydrates were found to dissociate quickly within the first hour at atmospheric pressure and subsequently at a much slower rate. Methane dissolved in LMGS was also seen. The residual methane in hydrate phase and dissolved in LMGS phase explain the faster kinetics during hydrate re-formation.

48 CFR 211.272 - Alternate preservation, packaging, and packing.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., packaging, and packing. 211.272 Section 211.272 Federal Acquisition Regulations System DEFENSE ACQUISITION... Requirements Documents 211.272 Alternate preservation, packaging, and packing. Use the provision at 252.211-7004, Alternate Preservation, Packaging, and Packing, in solicitations which include military...

Measure and dimension functions: measurability and densities

NASA Astrophysics Data System (ADS)

Mattila, Pertti; Mauldin, R. Daniel

1997-01-01

During the past several years, new types of geometric measure and dimension have been introduced; the packing measure and dimension, see [Su], [Tr] and [TT1]. These notions are playing an increasingly prevalent role in various aspects of dynamics and measure theory. Packing measure is a sort of dual of Hausdorff measure in that it is defined in terms of packings rather than coverings. However, in contrast to Hausdorff measure, the usual definition of packing measure requires two limiting procedures, first the construction of a premeasure and then a second standard limiting process to obtain the measure. This makes packing measure somewhat delicate to deal with. The question arises as to whether there is some simpler method for defining packing measure and dimension. In this paper, we find a basic limitation on this possibility. We do this by determining the descriptive set-theoretic complexity of the packing functions. Whereas the Hausdorff dimension function on the space of compact sets is Borel measurable, the packing dimension function is not. On the other hand, we show that the packing dimension functions are measurable with respect to the [sigma]-algebra generated by the analytic sets. Thus, the usual sorts of measurability properties used in connection with Hausdorff measure, for example measures of sections and projections, remain true for packing measure.

Microstructural characterization of random packings of cubic particles

DOE PAGES

Malmir, Hessam; Sahimi, Muhammad; Tabar, M. Reza Rahimi

2016-10-11

Understanding the properties of random packings of solid objects is of critical importance to a wide variety of fundamental scientific and practical problems. The great majority of the previous works focused, however, on packings of spherical and sphere-like particles. We report the first detailed simulation and characterization of packings of non-overlapping cubic particles. Such packings arise in a variety of problems, ranging from biological materials, to colloids and fabrication of porous scaffolds using salt powders. In addition, packing of cubic salt crystals arise in various problems involving preservation of pavements, paintings, and historical monuments, mineral-fluid interactions, CO 2 sequestration inmore » rock, and intrusion of groundwater aquifers by saline water. Not much is known, however, about the structure and statistical descriptors of such packings. We have developed a version of the random sequential addition algorithm to generate such packings, and have computed a variety of microstructural descriptors, including the radial distribution function, two-point probability function, orientational correlation function, specific surface, and mean chord length, and have studied the effect of finite system size and porosity on such characteristics. Here, the results indicate the existence of both spatial and orientational long-range order in the packing, which is more distinctive for higher packing densities.« less

Synthesis and liquid crystalline properties of mono-, di- and tri-O-alkyl pentaerythritol derivatives bearing tri-, di- or monogalactosyl heads: the effects of curvature of molecular packing on mesophase formation.

PubMed

Dumoulin, Fabienne; Lafont, Dominique; Huynh, Thai-Lê; Boullanger, Paul; Mackenzie, Grahame; West, Jon J; Goodby, John W

2007-01-01

Self-organisation and self-assembly are critical to the stability of synthetic and biological membranes. Of particular importance is consideration of the packing arrangements of the various molecular species. Both phospho- and glycolipids can pack in ways in which curvature can be introduced into self-organised or self-assembled systems. For instance, it is known that the degree of curvature can affect the structures of any condensed phases that are formed. In this article we report on a systematic study in which we have varied the shapes of glycolipids and examined the condensed phases that they form. In doing so, we have also unified the shape dependency of lyotropic liquid crystals with those of thermotropic liquid crystals. In order to undertake this systematic study a range of different pentaerythritol derivatives was synthesized, which covers combinations of one to three alkyl chains of different lengths (6,7,9,10,11,12,14,16 carbon atoms) and three to one galactosyl heads. Mono- and di-O-galactosyl derivatives were prepared directly by glycosylation of the corresponding alcohols using 2,3,4,6-tetra-O-benzoyl or acetyl-alpha-D-galactopyranosyl trichloroacetimidate or bromide as the donors; the tri-O-galactosyl derivatives were synthesized from O-alkyl-O-benzyl di-O-galactosyl pentaerythritol intermediates, followed by de-O-benzylation and glycosylation steps. All of the fully deprotected products were obtained by standard methods, and their self-organising and self-assembling properties examined.

Adsorption, folding, and packing of an amphiphilic peptide at the air/water interface.

PubMed

Engin, Ozge; Sayar, Mehmet

2012-02-23

Peptide oligomers play an essential role as model compounds for identifying key motifs in protein structure formation and protein aggregation. Here, we present our results, based on extensive molecular dynamics simulations, on adsorption, folding, and packing within a surface monolayer of an amphiphilic peptide at the air/water interface. Experimental results suggest that these molecules spontaneously form ordered monolayers at the interface, adopting a β-hairpin-like structure within the surface layer. Our results reveal that the β-hairpin structure can be observed both in bulk and at the air/water interface. However, the presence of an interface leads to ideal partitioning of the hydrophobic and hydrophilic residues, and therefore reduces the conformational space for the molecule and increases the stability of the hairpin structure. We obtained the adsorption free energy of a single β-hairpin at the air/water interface, and analyzed the enthalpic and entropic contributions. The adsorption process is favored by two main factors: (1) Free-energy reduction due to desolvation of the hydrophobic side chains of the peptide and release of the water molecules which form a cage around these hydrophobic groups in bulk water. (2) Reduction of the total air/water contact area at the interface upon adsorption of the peptide amphiphile. By performing mutations on the original molecule, we demonstrated the relative role of key design features of the peptide. Finally, by analyzing the potential of mean force among two peptides at the interface, we investigated possible packing mechanisms for these molecules within the surface monolayer. © 2012 American Chemical Society

Patient autoantibodies deplete postsynaptic muscle-specific kinase leading to disassembly of the ACh receptor scaffold and myasthenia gravis in mice

PubMed Central

Cole, R N; Ghazanfari, N; Ngo, S T; Gervásio, O L; Reddel, S W; Phillips, W D

2010-01-01

The postsynaptic muscle-specific kinase (MuSK) coordinates formation of the neuromuscular junction (NMJ) during embryonic development. Here we have studied the effects of MuSK autoantibodies upon the NMJ in adult mice. Daily injections of IgG from four MuSK autoantibody-positive myasthenia gravis patients (MuSK IgG; 45 mg day−1i.p. for 14 days) caused reductions in postsynaptic ACh receptor (AChR) packing as assessed by fluorescence resonance energy transfer (FRET). IgG from the patients with the highest titres of MuSK autoantibodies caused large (51–73%) reductions in postsynaptic MuSK staining (cf. control mice; P < 0.01) and muscle weakness. Among mice injected for 14 days with control and MuSK patient IgGs, the residual level of MuSK correlated with the degree of impairment of postsynaptic AChR packing. However, the loss of postsynaptic MuSK preceded this impairment of postsynaptic AChR. When added to cultured C2 muscle cells the MuSK autoantibodies caused tyrosine phosphorylation of MuSK and the AChR β-subunit, and internalization of MuSK from the plasma membrane. The results suggest a pathogenic mechanism in which MuSK autoantibodies rapidly deplete MuSK from the postsynaptic membrane leading to progressive dispersal of postsynaptic AChRs. Moreover, maintenance of postsynaptic AChR packing at the adult NMJ would appear to depend upon physical engagement of MuSK with the AChR scaffold, notwithstanding activation of the MuSK-rapsyn system of AChR clustering. PMID:20603331

Dry reforming of methane via plasma-catalysis: influence of the catalyst nature supported on alumina in a packed-bed DBD configuration

NASA Astrophysics Data System (ADS)

Brune, L.; Ozkan, A.; Genty, E.; Visart de Bocarmé, T.; Reniers, F.

2018-06-01

These days, the consideration of CO2 as a feedstock has become the subject of more interest. The reutilization of CO2 is already possible via cold plasma techniques operating at atmospheric pressure. A promising technology is the dielectric barrier discharge (DBD). In most cases DBDs exhibit a low energy efficiency for CO2 conversion. However, several routes can be used to increase this efficiency and hence, the product formation. One of these routes is the packed-bed DBD configuration with porous beads inside the gap of the DBD, which also allows the coupling of plasma with catalysis. Catalysts can be introduced in such a configuration to exploit the synergistic effect between plasma and catalytically active surfaces, leading to a more efficient process. In this article, the dry reforming of methane (DRM) is studied, which aims to convert both CO2 and CH4, another greenhouse gas, at the same time. The conversions and energy costs of the DRM process are investigated and compared in both the packed-bed DBD configurations containing catalysts (Co, Cu or Ni) and the classical DBD. The change in filamentary behavior is studied in detail and correlated with the obtained conversions using gas chromatography, mass spectrometry and using an oscilloscope. A characterization of the catalysts on the beads is also carried out. Both the CO2 and CH4 conversions are clearly increased with the plasma-catalysis. Moreover, CH4 conversions as high as 90% can be obtained in certain conditions with copper catalysts.

Young Adult Smokers' Neural Response to Graphic Cigarette Warning Labels.

PubMed

Green, Adam E; Mays, Darren; Falk, Emily B; Vallone, Donna; Gallagher, Natalie; Richardson, Amanda; Tercyak, Kenneth P; Abrams, David B; Niaura, Raymond S

2016-06-01

The study examined young adult smokers' neural response to graphic warning labels (GWLs) on cigarette packs using functional magnetic resonance imaging (fMRI). Nineteen young adult smokers ( M age 22.9, 52.6% male, 68.4% non-white, M 4.3 cigarettes/day) completed pre-scan, self-report measures of demographics, cigarette smoking behavior, and nicotine dependence, and an fMRI scanning session. During the scanning session participants viewed cigarette pack images (total 64 stimuli, viewed 4 seconds each) that varied based on the warning label (graphic or visually occluded control) and pack branding (branded or plain packaging) in an event-related experimental design. Participants reported motivation to quit (MTQ) in response to each image using a push-button control. Whole-brain blood oxygenation level-dependent (BOLD) functional images were acquired during the task. GWLs produced significantly greater self-reported MTQ than control warnings ( p < .001). Imaging data indicate stronger neural activation in response to GWLs than the control warnings at a cluster-corrected threshold p <.001 in medial prefrontal cortex, amygdala, medial temporal lobe, and occipital cortex. There were no significant differences in response to warnings on branded versus plain cigarette packages. In this sample of young adult smokers, GWLs promoted neural activation in brain regions involved in cognitive and affective decision-making and memory formation and the effects of GWLs did not differ on branded or plain cigarette packaging. These findings complement other recent neuroimaging GWL studies conducted with older adult smokers and with adolescents by demonstrating similar patterns of neural activation in response to GWLs among young adult smokers.

Young people's perceptions of cigarette packaging and plain packaging: an online survey.

PubMed

Moodie, Crawford; Ford, Allison; Mackintosh, Anne Marie; Hastings, Gerard

2012-01-01

In the United Kingdom, with most marketing channels prohibited, packaging is one of the few remaining ways that tobacco companies can promote their products. An online survey with young people aged 10-17 years (N = 658) was used to explore why youth choose cigarettes, perceptions of pack color, and perceptions of plain (nonbranded) cigarette packaging. Young people were also shown an image of 3 plain packs, which differed by shape and method of opening, and asked which they liked most and thought others their age would smoke. Price and what significant others smoke were key factors for choosing cigarettes, with packaging also an important influence. More than a third of the sample associated lighter pack color with weak tasting and less harmful cigarettes. Plain packs were rated negatively as were perceptions of plain pack users. One in 3 showed a preference for either a narrow "perfume type" plain pack or a plain "slide" pack that opened from the side, and 1 in 3 also thought that young people would smoke these packs. Packaging appears to both attract young people and mislead them about product strength and relative harm. Innovative pack construction (novel pack shape and method of opening) and the use of color are instrumental in these effects. The findings therefore suggest that any move to plain packaging should not only consider the benefits of removing branding (including color) but also of standardizing pack construction in terms of shape and method of opening.

Packing microstructure and local density variations of experimental and computational pebble beds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Auwerda, G. J.; Kloosterman, J. L.; Lathouwers, D.

2012-07-01

In pebble bed type nuclear reactors the fuel is contained in graphite pebbles, which form a randomly stacked bed with a non-uniform packing density. These variations can influence local coolant flow and power density and are a possible cause of hotspots. To analyse local density variations computational methods are needed that can generate randomly stacked pebble beds with a realistic packing structure on a pebble-to-pebble level. We first compare various properties of the local packing structure of a computed bed with those of an image made using computer aided X-ray tomography, looking at properties in the bulk of the bedmore » and near the wall separately. Especially for the bulk of the bed, properties of the computed bed show good comparison with the scanned bed and with literature, giving confidence our method generates beds with realistic packing microstructure. Results also show the packing structure is different near the wall than in the bulk of the bed, with pebbles near the wall forming ordered layers similar to hexagonal close packing. Next, variations in the local packing density are investigated by comparing probability density functions of the packing fraction of small clusters of pebbles throughout the bed. Especially near the wall large variations in local packing fractions exists, with a higher probability for both clusters of pebbles with low (<0.6) and high (>0.65) packing fraction, which could significantly affect flow rates and, together with higher power densities, could result in hotspots. (authors)« less

7 CFR 51.2840 - Export packing requirements.

Code of Federal Regulations, 2010 CFR

2010-01-01

... 7 Agriculture 2 2010-01-01 2010-01-01 false Export packing requirements. 51.2840 Section 51.2840 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards...) Export Packing Requirements § 51.2840 Export packing requirements. Onions specified as meeting Export...

Packing of flexible 2D materials in vesicles

NASA Astrophysics Data System (ADS)

Zou, Guijin; Yi, Xin; Zhu, Wenpeng; Gao, Huajian

2018-06-01

To understand the mechanics of cellular packing of two-dimensional (2D) materials, we perform systematic molecular dynamics simulations and theoretical analysis to investigate the packing of a flexible circular sheet in a spherical vesicle and the 2D packing problem of a strip in a cylindrical vesicle. Depending on the system dimensions and the bending rigidity ratio between the confined sheet and the vesicle membrane, a variety of packing morphologies are observed, including a conical shape, a shape of three-fold symmetry, a cylindrically curved shape, an axisymmetrically buckled shape, as well as the initial circular shape. A set of buckling analyses lead to phase diagrams of the packing morphologies of the encapsulated sheets. These results may have important implications on the mechanism of intracellular packing and toxicity of 2D materials.

An Amino Acid Packing Code for α-helical Structure and Protein Design

PubMed Central

Joo, Hyun; Chavan, Archana G.; Phan, Jamie; Day, Ryan; Tsai, Jerry

2012-01-01

This work demonstrates that all packing in α-helices can be simplified to repetitive patterns of a single motif: the knob-socket. Using the precision of Voronoi Polyhedra/Deluaney Tessellations to identify contacts, the knob-socket is a 4 residue tetrahedral motif: a knob residue on one α-helix packs into the 3 residue socket on another α-helix. The principle of the knob-socket model relates the packing between levels of protein structure: the intra-helical packing arrangements within secondary structure that permit inter-helix tertiary packing interactions. Within an α-helix, the 3 residue sockets arrange residues into a uniform packing lattice. Inter-helix packing results from a definable pattern of interdigitated knob-socket motifs between 2 α-helices. Furthermore, the knob-socket model classifies 3 types of sockets: 1) free: favoring only intra-helical packing, 2) filled: favoring inter-helical interactions and 3) non: disfavoring α-helical structure. The amino acid propensities in these 3 socket classes essentially represent an amino acid code for structure in α-helical packing. Using this code, a novel yet straightforward approach for the design of α-helical structure was used to validate the knob-socket model. Unique sequences for 3 peptides were created to produce a predicted amount of α-helical structure: mostly helical, some helical, and no-helix. These 3 peptides were synthesized and helical content assessed using CD spectroscopy. The measured α-helicity of each peptide was consistent with the expected predictions. These results and analysis demonstrate that the knob-socket motif functions as the basic unit of packing and presents an intuitive tool to decipher the rules governing packing in protein structure. PMID:22426125

Perceptions of plain packaging among young adult roll-your-own smokers in France: a naturalistic approach.

PubMed

Gallopel-Morvan, Karine; Moodie, Crawford; Eker, Figen; Beguinot, Emmanuelle; Martinet, Yves

2015-03-01

We explored, for the first time, young adult roll-your-own smokers' response to using plain packaging in real-world settings. Naturalistic research was employed, where 133 French young adult smokers (18-25 years of age) used plain roll-your-own packs for 10 days; the plain packs they were provided with contained their usual brand of rolling tobacco and displayed the name of their usual brand. Participants were recruited in five cities in France (Paris, Marseille, Metz, Nantes, Toulouse) and completed two questionnaires to measure their response to their own branded packs and the plain packs. Both questionnaires assessed pack perceptions, brand attachment, product perceptions (eg, taste, quality, natural), feelings about smoking (satisfying, pleasurable), feelings when using the pack in front of others (embarrassment, image), warning response (credibility, awareness of risks) and smoking-related behaviour (eg, consumption, quitting). Compared to their own fully branded packs, plain packs were associated with less positive pack and product perceptions, lower brand attachment and less positive feelings about smoking and feelings when using the pack in front of others. Participants were also more likely to report feeling like reducing consumption and quitting when using the plain packs, and more likely to feel like missing out on rolling a cigarette. No significant differences between the two pack types (plain and branded) were found in terms of credibility of warnings and perceptions of level of tar. The study suggests that the impacts of plain packaging for roll-your-own cigarette smokers are the same as for smokers of factory-made cigarettes. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

The pack size effect: Influence on consumer perceptions of portion sizes.

PubMed

Hieke, Sophie; Palascha, Aikaterini; Jola, Corinne; Wills, Josephine; Raats, Monique M

2016-01-01

Larger portions as well as larger packs can lead to larger prospective consumption estimates, larger servings and increased consumption, described as 'portion-size effects' and 'pack size effects'. Although related, the effects of pack sizes on portion estimates have received less attention. While it is not possible to generalize consumer behaviour across cultures, external cues taken from pack size may affect us all. We thus examined whether pack sizes influence portion size estimates across cultures, leading to a general 'pack size effect'. We compared portion size estimates based on digital presentations of different product pack sizes of solid and liquid products. The study with 13,177 participants across six European countries consisted of three parts. Parts 1 and 2 asked participants to indicate the number of portions present in a combined photographic and text-based description of different pack sizes. The estimated portion size was calculated as the quotient of the content weight or volume of the food presented and the number of stated portions. In Part 3, participants stated the number of food items that make up a portion when presented with packs of food containing either a small or a large number of items. The estimated portion size was calculated as the item weight times the item number. For all three parts and across all countries, we found that participants' portion estimates were based on larger portions for larger packs compared to smaller packs (Part 1 and 2) as well as more items to make up a portion (Part 3); hence, portions were stated to be larger in all cases. Considering that the larger estimated portions are likely to be consumed, there are implications for energy intake and weight status. Copyright © 2015 Elsevier Ltd. All rights reserved.

Higher prices in Jamaica.

PubMed

1982-03-01

Price increases in the Jamaica CSM program went into effect on August 31, 1981. The program began in 1975. While the need for higher prices has been under discussion for the past 3 years, this is the 1st time the requisite approval from the Jamaica Price Commission has been obtained. The Jamaica National Family Planning Board (JNFPB) reports that the Panther 3-pack (condom) is up US$0.15 to US$0.30. Each Perle package (oral contraceptive) was increased by US$0.20. Single cycle Perle now sells for US$0.50, and 3-pack Perle sells for US$1.10. The 6-year price stagnation experienced by the CSM program resulted in a decreasing operational budget as program costs continued to rise. Marketing costs alone during this period escalated by 100-300%. For example, Panther pop-up display cartons cost the project US 16U each in 1975. By 1979 the same product cost US 49U. Newspaper advertisements have increased from the 1975 cost of US$68.00 to nearly $200.00 per placement. The overall inflation rate in Jamaica during the last 5 years has averaged more than 20% annually. In the face of these rising costs, outlet expansion for Perle has been prevented, wholesaler margins have been unavailable, and new retailer training has been discontinued. It is projected that the new prices will result in an annual increased revenues of US$80,000 which will be used to reinstate these essential marketing activities. The JNFPB is also planning to introduce a Panther 12-pack and Panther strips to the CSM product line. According to Marketing Manager Aston Evans, "We believe the public is now ready for this type of packaging" which is scheduled to be available soon. Panther is presently only available in a 3-pack, but annual sales have been steady. The new 12-pack will be stocked on supermarket shelves to provide higher product visibility and wider distribution. The selling price has been set as US$1.20 and is expected to yield a 25% increase in sales during the 1st year. A complete sales promotion and advertising campaign will accompany the 12-pack introduction. The marketing plan for Panther strips emphasizes placement in government and private sector offices and factories throughout the country. In the deep rural areas the strips will be available for sale in shops, bars, nightclubs, and other distribution points. full text

The effect of relatedness and pack size on territory overlap in African wild dogs.

PubMed

Jackson, Craig R; Groom, Rosemary J; Jordan, Neil R; McNutt, J Weldon

2017-01-01

Spacing patterns mediate competitive interactions between conspecifics, ultimately increasing fitness. The degree of territorial overlap between neighbouring African wild dog ( Lycaon pictus ) packs varies greatly, yet the role of factors potentially affecting the degree of overlap, such as relatedness and pack size, remain unclear. We used movement data from 21 wild dog packs to calculate the extent of territory overlap (20 dyads). On average, unrelated neighbouring packs had low levels of overlap restricted to the peripheral regions of their 95% utilisation kernels. Related neighbours had significantly greater levels of peripheral overlap. Only one unrelated dyad included overlap between 75%-75% kernels, but no 50%-50% kernels overlapped. However, eight of 12 related dyads overlapped between their respective 75% kernels and six between the frequented 50% kernels. Overlap between these more frequented kernels confers a heightened likelihood of encounter, as the mean utilisation intensity per unit area within the 50% kernels was 4.93 times greater than in the 95% kernels, and 2.34 times greater than in the 75% kernels. Related packs spent significantly more time in their 95% kernel overlap zones than did unrelated packs. Pack size appeared to have little effect on overlap between related dyads, yet among unrelated neighbours larger packs tended to overlap more onto smaller packs' territories. However, the true effect is unclear given that the model's confidence intervals overlapped zero. Evidence suggests that costly intraspecific aggression is greatly reduced between related packs. Consequently, the tendency for dispersing individuals to establish territories alongside relatives, where intensively utilised portions of ranges regularly overlap, may extend kin selection and inclusive fitness benefits from the intra-pack to inter-pack level. This natural spacing system can affect survival parameters and the carrying capacity of protected areas, having important management implications for intensively managed populations of this endangered species.

Distribution of new graphic warning labels: Are tobacco companies following regulations?

PubMed

Wilson, Nick; Peace, Jo; Li, Judy; Edwards, Richard; Hoek, Janet; Stanley, James; Thomson, George

2009-08-25

To test the hypothesis that tobacco companies would not follow a regulation that required seven new graphic health warnings (GHWs) to be evenly distributed on cigarette packs and that they would distribute fewer packs featuring warnings regarded by smokers as being more disturbing. Cross-sectional survey of purchased packs (n = 168) and street-collected discarded packs (convenience sample of New Zealand cities and towns, n = 1208 packs) with statistical analysis of seven types of new GHWs. A priori warning impact was judged using three criteria, which were tested against data from depth interviews with retailers. The GHWs on the purchased packs and street-collected packs both showed a distribution pattern that was generally consistent with the hypothesis ie, there were disproportionately more packs featuring images judged as "least disturbing" and disproportionately fewer of those with warnings judged "more disturbing". The overall patterns were statistically significant, suggesting an unequal frequency of the different warnings for both purchased (p < 0.0001) and street-collected packs (p = 0.035). One of the least disturbing images (of a "corpse with toe-tag") dominated the distribution in both samples. Further analysis of the street-collected packs revealed that this image appeared disproportionately more frequently on manufactured cigarettes made by each of the three largest New Zealand tobacco companies. Although stock clustering could explain the purchase pack result, there were no obvious reasons why the same uneven warning distribution was also evident among the street-collected packs. These results suggest that tobacco companies are not following the regulations, which requires even distribution of the seven different GHWs on cigarette packs; further monitoring is required to estimate the extent of this non-compliance. As an immediate measure, governments should strictly enforce all regulations applying to health warnings, particularly given that these are an effective tobacco control intervention that cost tax payers nothing.

Retail price and point of sale display of tobacco in the UK: a descriptive study of small retailers.

PubMed

Spanopoulos, Dionysis; Ratschen, Elena; McNeill, Ann; Britton, John

2012-01-01

Since the implementation of the 2002 Tobacco Advertising and Promotion Act, point-of-sale (PoS) tobacco displays are one of few remaining means of communication between the tobacco industry and customers in the UK. This study aimed to explore the characteristics of tobacco displays in a UK city, and particularly to assess the tobacco prices and promotional offers, types and pack sizes on display. Digital pictures of PoS displays were taken in 117 small retail shops in Nottingham in mid 2010. Data were analysed using Windows Photo Gallery software and SPSS version 16. Just over half (52%) of cigarette packs on display were packs of 20, and 43% packs of 10. Cigarette prices differed substantially between brands, ranging from £4.19 to £6.85 for 20-packs, and from £2.12 to £3.59 for 10-packs. Forty four percent of cigarette packs and 40% of RYO (Roll-Your-Own) tobacco pouches, almost exclusively lower priced brands, were displayed with a pricemark, implying a promotional price offer. Eighty percent of 20-pack cigarette brand or brand variants on sale were priced below the EU-defined Most Popular Price Category (MPPC) for the UK in 2010; 45% were priced below the Weighted Average Price (WAP), which replaced the MPPC in 2011. PoS displays communicate value by displaying a high proportion of lower cost brands, and smaller and hence lower-cost packs, and by displaying price discounts on packs. The MPPC substantially overestimated the prices at which most 20-cigarette packs were available. Removal of PoS displays will prevent this means of price marketing but our study also suggests that minimum pricing of 20-pack cigarettes, prohibition of sale of cigarettes in packs less than 20, and plain packaging to prevent pricemarking are necessary if price is to be used effectively as a tobacco control measure.

Retail Price and Point of Sale Display of Tobacco in the UK: A Descriptive Study of Small Retailers

PubMed Central

Spanopoulos, Dionysis; Ratschen, Elena; McNeill, Ann; Britton, John

2012-01-01

Background Since the implementation of the 2002 Tobacco Advertising and Promotion Act, point-of-sale (PoS) tobacco displays are one of few remaining means of communication between the tobacco industry and customers in the UK. This study aimed to explore the characteristics of tobacco displays in a UK city, and particularly to assess the tobacco prices and promotional offers, types and pack sizes on display. Methods Digital pictures of PoS displays were taken in 117 small retail shops in Nottingham in mid 2010. Data were analysed using Windows Photo Gallery software and SPSS version 16. Results Just over half (52%) of cigarette packs on display were packs of 20, and 43% packs of 10. Cigarette prices differed substantially between brands, ranging from £4.19 to £6.85 for 20-packs, and from £2.12 to £3.59 for 10-packs. Forty four percent of cigarette packs and 40% of RYO (Roll-Your-Own) tobacco pouches, almost exclusively lower priced brands, were displayed with a pricemark, implying a promotional price offer. Eighty percent of 20-pack cigarette brand or brand variants on sale were priced below the EU-defined Most Popular Price Category (MPPC) for the UK in 2010; 45% were priced below the Weighted Average Price (WAP), which replaced the MPPC in 2011. Conclusion PoS displays communicate value by displaying a high proportion of lower cost brands, and smaller and hence lower-cost packs, and by displaying price discounts on packs. The MPPC substantially overestimated the prices at which most 20-cigarette packs were available. Removal of PoS displays will prevent this means of price marketing but our study also suggests that minimum pricing of 20-pack cigarettes, prohibition of sale of cigarettes in packs less than 20, and plain packaging to prevent pricemarking are necessary if price is to be used effectively as a tobacco control measure. PMID:22242183

Experimental and Numerical Investigation of Two Dimensional CO2 Adsorption/Desorption in Packed Sorption Beds under Non-Ideal Flows

NASA Technical Reports Server (NTRS)

Mohamadinejad, H.; Knox, J. C.; Smith, J. E.; Croomes, Scott (Technical Monitor)

2001-01-01

The experimental results of CO2 adsorption and desorption in a packed column indicated that the concentration wave front at the center of the packed column differs from those which are close to the wall of column filled with adsorbent material even though the ratio of column diameter to the particle size is greater than 20. The comparison of the experimental results with one dimensional model of packed column shows that in order to simulate the average breakthrough in a packed column a two dimensional (radial and axial) model of packed column is needed. In this paper the mathematical model of a non-slip flow through a packed column with 2 inches in diameter and 18 inches in length filled with 5A zeolite pellets is presented. The comparison of experimental results of CO2 absorption and desorption for the mixed and central breakthrough of the packed column with numerical results is also presented.

Cold therapy for the management of pain associated with deep breathing and coughing post-cardiac surgery.

PubMed

Chailler, Myrianne; Ellis, Jacqueline; Stolarik, Anne; Woodend, Kirsten

2010-01-01

Coughing has been identified as the most painful experience post cardiac surgery. Participants (n = 32), in a randomized crossover trial, applied a frozen gel pack to their sternal incision dressing before performing deep breathing and coughing (DB & C) exercises. Pain scores from 0 to 10 at rest were compared with pain scores post DB & C with and without the gel pack. Participants were also asked to describe their sensations with the frozen gel pack, as well as their preferences for gel pack application. The repeated measures analysis of variance revealed a significant reduction in pain scores between pre- and post-application of the gel pack (F = 28.69, p < .001). There were 22 (69%) participants who preferred the application of the gel pack compared with no gel pack. All 32 (100%) participants would reapply the gel pack in the future. This study demonstrates that cold therapy can be used to manage sternal incisional pain when DB & C.

An improved theoretical electrochemical-thermal modelling of lithium-ion battery packs in electric vehicles

NASA Astrophysics Data System (ADS)

Amiribavandpour, Parisa; Shen, Weixiang; Mu, Daobin; Kapoor, Ajay

2015-06-01

A theoretical electrochemical thermal model combined with a thermal resistive network is proposed to investigate thermal behaviours of a battery pack. The combined model is used to study heat generation and heat dissipation as well as their influences on the temperatures of the battery pack with and without a fan under constant current discharge and variable current discharge based on electric vehicle (EV) driving cycles. The comparison results indicate that the proposed model improves the accuracy in the temperature predication of the battery pack by 2.6 times. Furthermore, a large battery pack with four of the investigated battery packs in series is simulated in the presence of different ambient temperatures. The simulation results show that the temperature of the large battery pack at the end of EV driving cycles can reach to 50 °C or 60 °C in high ambient temperatures. Therefore, thermal management system in EVs is required to maintain the battery pack within the safe temperature range.

American Spirit Pack Descriptors and Perceptions of Harm: A Crowdsourced Comparison of Modified Packs.

PubMed

Pearson, Jennifer L; Richardson, Amanda; Feirman, Shari P; Villanti, Andrea C; Cantrell, Jennifer; Cohn, Amy; Tacelosky, Michael; Kirchner, Thomas R

2016-08-01

In 2015, the Food and Drug Administration issued warnings to three tobacco manufacturers who label their cigarettes as "additive-free" and/or "natural" on the grounds that they make unauthorized reduced risk claims. The goal of this study was to examine US adults' perceptions of three American Spirit (AS) pack descriptors ("Made with Organic Tobacco," "100% Additive-Free," and "100% US Grown Tobacco") to assess if they communicate reduced risk. In September 2012, three cross-sectional surveys were posted on Amazon Mechanical Turk. Adult participants evaluated the relative harm of a Marlboro Red pack versus three different AS packs with the descriptors "Made with Organic Tobacco," "100% Additive-Free," or "100% US Grown Tobacco" (Survey 1; n = 461); a Marlboro Red pack versus these AS packs modified to exclude descriptors (Survey 2; n = 857); and unmodified versus modified AS pack images (Survey 3; n = 1001). The majority of Survey 1 participants rated the unmodified AS packs as less harmful than the Marlboro Red pack; 35.4%-58.8% of Survey 2 participants also rated the modified (no claims) packs as less harmful than Marlboro Red. In these surveys, prior use of AS cigarettes was associated with reduced perceptions of risk (adjusted odds ratio [AOR] 1.59-2.40). "Made with Organic Tobacco" and "100% Additive-Free" were associated with reduced perceptions of risk when comparing the modified versus the unmodified AS packs (Survey 3). Data suggest that these AS pack descriptors communicate reduced harm messages to consumers. Findings have implications for regulatory actions related to product labeling and packaging. These findings provide additional evidence that the "Made with Organic Tobacco," "100% Additive-Free," and "100% US Grown" descriptors, as well as other aspects of the AS pack design, communicate reduced harm to non-, current, and former smokers. Additionally, they provide support for the importance of FDA's 2015 warning to Santa Fe Natural Tobacco Company on "100% Additive Free" as an unauthorized modified risk claim. © The Author 2016. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Deployment of Large-Size Shell Constructions by Internal Pressure

NASA Astrophysics Data System (ADS)

Pestrenin, V. M.; Pestrenina, I. V.; Rusakov, S. V.; Kondyurin, A. V.

2015-11-01

A numerical study on the deployment pressure (the minimum internal pressure bringing a construction from the packed state to the operational one) of large laminated CFRP shell structures is performed using the ANSYS engineering package. The shell resists both membrane and bending deformations. Structures composed of shell elements whose median surface has an involute are considered. In the packed (natural) states of constituent elements, the median surfaces coincide with their involutes. Criteria for the termination of stepwise solution of the geometrically nonlinear problem on determination of the deployment pressure are formulated, and the deployment of cylindrical, conical (full and truncated cones), and large-size composite shells is studied. The results obtained are shown by graphs illustrating the deployment pressure in relation to the geometric and material parameters of the structure. These studies show that large pneumatic composite shells can be used as space and building structures, because the deployment pressure in them only slightly differs from the excess pressure in pneumatic articles made from films and soft materials.

Status and future trends of radiation processing in Brazil

NASA Astrophysics Data System (ADS)

Lugão, A. B.; Andrade, E.; Silva, L. G.

1998-06-01

Electron-beam and gamma irradiation of polymers are widely applied in Brazil today. The main applications are: - radio-induced crosslinking of wire and cable for automobile and appliance industry; - heat shrinkable tubes for appliance, automobile and electronic; - heat shrinkable packing for food processing industry; - sterilization of medical supplies and so on. Nevertheless, there are only a few industrial facilities about 20 years old in full operation at present and there are some new low energy machines for food packing. The reason for such absence of investment in this area was studied and the relation between automobile and appliance production with radiation processing was fully demonstrated for Brazil case. In conclusion, it was shown that the industry of radiation processing of polymers is likely to experience a strong growth based on the continuous increase in the production of automobiles and appliances. The R&D activities of IPEN are an important support for developing the necessary technology and developing the necessary confidence in the radiation as tool for economical and social growth.

Automated packing systems: review of industrial implementations

NASA Astrophysics Data System (ADS)

Whelan, Paul F.; Batchelor, Bruce G.

1993-08-01

A rich theoretical background to the problems that occur in the automation of material handling can be found in operations research, production engineering, systems engineering and automation, more specifically machine vision, literature. This work has contributed towards the design of intelligent handling systems. This paper will review the application of these automated material handling and packing techniques to industrial problems. The discussion will also highlight the systems integration issues involved in these applications. An outline of one such industrial application, the automated placement of shape templates on to leather hides, is also discussed. The purpose of this system is to arrange shape templates on a leather hide in an efficient manner, so as to minimize the leather waste, before they are automatically cut from the hide. These pieces are used in the furniture and car manufacturing industries for the upholstery of high quality leather chairs and car seats. Currently this type of operation is semi-automated. The paper will outline the problems involved in the full automation of such a procedure.