Syntheses, structures and properties of 3D inorganic-organic hybrid frameworks constructed from lanthanide polymer and Keggin-type tungstosilicate

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

Gao Yuanzhe; College of Chemistry and Material Science, Hebei Normal University, Shijiazhuang, Hebei 050016; Xu Yanqing, E-mail: xyq@bit.edu.c

2010-05-15

Inorganic-organic hybrid frameworks, namely [Ce(H{sub 2}O){sub 3}(pdc)]{sub 4}[SiW{sub 12}O{sub 40}].6H{sub 2}O 1, [M(H{sub 2}O){sub 4}(pdc)]{sub 4}[SiW{sub 12}O{sub 40}].2H{sub 2}O (M=Ce for 2a, La for 2b, Nd for 2c; H{sub 2}pdc=pyridine-2,6-dicarboxylic acid) were assembled through incorporation of Keggin-type heteropolyanion [SiW{sub 12}O{sub 40}]{sup 4-} within the voids of lanthanides-pdc network as pillars or guests under hydrothermal condition. Single-crystal X-ray analyses of these crystals reveal that compound 1 presents 3D pillar-layered framework with the [SiW{sub 12}O{sub 40}]{sup 4-} anions located on the square voids of the two-dimensional Ce-pdc bilayer. Compounds 2a-c are isostructural and constructed from 3D Ln-pdc-based metal-organic framework (MOF) incorporating noncoordinatingmore » guests Keggin structure [SiW{sub 12}O{sub 40}]{sup 4-}. Solid-state properties of compounds 1 and 2a-c such as thermal stability and photoluminescence have been further investigated. - Graphical abstract: Two types of new inorganic-organic hybrid frameworks through incorporation of Keggin-type heteropolyanion [SiW{sub 12}O{sub 40}]{sup 4-} within the voids of lanthanides-pdc network as pillars or guests under hydrothermal condition were successfully assembled. Solid-state properties of compounds 1 and 2a such as thermal stability and photoluminescence have been further investigated.« less

Numerical study of the effects of surface topography and chemistry on the wetting transition using the string method.

PubMed

Zhang, Yanan; Ren, Weiqing

2014-12-28

Droplets on a solid surface patterned with microstructures can exhibit the composite Cassie-Baxter (CB) state or the wetted Wenzel state. The stability of the CB state is determined by the energy barrier separating it from the wetted state. In this work, we study the CB to Wenzel transition using the string method [E et al., J. Chem. Phys. 126, 164103 (2007); W. Ren and E. Vanden-Eijnden, J. Chem. Phys. 138, 134105 (2013)]. We compute the transition states and energy barriers for a three-dimensional droplet on patterned surfaces. The liquid-vapor coexistence is modeled using the mean field theory. Numerical results are obtained for surfaces patterned with straight pillars and nails, respectively. It is found that on both type of surfaces, wetting occurs via infiltration of the liquid in a single groove. The reentrant geometry of nails creates large energy barrier for the wetting of the solid surface compared to straight pillars. We also study the effect of surface chemistry, pillar height, and inter-pillar spacing on the energy barrier and compare it with nails.

Numerical study of the effects of surface topography and chemistry on the wetting transition using the string method

NASA Astrophysics Data System (ADS)

Zhang, Yanan; Ren, Weiqing

2014-12-01

Droplets on a solid surface patterned with microstructures can exhibit the composite Cassie-Baxter (CB) state or the wetted Wenzel state. The stability of the CB state is determined by the energy barrier separating it from the wetted state. In this work, we study the CB to Wenzel transition using the string method [E et al., J. Chem. Phys. 126, 164103 (2007); W. Ren and E. Vanden-Eijnden, J. Chem. Phys. 138, 134105 (2013)]. We compute the transition states and energy barriers for a three-dimensional droplet on patterned surfaces. The liquid-vapor coexistence is modeled using the mean field theory. Numerical results are obtained for surfaces patterned with straight pillars and nails, respectively. It is found that on both type of surfaces, wetting occurs via infiltration of the liquid in a single groove. The reentrant geometry of nails creates large energy barrier for the wetting of the solid surface compared to straight pillars. We also study the effect of surface chemistry, pillar height, and inter-pillar spacing on the energy barrier and compare it with nails.

Contact angle of a nanodrop on a nanorough solid surface.

PubMed

Berim, Gersh O; Ruckenstein, Eli

2015-02-21

The contact angle of a cylindrical nanodrop on a nanorough solid surface is calculated, for both hydrophobic and hydrophilic surfaces, using the density functional theory. The emphasis of the paper is on the dependence of the contact angle on roughness. The roughness is modeled by rectangular pillars of infinite length located on the smooth surface of a substrate, with fluid-pillar interactions different in strength from the fluid-substrate ones. It is shown that for hydrophobic substrates the trend of the contact angle to increase with increasing roughness, which was noted in all previous studies, is not universally valid, but depends on the fluid-pillar interactions, pillar height, interpillar distance, as well as on the size of the drop. For hydrophilic substrate, an unusual kink-like dependence of the contact angle on the nanodrop size is found which is caused by the change in the location of the leading edges of the nanodrop on the surface. It is also shown that the Wenzel and Cassie-Baxter equations can not explain all the peculiarities of the contact angle of a nanodrop on a nanorough surface.

Band gap in tubular pillar phononic crystal plate.

PubMed

Shu, Fengfeng; Liu, Yongshun; Wu, Junfeng; Wu, Yihui

2016-09-01

In this paper, a phononic crystal (PC) plate with tubular pillars is presented and investigated. The band structures and mode displacement profiles are calculated by using finite element method. The result shows that a complete band gap opens when the ratio of the pillar height to the plate thickness is about 1.6. However, for classic cylinder pillar structures, a band gap opens when the ratio is equal or greater than 3. A tubular pillar design with a void room in it enhances acoustic multiple scattering and gives rise to the opening of the band gap. In order to verify it, a PC structure with double tubular pillars different in size (one within the other) is introduced and a more than 2times band gap enlargement is observed. Furthermore, the coupling between the resonant mode and the plate mode around the band gap is characterized, as well as the effect of the geometrical parameters on the band gap. The behavior of such structure could be utilized to design a pillar PC with stronger structural stability and to enlarge band gaps. Copyright © 2016 Elsevier B.V. All rights reserved.

Friction Hydro-Pillar Processing of a High Carbon Steel: Joint Structure and Properties

NASA Astrophysics Data System (ADS)

Kanan, Luis Fernando; Vicharapu, Buchibabu; Bueno, Antonio Fernando Burkert; Clarke, Thomas; De, Amitava

2018-04-01

A coupled experimental and theoretical study is reported here on friction hydro-pillar processing of AISI 4140 steel, which is a novel solid-state joining technique to repair and fill crack holes in thick-walled components by an external stud. The stud is rotated and forced to fill a crack hole by plastic flow. During the process, frictional heating occurs along the interface of the stud and the wall of crack hole leading to thermal softening of the stud that eases its plastic deformation. The effect of the stud force, its rotational speed and the total processing time on the rate of heat generation and resulting transient temperature field is therefore examined to correlate the processing variables with the joint structure and properties in a systematic and quantitative manner, which is currently scarce in the published literature. The results show that a gentler stud force rate and greater processing time can promote proper filling of the crack hole and facilitate a defect-free joint between the stud and original component.

Identifying Structural Flow Defects in Disordered Solids Using Machine-Learning Methods

NASA Astrophysics Data System (ADS)

Cubuk, E. D.; Schoenholz, S. S.; Rieser, J. M.; Malone, B. D.; Rottler, J.; Durian, D. J.; Kaxiras, E.; Liu, A. J.

2015-03-01

We use machine-learning methods on local structure to identify flow defects—or particles susceptible to rearrangement—in jammed and glassy systems. We apply this method successfully to two very different systems: a two-dimensional experimental realization of a granular pillar under compression and a Lennard-Jones glass in both two and three dimensions above and below its glass transition temperature. We also identify characteristics of flow defects that differentiate them from the rest of the sample. Our results show it is possible to discern subtle structural features responsible for heterogeneous dynamics observed across a broad range of disordered materials.

Experimental determination of gamma-ray discrimination in pillar-structured thermal neutron detectors under high gamma-ray flux

DOE PAGES

Shao, Qinghui; Conway, Adam M.; Voss, Lars F.; ...

2015-08-04

Silicon pillar structures filled with a neutron converter material ( 10B) are designed to have high thermal neutron detection efficiency with specific dimensions of 50 μm pillar height, 2 μm pillar diameter and 2 μm spacing between adjacent pillars. In this paper, we have demonstrated such a detector has a high neutron-to-gamma discrimination of 10 6 with a high thermal neutron detection efficiency of 39% when exposed to a high gamma-ray field of 10 9 photons/cm 2s.

Numerical study of the effects of surface topography and chemistry on the wetting transition using the string method

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

Zhang, Yanan, E-mail: ynzhang@suda.edu.cn; Ren, Weiqing, E-mail: matrw@nus.edu.sg; Institute of High Performance Computing, Singapore 138632

2014-12-28

Droplets on a solid surface patterned with microstructures can exhibit the composite Cassie-Baxter (CB) state or the wetted Wenzel state. The stability of the CB state is determined by the energy barrier separating it from the wetted state. In this work, we study the CB to Wenzel transition using the string method [E et al., J. Chem. Phys. 126, 164103 (2007); W. Ren and E. Vanden-Eijnden, J. Chem. Phys. 138, 134105 (2013)]. We compute the transition states and energy barriers for a three-dimensional droplet on patterned surfaces. The liquid-vapor coexistence is modeled using the mean field theory. Numerical results aremore » obtained for surfaces patterned with straight pillars and nails, respectively. It is found that on both type of surfaces, wetting occurs via infiltration of the liquid in a single groove. The reentrant geometry of nails creates large energy barrier for the wetting of the solid surface compared to straight pillars. We also study the effect of surface chemistry, pillar height, and inter-pillar spacing on the energy barrier and compare it with nails.« less

Spontaneous Spreading of a Droplet: The Role of Solid Continuity and Advancing Contact Angle.

PubMed

Jiang, Youhua; Sun, Yujin; Drelich, Jaroslaw W; Choi, Chang-Hwan

2018-05-01

Spontaneous spreading of a droplet on a solid surface is poorly understood from a macroscopic level down to a molecular level. Here, we investigate the effect of surface topography and wettability on spontaneous spreading of a water droplet. Spreading force is measured for a suspended droplet that minimizes interference of kinetic energy in the spontaneous spreading during its contact with solid surfaces of discontinuous (pillar) and continuous (pore) patterns with various shapes and dimensions. Results show that a droplet cannot spread spontaneously on pillared surfaces regardless of their shapes or dimensions because of the solid discontinuity. On the contrary, a droplet on pored surfaces can undergo spontaneous spreading whose force increases with a decrease in the advancing contact angle. Theoretical models based on both the system free energy and capillary force along the contact line validate the direct and universal dependency of the spontaneous spreading force on the advancing contact angle.

Rim-Differentiated C5-Symmetric Tiara-Pillar[5]arenes

PubMed Central

2017-01-01

The synthesis of “rim-differentiated” C5-symmetric pillar[5]arenes, whose two rims are decorated with different chemical functionalities, has remained a challenging task. This is due to the inherent statistical nature of the cyclization of 1,4-disubstituted alkoxybenzenes with different substituents, which leads to four constitutional isomers with only 1/16th being rim-differentiated. Herein, we report a “preoriented” synthetic protocol based on FeCl3-catalyzed cyclization of asymmetrically substituted 2,5-dialkoxybenzyl alcohols. This yields an unprecedented 55% selectivity of the C5-symmetric tiara-like pillar[5]arene isomer among four constitutional isomers. Based on this new method, a series of functionalizable tiara-pillar[5]arene derivatives with C5-symmetry was successfully synthesized, isolated, and fully characterized in the solid state. PMID:29220153

Stress reduction for pillar filled structures

DOEpatents

Nikolic, Rebecca J.; Conway, Adam; Shao, Qinghui; Voss, Lars; Cheung, Chin Li; Dar, Mushtaq A.

2015-09-01

According to one embodiment, an apparatus for detecting neutrons includes an array of pillars, wherein each of the pillars comprises a rounded cross sectional shape where the cross section is taken perpendicular to a longitudinal axis of the respective pillar, a cavity region between each of the pillars, and a neutron sensitive material located in each cavity region.

Ordered microporous layered lanthanide 1,3,5-benzenetriphosphonates pillared with cationic organic molecules.

PubMed

Araki, Takahiro; Kondo, Atsushi; Maeda, Kazuyuki

2015-04-13

Novel isomorphous pillared-layer-type crystalline lanthanide 1,3,5-benzenetriphosphonates were prepared with bpy and dbo as organic pillars (LnBP-bpy and LnBP-dbo; Ln: Ce, Pr, and Nd). Ab initio crystal structure solution using synchrotron X-ray powder diffraction data revealed that the organic pillars do not exist as neutral coordinating ligands but as cationic molecules. Especially the LnBP-dbo phases have ordered interlayer space filled with water molecules between the dbo pillars, and the interlayer water is successfully removed by heating under vacuum with slightly distorted but basically retained pillared layer structures. Microporosity of the materials is confirmed by adsorption of nitrogen, carbon dioxide, and hydrogen gases. Such microporous layered metal phosphonates pillared with cationic molecules should be unprecedented and should offer new strategies to design ordered microporous materials. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contact-angle hysteresis on periodic microtextured surfaces: Strongly corrugated liquid interfaces.

PubMed

Iliev, Stanimir; Pesheva, Nina

2016-06-01

We study numerically the shapes of a liquid meniscus in contact with ultrahydrophobic pillar surfaces in Cassie's wetting regime, when the surface is covered with identical and periodically distributed micropillars. Using the full capillary model we obtain the advancing and the receding equilibrium meniscus shapes when the cross-sections of the pillars are both of square and circular shapes, for a broad interval of pillar concentrations. The bending of the liquid interface in the area between the pillars is studied in the framework of the full capillary model and compared to the results of the heterogeneous approximation model. The contact angle hysteresis is obtained when the three-phase contact line is located on one row (block case) or several rows (kink case) of pillars. It is found that the contact angle hysteresis is proportional to the line fraction of the contact line on pillars tops in the block case and to the surface fraction for pillar concentrations 0.1-0.5 in the kink case. The contact angle hysteresis does not depend on the shape (circular or square) of the pillars cross-section. The expression for the proportionality of the receding contact angle to the line fraction [Raj et al., Langmuir 28, 15777 (2012)LANGD50743-746310.1021/la303070s] in the case of block depinning is theoretically substantiated through the capillary force, acting on the solid plate at the meniscus contact line.

Large-Area Fabrication of Droplet Pancake Bouncing Surface and Control of Bouncing State.

PubMed

Song, Jinlong; Gao, Mingqian; Zhao, Changlin; Lu, Yao; Huang, Liu; Liu, Xin; Carmalt, Claire J; Deng, Xu; Parkin, Ivan P

2017-09-26

Superhydrophobic pillar arrays, which can generate the droplet pancake bouncing phenomenon with reduced liquid-solid contact time, have huge application prospects in anti-icing of aircraft wings from freezing rain. However, the previously reported pillar arrays, suitable for obtaining pancake bouncing, have a diameter ≤100 μm and height-diameter ratio >10, which are difficult to fabricate over a large area. Here, we have systematically studied the influence of the dimension of the superhydrophobic pillar arrays on the bouncing dynamics of water droplets. We show that the typical pancake bouncing with 57.8% reduction in contact time with the surface was observed on the superhydrophobic pillar arrays with 1.05 mm diameter, 0.8 mm height, and 0.25 mm space. Such pillar arrays with millimeter diameter and <1 height-diameter ratio can be easily fabricated over large areas. Further, a simple replication-spraying method was developed for the large-area fabrication of the superhydrophobic pillar arrays to induce pancake bouncing. No sacrificial layer was needed to reduce the adhesion in the replication processes. Since the bouncing dynamics were rather sensitive to the space between the pillars, a method to control the contact time, bouncing shape, horizontal bouncing direction, and reversible switch between pancake bouncing and conventional bouncing was realized by adjusting the inclination angle of the shape memory polymer pillars.

Numerical simulation of quantum efficiency and surface recombination in HgCdTe IR photon-trapping structures

NASA Astrophysics Data System (ADS)

Schuster, Jonathan; Bellotti, Enrico

2013-06-01

We have investigated the quantum effiency in HgCdTe photovoltaic pixel arrays employing a photon-trapping structure realized with a periodic array of pillars intended to provide broadband operation. We have found that the quantum efficiency depends heavily on the passivation of the pillar surface. Pillars passivated with anodicoxide have a large fixed positive charge on the pillar surface. We use our three-dimensional numerical simulation model to study the effect of surface charge and surface recombination velocity on the exterior of the pillars. We then evaluate the quantum efficiency of this structure subject to different surface conditions. We have found that by themselves, the surface charge and surface recombination are detrimental to the quantum efficiency but the quantum efficiency is recovered when both phenomena are present. We will discuss the effects of these phenomena and the trade offs that exist between the two.

The Pillars of Creation revisited with MUSE: gas kinematics and high-mass stellar feedback traced by optical spectroscopy

NASA Astrophysics Data System (ADS)

McLeod, A. F.; Dale, J. E.; Ginsburg, A.; Ercolano, B.; Gritschneder, M.; Ramsay, S.; Testi, L.

2015-06-01

Integral field unit (IFU) data of the iconic Pillars of Creation in M16 are presented. The ionization structure of the pillars was studied in great detail over almost the entire visible wavelength range, and maps of the relevant physical parameters, e.g. extinction, electron density, electron temperature, line-of-sight velocity of the ionized and neutral gas are shown. In agreement with previous authors, we find that the pillar tips are being ionized and photoevaporated by the massive members of the nearby cluster NGC 6611. They display a stratified ionization structure where the emission lines peak in a descending order according to their ionization energies. The IFU data allowed us to analyse the kinematics of the photoevaporative flow in terms of the stratified ionization structure, and we find that, in agreement with simulations, the photoevaporative flow is traced by a blueshift in the position-velocity profile. The gas kinematics and ionization structure have allowed us to produce a sketch of the 3D geometry of the Pillars, positioning the pillars with respect to the ionizing cluster stars. We use a novel method to detect a previously unknown bipolar outflow at the tip of the middle pillar and suggest that it has an embedded protostar as its driving source. Furthermore we identify a candidate outflow in the leftmost pillar. With the derived physical parameters and ionic abundances, we estimate a mass-loss rate due to the photoevaporative flow of 70 M⊙ Myr-1 which yields an expected lifetime of approximately 3 Myr.

Gallium nitride heterostructures on 3D structured silicon.

PubMed

Fündling, Sönke; Sökmen, Unsal; Peiner, Erwin; Weimann, Thomas; Hinze, Peter; Jahn, Uwe; Trampert, Achim; Riechert, Henning; Bakin, Andrey; Wehmann, Hergo-Heinrich; Waag, Andreas

2008-10-08

We investigated GaN-based heterostructures grown on three-dimensionally patterned Si(111) substrates by metal organic vapour phase epitaxy, with the goal of fabricating well controlled high quality, defect reduced GaN-based nanoLEDs. The high aspect ratios of such pillars minimize the influence of the lattice mismatched substrate and improve the material quality. In contrast to other approaches, we employed deep etched silicon substrates to achieve a controlled pillar growth. For that a special low temperature inductively coupled plasma etching process has been developed. InGaN/GaN multi-quantum-well structures have been incorporated into the pillars. We found a pronounced dependence of the morphology of the GaN structures on the size and pitch of the pillars. Spatially resolved optical properties of the structures are analysed by cathodoluminescence.

Wetting transitions on patterned surfaces with diffuse interaction potentials embedded in a Young-Laplace formulation

NASA Astrophysics Data System (ADS)

Pashos, G.; Kokkoris, G.; Papathanasiou, A. G.; Boudouvis, A. G.

2016-01-01

The Minimum Energy Paths (MEPs) of wetting transitions on pillared surfaces are computed with the Young-Laplace equation, augmented with a pressure term that accounts for liquid-solid interactions. The interactions are smoothed over a short range from the solid phase, therefore facilitating the numerical solution of problems concerning wetting on complex surface patterns. The patterns may include abrupt geometric features, e.g., arrays of rectangular pillars, where the application of the unmodified Young-Laplace is not practical. The MEPs are obtained by coupling the augmented Young-Laplace with the modified string method from which the energy barriers of wetting transitions are eventually extracted. We demonstrate the method on a wetting transition that is associated with the breakdown of superhydrophobic behavior, i.e., the transition from the Cassie-Baxter state to the Wenzel state, taking place on a superhydrophobic pillared surface. The computed energy barriers quantify the resistance of the system to these transitions and therefore, they can be used to evaluate superhydrophobic performance or provide guidelines for optimal pattern design.

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

Nekoogar, F; Dowla, F; Wang, T

Recent advancements in the ultra-wide band Radio Frequency Identification (RFID) technology and solid state pillar type neutron detectors have enabled us to move forward in combining both technologies for advanced neutron monitoring. The LLNL RFID tag is totally passive and will operate indefinitely without the need for batteries. The tag is compact, can be directly mounted on metal, and has high performance in dense and cluttered environments. The LLNL coin-sized pillar solid state neutron detector has achieved a thermal neutron detection efficiency of 20% and neutron/gamma discrimination of 1E5. These performance values are comparable to a fieldable {sup 3}He basedmore » detector. In this paper we will discuss features about the two technologies and some potential applications for the advanced safeguarding of nuclear materials.« less

Micro-optical foundry: 3D lithography by freezing liquid instabilities at nanoscale

NASA Astrophysics Data System (ADS)

Grilli, S.; Coppola, S.; Vespini, V.; Merola, F.; Finizio, A.; Ferraro, P.

2012-06-01

The pyroelectric functionality of a Lithium Niobate (LN) substrate is used for non-contact manipulation of polymeric material. In this work we introduced a novel approach for fabricating a wide variety of soft solid-like microstructures, thus leading to a new concept in 3D lithography. A relatively easy to accomplish technique has been demonstrated for curing different transient stages of polymer fluids by rapid cross-linking of PDMS. The method is twofold innovative thanks to the electrode-less configuration and to the rapid formation of a wide variety of 3D solid-like structures by exploiting polymer instabilities. This new and unique technique is named "pyro-electrohydrodynamic (PEHD) lithography", meaning the generation of structures by using forces produced by electric fields generated by the pyroelectric effect. The fabrication of polymer wires, needles, pillars, cones, or microspheres is reported, and practical proofs of their use in photonics are presented.

Scaled Eagle Nebula Experiments on NIF

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

Pound, Marc W.

We performed scaled laboratory experiments at the National Ignition Facility laser to assess models for the creation of pillar structures in star-forming clouds of molecular hydrogen, in particular the famous Pillars of the Eagle Nebula. Because pillars typically point towards nearby bright ultraviolet stars, sustained directional illumination appears to be critical to pillar formation. The experiments mock up illumination from a cluster of ultraviolet-emitting stars, using a novel long duration (30--60 ns), directional, laser-driven x-ray source consisting of multiple radiation cavities illuminated in series. Our pillar models are assessed using the morphology of the Eagle Pillars observed with the Hubblemore » Space Telescope, and measurements of column density and velocity in Eagle Pillar II obtained at the BIMA and CARMA millimeter wave facilities. In the first experiments we assess a shielding model for pillar formation. The experimental data suggest that a shielding pillar can match the observed morphology of Eagle Pillar II, and the observed Pillar II column density and velocity, if augmented by late time cometary growth.« less

Method to planarize three-dimensional structures to enable conformal electrodes

DOEpatents

Nikolic, Rebecca J; Conway, Adam M; Graff, Robert T; Reinhardt, Catherine; Voss, Lars F; Shao, Qinghui

2012-11-20

Methods for fabricating three-dimensional PIN structures having conformal electrodes are provided, as well as the structures themselves. The structures include a first layer and an array of pillars with cavity regions between the pillars. A first end of each pillar is in contact with the first layer. A segment is formed on the second end of each pillar. The cavity regions are filled with a fill material, which may be a functional material such as a neutron sensitive material. The fill material covers each segment. A portion of the fill material is etched back to produce an exposed portion of the segment. A first electrode is deposited onto the fill material and each exposed segment, thereby forming a conductive layer that provides a common contact to each the exposed segment. A second electrode is deposited onto the first layer.

Inducing morphological changes in lipid bilayer membranes with microfabricated substrates

NASA Astrophysics Data System (ADS)

Liu, Fangjie; Collins, Liam F.; Ashkar, Rana; Heberle, Frederick A.; Srijanto, Bernadeta R.; Collier, C. Patrick

2016-11-01

Lateral organization of lipids and proteins into distinct domains and anchoring to a cytoskeleton are two important strategies employed by biological membranes to carry out many cellular functions. However, these interactions are difficult to emulate with model systems. Here we use the physical architecture of substrates consisting of arrays of micropillars to systematically control the behavior of supported lipid bilayers - an important step in engineering model lipid membrane systems with well-defined functionalities. Competition between attractive interactions of supported lipid bilayers with the underlying substrate versus the energy cost associated with membrane bending at pillar edges can be systematically investigated as functions of pillar height and pitch, chemical functionalization of the microstructured substrate, and the type of unilamellar vesicles used for assembling the supported bilayer. Confocal fluorescent imaging and AFM measurements highlight correlations that exist between topological and mechanical properties of lipid bilayers and lateral lipid mobility in these confined environments. This study provides a baseline for future investigations into lipid domain reorganization on structured solid surfaces and scaffolds for cell growth.

Physicochemical of pillared clays prepared by several metal oxides

NASA Astrophysics Data System (ADS)

Rinaldi, Nino; Kristiani, Anis

2017-03-01

Natural clays could be modified by the pillarization method, called as Pillared Clays (PILCs). PILCs have been known as porous materials that can be used for many applications, one of the fields is catalysis. PILCs as two dimensional materials are interesting because their structures and textural properties can be controlled by using a metal oxide as the pillar. Different metal oxide used as the pillar causes different properties results of pillared clays. Usually, natural smectite clays/bentonites are used as a raw material. Therefore, a series of bentonite pillared by metal oxides was prepared through pillarization method. Variation of metals pillared into bentonite are aluminium, chromium, zirconium, and ferro. The physicochemical properties of catalysts were characterized by using X-ray Diffraction (XRD), Thermo Gravimetric Analysis (TGA), Brunauer-Emmett-Teller (BET) and Barret-Joyner-Halenda (BJH) analysis, and Fourier transform infrared spectroscopy (FTIR) measurement. Noteworthy characterization results showed that different metals pillared into bentonite affected physical and chemical properties, i.e. basal spacing, surface area, pore size distribution, thermal stability and acidity.

Glass Masonry - Experimental Verification of Bed Joint under Shear

NASA Astrophysics Data System (ADS)

Fíla, J.; Eliášová, M.; Sokol, Z.

2017-10-01

Glass is considered as a traditional material for building industry but was mostly used for glazing of the windows. At present, glass is an integral part of contemporary architecture where glass structural elements such as beams, stairs, railing ribs or columns became popular in the last two decades. However, using glass as structural material started at the beginning of 20th century, when masonry from hollow glass blocks were used. Using solid glass brick is very rare and only a few structures with solid glass bricks walls have been built in the last years. Pillars and walls made from solid glass bricks are mainly loaded by compression and/or bending from the eccentricity of vertical load or wind load. Due to high compressive strength of glass, the limiting factor of the glass masonry is the joint between the glass bricks as the smooth surface requires another type of mortar / glue compared to traditional masonry. Shear resistance and failure modes of brick bed joint was determined during series of tests using various mortars, two types of surface treatment and different thickness of the mortar joint. Shear tests were completed by small scale tests for mortar - determination of flexural and compressive strength of hardened mortar.

Cuttlebone-like V2O5 Nanofibre Scaffolds - Advances in Structuring Cellular Solids.

PubMed

Knöller, Andrea; Runčevski, Tomče; Dinnebier, Robert E; Bill, Joachim; Burghard, Zaklina

2017-02-20

The synthesis of ceramic materials combining high porosity and permeability with good mechanical stability is challenging, as optimising the latter requires compromises regarding the first two properties. Nonetheless, significant progress can be made in this direction by taking advantage of the structural design principles evolved by nature. Natural cellular solids achieve good mechanical stability via a defined hierarchical organisation of the building blocks they are composed of. Here, we report the first synthetic, ceramic-based scaffold whose architecture closely mimics that of cuttlebone -a structural biomaterial whose porosity exceeds that of most other natural cellular solids, whilst preserving an excellent mechanical strength. The nanostructured, single-component scaffold, obtained by ice-templated assembly of V 2 O 5 nanofibres, features a highly sophisticated and elaborate architecture of equally spaced lamellas, which are regularly connected by pillars as lamella support. It displays an unprecedented porosity of 99.8 %, complemented by an enhanced mechanical stability. This novel bioinspired, functional material not only displays mechanical characteristics similar to natural cuttlebone, but the multifunctionality of the V 2 O 5 nanofibres also renders possible applications, including catalysts, sensors and electrodes for energy storage.

Cuttlebone-like V2O5 Nanofibre Scaffolds - Advances in Structuring Cellular Solids

NASA Astrophysics Data System (ADS)

Knöller, Andrea; Runčevski, Tomče; Dinnebier, Robert E.; Bill, Joachim; Burghard, Zaklina

2017-02-01

The synthesis of ceramic materials combining high porosity and permeability with good mechanical stability is challenging, as optimising the latter requires compromises regarding the first two properties. Nonetheless, significant progress can be made in this direction by taking advantage of the structural design principles evolved by nature. Natural cellular solids achieve good mechanical stability via a defined hierarchical organisation of the building blocks they are composed of. Here, we report the first synthetic, ceramic-based scaffold whose architecture closely mimics that of cuttlebone -a structural biomaterial whose porosity exceeds that of most other natural cellular solids, whilst preserving an excellent mechanical strength. The nanostructured, single-component scaffold, obtained by ice-templated assembly of V2O5 nanofibres, features a highly sophisticated and elaborate architecture of equally spaced lamellas, which are regularly connected by pillars as lamella support. It displays an unprecedented porosity of 99.8 %, complemented by an enhanced mechanical stability. This novel bioinspired, functional material not only displays mechanical characteristics similar to natural cuttlebone, but the multifunctionality of the V2O5 nanofibres also renders possible applications, including catalysts, sensors and electrodes for energy storage.

Capacitance reduction for pillar structured devices

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

Shao, Qinghui; Conway, Adam; Nikolic, Rebecca J.

2017-05-09

In one embodiment, an apparatus includes: a first layer including a n+ dopant or p+ dopant; an intrinsic layer formed above the first layer, the intrinsic layer including a planar portion and pillars extending above the planar portion, cavity regions being defined between the pillars; and a second layer deposited on a periphery of the pillars thereby forming coated pillars, the second layer being substantially absent on the planar portion of the intrinsic layer between the coated pillars. The second layer includes an n+ dopant when the first layer includes a p+ dopant. The second layer includes a p+ dopantmore » when the first layer includes an n+ dopant. The apparatus includes a neutron sensitive material deposited between the coated pillars and above the planar portion of the intrinsic layer. In additional embodiments, an upper portion of each of the pillars includes a same type of dopant as the second layer.« less

Effects of PCB Pad Metal Finishes on the Cu-Pillar/Sn-Ag Micro Bump Joint Reliability of Chip-on-Board (COB) Assembly

NASA Astrophysics Data System (ADS)

Kim, Youngsoon; Lee, Seyong; Shin, Ji-won; Paik, Kyung-Wook

2016-06-01

While solder bumps have been used as the bump structure to form the interconnection during the last few decades, the continuing scaling down of devices has led to a change in the bump structure to Cu-pillar/Sn-Ag micro-bumps. Cu-pillar/Sn-Ag micro-bump interconnections differ from conventional solder bump interconnections in terms of their assembly processing and reliability. A thermo-compression bonding method with pre-applied b-stage non-conductive films has been adopted to form solder joints between Cu pillar/Sn-Ag micro bumps and printed circuit board vehicles, using various pad metal finishes. As a result, various interfacial inter-metallic compounds (IMCs) reactions and stress concentrations occur at the Cu pillar/Sn-Ag micro bumps joints. Therefore, it is necessary to investigate the influence of pad metal finishes on the structural reliability of fine pitch Cu pillar/Sn-Ag micro bumps flip chip packaging. In this study, four different pad surface finishes (Thin Ni ENEPIG, OSP, ENEPIG, ENIG) were evaluated in terms of their interconnection reliability by thermal cycle (T/C) test up to 2000 cycles at temperatures ranging from -55°C to 125°C and high-temperature storage test up to 1000 h at 150°C. The contact resistances of the Cu pillar/Sn-Ag micro bump showed significant differences after the T/C reliability test in the following order: thin Ni ENEPIG > OSP > ENEPIG where the thin Ni ENEPIG pad metal finish provided the best Cu pillar/Sn-Ag micro bump interconnection in terms of bump joint reliability. Various IMCs formed between the bump joint areas can account for the main failure mechanism.

Ultra-low specific on-resistance 700V LDMOS with a buried super junction layer

NASA Astrophysics Data System (ADS)

Wang, Hai-Shi; Li, Zhi-you; Li, Ke; Qiao, Ming

2018-01-01

An ultra-low specific on-resistance 700 V lateral double-diffused MOSFET (LDMOS) with a buried super junction (BSJ) layer is proposed. [1-9] Buried P-pillars in the LDMOS can be depleted by neighboring N-pillars, overlying and underlying N-drift regions simultaneously, thus allowing a higher doping concentration. Consequently, the doping concentration of either the N-drift regions or N-pillars, or both, may also be increased therewith to compensate the surplus charges in the P-pillars. Compared with conventional surface super junction (SSJ) LDMOS, in which the super junction layer is implemented at the upper surface of the drift region, and P-pillars can only be depleted by the adjacent N-pillars and the N-drift regions beneath, the proposed novel LDMOS structure may have a lower specific on-resistance (Ron,sp) while maintain the same breakdown voltage (BV). Simulation results indicate that the Ron,sp of the novel structure is only 80.5 mΩ cm2 with a high BV of 750 V, which is reduced by 17% in comparison with the Ron,sp of a conventional SSJ LDMOS.

Superlensing effect for surface acoustic waves in a pillar-based phononic crystal with negative refractive index

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

Addouche, Mahmoud, E-mail: mamoud.addouche@femto-st.fr; Al-Lethawe, Mohammed A., E-mail: mohammed.abdulridha@femto-st.fr; Choujaa, Abdelkrim, E-mail: achoujaa@femto-st.fr

2014-07-14

We demonstrate super resolution imaging for surface acoustic waves using a phononic structure displaying negative refractive index. This phononic structure is made of a monolithic square lattice of cylindrical pillars standing on a semi-infinite medium. The pillars act as acoustic resonator and induce a surface propagating wave with unusual dispersion. We found, under specific geometrical parameters, one propagating mode that exhibits negative refraction effect with negative effective index close to −1. Furthermore, a flat lens with finite number of pillars is designed to allow the focusing of an acoustic point source into an image with a resolution of (λ)/3 ,more » overcoming the Rayleigh diffraction limit.« less

{pi}-{pi} Interactions and magnetic properties in a series of hybrid inorganic-organic crystals

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

Gonzalez, M.; Lemus-Santana, A.A.; Rodriguez-Hernandez, J.

The series of hybrid inorganic-organic solids T(Im){sub 2}[Ni(CN){sub 4}] with T=Fe, Co, Ni and Im=imidazole were prepared by soft chemical routes from aqueous solutions of the involved building units: imidazole, T{sup 2+} metal and the [Ni(CN){sub 4}]{sup 2-} anionic block. The obtained samples were characterized from infrared and UV-vis spectroscopies, and thermogravimetric, X-ray diffraction and magnetic measurements. Anhydrous solids which crystallize with a monoclinic unit cell, in the I2/a space group with four formula units per cell (Z=4) were obtained. Their crystal structure was solved ab initio from the recorded X-ray powder patterns and then refined by the Rietveld method.more » The metal T is found with octahedral coordination to four N ends of CN groups and two imidazole molecules while the inner Ni atom preserves its planar coordination. The system of layers remains stacked in an ordered 3D structure through dipole-dipole and {pi}-{pi} interactions between imidazole rings from neighboring layers. In this way, a pillared structure is achieved without requiring the coordination of both nitrogen atoms from imidazole ring. The recorded magnetic data indicate the occurrence of a predominant ferromagnetic interaction at low temperature for Co and Ni but not for Fe. Such magnetic ordering is more favorable for Ni with transition temperature of 14.67 K, which was ascribed to the relatively high polarizing power for this metal. Within the considered T metals, to nickel the highest electron-withdrawing ability corresponds and this leads to an increase for the metal-ligand electron clouds overlapping and to a stronger {pi}-{pi} attractive interaction, two factors that result into a higher magnetic ordering temperature. - Graphical Abstract: Magnetic ordering through the {pi}-{pi} interaction between the imidazole rings. Highlights: Black-Right-Pointing-Pointer Hybrid inorganic-organic solids. Black-Right-Pointing-Pointer Hybrid inorganic-organic molecular based magnets. Black-Right-Pointing-Pointer Ferromagnetic interaction through {pi}-{pi} stacking of imidazole rings. Black-Right-Pointing-Pointer Organic pillars formed through {pi}-{pi} stacking.« less

Data supporting attempted caveolae-mediated phagocytosis of surface-fixed micro-pillars by human osteoblasts.

PubMed

Moerke, Caroline; Mueller, Petra; Nebe, Barbara

2016-06-01

The provided data contains the phagocytic interaction of human MG-63 osteoblasts with micro-particles 6 µm in size as well as geometric micro-pillared topography with micro-pillar sizes 5 µm of length, width, height and spacing respectively related to the research article entitled "Attempted caveolae-mediated phagocytosis of surface-fixed micro-pillars by human osteoblasts" in the Biomaterials journal. [1] Micro-particle treatment was used as positive control triggering phagocytosis by the osteoblasts. Caveolin-1 (Cav-1) as major structural component of caveolae [2] plays an important role in the phagocytic process of micro-particles and -pillars. Data related to the experiments in [1] with siRNA-mediated knockdown are presented here as well as micro-particle control experiments, tubulin analysis on the micro-pillared topography and initial cell interaction with the micro-pillars.

Hierarchical structure observation and nanoindentation size effect characterization for a limnetic shell

NASA Astrophysics Data System (ADS)

Song, Jingru; Fan, Cuncai; Ma, Hansong; Wei, Yueguang

2015-06-01

In the present research, hierarchical structure observation and mechanical property characterization for a type of biomaterial are carried out. The investigated biomaterial is Hyriopsis cumingii, a typical limnetic shell, which consists of two different structural layers, a prismatic "pillar" structure and a nacreous "brick and mortar" structure. The prismatic layer looks like a "pillar forest" with variation-section pillars sized on the order of several tens of microns. The nacreous material looks like a "brick wall" with bricks sized on the order of several microns. Both pillars and bricks are composed of nanoparticles. The mechanical properties of the hierarchical biomaterial are measured by using the nanoindentation test. Hardness and modulus are measured for both the nacre layer and the prismatic layer, respectively. The nanoindentation size effects for the hierarchical structural materials are investigated experimentally. The results show that the prismatic nanostructured material has a higher stiffness and hardness than the nacre nanostructured material. In addition, the nanoindentation size effects for the hierarchical structural materials are described theoretically, by using the trans-scale mechanics theory considering both strain gradient effect and the surface/interface effect. The modeling results are consistent with experimental ones.

Cu Pillar Low Temperature Bonding and Interconnection Technology of for 3D RF Microsystem

NASA Astrophysics Data System (ADS)

Shi, G. X.; Qian, K. Q.; Huang, M.; Yu, Y. W.; Zhu, J.

2018-03-01

In this paper 3D interconnects technologies used Cu pillars are discussed with respect to RF microsystem. While 2.5D Si interposer and 3D packaging seem to rely to cu pillars for the coming years, RF microsystem used the heterogeneous chip such as GaAs integration with Si interposers should be at low temperature. The pillars were constituted by Cu (2 micron) -Ni (2 micron) -Cu (3 micron) -Sn (1 micron) multilayer metal and total height is 8 micron on the front-side of the wafer by using electroplating. The wafer backside Cu pillar is obtained by temporary bonding, thinning and silicon surface etching. The RF interposers are stacked by Cu-Sn eutectic bonding at 260 °C. Analyzed the reliability of different pillar bonding structure.

Modeling the interactions between compliant microcapsules and pillars in microchannels

NASA Astrophysics Data System (ADS)

Zhu, Guangdong; Alexeev, Alexander; Kumacheva, Eugenia; Balazs, Anna C.

2007-07-01

Using a computational model, we investigate the motion of microcapsules inside a microchannel that encompasses a narrow constriction. The microcapsules are composed of a compliant, elastic shell and an encapsulated fluid; these fluid-filled shells model synthetic polymeric microcapsules or biological cells (e.g., leukocytes). Driven by an imposed flow, the capsules are propelled along the microchannel and through the constricted region, which is formed by two pillars that lie in registry, extending from the top and bottom walls of the channels. The tops of these pillars (facing into the microchannel) are modified to exhibit either a neutral or an attractive interaction with the microcapsules. The pillars (and constriction) model topological features that can be introduced into microfluidic devices or the physical and chemical heterogeneities that are inherently present in biological vessels. To simulate the behavior of this complex system, we employ a hybrid method that integrates the lattice Boltzmann model (LBM) for fluid dynamics and the lattice spring model (LSM) for the micromechanics of elastic solids. Through this LBM/LSM technique, we probe how the capsule's stiffness and interaction with the pillars affect its passage through the chambers. The results yield guidelines for regulating the movement of microcarriers in microfluidic systems and provide insight into the flow properties of biological cells in capillaries.

Squeeze flow between a sphere and a textured wall

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

Chastel, T.; Mongruel, A., E-mail: anne.mongruel@upmc.fr

2016-02-15

The motion of a millimetric sphere, translating in a viscous fluid towards a wettable textured wall, is investigated experimentally. The textures consist of square arrays of cylindrical or square micro-pillars, the height, width, and spacing of which are varied, keeping the periodicity small compared to the sphere radius. An interferometric device is used to measure the sphere vertical displacement, for distances between the sphere and the base of the pillars smaller than 0.1 sphere radius, and with a resolution of 200 nm. At a given distance from the top of the pillars, the sphere velocity is found to be significantlymore » larger than the corresponding velocity for a smooth solid wall. A squeeze flow model of two adjacent fluid layers is developed in the lubrication approximation, one fluid layer having an effective viscosity that reflects the viscous dissipation through the array of pillars. The pressure field in the gap between the sphere and the textured surface is then used to obtain the drag force on the sphere and hence its velocity. Adjustment of the model to the velocity measurements yields the effective viscosity for a given texture. Finally, a correlation between the effective viscosity and the geometry of the pillar array is proposed.« less

Inertial effects on heat transfer in superhydrophobic microchannels

NASA Astrophysics Data System (ADS)

Cowley, Adam; Maynes, Daniel; Crockett, Julie; Iverson, Brian; BYU Fluids Team

2015-11-01

This work numerically studies the effects of inertia on thermal transport in superhydrophbic microchannels. An infinite parallel plate channel comprised of structured superhydrophbic walls is considered. The structure of the superhydrophobic surfaces consists of square pillars organized in a square array aligned with the flow direction. Laminar, fully developed flow is explored. The flow is assumed to be non-wetting and have an idealized flat meniscus. A shear-free, adiabatic boundary condition is used at the liquid/gas interface, while a no-slip, constant heat flux condition is used at the liquid/solid interface. A wide range of Peclet numbers, relative channel spacing distances, and relative pillar sizes are considered. Results are presented in terms of Poiseuille number, Nusselt number, hydrodynamic slip length, and temperature jump length. Interestingly, the thermal transport is varied only slightly by inertial effects for a wide range of parameters explored and compares well with other analytical and numerical work that assumed Stokes flow. It is only for very small relative channel spacing and large Peclet number that inertial effects exert significant influence. Overall, the heat transfer is reduced for the superhydrophbic channels in comparison to classic smooth walled channels. This research was supported by the National Science Foundation (NSF) - United States (Grant No. CBET-1235881).

Screening Hofmann Compounds as CO 2 Sorbents: Nontraditional Synthetic Route to Over 40 Different Pore-Functionalized and Flexible Pillared Cyanonickelates

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

Culp, Jeffrey T.; Madden, Catherine; Kauffman, Kristi

2013-04-15

A simple reaction scheme based on the heterogeneous intercalation of pillaring ligands (HIPLs) provides a convenient method for systematically tuning pore size, pore functionality, and network flexibility in an extended series of pillared cyanonickelates (PICNICs), commonly referred to as Hofmann compounds. The versatility of the approach is demonstrated through the preparation of over 40 different PICNICs containing pillar ligands ranging from 4 to 15 Å in length and modified with a wide range of functional groups, including fluoro, aldehyde, alkylamine, alkyl, aryl, trifluoromethyl, ester, nitro, ether, and nonmetalated 4,4'-bipyrimidine. The HIPL method involves reaction of a suspension of preformed polymericmore » sheets of powdered anhydrous nickel cyanide with an appropriate pillar ligand in refluxing organic solvent, resulting in the conversion of the planar [Ni{sub 2}(CN){sub 4}]{sub n} networks into polycrystalline three-dimensional porous frameworks containing the organic pillar ligand. Preliminary investigations indicate that the HIPL reaction is also amenable to forming Co(L)Ni(CN){sub 4}, Fe(L)Ni(CN){sub 4}, and Fe(L)Pd(CN){sub 4} networks. The materials show variable adsorption behavior for CO{sub 2} depending on the pillar length and pillar functionalization. Several compounds show structurally flexible behavior during the adsorption and desorption of CO{sub 2}. Interestingly, the newly discovered flexible compounds include two flexible Fe(L)Ni(CN){sub 4} derivatives that are structurally related to previously reported porous spin-crossover compounds. The preparations of 20 pillar ligands based on ring-functionalized 4,4'-dipyridyls, 1,4-bis(4-pyridyl)benzenes, and N-(4-pyridyl)isonicotinamides are also described.« less

Screening Hofmann Compounds as CO 2 Sorbents: Nontraditional Synthetic Route to Over 40 Different Pore-Functionalized and Flexible Pillared Cyanonickelates

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

Culp, Jeffrey T.; Madden, Catherine; Kauffman, Kristi

2013-04-15

A simple reaction scheme based on the heterogeneous intercalation of pillaring ligands (HIPLs) provides a convenient method for systematically tuning pore size, pore functionality, and network flexibility in an extended series of pillared cyanonickelates (PICNICs), commonly referred to as Hofmann compounds. The versatility of the approach is demonstrated through the preparation of over 40 different PICNICs containing pillar ligands ranging from ~4 to ~15 Å in length and modified with a wide range of functional groups, including fluoro, aldehyde, alkylamine, alkyl, aryl, trifluoromethyl, ester, nitro, ether, and nonmetalated 4,4'-bipyrimidine. The HIPL method involves reaction of a suspension of preformed polymericmore » sheets of powdered anhydrous nickel cyanide with an appropriate pillar ligand in refluxing organic solvent, resulting in the conversion of the planar [Ni{sub 2}(CN){sub 4}]{sub n} networks into polycrystalline three-dimensional porous frameworks containing the organic pillar ligand. Preliminary investigations indicate that the HIPL reaction is also amenable to forming Co(L)Ni(CN){sub 4}, Fe(L)Ni(CN){sub 4}, and Fe(L)Pd(CN){sub 4} networks. The materials show variable adsorption behavior for CO{sub 2} depending on the pillar length and pillar functionalization. Several compounds show structurally flexible behavior during the adsorption and desorption of CO{sub 2}. Interestingly, the newly discovered flexible compounds include two flexible Fe(L)Ni(CN){sub 4} derivatives that are structurally related to previously reported porous spin-crossover compounds. The preparations of 20 pillar ligands based on ring-functionalized 4,4'-dipyridyls, 1,4-bis(4- pyridyl)benzenes, and N-(4-pyridyl)isonicotinamides are also described.« less

Catalytic Wastewater Treatment Using Pillared Clays

NASA Astrophysics Data System (ADS)

Perathoner, Siglinda; Centi, Gabriele

After introduction on the use of solid catalysts in wastewater treatment technologies, particularly advanced oxidation processes (AOPs), this review discussed the use of pillared clay (PILC) materials in three applications: (i) wet air catalytic oxidation (WACO), (ii) wet hydrogen peroxide catalytic oxidation (WHPCO) on Cu-PILC and Fe-PILC, and (iii) behavior of Ti-PILC and Fe-PILC in the photocatalytic or photo-Fenton conversion of pollutants. Literature data are critically analyzed to evidence the main direction to further investigate, in particularly with reference to the possible practical application of these technologies to treat industrial, municipal, or agro-food production wastewater.

Peering Inside the Pillars of Creation

NASA Astrophysics Data System (ADS)

Kohler, Susanna

2018-06-01

On 1 April 1995, Hubble captured one of its most well-known images: a stunning photo of towering features known as the Pillars of Creation, located in the Eagle Nebula just 7,000 light-years away. A new study explores how these iconic columns are influenced by the magnetic fields within them.Pillars from ShocksAn illustrative figure of the BISTRO magnetic-field vectors observed in the Pillars of Creation, overlaid on a Hubble composite of the pillars. [Pattle et al. 2018]In the Hubble image, we see the result of young, hot stars that have driven a photoionization shock into the cloud around them, forming complex structures in the dense gas at the shock interfaces. These structures in this case, dense columns of neutral gas and dust are then bombarded with hot radiation from the young stars, giving the structures a misty, ethereal look as they photoevaporate.Though we have a rough picture, the specifics of how the Pillars of Creation were formed and how they evolve in this harsh radiation environment arent yet fully understood. In particular, the role of magnetic fields in shaping and sustaining these pillars is poorly constrained, both observationally and theoretically.To address this problem, a team of scientists led by Kate Pattle (University of Central Lancashire, UK and National Tsing Hua University, Taiwan), has now made the first direct observations of the magnetic-field morphology within the Pillars of Creation.The authors proposed formation scenario: a) an ionization front approaches an overdensity in the molecular gas, b) the front is slowed at the overdensity, causing the magnetic field lines to bend, c) the compressed magnetic field supports the pillar against radial collapse, but cant support against longitudinal erosion. [Adapted from Pattle et al. 2018]Observing FieldsPattle and collaborators imaged the pillars as a part of the B-Fields in Star-Forming Region Observations (BISTRO) project, which uses a camera and polarimeter mounted on the James Clerk Maxwell Telescope in Hawaii. The high-resolution, submillimeter-wavelength polarimetric observations allowed the team to measure the orientations of the magnetic fields within the pillars.Pattle and collaborators found that the magnetic fields inside the Pillars of Creation are actually quite organized: they generally run along the length of the pillars, perpendicular to and decoupled from the field in the surrounding cloud. The authors use their observations to estimate the strength of the fields: roughly 170320 G in the pillars.Magnetic SupportWhat do these results tell us? First, the strength of the fields is consistent with a formation scenario in which very weakly magnetized gas was compressed to form columns. The authors propose that the Pillars of Creation were formed when an ionization front driven by radiation from nearby young, hot stars encountered a dense clump as it moved through the cloud of molecular gas. The overdensity slowed the front, causing the magnetic field to bend as the surrounding gas moved. The compressed magnetic field then supported the resulting column from collapse.Pattle and collaborators argue that the magnetic fields in the Pillars of Creation are supporting the pillars radially against collapse even now. They may also be preventing the pillar ends from breaking off into disconnected clumps known as cometary globules, a process that could eventually disintegrate the pillars.So whats BISTRO up to now? The project is continuing to survey magnetic fields in the dense gas of other nearby high-mass star-forming regions. This may help confirm the results found for the Pillars of Creation, bringing us another step closer to understanding how magnetic fields influence the some of the striking features that Hubble and other telescopes have revealed in our astronomical backyard.CitationKate Pattle et al 2018 ApJL 860 L6. doi:10.3847/2041-8213/aac771

Determination of adsorptive and catalytic properties of copper, silver and iron contain titanium-pillared bentonite for the removal bisphenol A from aqueous solution

NASA Astrophysics Data System (ADS)

Tomul, Fatma; Turgut Basoglu, Funda; Canbay, Hale

2016-01-01

Ti-pillared bentonite, Cu, Ag and Fe modified Ti-pillared bentonite and Cu/Ti- and Fe/Ti-mixed pillared bentonite were synthesized using different titanium sources by direct synthesis or by modification after synthesis. The effects of synthesis conditions on the surface characteristics, pore structure and acidity of the pillared bentonites were investigated by SEM⿿EDS, XPS, XRD, N2-adsorption/desorption and FTIR analyses before and after ammonia adsorption. The results of EDS, XPS and XRD analysis confirmed that titanium, copper, silver and iron were incorporated into the bentonite structure. In the XRD patterns, the formation of delaminated structure reflecting the non-parallel distribution of the bentonite layers by pillaring with Ti, Cu/Ti and Fe/Ti-pillars was observed. XPS spectra indicated the presence of TiO2, CuO, Ag and Ag2O and Fe2O3 species depending on the source of active metals in the synthesized samples. In the FTIR spectra, an increase in the Bronsted/Lewis peak intensity was observed with the loading of copper and iron, whereas a decrease in Lewis and Bronsted acidities was observed with incorporation of silver. Adsorption studies indicated that the adsorption capacity of the sample synthesized using titanium (IV) propoxide and incorporating iron to the structure by ion exchange (Fe-PTi-PILC) were higher than those in other samples. The adsorption of BPA (bisphenol A) by all tested samples was found to fit the Langmuir isotherm. In the catalytic wet peroxide oxidation (CWPO) over PTi-PILC (prepared by titanium (IV) propoxide), Fe-PTi-PILC and Cu-PTi-PILC (prepared by copper impregnated Ti-pillared bentonite) samples, BPA values close to complete conversion were achieved within 30 min at 25 °C, pH 4 and 5 g/L mcat. CWPO results showed that increasement of pH causes a decrease the rate of oxidation. On the other hand, by the time catalyst and BPA concentration is increased, the rate of oxidation is increased as well.

Roof-crush strength improvement using rigid polyurethane foam

NASA Astrophysics Data System (ADS)

Lilley, K.; Mani, A.

1998-08-01

Recent bending tests show the effectiveness of rigid, polyurethane foam in improving the strength of automotive body structures. By using foam, it is possible to reduce pillar sections, and to reduce thicknesses or eliminate reinforcements inside the pillars, and thereby offset the mass increase due to the foam filling. Further tests showed that utilizing the foam filling in a B-pillar to reduce section size can save ~20 mm that could be utilized to add energy absorbing structures in order to meet the new interior head impact requirements specified by the federal motor vehicle safety standards (FMVSS) 201 Head Impact Protection upgrade.

Fabrication and Characterization of Nanopillars for Silicon-Based Thermoelectrics

NASA Astrophysics Data System (ADS)

Stranz, A.; Sökmen, Ü.; Wehmann, H.-H.; Waag, A.; Peiner, E.

2010-09-01

Si-based nanopillars of various sizes were fabricated by lateral structuring using anisotropic etching and thermal oxidation. We obtained pillars of diameter <500 nm, about 25 μm in height, with an aspect ratio of more than 50. The distance between pillars was varied from 500 nm to 10 μm. Besides the fabrication and structural characterization of silicon nanopillars, implementation of adequate metrology for measuring single pillars is described. Commercial tungsten probes, self-made gold probes, and piezoresistive silicon cantilever probes were used for measurements of nanopillars in a scanning electron microscope (SEM) equipped with nanomanipulators.

Tailoring the strain in Si nano-structures for defect-free epitaxial Ge over growth.

PubMed

Zaumseil, P; Yamamoto, Y; Schubert, M A; Capellini, G; Skibitzki, O; Zoellner, M H; Schroeder, T

2015-09-04

We investigate the structural properties and strain state of Ge nano-structures selectively grown on Si pillars of about 60 nm diameter with different SiGe buffer layers. A matrix of TEOS SiO2 surrounding the Si nano-pillars causes a tensile strain in the top part at the growth temperature of the buffer that reduces the misfit and supports defect-free initial growth. Elastic relaxation plays the dominant role in the further increase of the buffer thickness and subsequent Ge deposition. This method leads to Ge nanostructures on Si that are free from misfit dislocations and other structural defects, which is not the case for direct Ge deposition on these pillar structures. The Ge content of the SiGe buffer is thereby not a critical parameter; it may vary over a relatively wide range.

Reconsideration of Si pillar thermal oxidation mechanism

NASA Astrophysics Data System (ADS)

Kageshima, Hiroyuki; Shiraishi, Kenji; Endoh, Tetsuo

2018-06-01

The mechanism of Si pillar thermal oxidation is considered. The Si emission is discussed in the oxidation of three-dimensional structures, which must be fundamentally important to understand the oxidation mechanism. It is confirmed that the Si emission is enhanced in the three-dimensional structures by the geometrical and stress effects. The larger effect is expected for Si spheres rather than for Si pillars. More enhanced Si emission can be expected for the smaller spheres. Then the mechanism of Si missing and the effect of Si emission are also discussed. The oxide viscous flow mechanism is the promising candidate to explain the Si missing, because the oxide viscosity could be reduced by the SiO incorporation and the compressive stress. The geometrical effect induces the viscosity gradient, which is important to induce the Si missing. Interplay of the emitted SiO and the accumulated stress is the key in Si pillar oxidation. Careful approaches are suggested for the oxidation of three-dimensional structures.

NIF Discovery Science Eagle Nebula

NASA Astrophysics Data System (ADS)

Kane, Jave; Martinez, David; Pound, Marc; Heeter, Robert; Casner, Alexis; Villette, Bruno; Mancini, Roberto

2017-10-01

The University of Maryland and and LLNL are investigating the origin and dynamics of the famous Pillars of the Eagle Nebula and similar parsec-scale structures at the boundaries of HII regions in molecular hydrogen clouds. The National Ignition Facility (NIF) Discovery Science program Eagle Nebula has performed NIF shots to study models of pillar formation. The shots feature a new long-duration x-ray source, in which multiple hohlraums mimicking a cluster of stars are driven with UV light in series for 10 to 15 ns each to create a 30 to 60 ns output x-ray pulse. The source generates deeply nonlinear hydrodynamics in the Eagle science package, a structure of dense plastic and foam mocking up a molecular cloud containing a dense core. Omega EP and NIF shots have validated the source concept, showing that earlier hohlraums do not compromise later ones by preheat or by ejecting ablated plumes that deflect later beams. The NIF shots generated radiographs of shadowing-model pillars, and also showed evidence that cometary structures can be generated. The velocity and column density profiles of the NIF shadowing and cometary pillars have been compared with observations of the Eagle Pillars made at the millimeter-wave BIMA and CARMA observatories. Prepared by LLNL under Contract DE-AC52-07NA27344.

Measurement of locally resonant band gaps in a surface phononic crystal with inverted conical pillars

NASA Astrophysics Data System (ADS)

Hsu, Jin-Chen; Lin, Fan-Shun

2018-07-01

In this paper, we numerically and experimentally study locally resonant (LR) band gaps for surface acoustic waves (SAWs) in a honeycomb array of inverted conical pillars grown on the surface of a 128°YX lithium-niobate substrate. We show that the inverted conical pillars can be used to generate lower LR band gaps below the sound cone. This lowering effect is caused by the increase in the effective pillar mass without increasing the effective stiffness. We employ the finite-element method to calculate the LR band gaps and wideband slanted-finger interdigital transducers to measure the transmission of SAWs. Numerical results show that SAWs are prohibited from propagating through the structure in the lowered LR band gaps. Obvious LR band-gap lowering is observed in the experimental result of a surface phononic crystal with a honeycomb array of inverted conical pillars. The results enable enhanced control over the phononic metamaterial and surface structures, which may have applications in low-frequency waveguiding, acoustic isolation, acoustic absorbers, and acoustic filters.

New Soft Rock Pillar Strength Formula Derived Through Parametric FEA Using a Critical State Plasticity Model

NASA Astrophysics Data System (ADS)

Rastiello, Giuseppe; Federico, Francesco; Screpanti, Silvio

2015-09-01

Many abandoned room and pillar mines have been excavated not far from the surface of large areas of important European cities. In Rome, these excavations took place at shallow depths (3-15 m below the ground surface) in weak pyroclastic soft rocks. Many of these cavities have collapsed; others appear to be in a stable condition, although an appreciable percentage of their structural components (pillars, roofs, etc.) have shown increasing signs of distress from both the morphological and mechanical points of view. In this study, the stress-strain behaviour of soft rock pillars sustaining systems of cavities under vertical loads was numerically simulated, starting from the in situ initial conditions due to excavation of the cavities. The mechanical behaviour of the constituent material of the pillar was modelled according to the Modified Cam-Clay constitutive law (elasto-plastic with strain hardening). The influence of the pillar geometry (cross-section area, shape, and height) and mechanical parameters of the soft rock on the ultimate compressive strength of the pillar as a whole was parametrically investigated first. Based on the numerical results, an original relationship for pillar strength assessment was developed. Finally, the estimated pillar strengths according to the proposed formula and well-known formulations in the literature were compared.

Beyond DSM-5 and IQ Scores: Integrating the Four Pillars to Forensic Evaluations.

PubMed

Delgado, Sergio V; Barzman, Drew H

2017-03-01

The current adult and child forensic psychiatrist is well trained, familiar, and comfortable with the use of the semi-structured Diagnostic and Statistical Manual of Mental Disorders, 5th Edition, APA 2013 (DSM-5) [In APA, 2003] interview style. The author's assertion is not that this method is invalid or unreliable; rather, that it can be complemented by integrating elements of the defendant's four pillar assessment. Assessing the four pillars expands on the information provided by a semi-structured DSM-5-style interview in psychiatry. The four pillars are the foundation of a person's personality; temperament, cognition (learning abilities or weaknesses), cognitive flexibility (theory of mind) and internal working models of attachment, within the backdrop of the family and of the social and cultural environment in which they have lived. The importance of the study of four pillars is based on the understanding that human behavior and psychopathology as a complex and multifaceted process that includes the level of social-emotional maturity and cognitive abilities (In Delgado et al. Contemporary Psychodynamic Psychotherapy for Children and Adolescents: Integrating Intersubjectivity and Neuroscience. Springer, Berlin, 2015). The four pillars are not new concepts, rather they had been studied by separate non-clinical disciplines, and had not been integrated to the clinical practice. As far as we know, it wasn't until Delgado et al. (Contemporary Psychodynamic Psychotherapy for Children and Adolescents: Integrating Intersubjectivity and Neuroscience. Springer, Berlin, 2015) incorporated the four pillars in a user-friendly manner to clinical practice.

Zinc-coordinated MOFs complexes regulated by hydrogen bonds: Synthesis, structure and luminescence study toward broadband white-light emission

NASA Astrophysics Data System (ADS)

Duan, Hui; Dan, Wenyan; Fang, Xiangdong

2018-04-01

Two new compounds, namely {[Zn(apc)2]·H2O}n (1) and [Zn(apc)2(H2O)2] (2), have been designed and synthesized with a multi-functional ligand 2-aminopyrimidine-5-carboxylic acid (Hapc). Both compounds were characterized by single crystal X-ray diffraction analysis (SC-XRD), elemental analysis (EA), infrared spectroscopy (IR), and thermogravimetric analysis (TG). In solid-state structures, 1 features a two-fold interpenetrating pillared-layer 3D framework with point symbol {83}2{86}, referring to tfa topology; while 2 exhibits a 3D framework based on super unit of Zn(apc)2(H2O)2 interconnected via hydrogen bonds. Furthermore, the luminescent properties of 1 and 2 were discussed.

Laser jetting of femto-liter metal droplets for high resolution 3D printed structures

NASA Astrophysics Data System (ADS)

Zenou, M.; Sa'Ar, A.; Kotler, Z.

2015-11-01

Laser induced forward transfer (LIFT) is employed in a special, high accuracy jetting regime, by adequately matching the sub-nanosecond pulse duration to the metal donor layer thickness. Under such conditions, an effective solid nozzle is formed, providing stability and directionality to the femto-liter droplets which are printed from a large gap in excess of 400 μm. We illustrate the wide applicability of this method by printing several 3D metal objects. First, very high aspect ratio (A/R > 20), micron scale, copper pillars in various configuration, upright and arbitrarily bent, then a micron scale 3D object composed of gold and copper. Such a digital printing method could serve the generation of complex, multi-material, micron-scale, 3D materials and novel structures.

Single-step direct fabrication of pillar-on-pore hybrid nanostructures in anodizing aluminum for superior superhydrophobic efficiency.

PubMed

Jeong, Chanyoung; Choi, Chang-Hwan

2012-02-01

Conventional electrochemical anodizing processes of metals such as aluminum typically produce planar and homogeneous nanopore structures. If hydrophobically treated, such 2D planar and interconnected pore structures typically result in lower contact angle and larger contact angle hysteresis than 3D disconnected pillar structures and, hence, exhibit inferior superhydrophobic efficiency. In this study, we demonstrate for the first time that the anodizing parameters can be engineered to design novel pillar-on-pore (POP) hybrid nanostructures directly in a simple one-step fabrication process so that superior surface superhydrophobicity can also be realized effectively from the electrochemical anodization process. On the basis of the characteristic of forming a self-ordered porous morphology in a hexagonal array, the modulation of anodizing voltage and duration enabled the formulation of the hybrid-type nanostructures having controlled pillar morphology on top of a porous layer in both mild and hard anodization modes. The hybrid nanostructures of the anodized metal oxide layer initially enhanced the surface hydrophilicity significantly (i.e., superhydrophilic). However, after a hydrophobic monolayer coating, such hybrid nanostructures then showed superior superhydrophobic nonwetting properties not attainable by the plain nanoporous surfaces produced by conventional anodization conditions. The well-regulated anodization process suggests that electrochemical anodizing can expand its usefulness and efficacy to render various metallic substrates with great superhydrophilicity or -hydrophobicity by directly realizing pillar-like structures on top of a self-ordered nanoporous array through a simple one-step fabrication procedure.

Silicon based near infrared photodetector using self-assembled organic crystalline nano-pillars

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

Ajiki, Yoshiharu, E-mail: yoshiharu-ajiki@ot.olympus.co.jp, E-mail: isao@i.u-tokyo.ac.jp; Kan, Tetsuo; Yahiro, Masayuki

We propose a silicon (Si) based near-infrared photodetector using self-assembled organic crystalline nano-pillars, which were formed on an n-type Si substrate and were covered with an Au thin-film. These structures act as antennas for near-infrared light, resulting in an enhancement of the light absorption on the Au film. Because the Schottky junction is formed between the Au/n-type Si, the electron excited by the absorbed light can be detected as photocurrent. The optical measurement revealed that the nano-pillar structures enhanced the responsivity for the near-infrared light by 89 (14.5 mA/W) and 16 (0.433 mA/W) times compared with those of the photodetector without nano-pillarsmore » at the wavelengths of 1.2 and 1.3 μm, respectively. Moreover, no polarization dependency of the responsivity was observed, and the acceptable incident angle ranged from 0° to 30°. These broad responses were likely to be due to the organic nano-pillar structures' having variation in their orientation, which is advantageous for near-infrared detector uses.« less

Post-mortem characterization of fs laser-generated micro-pillars in Li(Ni1/3Mn1/3Co1/3)O2 electrodes by laser-induced breakdown spectroscopy

NASA Astrophysics Data System (ADS)

Smyrek, P.; Zheng, Y.; Seifert, H. J.; Pfleging, W.

2016-03-01

NMC thick films were prepared by tape-casting and subsequent ultrafast laser-structuring. The lithium distribution in electrochemically cycled and unstructured or fs laser-structured NMC cathodes was investigated by using Laser-Induced Breakdown Spectroscopy (LIBS). The main goal is to develop an optimized three dimensional cell architecture with improved electrochemical properties based on studies of the homogeneity of the local State-of-Charge. LIBS experiments were carried out using a LIBS workstation equipped with a mode-locked diode pumped solid state Nd:YAG laser operating at a wavelength of 1063 nm. The element distribution was investigated using two different techniques: element mapping and element depth-profiling of the unstructured / fs laser-structured electrode surface. Results achieved from post-mortem studies using LIBS will be presented.

Two Zinc(II) metal-organic frameworks with mixed ligands of 5-amino-tetrazolate and l,2,4,5-benzenetetracarboxylate: Synthesis, structural diversity and photoluminescent properties

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

Wang, Xiao-Bing; Lu, Wen-Guan, E-mail: lwg@sgu.edu.cn; Zhong, Di-Chang

The reactions of Zn(NO{sub 3}){sub 2}·6H{sub 2}O with mixed ligands of 5-amino-tetrazole (Hatz) and l,2,4,5-benzenetetracarboxylic acid (H{sub 4}btec) under hydro(solvo)thermal conditions, gave two three-dimensional (3D) porous metal-organic frameworks (MOFs) of ([Zn{sub 3}(atz){sub 2}(btec)(DMF){sub 2}]·DMF·2H{sub 2}O){sub n} (1) and [Zn{sub 2}(Hprz)(atz)(btec)(H{sub 2}O)]{sub n} (2) in the absence and presence of piperazine (prz), respectively. 1 and 2 were characterized by infrared spectra (IR), elemental analyses (EA) and single-crystal/powder X-ray diffraction. In 1, the adjacent 1D [Zn{sub 3}(btec)]{sub n}{sup 2n+} chains are linked together by atz{sup −} ligands to form a 3D porous MOF with 1D tetragonal channels filled with coordinated and guestmore » DMF, and lattice water molecules. In 2, the adjacent 2D [Zn{sub 2}(btec)]{sub n} wavelike sheets are pillared through atz{sup −} ligands to generate a 3D layered-pillared porous MOF with 1D open channels, which are occupied by coordinated Hprz{sup +} cations and coordinated water molecules. Additionally, thermal stabilities and photoluminescent properties of both compounds in the solid-state at room temperature have been investigated and discussed in detail. - Graphical abstract: Two new MOFs constructed from Zn(II) salts with mixed ligands of 5-amino-tetrazole and l,2,4,5-benzenetetracarboxylic acid were synthesized under different reaction conditions. Structural diversities indicate that the reaction solvent system or the presence of organic base play crucial roles in modulating structures of these compounds. And more, their thermal stability and luminescence are also discussed. - Highlights: • Two new Zn(II) MOFs based on mixed ligands were synthesized. • The two Zn(II) MOFs exhibit different structural motifs. • The two Zn(II) MOFs are photoluminscent in the solid state at room temperature.« less

Photonic Waveguide Choke Joint with Absorptive Loading

NASA Technical Reports Server (NTRS)

Wollack, Edward J. (Inventor); U-Yen, Kongpop (Inventor); Chuss, David T. (Inventor)

2016-01-01

A photonic waveguide choke includes a first waveguide flange member having periodic metal tiling pillars, a dissipative dielectric material positioned within an area between the periodic metal tiling pillars and a second waveguide flange member disposed to be coupled with the first waveguide flange member and in spaced-apart relationship separated by a gap. The first waveguide flange member has a substantially smooth surface, and the second waveguide flange member has an array of two-dimensional pillar structures formed therein.

High-aspect-ratio, silicon oxide-enclosed pillar structures in microfluidic liquid chromatography.

PubMed

Taylor, Lisa C; Lavrik, Nickolay V; Sepaniak, Michael J

2010-11-15

The present paper discusses the ability to separate chemical species using high-aspect-ratio, silicon oxide-enclosed pillar arrays. These miniaturized chromatographic systems require smaller sample volumes, experience less flow resistance, and generate superior separation efficiency over traditional packed bed liquid chromatographic columns, improvements controlled by the increased order and decreased pore size of the systems. In our distinctive fabrication sequence, plasma-enhanced chemical vapor deposition (PECVD) of silicon oxide is used to alter the surface and structural properties of the pillars for facile surface modification while improving the pillar mechanical stability and increasing surface area. The separation behavior of model compounds within our pillar systems indicated an unexpected hydrophobic-like separation mechanism. The effects of organic modifier, ionic concentration, and pressure-driven flow rate were studied. A decrease in the organic content of the mobile phase increased peak resolution while detrimentally effecting peak shape. A resolution of 4.7 (RSD = 3.7%) was obtained for nearly perfect Gaussian shaped peaks, exhibiting plate heights as low as 1.1 and 1.8 μm for fluorescein and sulforhodamine B, respectively. Contact angle measurements and DART mass spectrometry analysis indicate that our employed elastomeric soft bonding technique modifies pillar properties, creating a fortuitous stationary phase. This discovery provides evidence supporting the ability to easily functionalize PECVD oxide surfaces by gas-phase reactions.

Detailed Numerical Simulations on the Formation of Pillars Around H II Regions

NASA Astrophysics Data System (ADS)

Gritschneder, Matthias; Burkert, Andreas; Naab, Thorsten; Walch, Stefanie

2010-11-01

We study the structural evolution of turbulent molecular clouds under the influence of ionizing radiation emitted from a nearby massive star by performing a high-resolution parameter study with the iVINE code. The temperature is taken to be 10 K or 100 K, the mean number density is either 100 cm-3 or 300 cm-3. Furthermore, the turbulence is varied between Mach 1.5 and Mach 12.5, the main driving scale of the turbulence is varied between 1 pc and 8 pc. We vary the ionizing flux by an order of magnitude, corresponding to allowing between 0.5% and 5% of the mass in the domain to be ionized immediately. In our simulations, the ionizing radiation enhances the initial turbulent density distribution and thus leads to the formation of pillar-like structures observed adjacent to H II regions in a natural way. Gravitational collapse occurs regularly at the tips of the structures. We find a clear correlation between the initial state of the turbulent cold cloud and the final morphology and physical properties of the structures formed. The most favorable regime for the formation of pillars is Mach 4-10. Structures and therefore stars only form if the initial density contrast between the high-density unionized gas and the gas that is going to be ionized is lower than the temperature contrast between the hot and the cold gas. The density of the resulting pillars is determined by a pressure equilibrium between the hot and the cold gas. A thorough analysis of the simulations shows that the complex kinematical and geometrical structure of the formed elongated filaments reflects that of observed pillars to an impressive level of detail. In addition, we find that the observed line-of-sight velocities allow for a distinct determination of different formation mechanisms. Comparing the current simulations to previous results and recent observations, we conclude that, e.g., the pillars of creation in M16 formed by the mechanism proposed here and not by the radiation driven implosion of pre-existing clumps.

DETAILED NUMERICAL SIMULATIONS ON THE FORMATION OF PILLARS AROUND H II REGIONS

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

Gritschneder, Matthias; Burkert, Andreas; Naab, Thorsten

2010-11-10

We study the structural evolution of turbulent molecular clouds under the influence of ionizing radiation emitted from a nearby massive star by performing a high-resolution parameter study with the iVINE code. The temperature is taken to be 10 K or 100 K, the mean number density is either 100 cm{sup -3} or 300 cm{sup -3}. Furthermore, the turbulence is varied between Mach 1.5 and Mach 12.5, the main driving scale of the turbulence is varied between 1 pc and 8 pc. We vary the ionizing flux by an order of magnitude, corresponding to allowing between 0.5% and 5% of themore » mass in the domain to be ionized immediately. In our simulations, the ionizing radiation enhances the initial turbulent density distribution and thus leads to the formation of pillar-like structures observed adjacent to H II regions in a natural way. Gravitational collapse occurs regularly at the tips of the structures. We find a clear correlation between the initial state of the turbulent cold cloud and the final morphology and physical properties of the structures formed. The most favorable regime for the formation of pillars is Mach 4-10. Structures and therefore stars only form if the initial density contrast between the high-density unionized gas and the gas that is going to be ionized is lower than the temperature contrast between the hot and the cold gas. The density of the resulting pillars is determined by a pressure equilibrium between the hot and the cold gas. A thorough analysis of the simulations shows that the complex kinematical and geometrical structure of the formed elongated filaments reflects that of observed pillars to an impressive level of detail. In addition, we find that the observed line-of-sight velocities allow for a distinct determination of different formation mechanisms. Comparing the current simulations to previous results and recent observations, we conclude that, e.g., the pillars of creation in M16 formed by the mechanism proposed here and not by the radiation driven implosion of pre-existing clumps.« less

Pillared Structure Design of MXene with Ultralarge Interlayer Spacing for High-Performance Lithium-Ion Capacitors.

PubMed

Luo, Jianmin; Zhang, Wenkui; Yuan, Huadong; Jin, Chengbin; Zhang, Liyuan; Huang, Hui; Liang, Chu; Xia, Yang; Zhang, Jun; Gan, Yongping; Tao, Xinyong

2017-03-28

Two-dimensional transition-metal carbide materials (termed MXene) have attracted huge attention in the field of electrochemical energy storage due to their excellent electrical conductivity, high volumetric capacity, etc. Herein, with inspiration from the interesting structure of pillared interlayered clays, we attempt to fabricate pillared Ti 3 C 2 MXene (CTAB-Sn(IV)@Ti 3 C 2 ) via a facile liquid-phase cetyltrimethylammonium bromide (CTAB) prepillaring and Sn 4+ pillaring method. The interlayer spacing of Ti 3 C 2 MXene can be controlled according to the size of the intercalated prepillaring agent (cationic surfactant) and can reach 2.708 nm with 177% increase compared with the original spacing of 0.977 nm, which is currently the maximum value according to our knowledge. Because of the pillar effect, the assembled LIC exhibits a superior energy density of 239.50 Wh kg -1 based on the weight of CTAB-Sn(IV)@Ti 3 C 2 even under higher power density of 10.8 kW kg -1 . When CTAB-Sn(IV)@Ti 3 C 2 anode couples with commercial AC cathode, LIC reveals higher energy density and power density compared with conventional MXene materials.

Pillars and globules at the edges of H ii regions. Confronting Herschel observations and numerical simulations

NASA Astrophysics Data System (ADS)

Tremblin, P.; Minier, V.; Schneider, N.; Audit, E.; Hill, T.; Didelon, P.; Peretto, N.; Arzoumanian, D.; Motte, F.; Zavagno, A.; Bontemps, S.; Anderson, L. D.; André, Ph.; Bernard, J. P.; Csengeri, T.; Di Francesco, J.; Elia, D.; Hennemann, M.; Könyves, V.; Marston, A. P.; Nguyen Luong, Q.; Rivera-Ingraham, A.; Roussel, H.; Sousbie, T.; Spinoglio, L.; White, G. J.; Williams, J.

2013-12-01

Context. Herschel far-infrared imaging observations have revealed the density structure of the interface between H ii regions and molecular clouds in great detail. In particular, pillars and globules are present in many high-mass star-forming regions, such as the Eagle nebula (M 16) and the Rosette molecular cloud, and understanding their origin will help characterize triggered star formation. Aims: The formation mechanisms of these structures are still being debated. The initial morphology of the molecular cloud and its turbulent state are key parameters since they generate deformations and curvatures of the shell during the expansion of the H ii region. Recent numerical simulations have shown how pillars can arise from the collapse of the shell in on itself and how globules can be formed from the interplay of the turbulent molecular cloud and the ionization from massive stars. The goal here is to test this scenario through recent observations of two massive star-forming regions, M 16 and the Rosette molecular cloud. Methods: First, the column density structure of the interface between molecular clouds and associated H ii regions was characterized using column density maps obtained from far-infrared imaging of the Herschel HOBYS key programme. Then, the DisPerSe algorithm was used on these maps to detect the compressed layers around the ionized gas and pillars in different evolutionary states. Column density profiles were constructed. Finally, their velocity structure was investigated using CO data, and all observational signatures were tested against some distinct diagnostics established from simulations. Results: The column density profiles have revealed the importance of compression at the edge of the ionized gas. The velocity properties of the structures, i.e. pillars and globules, are very close to what we predict from the numerical simulations. We have identified a good candidate of a nascent pillar in the Rosette molecular cloud that presents the velocity pattern of the shell collapsing on itself, induced by a high local curvature. Globules have a bulk velocity dispersion that indicates the importance of the initial turbulence in their formation, as proposed from numerical simulations. Altogether, this study re-enforces the picture of pillar formation by shell collapse and globule formation by the ionization of highly turbulent clouds. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Bioinspired Surface for Surgical Graspers Based on the Strong Wet Friction of Tree Frog Toe Pads.

PubMed

Chen, Huawei; Zhang, Liwen; Zhang, Deyuan; Zhang, Pengfei; Han, Zhiwu

2015-07-01

Soft tissue damage is often at risk during the use of a surgical grasper, because of the strong holding force required to prevent slipping of the soft tissue in wet surgical environments. Improvement of wet friction properties at the interface between the surgical grasper and soft tissue can greatly reduce the holding force required and, thus, the soft tissue damage. To design and fabricate a biomimetic microscale surface with strong wet friction, the wet attachment mechanism of tree frog toe pads was investigated by observing their epithelial cell structure and the directionally dependent friction on their toe pads. Using these observations as inspiration, novel surface micropatterns were proposed for the surface of surgical graspers. The wet friction of biomimetic surfaces with various types of polygon pillar patterns involving quadrangular pillars, triangular pillars, rhomboid pillars, and varied hexagonal pillars were tested. The hexagonal pillar pattern exhibited improved wet frictional performance over the modern surgical grasper jaw pattern, which has conventional macroscale teeth. Moreover, the deformation of soft tissue in the bioinspired surgical grasper with a hexagonal pillar pattern is decreased, compared with the conventional surgical grasper.

Two-Dimensional Wetting Transition Modeling with the Potts Model

NASA Astrophysics Data System (ADS)

Lopes, Daisiane M.; Mombach, José C. M.

2017-12-01

A droplet of a liquid deposited on a surface structured in pillars may have two states of wetting: (1) Cassie-Baxter (CB), the liquid remains on top of the pillars, also known as heterogeneous wetting, or (2) Wenzel, the liquid fills completely the cavities of the surface, also known as homogeneous wetting. Studies show that between these two states, there is an energy barrier that, when overcome, results in the transition of states. The transition can be achieved by changes in geometry parameters of the surface, by vibrations of the surface or by evaporation of the liquid. In this paper, we present a comparison of two-dimensional simulations of the Cassie-Wenzel transition on pillar-structured surfaces using the cellular Potts model (CPM) with studies performed by Shahraz et al. In our work, we determine a transition diagram by varying the surface parameters such as the interpillar distance ( G) and the pillar height ( H). Our results were compared to those obtained by Shahraz et al. obtaining good agreement.

Stress Changes and Deformation Monitoring of Longwall Coal Pillars Located in Weak Ground

NASA Astrophysics Data System (ADS)

Yu, Bin; Zhang, Zhenyu; Kuang, Tiejun; Liu, Jinrong

2016-08-01

Coal pillar stability is strongly influenced by the site-specific geological and geotechnical conditions. Many geological structures such as faults, joints, or rock intrusions can be detrimental to mining operations. In order to evaluate the performance of coal pillars under weak roof degraded by igneous rock intrusion, stress and deformation monitoring was conducted in the affected tailgate areas of Nos. 8208 and 8210 longwalls in Tashan coal mine, Shanxi Province, China. The measurements in the 8208 longwall tailgate showed that the mining-induced stresses in 38-m-wide coal chain pillars under the overburden depth of 300-500 m started to increase at about 100 m ahead of the 8208 longwall working face and reached its peak level at approximately 50 m ahead of the longwall face. The peak stress of 9.16 MPa occurred at the depth of 8-9 m into the pillar from the tailgate side wall. In comparison, disturbance of the headgate block pillar area was negligible, indicating the difference of abutment pressure distribution between the tailgate and headgate sites where the adjacent unmined longwall block carried most of the overburden load. However, when the longwall face passed the headgate monitoring site by 360-379 m, the pillar stress increased to a peak value of 21.4 MPa at the pillar depth of 13 m from the gob side mainly due to stress redistribution in the chain pillar. In contrast to the headgate, at the tailgate side, the adjacent goaf was the dominant triggering factor for high stress concentrations in the chain pillar. Convergence measurements in the tailgate during longwall mining further indicated the evolution characteristics of coal pillar deformation, clearly showing that the gateroad deformation is mainly induced by the longwall extraction it serves. When predicting the future pillar loads from the monitored data, two stress peaks appeared across the 38-m-wide tailgate coal pillar, which are separated by the lower stress area within the pillar center. This 10-m-wide elastic pillar core area indicates that the coal pillar may be narrowed to 30 m to improve coal recovery. The measurements further indicate that, if the headgate of the next panel can be developed after the adjacent gob becomes stable, the coal pillar width may be further reduced to 20 m. This study is applicable for the chain pillar design, the gateroad secondary support design ahead of the longwall mining face, and the gateroad preparation of the next longwall panel under similar geological and geotechnical conditions.

Method for Texturing Surfaces of Optical Fiber Sensors Used for Blood Glucose Monitoring

NASA Technical Reports Server (NTRS)

Banks, Bruce A. (Inventor)

2007-01-01

Disclosed is a method and the resulting product thereof comprising a solid light-conducting fiber with a point of attachment and having a textured surface site consisting a textured distal end prepared by being placed in a vacuum and then subjected to directed hyperthermal beams comprising oxygen ions or atoms. The textured distal end comprises cones or pillars that are spaced upon from each other by less than 1 micron and are extremely suitable to prevent cellular components of blood from entering the valleys between the cones or pillars so as to effectively separate the cellular components in the blood from interfering with optical sensing of the glucose concentration for diabetic patients.

Energetic Atomic and Ionic Oxygen Textured Optical Surfaces for Blood Glucose Monitoring

NASA Technical Reports Server (NTRS)

Banks, Bruce A. (Inventor)

2007-01-01

Disclosed is a method and the resulting product thereof comprising a solid light-conducting fiber with a point of attachment and having a textured surface site consisting of a textured distal end prepared by being placed in a vacuum and then subjected to directed hyperthermal beams comprising oxygen ions or atoms. The textured distal end comprises cones or pillars that are spaced upon from each other by less than 1 micron and are extremely suitable to prevent cellular components of blood from entering the valleys between the cones or pillars so as to effectively separate the cellular components in the blood from interfering with optical sensing of the glucose concentration for diabetic patients.

Energetic atomic and ionic oxygen textured optical surfaces for blood glucose monitoring

NASA Technical Reports Server (NTRS)

Banks, Bruce A. (Inventor)

2007-01-01

Disclosed is a method and the resulting product thereof comprising a solid light-conducting fiber with a point of attachment and having a textured surface site consisting a textured distal end prepared by being placed in a vacuum and then subjected to directed hyperthermal beams comprising oxygen ions or atoms. The textured distal end comprises cones or pillars that are spaced upon from each other by less than 1 micron and are extremely suitable to prevent cellular components of blood from entering the valleys between the cones or pillars so as to effectively separate the cellular components in the blood from interfering with optical sensing of the glucose concentration for diabetic patients.

Copper pillar and memory characteristics using Al2O3 switching material for 3D architecture.

PubMed

Maikap, Siddheswar; Panja, Rajeswar; Jana, Debanjan

2014-01-01

A novel idea by using copper (Cu) pillar is proposed in this study, which can replace the through-silicon-vias (TSV) technique in future three-dimensional (3D) architecture. The Cu pillar formation under external bias in an Al/Cu/Al2O3/TiN structure is simple and low cost. The Cu pillar is formed in the Al2O3 film under a small operation voltage of <5 V and a high-current-carrying conductor of >70 mA is obtained. More than 100 devices have shown tight distribution of the Cu pillars in Al2O3 film for high current compliance (CC) of 70 mA. Robust read pulse endurances of >10(6) cycles are observed with read voltages of -1, 1, and 4 V. However, read endurance is failed with read voltages of -1.5, -2, and -4 V. By decreasing negative read voltage, the read endurance is getting worst, which is owing to ruptured Cu pillar. Surface roughness and TiO x N y on TiN bottom electrode are observed by atomic force microscope and transmission electron microscope, respectively. The Al/Cu/Al2O3/TiN memory device shows good bipolar resistive switching behavior at a CC of 500 μA under small operating voltage of ±1 V and good data retention characteristics of >10(3) s with acceptable resistance ratio of >10 is also obtained. This suggests that high-current operation will help to form Cu pillar and lower-current operation will have bipolar resistive switching memory. Therefore, this new Cu/Al2O3/TiN structure will be benefited for 3D architecture in the future.

Effect of fibril shape on adhesive properties

NASA Astrophysics Data System (ADS)

Soto, Daniel; Hill, Ginel; Parness, Aaron; Esparza, Noé; Cutkosky, Mark; Kenny, Tom

2010-08-01

Research into the gecko's adhesive system revealed a unique architecture for adhesives using tiny hairs. By using a stiff material (β-keratin) to create a highly structured adhesive, the gecko's system demonstrates properties not seen in traditional pressure-sensitive adhesives which use a soft, unstructured planar layer. In contrast to pressure sensitive adhesives, the gecko adhesive displays frictional adhesion, in which increased shear force allows it to withstand higher normal loads. Synthetic fibrillar adhesives have been fabricated but not all demonstrate this frictional adhesion property. Here we report the dual-axis force testing of single silicone rubber pillars from synthetic adhesive arrays. We find that the shape of the adhesive pillar dictates whether frictional adhesion or pressure-sensitive behavior is observed. This work suggests that both types of behavior can be achieved with structures much larger than gecko terminal structures. It also indicates that subtle differences in the shape of these pillars can significantly influence their properties.

Connecting the dots: a correlation between ionizing radiation and cloud mass-loss rate traced by optical integral field spectroscopy

NASA Astrophysics Data System (ADS)

McLeod, A. F.; Gritschneder, M.; Dale, J. E.; Ginsburg, A.; Klaassen, P. D.; Mottram, J. C.; Preibisch, T.; Ramsay, S.; Reiter, M.; Testi, L.

2016-11-01

We present an analysis of the effect of feedback from O- and B-type stars with data from the integral field spectrograph Multi Unit Spectroscopic Explorer (MUSE) mounted on the Very Large Telescope of pillar-like structures in the Carina Nebular Complex, one of the most massive star-forming regions in the Galaxy. For the observed pillars, we compute gas electron densities and temperatures maps, produce integrated line and velocity maps of the ionized gas, study the ionization fronts at the pillar tips, analyse the properties of the single regions, and detect two ionized jets originating from two distinct pillar tips. For each pillar tip, we determine the incident ionizing photon flux Q0, pil originating from the nearby massive O- and B-type stars and compute the mass-loss rate dot{M} of the pillar tips due to photoevaporation caused by the incident ionizing radiation. We combine the results of the Carina data set with archival MUSE data of a pillar in NGC 3603 and with previously published MUSE data of the Pillars of Creation in M16, and with a total of 10 analysed pillars, find tight correlations between the ionizing photon flux and the electron density, the electron density and the distance from the ionizing sources, and the ionizing photon flux and the mass-loss rate. The combined MUSE data sets of pillars in regions with different physical conditions and stellar content therefore yield an empirical quantification of the feedback effects of ionizing radiation. In agreement with models, we find that dot{M}∝ Q_0,pil^{1/2}.

Effects of Matrix Alignment and Mechanical Constraints on Cellular Behavior in 3D Engineered Microtissues

NASA Astrophysics Data System (ADS)

Bose, Prasenjit; Eyckmans, Jeroen; Chen, Christopher; Reich, Daniel

The adhesion of cells to the extracellular matrix (ECM) plays a crucial role in a variety of cellular functions. The main building blocks of the ECM are 3D networks of fibrous proteins whose structure and alignments varies with tissue type. However, the impact of ECM alignment on cellular behaviors such as cell adhesion, spreading, extension and mechanics remains poorly understood. We present results on the development of a microtissue-based system that enables control of the structure, orientation, and degree of fibrillar alignment in 3D fibroblast-populated collagen gels. The tissues self-assemble from cell-laden collagen gels placed in micro-fabricated wells containing sets of elastic pillars. The contractile action of the cells leads to controlled alignment of the fibrous collagen, depending on the number and location of the pillars in each well. The pillars are elastic, and are utilized to measure the contractile forces of the microtissues, and by incorporating magnetic material in selected pillars, time-varying forces can be applied to the tissues for dynamic stimulation and measurement of mechanical properties. Results on the effects of varying pillar shape, spacing, location, and stiffness on microtissue organization and contractility will be presented. This work is supported by NSF CMMI-1463011.

Device properties of nanopore PN junction Si for photovoltaic application

NASA Astrophysics Data System (ADS)

Jin, Hyunjong; Chang, Te Wei; Liu, Logan Gang

2011-09-01

Improvement of energy conversion efficiency of solar cells has led to innovative approaches, in particular the introduction of nanopillar photovoltaics [1]. Previous work on nanopillar Si photovoltaic has shown broadband reduction in optical reflection and enhancement of absorption [2]. Radial or axial PN junctions [3, 4] have been of high interest for improved photovoltaic devices. However, with the PN junction incorporated as part of the pillar, the discreteness of individual pillar requires additional conductive layer that would electrically short the top of each pillar for efficient carrier extraction. The fragile structure of the surface pillars would also require a protection layer for possible mechanical scratch to prevent pillars from breaking. Any additional layer that is applied, either for electrical contact or for mechanical properties may introduce additional recombination sites and also reduce the actual light absorption by the photovoltaic material. In this paper, nanopore Si photovoltaics that not only provides the advantages but also addresses the challenges of nanopillers is demonstrated. PN junction substrate of 250 nm thick N-type polycrystalline Si on P-type Si wafer is prepared. The nanopore structure is formed by using anodized aluminum oxide (AAO) as an etching mask against deep reactive ionic etching (DRIE). The device consists of semi-ordered pores of ~70 nm diameter.

Single-Crystalline InGaAs/InP Dense Micro-Pillar Forest on Poly-Silicon Substrates for Low-Cost High-Efficiency Solar Cells

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

Chang-Hasnain, Constance

2015-05-04

The ultimate goal of this project is to develop a photovoltaic system high conversion efficiency (>20%) using high quality III-V compound-based three-dimensional micro-structures on silicon and poly-silicon. Such a PV-system could be of very low cost due to minimum usages of III-V materials. This project will address the barriers that currently hamper the performance of solar cells based on three-dimensional micro-structures. To accomplish this goal the project is divided into 4 tasks, each dealing with a different aspect of the project: materials quality, micropillar growth control, light management, and pillar based solar cells. Materials Quality: the internal quantum efficiency (IQE)more » - by which is meant here the internal fluorescence yield - of the micro-pillars has to be increased. We aim at achieving an IQE of 45% by the end of the first year. By the end of the second year there will be a go-no-go milestone of 65% IQE. By the end of year 3 and 4 we aim to achieve 75% and 90% IQE, respectively. Micropillar growth control: dense forests of micropillars with high fill ratios need to be grown. Pillars within forests should show minimum variations in size. We aim at achieving fill ratios of 2%, 10%, >15%, >20% in years 1, 2, 3, and 4, respectively. Variations in dimension should be minimized by site-controlled growth of pillars. By the end of year 1 we will aim at achieving site-controlled growth with > 15% yield. By end of year 2 the variation of critical pillar dimensions should be less than 25%. Light management: high light absorption in the spectral range of the sun has been to be demonstrated for the micropillar forests. By the end of year 1 we will employ FDTD simulation techniques to demonstrate that pillar forests with fill ratios <20% can achieve 99% light absorption. By end of year 2 our original goal was to demonstrate >85% absorption. By end of year 3 > 90% absorption should be demonstrated. Pillar based solar cells: devices will be studied to explore ways to achieve high open-circuit voltages which will lead to high efficiency micropillar-based solar cells. We will start on single pillar devices and the findings in these studies should pave the way for devices based on forests/ arrays of pillars. By the end of the second year we aim to demonstrate a single pillar device with an open-circuit voltage of 0.7 V, as well as a pillar-forest based device with 8% conversion efficiency. By the end of year 3 these numbers should be improved to 0.9 V open-circuit voltage for single pillar devices and >15% efficiency for forest/array-based devices. We will aim to realize a device with 20% efficiency by the end of the project period.« less

3D homometallic carboxylate ferrimagnet constructed from a manganese(II) succinate carboxylate layer motif pillared by isonicotinate spacers.

PubMed

Zeng, Ming-Hua; Wu, Mei-Chun; Liang, Hong; Zhou, Yan-Ling; Chen, Xiao-Ming; Ng, Seik-Weng

2007-09-03

A manganese succinate having a layer structure in which the layers are pillared by the isonicotinate spacers in a 3D architecture exhibits long-range ferrimagnetic order below 5.0 K, with the ferrimagnetism arising, for topological reasons, from the nature of the carboxylate binding modes. The compound is the first structurally authenticated example of a 3D ferrimagnet, featuring a homometallic topological ferrimagnetic sheet among metal carboxylates.

49 CFR 571.213 - Standard No. 213; Child restraint systems.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., the floor pan, adjacent pillars (e.g., the B and C pillars), and the ceiling. If the built-in system... in S7. (c) Each child restraint system manufactured for use in aircraft shall meet the requirements... contactable surface of any structural element of the system. (b)(1) If adjustable to different positions...

49 CFR 571.213 - Standard No. 213; Child restraint systems.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., the floor pan, adjacent pillars (e.g., the B and C pillars), and the ceiling. If the built-in system... in S7. (c) Each child restraint system manufactured for use in aircraft shall meet the requirements... contactable surface of any structural element of the system. (b)(1) If adjustable to different positions...

Flipping the Switch: Fast Photoisomerization in a Confined Environment.

PubMed

Williams, Derek E; Martin, Corey R; Dolgopolova, Ekaterina A; Swifton, Anton; Godfrey, Danielle C; Ejegbavwo, Otega A; Pellechia, Perry J; Smith, Mark D; Shustova, Natalia B

2018-05-28

Stimuli-responsive materials are vital for addressing emerging demands in the advanced technology sector as well as current industrial challenges. Here, we report for the first time that coordinative integration of photoresponsive building blocks possessing photochromic spiropyran and diarylethene moieties within a rigid scaffold of metal-organic frameworks (MOFs) could control photophysics; in particular, cycloreversion kinetics with the level of control, which is not accessible in the solid state or solution. On the series of photoactive materials, we demonstrated for the first time that photoisomerization rates of photochromic compounds could be tuned within almost two orders of magnitude. Moreover, cycloreversion rates of photoresponsive derivatives could be modulated as a function of the framework structure. Furthermore, through MOF engineering we were able to achieve complete isomerization for coordinatively immobilized spiropyran derivatives, typically exhibiting limited photoswitching behavior in the solid state. For instance, spectroscopic analysis revealed that the novel monosubstituted spiropyran derivative grafted to the backbone of the MOF pillar exhibits a remarkable photoisomerization rate of 0.16 s-1, typical for cycloreversion in solution. We also applied the acquired fundamental principles towards mapping of changes in material properties, which could provide a pathway for monitoring material aging or structural deterioration.

Near-Infrared Polarimetry of the Eagle Nebula (M 16)

NASA Astrophysics Data System (ADS)

Sugitani, Koji; Watanabe, Makoto; Tamura, Motohide; Kandori, Ryo; Hough, James H.; Nishiyama, Shogo; Nakajima, Yasushi; Kusakabe, Nobuhiko; Hashimoto, Jun; Nagayama, Takahiro; Nagashima, Chie; Kato, Daisuke; Fukuda, Naoya

2007-06-01

We carried out deep and wide (˜ 8 × 8) JHKs imaging polarimetry in the southern region of the Eagle Nebula (M 16). The polarization intensity map reveals that two YSOs with near-IR reflection nebulae are located at the tips of two famous molecular pillars (Pillars 1 and 2) facing toward the exciting stars of M 16. The centrosymmetric polarization pattern are consistent with those around Class I objects having circumstellar envelopes, confirming that star formation is now taking place at the two tips of the pillars under the influence of UV radiation from the exciting stars. Polarization measurements of point sources show that magnetic fields are aligned along some of the pillars, but in a direction that is quite different to the global structure in M 16.

Toughening mechanisms in bioinspired multilayered materials.

PubMed

Askarinejad, Sina; Rahbar, Nima

2015-01-06

Outstanding mechanical properties of biological multilayered materials are strongly influenced by nanoscale features in their structure. In this study, mechanical behaviour and toughening mechanisms of abalone nacre-inspired multilayered materials are explored. In nacre's structure, the organic matrix, pillars and the roughness of the aragonite platelets play important roles in its overall mechanical performance. A micromechanical model for multilayered biological materials is proposed to simulate their mechanical deformation and toughening mechanisms. The fundamental hypothesis of the model is the inclusion of nanoscale pillars with near theoretical strength (σth ~ E/30). It is also assumed that pillars and asperities confine the organic matrix to the proximity of the platelets, and, hence, increase their stiffness, since it has been previously shown that the organic matrix behaves more stiffly in the proximity of mineral platelets. The modelling results are in excellent agreement with the available experimental data for abalone nacre. The results demonstrate that the aragonite platelets, pillars and organic matrix synergistically affect the stiffness of nacre, and the pillars significantly contribute to the mechanical performance of nacre. It is also shown that the roughness induced interactions between the organic matrix and aragonite platelet, represented in the model by asperity elements, play a key role in strength and toughness of abalone nacre. The highly nonlinear behaviour of the proposed multilayered material is the result of distributed deformation in the nacre-like structure due to the existence of nano-asperities and nanopillars with near theoretical strength. Finally, tensile toughness is studied as a function of the components in the microstructure of nacre.

Toughening mechanisms in bioinspired multilayered materials

PubMed Central

Askarinejad, Sina; Rahbar, Nima

2015-01-01

Outstanding mechanical properties of biological multilayered materials are strongly influenced by nanoscale features in their structure. In this study, mechanical behaviour and toughening mechanisms of abalone nacre-inspired multilayered materials are explored. In nacre's structure, the organic matrix, pillars and the roughness of the aragonite platelets play important roles in its overall mechanical performance. A micromechanical model for multilayered biological materials is proposed to simulate their mechanical deformation and toughening mechanisms. The fundamental hypothesis of the model is the inclusion of nanoscale pillars with near theoretical strength (σth ~ E/30). It is also assumed that pillars and asperities confine the organic matrix to the proximity of the platelets, and, hence, increase their stiffness, since it has been previously shown that the organic matrix behaves more stiffly in the proximity of mineral platelets. The modelling results are in excellent agreement with the available experimental data for abalone nacre. The results demonstrate that the aragonite platelets, pillars and organic matrix synergistically affect the stiffness of nacre, and the pillars significantly contribute to the mechanical performance of nacre. It is also shown that the roughness induced interactions between the organic matrix and aragonite platelet, represented in the model by asperity elements, play a key role in strength and toughness of abalone nacre. The highly nonlinear behaviour of the proposed multilayered material is the result of distributed deformation in the nacre-like structure due to the existence of nano-asperities and nanopillars with near theoretical strength. Finally, tensile toughness is studied as a function of the components in the microstructure of nacre. PMID:25551150

In situ synthesis, characterization, and catalytic performance of tungstophosphoric acid encapsulated into the framework of mesoporous silica pillared clay.

PubMed

Li, Baoshan; Liu, Zhenxing; Han, Chunying; Ma, Wei; Zhao, Songjie

2012-07-01

Mesoporous silica pillared clay (SPC) incorporated with tungstophosphoric acid (HPW) has been synthesized via in situ introducing P and W source in the acidic suspension of the clay interlayer template during the formation of the silica pillared clay. The samples were characterized by XRD, XRF, FT-IR, TG-DTA, N(2) adsorption-desorption, and SEM techniques. The results showed that the HPW formed by in situ method has been effectively introduced into the framework of mesoporous silica pillared clay and its Keggin structure remained perfectly after formation of the materials. In addition, samples with similar HPW loadings were also prepared by impregnation method using SPC as the support. HPW in the incorporated samples was better dispersed into the silica pillared clay than in the impregnated samples. The results of catalytic tests indicated that the encapsulated materials demonstrated better catalytic performance than the impregnated samples in oxidative desulfurization (ODS) of dibenzothiophene (DBT). Copyright © 2012 Elsevier Inc. All rights reserved.

Wettability behavior of water droplet on organic-polluted fused quartz surfaces of pillar-type nanostructures applying molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Chen, Jiaxuan; Chen, Wenyang; Xie, Yajing; Wang, Zhiguo; Qin, Jianbo

2017-02-01

Molecular dynamics (MD) is applied to research the wettability behaviors of different scale of water clusters absorbed on organic-polluted fused quartz (FQ) surface and different surface structures. The wettability of water clusters is studied under the effect of organic pollutant. With the combined influence of pillar height and interval, the stair-step Wenzel-Cassie transition critical line is obtained by analyzing stable state of water clusters on different surface structures. The results also show that when interval of pillars and the height of pillars keep constant respectively, the changing rules are exactly the opposite and these are termed as the "waterfall" rules. The substrate models of water clusters at Cassie-Baxter state which are at the vicinity of critical line are chosen to analyze the relationship of HI (refers to the pillar height/interval) ratio and scale of water cluster. The study has found that there is a critical changing threshold in the wettability changing process. When the HI ratio keeps constant, the wettability decreases first and then increase as the size of cluster increases; on the contrary, when the size of cluster keeps constant, the wettability decreases and then increase with the decrease of HI ratio, but when the size of water cluster is close to the threshold the HI ratio has little effect on the wettability.

Low floor mass transit vehicle

DOEpatents

Emmons, J Bruce [Beverly Hills, MI; Blessing, Leonard J [Rochester, MI

2004-02-03

A mass transit vehicle includes a frame structure that provides an efficient and economical approach to providing a low floor bus. The inventive frame includes a stiff roof panel and a stiff floor panel. A plurality of generally vertical pillars extend between the roof and floor panels. A unique bracket arrangement is disclosed for connecting the pillars to the panels. Side panels are secured to the pillars and carry the shear stresses on the frame. A unique seating assembly that can be advantageously incorporated into the vehicle taking advantage of the load distributing features of the inventive frame is also disclosed.

A novel high performance SemiSJ-CSTBT with p-pillar under the bottom of the trench gate

NASA Astrophysics Data System (ADS)

Yan, Jia; Hong, Chen; Ji, Tan; Shuojin, Lu; Yangjun, Zhu

2016-08-01

A novel high performance SemiSJ-CSTBT is proposed with the p-pillar under the bottom of the trench gate. The inserted p-pillar with the neighbouring n-drift region forms a lateral P/N junction, which can adjust the electric distribution in the forward-blocking mode to achieve a higher breakdown voltage compared to the conventional CSTBT. Also, the p-pillar can act as a hole collector at turn-off, which significantly enhances the turn-off speed and obtains a lower turn-off switching loss. Although the turn-off switching loss decreases as the depth of the p-pillar increases, there is no need for a very deep p-pillar. The associated voltage overshoot at turn-off increases dramatically with increasing the depth of p-pillar, which may cause destruction of the devices. Plus, this will add difficulty and cost to the manufacturing process of this new structure. Therefore, the proposed SemiSJ-CSTBT offers considerably better robustness compared to the conventional CSTBT and SJ-CSTBT. The simulation results show that the SemiSJ-CSTBT exhibits an increase in breakdown voltage by 160 V (13%) and a reduction of turn-off switching loss by approximately 15%. Project supported by the National Major Science and Technology Special Project of China (No. 2013ZX02305005-002) and the Major Program of the National Natural Science Foundation of China (No. 51490681).

Biomimetic Superhydrophobic Hollowed-Out Pyramid Surface Based on Self-Assembly.

PubMed

Luo, Weipeng; Yu, Bin; Xiao, Dingbang; Zhang, Meng; Wu, Xuezhong; Li, Guoxi

2018-05-16

In this paper, we present a periodic hollowed-out pyramid microstructure with excellent superhydrophobicity. In our approach, T-topping pillars and capillary-induced self-assembly methods were combined with the photolithography process to fabricate a hollowed-out pyramid structure. First, a wideband ultraviolet source without a filter was used to fabricate the T-topping pillars during the exposure process; then, the evaporation-induced assembly collapsed the pillars and formed the hollowed-out pyramid structure. Scanning electron microscopy images showed the microstructures of the prepared surface. The contact angle of the surface was 154°. The surface showed excellent high temperature and ultraviolet irradiation tolerance, and the contact angle of the surface barely changed when the temperature dropped. This excellent environmental durability of our superhydrophobic surface has potential applications for self-cleaning and friction drag reduction under water.

Pillars of Creation Revealed in 3-D

NASA Image and Video Library

2015-05-01

This video clip shows a visualisation of the three-dimensional structure of the Pillars of Creation within the star formation region Messier 16 (also called the Eagle Nebula). It is based on new observations of the object using the MUSE instrument on ESO’s Very Large Telescope in Chile. The pillars actually consist of several distinct pieces on either side of the star cluster NGC 6611. Credit: ESO/M. Kornmesser Read more: www.nasa.gov/image-feature/goddard/pillars-of-creation-re... NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

Deep proton writing of high aspect ratio SU-8 micro-pillars on glass

NASA Astrophysics Data System (ADS)

Ebraert, Evert; Rwamucyo, Ben; Thienpont, Hugo; Van Erps, Jürgen

2016-12-01

Deep proton writing (DPW) is a fabrication technology developed for the rapid prototyping of polymer micro-structures. We use SU-8, a negative resist, spincoated in a layer up to 720 μm-thick in a single step on borosilicate glass, for irradiation with a collimated 12 MeV energy proton beam. Micro-pillars with a slightly conical profile are irradiated in the SU-8 layer. We determine the optimal proton fluence to be 1.02 × 104 μm-2, with which we are able to repeatably achieve micro-pillars with a top-diameter of 138 ± 1 μm and a bottom-diameter of 151 ± 3 μm. The smallest fabricated pillars have a top-diameter of 57 ± 5 μm. We achieved a root-mean-square sidewall surface roughness between 19 nm and 35 nm for the fabricated micro-pillars, measured over an area of 5 × 63.7 μm. We briefly discuss initial testing of two potential applications of the fabricated micro-pillars. Using ∼100 μm-diameter pillars as waveguides for gigascale integration optical interconnect applications, has shown a 4.7 dB improvement in optical multimode fiber-to-fiber coupling as compared to the case where an air-gap is present between the fibers at the telecom wavelength of 1550 nm. The ∼140 μm-diameter pillars were used for mold fabrication with silicone casting. The resulting mold can be used for hydrogel casting, to obtain hydrogel replicas mimicking human tissue for in vitro bio-chemical applications.

Versatile assembly of p-carboxylatocalix[4]arene-O-alkyl ethers

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

Kennedy, Stuart; Teat, Simon J.; Dalgarno, Scott J.

Crystallisation of lower-rim tetra-O-alkylated p-carboxylatocalix[4]arenes from pyridine results in the formation of both bi-layer and pillar type supramolecular motifs. Full alkylation at the calixarene lower rim has significant influence over the supramolecular self-assembly motif, including preclusion of pyridine guest molecules from the calixarene cavity in the solid state.

Ancillary ligand-assisted assembly of C{sub 3}-symmetric 4,4′,4″-nitrilotribenzoic acid with divalent Zn{sup 2+} ions: Syntheses, topological structures, and photoluminescence properties

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

Cui, Li-Ting; Niu, Yan-Fei; Han, Jie, E-mail: chan@ouhk.edu.hk

4,4′,4″-nitrilotribenzoic acid (H{sub 3}L), a C{sub 3}-symmetric ligand, was found to self-assemble into two polymorphs driven by intermolecular hydrogen-bonding interactions. Reactions of this ligand with Zn{sup 2+} under solvothermal conditions resulted in four new coordination polymers bearing interesting structural motifs: [Zn{sub 2}(L){sub 2}(py){sub 2}]·2(H{sub 2}NMe{sub 2}){sup +}·DMF·2H{sub 2}O (1), [Zn{sub 2}(L)(H{sub 2}L)(bipy)]·1.5H{sub 2}O·Guest (2), [Zn{sub 2}(L){sub 2}(bipy)]·2(H{sub 2}NMe{sub 2}){sup +}·2DMF (3), and [Zn{sub 3}(L){sub 2}(bpa)]·2H{sub 2}O·Guest (4) (H{sub 3}L=4,4′,4′′-nitrilotribenzoic acid, DMF=dimethylformamide, py=pyridine, bipy=4,4′-bipyridine, bpa=1,2-bis(4-pyridyl)diazene). Single-crystal structural analysis revealed that compound 1 exhibits a rare example of twofold interpenetrating anionic 3D (3,3)-net framework containing helical channels, whereas in 2, the 3Dmore » pillar-layer structure generated from bipy-pillared Zn{sub 2}(L)(H{sub 2}L) layer is further reinforced by intermolecular hydrogen bonding among pairs of free –COOH units. Compound 3 shows an interesting entangled architecture of 2D→3D parallel polycatenation consisting five-coordinated Zn{sup 2+} ions. Compound 4 displays a 3D pillar-layer framework with trimeric Zn{sub 3}(CO{sub 2}){sub 6} serving as secondary building unit (SBU). The syntheses, structures, thermal stabilities, powder X-ray diffractions and solid-state photoluminescence properties for these crystalline materials have been carried out. In addition, supramolecular assembly of H{sub 3}L under solvothermal conditions will also be addressed. - Graphical abstract: Supramolecular assembly of 4,4′,4′′-nitrilotribenzoic acid and its ligand behavior toward Zn{sup 2+} were investigated, which exhibit two polymorphs of the free acid and four metal coordination polymers bearing interesting structural motifs. - Highlights: • Two polymorphs of H{sub 3}L showing different hydrogen-bonded network were obtained. • Tune over the structure of MOFs was achieved. • 1 has a 2-fold interpenetrating anionic 3D network containing helical channels. • Structures bearing free carboxylic acid (–COOH) unit are constructed in 2. • 3 represents a rare 2D+2D→3D catenation array containing five-coordinated Zn{sup 2+}.« less

Effects of magnetic fields on photoionized pillars and globules

NASA Astrophysics Data System (ADS)

Mackey, Jonathan; Lim, Andrew J.

2011-04-01

The effects of initially uniform magnetic fields on the formation and evolution of dense pillars and cometary globules at the boundaries of H II regions are investigated using 3D radiation-magnetohydrodynamics simulations. It is shown, in agreement with previous work, that a strong initial magnetic field is required to significantly alter the non-magnetized dynamics because the energy input from photoionization is so large that it remains the dominant driver of the dynamics in most situations. Additionally, it is found that for weak and medium field strengths an initially perpendicular field is swept into alignment with the pillar during its dynamical evolution, matching magnetic field observations of the 'Pillars of Creation' in M16 and also some cometary globules. A strong perpendicular magnetic field remains in its initial configuration and also confines the photoevaporation flow into a bar-shaped dense ionized ribbon which partially shields the ionization front and would be readily observable in recombination lines. A simple analytic model is presented to explain the properties of this bright linear structure. These results show that magnetic field strengths in star-forming regions can in principle be significantly constrained by the morphology of structures which form at the borders of H II regions.

Single macroscopic pillars as model system for bioinspired adhesives: influence of tip dimension, aspect ratio, and tilt angle.

PubMed

Micciché, Maurizio; Arzt, Eduard; Kroner, Elmar

2014-05-28

The goal of our study is to better understand the design parameters of bioinspired dry adhesives inspired by geckos. For this, we fabricated single macroscopic pillars of 400 μm diameter with different aspect ratios and different tip shapes (i.e., flat tips, spherical tips with different radii, and mushroom tips with different diameters). Tilt-angle-dependent adhesion measurements showed that although the tip shape of the pillars strongly influences the pull-off force, the pull-off strength is similar for flat and mushroom-shaped tips. We found no tilt-angle dependency of adhesion for spherical tip structures and, except for high tilt angle and low preload experiments, no tilt-angle effect for mushroom-tip pillars. For flat-tip pillars, we found a strong influence of tilt angle on adhesion, which decreased linearly with increasing aspect ratio. The experiments show that for the tested aspect ratios between 1 and 5, a linear decrease of tilt-angle dependency is found. The results of our studies will help to design bioinspired adhesives for application on smooth and rough surfaces.

Scattering of spermatozoa off cylindrical pillars

NASA Astrophysics Data System (ADS)

Bukatin, Anton; Lushi, Enkeleida; Kantsler, Vasily

2017-11-01

The motion of micro-swimmers in structured environments, even though crucial in processes such as in vivo and in vitro egg fertilization, is still not completely understood. We combine microfluidic experiments with mathematical modeling of 3D swimming near convex surfaces to quantify the dynamics of individual sperm cells in the proximity of cylindrical pillars. Our results show that the hydrodynamic and contact forces that account for the shape asymmetry and flagellar motion, are crucial in correctly describing the dynamics observed in the experiments. Last, we discuss how the size of the cylindrical obstacles determines whether the swimmers scatter off or get trapped circling the pillar.

Evaluation of kinematics and injuries to restrained occupants in far-side crashes using full-scale vehicle and human body models.

PubMed

Arun, Mike W J; Umale, Sagar; Humm, John R; Yoganandan, Narayan; Hadagali, Prasanaah; Pintar, Frank A

2016-09-01

The objective of the current study was to perform a parametric study with different impact objects, impact locations, and impact speeds by analyzing occupant kinematics and injury estimations using a whole-vehicle and whole-body finite element-human body model (FE-HBM). To confirm the HBM responses, the biofidelity of the model was validated using data from postmortem human surrogate (PMHS) sled tests. The biofidelity of the model was validated using data from sled experiments and correlational analysis (CORA). Full-scale simulations were performed using a restrained Global Human Body Model Consortium (GHBMC) model seated on a 2001 Ford Taurus model using a far-side lateral impact condition. The driver seat was placed in the center position to represent a nominal initial impact condition. A 3-point seat belt with pretensioner and retractor was used to restrain the GHBMC model. A parametric study was performed using 12 simulations by varying impact locations, impacting object, and impact speed using the full-scale models. In all 12 simulations, the principal direction of force (PDOF) was selected as 90°. The impacting objects were a 10-in.-diameter rigid vertical pole and a movable deformable barrier. The impact location of the pole was at the C-pillar in the first case, at the B-pillar in the second case, and, finally, at the A-pillar in the third case. The vehicle and the GHBMC models were defined an initial velocity of 35 km/h (high speed) and 15 km/h (low speed). Excursion of the head center of gravity (CG), T6, and pelvis were measured from the simulations. In addition, injury risk estimations were performed on head, rib cage, lungs, kidneys, liver, spleen, and pelvis. The average CORA rating was 0.7. The shoulder belt slipped in B- and C-pillar impacts but somewhat engaged in the A-pillar case. In the B-pillar case, the head contacted the intruding struck-side structures, indicating higher risk of injury. Occupant kinematics depended on interaction with restraints and internal structures-especially the passenger seat. Risk analysis indicated that the head had the highest risk of sustaining an injury in the B-pillar case compared to the other 2 cases. Higher lap belt load (3.4 kN) may correspond to the Abbreviated Injury Scale (AIS) 2 pelvic injury observed in the B-pillar case. Risk of injury to other soft anatomical structures varied with impact configuration and restraint interaction. The average CORA rating was 0.7. In general, the results indicated that the high-speed impacts against the pole resulted in severe injuries, higher excursions followed by low-speed pole, high-speed moving deformable barrier (MDB), and low-speed MDB impacts. The vehicle and occupant kinematics varied with different impact setups and the latter kinematics were likely influenced by restraint effectiveness. Increased restraint engagement increased the injury risk to the corresponding anatomic structure, whereas ineffective restraint engagement increased the occupant excursion, resulting in a direct impact to the struck-side interior structures.

Composite Pillars with a Tunable Interface for Adhesion to Rough Substrates

PubMed Central

2016-01-01

The benefits of synthetic fibrillar dry adhesives for temporary and reversible attachment to hard objects with smooth surfaces have been successfully demonstrated in previous studies. However, surface roughness induces a dramatic reduction in pull-off stresses and necessarily requires revised design concepts. Toward this aim, we introduce cylindrical two-phase single pillars, which are composed of a mechanically stiff stalk and a soft tip layer. Adhesion to smooth and rough substrates is shown to exceed that of conventional pillar structures. The adhesion characteristics can be tuned by varying the thickness of the soft tip layer, the ratio of the Young’s moduli and the curvature of the interface between the two phases. For rough substrates, adhesion values similar to those obtained on smooth substrates were achieved. Our concept of composite pillars overcomes current practical limitations caused by surface roughness and opens up fields of application where roughness is omnipresent. PMID:27997118

Porphyrin framework solids. Synthesis and structure of hybrid coordination polymers of tetra(carboxyphenyl)porphyrins and lanthanide-bridging ions.

PubMed

Muniappan, Sankar; Lipstman, Sophia; George, Sumod; Goldberg, Israel

2007-07-09

New types of porphyrin-based framework solids were constructed by reacting meso-tetra(3-carboxyphenyl)porphyrin and meso-tetra(4-carboxyphenyl)metalloporphyrins with common salts of lanthanide metal ions. The large size, high coordination numbers and strong affinity for oxo ligands of the latter, combined with favorable hydrothermal reaction conditions, allowed the formation of open three-dimensional single-framework architectures by coordination polymerization, in which the tetradentate porphyrin units are intercoordinated by multinuclear assemblies of the bridging metal ions. The latter serve as construction pillars of the supramolecular arrays, affording stable structures. Several modes of coordination polymerization were revealed by single-crystal X-ray diffraction. They differ by the spatial functionality of the porphyrin building blocks, the coordination patterns of the lanthanide-carboxylate assemblies, and the topology of the resulting frameworks. The seven new reported structures exhibit periodically spaced 0.4-0.6 nm wide channel voids that perforate the respective crystalline polymeric architectures and are accessible to solvent components. Materials based on the m-carboxyphenyl derivative reveal smaller channels than those based on the p-carboxyphenyl analogues. An additional complex of the former with a smaller third-row transition metal (Co) is characterized by coordination connectivity in two dimensions only. Thermal and powder-diffraction analyses confirm the stability of the lanthanide-TmCPP (TmCPP=tetra(m-carboxyphenyl)porphyrin) frameworks.

Effects of Solid Fraction on Droplet Wetting and Vapor Condensation: A Molecular Dynamic Simulation Study.

PubMed

Gao, Shan; Liao, Quanwen; Liu, Wei; Liu, Zhichun

2017-10-31

Recently, numerous studies focused on the wetting process of droplets on various surfaces at a microscale level. However, there are a limited number of studies about the mechanism of condensation on patterned surfaces. The present study performed the dynamic wetting behavior of water droplets and condensation process of water molecules on substrates with different pillar structure parameters, through molecular dynamic simulation. The dynamic wetting results indicated that droplets exhibit Cassie state, PW state, and Wenzel state successively on textured surfaces with decreasing solid fraction. The droplets possess a higher static contact angle and a smaller spreading exponent on textured surfaces than those on smooth surfaces. The condensation processes, including the formation, growth, and coalescence of a nanodroplet, are simulated and quantitatively recorded, which are difficult to be observed by experiments. In addition, a wetting transition and a dewetting transition were observed and analyzed in condensation on textured surfaces. Combining these simulation results with previous theoretical and experimental studies will guide us to understand the hypostasis and mechanism of the condensation more clearly.

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

Killian, Christopher; Metzler, Rebecca; Gong, Y. U. T.

Sea urchin teeth are remarkable and complex calcite structures, continuously growing at the forming end and self-sharpening at the mature grinding tip. The calcite (CaCO{sub 3}) crystals of tooth components, plates, fibers, and a high-Mg polycrystalline matrix, have highly co-oriented crystallographic axes. This ability to co-orient calcite in a mineralized structure is shared by all echinoderms. However, the physico-chemical mechanism by which calcite crystals become co-oriented in echinoderms remains enigmatic. Here, we show differences in calcite c-axis orientations in the tooth of the purple sea urchin (Strongylocentrotus purpuratus), using high-resolution X-ray photoelectron emission spectromicroscopy (X-PEEM) and microbeam X-ray diffraction ({mu}XRD).more » All plates share one crystal orientation, propagated through pillar bridges, while fibers and polycrystalline matrix share another orientation. Furthermore, in the forming end of the tooth, we observe that CaCO{sub 3} is present as amorphous calcium carbonate (ACC). We demonstrate that co-orientation of the nanoparticles in the polycrystalline matrix occurs via solid-state secondary nucleation, propagating out from the previously formed fibers and plates, into the amorphous precursor nanoparticles. Because amorphous precursors were observed in diverse biominerals, solid-state secondary nucleation is likely to be a general mechanism for the co-orientation of biomineral components in organisms from different phyla.« less

Unique coordination of pyrazine in T[Ni(CN){sub 4}].2pyz with T=Mn, Zn, Cd

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

Lemus-Santana, A.A.; Rodriguez-Hernandez, J.; Castillo, L.F. del, E-mail: lfelipe@servidor.unam.m

2009-04-15

The materials under study, T[Ni(CN){sub 4}].2pyz with T=Mn, Zn, Cd, were prepared by separation of T[Ni(CN){sub 4}] layers in citrate aqueous solution to allow the intercalation of the pyrazine molecules. The obtained solids were characterized from chemical analyses, X-ray diffraction, infrared, Raman, thermogravimetry, UV-Vis, magnetic and adsorption data. Their crystal structure was solved from ab initio using direct methods and then refined by the Rietveld method. A unique coordination for pyrazine to metal centers at neighboring layers was observed. The pyrazine molecule is found forming a bridge between Ni and T atoms, quite different from the proposed structures for T=Fe,more » Ni where it remains coordinated to two T atoms to form a vertical pillar between neighboring layers. The coordination of pyrazine to both Ni and T atoms minimizes the material free volume and leads to form a hydrophobic framework. On heating the solids remain stable up to 140 deg. C. No CO{sub 2} and H{sub 2} adsorption was observed in the small free spaces of their frameworks. - Graphical abstract: Framework for T[Ni(CN){sub 4}].2pyz with T=Mn, Zn, Cd.« less

Mechanism of calcite co-orientation in the sea urchin tooth.

PubMed

Killian, Christopher E; Metzler, Rebecca A; Gong, Y U T; Olson, Ian C; Aizenberg, Joanna; Politi, Yael; Wilt, Fred H; Scholl, Andreas; Young, Anthony; Doran, Andrew; Kunz, Martin; Tamura, Nobumichi; Coppersmith, Susan N; Gilbert, P U P A

2009-12-30

Sea urchin teeth are remarkable and complex calcite structures, continuously growing at the forming end and self-sharpening at the mature grinding tip. The calcite (CaCO(3)) crystals of tooth components, plates, fibers, and a high-Mg polycrystalline matrix, have highly co-oriented crystallographic axes. This ability to co-orient calcite in a mineralized structure is shared by all echinoderms. However, the physico-chemical mechanism by which calcite crystals become co-oriented in echinoderms remains enigmatic. Here, we show differences in calcite c-axis orientations in the tooth of the purple sea urchin ( Strongylocentrotus purpuratus ), using high-resolution X-ray photoelectron emission spectromicroscopy (X-PEEM) and microbeam X-ray diffraction (muXRD). All plates share one crystal orientation, propagated through pillar bridges, while fibers and polycrystalline matrix share another orientation. Furthermore, in the forming end of the tooth, we observe that CaCO(3) is present as amorphous calcium carbonate (ACC). We demonstrate that co-orientation of the nanoparticles in the polycrystalline matrix occurs via solid-state secondary nucleation, propagating out from the previously formed fibers and plates, into the amorphous precursor nanoparticles. Because amorphous precursors were observed in diverse biominerals, solid-state secondary nucleation is likely to be a general mechanism for the co-orientation of biomineral components in organisms from different phyla.

Subwavelength micropillar array terahertz lasers.

PubMed

Krall, Michael; Brandstetter, Martin; Deutsch, Christoph; Detz, Hermann; Andrews, Aaron Maxwell; Schrenk, Werner; Strasser, Gottfried; Unterrainer, Karl

2014-01-13

We report on micropillar-based terahertz lasers with active pillars that are much smaller than the emission wavelength. These micropillar array lasers correspond to scaled-down band-edge photonic crystal lasers forming an active photonic metamaterial. In contrast to photonic crystal lasers which use significantly larger pillar structures, lasing emission is not observed close to high-symmetry points in the photonic band diagram, but in the effective medium regime. We measure stimulated emission at 4 THz for micropillar array lasers with pillar diameters of 5 µm. Our results not only demonstrate the integration of active subwavelength optics in a terahertz laser, but are also an important step towards the realization of nanowire-based terahertz lasers.

Directing the breathing behavior of pillared-layered metal-organic frameworks via a systematic library of functionalized linkers bearing flexible substituents.

PubMed

Henke, Sebastian; Schneemann, Andreas; Wütscher, Annika; Fischer, Roland A

2012-06-06

Flexible metal-organic frameworks (MOFs), also referred to as soft porous crystals (SPCs), show reversible structural transitions dependent on the nature and quantity of adsorbed guest molecules. In recent studies it has been reported that covalent functionalization of the organic linker can influence or even integrate framework flexibility ("breathing") in MOFs. However, rational fine-tuning of such responsive properties is very desirable but challenging as well. Here we present a powerful approach for the targeted manipulation of responsiveness and framework flexibility of an important family of pillared-layered MOFs based on the parent structure [Zn(2)(bdc)(2)(dabco)](n) (bdc = 1,4-benzenedicarboxylate; dabco = 1,4-diazabicyclo[2.2.2]octane). A library of functionalized bdc-type linkers (fu-bdc), which bear additional dangling side groups at different positions of the benzene core (alkoxy groups of varying chain length with diverse functionalities and polarity), was generated. Synthesis of the materials [Zn(2)(fu-bdc)(2)(dabco)](n) yields the respective collection of highly responsive MOFs. The parent MOF is only weakly flexible; however, the substituted frameworks of [Zn(2)(fu-bdc)(2)(dabco)](n) contract drastically upon guest removal and expand again upon adsorption of DMF (N,N-dimethylformamide), EtOH, or CO(2), etc., while N(2) is hardly adsorbed and does not open the narrow-pored form. These "breathing" dynamics are attributed to the dangling side chains that act as immobilized "guests", which interact with mobile guest molecules as well as with themselves and with the framework backbone. The structural details of the guest-free, contracted form and the gas sorption behavior (phase transition pressure, hysteresis loop) are highly dependent on the nature of the substituent at the linker and can therefore be adjusted using our approach. Combining our library of functionalized linkers with the concept of mixed-component MOFs (solid solutions) offers very rich additional dimensions of tailoring the structural dynamics and responsiveness. Implementation of two differently functionalized linkers in varying ratios yields multicomponent single-phased [Zn(2)(fu-bdc')(2x)(fu-bdc″)(2-2x)(dabco)](n) MOFs (0 < x < 1) of increased inherent complexity, which feature a non-linear dependence of their gas sorption properties on the applied ratio of components. Hence, the responsive behavior of such pillared-layered MOFs can be extensively tuned via an intelligent combination of functionalized linkers.

Development of a shear stress sensor to analyse the influence of polymers on the turbulent wall shear stress.

PubMed

Nottebrock, Bernardo; Grosse, Sebastian; Schröder, Wolfgang

2011-05-11

The drag reducing effect of polymers in a channel flow is well known and it is assumed that the polymer filaments interfere with the turbulent structures in the very near-wall flow. To analyse their precise effect, a micro-pillar shear stress sensor (MPS³) measurement system is developed which allows the detection of wall shear stress at high spatial and temporal resolutions. Different manufacturing techniques for the required micro-pillars are discussed and their influence on the flow is investigated evidencing the non-intrusive character of the pillars. Subsequently, a complete calibration is presented to relate the recorded deflection to wall shear stress values and to assure the correct detection over the whole expected frequency spectrum. A feasibility study about the ability to visualize the two-dimensional wall shear stress distribution completes the discussion about the validity of MPS³. In the last step, the drag reduction of a polymer filament grafted on a micro-pillar compared to a plain pillar and the application of MPS³ in an ocean-type polymer solution are investigated. The results confirm the expected behaviour found in the literature.

The role of SiGe buffer in growth and relaxation of Ge on free-standing Si(001) nano-pillars.

PubMed

Zaumseil, P; Kozlowski, G; Schubert, M A; Yamamoto, Y; Bauer, J; Schülli, T U; Tillack, B; Schroeder, T

2012-09-07

We study the growth and relaxation processes of Ge nano-clusters selectively grown by chemical vapor deposition on free-standing 90 nm wide Si(001) nano-pillars with a thin Si(0.23)Ge(0.77) buffer layer. We found that the dome-shaped SiGe layer with a height of about 28 nm as well as the Ge dot deposited on top of it partially relaxes, mainly by elastic lattice bending. The Si nano-pillar shows a clear compliance behavior-an elastic response of the substrate on the growing film-with the tensile strained top part of the pillar. Additional annealing at 800 °C leads to the generation of misfit dislocation and reduces the compliance effect significantly. This example demonstrates that despite the compressive strain generated due to the surrounding SiO(2) growth mask it is possible to realize an overall tensile strain in the Si nano-pillar and following a compliant substrate effect by using a SiGe buffer layer. We further show that the SiGe buffer is able to improve the structural quality of the Ge nano-dot.

Study on structural characteristics of pillared clay modified phosphate fertilizers and its increase efficiency mechanism*

PubMed Central

Wu, Ping-xiao; Liao, Zong-wen

2005-01-01

Three types of new high-efficiency phosphate fertilizers were made when pillared clays at certain proportions were added into ground phosphate rock. Chemical analyses showed that their soluble phosphorus content decreased more than that of superphosphate. Pot experiment showed that, under equal weights, the new fertilizers increased their efficiency by a large margin over that of superphosphate. Researches on their structures by means of XRD, IR and EPR spectrum revealed that their crystal structures changed considerably, improving their activity and preventing the fixation of available phosphorus in the soil, and consequently, greatly improved the bioavailability and became the main cause of the increase of biomass. PMID:15682504

Nonmonotonic fluctuation spectra of membranes pinned or tethered discretely to a substrate.

PubMed

Merath, Rolf-Jürgen; Seifert, Udo

2006-01-01

The thermal fluctuation spectrum of a fluid membrane coupled harmonically to a solid support by an array of tethers is calculated. For strong tethers, this spectrum exhibits nonmonotonic, anisotropic behavior with a relative maximum at a wavelength about twice the tether distance. The root-mean-square displacement is evaluated to estimate typical membrane displacements. Possible applications cover pillar-supported or polymer-tethered membranes.

Intermolecular interactions between imidazole derivatives intercalated in layered solids. Substituent group effect

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

González, M.; Lemus-Santana, A.A.; Rodríguez-Hernández, J.

2013-08-15

This study sheds light on the intermolecular interactions between imidazole derive molecules (2-methyl-imidazole, 2-ethyl-imidazole and benzimidazole) intercalated in T[Ni(CN){sub 4}] layers to form a solid of formula unit T(ImD){sub 2}[Ni(CN){sub 4}]. These hybrid inorganic–organic solids were prepared by soft chemical routes and their crystal structures solved and refined from X-ray powder diffraction data. The involved imidazole derivative molecules were found coordinated through the pyridinic N atom to the axial positions for the metal T in the T[Ni(CN){sub 4}] layer. In the interlayers region ligand molecules from neighboring layers remain stacked in a face-to-face configuration through dipole–dipole and quadrupole–quadrupole interactions. Thesemore » intermolecular interactions show a pronounced dependence on the substituent group and are responsible for an ImD-pillaring concatenation of adjacent layers. This is supported by the structural information and the recorded magnetic data in the 2–300 K temperature range. The samples containing Co and Ni are characterized by presence of spin–orbit coupling and pronounced temperature dependence for the effective magnetic moment except for 2-ethyl-imidazole related to the local distortion for the metal coordination environment. For this last one ligand a weak ferromagnetic ordering ascribed to a super-exchange interaction between T metals from neighboring layers through the ligands π–π interaction was detected. - Graphical abstract: In the interlayers region imidazole derivative molecules are oriented according to their dipolar and quadrupolar interactions and minimizing the steric impediment. Highlights: • Imidazole derivatives intercalation compounds. • Intermolecular interaction between intercalated imidazole derivatives. • Hybrid inorganic–organic solids. • Pi–pi interactions and ferromagnetic coupling. • Dipolar and quadrupolar interactions between intercalated imidazole derivatives.« less

The molecular transport and intercalation of guest molecules into hydrogen-bonded metal-organic frameworks (HMOFs)

NASA Astrophysics Data System (ADS)

Hogan, Greg Anthony

The process of molecular transport and intercalation has been widely studied for many years, resulting in the discovery of molecular frameworks that are capable of hosting guest molecules or ions. Layered and porous metal-organic frameworks (MOFs) have been found to have applications in the field of catalysis, storage, separations, and ion-exchange. More recently, molecular components with peripheral hydrogen-bonding moieties have been used to affect the synthesis of hydrogen-bonded metal-organic frameworks (HMOFs) as an alternative to MOFs, which are interconnected via coordinate-covalent bonds. While MOFs are perhaps stronger materials, HMOFs have the advantage of being easily modifiable and more flexible. Because HMOFs have not been extensively studied for their ability to host molecules, and because their ability to withstand guest loss and guest exchange is essentially unknown, here we report the synthesis and molecular transport properties of both close-packed and porous HMOFs. Layered materials can mimic the behavior of naturally occurring clays, where guest molecules are absorbed and the layer will expand to accommodate the entering guest molecule. We have created a clay mimic composed of a metal pyridine-dicarboxylates and ammonium counterions (a layered HMOF), which is suitable for studying the ability of such materials to absorb guest molecules. We can control the distance of the interlayer region, as well as the chemical nature (hydrophobic or hydrophilic) by varying the organic amine. The metal complex contains axial water ligands that are replaceable, and such ligand exchange has precedence in coordination polymer (MOF) systems, and has been termed "coordinative intercalation". Using the synthesized layered material we examined the process of intercalation, having chosen a variety of guest molecules ranging from alkyl to aryl molecules, each of which have substituents varying in size, shape and electronics. The first set of guest molecules are non-coordinating and are theoretically capable of entering the layer and anchoring freely through the use of non-covalent interactions. The second set of guest molecules contain a pyridine moiety that can exchange with the coordinated water ligand through coordinative-intercalation. The products have been characterized by TGA, DSC, UV-Vis, and powder XRD. Further work was dedicated to examining porous materials, which were created using organic diamines, rather than simple primary amines, as starting materials. The resulting diammonium cations act as pillars, forming open channels. The predefined channel dimensions allow the insertion of specific sized guest molecules. The walls of the channel are close-packed, so that in theory guest molecules can travel in one direction through the solid. Using the synthesized pillared structure we investigated guest inclusion and selectivity through the process of co-crystallization. The stability of the pillared structure in the absence of guests is also reported, as well as the potential for the empty pillared structure to withstand guest re-insertion and removal.

Characteristics and self-cleaning effect of the transparent super-hydrophobic film having nanofibers array structures

NASA Astrophysics Data System (ADS)

Lee, Kyungjun; Lyu, Sungnam; Lee, Sangmin; Kim, Youn Sang; Hwang, Woonbong

2010-09-01

Transparent super-hydrophobic films were fabricated using the PDMS method and silane process, based on anodization in phosphoric acid. Contact angle tests were performed to determine the contact angle of each film according to the anodizing time. Transmittance tests also were performed to obtain the transparency of each TPT (trimethylolpropane propoxylate triacrylate) replica film according to the anodizing time. The contact angle was determined by studying the drop shape, and the transmittance was measured using a UV-spectrometer. The contact angle increases with increasing anodizing time, because increasing pillar length can trap more air between the TPT replica film and a drop of water. The transmittance falls with increasing anodizing time because the increasing pillar length causes a scattering effect. This study shows that the pillar length and transparency are inversely proportional. The TPT replica film having nanofibers array structures was better than other films in aspect of self-cleaning by doing quantitative experimentation.

Preparation of Tunable 3D Pillared Carbon Nanotube-Graphene Networks for High-Performance Capacitance

DTIC Science & Technology

2011-01-01

nanotubes ( CNTs ) and two-dimensional (2D) single-atomic layer graphene, have been demonstrated to show superior thermal, electrical, and mechanical...and the much weaker van der Waals interaction in the transverse direction between the layers, how- ever, CNTs and graphene exhibit strong direction...structure are governed by the minimum interpillar distance (MIPD) and the CNT -pillar length (PL) (Figure 1a). Some successes in fabricating randomly

Hubble Goes High Def to Revisit the Iconic 'Pillars of Creation'

NASA Image and Video Library

2017-12-08

This NASA Hubble Space Telescope image, taken in near-infrared light, transforms the pillars into eerie, wispy silhouettes, which are seen against a background of myriad stars. The near-infrared light can penetrate much of the gas and dust, revealing stars behind the nebula as well as hidden away inside the pillars. Some of the gas and dust clouds are so dense that even the near-infrared light cannot penetrate them. New stars embedded in the tops of the pillars, however, are apparent as bright sources that are unseen in the visible image. The ghostly bluish haze around the dense edges of the pillars is material getting heated up by the intense ultraviolet radiation from a cluster of young, massive stars and evaporating away into space. The stellar grouping is above the pillars and cannot be seen in the image. At the top edge of the left-hand pillar, a gaseous fragment has been heated up and is flying away from the structure, underscoring the violent nature of star-forming regions. Astronomers used filters that isolate the light from newly formed stars, which are invisible in the visible-light image. At these wavelengths, astronomers are seeing through the pillars and even through the back wall of the nebula cavity and can see the next generations of stars just as they're starting to emerge from their formative nursery. Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA) Read more: 1.usa.gov/1HGfkqr NASA image use policy. NASA Goddard Space Flight Center enables NASA’s mission through four scientific endeavors: Earth Science, Heliophysics, Solar System Exploration, and Astrophysics. Goddard plays a leading role in NASA’s accomplishments by contributing compelling scientific knowledge to advance the Agency’s mission. Follow us on Twitter Like us on Facebook Find us on Instagram

OT1_nschneid_1: Pillars of creation: physical origin and connection to star formation

NASA Astrophysics Data System (ADS)

Schneider, N.

2010-07-01

Herschel SPIRE/PACS photometry observations performed within the HOBYS (Herschel imaging survey of OB Young Stellar objects) key program have revealed a wealth of interesting structures in high-mass star forming regions. The most spectacular of those are 'pillars' and 'globules'. These features -- partly known from Hubble Space telescope or Spitzer images -- are formed due to photoevaporation at the interface between a molecular cloud and an HII region, and are thus intimately linked to high-mass star formation. The process of how these pillars are created, and under which conditions low- or high-mass stars form within them, are not yet clear. Classical approaches (e.g. Rayleigh-Taylor) can not explain pillar formation, so we have embarked upon a dedicated project to fully simulate pillars and globules using the (magneto)-hydrodynamic code HERACLES that comprises gravity and ionization. The model is intended to be coupled with a radiative transfer photon dominated region code (KOSMA-tau). We propose here to make use of the Herschel spectroscopy capacities to map/make single pointings, in a number of atomic and molecular lines, of selected pillars and globules in three different regions (Rosette, Cygnus, M16), spanning a large range in UV intensity and density. We intend to observe the important cooling lines of [CII] at 158 micron and [OI] at 63 and 145 micron with PACS, the [CI] finestructure lines at 370 and 609 micron and the mid-to high-J CO and HCO+ ladder with the SPIRE FTS. Spectrally resolved [CII] mapping with HIFI is also required to derive the velocity information. These observations will be compared to the large existing complementary data set for each source, to study the physics of pillars and will additionally serve as input for the models, to ultimately explain pillar formation and star formation within them.

Globules and pillars in Cygnus X. I. Herschel far-infrared imaging of the Cygnus OB2 environment

NASA Astrophysics Data System (ADS)

Schneider, N.; Bontemps, S.; Motte, F.; Blazere, A.; André, Ph.; Anderson, L. D.; Arzoumanian, D.; Comerón, F.; Didelon, P.; Di Francesco, J.; Duarte-Cabral, A.; Guarcello, M. G.; Hennemann, M.; Hill, T.; Könyves, V.; Marston, A.; Minier, V.; Rygl, K. L. J.; Röllig, M.; Roy, A.; Spinoglio, L.; Tremblin, P.; White, G. J.; Wright, N. J.

2016-06-01

The radiative feedback of massive stars on molecular clouds creates pillars, globules and other features at the interface between the H II region and molecular cloud. Optical and near-infrared observations from the ground as well as with the Hubble or Spitzer satellites have revealed numerous examples of such cloud structures. We present here Herschel far-infrared observations between 70 μm and 500 μm of the immediate environment of the rich Cygnus OB2 association, performed within the Herschel imaging survey of OB Young Stellar objects (HOBYS) program. All of the observed irradiated structures were detected based on their appearance at 70 μm, and have been classified as pillars, globules, evaporating gasous globules (EGGs), proplyd-like objects, and condensations. From the 70 μm and 160 μm flux maps, we derive the local far-ultraviolet (FUV) field on the photon dominated surfaces. In parallel, we use a census of the O-stars to estimate the overall FUV-field, that is 103-104 G0 (Habing field) close to the central OB cluster (within 10 pc) and decreases down to a few tens G0, in a distance of 50 pc. From a spectral energy distribution (SED) fit to the four longest Herschel wavelengths, we determine column density and temperature maps and derive masses, volume densities and surface densities for these structures. We find that the morphological classification corresponds to distinct physical properties. Pillars and globules are massive (~500 M⊙) and large (equivalent radius r ~ 0.6 pc) structures, corresponding to what is defined as "clumps" for molecular clouds. EGGs and proplyd-likeobjects are smaller (r ~ 0.1 and 0.2 pc) and less massive (~10 and ~30 M⊙). Cloud condensations are small (~0.1 pc), have an average mass of 35 M⊙, are dense (~6 × 104 cm-3), and can thus be described as molecular cloud "cores". All pillars and globules are oriented toward the Cyg OB2 association center and have the longest estimated photoevaporation lifetimes, a few million years, while all other features should survive less than a million years. These lifetimes are consistent with that found in simulations of turbulent, UV-illuminated clouds. We propose a tentative evolutionary scheme in which pillars can evolve into globules, which in turn then evolve into EGGs, condensations and proplyd-like objects. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.

Solvent-free synthesis of new metal phosphites with double-layered, pillared-layered, and framework structures

NASA Astrophysics Data System (ADS)

Liu, Lin; Zhang, Wei; Shi, Zhonghua; Chen, Yaoqiang; Lin, Zhien

2014-12-01

Three new metal phosphites, formulated as (H3O)2·Mn2(HPO3)3 (1), Co(bpy) (H2O) (HPO3) (2), and H2tmpda·Zn3(HPO3)4 (3), have been synthesized under solvent-free conditions, where bpy = 4,4‧-bipyridine, and tmpda = N,N,N‧,N‧-tetramethyl-1,3-propanediamine. Compound 1 has a double-layered structure with a thickness of 5.68 Å. Compound 2 has an inorganic-organic hybrid framework with cobalt phosphite layers pillared by bpy ligands. Compound 3 has a three-dimensional open-framework structure containing 8-ring channels. The temperature dependence of the magnetic susceptibility of compounds 1 and 2 were also investigated.

Experimental and Numerical Investigation on the Bearing and Failure Mechanism of Multiple Pillars Under Overburden

NASA Astrophysics Data System (ADS)

Zhou, Zilong; Chen, Lu; Zhao, Yuan; Zhao, Tongbin; Cai, Xin; Du, Xueming

2017-04-01

To reveal the mechanical response of a multi-pillar supporting system under external loads, compressive tests were carried out on single-pillar and double-pillar specimens. The digital speckle correlation method and acoustic emission technique were applied to record and analyse information of the deformation and failure processes. Numerical simulations with the software programme PFC2D were also conducted. In the compressive process of the double-pillar system, if both individual pillars have the same mechanical properties, each pillar deforms similarly and reaches the critical stable state almost simultaneously by sharing equal loads. If the two individual pillars have different mechanical properties, the pillar with higher elastic modulus or lower strength would be damaged and lose its bearing capacity firstly. The load would then be transferred to the other pillar under a load redistribution process. When the pillar with higher strength is strong enough, the load carried by the pillar system would increase again. However, the maximum bearing load of the double-pillar system is smaller than the sum of peak load of individual pillars. The study also indicates that the strength, elastic modulus, and load state of pillars all influence the supporting capacity of the pillar system. In underground space engineering, the appropriate choice of pillar dimensions and layout may play a great role in preventing the occurrence of cascading pillar failure.

Engineering biomimetic hair bundle sensors for underwater sensing applications

NASA Astrophysics Data System (ADS)

Kottapalli, Ajay Giri Prakash; Asadnia, Mohsen; Karavitaki, K. Domenica; Warkiani, Majid Ebrahimi; Miao, Jianmin; Corey, David P.; Triantafyllou, Michael

2018-05-01

We present the fabrication of an artificial MEMS hair bundle sensor designed to approximate the structural and functional principles of the flow-sensing bundles found in fish neuromast hair cells. The sensor consists of micro-pillars of graded height connected with piezoelectric nanofiber "tip-links" and encapsulated by a hydrogel cupula-like structure. Fluid drag force actuates the hydrogel cupula and deflects the micro-pillar bundle, stretching the nanofibers and generating electric charges. These biomimetic sensors achieve an ultrahigh sensitivity of 0.286 mV/(mm/s) and an extremely low threshold detection limit of 8.24 µm/s. A complete version of this paper has been published [1].

High acidity unilamellar zeolite MCM-56 and its pillared and delaminated derivatives.

PubMed

Gil, Barbara; Makowski, Wacław; Marszalek, Bartosz; Roth, Wieslaw J; Kubu, Martin; Čejka, Jiři; Olejniczak, Zbigniew

2014-07-21

The unilamellar form of zeolite MWW, MCM-56, which is obtained by direct hydrothermal synthesis has been studied with regard to acidity and porosity in its original and post-synthesis modified pillared and delaminated forms. The acidity measured by FTIR was found to be only slightly lower than the highly active 3-D MWW forms, MCM-22 and MCM-49. Pivalonitrile adsorption, which is a measure of spatial openness, showed 50% accessibility vs. <30% for MCM-22/49. It highlights the potential of MCM-56 as a layered material with increased access to acid sites because it does not entail laborious post-synthesis modification. Swelling, pillaring and delamination of MCM-56 are facile but result in a reduction in the number of Brønsted acid sites (BAS) while increasing accessibility to pivalonitrile. The delamination procedure involving sonication and acidification of the highly basic mother liquor produces the most visible increase in surface area and access to all BAS. The accompanying doubling of the solid yield and the decrease in absolute number of BAS suggest significant precipitation of dissolved silica generated during swelling and sonication in high pH medium. The viability of separating surfactant covered layers upon sonication with the consequence of exposing hydrophobic hydrocarbon tails to aqueous environment is addressed.

Insect adhesion on rough surfaces: analysis of adhesive contact of smooth and hairy pads on transparent microstructured substrates

PubMed Central

Zhou, Yanmin; Robinson, Adam; Steiner, Ullrich; Federle, Walter

2014-01-01

Insect climbing footpads are able to adhere to rough surfaces, but the details of this capability are still unclear. To overcome experimental limitations of randomly rough, opaque surfaces, we fabricated transparent test substrates containing square arrays of 1.4 µm diameter pillars, with variable height (0.5 and 1.4 µm) and spacing (from 3 to 22 µm). Smooth pads of cockroaches (Nauphoeta cinerea) made partial contact (limited to the tops of the structures) for the two densest arrays of tall pillars, but full contact (touching the substrate in between pillars) for larger spacings. The transition from partial to full contact was accompanied by a sharp increase in shear forces. Tests on hairy pads of dock beetles (Gastrophysa viridula) showed that setae adhered between pillars for larger spacings, but pads were equally unable to make full contact on the densest arrays. The beetles' shear forces similarly decreased for denser arrays, but also for short pillars and with a more gradual transition. These observations can be explained by simple contact models derived for soft uniform materials (smooth pads) or thin flat plates (hairy-pad spatulae). Our results show that microstructured substrates are powerful tools to reveal adaptations of natural adhesives for rough surfaces. PMID:24990289

Insect adhesion on rough surfaces: analysis of adhesive contact of smooth and hairy pads on transparent microstructured substrates.

PubMed

Zhou, Yanmin; Robinson, Adam; Steiner, Ullrich; Federle, Walter

2014-09-06

Insect climbing footpads are able to adhere to rough surfaces, but the details of this capability are still unclear. To overcome experimental limitations of randomly rough, opaque surfaces, we fabricated transparent test substrates containing square arrays of 1.4 µm diameter pillars, with variable height (0.5 and 1.4 µm) and spacing (from 3 to 22 µm). Smooth pads of cockroaches (Nauphoeta cinerea) made partial contact (limited to the tops of the structures) for the two densest arrays of tall pillars, but full contact (touching the substrate in between pillars) for larger spacings. The transition from partial to full contact was accompanied by a sharp increase in shear forces. Tests on hairy pads of dock beetles (Gastrophysa viridula) showed that setae adhered between pillars for larger spacings, but pads were equally unable to make full contact on the densest arrays. The beetles' shear forces similarly decreased for denser arrays, but also for short pillars and with a more gradual transition. These observations can be explained by simple contact models derived for soft uniform materials (smooth pads) or thin flat plates (hairy-pad spatulae). Our results show that microstructured substrates are powerful tools to reveal adaptations of natural adhesives for rough surfaces.

Photocatalytic and adsorption properties of TiO2-pillared montmorillonite obtained by hydrothermally activated intercalation of titanium polyhydroxo complexes

PubMed Central

Ovchinnikov, Nikolay L; Karasev, Nikita S; Kochkina, Nataliya E; Agafonov, Alexander V; Vinogradov, Alexandr V

2018-01-01

We report on a new approach for the synthesis of TiO2-pillared montmorillonite, where the pillars exhibit a high degree of crystallinity (nanocrystals) representing a mixture of anatase and rutile phases. The structures exhibit improved adsorption and photocatalytic activity as a result of hydrothermally activated intercalation of titanium polyhydroxo complexes (i.e., TiCl4 hydrolysis products) in a solution with a concentration close to the sol formation limit. The materials, produced at various annealing temperatures from the intercalated samples, were characterized by infrared spectroscopy, differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA), X-ray diffraction, dynamic light scattering (DLS) measurements, and liquefied nitrogen adsorption/desorption. The photocatalytic activity of the TiO2-pillared materials was studied using the degradation of anionic (methyl orange, MO) and cationic (rhodamine B, RhB) dyes in water under UV irradiation. The combined effect of adsorption and photocatalysis resulted in removal of 100% MO and 97.5% RhB (with an initial concentration of 40 mg/L and a photocatalyst-sorbent concentration of 1 g/L) in about 100 minutes. The produced TiO2-pillared montmorillonite showed increased photocatalytic activity as compared to the commercially available photocatalyst Degussa P25. PMID:29515950

Porous Structures in Stacked, Crumpled and Pillared Graphene-Based 3D Materials.

PubMed

Guo, Fei; Creighton, Megan; Chen, Yantao; Hurt, Robert; Külaots, Indrek

2014-01-01

Graphene, an atomically thin material with the theoretical surface area of 2600 m 2 g -1 , has great potential in the fields of catalysis, separation, and gas storage if properly assembled into functional 3D materials at large scale. In ideal non-interacting ensembles of non-porous multilayer graphene plates, the surface area can be adequately estimated using the simple geometric law ~ 2600 m 2 g -1 /N, where N is the number of graphene sheets per plate. Some processing operations, however, lead to secondary plate-plate stacking, folding, crumpling or pillaring, which give rise to more complex structures. Here we show that bulk samples of multilayer graphene plates stack in an irregular fashion that preserves the 2600/N surface area and creates regular slot-like pores with sizes that are multiples of the unit plate thickness. In contrast, graphene oxide deposits into films with massive area loss (2600 to 40 m 2 g -1 ) due to nearly perfect alignment and stacking during the drying process. Pillaring graphene oxide sheets by co-deposition of colloidal-phase particle-based spacers has the potential to partially restore the large monolayer surface. Surface areas as high as 1000 m 2 g -1 are demonstrated here through colloidal-phase deposition of graphene oxide with water-dispersible aryl-sulfonated ultrafine carbon black as a pillaring agent.

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

Ren, Yixia, E-mail: renyixia1@163.com; Chai, Hongmei; Tang, Long

Three novel coordination polymers, namely, [Cd(2-Hstp)(1,4-bbi)(H{sub 2}O){sub 2}]·3H{sub 2}O (1), [Cd{sub 1.5}(2-stp)(1,4-bbi)(H{sub 2}O){sub 2}]·H{sub 2}O (2) and [Zn{sub 2}(2-stp)(μ{sub 2}-OH)(1,4-bbi){sub 1.5}(H{sub 2}O)]·6H{sub 2}O (3) (2-H{sub 3}stp is equal to 2-sulfoterephthalate and 1,4-bisbenzimidazole is equal to 1,4-bbi), have been synthesized by hydrothermal reaction. The structural analyses show that 1 and 2 possess different structural features despite the same raw materials, which are 1D chain structure featuring 6-member-water H-bonds cluster and 3D bbi-pillared wavy-like layer framework, respectively. As changing the metal ion to zinc ion, 3 exhibits 3D stp-pillared layer architecture, which discovers the effect of the central metal ions on themore » formation of metal–organic frameworks. The fluorescence studies show that the emissions of the coordination polymers are attributed to the ligand π–π* transition, which means they could be potential fluorescence materials. - Graphical abstract: Three new Cd{sup II}/Zn{sup II} 2-sulfoterephthalate (2-H{sub 3}stp) complexes with 1,4-bisbenzimidazole (1,4-bbi) are described. Complex 1 exhibits one-dimensional chain-like structure, 2 is a three-dimensional bbi-pillared wavy-like layer framework, while 3 is a three-dimensional stp-pillared layer architecture. Fluorescence spectra exhibit the π–π* transition of two organic ligands. - Highlights: • Three Cd{sup II}/Mn{sup II} 2-sulfoterephthalate complexes containing 1,4-bisbenzimidazole. • Different structural features despite the same raw materials for 1 and 2. • Fluorescence spectra exhibit the π–π* transition of organic ligands.« less

New 3D coordination polymers constructed from pillared metal-formate Kagomé layers exhibiting spin canting only in the nickel(II) complex.

PubMed

Li, Zuo-Xi; Zhao, Jiong-Peng; Sañudo, E C; Ma, Hong; Pan, Zhong-Da; Zeng, Yong-Fei; Bu, Xian-He

2009-12-21

Sparked by the strategy of pillared-layer MOFs, three formate coordination polymers, {[Ni(2)(HCO(2))(3)(L)(2)](NO(3)).2H(2)O}(infinity) (1), {[Co(2)(HCO(2))(3)(L)(2)](HCO(2)).2H(2)O}(infinity) (2), and {[Cu(2)(HCO(2))(3)(L)(2)](HCO(2)).2H(2)O}(infinity) (3), have been synthesized by employing the rodlike ligand 4,4'-bis(imidazol-1-yl)biphenyl (L) as the pillar. Structural analysis indicates that the title complexes 1-3 are isostructural compounds, which possess metal-formate 2D layers perpendicularly pillared by the ligand L to afford a 3D open framework. This is an interesting example of a Kagome lattice based on the formate mediator. Moreover, the formate anion of this 2D Kagome layer exhibits various bridging modes: anti-anti, syn-anti, and 3.21 modes. Their magnetic measurements reveals that only complex 1 presents the spin canting phenomenon, while its isostructural Co(II) and Cu(II) complexes are simply paramagnets with antiferromagnetic coupling.

Radiation-MHD models of elephant trunks and globules in HII regions

NASA Astrophysics Data System (ADS)

Mackey, Jonathan; Lim, Andrew J.

2011-01-01

We study the formation and evolution of pillars of dense gas, known as elephant trunks, at the boundaries of HII regions, formed by shadowing of ionising radiation by dense clumps. The effects of magnetic fields on this process are investigated using 3D radiation-magnetohydrodynamics simulations. For a simulation in which an initially uniform magnetic field of strength \\vert B\\vert≃50 μG is oriented perpendicular to the radiation propagation direction, the field is swept into alignment with the pillar during its dynamical evolution, in agreement with observations of the ``Pillars of Creation'' in M16, and of some cometary globules. This effect is significantly enhanced when the simulation is re-run with a weaker field of ≃18 μG. A stronger field with \\vert B\\vert≃ 160 μG is sufficient to prevent this evolution completely, also significantly affecting the photoionisation process. Using a larger simulation domain it is seen that the pillar formation models studied in Mackey & Lim (2010) ultimately evolve to cometary structures in the absence of dense gas further from the star.

Fabrication of hierarchically structured superhydrophobic PDMS surfaces by Cu and CuO casting

NASA Astrophysics Data System (ADS)

Migliaccio, Christopher P.; Lazarus, Nathan

2015-10-01

Poly(dimethylsiloxane) (PDMS) films decorated with hierarchically structured pillars are cast from large area copper and copper oxide negative molds. The molds are fabricated using a single patterning step and electroplating. The process of casting structured PDMS films is simpler and cheaper than alternatives based on deep reactive ion etching or laser roughening of bulk silicone. Texture imparted to the pillars from the mold walls renders the PDMS films superhydrophobic, with the contact angle/hysteresis of the most non-wetting surfaces measuring 164°/9° and 158°/10° for surfaces with and without application of a low surface energy coating. The usefulness of patterned PDMS films as a "self-cleaning" solar cell module covering is demonstrated and other applications are discussed.

A facile bacterial assisted electrochemical self-assembly of polypyrrole micro-pillars: towards underwater low adhesive superoleophobicity

NASA Astrophysics Data System (ADS)

Cheng, Zhe; Ding, Chunmei; Liu, Huan; Zhu, Ying; Jiang, Lei

2013-12-01

By taking advantage of bacterial extracellular electron transfer behavior, a facile method was developed to fabricate oriented polypyrrole micro-pillars (PPy-MP) with nanoscale surface roughness. Microbes acted as a living conductive template on which PPy was in situ polymerized. The as-prepared PPy-MP exhibit the distinctive underwater low adhesive superoleophobicity which is attributable to the unique hierarchical micro/nano-structures and the high surface energy by doping with inorganic small anions.By taking advantage of bacterial extracellular electron transfer behavior, a facile method was developed to fabricate oriented polypyrrole micro-pillars (PPy-MP) with nanoscale surface roughness. Microbes acted as a living conductive template on which PPy was in situ polymerized. The as-prepared PPy-MP exhibit the distinctive underwater low adhesive superoleophobicity which is attributable to the unique hierarchical micro/nano-structures and the high surface energy by doping with inorganic small anions. Electronic supplementary information (ESI) available: The shape of a water drop on PPy-MPA and cauliflower-like PPy film in air. See DOI: 10.1039/c3nr03788f

Proof-of-concept switchable hydrophobic/hydrophilic patterned surfaces from thermo-mechanically tailored acrylate systems

NASA Astrophysics Data System (ADS)

Laursen, Christopher M.

A novel, proof-of-concept, switchable hydrophobic/hydrophilic structured surface targeted to assist in antifouling of materials in aqueous environments was created through the development of a multi-tiered platform. The understructure consists of a thermo-mechanically tailored acrylate based polymer patterned in a pillared array, which was then overlaid with spatially tailored hydrophobic/hydrophilic surface chemistry treatments. Development focused on the synthesis of a ternary acrylate system displaying proper thermo-mechanical behavior in submerged conditions for the understructure, creation of a sufficient soft molding technique, and methods to chemically alter water-surface wetting interactions. The final acrylate based polymer constituents were chosen based on expected low-toxicity and the ability to be photopolymerized, while the final system displayed appropriate mechanical toughness, water absorption, and material stiffness over a select temperature window. This was important as alteration in wettability characteristics relied upon a stark transition in the polymeric materials stiffness within a narrow temperature range. The material qualitatively displayed a more hydrophobic state with the pillared surface structures erect, and a more hydrophilic state with the pillars bent over.

Spatiotemporal deep imaging of syncytium induced by the soybean cyst nematode Heterodera glycines.

PubMed

Ohtsu, Mina; Sato, Yoshikatsu; Kurihara, Daisuke; Suzaki, Takuya; Kawaguchi, Masayoshi; Maruyama, Daisuke; Higashiyama, Tetsuya

2017-11-01

Parasite infections cause dramatic anatomical and ultrastructural changes in host plants. Cyst nematodes are parasites that invade host roots and induce a specific feeding structure called a syncytium. A syncytium is a large multinucleate cell formed by cell wall dissolution-mediated cell fusion. The soybean cyst nematode (SCN), Heterodera glycines, is a major soybean pathogen. To investigate SCN infection and the syncytium structure, we established an in planta deep imaging system using a clearing solution ClearSee and two-photon excitation microscopy (2PEM). Using this system, we found that several cells were incorporated into the syncytium; the nuclei increased in size and the cell wall openings began to be visible at 2 days after inoculation (DAI). Moreover, at 14 DAI, in the syncytium developed in the cortex, there were thickened concave cell wall pillars that resembled "Parthenon pillars." In contrast, there were many thick board-like cell walls and rarely Parthenon pillars in the syncytium developed in the stele. We revealed that the syncytia were classified into two types based on the pattern of the cell wall structures, which appeared to be determined by the position of the syncytium inside roots. Our results provide new insights into the developmental process of syncytium induced by cyst nematode and a better understanding of the three-dimensional structure of the syncytium in host roots.

Determination of concrete cover thickness in a reinforced concrete pillar by observation of the scattered electromagnetic field

NASA Astrophysics Data System (ADS)

Di Gregorio, Pietro Paolo; Frezza, Fabrizio; Mangini, Fabio; Pajewski, Lara

2017-04-01

The electromagnetic scattered field by a reinforced concrete structure is calculated by means of frequency-domain numerical simulations and by making use of the scattered-field formulation. The concrete pillar, used as supporting architectural element, is modelled as a parallelepiped shell made of concrete material inside which are present steel bars. In order to make the model simpler, the steel bars are supposed running parallel to the air-pillar interface. To excite the model, a linearly-polarized plane wave impinging normally with respect to the pillars surface, is adopted. We consider two different polarizations in order to determine the most useful in terms of scattered-field sensitivity. Moreover, a preliminary frequency sweep allows us to choose the most suitable operating frequency depending on the dimensions of the pillar cross-section, the steel bars cross-section and the concrete cover. All the three components of the scattered field are monitored along a line just above the interface air-pillar. The electromagnetic properties of the materials employed in this study are present in the literature and, since a frequency-domain technique is adopted, no further approximation is needed. The results obtained for different values of the concrete cover are compared, with the goal of determining the scattered field dependence on the concrete cover thickness. Considering different concrete cover thicknesses, we want to provide an electromagnetic method to obtain this useful parameter by observation of the scattered electromagnetic field. One of the practical applications of this study in the field of Civil Engineering may be the use of ground penetrating radar (GPR) techniques to monitor the thickness of the concrete that separates the metal bars embedded in the pillar from the outer surface. A correct distance is useful because the concrete cover serves as a protection against external agents avoiding corrosion of the bars that might prejudice the reinforced concrete; it ensures also an optimal transmission and distribution of the adhesion forces in the pillar. Acknowledgement This work is a contribution to COST Action TU1208 "Civil Engineering Applications of Ground Penetrating Radar" (www.GPRadar.eu, www.cost.eu).

Resonant characteristics and sensitivity dependency on the contact surface in QCM-micropillar-based system of coupled resonator sensors

NASA Astrophysics Data System (ADS)

Kashan, M. A. M.; Kalavally, V.; Lee, H. W.; Ramakrishnan, N.

2016-05-01

We report the characteristics and sensitivity dependence over the contact surface in coupled resonating sensors (CRSs) made of high aspect ratio resonant micropillars attached to a quartz crystal microbalance (QCM). Through experiments and simulation, we observed that when the pillars of resonant heights were placed in maximum displacement regions the resonance frequency of the QCM increased following the coupled resonance characteristics, as the pillar offered elastic loading to the QCM surface. However, the same pillars when placed in relatively lower displacement regions, in spite of their resonant dimension, offered inertial loading and resulted in a decrease in QCM resonance frequency, as the displacement amplitude was insufficient to couple the vibrations from the QCM to the pillars. Accordingly, we discovered that the coupled resonance characteristics not only depend on the resonant structure dimensions but also on the contact regions in the acoustic device. Further analysis revealed that acoustic pressure at the contact surface also influences the resonance frequency characteristics and sensitivity of the CRS. To demonstrate the significance of the present finding for sensing applications, humidity sensing is considered as the example measurand. When a sensing medium made of resonant SU-8 pillars was placed in a maximum displacement region on a QCM surface, the sensitivity increased by 14 times in comparison to a resonant sensing medium placed in a lower displacement region of a QCM surface.

The role of education in the culture of four pillar poverty to establish the nationalism of young generation

NASA Astrophysics Data System (ADS)

Sarmini; Warsono

2018-01-01

Globalization as an international integration process brings several positive and negative impacts due to the exchange of world views, products, thoughts, and other cultural aspects that can diminish the values of national identity. Four pillars of nationality are needed as a foundation to counteract the negative effects of globalization, therefore a culturally, educative, legal and structural approach is needed so that the younger generation can truly understand and safeguard the four pillars of our nationality. So far the government has also played little role in building the four pillars into an education. This research intends to see how the role of education can build young generation of nationalism by using research design in the form of content analysis. The population in this study is the Education Office of Sidoarjo Regency, which is the level of Junior High School Education Unit. However, given the scope and breadth of the district of Sidoarjo, a representative sample is determined using FGD (Focus Group Discussion) data collection techniques and questionnaires that will be analyzed using written policy descriptions or unwritten policies. Through a series of research stages, it can be concluded that there are still many principals who have not integrated the culture of the four pillars of nationalism into a written and unwritten document covering intracurricular, extracurricular, school culture and through community participation.

Electrolytic Manganese Dioxide Coatings on High Aspect Ratio Micro-Pillar Arrays for 3D Thin Film Lithium Ion Batteries.

PubMed

Zargouni, Yafa; Deheryan, Stella; Radisic, Alex; Alouani, Khaled; Vereecken, Philippe M

2017-05-27

In this work, we present the electrochemical deposition of manganese dioxide (MnO₂) thin films on carbon-coated TiN/Si micro-pillars. The carbon buffer layer, grown by plasma enhanced chemical vapor deposition (PECVD), is used as a protective coating for the underlying TiN current collector from oxidation, during the film deposition, while improving the electrical conductivity of the stack. A conformal electrolytic MnO₂ (EMD) coating is successfully achieved on high aspect ratio C/TiN/Si pillar arrays by tailoring the deposition process. Lithiation/Delithiation cycling tests have been performed. Reversible insertion and extraction of Li⁺ through EMD structure are observed. The fabricated stack is thus considered as a good candidate not only for 3D micorbatteries but also for other energy storage applications.

Electrolytic Manganese Dioxide Coatings on High Aspect Ratio Micro-Pillar Arrays for 3D Thin Film Lithium Ion Batteries

PubMed Central

Zargouni, Yafa; Deheryan, Stella; Radisic, Alex; Alouani, Khaled; Vereecken, Philippe M.

2017-01-01

In this work, we present the electrochemical deposition of manganese dioxide (MnO2) thin films on carbon-coated TiN/Si micro-pillars. The carbon buffer layer, grown by plasma enhanced chemical vapor deposition (PECVD), is used as a protective coating for the underlying TiN current collector from oxidation, during the film deposition, while improving the electrical conductivity of the stack. A conformal electrolytic MnO2 (EMD) coating is successfully achieved on high aspect ratio C/TiN/Si pillar arrays by tailoring the deposition process. Lithiation/Delithiation cycling tests have been performed. Reversible insertion and extraction of Li+ through EMD structure are observed. The fabricated stack is thus considered as a good candidate not only for 3D micorbatteries but also for other energy storage applications. PMID:28555017

Photonic Waveguide Choke Joint with Non-Absorptive Loading

NASA Technical Reports Server (NTRS)

Wollack, Edward J. (Inventor); U-Yen, Kongpop (Inventor); Chuss, David T. (Inventor)

2016-01-01

A waveguide choke joint includes a first array of pillars positioned on a substrate, each pillar in the first array of pillars having a first size and configured to receive an input plane wave at a first end of the choke joint. The choke joint has a second end configured to transmit the input plane wave away from the choke joint. The choke joint further includes a second array of pillars positioned on the substrate between the first array of pillars and the second end of the choke joint. Each pillar in the second array of pillars has a second size. The choke joint also has a third array of pillars positioned on the substrate between the second array and the second end of the choke joint. Each pillar in the third array of pillars has a third size.

Use of Structure-from-Motion Photogrammetry Technique to model Danxia red bed landform slope stability by discrete element modeling - case study at Mt. Langshan, Hunan Province, China

NASA Astrophysics Data System (ADS)

Simonson, Scott; Hua, Peng; Luobin, Yan; Zhi, Chen

2016-04-01

Important to the evolution of Danxia landforms is how the rock cliffs are in large part shaped by rock collapse events, ranging from small break offs to large collapses. Quantitative research of Danxia landform evolution is still relatively young. In 2013-2014, Chinese and Slovak researchers conducted joint research to measure deformation of two large rock walls. In situ measurements of one rock wall found it to be stable, and Ps-InSAR measurements of the other were too few to be validated. Research conducted this year by Chinese researchers modeled the stress states of a stone pillar at Mt. Langshan, in Hunan Province, that toppled over in 2009. The model was able to demonstrate how stress states within the pillar changed as the soft basal layer retreated, but was not able to show the stress states at the point of complete collapse. According to field observations, the back side of the pillar fell away from the entire cliff mass before the complete collapse, and no models have been able to demonstrate the mechanisms behind this behavior. A further understanding of the mechanisms controlling rockfall events in Danxia landforms is extremely important because these stunning sceneries draw millions of tourists each year. Protecting the tourists and the infrastructure constructed to accommodate tourism is of utmost concern. This research will employ a UAV to as universally as possible photograph a stone pillar at Mt. Langshan that stands next to where the stone pillar collapsed in 2009. Using the recently developed structure-from-motion technique, a 3D model of the pillar will be constructed in order to extract geometrical data of the entire slope and its structural fabric. Also in situ measurements will be taken of the slope's toe during the field work exercises. These data are essential to constructing a realistic discrete element model using the 3DEC code and perform a kinematic analysis of the rock mass. Intact rock behavior will be based on the Mohr Coulomb Plasticity Model. Physical and mechanical parameters of the continuum and discontinuum elements will be gathered from laboratory experiments and used as constitutive criteria parameters within the 3DEC model. This research hopes to show how easily and relatively cheaply previously unaccessible Danxia landform geometrical data can be obtained using readily available photographic and software technologies. Also, obtaining a clearer quantitative understanding of the mechanisms controlling slope failure in Danxia landscapes will help future land planners appropriately take advantage of these outstanding scenic sites.

Evaluating bump control techniques through convergence monitoring

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

Campoli, A.A.

1987-07-01

A coal mine bump is the violent failure of a pillar or pillars due to overstress. Retreat coal mining concentrates stresses on the pillars directly outby gob areas, and the situation becomes critical when mining a coalbed encased in rigid associated strata. Bump control techniques employed by the Olga Mine, McDowell County, WV, were evaluated through convergence monitoring in a Bureau of Mines study. Olga uses a novel pillar splitting mining method to extract 55-ft by 70-ft chain pillars, under 1,100 to 1,550 ft of overburden. Three rows of pillars are mined simultaneously to soften the pillar line and reducemore » strain energy storage capacity. Localized stress reduction (destressing) techniques, auger drilling and shot firing, induced approximately 0.1 in. of roof-to-floor convergence in ''high'' -stress pillars near the gob line. Auger drilling of a ''low''-stress pillar located between two barrier pillars produced no convergence effects.« less

Pessimistic Determination of Mechanical Conditions and Micro/macroeconomic Evaluation of Mine Pillar Replacement

NASA Astrophysics Data System (ADS)

Chen, Qingfa; Zhao, Fuyu

2017-12-01

Numerous pillars are left after mining of underground mineral resources using the open stope method or after the first step of the partial filling method. The mineral recovery rate can, however, be improved by replacement recovery of pillars. In the present study, the relationships among the pillar type, minimum pillar width, and micro/macroeconomic factors were investigated from two perspectives, namely mechanical stability and micro/macroeconomic benefit. Based on the mechanical stability formulas for ore and artificial pillars, the minimum width for a specific pillar type was determined using a pessimistic criterion. The microeconomic benefit c of setting an ore pillar, the microeconomic benefit w of artificial pillar replacement, and the economic net present value (ENPV) of the replacement process were calculated. The values of c and w were compared with respect to ENPV, based on which the appropriate pillar type and economical benefit were determined.

Pillared Graphene: A New 3-D Innovative Network Nanostructure Augments Hydrogen Storage

NASA Astrophysics Data System (ADS)

Georgios, Dimitrakakis K.; Emmanuel, Tylianakis; George, Froudakis E.

2009-08-01

Nowadays, people have turned into finding an alternative power source for everyday applications. One of the most promising energy fuels is hydrogen. It can be used as an energy carrier at small portable devices (e.g. laptops and/or cell phones) up to larger, like cars. Hydrogen is considered as the perfect fuel. It can be burnt in combustion engines and the only by-product is water. For hydrogen-powered vehicles a big liming factor is the gas tank and is the reason for not using widely hydrogen in automobile applications. According to United States' Department of Energy (D.O.E.) the target for reversible hydrogen storage in mobile applications is 6% wt. and 45 gr. H2/L and these should be met by 2010. After their synthesis Carbon Nanotubes (CNTs) were considered as ideal candidates for hydrogen storage especially after some initially incorrect but invitingly results. As it was proven later, pristine carbon nanotubes cannot achieve D.O.E.'s targets in ambient conditions of pressure and temperature. Therefore, a way to increase their hydrogen storage capacity should be found. An attempt was done by doping CNTs with alkali metal atoms. Although the results were promising, even that increment was not enough. Consequently, new architectures were suggested as materials that could potentially enhance hydrogen storage. In this work a novel three dimensional (3-D) nanoporous carbon structure called Pillared Graphene (Figure 1) is proposed for augmented hydrogen storage in ambient conditions. Pillared Graphene consists of parallel graphene sheets and CNTs that act like pillars and support the graphene sheets. The entire structure (Figure 1) can be resembled like a building in its early stages of construction, where the floors are represented by graphene sheets and the pillars are the CNTs. As shown in Figure 1, CNTs do not penetrate the structure from top to bottom. Instead, they alternately go up and down, so that on the same plane do not exist two neighboring CNTs with the same orientation. In addition, the structure has no expanding limits and this is shown by the unfinished CNTs on the top and bottom of the structure (Figure 1). Obviously, the length and the intertube distance of the CNTs can be changed at will in order to have a material with tunable pores. This tailored porosity is a key aspect of our material and thus its usage can be extended to other applications besides hydrogen storage. The stability of the structure was determined by DFT calculations using the Turbomole ab-initio package. As it was shown by these calculations, our material is stable and in principle it can be formed. Its hydrogen storage capacity was then evaluated by Grand Canonical Monte Carlo (GCMC) calculations and the results showed a spectacular increase when Pillared Graphene was doped with lithium atoms. The increment on the loading when lithium atoms were present was so high that our material was able to store 6.1% wt. and 41 gr./L of hydrogen under ambient conditions.

The possibility of increasing the efficiency of accessible coal deposits by optimizing dimensions of protective pillars or the scope of exploitation

NASA Astrophysics Data System (ADS)

Bańka, Piotr; Badura, Henryk; Wesołowski, Marek

2017-11-01

One of the ways to protect objects exposed to the influences of mining exploitation is establishing protective pillars for them. Properly determined pillar provides effective protection of the object for which it was established. Determining correct dimensions of a pillar requires taking into account contradictory requirements. Protection measures against the excessive influences of mining exploitation require designing the largest possible pillars, whereas economic requirements suggest a maximum reduction of the size of resources left in the pillar. This paper presents algorithms and programs developed for determining optimal dimensions of protective pillars for surface objects and shafts. The issue of designing a protective pillar was treated as a nonlinear programming task. The objective function are the resources left in a pillar while nonlinear limitations are the deformation values evoked by the mining exploitation. Resources in the pillar may be weighted e.g. by calorific value or by the inverse of output costs. The possibility of designing pillars of any polygon shape was taken into account. Because of the applied exploitation technologies the rectangular pillar shape should be considered more advantageous than the oval one, though it does not ensure the minimization of resources left in a pillar. In this article there is also presented a different approach to the design of protective pillars, which instead of fixing the pillar boundaries in subsequent seams, the length of longwall panels of the designed mining exploitation is limited in a way that ensures the effective protection of an object while maximizing the extraction ratio of the deposit.

Evaluating 8 pillars of Total Productive Maintenance (TPM) implementation and their contribution to manufacturing performance

NASA Astrophysics Data System (ADS)

Adesta, E. Y. T.; Prabowo, H. A.; Agusman, D.

2018-01-01

TPM is one method to improve manufacturing performance through an emphasis on maintenance that involves everyone in the organization. Research on the application of TPM and its relevance to the manufacturing performance has been performed quite a lot. However, to the best of our knowledge, a study that deliberates how the application of 8 pillars TPM (especially in developing countries) is still hard to find. This paper attempts to evaluate in more detail about how the 8 pillars of TPM are applied in Indonesia and their impact on manufacturing performance. This research is a pilot study with a target of 50 companies. From the results of data collection, only 22 companies (44%) are eligible to process. Data processing was performed using SPSS and Smart PLS tools. From the validity and reliability tests, it can be seen that all items/indicators for TPM pillars are valid and reliable with correlation value (R) of 0.614 - 0.914 and with Cronbach’s alpha equal to 0.753. As for the Manufacturing Performance construct, the Delivery indicator was not valid. In overall, the model is reliable with Cronbach’s alpha of 0.710. From the results of Confirmatory Factors Analysis (CFA) for TPM, it can be seen that four indicators (pillars) are highly significant while four other indicators are less significant. For MP, three indicators are significant, and two are not significant. In general, the structural model of the relationship between TPM and MP is relatively strong and positive with values R = 0.791, and R squared = 0.626. This means that the TPM Pillars can explain 62.6% MP variability construct variable, while the other 37.4% can be explained by unrelated variables.

Mesoporous Phosphate Heterostructures: Synthesis and Application on Adsorption and Catalysis

NASA Astrophysics Data System (ADS)

Moreno-Tost, Ramón; Jiménez-Jiménez, José; Infantes-Molina, Antonia; Cavalcante, Celio L.; Azevedo, Diana C. S.; Soriano, María Dolores; López Nieto, José Manuel; Jiménez-López, Antonio; Rodríguez-Castellón, Enrique

Porous phosphate heterostructures (PPHs) are solids formed by a layered metal(IV) phosphate expanded with silica galleries obtained by combining the two main strategies for obtaining mesoporous materials [pillared layered structures (PLS') and MCM-41]. The different synthetic pathways for obtaining mesoporous phosphate structures with silica galleries with Zr- or Ti-doped silica, the study of their structural, textural and acid properties, its functionalisation with different organic substances such as propionitrile, 3-aminopropyl triethoxysilane, (3-mercaptopropyl)trimethoxysilane, vinyltrimethoxysilane, phenyltriethoxysilane and 3-(triethoxysilyl)propionitrile are discussed. The preparation of metal-supported catalysts and their application in gas separation, adsorption and catalysis are reviewed. Specifically, the use of Cu- and Fe-exchanged PPH for the adsorption of benzothiophene and the separation of propane/propene is the main application as adsorbent. The hydrotreating of aromatic hydrocarbons using ruthenium-impregnated catalysts via hydrogenation and hydrogenolysis/hydrocracking for the production of clean diesel fuels, the selective catalytic reduction of NO from stationary and mobile sources by using Cu-PPH with 1, 3 and 7 wt% of Cu and the selective oxidation of hydrogen sulphide to sulphur with vanadium-containing PPH are the three catalytic reactions of environmental interest studied.

Wetting transition on patterned surfaces: transition states and energy barriers.

PubMed

Ren, Weiqing

2014-03-18

We study the wetting transition on microstructured hydrophobic surfaces. We use the string method [J. Chem. Phys. 2007, 126, 164103; J. Chem. Phys. 2013, 138, 134105] to accurately compute the transition states, the energy barriers, and the minimum energy paths for the wetting transition from the Cassie-Baxter state to the Wenzel state. Numerical results are obtained for the wetting of a hydrophobic surface textured with a square lattice of pillars. It is found that the wetting of the solid substrate occurs via infiltration of the liquid in a single groove, followed by lateral propagation of the liquid front. The propagation of the liquid front proceeds in a stepwise manner, and a zipping mechanism is observed during the infiltration of each layer. The minimum energy path for the wetting transition goes through a sequence of intermediate metastable states, whose wetted areas reflect the microstructure of the patterned surface. We also study the dependence of the energy barrier on the drop size and the gap between the pillars.

Pillars of Creation among Destruction: Star Formation in Molecular Clouds near R136 in 30 Doradus

NASA Astrophysics Data System (ADS)

Kalari, Venu M.; Rubio, Mónica; Elmegreen, Bruce G.; Guzmán, Viviana V.; Zinnecker, Hans; Herrera, Cinthya N.

2018-01-01

We present new sensitive CO(2–1) observations of the 30 Doradus region in the Large Magellanic Cloud. We identify a chain of three newly discovered molecular clouds that we name KN1, KN2, and KN3 lying within 2–14 pc in projection from the young massive cluster R136 in 30 Doradus. Excited H2 2.12 μm emission is spatially coincident with the molecular clouds, but ionized Brγ emission is not. We interpret these observations as the tails of pillar-like structures whose ionized heads are pointing toward R136. Based on infrared photometry, we identify a new generation of stars forming within this structure.

Durable and mass producible polymer surface structures with different combinations of micro-micro hierarchy

NASA Astrophysics Data System (ADS)

Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A.

2016-01-01

Extensive studies have been performed with the aim of fabricating hierarchical surface structures inspired by nature. However, synthetic hierarchical structures have to sacrifice mechanical resistance to functionality by introducing finer scaled structures. Therefore, surfaces are less durable. Surface micro-micro hierarchy has been proven to be effective in replacing micro-nano hierarchy in the sense of superhydrophobicity. However, less attention has been paid to the combined micro-micro hierarchies with surface pillars and pits incorporated together. The fabrication of this type of hierarchy may be less straightforward, with the possibility of being a complicated multi-step process. In this study, we present a simple yet mass producible fabrication method for hierarchical structures with different combinations of surface pillars and pits. The fabrication was based on only one aluminum (Al) mold with sequential mountings. The fabricated structures exhibit high mechanical durability and structural stabilities with a normal load up to 100 kg. In addition, the theoretical estimation of the wetting state shows a promising way of stabilizing a water droplet on the surface pit structures with a more stable Cassie-Baxter state.

Replication of surface nano-structure of the wing of dragonfly ( Pantala Flavescens) using nano-molding and UV nanoimprint lithography

NASA Astrophysics Data System (ADS)

Cho, Joong-Yeon; Kim, Gyutae; Kim, Sungwook; Lee, Heon

2013-07-01

The hydrophobicity of a dragonfly's wing originates from the naturally occurring nano-structure on its surface. The nano-structure on a dragonfly's wing consists of an array of nano-sized pillars, 100 nm in diameter. We re-create this hydrophobicity on various substrates, such as Si, glass, curved acrylic polymer, and flexible PET film, by replicating the nano-structure using UV curable nano-imprint lithography (NIL) and PDMS molding. The success of the nano-structure duplication was confirmed using scanning electron microscopy (SEM). The hydrophobicity was measured by water-based contact angle measurements. The water contact angle of the replica made of UV cured polymer was 135° ± 2°, which was slightly lower than that of the original dragonfly's wing (145° ± 2°), but much higher than that of the UV cured polymer surface without any nano-sized pillars (80°). The hydrophobicity was further improved by applying a coating of Teflon-like material.

Enhancing elastic stress relaxation in SiGe/Si heterostructures by Si pillar necking

NASA Astrophysics Data System (ADS)

Isa, F.; Salvalaglio, M.; Arroyo Rojas Dasilva, Y.; Jung, A.; Isella, G.; Erni, R.; Timotijevic, B.; Niedermann, P.; Gröning, P.; Montalenti, F.; von Känel, H.

2016-10-01

We demonstrate that the elastic stress relaxation mechanism in micrometre-sized, highly mismatched heterostructures may be enhanced by employing patterned substrates in the form of necked pillars, resulting in a significant reduction of the dislocation density. Compositionally graded Si1-xGex crystals were grown by low energy plasma enhanced chemical vapour deposition, resulting in tens of micrometres tall, three-dimensional heterostructures. The patterned Si(001) substrates consist of micrometre-sized Si pillars either with the vertical {110} or isotropically under-etched sidewalls resulting in narrow necks. The structural properties of these heterostructures were investigated by defect etching and transmission electron microscopy. We show that the dislocation density, and hence the competition between elastic and plastic stress relaxation, is highly influenced by the shape of the substrate necks and their proximity to the mismatched epitaxial material. The SiGe dislocation density increases monotonically with the crystal width but is significantly reduced by the substrate under-etching. The drop in dislocation density is interpreted as a direct effect of the enhanced compliance of the under-etched Si pillars, as confirmed by the three-dimensional finite element method simulations of the elastic energy distribution.

Field Investigation of a Roof Fall Accident and Large Roadway Deformation Under Geologically Complex Conditions in an Underground Coal Mine

NASA Astrophysics Data System (ADS)

Wang, Hongwei; Xue, Sheng; Jiang, Yaodong; Deng, Daixin; Shi, Suzhen; Zhang, Dengqiang

2018-06-01

An investigation was undertaken to study the characteristics of large roadway deformation and driving force of roof fall in a geologically complex zone at Huangyanhui underground coal mine, Shanxi Province, China, and to determine the main factors contributing to a roof fall accident that occurred in this mine. A series of field tests were conducted in the mine to study the geological structures, in situ stress, excavation-damaged zones of the roadway, roof-to-floor and sidewall convergences, roof separation, bolts loading and island coal pillar stress. The results of these tests have revealed that the driving force of the large roadway deformation and roof fall was not the activation of the karst collapsed pillars or concentration stress in island coal pillar, but high levels of horizontal tectonic stress and fault slip were induced by mining activities.

Hetero-junction photovoltaic device and method of fabricating the device

DOEpatents

Aytug, Tolga; Christen, David K; Paranthaman, Mariappan Parans; Polat, Ozgur

2014-02-10

A hetero-junction device and fabrication method in which phase-separated n-type and p-type semiconductor pillars define vertically-oriented p-n junctions extending above a substrate. Semiconductor materials are selected for the p-type and n-type pillars that are thermodynamically stable and substantially insoluble in one another. An epitaxial deposition process is employed to form the pillars on a nucleation layer and the mutual insolubility drives phase separation of the materials. During the epitaxial deposition process, the orientation is such that the nucleation layer initiates propagation of vertical columns resulting in a substantially ordered, three-dimensional structure throughout the deposited material. An oxidation state of at least a portion of one of the p-type or the n-type semiconductor materials is altered relative to the other, such that the band-gap energy of the semiconductor materials differ with respect to stoichiometric compositions and the device preferentially absorbs particular selected bands of radiation.

Supra-Nanoparticle Functional Assemblies through Programmable Stacking.

PubMed

Tian, Cheng; Cordeiro, Marco Aurelio L; Lhermitte, Julien; Xin, Huolin L; Shani, Lior; Liu, Mingzhao; Ma, Chunli; Yeshurun, Yosef; DiMarzio, Donald; Gang, Oleg

2017-07-25

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. Here, we report a general method of assembling nanoparticles in a linear "pillar" morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization. By controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.

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

Wong-Ng, Winnie; Culp, Jeffrey T.; Chen, Yu-S.

The chartreuse monoclinic Ni-dpbz (Ni(L)[Ni(CN) 4], (L = 1,4-Bis(4-pyridyl)benzene, or dpbz) crystal assumes a pillared structure with layers defined by 2-D Ni[Ni(CN) 4] n nets and dpbz ligands as pillars, linking between coordinated Ni sites. In addition to the hysteretic adsorption/desorption feature of Ni-dpbz, in half of the parallelepiped-shape space enclosed by the pillars and nets, an additional dpbz ligand was found to link between the open ends of two four-fold Ni sites. This arrangement results in an unusual 5-fold pseudo square-pyramid environment for Ni and a significantly long Ni–N distance of 2.369(4) Å. The presence of disordered dimethyl sulfoxidemore » (DMSO) solvent molecules give rise to the formula of Ni(dpbz)[Ni(CN) 4]·½dpbz·0.44DMSO. Sorption isotherms showed flexible behavior during the adsorption and desorption of CO 2.« less

Lateral spin transfer torque induced magnetic switching at room temperature demonstrated by x-ray microscopy

NASA Astrophysics Data System (ADS)

Buhl, M.; Erbe, A.; Grebing, J.; Wintz, S.; Raabe, J.; Fassbender, J.

2013-10-01

Changing and detecting the orientation of nanomagnetic structures, which can be used for durable information storage, needs to be developed towards true nanoscale dimensions for keeping up the miniaturization speed of modern nanoelectronic components. Therefore, new concepts for controlling the state of nanomagnets are currently in the focus of research in the field of nanoelectronics. Here, we demonstrate reproducible switching of a purely metallic nanopillar placed on a lead that conducts a spin-polarized current at room temperature. Spin diffusion across the metal-metal (Cu to CoFe) interface between the pillar and the lead causes spin accumulation in the pillar, which may then be used to set the magnetic orientation of the pillar. In our experiments, the detection of the magnetic state of the nanopillar is performed by direct imaging via scanning transmission x-ray microscopy (STXM).

Thyroid hormone increases fibroblast growth factor receptor expression and disrupts cell mechanics in the developing organ of corti

PubMed Central

2013-01-01

Background Thyroid hormones regulate growth and development. However, the molecular mechanisms by which thyroid hormone regulates cell structural development are not fully understood. The mammalian cochlea is an intriguing system to examine these mechanisms, as cellular structure plays a key role in tissue development, and thyroid hormone is required for the maturation of the cochlea in the first postnatal week. Results In hypothyroid conditions, we found disruptions in sensory outer hair cell morphology and fewer microtubules in non-sensory supporting pillar cells. To test the functional consequences of these cytoskeletal defects on cell mechanics, we combined atomic force microscopy with live cell imaging. Hypothyroidism stiffened outer hair cells and supporting pillar cells, but pillar cells ultimately showed reduced cell stiffness, in part from a lack of microtubules. Analyses of changes in transcription and protein phosphorylation suggest that hypothyroidism prolonged expression of fibroblast growth factor receptors, and decreased phosphorylated Cofilin. Conclusions These findings demonstrate that thyroid hormones may be involved in coordinating the processes that regulate cytoskeletal dynamics and suggest that manipulating thyroid hormone sensitivity might provide insight into the relationship between cytoskeletal formation and developing cell mechanical properties. PMID:23394545

Pretest parametric calculations for the heated pillar experiment in the WIPP In-Situ Experimental Area

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

Branstetter, L.J.

Results are presented for a pretest parametric study of several configurations and heat loads for the heated pillar experiment (Room H) in the Waste Isolation Pilot Plant (WIPP) In Situ Experimental Area. The purpose of this study is to serve as a basis for selection of a final experiment geometry and heat load. The experiment consists of a pillar of undisturbed rock salt surrounded by an excavated annular room. The pillar surface is covered by a blanket heat source which is externally insulated. A total of five thermal and ten structural calculations are described in a four to five yearmore » experimental time frame. Results are presented which include relevant temperature-time histories, deformations, rock salt stress component and effective stress profiles, and maximum stresses in anhydrite layers which are in close proximity to the room. Also included are predicted contours of a conservative post-processed measure of potential salt failure. Observed displacement histories are seen to be highly dependent on pillar and room height, but insensitive to other geometrical variations. The use of a tensile cutoff across slidelines is seen to produce more accurate predictions of anhydrite maximum stress, but to have little effect on rock salt stresses. The potential for salt failure is seen to be small in each case for the time frame of interest, and is only seen at longer times in the center of the room floor.« less

The pathway to intelligent implants: osteoblast response to nano silicon-doped hydroxyapatite patterning

PubMed Central

Munir, G.; Koller, G.; Di Silvio, L.; Edirisinghe, M. J.; Bonfield, W.; Huang, J.

2011-01-01

Bioactive hydroxyapatite (HA) with addition of silicon (Si) in the crystal structure (silicon-doped hydroxyapatite (SiHA)) has become a highly attractive alternative to conventional HA in bone replacement owing to the significant improvement in the in vivo bioactivity and osteoconductivity. Nanometre-scaled SiHA (nanoSiHA), which closely resembles the size of bone mineral, has been synthesized in this study. Thus, the silicon addition provides an extra chemical cue to stimulate and enhance bone formation for new generation coatings, and the next stage in metallic implantation design is to further improve cellular adhesion and proliferation by control of cell alignment. Topography has been found to provide a powerful set of signals for cells and form contact guidance. Using the recently developed novel technique of template-assisted electrohydrodynamic atomization (TAEA), patterns of pillars and tracks of various dimensions of nanoSiHA were achieved. Modifying the parameters of TAEA, the resolution of pattern structures was controlled, enabling the topography of a substrate to be modified accordingly. Spray time, flow rate and distance between the needle and substrate were varied to improve the pattern formation of pillars and tracks. The 15 min deposition time provided the most consistent patterned topography with a distance of 50 mm and flow rate of 4 µl min−1. A titanium substrate was patterned with pillars and tracks of varying widths, line lengths and distances under the optimized TAEA processing condition. A fast bone-like apatite formation rate was found on nanoSiHA after immersion in simulated body fluid, thus demonstrating its high in vitro bioactivity. Primary human osteoblast (HOB) cells responded to SiHA patterns by stretching of the filopodia between track and pillar, attaching to the apex of the pillar pattern and stretching between two. HOB cells responded to the track pattern by elongating along and between the track, and the length of HOB cells was proportional to the gaps between track patterns, but this relationship was not observed on the pillar patterns. The study has therefore provided an insight for future design of next generation implant surfaces to control and guide cellular responses, while TAEA patterning provides a controllable technique to provide topography to medical implants. PMID:21208969

Optimization research of structural parameters in non-pillar sublevel caving method with large structural parameters

NASA Astrophysics Data System (ADS)

Han, Wencheng; Zhou, Renjie; Liu, Xianfeng; Sun, Dongdong

2018-03-01

The non-pillar sublevel caving method with large structural parameters used in Mao Gong Iron Mine is of high rate of dilution and loss, and the ore recovery rate is less than 50%. Aiming at this problem, this paper analyzes the influence mechanism of the caving step on the mining index by means of the matching relationship between the shape of caved ore body and the drawn-out ore body, then through the physical simulation experiment in laboratory, the mining index such as the volume of pure ore drawing, ore recovery ratio and rock mixing ratio are studied under different caving step. The results show that the mining index under caving step of two row of blast hole is better than that under caving step of one row of blast hole. The research has guided significance for production of the mine.

Attempted caveolae-mediated phagocytosis of surface-fixed micro-pillars by human osteoblasts.

PubMed

Moerke, Caroline; Mueller, Petra; Nebe, Barbara

2016-01-01

Cells are sensitive to their underlying micro- and nano-topography, but the complex interplay is not completely understood especially if sharp edges and ridges of stochastically modified surfaces interfere with an attached cell body. Micro-topography offers cues that evoke a large range of cell responses e.g. altered adhesion behavior and integrin expression resulting in disturbed cell functions. In this study, we analyzed why osteoblastic cells mimic the underlying geometrical micro-pillar structure (5 × 5 × 5 μm, spacing of 5 μm) with their actin cytoskeleton. Interestingly, we discovered an attempted caveolae-mediated phagocytosis of each micro-pillar beneath the cells, which was accompanied by increased intracellular reactive oxygen species (ROS) production and reduced intracellular ATP levels. This energy consuming process hampered the cells in their function as osteoblasts at the interface. The raft-dependent/caveolae-mediated phagocytic pathway is regulated by diverse cellular components including caveolin-1 (Cav-1), cholesterol, actin cytoskeleton as well as actin-binding proteins like annexin A2 (AnxA2). Our results show a new aspect of osteoblast-material interaction and give insight into how cells behave on extraordinary micro-structures. We conclude that stochastically structured implants used in orthopedic surgery should avoid any topographical heights which induce phagocytosis to prevent their successful ingrowth. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Deformation-driven diffusion and plastic flow in amorphous granular pillars.

PubMed

Li, Wenbin; Rieser, Jennifer M; Liu, Andrea J; Durian, Douglas J; Li, Ju

2015-06-01

We report a combined experimental and simulation study of deformation-induced diffusion in compacted quasi-two-dimensional amorphous granular pillars, in which thermal fluctuations play a negligible role. The pillars, consisting of bidisperse cylindrical acetal plastic particles standing upright on a substrate, are deformed uniaxially and quasistatically by a rigid bar moving at a constant speed. The plastic flow and particle rearrangements in the pillars are characterized by computing the best-fit affine transformation strain and nonaffine displacement associated with each particle between two stages of deformation. The nonaffine displacement exhibits exponential crossover from ballistic to diffusive behavior with respect to the cumulative deviatoric strain, indicating that in athermal granular packings, the cumulative deviatoric strain plays the role of time in thermal systems and drives effective particle diffusion. We further study the size-dependent deformation of the granular pillars by simulation, and find that different-sized pillars follow self-similar shape evolution during deformation. In addition, the yield stress of the pillars increases linearly with pillar size. Formation of transient shear lines in the pillars during deformation becomes more evident as pillar size increases. The width of these elementary shear bands is about twice the diameter of a particle, and does not vary with pillar size.

Dysprosium complexes with mono-/di-carboxylate ligands-From simple dimers to 2D and 3D frameworks

NASA Astrophysics Data System (ADS)

Zhang, Yingjie; Bhadbhade, Mohan; Scales, Nicholas; Karatchevtseva, Inna; Price, Jason R.; Lu, Kim; Lumpkin, Gregory R.

2014-11-01

Four dysprosium (Dy) single carboxylates, a formate, a propionate, a butyrate and an oxalate have been synthesized and structurally characterized. The structure of Dy(HCO2)3 (1) contains nine-fold coordinated Dy polyhedra in perfect tricapped trigonal prisms. They are linked through trigonal O atoms forming 1D pillars which are further linked together through tricapped O atoms into a 3D pillared metal organic framework. The network structure is stable up to 360 °C. The structure of [Dy2(C2O4)3(H2O)6]·2.5H2O (2) contains nine-fold coordinated Dy polyhedra linking together through μ2-bridging oxalate anions into a 2D hexagonal layered structure. Both [Dy2(Pr)6(H2O)4]·(HPr)0.5 (3) [Pr=(C2H5CO2)-1] and [Dy2(Bu)6(H2O)4] (4) [Bu=(C3H7CO2)-1] have similar di-nuclear structures. The Raman vibration modes of the complexes have been investigated.

Enhanced biomimic bactericidal surfaces by coating with positively-charged ZIF nano-dagger arrays.

PubMed

Yuan, Yuan; Zhang, Yugen

2017-10-01

Cicada wing surfaces are covered with dense patterns of nano-pillar structure that prevent bacterial growth by rupturing adhered microbial cells. To mimic the natural nano-pillar structure, we developed a general and simple method to grow metal organic framework (MOF) nano-dagger arrays on a wide range of surfaces. These nano-daggers possess high bactericidal activity, with log reduction >7 for Escherichia coli and Staphylococcus aureus. It was hypothesized that the positively-charged ZIF-L nano-dagger surfaces enhance bacterial cell adhesion, facilitating selective and efficient bacteria killing by the rigid and sharp nano-dagger tips. This research provides a safe and clean antimicrobial surface technology which does not require external chemicals and will not cause drug resistance. Copyright © 2017 Elsevier Inc. All rights reserved.

Ankle salvage surgery with autologous circular pillar fibula augmentation and intramedullary hindfoot nail.

PubMed

Paul, Jochen; Barg, Alexej; Horisberger, Monika; Herrera, Mario; Henninger, Heath B; Valderrabano, Victor

2014-01-01

Tibiotalocalcaneal arthrodesis with an intramedullary hindfoot nail is an established procedure for fusion of the ankle and subtalar joints. In cases involving ankle bone loss, such as in failed total ankle replacement, it can be difficult to salvage with sufficient bone restoration stability and a physiologic leg length and avoiding below the knee amputation. In addition to the alternatives of using a structural allograft or metal bone substitution, we describe the use of autologous ipsilateral circular pillar fibula augmentation in tibiotalocalcaneal retrograde nail arthrodesis combined with a ventral (anterior) plate in a prospective series of 6 consecutive cases with a mean follow-up duration of 26 ± 9.95 (range 12 to 34) months. The 6 patients (3 female and 3 male), with a mean age of 55 ± 13.89 (range 38 to 73) years were treated with revision surgery of the ankle (1 after talectomy, 5 [83.33%] after failed ankle replacement). The visual analog scale for pain and the American Orthopaedic Foot and Ankle Society hindfoot score were used to assess functional outcome, and radiographs and computed tomography scans were used to determine the presence of fusion. All patients improved clinically from pre- to postoperatively in regard to the mean pain visual analog scale score (from 7.5 to 2.0) and American Orthopaedic Foot and Ankle Society hindfoot score (from 29 to 65 points, of an 86-point maximum for fused joints). Radiologically, no loss in the reduction or misalignment of the hindfoot was detected, and all cases fused solid. One patient (16.67%) required hardware removal. The fixation construct provided good clinical and radiologic outcomes, and we recommend it as an alternative to structural allografts or metallic bone grafts for revision ankle surgery with severe bone loss. Copyright © 2014 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Radial junction solar cells based on heterojunction with intrinsic thin layer (HIT) structure

NASA Astrophysics Data System (ADS)

Shen, Haoting

The radial junction wire array structure was previously proposed as a solar cell geometry to separate the direction of carrier collection from the direction of light absorption, thereby circumventing the need to use high quality but expensive single crystal silicon (c-Si) material that has long minority carrier diffusion lengths. The Si radial junction structure can be realized by forming radial p-n junctions on Si pillar/wire arrays that have a diameter comparable to the minority carrier diffusion length. With proper design, the Si pillar arrays are also able to enhance light trapping and thereby increase the light absorption. However, the larger junction area and surface area on the pillar arrays compared to traditional planar junction Si solar cells makes it challenging to fabricate high performance devices due an in increase in surface defects. Therefore, effective surface passivation strategies are essential for radial junction devices. Hydrogenated amorphous silicon (a-Si:H) deposited by plasma-enhanced chemical vapor deposition (PECVD) using a heterojunction with intrinsic thin layer (HIT) structure has previously been demonstrated as a very effective surface passivation layer for planar c-Si solar cells. It is therefore of interest to use a-Si:H in a HIT layer structure for radial p-n junction c-Si pillar array solar cells. This poses several challenges, however, including the need to fabricate ultra-thin a-Si:H layers conformally on high aspect ratio Si pillars, control the crystallinity at the a-Si:H/c-Si interface to yield a low interface state density and optimize the layer thicknesses, doping and contacts to yield high performance devices. This research in this thesis was aimed at developing the processing technology required to apply the HIT structure to radial junction Si pillar array solar cell devices and to evaluate the device characteristics. Initial studies focused on understanding the effects of process conditions on the growth rate and conformality of a-Si:H deposited by PECVD using SiH4 and H 2 on high aspect ratio trench structures. Experimentally, it was found that the a-Si:H growth rate increased with increasing SiH4 flow rate up to a point after which it saturated at a maximum growth rate. In addition, it was found that higher SiH4 flow rates resulted in improved thickness uniformity along the trenches. A model based on gas transport and surface reaction of SiH3 in trenches was developed and was used to explain the experimental results and predict conditions that would yield improved thickness uniformity. The knowledge gained in the PECVD deposition studies was then used to prepare HIT radial junction Si pillar array solar cell devices. Deep reactive ion etching (DRIE) was used to prepare Si pillar arrays on p-type (111) c-Si wafers. A process was developed to prepare n-type a-Si:H films from SiH 4 and H2, with PH3 as doping gas. Indium tin oxide (ITO) deposited by sputter deposition and Al-doped ZnO deposited by atomic layer deposition (ALD) were evaluated as transparent conductive top contacts to the n-type a-Si:H layer. By adjusting the SiH4/H2 gas flow ratio, intrinsic a-Si:H was grown on the c-Si surface without epitaxial micro-crystalline growth. Continuous and pulsed deposition modes were investigated for deposition of the intrinsic and n-type a-Si:H layers on the c-Si pillars. The measurements of device light performance shown that slightly lower short circuit current density (Jsc, 32 mA/cm2 to 35 mA/cm 2) but higher open circuit voltage (Voc, 0.56 V to .47 V) were obtained on the pulsed devices. As the result, higher efficiency (11.6%) was achieved on the pulsed devices (10.6% on the continuous device). The improved performance of the pulsed deposition devices was explained as arising from a higher SiH3 concentration in the initial plasma which lead to a more uniform layer thickness. Planar and radial junction Si wire array HIT solar cell devices were then fabricated and the device performance was compared. A series of p-type c-Si wafers with varying resistivity/doping density were used for this study in order to evaluate the effect of carrier diffusion length on device performance. The saturation current densities (J0) of the radial junction devices were consistently larger than that of the planar devices as a result of the larger junction area. Despite the increased leakage currents, the radial junction HIT cells exhibited similar Voc compared to the planar cells. In addition, at high doping densities (5˜1018 cm-3), the J sc (16.7mA/cm2) and collection efficiency (6.3%) of the radial junction devices was higher than that of comparable planar cells (J sc 12.7 mA/cm2 and efficiency 5.2%), demonstrating improved collection of photogenerated carriers in this geometry.

Liquid-vapor transition on patterned solid surfaces in a shear flow

NASA Astrophysics Data System (ADS)

Yao, Wenqi; Ren, Weiqing

2015-12-01

Liquids on a solid surface patterned with microstructures can exhibit the Cassie-Baxter (Cassie) state and the wetted Wenzel state. The transitions between the two states and the effects of surface topography, surface chemistry as well as the geometry of the microstructures on the transitions have been extensively studied in earlier work. However, most of these work focused on the study of the free energy landscape and the energy barriers. In the current work, we consider the transitions in the presence of a shear flow. We compute the minimum action path between the Wenzel and Cassie states using the minimum action method [W. E, W. Ren, and E. Vanden-Eijnden, Commun. Pure Appl. Math. 57, 637 (2004)]. Numerical results are obtained for transitions on a surface patterned with straight pillars. It is found that the shear flow facilitates the transition from the Wenzel state to the Cassie state, while it inhibits the transition backwards. The Wenzel state becomes unstable when the shear rate reaches a certain critical value. Two different scenarios for the Wenzel-Cassie transition are observed. At low shear rate, the transition happens via nucleation of the vapor phase at the bottom of the groove followed by its growth. At high shear rate, in contrary, the nucleation of the vapor phase occurs at the top corner of a pillar. The vapor phase grows in the direction of the flow, and the system goes through an intermediate metastable state before reaching the Cassie state.

Oxygen- and Lithium-Doped Hybrid Boron-Nitride/Carbon Networks for Hydrogen Storage.

PubMed

Shayeganfar, Farzaneh; Shahsavari, Rouzbeh

2016-12-20

Hydrogen storage capacities have been studied on newly designed three-dimensional pillared boron nitride (PBN) and pillared graphene boron nitride (PGBN). We propose these novel materials based on the covalent connection of BNNTs and graphene sheets, which enhance the surface and free volume for storage within the nanomaterial and increase the gravimetric and volumetric hydrogen uptake capacities. Density functional theory and molecular dynamics simulations show that these lithium- and oxygen-doped pillared structures have improved gravimetric and volumetric hydrogen capacities at room temperature, with values on the order of 9.1-11.6 wt % and 40-60 g/L. Our findings demonstrate that the gravimetric uptake of oxygen- and lithium-doped PBN and PGBN has significantly enhanced the hydrogen sorption and desorption. Calculations for O-doped PGBN yield gravimetric hydrogen uptake capacities greater than 11.6 wt % at room temperature. This increased value is attributed to the pillared morphology, which improves the mechanical properties and increases porosity, as well as the high binding energy between oxygen and GBN. Our results suggest that hybrid carbon/BNNT nanostructures are an excellent candidate for hydrogen storage, owing to the combination of the electron mobility of graphene and the polarized nature of BN at heterojunctions, which enhances the uptake capacity, providing ample opportunities to further tune this hybrid material for efficient hydrogen storage.

Some Characteristics of Current Star Formation in the 30 Doradus Nebula Revealed by HST/NICMOS

NASA Astrophysics Data System (ADS)

Walborn, Nolan R.; Barbá, Rodolfo H.; Brandner, Wolfgang; Rubio, Mónica; Grebel, Eva K.; Probst, Ronald G.

1999-01-01

The extensive ``second generation'' of star formation within the 30 Doradus Nebula, evidently triggered by the R136 central cluster around its periphery, has been imaged with the Near-Infrared Camera and Multi-Object Spectrometer (NICMOS) on the Hubble Space Telescope. Many new IR sources, including multiple systems, clusters, and nebular structures, are found in these images. Six of the NICMOS fields are described here, in comparison with the WFPC2 images of the same fields. Knots 1-3 of Walborn & Blades (early O stars embedded in dense nebular knots) are all found to be compact multiple systems. Knot 1 is shown to reside at the top of a massive dust pillar oriented directly toward R136, whose summit has just been removed, exposing the newborn stellar system. Knots 1 and 3 are also near the brightest IR sources in the region, while parsec-scale jet structures are discovered in association with Knots 2 and 3. The Knot 2 structures consist of detached, nonstellar IR sources aligned on either side of the stellar system, which are interpreted as impact points of a highly collimated, possibly rotating bipolar jet on the surrounding dark clouds; the H_2O maser found by Whiteoak et al. is also in this field. These outflows from young massive stars in 30 Dor are the first extragalactic examples of the phenomenon. In the field of the pillars south of R136, recently discussed in comparison with the M16 pillars by Scowen et al., a new luminous stellar IR source has been discovered. These results establish the 30 Doradus Nebula as a prime region in which to investigate the formation and very early evolution of massive stars and multiple systems. The theme of triggered formation within the heads of extensive dust pillars oriented toward R136 is strong. In addition, these results provide further insights into the global structure and evolution of 30 Doradus, which are significant in view of its status as the best resolved extragalactic starburst. This paper is dedicated to W. W. Morgan, who taught me the power of morphology to uncover new phenomena in astronomy.-N. R. W.

Biomechanical Characterization of Cardiomyocyte Using PDMS Pillar with Microgrooves

PubMed Central

Oyunbaatar, Nomin-Erdene; Lee, Deok-Hyu; Patil, Swati J.; Kim, Eung-Sam; Lee, Dong-Weon

2016-01-01

This paper describes the surface-patterned polydimethylsiloxane (PDMS) pillar arrays for enhancing cell alignment and contraction force in cardiomyocytes. The PDMS micropillar (μpillar) arrays with microgrooves (μgrooves) were fabricated using a unique micro-mold made using SU-8 double layer processes. The spring constant of the μpillar arrays was experimentally confirmed using atomic force microscopy (AFM). After culturing cardiac cells on the two different types of μpillar arrays, with and without grooves on the top of μpillar, the characteristics of the cardiomyocytes were analyzed using a custom-made image analysis system. The alignment of the cardiomyocytes on the μgrooves of the μpillars was clearly observed using a DAPI staining process. The mechanical force generated by the contraction force of the cardiomyocytes was derived from the displacement of the μpillar arrays. The contraction force of the cardiomyocytes aligned on the μgrooves was 20% higher than that of the μpillar arrays without μgrooves. The experimental results prove that applied geometrical stimulus is an effective method for aligning and improving the contraction force of cardiomyocytes. PMID:27517924

Characterization of two distinctly different mineral-related proteins from the teeth of the Camarodont sea urchin Lytechinus variegatus: Specificity of function with relation to mineralization

NASA Astrophysics Data System (ADS)

Veis, A.; Alvares, K.; Dixit, S. N.; Robach, J. S.; Stock, S. R.

2009-06-01

The majority of the mineral phase of the Lytechinus variegatus tooth is comprised of magnesium containing calcite crystal elements, collectively arranged so that they appear as a single crystal under polarized light, as well as under X-ray or electron irradiation. However, the crystal elements are small, and in spite of the common alignment of their crystal axes, are not the same size or shape in different parts of the tooth. The toughness of the tooth structure arises from the fact that it is a composite in which the crystals are coated with surface layers of organic matter that probably act to inhibit crack formation and elongation. In the growth region the organic components represent a greater part of the tooth structure. In the most heavily mineralized adoral region the primary plates fuse with inter-plate pillars. Using Scanning Electron Microscopy; TOF-SIMS mapping of the characteristic amino acids of the mineral related proteins; and isolation and characterization of the mineral-protected protein we report that the late-forming inter-plate pillars had more than a three-fold greater Mg content than the primary plates. Furthermore, the aspartic acid content of the mineralrelated protein was highest in the high Mg pillars whereas the mineral-protected protein of the primary plates was richer in glutamic acid content.These results suggest that the Asp-rich protein(s) is important for formation of the late developing inter-plate pillars that fuse the primary plates and increase the stiffness of the most mature tooth segment. Supported by NIDCR Grant DE R01-01374 to AV.

Evolution and Engineering of Precisely Controlled Ge Nanostructures on Scalable Array of Ordered Si Nano-pillars

NASA Astrophysics Data System (ADS)

Wang, Shuguang; Zhou, Tong; Li, Dehui; Zhong, Zhenyang

2016-06-01

The scalable array of ordered nano-pillars with precisely controllable quantum nanostructures (QNs) are ideal candidates for the exploration of the fundamental features of cavity quantum electrodynamics. It also has a great potential in the applications of innovative nano-optoelectronic devices for the future quantum communication and integrated photon circuits. Here, we present a synthesis of such hybrid system in combination of the nanosphere lithography and the self-assembly during heteroepitaxy. The precise positioning and controllable evolution of self-assembled Ge QNs, including quantum dot necklace(QDN), QD molecule(QDM) and quantum ring(QR), on Si nano-pillars are readily achieved. Considering the strain relaxation and the non-uniform Ge growth due to the thickness-dependent and anisotropic surface diffusion of adatoms on the pillars, the comprehensive scenario of the Ge growth on Si pillars is discovered. It clarifies the inherent mechanism underlying the controllable growth of the QNs on the pillar. Moreover, it inspires a deliberate two-step growth procedure to engineer the controllable QNs on the pillar. Our results pave a promising avenue to the achievement of desired nano-pillar-QNs system that facilitates the strong light-matter interaction due to both spectra and spatial coupling between the QNs and the cavity modes of a single pillar and the periodic pillars.

Evolution and Engineering of Precisely Controlled Ge Nanostructures on Scalable Array of Ordered Si Nano-pillars

PubMed Central

Wang, Shuguang; Zhou, Tong; Li, Dehui; Zhong, Zhenyang

2016-01-01

The scalable array of ordered nano-pillars with precisely controllable quantum nanostructures (QNs) are ideal candidates for the exploration of the fundamental features of cavity quantum electrodynamics. It also has a great potential in the applications of innovative nano-optoelectronic devices for the future quantum communication and integrated photon circuits. Here, we present a synthesis of such hybrid system in combination of the nanosphere lithography and the self-assembly during heteroepitaxy. The precise positioning and controllable evolution of self-assembled Ge QNs, including quantum dot necklace(QDN), QD molecule(QDM) and quantum ring(QR), on Si nano-pillars are readily achieved. Considering the strain relaxation and the non-uniform Ge growth due to the thickness-dependent and anisotropic surface diffusion of adatoms on the pillars, the comprehensive scenario of the Ge growth on Si pillars is discovered. It clarifies the inherent mechanism underlying the controllable growth of the QNs on the pillar. Moreover, it inspires a deliberate two-step growth procedure to engineer the controllable QNs on the pillar. Our results pave a promising avenue to the achievement of desired nano-pillar-QNs system that facilitates the strong light-matter interaction due to both spectra and spatial coupling between the QNs and the cavity modes of a single pillar and the periodic pillars. PMID:27353231

Tungstocobaltate-pillared layered double hydroxides: Preparation, characterization, magnetic and catalytic properties

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

Wei Xiaocui; Baicheng College of Higher Medicine, Baicheng 137000; Fu Youzhi

2008-06-15

A new polyoxometalate anion-pillared layered double hydroxide (LDH) was prepared by aqueous ion exchange of a Mg-Al LDH precursor in nitrate form with the tungstocobaltate anions [CoW{sub 12}O{sub 40}]{sup 5-}. The physicochemical properties of the product were characterized by the methods of powder X-ray diffraction, elemental analysis, infrared spectroscopy, thermogravimetric analysis and cyclic voltammetry. It was confirmed that [CoW{sub 12}O{sub 40}]{sup 5-} was intercalated between the brucite-type layers of the LDHs without a change in the structure. Magnetic measurement shows the occurrence of antiferromagnetic interactions between the magnetic centers. The investigation of catalytic performance for this sample exhibits high activitymore » for the oxidation of benzaldehyde by hydrogen peroxide. - Graphical abstract: A tungstocobaltate anion [CoW{sub 12}O{sub 40}]{sup 5-} pillared layered double hydroxide (LDH) was prepared by aqueous ion exchange with a Mg-Al LDH precursor in nitrate form, demonstrating that [CoW{sub 12}O{sub 40}]{sup 5-} was intercalated between the brucite-type layers of the LDHs without change in structure. Magnetic measurement shows the occurrence of antiferromagnetic interactions between the magnetic centers. The investigation of catalytic performance for this sample exhibits high activity for the oxidation of benzaldehyde by hydrogen peroxide.« less

Fabrication of Bi modified Bi2S3 pillared g-C3N4 photocatalyst and its efficient photocatalytic reduction and oxidation performances

NASA Astrophysics Data System (ADS)

Chen, Dongdong; Fang, Jianzhang; Lu, Shaoyou; Zhou, GuangYing; Feng, Weihua; Yang, Fan; Chen, Yi; Fang, ZhanQiang

2017-12-01

A novel efficient Bi modified Bi2S3 pillared g-C3N4 (BBC) plasmonic semiconductor photocatalyst has been successfully developed in a mixed solvothermal environment. The photocatalytic abilities of the as-prepared samples are examined by the photocatalytic reduction of Cr(VI) and oxidation of tetracycline (TC). And the chemical composition, structure, morphology and photo-absorption properties of the photocatalysts have been investigated by XRD, FT-IR, XPS, TEM, HRTEM and DRS methods, respectively. It is found that the addition of triethanolamine (TEA) results in the formation of the pillared-g-C3N4 (PG) nanostructure. The agglomeration of g-C3N4 nanosheets moiety and Bi2S3 nanorods moiety can be both hindered effectively by the special PG structure. And the photocatalytic results indicate that BBC exhibits the best photoreduction and photooxidation performances among all the samples, and meanwhile possesses superior photo-stability during the recycling runs. The enhanced photocatalytic activity of BBC could be ascribed to the furtherance of charge separation, localized surface plasma resonance (SPR) effect of metallic Bi and the excellent reaction interface. Finally, a tentative mechanism of BBC for photocatalytic reduction of Cr(VI) and oxidation of TC is discussed in detail.

Siting of prison complex above abandoned underground coal mine

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

Marino, G.G.

1998-10-01

This paper discusses in detail the process undertaken to mitigate the effects of any future mine subsidence on prison structures proposed above old abandoned underground workings. The site for a proposed prison complex purchased by the state of Indiana was located in west-central Indiana and was undermined by an old abandoned room and pillar mine. Based on a study of the mine map and subsurface verification of the extent of mining it was determined that all prison buildings and important structures could be placed above solid coal to the north. However, one masonry building was located within the potential drawmore » zone of mine works that still contained significant mine voids. Based on empirical data the subsidence potential was estimated and the building was designed accordingly to be mine subsidence resistant. It was decided that a phase 2 prison complex should be constructed adjacent to and just south of the phase 1 complex. This complex would be directly above the underground workings. Subsequently, an extensive subsurface investigation program was undertaken to (1) ascertain whether or not mine areas where buildings would be located were already collapsed and thus only nominal, if any, subsidence could occur in the future and (2) verify the presence of solid coal areas within the mine as indicated on the mine map. Based on all the site information gathered subsidence profiles were developed from an empirical database of subsidence events in the Illinois coal basin. As a result of this work many structures on the site required no or nominal subsidence considerations. However, for others that could be affected potentially by future subsidence movement preliminary subsidence resistant designs were completed using the expected level of potential subsidence movement.« less

Vertically aligned P(VDF-TrFE) core-shell structures on flexible pillar arrays

PubMed Central

Choi, Yoon-Young; Yun, Tae Gwang; Qaiser, Nadeem; Paik, Haemin; Roh, Hee Seok; Hong, Jongin; Hong, Seungbum; Han, Seung Min; No, Kwangsoo

2015-01-01

PVDF and P(VDF-TrFE) nano- and micro- structures have been widely used due to their potential applications in several fields, including sensors, actuators, vital sign transducers, and energy harvesters. In this study, we developed vertically aligned P(VDF-TrFE) core-shell structures using high modulus polyurethane acrylate (PUA) pillars as the support structure to maintain the structural integrity. In addition, we were able to improve the piezoelectric effect by 1.85 times from 40 ± 2 to 74 ± 2 pm/V when compared to the thin film counterpart, which contributes to the more efficient current generation under a given stress, by making an effective use of the P(VDF-TrFE) thin top layer as well as the side walls. We attribute the enhancement of piezoelectric effects to the contributions from the shell component and the strain confinement effect, which was supported by our modeling results. We envision that these organic-based P(VDF-TrFE) core-shell structures will be used widely as 3D sensors and power generators because they are optimized for current generations by utilizing all surface areas, including the side walls of core-shell structures. PMID:26040539

Vertically aligned P(VDF-TrFE) core-shell structures on flexible pillar arrays

DOE PAGES

Choi, Yoon-Young; Yun, Tae Gwang; Qaiser, Nadeem; ...

2015-06-04

PVDF and P(VDF-TrFE) nano- and micro- structures are widely used due to their potential applications in several fields, including sensors, actuators, vital sign transducers, and energy harvesters. In this study, we developed vertically aligned P(VDF-TrFE) core-shell structures using high modulus polyurethane acrylate (PUA) pillars as the support structure to maintain the structural integrity. In addition, we were able to improve the piezoelectric effect by 1.85 times from 40 ± 2 to 74 ± 2 pm/V when compared to the thin film counterpart, which contributes to the more efficient current generation under a given stress, by making an effective use ofmore » the P(VDF-TrFE) thin top layer as well as the side walls. We attribute the enhancement of piezoelectric effects to the contributions from the shell component and the strain confinement effect, which was supported by our modeling results. We envision that these organic-based P(VDF-TrFE) core-shell structures will be used widely as 3D sensors and power generators because they are optimized for current generations by utilizing all surface areas, including the side walls of core-shell structures.« less

Tuning micropillar tapering for optimal friction performance of thermoplastic gecko-inspired adhesive.

PubMed

Kim, Yongkwan; Chung, Yunsie; Tsao, Angela; Maboudian, Roya

2014-05-14

We present a fabrication method and friction testing of a gecko-inspired thermoplastic micropillar array with control over the tapering angle of the pillar sidewall. A combination of deep reactive ion etching of vertical silicon pillars and subsequent maskless chemical etching produces templates with various widths and degrees of taper, which are then replicated with low-density polyethylene. As the silicon pillars on the template are chemically etched in a bath consisting of hydrofluoric acid, nitric acid, and acetic acid (HNA), the pillars are progressively thinned, then shortened. The replicated polyethylene pillar arrays exhibit a corresponding increase in friction as the stiffness is reduced with thinning and then a decrease in friction as the stiffness is again increased. The dilution of the HNA bath in water influences the tapering angle of the silicon pillars. The friction of the replicated pillars is maximized for the taper angle that maximizes the contact area at the tip which in turn is influenced by the stiffness of the tapered pillars. To provide insights on how changes in microscale geometry and contact behavior may affect friction of the pillar array, the pillars are imaged by scanning electron microscopy after friction testing, and the observed deformation behavior from shearing is related to the magnitude of the macroscale friction values. It is shown that the tapering angle critically changes the pillar compliance and the available contact area. Simple finite element modeling calculations are performed to support that the observed deformation is consistent with what is expected from a mechanical analysis. We conclude that friction can be maximized via proper pillar tapering with low stiffness that still maintains enough contact area to ensure high adhesion.

Stigmergic construction and topochemical information shape ant nest architecture

PubMed Central

Khuong, Anaïs; Gautrais, Jacques; Perna, Andrea; Sbaï, Chaker; Combe, Maud; Kuntz, Pascale; Jost, Christian; Theraulaz, Guy

2016-01-01

The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture. PMID:26787857

Stigmergic construction and topochemical information shape ant nest architecture.

PubMed

Khuong, Anaïs; Gautrais, Jacques; Perna, Andrea; Sbaï, Chaker; Combe, Maud; Kuntz, Pascale; Jost, Christian; Theraulaz, Guy

2016-02-02

The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture.

Phenol hydroxylation on Al-Fe modified-bentonite: Effect of Fe loading, temperature and reaction time

NASA Astrophysics Data System (ADS)

Widi, R. K.; Budhyantoro, A.; Christianto, A.

2017-11-01

The present work reflects the study of the phenol hydroxylation reactions to synthesize hydroquinone and catechol on Al-Fe modified-bentonite. This study started with synthesizes the catalyst material based on the modified bentonite. Natural bentonite from Pacitan, Indonesia was intercalated with Cetyl-TetramethylammoniumBromida (CTMA-Br) followed by pillarization using Alumina. The pillared bentonite was then impregnated with Fe solution (0.01 M, 0.05 M, and 0.1 M). The solid material obtained was calcined at 723 K for 4 hours. All the materials were characterized using BET N2 adsorption. Their catalytic activity and selectivity were studied for phenol hydroxylation using H2O2 (30%). The reaction conditions of this reaction were as follows: ratio of phenol/H2O2 = 1:1 (molar ratio), concentration of phenol = 1 M and ratio of catalyst/phenol was 1:10. Reaction temperatures were varied at 333, 343 and 353 K. The reaction time was also varied at 3, 4 and 5 hours. The result shows that the materials have potential catalyst activity.

Droplet sliding on inclined superhydrophobic surfaces: the effect of anisotropic contact line

NASA Astrophysics Data System (ADS)

Jiang, Youhua; Cao, Lile; Guo, Zongqi; Choi, Chang-Hwan

2017-11-01

Although the effects of solid structures on droplet retention on superhydrophobic surfaces have been studied extensively, the investigation has been restricted to the sessile droplets on horizontal surfaces where the contact line motions are axisymmetric or isotropic (either advancing or receding). In the droplet retention on inclined surfaces, the contact line motions are asymmetric or anisotropic; the advancing and receding motions coexist. In this study, we investigate the correlation between the droplet boundary pinning and the surface morphology on inclined superhydrophobic surfaces. The evolution of the droplet contact angle and width show contrary behaviors between pillar- and pore-structured surfaces due to the distinctive microscopic contact line motions. Therefore, the visualizations of the contact line motions at different locations of the boundary on inclined superhydrophobic surfaces are performed and the averaged contact line density of the boundary is quantified. The result shows that the droplet retentive force monotonously increase with the increase in contact line density, regardless of the surface morphological types, dimensions, or the direction of contact line motion (advancing, receding, or both). The result indicates that the droplet retentive force on superhydrophobic surfaces is mainly determined by the contact line density, regardless of the isotropy of the contact line.

3D gate-all-around bandgap-engineered SONOS flash memory in vertical silicon pillar with metal gate

NASA Astrophysics Data System (ADS)

Oh, Jae-Sub; Yang, Seong-Dong; Lee, Sang-Youl; Kim, Young-Su; Kang, Min-Ho; Lim, Sung-Kyu; Lee, Hi-Deok; Lee, Ga-Won

2013-08-01

In this paper, a gate-all-around bandgap-engineered silicon-oxide-nitride-oxide-silicon device with a vertical silicon pillar structure and a Ti metal gate are demonstrated for a potential solution to overcome the scaling-down of flash memory device. The devices were fabricated using CMOS-compatible technology and exhibited well-behaved memory characteristics in terms of the program/erase window, retention, and endurance properties. Moreover, the integration of the Ti metal gate demonstrated a significant improvement in the erase characteristics due to the efficient suppression of the electron back tunneling through the blocking oxide.

Large Deformation Characteristics and Reinforcement Measures for a Rock Pillar in the Houziyan Underground Powerhouse

NASA Astrophysics Data System (ADS)

Xiao, Xin-hong; Xiao, Pei-wei; Dai, Feng; Li, Hai-bo; Zhang, Xue-bin; Zhou, Jia-wen

2018-02-01

The underground powerhouse of the Houziyan Hydropower Station is under the conditions of high geo-stress and a low strength/stress ratio, which leads to significant rock deformation and failures, especially for rock pillars due to bidirectional unloading during the excavation process. Damages occurred in thinner rock pillars after excavation due to unloading and stress concentration, which will reduce the surrounding rock integrity and threaten the safety of the underground powerhouse. By using field investigations and multi-source monitoring data, the deformation and failure characteristics of a rock pillar are analyzed from the tempo-spatial distribution features. These results indicate that significant deformation occurred in the rock pillar when the powerhouse was excavated to the fourth layer, and the maximum displacement reached 107.57 mm, which occurred on the main transformer chamber upstream sidewall at an elevation of 1721.20 m. The rock deformation surrounding the rock pillar is closely related to the excavation process and has significant time-related characteristics. To control large deformation of the rock pillar, thru-anchor cables were used to reinforce the rock pillar to ensure the stability of the powerhouse. The rock deformation surrounding the rock pillar decreases gradually and forms a convergent trend after reinforcement measures are installed based on the analysis of the temporal characteristics and the rock pillar deformation rate.

Replication of cicada wing's nano-patterns by hot embossing and UV nanoimprinting.

PubMed

Hong, Sung-Hoon; Hwang, Jaeyeon; Lee, Heon

2009-09-23

The hydrophobicity of the cicada wing originates from its naturally occurring, surface nano-structure. The nano-structure of the cicada wing consists of an array of nano-sized pillars, 100 nm in diameter and 300 nm in height. In this study, the nano-structure of the cicada wing was successfully duplicated by using hot embossing lithography and UV nanoimprint lithography (NIL). The diameter and pitch of replication were the same as those of the original cicada wing and the height was a little smaller than that of the original master. The transmittance of the hot embossed PVC film was increased by 2-6% compared with that of the bare PVC film. The hydrophobicity was measured by water contact angle measurements. The water contact angle of the replica, made of UV cured polymer, was 132 degrees +/- 2 degrees , which was slightly lower than that of the original cicada wing (138 degrees +/- 2 degrees ), but much higher than that of the UV cured polymer surface without any nano-sized pillars (86 degrees ).

Path-programmable water droplet manipulations on an adhesion controlled superhydrophobic surface

PubMed Central

Seo, Jungmok; Lee, Seoung-Ki; Lee, Jaehong; Seung Lee, Jung; Kwon, Hyukho; Cho, Seung-Woo; Ahn, Jong-Hyun; Lee, Taeyoon

2015-01-01

Here, we developed a novel and facile method to control the local water adhesion force of a thin and stretchable superhydrophobic polydimethylsiloxane (PDMS) substrate with micro-pillar arrays that allows the individual manipulation of droplet motions including moving, merging and mixing. When a vacuum pressure was applied below the PDMS substrate, a local dimple structure was formed and the water adhesion force of structure was significantly changed owing to the dynamically varied pillar density. With the help of the lowered water adhesion force and the slope angle of the formed dimple structure, the motion of individual water droplets could be precisely controlled, which facilitated the creation of a droplet-based microfluidic platform capable of a programmable manipulation of droplets. We showed that the platform could be used in newer and emerging microfluidic operations such as surface-enhanced Raman spectroscopy with extremely high sensing capability (10−15 M) and in vitro small interfering RNA transfection with enhanced transfection efficiency of ~80%. PMID:26202206

Three-Dimensional Hetero-Integration of Faceted GaN on Si Pillars for Efficient Light Energy Conversion Devices.

PubMed

Kim, Dong Rip; Lee, Chi Hwan; Cho, In Sun; Jang, Hanmin; Jeon, Min Soo; Zheng, Xiaolin

2017-07-25

An important pathway for cost-effective light energy conversion devices, such as solar cells and light emitting diodes, is to integrate III-V (e.g., GaN) materials on Si substrates. Such integration first necessitates growth of high crystalline III-V materials on Si, which has been the focus of many studies. However, the integration also requires that the final III-V/Si structure has a high light energy conversion efficiency. To accomplish these twin goals, we use single-crystalline microsized Si pillars as a seed layer to first grow faceted Si structures, which are then used for the heteroepitaxial growth of faceted GaN films. These faceted GaN films on Si have high crystallinity, and their threading dislocation density is similar to that of GaN grown on sapphire. In addition, the final faceted GaN/Si structure has great light absorption and extraction characteristics, leading to improved performance for GaN-on-Si light energy conversion devices.

Dysprosium complexes with mono-/di-carboxylate ligands—From simple dimers to 2D and 3D frameworks

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

Zhang, Yingjie, E-mail: yzx@ansto.gov.au; Bhadbhade, Mohan; Scales, Nicholas

2014-11-15

Four dysprosium (Dy) single carboxylates, a formate, a propionate, a butyrate and an oxalate have been synthesized and structurally characterized. The structure of Dy(HCO{sub 2}){sub 3} (1) contains nine-fold coordinated Dy polyhedra in perfect tricapped trigonal prisms. They are linked through trigonal O atoms forming 1D pillars which are further linked together through tricapped O atoms into a 3D pillared metal organic framework. The network structure is stable up to 360 °C. The structure of [Dy{sub 2}(C{sub 2}O{sub 4}){sub 3}(H{sub 2}O){sub 6}]·2.5H{sub 2}O (2) contains nine-fold coordinated Dy polyhedra linking together through μ{sub 2}-bridging oxalate anions into a 2D hexagonalmore » layered structure. Both [Dy{sub 2}(Pr){sub 6}(H{sub 2}O){sub 4}]·(HPr){sub 0.5} (3) [Pr=(C{sub 2}H{sub 5}CO{sub 2}){sup −1}] and [Dy{sub 2}(Bu){sub 6}(H{sub 2}O){sub 4}] (4) [Bu=(C{sub 3}H{sub 7}CO{sub 2}){sup −1}] have similar di-nuclear structures. The Raman vibration modes of the complexes have been investigated. - Graphical abstract: Four dysprosium (Dy) complexes with formate, propionate, butyrate and oxalate ligands have been synthesized and characterized. The Dy formato complex has a 3D pillared metal organic framework and the structure is stable up to 360 °C whilst the complexes with longer alkyl chained mono-carboxylates possess similar di-nuclear structures. The Dy oxalato complex has a 2D hexagonal (honeycomb-type) structure. Their Raman vibration modes have been investigated. - Highlights: • New Dysprosium complexes with formate, propionate, butyrate and oxalate ligands. • Crystal structures range from dimers to two and three dimensional frameworks. • Vibrational modes have been investigated and correlated to the structures. • The complexes are thermal robust and stable to over 300 °C.« less

Fabrication method to create high-aspect ratio pillars for photonic coupling of board level interconnects

NASA Astrophysics Data System (ADS)

Debaes, C.; Van Erps, J.; Karppinen, M.; Hiltunen, J.; Suyal, H.; Last, A.; Lee, M. G.; Karioja, P.; Taghizadeh, M.; Mohr, J.; Thienpont, H.; Glebov, A. L.

2008-04-01

An important challenge that remains to date in board level optical interconnects is the coupling between the optical waveguides on printed wiring boards and the packaged optoelectronics chips, which are preferably surface mountable on the boards. One possible solution is the use of Ball Grid Array (BGA) packages. This approach offers a reliable attachment despite the large CTE mismatch between the organic FR4 board and the semiconductor materials. Collimation via micro-lenses is here typically deployed to couple the light vertically from the waveguide substrate to the optoelectronics while allowing for a small misalignment between board and package. In this work, we explore the fabrication issues of an alternative approach in which the vertical photonic connection between board and package is governed by a micro-optical pillar which is attached both to the board substrate and to the optoelectronic chips. Such an approach allows for high density connections and small, high-speed detector footprints while maintaining an acceptable tolerance between board and package. The pillar should exhibit some flexibility and thus a high-aspect ratio is preferred. This work presents and compares different fabrication methods and applies different materials for such high-aspect ratio pillars. The different fabrication methods are: photolithography, direct laser writing and deep proton writing. The selection of optical materials that was investigated is: SU8, Ormocers, PU and a multifunctional acrylate polymer. The resulting optical pillars have diameters ranging from 20um up to 80um, with total heights ranging between 30um and 100um (symbol for micron). The aspect-ratio of the fabricated structures ranges from 1.5 to 5.

Thickness limitations in carbon nanotube reinforced silicon nitride coatings synthesized by vapor infiltration

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

Eres, Gyula

Chemical vapor infiltration is a convenient method for synthesizing carbon nanotube (CNT)-reinforced ceramic coatings. The thickness over which infiltration is relatively uniform is limited by gas phase diffusion in the pore structure. These effects were investigated in two types of silicon nitride matrix composites. With CNTs that were distributed uniformly on the substrate surface dense coatings were limited to thicknesses of several microns. With dual structured CNT arrays produced by photolithography coatings up to 400 gm thick were obtained with minimal residual porosity. Gas transport into these dual structured materials was facilitated by creating micron sized channels between "CNT pillars"more » (i.e. each pillar consisted of a large number of individual CNTs). The experimental results are consistent with basic comparisons between the rates of gas diffusion and silicon nitride growth in porous structures. This analysis also provides a general insight into optimizing infiltration conditions during the fabrication of thick CNT-reinforced composite coatings. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.« less

Role of the H-containing groups on the structural dynamics of Ti3C2Tx MXene

NASA Astrophysics Data System (ADS)

Wen, Jing; Zhang, Xitian; Gao, Hong

2018-05-01

It is a confused problem in the literature that the c-axis value of Ti3C2 MXene changes with the synthesis procedure, but the part of the surface structures that plays the role of pillar to support the Ti3C2 layers and their variation rules remain controversial. In this work, we develop the structure models and formation mechanisms of Ti3C2Tx based on the density functional theory calculations and experimental results. While the c-axis values of the samples vary from about 1.9 to 2.9 nm, the corresponding pillars are determined by different distributions and proportions of the H-containing groups. The proportions of the H-containing groups that determine the c-axis value are formulated as the functions of the interlayer space, which can be used to quantitatively clarify the changes of the surface functional groups after the samples experiencing different treatments. The results can facilitate the in situ detections of the surface structures of MXenes during different treatments or electrochemical processes.

Eccentricity effect of micropatterned surface on contact angle.

PubMed

Kashaninejad, Navid; Chan, Weng Kong; Nguyen, Nam-Trung

2012-03-13

This article experimentally shows that the wetting property of a micropatterned surface is a function of the center-to-center offset distance between successive pillars in a column, referred to here as eccentricity. Studies were conducted on square micropatterns which were fabricated on a silicon wafer with pillar eccentricity ranging from 0 to 6 μm for two different pillar diameters and spacing. Measurement results of the static as well as the dynamic contact angles on these surfaces revealed that the contact angle decreases with increasing eccentricity and increasing relative spacing between the pillars. Furthermore, quantification of the contact angle hysteresis (CAH) shows that, for the case of lower pillar spacing, CAH could increase up to 41%, whereas for the case of higher pillar spacing, this increment was up to 35%, both corresponding to the maximum eccentricity of 6 μm. In general, the maximum obtainable hydrophobicity corresponds to micropillars with zero eccentricity. As the pillar relative spacing decreases, the effect of eccentricity on hydrophobicity becomes more pronounced. The dependence of the wettability conditions of the micropatterned surface on the pillar eccentricity is attributed to the contact line deformation resulting from the changed orientation of the pillars. This finding provides additional insights in design and fabrication of efficient micropatterned surfaces with controlled wetting properties.

Spin frustration in a family of pillared kagomé layers of high-spin cobalt(II) ions.

PubMed

Wang, Long-Fei; Li, Cui-Jin; Chen, Yan-Cong; Zhang, Ze-Min; Liu, Jiang; Lin, Wei-Quan; Meng, Yan; Li, Quan-Wen; Tong, Ming-Liang

2015-02-02

Based on the analogous kagomé [Co3 (imda)2 ] layers (imda=imidazole-4,5-dicarboxylate), a family of pillar-layered frameworks with the formula of [Co3 (imda)2 (L)3 ]⋅(L)n ⋅xH2 O (1: L=pyrazine, n=0, x=8; 2: L=4,4'-bipyridine, n=1, x=8; 3: L=1,4-di(pyridin-4-yl)benzene, n=1, x=13; 4: L=4,4'-di(pyridin-4-yl)-1,1'-biphenyl, n=1, x=14) have been successfully synthesized by a hydrothermal/solvothermal method. Single-crystal structural analysis shows a significant increase in the interlayer distances synchronized with the extension of the pillar ligands, namely, 7.092(3) (1), 10.921(6) (2), 14.780(5) (3), and 19.165(4) Å (4). Despite the wrinkled kagomé layers in complexes 2-4, comprehensive magnetic characterizations revealed weakening of interlayer magnetic interactions and an increase in the degree of frustration as the pillar ligand becomes longer from 1 to 4; this leads to characteristic magnetic ground states. For compound 4, which has the longest interlayer distance, the interlayer interaction is so weak that the magnetic properties observed within the range of temperature measured would correspond to the frustrated layer. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shear Adhesion of Tapered Nanopillar Arrays.

PubMed

Cho, Younghyun; Minsky, Helen K; Jiang, Yijie; Yin, Kaiyang; Turner, Kevin T; Yang, Shu

2018-04-04

Tapered nanopillars with various cross sections, including cone-shaped, stepwise, and pencil-like structures (300 nm in diameter at the base of the pillars and 1.1 μm in height), are prepared from epoxy resin templated by nanoporous anodic aluminum oxide (AAO) membranes. The effect of pillar geometry on the shear adhesion behavior of these nanopillar arrays is investigated via sliding experiments in a nanoindentation system. In a previous study of arrays with the same geometry, it was shown that cone-shaped nanopillars exhibit the highest adhesion under normal loading while stepwise and pencil-like nanopillars exhibit lower normal adhesion strength due to significant deformation of the pillars that occurs with increasing indentation depth. Contrary to the previous studies, here, we show that pencil-like nanopillars exhibit the highest shear adhesion strength at all indentation depths among three types of nanopillar arrays and that the shear adhesion increases with greater indentation depth due to the higher bending stiffness and closer packing of the pencil-like nanopillar array. Finite element simulations are used to elucidate the deformation of the pillars during the sliding experiments and agree with the nanoindentation-based sliding measurements. The experiments and finite element simulations together demonstrate that the shape of the nanopillars plays a key role in shear adhesion and that the mechanism is quite different from that of adhesion under normal loading.

Pretest reference calculation for the Heated Axisymmetric Pillar (WIPP Room H in situ experiment)

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

Morgan, H.S.; Stone, C.M.

A pretest reference calculation for the Heated Axisymmetric Pillar or Room H experiment is presented in this report. The Heated Axisymmetric Pillar is one of several large scale in situ experiments currently under construction near Carlsbad, New Mexico, at the site of the Waste Isolation Pilot Plant (WIPP). This test is an intermediate step in validating numerical techniques for design and performance calculations for radioactive waste repositories in salt. The test consists of a cylindrically shaped pillar, centrally located in an annular drift, which is uniformly heated by blanket heaters. These heaters produce a thermal output of 135 W/m/sup 2/.more » This load will be supplied for a period of three years. Room H is heavily instrumented for monitoring both temperature increases due to the thermal loading and deformations due to creep of the salt. Data from the experiment are not available at the present time, but the measurements for Room H will eventually be compared to the calculation presented in this report to assess and improve thermal and mechanical modeling capabilities for the WIPP. The thermal/structural model used in the calculation represents the state of the art at the present time. A large number of plots are included since an appropriate result is required for every Room H gauge location. 56 refs., 97 figs., 4 tabs.« less

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

Abdelbaky, Mohammed S.M.; Amghouz, Zakariae; Department of Materials Science and Metallurgical Engineering, University of Oviedo, Campus Universitario, 33203 Gijón

Novel metal phosphonate [CuLi(PPA)] [H{sub 3}PPA=3-phosphonopropionic acid] was synthesized hydrothermally and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, scanning electron microscopy, infrared spectroscopy, and thermogravimetric analysis. It crystallizes in the space group C2/c, with cell parameters a=21.617(2) Å, b=4.9269(2) Å, c=14.342(1) Å, β=132.3(2)°, and Z=8. Its framework is built up from a main trimer, acting as a secondary building unit (SBU), which is formed by vertex-shared between two (LiO{sub 4}) and one (Cu(1)O{sub 4}) polyhedra. These units repeat along b-axis forming infinite inorganic chains, these chains are in turn cross-linked by corner sharing with (Cu(2)O{sub 4}) polyhedra to producemore » inorganic layers lying in the bc-plane. The neighboring layers are connected through the PPA ligand, leading to a 3D pillared-layered structure. The topological analysis reveals that the compound exhibits 3,4,10-c net. Finally, magnetic susceptibility measurement of this compound over the temperature range of 2–300 K reveals the occurrence of weak antiferromagnetic intrachain interactions. - Graphical abstract: Hydrothermal synthesis and structural characterization of a novel lithium-copper phosphonate, formulated as [CuLi(PPA)] (H{sub 3}PPA=3-phosphonopropionic acid), have been reported. This compound has a 3D pillared-layered structure with 3,4,10-c net topology. The magnetic susceptibility data over the temperature range of 2–300 K reveals the occurrence of weak antiferromagnetic interactions. - Highlights: • Novel metal phosphonate, [CuLi(PPA)] (1), has been synthesized and characterized. • Compound 1 has a 3D pillared-layered structure with 3,4,10-c net topology. • Magnetic susceptibility data reveals the occurrence of weak antiferromagnetic interactions.« less

Dielectric anomaly and relaxation natures in a Zn-Cr pillar−layered metal−organic framework with cages and channels

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

Xue, Chen; Yao, Zhi-Yuan; Liu, Shao-Xian

A bimetallic metal–organic framework (MOF) with the formula [Zn{sub 3}btc{sub 2}(Cr{sub 3}O(isonic){sub 6}(H{sub 2}O){sub 2}(OH))]·(DMF){sub 15.5}(H{sub 2}O){sub 8} (H{sub 3}btc=1,3,5-benzenetricarboxylic acid; isonic=isonicotinicate) shows a pillar-layered structure. The monolayer consists of hexagon-like rings formed by the [Zn(isonic){sub 2}(btc){sub 2}] tetrahedral and the consecutive monolayers are pillared by trigonal–prismatic clusters of [Cr{sub 3}O(isonic){sub 6}(H{sub 2}O){sub 2}(OH)]through the remaining binding sites of the Zn{sup 2+} ions. DMF and water molecules are confined in the cages and channels. TGA indicates that the lattice DMF and water molecules begin to be released at temperatures above 363 K. Dielectric measurements were carried out in the rangemore » of 173–363 K and 1–10{sup 7} Hz for three successive thermal cycles. The dielectric spectroscopy obtained in the first thermal cycle was different from that observed in the next two thermal cycles, while the dielectric spectra in the last two thermal cycles were almost identical. The dielectric nature of this MOF is discussed in detail for each thermal cycle. Since MOFs are unique host–guest systems in which the structure of the host framework is designable and the guests are exchangeable, it is no doubt those MOFs are materials with a variety of dielectric natures. This study gives a fresh impetus to achieve MOFs–based dielectric materials. - Graphical abstract: The bimetallic MOF [Zn{sub 3}btc{sub 2}(Cr{sub 3}O(isonic){sub 6}(H{sub 2}O){sub 2}(OH))]·(DMF){sub 15.5}(H{sub 2}O){sub 8}1, shows a pillar-layered open-framework structure. The dielectric spectra of 1 are almost identical in the last two thermal cycles, whereas significantly different from that observed in the first thermal cycle. The novel dielectric anomaly associated with a stacked structure transformation of the disordered guests. - Highlights: • A bimetallic metal-organic framework shows a pillar-layered structure. • The MOF displays novel dielectric anomaly and relaxation behaviors. • The dielectric anomaly arises from the stacking structure transformation of guests. • The dielectric relaxation is related to the dipole dynamics of guests.« less

Bioinspired design and interfacial failure of biomedical systems

NASA Astrophysics Data System (ADS)

Rahbar, Nima

The deformation mechanism of nacre as a model biological material is studied in this project. A numerical model is presented which consists of tensile pillars, shear pillars, asperities and aragonite platelets. It has been shown that the tensile pillars are the main elements that control the global stiffness of the nacre structure. Meanwhile, ultimate strength of the nacre structure is controlled by asperities and their behavior and the ratio of L/2D which is itself a function of the geometry of the platelets. Protein/shear pillars provide the glue which holds the assembly of entire system together, particularly in the direction normal to the platelets main axis. This dissertation also presents the results of a combined theoretical/computational and experimental effort to develop crack resistant dental multilayers that are inspired by the functionally graded dento-enamel junction (DEJ) structure that occurs between dentin and enamel in natural teeth. The complex structures of natural teeth and ceramic crowns are idealized using at layered configurations. The potential effects of occlusal contact are then modeled using finite element simulations of Hertzian contact. The resulting stress distributions are compared for a range of possible bioinspired, functionally graded architecture. The computed stress distributions show that the highest stress concentrations in the top ceramic layer of crown structures are reduced significantly by the use of bioinspired functionally graded architectures. The reduced stresses are shown to be associated with significant improvements (30%) in the pop-in loads over a wide range of clinically-relevant loading rates. The implications of the results are discussed for the design of bioinspired dental ceramic crown structures. The results of a combined experimental and computational study of mixed mode fracture in glass/cement and zirconia/cement interfaces that are relevant to dental restorations is also presented. The interfacial fracture is investigated using Brazil-nut specimens. The kinking in-and-out of the interface that occurs between glass/cement and zirconia/cement interfaces, is also shown to be consistent with predictions from a microstructure-based finite element model. The predictions are later verified using focused ion beam and scanning electron microscopy images. Finally, the adhesion between layers that are relevant to drug-eluting stents is explored. Brazil disk specimens were used to measure the interfacial fracture energies between the layers of a model drug eluting stent over a wide range of mode mixities. The trends in the overall fracture energies are predicted using a combination of adhesion theories and fracture mechanics concepts. The measured interfacial fracture energies are shown to be in good agreement with the predictions.

Effective bichromatic potential for ultra-high Q-factor photonic crystal slab cavities

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

Alpeggiani, Filippo, E-mail: filippo.alpeggiani01@ateneopv.it; Andreani, Lucio Claudio; Gerace, Dario

2015-12-28

We introduce a confinement mechanism in photonic crystal slab cavities, which relies on the superposition of two incommensurate one-dimensional lattices in a line-defect waveguide. It is shown that the resulting photonic profile realizes an effective quasi-periodic bichromatic potential for the electromagnetic field confinement yielding extremely high quality (Q) factor nanocavities, while simultaneously keeping the mode volume close to the diffraction limit. We apply these concepts to pillar- and hole-based photonic crystal slab cavities, respectively, and a Q-factor improvement by over an order of magnitude is shown over existing designs, especially in pillar-based structures. Thanks to the generality and easy adaptationmore » of such confinement mechanism to a broad class of cavity designs and photonic lattices, this work opens interesting routes for applications where enhanced light–matter interaction in photonic crystal structures is required.« less

Supramolecular Drug Delivery Systems Based on Water-Soluble Pillar[n]arenes.

PubMed

Wu, Xuan; Gao, Lei; Hu, Xiao-Yu; Wang, Leyong

2016-06-01

Supramolecular drug delivery systems (SDDSs), including various kinds of nanostructures that are assembled by reversible noncovalent interactions, have attracted considerable attention as ideal drug carriers owing to their fascinating ability to undergo dynamic switching of structure, morphology, and function in response to various external stimuli, which provides a flexible and robust platform for designing and developing functional and smart supramolecular nano-drug carriers. Pillar[n]arenes represent a new generation of macrocyclic hosts, which have unique structures and excellent properties in host-guest chemistry. This account describes recent progress in our group to develop pillararene-based stimuli-responsive supramolecular nanostructures constructed by reversible host-guest interactions for controllable anticancer drug delivery. The potential applications of these supramolecular drug carriers in cancer treatment and the fundamental questions facing SDDSs are also discussed. © 2016 The Chemical Society of Japan & Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

30 CFR 75.386 - Final mining of pillars.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Final mining of pillars. 75.386 Section 75.386... MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Ventilation § 75.386 Final mining of pillars. When only one mine opening is available due to final mining of pillars, no more than 20 miners at a time shall...

Indoor localization using magnetic fields

NASA Astrophysics Data System (ADS)

Pathapati Subbu, Kalyan Sasidhar

Indoor localization consists of locating oneself inside new buildings. GPS does not work indoors due to multipath reflection and signal blockage. WiFi based systems assume ubiquitous availability and infrastructure based systems require expensive installations, hence making indoor localization an open problem. This dissertation consists of solving the problem of indoor localization by thoroughly exploiting the indoor ambient magnetic fields comprising mainly of disturbances termed as anomalies in the Earth's magnetic field caused by pillars, doors and elevators in hallways which are ferromagnetic in nature. By observing uniqueness in magnetic signatures collected from different campus buildings, the work presents the identification of landmarks and guideposts from these signatures and further develops magnetic maps of buildings - all of which can be used to locate and navigate people indoors. To understand the reason behind these anomalies, first a comparison between the measured and model generated Earth's magnetic field is made, verifying the presence of a constant field without any disturbances. Then by modeling the magnetic field behavior of different pillars such as steel reinforced concrete, solid steel, and other structures like doors and elevators, the interaction of the Earth's field with the ferromagnetic fields is described thereby explaining the causes of the uniqueness in the signatures that comprise these disturbances. Next, by employing the dynamic time warping algorithm to account for time differences in signatures obtained from users walking at different speeds, an indoor localization application capable of classifying locations using the magnetic signatures is developed solely on the smart phone. The application required users to walk short distances of 3-6 m anywhere in hallway to be located with accuracies of 80-99%. The classification framework was further validated with over 90% accuracies using model generated magnetic signatures representing hallways with different kinds of pillars, doors and elevators. All in all, this dissertation contributes the following: 1) provides a framework for understanding the presence of ambient magnetic fields indoors and utilizing them to solve the indoor localization problem; 2) develops an application that is independent of the user and the smart phones and 3) requires no other infrastructure since it is deployed on a device that encapsulates the sensing, computing and inferring functionalities, thereby making it a novel contribution to the mobile and pervasive computing domain.

Three Philosophical Pillars That Support Collaborative Learning.

ERIC Educational Resources Information Center

Maltese, Ralph

1991-01-01

Discusses three philosophical pillars that support collaborative learning: "spaces of appearance," active engagement, and ownership. Describes classroom experiences with collaborative learning supported by these pillars. (PRA)

Pillar cuvettes: capillary-filled, microliter quartz cuvettes with microscale path lengths for optical spectroscopy.

PubMed

Holzner, Gregor; Kriel, Frederik Hermanus; Priest, Craig

2015-05-05

The goal of most analytical techniques is to reduce the lower limit of detection; however, it is sometimes necessary to do the opposite. High sample concentrations or samples with high molar absorptivity (e.g., dyes and metal complexes) often require multiple dilution steps or laborious sample preparation prior to spectroscopic analysis. Here, we demonstrate dilution-free, one-step UV-vis spectroscopic analysis of high concentrations of platinum(IV) hexachloride in a micropillar array, that is, "pillar cuvette". The cuvette is spontaneously filled by wicking of the liquid sample into the micropillar array. The pillar height (thus, the film thickness) defines the optical path length, which was reduced to between 10 and 20 μm in this study (3 orders of magnitude smaller than in a typical cuvette). Only one small droplet (∼2 μL) of sample is required, and the dispensed volume need not be precise or even known to the analyst for accurate spectroscopy measurements. For opaque pillars, we show that absorbance is linearly related to platinum concentration (the Beer-Lambert Law). For fully transparent or semitransparent pillars, the measured absorbance was successfully corrected for the fractional surface coverage of the pillars and the transmittance of the pillars and reference. Thus, both opaque and transparent pillars can be applied to absorbance spectroscopy of high absorptivity, microliter samples. It is also shown here that the pillar array has a useful secondary function as an integrated (in-cuvette) filter for particulates. For pillar cuvette measurements of platinum solutions spiked with 6 μm diameter polystyrene spheres, filtered and unfiltered samples gave identical spectra.

Numerical Approach for Goaf-Side Entry Layout and Yield Pillar Design in Fractured Ground Conditions

NASA Astrophysics Data System (ADS)

Jiang, Lishuai; Zhang, Peipeng; Chen, Lianjun; Hao, Zhen; Sainoki, Atsushi; Mitri, Hani S.; Wang, Qingbiao

2017-11-01

Entry driven along goaf-side (EDG), which is the development of an entry of the next longwall panel along the goaf-side and the isolation of the entry from the goaf with a small-width yield pillar, has been widely employed in China over the past several decades . The width of such a yield pillar has a crucial effect on EDG layout in terms of the ground control, isolation effect and resource recovery rate. Based on a case study, this paper presents an approach for evaluating, designing and optimizing EDG and yield pillar by considering the results from numerical simulations and field practice. To rigorously analyze the ground stability, the numerical study begins with the simulation of goaf-side stress and ground conditions. Four global models with identical conditions, except for the width of the yield pillar, are built, and the effect of pillar width on ground stability is investigated by comparing aspects of stress distribution, failure propagation, and displacement evolution during the entire service life of the entry. Based on simulation results, the isolation effect of the pillar acquired from field practice is also considered. The suggested optimal yield pillar design is validated using a field test in the same mine. Thus, the presented numerical approach provides references and can be utilized for the evaluation, design and optimization of EDG and yield pillars under similar geological and geotechnical circumstances.

A Reconstructed Vision of Environmental Science Literacy: The case of Qatar

NASA Astrophysics Data System (ADS)

Khishfe, Rola

2014-12-01

The purpose of this study was twofold: (a) develop a conceptual framework for environmental science literacy; and consequently (b) examine the potential of science standards/curricula to prepare environmentally literate citizens. The framework comprised four pillars: science content knowledge, scientific inquiry, nature of science (NOS), and socioscientific issues (SSI). A conceptual understanding of these pillars as interconnected was presented and justified. Then the developed framework was used to examine the potential of the Qatari science standards to prepare environmentally literate citizens. Results showed that the secondary Qatari science standards generally take up the pillars of science content and scientific inquiry in an explicit manner. The NOS pillar is rarely addressed, while the SSI pillar is not addressed in the objectives and activities in a way that aligns with the heavy emphasis given in the overall aims. Moreover, the connections among pillars are mostly manifested within the activities and between the science content and scientific inquiry. The objectives and activities targeting the environment were less frequent among the four pillars across the Qatari standards. Again, the connections related to the environment were less frequent in conformity with the limited environmental objectives and activities. Implications from this study relate to the need for the distribution of the four pillars across the standards as well as the presentation of the different pillars as interconnected.

Thermal conductivity of pillared graphene-epoxy nanocomposites using molecular dynamics

NASA Astrophysics Data System (ADS)

Lakshmanan, A.; Srivastava, S.; Ramazani, A.; Sundararaghavan, V.

2018-04-01

Thermal conductivity in a pillared graphene-epoxy nanocomposite (PGEN) is studied using equilibrium molecular dynamics simulations. PGEN is a proposed material for advanced thermal management applications because it combines high in-plane conductivity of graphene with high axial conductivity of a nanotube to significantly enhance the overall conductivity of the epoxy matrix material. Anisotropic conductivity of PGEN has been compared with that of pristine and functionalized carbon nanotube-epoxy nanocomposites, showcasing the advantages of the unique hierarchical structure of PGEN. Compared to pure carbon allotropes, embedding the epoxy matrix also promotes a weaker dependence of conductivity on thermal variations. These features make this an attractive material for thermal management applications.

Manufacture of high aspect ratio micro-pillar wall shear stress sensor arrays

NASA Astrophysics Data System (ADS)

Gnanamanickam, Ebenezer P.; Sullivan, John P.

2012-12-01

In the field of experimental fluid mechanics the measurement of unsteady, distributed wall shear stress has proved historically challenging. Recently, sensors based on an array of flexible micro-pillars have shown promise in carrying out such measurements. Similar sensors find use in other applications such as cellular mechanics. This work presents a manufacturing technique that can manufacture micro-pillar arrays of high aspect ratio. An electric discharge machine (EDM) is used to manufacture a micro-drilling tool. This micro-drilling tool is used to form holes in a wax sheet which acts as the mold for the micro-pillar array. Silicone rubber is cast in these molds to yield a micro-pillar array. Using this technique, micro-pillar arrays with a maximum aspect ratio of about 10 have been manufactured. Manufacturing issues encountered, steps to alleviate them and the potential of the process to manufacture similar micro-pillar arrays in a time-efficient manner are also discussed.

SiGe nano-heteroepitaxy on Si and SiGe nano-pillars.

PubMed

Mastari, M; Charles, M; Bogumilowicz, Y; Thai, Q M; Pimenta-Barros, P; Argoud, M; Papon, A M; Gergaud, P; Landru, D; Kim, Y; Hartmann, J M

2018-07-06

In this paper, SiGe nano-heteroepitaxy on Si and SiGe nano-pillars was investigated in a 300 mm industrial reduced pressure-chemical vapour deposition tool. An integration scheme based on diblock copolymer patterning was used to fabricate nanometre-sized templates for the epitaxy of Si and SiGe nano-pillars. Results showed highly selective and uniform processes for the epitaxial growth of Si and SiGe nano-pillars. 200 nm thick SiGe layers were grown on Si and SiGe nano-pillars and characterised by atomic force microscopy, x-ray diffraction and transmission electron microscopy. Smooth SiGe surfaces and full strain relaxation were obtained in the 650 °C-700 °C range for 2D SiGe layers grown either on Si or SiGe nano-pillars.

Length scale selects directionality of droplets on vibrating pillar ratchet

DOE PAGES

Agapov, Rebecca L.; Boreyko, Jonathan B.; Briggs, Dayrl P.; ...

2014-09-22

Directional control of droplet motion at room temperature is of interest for applications such as microfluidic devices, self-cleaning coatings, and directional adhesives. Here, arrays of tilted pillars ranging in height from the nanoscale to the microscale are used as structural ratchets to directionally transport water at room temperature. Water droplets deposited on vibrating chips with a nanostructured ratchet move preferentially in the direction of the feature tilt while the opposite directionality is observed in the case of microstructured ratchets. This remarkable switch in directionality is consistent with changes in the contact angle hysteresis. To glean further insights into the lengthmore » scale dependent asymmetric contact angle hysteresis, the contact lines formed by a nonvolatile room temperature ionic liquid placed onto the tilted pillar arrays were visualized and analyzed in situ in a scanning electron microscope. As a result, the ability to tune droplet directionality by merely changing the length scale of surface features all etched at the same tilt angle would be a versatile tool for manipulating multiphase flows and for selecting droplet directionality in other lap-on-chip applications.« less

Modeling plastic deformation of post-irradiated copper micro-pillars

NASA Astrophysics Data System (ADS)

Crosby, Tamer; Po, Giacomo; Ghoniem, Nasr M.

2014-12-01

We present here an application of a fundamentally new theoretical framework for description of the simultaneous evolution of radiation damage and plasticity that can describe both in situ and ex situ deformation of structural materials [1]. The theory is based on the variational principle of maximum entropy production rate; with constraints on dislocation climb motion that are imposed by point defect fluxes as a result of irradiation. The developed theory is implemented in a new computational code that facilitates the simulation of irradiated and unirradiated materials alike in a consistent fashion [2]. Discrete Dislocation Dynamics (DDD) computer simulations are presented here for irradiated fcc metals that address the phenomenon of dislocation channel formation in post-irradiated copper. The focus of the simulations is on the role of micro-pillar boundaries and the statistics of dislocation pinning by stacking-fault tetrahedra (SFTs) on the onset of dislocation channel and incipient surface crack formation. The simulations show that the spatial heterogeneity in the distribution of SFTs naturally leads to localized plastic deformation and incipient surface fracture of micro-pillars.

The siting of a prison complex above an abandoned underground coal mine

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

Marino, G.G.

1997-12-31

This paper discusses in detail the process undertaken to mitigate the effects of any future mine subsidence on prison structures proposed above old abandoned underground workings. The site for a proposed prison complex purchased by the State of Indiana was located in west-central Indiana and was undermined by an old abandoned room and pillar mine. The original plan for construction consisted of one phase. Based on a study of the mine map and subsurface verification of the extent of mining it was determined that all prison buildings and important structures could be placed above solid coal to the north. Onemore » masonry building, however, was located within the potential draw zone of mine works which still contained significant mine voids. Based on empirical data the subsidence potential was estimated and the building was accordingly designed to be mine subsidence resistant. It was decided that a phase two prison complex should be constructed adjacent to and just south of the Phase I complex. This complex would be directly above the underground workings. The first stage of design was to minimize subsidence potential by positioning the exposure of significant structures to the subjacent mining assuming the mine map was sufficiently accurate. Subsequently, an extensive subsurface investigation program was then undertaken to: (1) ascertain whether or not mine areas where buildings would be located were already collapsed and thus only nominal, if any, subsidence could occur in the future; and (2) verify the presence of solid coal areas within the mine as indicated on the mine map. Based on all the site information gathered subsidence profiles were developed from an empirical data base of subsidence events in the Illinois Coal Basin. As a result of this work many structures on the site required no or nominal subsidence considerations.« less

Optimization of pillar electrodes in subretinal prosthesis for enhanced proximity to target neurons

NASA Astrophysics Data System (ADS)

Flores, Thomas; Lei, Xin; Huang, Tiffany; Lorach, Henri; Dalal, Roopa; Galambos, Ludwig; Kamins, Theodore; Mathieson, Keith; Palanker, Daniel

2018-06-01

Objective. High-resolution prosthetic vision requires dense stimulating arrays with small electrodes. However, such miniaturization reduces electrode capacitance and penetration of electric field into tissue. We evaluate potential solutions to these problems with subretinal implants based on utilization of pillar electrodes. Approach. To study integration of three-dimensional (3D) implants with retinal tissue, we fabricated arrays with varying pillar diameter, pitch, and height, and implanted beneath the degenerate retina in rats (Royal College of Surgeons, RCS). Tissue integration was evaluated six weeks post-op using histology and whole-mount confocal fluorescence imaging. The electric field generated by various electrode configurations was calculated in COMSOL, and stimulation thresholds assessed using a model of network-mediated retinal response. Main results. Retinal tissue migrated into the space between pillars with no visible gliosis in 90% of implanted arrays. Pillars with 10 μm height reached the middle of the inner nuclear layer (INL), while 22 μm pillars reached the upper portion of the INL. Electroplated pillars with dome-shaped caps increase the active electrode surface area. Selective deposition of sputtered iridium oxide onto the cap ensures localization of the current injection to the pillar top, obviating the need to insulate the pillar sidewall. According to computational model, pillars having a cathodic return electrode above the INL and active anodic ring electrode at the surface of the implant would enable six times lower stimulation threshold, compared to planar arrays with circumferential return, but suffer from greater cross-talk between the neighboring pixels. Significance. 3D electrodes in subretinal prostheses help reduce electrode-tissue separation and decrease stimulation thresholds to enable smaller pixels, and thereby improve visual acuity of prosthetic vision.

Control of proliferation and osteogenic differentiation of human dental-pulp-derived stem cells by distinct surface structures.

PubMed

Kolind, K; Kraft, D; Bøggild, T; Duch, M; Lovmand, J; Pedersen, F S; Bindslev, D A; Bünger, C E; Foss, M; Besenbacher, F

2014-02-01

The ability to control the behavior of stem cells provides crucial benefits, for example, in tissue engineering and toxicity/drug screening, which utilize the stem cell's capacity to engineer new tissues for regenerative purposes and the testing of new drugs in vitro. Recently, surface topography has been shown to influence stem cell differentiation; however, general trends are often difficult to establish due to differences in length scales, surface chemistries and detailed surface topographies. Here we apply a highly versatile screening approach to analyze the interplay of surface topographical parameters on cell attachment, morphology, proliferation and osteogenic differentiation of human mesenchymal dental-pulp-derived stem cells (DPSCs) cultured with and without osteogenic differentiation factors in the medium (ODM). Increasing the inter-pillar gap size from 1 to 6 μm for surfaces with small pillar sizes of 1 and 2 μm resulted in decreased proliferation and in more elongated cells with long pseudopodial protrusions. The same alterations of pillar topography, up to an inter-pillar gap size of 4 μm, also resulted in enhanced mineralization of DPSCs cultured without ODM, while no significant trend was observed for DPSCs cultured with ODM. Generally, cells cultured without ODM had a larger deposition of osteogenic markers on structured surfaces relative to the unstructured surfaces than what was found when culturing with ODM. We conclude that the topographical design of biomaterials can be optimized for the regulation of DPSC differentiation and speculate that the inclusion of ODM alters the ability of the cells to sense surface topographical cues. These results are essential in order to transfer the use of this highly proliferative, easily accessible stem cell into the clinic for use in cell therapy and regenerative medicine. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Irradiated interfaces in the Ara OB1, Carina, Eagle Nebula, and Cyg OB2 massive star formation regions

DOE PAGES

Hartigan, P.; Palmer, J.; Cleeves, L. I.

2012-09-05

Regions of massive star formation offer some of the best and most easily-observed examples of radiation hydrodynamics. Boundaries where fully-ionized H II regions transition to neutral/molecular photodissociation regions (PDRs) are of particular interest because marked temperature and density contrasts across the boundaries lead to evaporative flows and fluid dynamical instabilities that can evolve into spectacular pillar-like structures. Furthermore, when detached from their parent clouds, pillars become ionized globules that often harbor one or more young stars. H2 molecules at the interface between a PDR and an H II region absorb ultraviolet light from massive stars, and the resulting fluoresced infraredmore » emission lines are an ideal way to trace this boundary independent of obscuring dust. This paper presents H2 images of four regions of massive star formation that illustrate different types of PDR boundaries. The Ara OB1 star formation region contains a striking long wall that has several wavy structures which are present in H2, but the emission is not particularly bright because the ambient UV fluxes are relatively low. In contrast, the Carina star formation region shows strong H2 fluorescence both along curved walls and at the edges of spectacular pillars that in some cases have become detached from their parent clouds. The less-spectacular but more well-known Eagle Nebula has two regions that have strong fluorescence in addition to its pillars. And while somewhat older than the other regions, Cyg OB2 has the highest number of massive stars of the regions surveyed and contains many isolated, fluoresced globules that have head–tail morphologies which point towards the sources of ionizing radiation. Our images provide a collection of potential astrophysical analogs that may relate to ablated interfaces observed in laser experiments of radiation hydrodynamics.« less

Three-dimensional graphene-polypyrrole hybrid electrochemical actuator

NASA Astrophysics Data System (ADS)

Liu, Jia; Wang, Zhi; Zhao, Yang; Cheng, Huhu; Hu, Chuangang; Jiang, Lan; Qu, Liangti

2012-11-01

The advancement of mechanical actuators benefits from the development of new structural materials with prominent properties. A novel three-dimensional (3D) hydrothermally converted graphene and polypyrrole (G-PPy) hybrid electrochemical actuator is presented, which is prepared via a convenient hydrothermal process, followed by in situ electropolymerization of pyrrole. The 3D pore-interconnected G-PPy pillar exhibits strong actuation responses superior to pure graphene and PPy film. In response to the low potentials of +/-0.8 V, the saturated strain of 3D G-PPy pillar can reach a record of 2.5%, which is more than 10 times higher than that of carbon nanotube film and about 3 times that of unitary graphene film under an applied potential of +/-1.2 V. Also, the 3D G-PPy actuator exhibits high actuation durability with high operating load as demonstrated by an 11 day continuous measurement. Finally, a proof-of-concept application of 3D G-PPy as smart filler for on/off switch is also demonstrated, which indicates the great potential of the 3D G-PPy structure developed in this study for advanced actuator systems.The advancement of mechanical actuators benefits from the development of new structural materials with prominent properties. A novel three-dimensional (3D) hydrothermally converted graphene and polypyrrole (G-PPy) hybrid electrochemical actuator is presented, which is prepared via a convenient hydrothermal process, followed by in situ electropolymerization of pyrrole. The 3D pore-interconnected G-PPy pillar exhibits strong actuation responses superior to pure graphene and PPy film. In response to the low potentials of +/-0.8 V, the saturated strain of 3D G-PPy pillar can reach a record of 2.5%, which is more than 10 times higher than that of carbon nanotube film and about 3 times that of unitary graphene film under an applied potential of +/-1.2 V. Also, the 3D G-PPy actuator exhibits high actuation durability with high operating load as demonstrated by an 11 day continuous measurement. Finally, a proof-of-concept application of 3D G-PPy as smart filler for on/off switch is also demonstrated, which indicates the great potential of the 3D G-PPy structure developed in this study for advanced actuator systems. Electronic supplementary information (ESI) available: Experimental setup for fabrication of G-PPy hybrid structure, and movie showing the on/off response of G-PPy filler. See DOI: 10.1039/c2nr32699j

Host-Guest Complexes of Carboxylated Pillar[n]arenes With Drugs.

PubMed

Wheate, Nial J; Dickson, Kristie-Ann; Kim, Ryung Rae; Nematollahi, Alireza; Macquart, René B; Kayser, Veysel; Yu, Guocan; Church, W Bret; Marsh, Deborah J

2016-12-01

Pillar[n]arenes are a new family of nanocapsules that have shown application in a number of areas, but because of their poor water solubility their biomedical applications are limited. Recently, a method of synthesizing water-soluble pillar[n]arenes was developed. In this study, carboxylated pillar[n]arenes (WP[n], n = 6 or 7) have been examined for their ability to form host-guest complexes with compounds relevant to drug delivery and biodiagnostic applications. Both pillar[n]arenes form host-guest complexes with memantine, chlorhexidine hydrochloride, and proflavine by 1 H nuclear magnetic resonance and modeling. Binding is stabilized by hydrophobic effects within the cavities, and hydrogen bonding and electrostatic interactions at the portals. Encapsulation within WP[6] results in the complete and efficient quenching of proflavine fluorescence, giving rise to "on" and "off" states that have potential in biodiagnostics. The toxicity of the pillar[n]arenes was examined using in vitro growth assays with the OVCAR-3 and HEK293 cell lines. The pillar[n]arenes are relatively nontoxic to cells except at high doses and after prolonged continuous exposure. Overall, the results show that there could be a potentially large range of medical applications for carboxylated pillar[n]arene nanocapsules. Copyright © 2016 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.

Steel skin - SMC laminate structures for lightweight automotive manufacturing

NASA Astrophysics Data System (ADS)

Quagliato, Luca; Jang, Changsoon; Murugesan, Mohanraj; Kim, Naksoo

2017-09-01

In the present research work an innovative material, made of steel skin and sheet molding compound core, is presented and is aimed to be utilized for the production of automotive body frames. For a precise description of the laminate structure, the material properties of all the components, including the adhesive utilized as an interlayer, have been carried out, along with the simple tension test of the composite material. The result have shown that the proposed laminate structure has a specific yield strength 114% higher than 6061 T6 aluminum, 34% higher than 7075 T6 aluminum, 186% higher than AISI 304 stainless steel (30HRC) and 42% than SK5 high-strength steel (52HRC), showing its reliability and convenience for the realization of automotive components. After calibrating the material properties of the laminate structure, and utilizing as reference the simple tension results of the laminate structure, the derived material properties have been utilized for the simulation of the mechanical behavior of an automotive B-pillar. The results have been compared with those of a standard B-pillar made of steel, showing that the MS-SMC laminate structure manifests load and impact carry capacity comparable with those of high strength steel, while granting, at least, an 11% weight reduction.

Bentonite modification with pillarization method using metal stannum

NASA Astrophysics Data System (ADS)

Widjaya, Robert R.; Juwono, Ariadne L.; Rinaldi, Nino

2017-11-01

Clay minerals have received considerable attention in the last years because of their environmental compatibility, low cost, high selectivity, and operational simplicity. Although clays are very useful for many application in the field of catalysis, they have main disadvantage: their lack of pore volume and spesific surface area. Porosity and stability of these materials are improved by pillaring the clay layers with SnCl4, which leads to materials known as pillared clays (PILC). This research aims were to characterize the Bentonite and Sn-Bentonite as catalysts for cracking and oligomerization. The Sn-Bentonite was prepared by pillarization method with a variation in metal ratio of 5 mmol dan 10 mmol.gr-1 of bentonit. The catalyst characterized by X-ray Diffraction, X-ray Fluorescence, Fourier Transform Infra Red, Brunauer Emmett Teller, Thermogravimetric Analysis. The results showed that the Sn-Bentonite catalyst had large basal spacing and good porous structure, and the specific surface areas increased. XRF detected the Sn in the Bentonite and TGA results showed the ability Sn-Bentonite in receiving heat. FTIR test showed two type of acidity, broansted and lewis acid. The characterized results indicated that Sn-Bentonite with metal ratio 5 mmol.gr-1 better than Sn-Bentonite with metal ratio 10 mmol.gr-1, in which there was a significant increase the basal spacings, specific surface area, and pore volume. The TGA results for Sn-Bentonite appeared to be more thermally stable than Bentonite.

Solving the critical thermal bowing in 3C-SiC/Si(111) by a tilting Si pillar architecture

NASA Astrophysics Data System (ADS)

Albani, Marco; Marzegalli, Anna; Bergamaschini, Roberto; Mauceri, Marco; Crippa, Danilo; La Via, Francesco; von Känel, Hans; Miglio, Leo

2018-05-01

The exceptionally large thermal strain in few-micrometers-thick 3C-SiC films on Si(111), causing severe wafer bending and cracking, is demonstrated to be elastically quenched by substrate patterning in finite arrays of Si micro-pillars, sufficiently large in aspect ratio to allow for lateral pillar tilting, both by simulations and by preliminary experiments. In suspended SiC patches, the mechanical problem is addressed by finite element method: both the strain relaxation and the wafer curvature are calculated at different pillar height, array size, and film thickness. Patches as large as required by power electronic devices (500-1000 μm in size) show a remarkable residual strain in the central area, unless the pillar aspect ratio is made sufficiently large to allow peripheral pillars to accommodate the full film retraction. A sublinear relationship between the pillar aspect ratio and the patch size, guaranteeing a minimal curvature radius, as required for wafer processing and micro-crack prevention, is shown to be valid for any heteroepitaxial system.

Replication of cicada wing's nano-patterns by hot embossing and UV nanoimprinting

NASA Astrophysics Data System (ADS)

Hong, Sung-Hoon; Hwang, Jaeyeon; Lee, Heon

2009-09-01

The hydrophobicity of the cicada wing originates from its naturally occurring, surface nano-structure. The nano-structure of the cicada wing consists of an array of nano-sized pillars, 100 nm in diameter and 300 nm in height. In this study, the nano-structure of the cicada wing was successfully duplicated by using hot embossing lithography and UV nanoimprint lithography (NIL). The diameter and pitch of replication were the same as those of the original cicada wing and the height was a little smaller than that of the original master. The transmittance of the hot embossed PVC film was increased by 2-6% compared with that of the bare PVC film. The hydrophobicity was measured by water contact angle measurements. The water contact angle of the replica, made of UV cured polymer, was 132° ± 2°, which was slightly lower than that of the original cicada wing (138° ± 2°), but much higher than that of the UV cured polymer surface without any nano-sized pillars (86°).

Characterization of electronic structures from CdS/Si nanoheterostructure array based on silicon nanoporous pillar array

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

Li, Yong, E-mail: liyong@pdsu.edu.cn; Song, Xiao Yan; Song, Yue Li

2016-02-15

Highlights: • CdS/Si nanoheterostructure array has been fabricated through a CBD method. • The electronic properties have been investigated by the I–V and C–V techniques. • The onset voltages, characteristic frequency and built-in potential are investigated. • The electronic structures can be tuned through the annealing treatments. - Abstract: The electronic properties of heterostructures are very important to its applications in the field of optoelectronic devices. Understanding and control of electronic properties are very necessary. CdS/Si nanoheterostructure array have been fabricated through growing CdS nanocrystals on the silicon nanoporous pillar array using a chemical bath deposition method. The electronic propertiesmore » of CdS nanoheterostructure array have been investigated by the current–voltage, complex impedance spectroscopy and capacitance–voltage techniques. The onset voltages, characteristic frequency and built-in potential are gradually increased with increasing the annealing temperature. It is indicated that the electronic structures of CdS/Si nanoheterostructure array can be tuned through the annealing treatments.« less

Structured-gate organic field-effect transistors

NASA Astrophysics Data System (ADS)

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

2012-06-01

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

Controllable synthesis and optical properties of novel ZnO cone arrays via vapor transport at low temperature.

PubMed

Han, Xinhai; Wang, Guanzhong; Jie, Jiansheng; Choy, Wallace C H; Luo, Yi; Yuk, T I; Hou, J G

2005-02-24

Novel ZnO cone arrays with controllable morphologies have been synthesized on silicon (100) substrates by thermal evaporation of metal Zn powder at a low temperature of 570 degrees C without a metal catalyst. Clear structure evolutions were observed using scanning electron microscopy: well-aligned ZnO nanocones, double-cones with growing head cones attached by stem cones, and cones with straight hexagonal pillar were obtained as the distance between the source and the substrates was increased. X-ray diffraction shows that all cone arrays grow along the c-axis. Raman and photoluminescence spectra reveal that the optical properties of the buffer layer between the ZnO cone arrays and the silicon substrates are better than those of the ZnO cone arrays due to high concentration of Zn in the heads of the ZnO cone arrays and higher growth temperature of the buffer layer. The growth of ZnO arrays reveals that the cone arrays are synthesized through a self-catalyzed vapor-liquid-solid (VLS) process.

Measurement of fracture toughness by nanoindentation methods: Recent advances and future challenges

DOE PAGES

Sebastiani, Marco; Johanns, K. E.; Herbert, Erik G.; ...

2015-04-30

In this study, we describe recent advances and developments for the measurement of fracture toughness at small scales by the use of nanoindentation-based methods including techniques based on micro-cantilever beam bending and micro-pillar splitting. A critical comparison of the techniques is made by testing a selected group of bulk and thin film materials. For pillar splitting, cohesive zone finite element simulations are used to validate a simple relationship between the critical load at failure, the pillar radius, and the fracture toughness for a range of material properties and coating/substrate combinations. The minimum pillar diameter required for nucleation and growth ofmore » a crack during indentation is also estimated. An analysis of pillar splitting for a film on a dissimilar substrate material shows that the critical load for splitting is relatively insensitive to the substrate compliance for a large range of material properties. Experimental results from a selected group of materials show good agreement between single cantilever and pillar splitting methods, while a discrepancy of ~25% is found between the pillar splitting technique and double-cantilever testing. It is concluded that both the micro-cantilever and pillar splitting techniques are valuable methods for micro-scale assessment of fracture toughness of brittle ceramics, provided the underlying assumptions can be validated. Although the pillar splitting method has some advantages because of the simplicity of sample preparation and testing, it is not applicable to most metals because their higher toughness prevents splitting, and in this case, micro-cantilever bend testing is preferred.« less

Effects of pictorially-defined surfaces on visual search.

PubMed

Morita, Hiromi; Kumada, Takatsune

2003-08-01

Three experiments of visual search for a cube (for a square pillar in Experiment 3) with an odd conjunction of orientation of faces and color (a cube with a red top face and a green right face among cubes with a green top face and a red right face, for example) showed that the search is made more efficient by arranging cubes (or square pillars) so that their top faces lie in a horizontal surface defined by pictorial cues. This effect shows the same asymmetry as that of the surface defined by the disparity cue did [Perception and Psychophysics, 62 (2000) 540], implying that the effect is independent of the three-dimensional cue and the global surface structure influences the control of attention during the search.

Non-ultraviolet-based patterning of polymer structures by optically induced electrohydrodynamic instability

NASA Astrophysics Data System (ADS)

Wang, Feifei; Yu, Haibo; Liu, Na; Mai, John D.; Liu, Lianqing; Lee, Gwo-Bin; Jung Li, Wen

2013-11-01

We report here an approach to rapidly construct organized formations of micron-scale pillars from a thin polydimethylsiloxane (PDMS) film by optically induced electrohydrodynamic instability (OEHI). In OEHI, a heterogeneous electric field is induced across two thin fluidic layers by stimulating a photoconductive thin film in a parallel-plate capacitor configuration with visible light. We demonstrated that this OEHI method could control nucleation sites of pillars formed by electrohydrodynamic instability. To investigate this phenomenon, a tangential electric force component is assumed to have arisen from the surface polarization charge and is introduced into the traditional perfect dielectric model for PDMS films. Numerical simulation results showed that this tangential electric force played an important role in OEHI.

Combination of photogrammetric and geoelectric methods to assess 3d structures associated to natural hazards

NASA Astrophysics Data System (ADS)

Fargier, Yannick; Dore, Ludovic; Antoine, Raphael; Palma Lopes, Sérgio; Fauchard, Cyrille

2016-04-01

The extraction of subsurface materials is a key element for the economy of a nation. However, natural degradation of underground quarries is a major issue from an economic and public safety point of view. Consequently, the quarries stakeholders require relevant tools to define hazards associated to these structures. Safety assessment methods of underground quarries are recent and mainly based on rock physical properties. This kind of method leads to a certain homogeneity assumption of pillar internal properties that can cause an underestimation of the risk. Electrical Resistivity Imaging (ERI) is a widely used method that possesses two advantages to overcome this limitation. The first is to provide a qualitative understanding for the detection and monitoring of anomalies in the pillar body (e.g. faults). The second is to provide a quantitative description of the electrical resistivity distribution inside the pillar. This quantitative description can be interpreted with constitutive laws to help decision support (water content decreases the mechanical resistance of a chalk). However, conventional 2D and 3D Imaging techniques are usually applied to flat surface surveys or to surfaces with moderate topography. A 3D inversion of more complex media (case of the pillar) requires a full consideration of the geometry that was never taken into account before. The Photogrammetric technique presents a cost effective solution to obtain an accurate description of the external geometry of a complex media. However, this method has never been fully coupled with a geophysical method to enhance/improve the inversion process. Consequently we developed a complete procedure showing that photogrammetric and ERI tools can be efficiently combined to assess a complex 3D structure. This procedure includes in a first part a photogrammetric survey, a processing stage with an open source software and a post-processing stage finalizing a 3D surface model. The second part necessitates the production of a complete 3D mesh of the previous surface model to operate some forward modelization of the geo-electrical problem. To solve the inverse problem and obtain a 3D resistivity distribution we use a double grid method associated with a regularized Gauss-Newton inversion scheme. We applied this procedure to a synthetic case to demonstrate the impact of the geometry on the inversion result. This study shows that geometrical information in between electrodes are necessary to reconstruct finely the "true model". Finally, we apply the methodology to a real underground quarry pillar, implying one photogrammetric survey and three ERI surveys. The results show that the procedure can greatly improve the reconstruction and avoid some artifacts due to strong geometry variations.

HUBBLE'S PANORAMIC PORTRAIT OF A VAST STAR-FORMING REGION

NASA Technical Reports Server (NTRS)

2002-01-01

NASA's Hubble Space Telescope has snapped a panoramic portrait of a vast, sculpted landscape of gas and dust where thousands of stars are being born. This fertile star-forming region, called the 30 Doradus Nebula, has a sparkling stellar centerpiece: the most spectacular cluster of massive stars in our cosmic neighborhood of about 25 galaxies. The mosaic picture shows that ultraviolet radiation and high-speed material unleashed by the stars in the cluster, called R136 [the large blue blob left of center], are weaving a tapestry of creation and destruction, triggering the collapse of looming gas and dust clouds and forming pillar-like structures that are incubators for nascent stars. The photo offers an unprecedented, detailed view of the entire inner region of 30 Doradus, measuring 200 light-years wide by 150 light-years high. The nebula resides in the Large Magellanic Cloud (a satellite galaxy of the Milky Way), 170,000 light-years from Earth. Nebulas like 30 Doradus are the 'signposts' of recent star birth. High-energy ultraviolet radiation from the young, hot, massive stars in R136 causes the surrounding gaseous material to glow. Previous Hubble telescope observations showed that R136 contains several dozen of the most massive stars known, each about 100 times the mass of the Sun and about 10 times as hot. These stellar behemoths all formed at the same time about 2 million years ago. The stars in R136 are producing intense 'stellar winds' (streams of material traveling at several million miles an hour), which are wreaking havoc on the gas and dust in the surrounding neighborhood. The winds are pushing the gas away from the cluster and compressing the inner regions of the surrounding gas and dust clouds [the pinkish material]. The intense pressure is triggering the collapse of parts of the clouds, producing a new generation of star formation around the central cluster. The new stellar nursery is about 30 to 50 light-years from R136. Most of the stars in the nursery are not visible because they are still encased in their cocoons of gas and dust. Some of the nascent stars are forming in long columns of gas and dust. Previous Hubble observations revealed that the process of 'triggered' star formation often involves massive pillars of material that point toward the central cluster. Such pillars form when particularly dense clouds of gas and dust shield columns of material behind them from the blistering radiation and strong winds released by massive stars, like the stars in R136. This protected material becomes the pillars where stars can form and grow. The Hubble telescope first spied these pillars of stellar creation when it captured close-up views of the Eagle Nebula. The new image of 30 Doradus shows numerous pillars -- each about several light-years long -- oriented toward the central cluster. These pillars, which resemble tiny fingers, are similar in size to those in the Eagle Nebula. Without Hubble's resolution, they would not be visible. One pillar is visible within the oval-shaped structure to the left of the cluster. Two [one dark and one bright] are next to each other below and to the right of the cluster. One pillar is at upper right, and still another is just above the cluster. Newborn stars within most of these pillars already have been discovered in pictures taken by Hubble's infrared camera, the Near Infrared Camera and Multi-Object Spectrometer, which can penetrate the dust to detect embryonic stars. Eventually, intense radiation and stellar winds from the developing stars will blow off the tops of the pillars. The Hubble image shows that one such eruption already has occurred in 30 Doradus. A trio of young stars has just been 'born' by breaking out of its natal pillar. These new stars are just a few hundred thousand years old. In another 2 million years, the new generation of stars will be in full bloom. But the massive stars in R136 will have burned themselves out. And the nebula's central region will be a giant shell, devoid of gas and dust. Still later, all of the most massive stars and gas will have disappeared from the entire region. Only older, less massive stars will remain in a region cleared of gas and dust. The mosaic image of 30 Doradus consists of five overlapping pictures taken between January 1994 and September 2000 by Hubble's Wide Field and Planetary Camera 2. Several color filters were used to enhance important details in the stars and the nebula. Blue corresponds to the hot stars. The greenish color denotes hot gas energized by the central cluster of stars. Pink depicts the glowing edges of the gas and dust clouds facing the cluster, which are being bombarded by winds and radiation. Reddish-brown represents the cooler surfaces of the clouds, which are not receiving direct radiation from the central cluster. Credits: NASA, N. Walborn and J. Ma`iz-Apell`aniz (Space Telescope Science Institute, Baltimore, MD), R. Barb`a (La Plata Observatory, La Plata, Argentina)

Three d10 coordination polymers assembled from 3,5-bis(imidazole-1-yl)pyridine and different polycarboxylates: Syntheses, structures and luminescence properties

NASA Astrophysics Data System (ADS)

Pan, Jie; Zhang, Di; Xue, Zhen-Zhen; Wei, Li; Han, Song-De; Wang, Guo-Ming

2017-11-01

Three novel Zn(II)/Cd(II) coordination polymers, [Cd2(bip)2(m-bdc)2(H2O)2·3H2O]n (1), [Zn2(bip)2(p-bdc)2·2.5H2O]n (2) and [Zn(bip) (p-bdc)·3H2O]n (3), where bip = 3,5-bis(imidazole-1-yl)pyridine, m-H2bdc = 1,3-benzenedicarboxylic acid, p-H2bdc = 1,4-benzenedicarboxylic acid, have been successfully synthesized under solvothermal conditions. The linkage of different ligands with Cd(II) ions in compound 1 affords a (3,5)-connected layer. Furthermore, 2D→3D parallel polycatenation occurs wherein the layers are polycatenated with the adjacent two parallel layers to form a 3D framework. In 2 and 3, the polycarboxylates act as pillars to combine the metal-bip chains, yielding the layered structures. These 2D networks are extended to the final 3D supramolecular architectures by π-π stacking interactions. The results show that bip can act as a versatile building block for the construction of various coordination polymers. Moreover, the fluorescent properties of 1-3 in the solid state at room temperature have been investigated.

Pillar size optimization design of isolated island panel gob-side entry driving in deep inclined coal seam—case study of Pingmei No. 6 coal seam

NASA Astrophysics Data System (ADS)

Zhang, Shuai; Wang, Xufeng; Fan, Gangwei; Zhang, Dongsheng; Jianbin, Cui

2018-06-01

There is a perception that deep roadways are difficult to maintain. To reverse this and to improve the recovery rate of coal resources, gob-side entry driving is widely used in coal mines, especially deep-mining coal mines, in China. Determination of the reasonable pillar size through in situ observation and experimentation plays a vital role for roadway maintenance. Based on the geological conditions of Pingmei No.6 coal seam, a theoretical analysis, numerical simulation, and industrial experiments are carried out to calculate the reasonable width of chain pillars, analyze the lateral support stress distribution law near the gob side, investigate the relationship between the coal pillar stress distribution, roadway surrounding rock stress distribution, roadway surrounding rock deformation and the coal pillar width. The results indicate that 5 m wide coal pillars can ensure that the chain pillars are at a lower stress level and the deformation of roadway surrounding rock is in a more reasonable range. Industrial experiments show that when the chain pillar width is 5 m, the deformation of roadway surrounding rock can meet the requirements of working face safe production. The numerical results agreed well with field measurement and observations, and the industrial experiments results further validated the results of the numerical simulation.

A cooperative study of gate entry designs: Welbeck Colliery (UK) and Jim Walter Resources (USA)

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

Hendon, G.; Carr, F.; Lewis, A.

1995-11-01

Longwall developments in the UK have historically consisted of single entry gate roads. Adjacent developments were separated from existing pales by large barrier pillars (designed of sufficient width to get away from the longwall abutments of the previous panel) or by small barriers driven in the shadow, or de-stressed zone, of the previous panel. Some 2nd panel tailgates were also driven skin to skin leaving no coal barrier between the newly driven entry and the heavily supported existing gateroad. With the development and wide acceptance of fully bolted entries and the pressure to reduce production costs, alternatives to single entrymore » drivage, particularly yield pillar developments, were examined. Through the Rock Mechanics Branch of british Coal, a cooperative study was begun with Jim Walter Resources, Inc., USA, (JWR) to look at the yield pillar alternative in detail. This study was to determine the feasibility of utilizing yield pillars in the UK and to determine, through monitoring, the possibility of reducing stable pillar widths at JWR. The study has included extensive monitoring of the yield-stable-yield pillar system at JWR No. 7 Mine and an underground trial of a two entry yield pillar test area at Welbeck Colliery in the UK. This paper describes results from the JWR study and the subsequent results of the first advancing yield pillar development in the UK at Welbeck Colliery.« less

Dielectric anomaly and relaxation natures in a Zn-Cr pillar-layered metal-organic framework with cages and channels

NASA Astrophysics Data System (ADS)

Xue, Chen; Yao, Zhi-Yuan; Liu, Shao-Xian; Luo, Hong-Bin; Zou, Yang; Li, Li; Ren, Xiao-Ming

2017-06-01

A bimetallic metal-organic framework (MOF) with the formula [Zn3btc2{Cr3O(isonic)6(H2O)2(OH)}]·(DMF)15.5(H2O)8 (H3btc=1,3,5-benzenetricarboxylic acid; isonic=isonicotinicate) shows a pillar-layered structure. The monolayer consists of hexagon-like rings formed by the [Zn(isonic)2(btc)2] tetrahedral and the consecutive monolayers are pillared by trigonal-prismatic clusters of [Cr3O(isonic)6(H2O)2(OH)]through the remaining binding sites of the Zn2+ ions. DMF and water molecules are confined in the cages and channels. TGA indicates that the lattice DMF and water molecules begin to be released at temperatures above 363 K. Dielectric measurements were carried out in the range of 173-363 K and 1-107 Hz for three successive thermal cycles. The dielectric spectroscopy obtained in the first thermal cycle was different from that observed in the next two thermal cycles, while the dielectric spectra in the last two thermal cycles were almost identical. The dielectric nature of this MOF is discussed in detail for each thermal cycle. Since MOFs are unique host-guest systems in which the structure of the host framework is designable and the guests are exchangeable, it is no doubt those MOFs are materials with a variety of dielectric natures. This study gives a fresh impetus to achieve MOFs-based dielectric materials.

Using submarine lava pillars to record mid-ocean ridge eruption dynamics

USGS Publications Warehouse

Gregg, Tracy K.P.; Fornari, Daniel J.; Perfit, Michael R.; Ridley, W. Ian; Kurz, Mark D.

2000-01-01

Submarine lava pillars are hollow, glass-lined, basaltic cylinders that occur at the axis of the mid-ocean ridge, and within the summit calderas of some seamounts. Typically, pillars are ~1-20 m tall and 0.25-2.0 m in diameter, with subhorizontal to horizontal glassy selvages on their exterior walls. Lava pillars form gradually during a single eruption, and are composed of lava emplaced at the eruption onset as well as the last lava remaining after the lava pond has drained. On the deep sea floor, the surface of a basaltic lava flow quenches to glass within 1 s, thereby preserving information about eruption dynamics, as well as chemical and physical properties of lava within a single eruption. Investigation of different lava pillars collected from a single eruption allows us to distinguish surficial lava-pond or lava-lake geochemical processes from those operating in the magma chamber. Morphologic, major-element, petrographic and helium analyses were performed on portions of three lava pillars formed during the April 1991 eruption near 9°50'N at the axis of the East Pacific Rise. Modeling results indicate that the collected portions of pillars formed in ~2-5 h, suggesting a total eruption duration of ~8-20 h. These values are consistent with observed homogeneity in the glass helium concentrations and helium diffusion rates. Major-element compositions of most pillar glasses are homogeneous and identical to the 1991 flow, but slight chemical variations measured in the outermost portions of some pillars may reflect post-eruptive processes rather than those occurring in subaxial magma bodies. Because lava pillars are common at mid-ocean ridges (MORs), the concepts and techniques we present here may have important application to the study of MOR eruptions, thereby providing a basis for quantitative comparisons of volcanic eruptions in geographically and tectonically diverse settings. More research is needed to thoroughly test the hypotheses presented here. (C) 2000 Published by Elsevier Science B.V. All rights reserved.

Study of colloidal properties of natural and Al-pillared smectite and removal of copper ions from an aqueous solution.

PubMed

Sartor, Lucas Resmini; de Azevedo, Antonio Carlos; Andrade, Gabriel Ramatis Pugliese

2015-01-01

In this study, an Al-pillared smectite was synthesized and changes in its colloidal properties were investigated. The pillaring solution was prepared by mixing 0.4 mol L(-1) NaOH and 0.2 mol L(-1) AlCl3.6H2O solutions. Intercalated clays were heated to obtain the pillared clay, and X-ray diffractometry (XRD), X-ray fluorescence (XRF), Fourier transform infrared (FTIR) spectroscopy and N2 sorption/desorption isotherms analysis were done to characterize the changes in clay properties. Moreover, adsorption experiments were carried out in order to evaluate the capacity of the pillared clays to remove Cu2+ from an aqueous solution and to characterize the interaction between adsorbent and adsorbate. The results indicate that the natural clay has a basal spacing of 1.26 nm, whereas the pillared clays reached 1.78 nm (500°C) and 1.80 nm (350°C) after calcination. XRF analysis revealed an increase in the Al3+ in the pillared clay as compared to the natural clay. The surface area and pore volume (micro and mesoporous) were higher for the pillared clays. Experimental data from the adsorption experiment were fit to Langmuir and Freundlich and Temkin adsorption models, and the former one was the best fit (highest r2 value) for all the clays and lower standard deviation (Δg%) for the natural clay. On the other hand, the Temkin model exhibited Δg% value lower for the pillared clays. Thermodynamics parameters demonstrate that the Cu2+ adsorption process is spontaneous for all the clays, but with higher values for the pillared materials. In addition, application of the Dubinin-Radushkevich model revealed that the bond between the metal and the clay are weak, characterizing a physisorption.

Manufacturing of mushroom-shaped structures and its hydrophobic robustness analysis based on energy minimization approach

NASA Astrophysics Data System (ADS)

Wang, Li; Yang, Xiaonan; Wang, Quandai; Yang, Zhiqiang; Duan, Hui; Lu, Bingheng

2017-07-01

The construction of stable hydrophobic surfaces has increasingly gained attention owing to its wide range of potential applications. However, these surfaces may become wet and lose their slip effect owing to insufficient hydrophobic stability. Pillars with a mushroom-shaped tip are believed to enhance hydrophobicity stability. This work presents a facile method of manufacturing mushroom-shaped structures, where, compared with the previously used method, the modulation of the cap thickness, cap diameter, and stem height of the structures is more convenient. The effects of the development time on the cap diameter and overhanging angle are investigated and well-defined mushroom-shaped structures are demonstrated. The effect of the microstructure geometry on the contact state of a droplet is predicted by taking an energy minimization approach and is experimentally validated with nonvolatile ultraviolet-curable polymer with a low surface tension by inspecting the profiles of liquid-vapor interface deformation and tracking the trace of the receding contact line after exposure to ultraviolet light. Theoretical and experimental results show that, compared with regular pillar arrays having a vertical sidewall, the mushroom-like structures can effectively enhance hydrophobic stability. The proposed manufacturing method will be useful for fabricating robust hydrophobic surfaces in a cost-effective and convenient manner.

Cohesive detachment of an elastic pillar from a dissimilar substrate

NASA Astrophysics Data System (ADS)

Fleck, N. A.; Khaderi, S. N.; McMeeking, R. M.; Arzt, E.

The adhesion of micron-scale surfaces due to intermolecular interactions is a subject of intense interest spanning electronics, biomechanics and the application of soft materials to engineering devices. The degree of adhesion is sensitive to the diameter of micro-pillars in addition to the degree of elastic mismatch between pillar and substrate. Adhesion-strength-controlled detachment of an elastic circular cylinder from a dissimilar substrate is predicted using a Dugdale-type of analysis, with a cohesive zone of uniform tensile strength emanating from the interface corner. Detachment initiates when the opening of the cohesive zone attains a critical value, giving way to crack formation. When the cohesive zone size at crack initiation is small compared to the pillar diameter, the initiation of detachment can be expressed in terms of a critical value Hc of the corner stress intensity. The estimated pull-off force is somewhat sensitive to the choice of stick/slip boundary condition used on the cohesive zone, especially when the substrate material is much stiffer than the pillar material. The analysis can be used to predict the sensitivity of detachment force to the size of pillar and to the degree of elastic mismatch between pillar and substrate.

Boussinesq Modeling for Inlets, Harbors, and Structures (Bouss-2D)

DTIC Science & Technology

2015-10-30

a wide variety of coastal and ocean engineering and naval architecture problems, including: transformation of waves over small to medium spatial...and outputs, and GIS data used in modeling. Recent applications include: Pillar Point Harbor, Oyster Point Marina, CA; Mouth of Columbia River

The cuttlefish Sepia officinalis (Sepiidae, Cephalopoda) constructs cuttlebone from a liquid-crystal precursor

PubMed Central

Checa, Antonio G.; Cartwright, Julyan H. E.; Sánchez-Almazo, Isabel; Andrade, José P.; Ruiz-Raya, Francisco

2015-01-01

Cuttlebone, the sophisticated buoyancy device of cuttlefish, is made of extensive superposed chambers that have a complex internal arrangement of calcified pillars and organic membranes. It has not been clear how this structure is assembled. We find that the membranes result from a myriad of minor membranes initially filling the whole chamber, made of nanofibres evenly oriented within each membrane and slightly rotated with respect to those of adjacent membranes, producing a helical arrangement. We propose that the organism secretes a chitin–protein complex, which self-organizes layer-by-layer as a cholesteric liquid crystal, whereas the pillars are made by viscous fingering. The liquid crystallization mechanism permits us to homologize the elements of the cuttlebone with those of other coleoids and with the nacreous septa and the shells of nautiloids. These results challenge our view of this ultra-light natural material possessing desirable mechanical, structural and biological properties, suggesting that two self-organizing physical principles suffice to understand its formation. PMID:26086668

Corrugated metal surface with pillars for terahertz surface plasmon polariton waveguide components

NASA Astrophysics Data System (ADS)

Zhang, Ying; Xu, Yuehong; Tian, Chunxiu; Xu, Quan; Zhang, Xueqian; Li, Yanfeng; Zhang, Xixiang; Han, Jiaguang; Zhang, Weili

2018-01-01

In the terahertz regime, due to perfect conductivity of most metals, it is hard to realize a strong confinement of Surface plasmon polaritons (SPPs) although a propagation loss could be sufficiently low. We experimentally demonstrated a structure with periodic pillars arranged on a thin metal surface that supports bound modes of spoof SPPs at terahertz (THz) frequencies. By using scanning near-field THz microscopy, the electric field distribution above the metal surface within a distance of 130 μm was mapped. The results proved that this structure could guide spoof SPPs propagating along subwavelength waveguides, and at the same time reduce field expansion into free space. Further, for the development of integrated optical circuits, several components including straight waveguide, S-bend, Y-splitter and directional couplers were designed and characterized by the same method. We believe that the waveguide components proposed here will pave a new way for the development of flexible, wideband and compact photonic circuits operating at THz frequencies.

Eco-Friendly Magnetic Iron Oxide Pillared Montmorillonite for Advanced Catalytic Degradation of Dichlorophenol

EPA Science Inventory

Eco-friendly pillared montmorillonites, in which the pillars consist of iron oxide are expected to have interesting and unusual magnetic properties that are applicable for environmental decontamination. Completely “green” and effective composite was synthesized using mild reactio...

Radiographic classifications in Perthes disease

PubMed Central

Huhnstock, Stefan; Svenningsen, Svein; Merckoll, Else; Catterall, Anthony; Terjesen, Terje; Wiig, Ola

2017-01-01

Background and purpose Different radiographic classifications have been proposed for prediction of outcome in Perthes disease. We assessed whether the modified lateral pillar classification would provide more reliable interobserver agreement and prognostic value compared with the original lateral pillar classification and the Catterall classification. Patients and methods 42 patients (38 boys) with Perthes disease were included in the interobserver study. Their mean age at diagnosis was 6.5 (3–11) years. 5 observers classified the radiographs in 2 separate sessions according to the Catterall classification, the original and the modified lateral pillar classifications. Interobserver agreement was analysed using weighted kappa statistics. We assessed the associations between the classifications and femoral head sphericity at 5-year follow-up in 37 non-operatively treated patients in a crosstable analysis (Gamma statistics for ordinal variables, γ). Results The original lateral pillar and Catterall classifications showed moderate interobserver agreement (kappa 0.49 and 0.43, respectively) while the modified lateral pillar classification had fair agreement (kappa 0.40). The original lateral pillar classification was strongly associated with the 5-year radiographic outcome, with a mean γ correlation coefficient of 0.75 (95% CI: 0.61–0.95) among the 5 observers. The modified lateral pillar and Catterall classifications showed moderate associations (mean γ correlation coefficient 0.55 [95% CI: 0.38–0.66] and 0.64 [95% CI: 0.57–0.72], respectively). Interpretation The Catterall classification and the original lateral pillar classification had sufficient interobserver agreement and association to late radiographic outcome to be suitable for clinical use. Adding the borderline B/C group did not increase the interobserver agreement or prognostic value of the original lateral pillar classification. PMID:28613966

A Carbon Nanotube Pillar Array Ionizer for Miniature Ion Thruster Applications

DTIC Science & Technology

2008-12-01

interest in using argon as a propellant. The advantages of argon go beyond its low cost to include its inertness, which makes it safe to handle and...They can be formed either as single- walled structures (SWCNTs), as shown in Figure 5, or as multi-walled structures ( MWCNTs ), as shown in Figure 6...The structure in Figure 6 is known as a Russian Doll MWCNT due to its structure of concentric individual CNTs. There is another type of MWCNT known

Effects of bio-inspired microscale roughness on macroscale flow structures

NASA Astrophysics Data System (ADS)

Bocanegra Evans, Humberto; Hamed, Ali M.; Gorumlu, Serdar; Doosttalab, Ali; Aksak, Burak; Chamorro, Leonardo P.; Castillo, Luciano

2016-11-01

The interaction between rough surfaces and flows is a complex physical situation that produces rich flow phenomena. While random roughness typically increases drag, properly engineered roughness patterns may produce positive results, e.g. dimples in a golf ball. Here we present a set of PIV measurements in an index matched facility of the effect of a bio-inspired surface that consists of an array of mushroom-shaped micro-pillars. The experiments are carried out-under fully wetted conditions-in a flow with adverse pressure gradient, triggering flow separation. The introduction of the micro-pillars dramatically decreases the size of the recirculation bubble; the area with backflow is reduced by approximately 60%. This suggests a positive impact on the form drag generated by the fluid. Furthermore, a negligible effect is seen on the turbulence production terms. The micro-pillars affect the flow by generating low and high pressure perturbations at the interface between the bulk and roughness layer, in a fashion comparable to that of synthetic jets. The passive approach, however, facilitates the implementation of this coating. As the mechanism does not rely on surface hydrophobicity, it is well suited for underwater applications and its functionality should not degrade over time.

Five key pillars of an analytics center of excellence, which are required to manage populations and transform organizations into the next era of health care.

PubMed

Reichert, Jim; Furlong, Gerry

2014-01-01

Acute care facilities are experiencing fiscal challenges as noted by decreasing admissions and lower reimbursement creating an unsustainable fiscal environment as we move into the next era of health care. This situation necessitates a strategy to move away from acting solely on hunches and instinct to using analytics to become a truly data-driven organization that identifies opportunities within patient populations to improve the quality and efficiency of care across the continuum. A brief overview of knowledge management philosophies will be provided and how it is used to enable organizations to leverage data, information, and knowledge for operational transformation leading to improved outcomes. This article outlines the 5 key pillars of an Analytics Center of Excellence; governance, organizational structure, people, process, and technology, that are foundational to the development of this strategy. While culture is the most important factor to achieve organizational transformation and improved care delivery, it is the 5 pillars of the ACoE that will enable the culture shift necessary to become a truly data-driven organization and thus achieve transformation into the next era of health care.

Engineering fluid flow using sequenced microstructures

NASA Astrophysics Data System (ADS)

Amini, Hamed; Sollier, Elodie; Masaeli, Mahdokht; Xie, Yu; Ganapathysubramanian, Baskar; Stone, Howard A.; di Carlo, Dino

2013-05-01

Controlling the shape of fluid streams is important across scales: from industrial processing to control of biomolecular interactions. Previous approaches to control fluid streams have focused mainly on creating chaotic flows to enhance mixing. Here we develop an approach to apply order using sequences of fluid transformations rather than enhancing chaos. We investigate the inertial flow deformations around a library of single cylindrical pillars within a microfluidic channel and assemble these net fluid transformations to engineer fluid streams. As these transformations provide a deterministic mapping of fluid elements from upstream to downstream of a pillar, we can sequentially arrange pillars to apply the associated nested maps and, therefore, create complex fluid structures without additional numerical simulation. To show the range of capabilities, we present sequences that sculpt the cross-sectional shape of a stream into complex geometries, move and split a fluid stream, perform solution exchange and achieve particle separation. A general strategy to engineer fluid streams into a broad class of defined configurations in which the complexity of the nonlinear equations of fluid motion are abstracted from the user is a first step to programming streams of any desired shape, which would be useful for biological, chemical and materials automation.

Longwall gate road stability in a steeply pitching thick coal seam with a weak roof. Report of investigations/1995

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

Barron, L.R.; DeMarco, M.J.

1995-12-31

The U.S. Bureau of Mines conducted a ground pressure analysis of a wide abutment-type chain pillar in a two-entry gate road of a Western U.S. coal mine with an extremely weak immediate roof. This report discusses gate road layout and performance and secondary support effectiveness. The results of the pillar pressure study are compared to pillar loading predicted by a widely used pillar design method and to similar studies in other mines. A stability evaluation of the most recent longwall headgate, using the USBM Analysis of Longwall Pillar Stability (ALPS) indicates marginal stability in first-panel mining and instability in second-panelmore » mining. ALPS and the USBM Coal Mine Roof Rating (CMRR) system are used to evaluate tailgate-mining stability of the previous gate roads and to determine pillar and entry width and top coal thickness criteria for tailgate stability in future panels.« less

Improved synthesis and crystal structure of the flexible pillared layer porous coordination polymer: Ni(1,2-bis(4-pyridyl)ethylene)[Ni(CN) 4

DOE PAGES

Wong-Ng, W.; Culp, J. T.; Chen, Y. S.; ...

2013-01-01

This paper reports our synthesis of flexible coordination polymer, Ni(L)[Ni(CN) 4], (L = 1,2-bis(4-pyridyl)ethylene (nicknamed bpene)), and its structural characterization using synchrotron single crystal X-ray diffraction. The structure of the purplish crystals has been determined to be monoclinic, space group P2 1/m, a = 13.5941(12) Å, b = 14.3621(12) Å, c = 14.2561(12) Å, β = 96.141(2)°, V = 2767.4(4) Å 3, Z = 4, D c = 1.46 g cm -1. Ni(bpene)[Ni(CN) 4] assumes a pillared layer structure with layers defined by Ni[Ni(CN) 4] n nets and bpene ligands acting as pillars. With the present crystallization technique which involvesmore » the use of concentrated ammonium hydroxide solution and dimethyl sulfoxide (DMSO), disordered free bpene ligands and solvents of crystallization (DMSO and water molecules) occupy the pores, resulting in a formula of Ni(bpene)[Ni(CN) 4](1/2)bpene∙DMSO 2H 2O, or Ni 2N 7C 24H 25SO 3. Without the inclusion of free bpene ligands and solvent molecules, the free volume is approximately 61% of the total volume; this free volume fraction is reduced to 50% with the free ligands present. Pores without the free ligands were found to have a local diameter of 5.7 Å and a main aperture of 3.5 Å. Based on the successful crystal synthesis, we also devised a new bulk synthetic technique which yielded a polycrystalline material with a significantly improved CO 2 uptake as compared to the originally reported powder material. The improved synthetic technique yielded a polycrystalline material with 40% higher CO 2 uptake compared to the previously reported powder material. An estimated 14.4 molecules of CO 2 per unit cell was obtained.« less

Model-based design evaluation of a compact, high-efficiency neutron scatter camera

NASA Astrophysics Data System (ADS)

Weinfurther, Kyle; Mattingly, John; Brubaker, Erik; Steele, John

2018-03-01

This paper presents the model-based design and evaluation of an instrument that estimates incident neutron direction using the kinematics of neutron scattering by hydrogen-1 nuclei in an organic scintillator. The instrument design uses a single, nearly contiguous volume of organic scintillator that is internally subdivided only as necessary to create optically isolated pillars, i.e., long, narrow parallelepipeds of organic scintillator. Scintillation light emitted in a given pillar is confined to that pillar by a combination of total internal reflection and a specular reflector applied to the four sides of the pillar transverse to its long axis. The scintillation light is collected at each end of the pillar using a photodetector, e.g., a microchannel plate photomultiplier (MCP-PM) or a silicon photomultiplier (SiPM). In this optically segmented design, the (x , y) position of scintillation light emission (where the x and y coordinates are transverse to the long axis of the pillars) is estimated as the pillar's (x , y) position in the scintillator "block", and the z-position (the position along the pillar's long axis) is estimated from the amplitude and relative timing of the signals produced by the photodetectors at each end of the pillar. The neutron's incident direction and energy is estimated from the (x , y , z) -positions of two sequential neutron-proton scattering interactions in the scintillator block using elastic scatter kinematics. For proton recoils greater than 1 MeV, we show that the (x , y , z) -position of neutron-proton scattering can be estimated with < 1 cm root-mean-squared [RMS] error and the proton recoil energy can be estimated with < 50 keV RMS error by fitting the photodetectors' response time history to models of optical photon transport within the scintillator pillars. Finally, we evaluate several alternative designs of this proposed single-volume scatter camera made of pillars of plastic scintillator (SVSC-PiPS), studying the effect of pillar dimensions, scintillator material (EJ-204, EJ-232Q and stilbene), and photodetector (MCP-PM vs. SiPM) response vs. time. We demonstrate that the most precise estimates of incident neutron direction and energy can be obtained using a combination of scintillator material with high luminosity and a photodetector with a narrow impulse response. Specifically, we conclude that an SVSC-PiPS constructed using EJ-204 (a high luminosity plastic scintillator) and an MCP-PM will produce the most precise estimates of incident neutron direction and energy.

Navigating Complexities: An Integrative Approach to English Language Teacher Education

ERIC Educational Resources Information Center

Ryan, Phillip; Glodjo, Tyler; Hobbs, Bethany; Stargel, Victoria; Williams, Thad

2015-01-01

This article is an analysis of one undergraduate English language teacher education program's integrative theoretical framework that is structured around three pillars: interdisciplinarity, critical pedagogy, and teacher exploration. First, the authors survey the unique complexities of language teaching and learning. Then, they introduce this…

Size effect, critical resolved shear stress, stacking fault energy, and solid solution strengthening in the CrMnFeCoNi high-entropy alloy.

PubMed

Okamoto, Norihiko L; Fujimoto, Shu; Kambara, Yuki; Kawamura, Marino; Chen, Zhenghao M T; Matsunoshita, Hirotaka; Tanaka, Katsushi; Inui, Haruyuki; George, Easo P

2016-10-24

High-entropy alloys (HEAs) comprise a novel class of scientifically and technologically interesting materials. Among these, equatomic CrMnFeCoNi with the face-centered cubic (FCC) structure is noteworthy because its ductility and strength increase with decreasing temperature while maintaining outstanding fracture toughness at cryogenic temperatures. Here we report for the first time by single-crystal micropillar compression that its bulk room temperature critical resolved shear stress (CRSS) is ~33-43 MPa, ~10 times higher than that of pure nickel. CRSS depends on pillar size with an inverse power-law scaling exponent of -0.63 independent of orientation. Planar ½ < 110 > {111} dislocations dissociate into Shockley partials whose separations range from ~3.5-4.5 nm near the screw orientation to ~5-8 nm near the edge, yielding a stacking fault energy of 30 ± 5 mJ/m 2 . Dislocations are smoothly curved without any preferred line orientation indicating no significant anisotropy in mobilities of edge and screw segments. The shear-modulus-normalized CRSS of the HEA is not exceptionally high compared to those of certain concentrated binary FCC solid solutions. Its rough magnitude calculated using the Fleischer/Labusch models corresponds to that of a hypothetical binary with the elastic constants of our HEA, solute concentrations of 20-50 at.%, and atomic size misfit of ~4%.

Size effect, critical resolved shear stress, stacking fault energy, and solid solution strengthening in the CrMnFeCoNi high-entropy alloy

PubMed Central

Okamoto, Norihiko L.; Fujimoto, Shu; Kambara, Yuki; Kawamura, Marino; Chen, Zhenghao M. T.; Matsunoshita, Hirotaka; Tanaka, Katsushi; Inui, Haruyuki; George, Easo P.

2016-01-01

High-entropy alloys (HEAs) comprise a novel class of scientifically and technologically interesting materials. Among these, equatomic CrMnFeCoNi with the face-centered cubic (FCC) structure is noteworthy because its ductility and strength increase with decreasing temperature while maintaining outstanding fracture toughness at cryogenic temperatures. Here we report for the first time by single-crystal micropillar compression that its bulk room temperature critical resolved shear stress (CRSS) is ~33–43 MPa, ~10 times higher than that of pure nickel. CRSS depends on pillar size with an inverse power-law scaling exponent of –0.63 independent of orientation. Planar ½ < 110 > {111} dislocations dissociate into Shockley partials whose separations range from ~3.5–4.5 nm near the screw orientation to ~5–8 nm near the edge, yielding a stacking fault energy of 30 ± 5 mJ/m2. Dislocations are smoothly curved without any preferred line orientation indicating no significant anisotropy in mobilities of edge and screw segments. The shear-modulus-normalized CRSS of the HEA is not exceptionally high compared to those of certain concentrated binary FCC solid solutions. Its rough magnitude calculated using the Fleischer/Labusch models corresponds to that of a hypothetical binary with the elastic constants of our HEA, solute concentrations of 20–50 at.%, and atomic size misfit of ~4%. PMID:27775026

On the origin of electrical conductivity in the bio-electronic material melanin

NASA Astrophysics Data System (ADS)

Bernardus Mostert, A.; Powell, Ben J.; Gentle, Ian R.; Meredith, Paul

2012-02-01

The skin pigment melanin is one of a few bio-macromolecules that display electrical and photo-conductivity in the solid-state. A model for melanin charge transport based on amorphous semiconductivity has been widely accepted for 40 years. In this letter, we show that a central pillar in support of this hypothesis, namely experimental agreement with a hydrated dielectric model, is an artefact related to measurement geometry and non-equilibrium behaviour. Our results cast significant doubt on the validity of the amorphous semiconductor model and are a reminder of the difficulties of electrical measurements on low conductivity, disordered organic materials.

Improvement of fluorescence intensity of nitrogen vacancy centers in self-formed diamond microstructures

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

Furuyama, S.; Yaita, J.; Kondo, M.

2015-10-19

We present umbrella-shaped diamond microstructures with metal mirrors at the bottom in order to improve the amount of collected photons from nitrogen vacancy centers. The metal mirrors at the bottom are self-aligned to the umbrella-shaped diamond microstructures which are selectively grown through holes created on a metal mask. By the finite-difference time-domain simulations, we found that the umbrella-shaped microstructures, which have an effect similar to solid immersion lens, could collect photons more efficiently than bulk or pillar-shaped microstructures. Improvement of the fluorescence intensity by factors of from 3 to 5 is shown experimentally.

33 CFR 80.1140 - Pillar Point Harbor, CA.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Pillar Point Harbor, CA. 80.1140 Section 80.1140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1140 Pillar Point Harbor, CA. A line drawn from...

33 CFR 80.1140 - Pillar Point Harbor, CA.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Pillar Point Harbor, CA. 80.1140 Section 80.1140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1140 Pillar Point Harbor, CA. A line drawn from...

33 CFR 80.1140 - Pillar Point Harbor, CA.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Pillar Point Harbor, CA. 80.1140 Section 80.1140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1140 Pillar Point Harbor, CA. A line drawn from...

33 CFR 80.1140 - Pillar Point Harbor, CA.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Pillar Point Harbor, CA. 80.1140 Section 80.1140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1140 Pillar Point Harbor, CA. A line drawn from...

33 CFR 80.1140 - Pillar Point Harbor, CA.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Pillar Point Harbor, CA. 80.1140 Section 80.1140 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY INTERNATIONAL NAVIGATION RULES COLREGS DEMARCATION LINES Pacific Coast § 80.1140 Pillar Point Harbor, CA. A line drawn from...

Size and Crystallographic Orientation Effects on the Mechanical Behavior of 4H-SiC Micro-/nano-pillars

NASA Astrophysics Data System (ADS)

Guo, Xiaolei; Guo, Qiang; Li, Zhiqiang; Fan, Genlian; Xiong, Ding-Bang; Su, Yishi; Zhang, Jie; Tan, Zhanqiu; Guo, Cuiping; Zhang, Di

2018-02-01

Single crystalline 4H-SiC micro-/nano-pillars of various sizes and different crystallographic orientations were fabricated and tested by uniaxial compression. The pillars with zero shear stress resolved on the basal slip system were found to fracture in a brittle manner without showing significant size dependence, while the pillars with non-zero resolved shear stress showed a "smaller is stronger" behavior and a jerky plastic flow. These observations were interpreted by homogeneous dislocation nucleation and dislocation glide on the basal plane.

Coal rib response during bench mining: A case study

PubMed Central

Sears, Morgan M.; Rusnak, John; Van Dyke, Mark; Rashed, Gamal; Mohamed, Khaled; Sloan, Michael

2018-01-01

In 2016, room-and-pillar mining provided nearly 40% of underground coal production in the United States. Over the past decade, rib falls have resulted in 12 fatalities, representing 28% of the ground fall fatalities in U.S. underground coal mines. Nine of these 12 fatalities (75%) have occurred in room-and-pillar mines. The objective of this research is to study the geomechanics of bench room-and-pillar mining and the associated response of high pillar ribs at overburden depths greater than 300 m. This paper provides a definition of the bench technique, the pillar response due to loading, observational data for a case history, a calibrated numerical model of the observed rib response, and application of this calibrated model to a second site. PMID:29862125

Atomic Resolution Structural and Chemical Imaging Revealing the Sequential Migration of Ni, Co, and Mn upon the Battery Cycling of Layered Cathode

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

Yan, Pengfei; Zheng, Jianming; Zhang, Ji-Guang

Layered lithium transition metal oxides (LTMO) are promising candidate cathode materials for next generation high energy density lithium ion battery. The challenge for using this category of cathode is the capacity and voltage fading, which is believed to be associated with the layered structure disordering, a process that is initiated from the surface or solid-electrolyte interface and facilitated by transition metal (TM) reduction and oxygen vacancy formation. However, the atomic level dynamic mechanism of such a layered structure disordering is still not fully clear. In this work, utilizing atomic resolution electron energy loss spectroscopy (EELS), we map, for the firstmore » time at atomic scale, the spatial evolution of Ni, Co and Mn in a cycled LiNi1/3M1/3Co1/3O2 layered cathode. In combination with atomic level structural imaging, we discovered the direct correlation of TM ions migration behavior with lattice disordering, featuring the residing of TM ions in the tetrahedral site and a sequential migration of Ni, Co, and Mn upon the increased lattice disordering of the layered structure. This work highlights that Ni ions, though acting as the dominant redox species in many LTMO, are labile to migrate to cause lattice disordering upon battery cycling; while the Mn ions are more stable as compared with Ni and Co and can act as pillar to stabilize layered structure. Direct visualization of the behavior of TM ions during the battery cycling provides insight for designing of cathode with structural stability and correspondingly a superior performance.« less

The synthesis and application of pillared clays prepared from charge reduced montmorillonite

NASA Astrophysics Data System (ADS)

Engwall, Erik Edwin

The synthesis of pillared interlayered clays (PILCs) makes use of the cation exchange capacity (CEC) of clay minerals to prop their structures open with large hydroxy-metal cations. Homo-ionic Ca-Montmorillonite with a CEC of 83.9 meq/100 g has been partially exchanged with varied amounts of Li+ and heated to 200°C for 24 hours. These have been used to produce Zr and Al PILCs making use of ethanol/water synthesis solutions to overcome the hydrophobic nature of the clay. For the Zr-PILC system, the d(001) spacings determined by x-ray diffraction (XRD) were relatively constant at 19.0--20.1 A with respect to changing the unpillared CEC. The Zr-PILCs had type I isotherms for argon at 87 K and for benzene, p-xylene and 1,3,5-trimethylbenzene adsorption at 30°C. Several Al-PILC synthesis procedures were evaluated and all produced materials whose adsorption capacity decreased with decreasing unpillared CEC. This reduction in adsorption capacity with unpillared CEC could be partially overcome by the combined use of ethanol/water pillaring solutions with ethanol/water washing. Previously unreported d(001) values in the range of 26.8 to 29.8 A were observed in Al-PILCs and were often bimodal with the expected values of about 18 A. These larger d(001) values were most prevalent at lower CEC values, if pillaring conditions favored the formation of polymeric species other than the Keggin cation. A new micropore size distribution model was developed to better understand PILC pore structure. The new model was compared to the Horvath and Kawazoe (1983) model (HK) and the Cheng and Yang (1994) model (CY) using argon adsorption at 87 K on Zr and Al-PILCs. The interlayer spacings determined by XRD for the test PILCs were 9.5 and 8.5 A for Zr and Al-PILCs respectively. Pore sizes predicted by the new model were 7.5 and 7.3 A for Zr and Al-PILCs respectively. The new model consistently predicts values that are closer to the interlayer spacing than either the HK or CY models. The new model showed little change in pore size with changes in unpillared CEC for the Zr-PILC system. These results indicate that the limiting dimension in the PILC pore system is the inter-layer spacing and not the inter-pillar spacing. (Abstract shortened by UMI.)

Biomechanical Characteristics of an Integrated Lumbar Interbody Fusion Device

PubMed Central

Voronov, Leonard I.; Vastardis, Georgios; Zelenakova, Julia; Carandang, Gerard; Havey, Robert M.; Waldorff, Erik I.; Zindrick, Michael R.

2014-01-01

Introduction We hypothesized that an Integrated Lumbar Interbody Fusion Device (PILLAR SA, Orthofix, Lewisville, TX) will function biomechanically similar to a traditional anterior interbody spacer (PILLAR AL, Orthofix, Lewisville, TX) plus posterior instrumentation (FIREBIRD, Orthofix, Lewisville, TX). Purpose of this study was to determine if an Integrated Interbody Fusion Device (PILLAR SA) can stabilize single motion segments as well as an anterior interbody spacer (PILLAR AL) + pedicle screw construct (FIREBIRD). Methods Eight cadaveric lumbar spines (age: 43.9±4.3 years) were used. Each specimen's range of motion was tested in flexion-extension (FE), lateral bending (LB), and axial rotation (AR) under intact condition, after L4-L5 PILLAR SA with intervertebral screws and after L4-L5 360° fusion (PILLAR AL + Pedicle Screws and rods (FIREBIRD). Each specimen was tested in flexion (8Nm) and extension (6Nm) without preload (0 N) and under 400N of preload, in lateral bending (±6 Nm) and axial rotation (±5 Nm) without preload. Results Integrated fusion using the PILLAR SA device demonstrated statistically significant reductions in range of motion of the L4-L5 motion segment as compared to the intact condition for each test direction. PILLAR SA reduced ROM from 8.9±1.9 to 2.9±1.1° in FE with 400N follower preload (67.4%), 8.0±1.7 to 2.5±1.1° in LB, and 2.2±1.2 to 0.7±0.3° in AR. A comparison between the PILLAR SA integrated fusion device versus 360° fusion construct with spacer and bilateral pedicle screws was statistically significant in FE and LB. The 360° fusion yielded motion of 1.0±0.5° in FE, 1.0±0.8° in LB (p0.05). Conclusions The PILLAR SA resulted in motions of less than 3° in all modes of motion and was not as motion restricting as the traditional 360° using bilateral pedicle screws. The residual segmental motions compare very favorably with published biomechanical studies of other interbody integrated fusion devices. PMID:25694931

Novel special energy for environmental friendly excavation

NASA Astrophysics Data System (ADS)

Xie, Xinghua; Feng, Yuqing; Zhou, Huisheng

2018-03-01

This paper introduces a new high-energy combustion rock-breaking pillar which can be used for cutting, breaking rock, vibrating vibration, no throwing, no toxic gas generation, no dust, special charge structure is easier to block. Non-metallic raw materials, are easy to produce with low cost, good economic returns, and security.

Environmental Pride: Jain Shrine

ERIC Educational Resources Information Center

School Arts: The Art Education Magazine for Teachers, 2004

2004-01-01

The Cincinnati Art Museum's Jain shrine is an elaborate structure that allows Jains to contemplate a life of peace, discipline, and freedom from earthly desires. This shrine, an elaborately carved canopy (typically used by royalty) with two freestanding support pillars, was made during an important growth period that saw the building of numerous…

Relations between Eastern Four Pillars Theory and Western Measures of Personality Traits

PubMed Central

Jung, Seung Ah

2015-01-01

Purpose The present study investigated the validity of personality classification using four pillars theory, a tradition in China and northeastern Asia. Materials and Methods Four pillars analyses were performed for 148 adults on the basis of their birth year, month, day, and hour. Participants completed two personality tests, the Korean version of Temperament and Character Inventory-Revised-Short Version (TCI) and the Korean Inventory of Interpersonal Problems; scores were correlated with four pillars classification elements. Mean difference tests (e.g., t-test, ANOVA) were compared with groups classified by four pillars index. Results There were no significant correlations between personality scale scores and total yin/yang number (i.e., the 8 heavenly or earthly stems), and no significant between-groups results for classifications by yin/yang day stem and the five elements. There were significant but weak (r=0.18-0.29) correlations between the five elements and personality scale scores. For the six gods and personality scales, there were significant but weak (r=0.18-0.25) correlations. Features predicted by four pillars theory were most consistent when participants were grouped according to the yin/yang of the day stem and dominance of yin/yang numbers in the eight heavenly or earthly stems. Conclusion Although the major criteria of four pillars theory were not independently correlated with personality scale scores, correlations emerged when participants were grouped according to the composite yin/yang variable. Our results suggest the utility of four pillars theory (beyond fortune telling or astrology) for classifying personality traits and making behavioral predictions. PMID:25837175

Characterization of spiral ganglion neurons cultured on silicon micro-pillar substrates for new auditory neuro-electronic interfaces.

PubMed

Mattotti, M; Micholt, L; Braeken, D; Kovačić, D

2015-04-01

One of the strategies to improve cochlear implant technology is to increase the number of electrodes in the neuro-electronic interface. The objective was to characterize in vitro cultures of spiral ganglion neurons (SGN) cultured on surfaces of novel silicon micro-pillar substrates (MPS). SGN from P5 rat pups were cultured on MPS with different micro-pillar widths (1-5.6 μm) and spacings (0.6-15 μm) and were compared with control SGN cultures on glass coverslips by immunocytochemistry and scanning electron microscopy (SEM). Overall, MPS support SGN growth equally well as the control glass surfaces. Micro-pillars of a particular size-range (1.2-2.4 μm) were optimal in promoting SGN presence, neurite growth and alignment. On this specific micro-pillar size, more SGN were present, and neurites were longer and more aligned. SEM pictures highlight how cells on micro-pillars with smaller spacings grow directly on top of pillars, while at wider spacings (from 3.2 to 15 μm) they grow on the bottom of the surface, losing contact guidance. Further, we found that MPS encourage more monopolar and bipolar SGN morphologies compared to the control condition. Finally, MPS induce longest neurite growth with minimal interaction of S100+ glial cells. These results indicate that silicon micro-pillar substrates create a permissive environment for the growth of primary auditory neurons promoting neurite sprouting and are a promising technology for future high-density three-dimensional CMOS-based auditory neuro-electronic interfaces.

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.

Hierarchical structures of carbon nanotubes and arrays of chromium-capped silicon nanopillars: formation and electrical properties.

PubMed

Koch, Stefan; Joshi, Ravi K; Noyong, Michael; Timper, Jan; Schneider, Jörg J; Simon, Ulrich

2012-09-10

The formation of stochastically oriented carbon-nanotube networks on top of an array of free-standing chromium-capped silicon nanopillars is reported. The combination of nanosphere lithography and chemical vapor deposition enables the construction of nanostructures that exhibit a hierarchical sequence of structural sizes. Metallic chromium serves as an etching mask for Si-pillar formation and as a nucleation site for the formation of carbon nanotubes through the chemical vapor deposition of ethene, ethanol, and methane, respectively, thereby bridging individual pillars from top to top. Iron and cobalt were applied onto the chromium caps as catalysts for CNT growth and the influence of different carbon sources and different gas-flow rates were investigated. The carbon nanotubes were structurally characterized and their DC electrical properties were studied by in situ local- and ex situ macroscopic measurements, both of which reveal their semiconductor properties. This process demonstrates how carbon nanotubes can be integrated into Si-based semiconductors and, thus, this process may be used to form high-surface-area sensors or new porous catalyst supports with enhanced gas-permeation properties. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Development of sequence-tagged site markers linked to the pillar growth type in peach (Prunus persica)

USDA-ARS?s Scientific Manuscript database

In peach [Prunus persica (L.) Batsch], trees showing columnar [also termed pillar or broomy] growth habit are of interest for high density production systems. While the selection of the columnar homozygote (pillar) phenotype (brbr) can be carried out prior to field planting, the intermediate hetero...

Pillar[n]arene-based supramolecular organic frameworks with high hydrocarbon storage and selectivity

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

Tan, Li-Li; Zhu, Youlong; Long, Hai

2017-01-01

We report the high hydrocarbon storage capacity and adsorption selectivity of two low-density pillar[n]arene-based SOFs. Our study would open new perspectives in the development of pillar[n]arene-based SOFs and study of their great potential in gas-storage and gas-separation applications.

The Sloan-C Pillars: Towards a Balanced Approach to Measuring Organizational Learning

ERIC Educational Resources Information Center

Yeo, Kee Meng; Mayadas, A. Frank

2010-01-01

The Sloan Pillars have set the standard for university-wide online learning program assessment for more than a dozen years. In this paper, the authors propose the extension of the Pillars to corporate e-learning, offering an alternative to traditional enterprise learning assessments. Claiming that conventional methods stress individual courses or…

Tribological behavior of micro/nano-patterned surfaces in contact with AFM colloidal probe

NASA Astrophysics Data System (ADS)

Zhang, Xiaoliang; Wang, Xiu; Kong, Wen; Yi, Gewen; Jia, Junhong

2011-10-01

In effort to investigate the influence of the micro/nano-patterning or surface texturing on the nanotribological properties of patterned surfaces, the patterned polydimethylsiloxane (PDMS) surfaces with pillars were fabricated by replica molding technique. The surface morphologies of patterned PDMS surfaces with varying pillar sizes and spacing between pillars were characterized by atomic force microscope (AFM) and scanning electron microscope (SEM). The AFM/FFM was used to acquire the friction force images of micro/nano-patterned surfaces using a colloidal probe. A difference in friction force produced a contrast on the friction force images when the colloidal probe slid over different regions of the patterned polymer surfaces. The average friction force of patterned surface was related to the spacing between the pillars and their size. It decreased with the decreasing of spacing between the pillars and the increasing of pillar size. A reduction in friction force was attributed to the reduced area of contact between patterned surface and colloidal probe. Additionally, the average friction force increased with increasing applied load and sliding velocity.

Removal of Cs+ from water and soil by ammonium-pillared montmorillonite/Fe3O4 composite.

PubMed

Zheng, Xianming; Dou, Junfeng; Yuan, Jing; Qin, Wei; Hong, Xiaoxi; Ding, Aizhong

2017-06-01

To remove cesium ions from water and soil, a novel adsorbent was synthesized by following a one-step co-precipitation method and using non-toxic raw materials. By combining ammonium-pillared montmorillonite (MMT) and magnetic nanoparticles (Fe 3 O 4 ), an MMT/Fe 3 O 4 composite was prepared and characterized. The adsorbent exhibited high selectivity of Cs + and could be rapidly separated from the mixed solution under an external magnetic field. Above all, the adsorbent had high removal efficiency in cesium-contaminated samples (water and soil) and also showed good recycling performance, indicating that the MMT/Fe 3 O 4 composite could be widely applied to the remediation of cesium-contaminated environments. It was observed that the pH, solid/liquid ratio and initial concentration affected adsorption capacity. In the presence of coexisting ions, the adsorption capacity decreased in the order of Ca 2+ >Mg 2+ >K + >Na + , which is consistent with our theoretical prediction. The adsorption behavior of this new adsorbent could be expressed by the pseudo-second-order model and Freundlich isotherm. In addition, the adsorption mechanism of Cs + was NH 4 + ion exchange and surface hydroxyl group coordination, with the former being more predominant. Copyright © 2016. Published by Elsevier B.V.

Fiber-coupled pillar array as a highly pure and stable single-photon source

NASA Astrophysics Data System (ADS)

Odashima, S.; Sasakura, H.; Nakajima, H.; Kumano, H.

2017-12-01

A highly pure and stable single-photon source is prepared that comprises a well-designed pillar array, in which each pillar contains only a few InAs quantum dots. A nano-pillar in this array is in direct contact with a fiber end surface and cooled in a liquid-He bath. Auto-correlation measurements show that this source provides an average g(2)(0) value of 0.0174 in the measured excitation-power range. This photon source and fiber coupling are quite rigid against external disturbances such as cooling-heating cycles and vibration, with long-term stability.

H II Region G46.5-0.2: The Interplay between Ionizing Radiation, Molecular Gas, and Star Formation

NASA Astrophysics Data System (ADS)

Paron, S.; Ortega, M. E.; Dubner, G.; Yuan, Jing-Hua; Petriella, A.; Giacani, E.; Zeng Li, Jin; Wu, Yuefang; Liu, Hongli; Huang, Ya Fang; Zhang, Si-Ju

2015-06-01

H ii regions are particularly interesting because they can generate dense layers of gas and dust, elongated columns or pillars of gas pointing toward the ionizing sources, and cometary globules of dense gas where triggered star formation can occur. Understanding the interplay between the ionizing radiation and the dense surrounding gas is very important to explain the origin of these peculiar structures, and hence to characterize triggered star formation. G46.5-0.2 (G46), a poorly studied galactic H ii region located at about 4 kpc, is an excellent target for performing this kind of study. Using public molecular data extracted from the Galactic Ring Survey (13CO J = 1-0) and from the James Clerk Maxwell Telescope data archive (12CO, 13CO, C18O J = 3-2, HCO+, and HCN J = 4-3), and infrared data from the GLIMPSE and MIPSGAL surveys, we perform a complete study of G46, its molecular environment, and the young stellar objects (YSOs) placed around it. We found that G46, probably excited by an O7V star, is located close to the edge of the GRSMC G046.34-00.21 molecular cloud. It presents a horse-shoe morphology opening in the direction of the cloud. We observed a filamentary structure in the molecular gas likely related to G46 and not considerable molecular emission toward its open border. We found that about 10‧ to the southwest of G46 there are some pillar-like features, shining at 8 μm and pointing toward the H ii region open border. We propose that the pillar-like features were carved and sculpted by the ionizing flux from G46. We found several YSOs likely embedded in the molecular cloud grouped in two main concentrations: one, closer to the G46 open border consisting of Class II type sources, and another mostly composed of Class I type YSOs located just ahead of the pillar-like features, strongly suggesting an age gradient in the YSO distribution.

H ii REGION G46.5-0.2: THE INTERPLAY BETWEEN IONIZING RADIATION, MOLECULAR GAS, AND STAR FORMATION

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

Paron, S.; Ortega, M. E.; Dubner, G.

2015-06-15

H ii regions are particularly interesting because they can generate dense layers of gas and dust, elongated columns or pillars of gas pointing toward the ionizing sources, and cometary globules of dense gas where triggered star formation can occur. Understanding the interplay between the ionizing radiation and the dense surrounding gas is very important to explain the origin of these peculiar structures, and hence to characterize triggered star formation. G46.5-0.2 (G46), a poorly studied galactic H ii region located at about 4 kpc, is an excellent target for performing this kind of study. Using public molecular data extracted from themore » Galactic Ring Survey ({sup 13}CO J = 1–0) and from the James Clerk Maxwell Telescope data archive ({sup 12}CO, {sup 13}CO, C{sup 18}O J = 3–2, HCO{sup +}, and HCN J = 4–3), and infrared data from the GLIMPSE and MIPSGAL surveys, we perform a complete study of G46, its molecular environment, and the young stellar objects (YSOs) placed around it. We found that G46, probably excited by an O7V star, is located close to the edge of the GRSMC G046.34-00.21 molecular cloud. It presents a horse-shoe morphology opening in the direction of the cloud. We observed a filamentary structure in the molecular gas likely related to G46 and not considerable molecular emission toward its open border. We found that about 10′ to the southwest of G46 there are some pillar-like features, shining at 8 μm and pointing toward the H ii region open border. We propose that the pillar-like features were carved and sculpted by the ionizing flux from G46. We found several YSOs likely embedded in the molecular cloud grouped in two main concentrations: one, closer to the G46 open border consisting of Class II type sources, and another mostly composed of Class I type YSOs located just ahead of the pillar-like features, strongly suggesting an age gradient in the YSO distribution.« less

Waveguide Photonic Choke Joint with Wide Out-of-Band Rejection

NASA Technical Reports Server (NTRS)

U-yen, Kongpop; Wollack, Edward J.

2015-01-01

A photonic choke joint structure with a wide-stop-band is proposed for use as a waveguide flange interface. The structure consists of arrays of square metal pillars arranged in a periodic pattern to suppress the dominant-mode wave propagation in parallel-plate waveguide over a wide frequency bandwidth. The measurement results at microwave frequencies confirm that the structure can provide broadband suppression of more than 56dB over 6.25 times its operating frequency. Applications at millimeter wavelength are discussed.

Waveguide Photonic Choke Joint with Wide Out-of-Band Rejection

NASA Technical Reports Server (NTRS)

U-yen, Kongpop; Wollack, Edward J.

2015-01-01

A photonic choke joint structure with a wide- stop-band is proposed for use as a waveguide flange interface. The structure consists of arrays of square metal pillars arranged in a periodic pattern to suppress the dominant-mode wave propagation in parallel-plate waveguide over a wide frequency bandwidth. The measurement results at microwave frequencies confirm the structure can provide broadband suppression, more than 56 dB over 6.25 times its operating frequency. Applications at millimeter wavelength are discussed.

High Resolution Quantification of Cellular Forces for Rigidity Sensing

NASA Astrophysics Data System (ADS)

Liu, Shuaimin

This thesis describes a comprehensive study of understanding the mechanism of rigidity sensing by quantitative analysis using submicron pillar array substrates. From mechanobiology perspective, we explore and study molecular pathways involved in rigidity and force sensing at cell-matrix adhesions with regard to cancer, regeneration, and development by quantification methods. In Chapter 2 and 3, we developed fabrication and imaging techniques to enhance the performance of a submicron pillar device in terms of spatial and temporal measurement ability, and we discovered a correlation of rigidity sensing forces and corresponding proteins involved in the early rigidity sensing events. In Chapter 2, we introduced optical effect arising from submicron structure imaging, and we described a technique to identify the correct focal plane of pillar tip by fabricating a substrate with designed-offset pillars. From calibration result, we identified the correct focal plane that was previously overlooked, and verified our findings by other imaging techniques. In Chapter 3, we described several techniques to selectively functionalize elastomeric pillars top and compared these techniques in terms of purposes and fabrication complexity. Techniques introduced in this chapter included direct labeling, such as stamping of fluorescent substances (organic dye, nano-diamond, q-dot) to pillars top, as well as indirect labeling that selectively modify the surface of molds with either metal or fluorescent substances. In Chapter 4, we examined the characteristics of local contractility forces and identified the components formed a sarcomere like contractile unit (CU) that cells use to sense rigidity. CUs were found to be assembled at cell edge, contain myosin II, alpha-actinin, tropomodulin and tropomyosin (Tm), and resemble sarcomeres in size (˜2 mum) and function. Then we performed quantitative analysis of CUs to evaluate rigidity sensing activity over ˜8 hours time course and found that density of CUs decrease with time after spreading on stiff substrate. However addition of EGF dramatically increased local contraction activity such that about 30% of the total contractility was in the contraction units. This stimulatory effect was only observed on stiff substrate not on soft. Moreover, we find that in the early interactions of cells with rigid substrates that EGFR activity is needed for normal spreading and the assembly of local contraction units in media lacking serum and any soluble EGF. In Chapter 5, we performed high temporal- and spatial-resolution tracking of contractile forces exerted by cells on sub-micron elastomeric pillars. We found that actomyosin-based sarcomere-like CUs simultaneously moved opposing pillars in net steps of ˜2.5 nm, independent of rigidity. What correlated with rigidity was the number of steps taken to reach a force level that activated recruitment of alpha-actinin to the CUs. When we removed actomyosin restriction by depleting tropomyosin 2.1, we observed larger steps and higher forces that resulted in aberrant rigidity sensing and growth of non-transformed cells on soft matrices. Thus, we conclude that tropomyosin 2.1 acts as a suppressor of growth on soft matrices by supporting proper rigidity sensing.

Tuning the formations of metal-1,3,5-benzenetricarboxylate frameworks via the assistance of amino acids

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

Lei, Xiao-Ping; Lian, Ting-Ting; Chen, Shu-Mei, E-mail: csm@fzu.edu.cn

Seven new metal-1,3,5-benzenetricarboxylate coordination polymers have been synthesized by modification of auxiliary components during the assembly reactions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by XRD and TGA. Interestingly, they show fascinating topological structures. Compounds 1 and 2 possess the undulating layer structure with 3-connected hcb network and (3,6)-connected kgd network. Compound 3 possesses three-dimensional (3D) pillared-layer structure with 3-connected 2-fold interpenetrating srs net. Compound 4 also has the 3D 2-fold interpenetrating pillared-layer structure; however, it has (3,5)-connected hms topology because the Cd(II) center is 5-connected. Compound 5 possess 3D structure through hydrogen bondingmore » interactions between ladder-like layers. Compounds 6 and 7 have the similar 3D frameworks with 4-connected umc net and (3,7)-connected (3.4.5)(3{sup 2}.4{sup 6}.5{sup 5}.6{sup 8}) topology, respectively. The photoluminescent properties of compounds 2–7 were also investigated. - Graphical abstract: Presented here are seven new metal-1,3,5-benzenetricarboxylate coordination polymers with diverse structures from 2D layers to 3D open frameworks. The synthesis and structural diversity of these compounds are determined by the additional amino acids as unusual buffering agents. - Highlights: • Structural diversity of metal-1,3,5-benzenetricarboxylate frameworks. • Tuning structural topologies of MOFs via the assistance of amino acids. • Amino acids as unusual buffering agents for the synthesis of MOFs.« less

30 CFR 75.207 - Pillar recovery.

Code of Federal Regulations, 2011 CFR

2011-07-01

... be left in place. (b) Before mining is started in a pillar split or lift— (1) At least two rows of... leading into the split or lift. (c) Before mining is started on a final stump— (1) At least 2 rows of... shall be installed between the lift to be started and the area where pillars have been extracted. These...

30 CFR 75.207 - Pillar recovery.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be left in place. (b) Before mining is started in a pillar split or lift— (1) At least two rows of... leading into the split or lift. (c) Before mining is started on a final stump— (1) At least 2 rows of... shall be installed between the lift to be started and the area where pillars have been extracted. These...

Ten Pillars of a Good Childhood: A Finnish Perspective

ERIC Educational Resources Information Center

Pulkkinen, Lea

2012-01-01

The organizers of the Decade for Childhood have formulated Ten Pillars of a Good Childhood as basic requirements for an optimal childhood. The pillars can be used to analyze the quality of childhood in homes and nations, and to guide policies and practices related to the experience of childhood. In this article, the author shall illustrate, pillar…

43 CFR 3931.100 - Boundary pillars and buffer zones.

Code of Federal Regulations, 2013 CFR

2013-10-01

... otherwise specified in writing by the BLM. Boundary and other main pillars may be mined only with the BLM's prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from the..., mine out and remove all available oil shale in such boundary pillar, both in the lands covered by the...

43 CFR 3931.100 - Boundary pillars and buffer zones.

Code of Federal Regulations, 2012 CFR

2012-10-01

... otherwise specified in writing by the BLM. Boundary and other main pillars may be mined only with the BLM's prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from the..., mine out and remove all available oil shale in such boundary pillar, both in the lands covered by the...

43 CFR 3931.100 - Boundary pillars and buffer zones.

Code of Federal Regulations, 2014 CFR

2014-10-01

... otherwise specified in writing by the BLM. Boundary and other main pillars may be mined only with the BLM's prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from the..., mine out and remove all available oil shale in such boundary pillar, both in the lands covered by the...

43 CFR 3931.100 - Boundary pillars and buffer zones.

Code of Federal Regulations, 2011 CFR

2011-10-01

... otherwise specified in writing by the BLM. Boundary and other main pillars may be mined only with the BLM's prior written consent or on the BLM's order. For in-situ operations, a 50-foot buffer zone from the..., mine out and remove all available oil shale in such boundary pillar, both in the lands covered by the...

High-Resolution Printing of 3D Structures Using an Electrohydrodynamic Inkjet with Multiple Functional Inks.

PubMed

An, Byeong Wan; Kim, Kukjoo; Lee, Heejoo; Kim, So-Yun; Shim, Yulhui; Lee, Dae-Young; Song, Jun Yeob; Park, Jang-Ung

2015-08-05

Electrohydrodynamic-inkjet-printed high-resolution complex 3D structures with multiple functional inks are demonstrated. Printed 3D structures can have a variety of fine patterns, such as vertical or helix-shaped pillars and straight or rounded walls, with high aspect ratios (greater than ≈50) and narrow diameters (≈0.7 μm). Furthermore, the formation of freestanding, bridge-like Ag wire structures on plastic substrates suggests substantial potentials as high-precision, flexible 3D interconnects. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Synthesis of SnO2 pillared carbon using long chain alkylamine grafted graphene oxide: an efficient anode material for lithium ion batteries.

PubMed

Reddy, M Jeevan Kumar; Ryu, Sung Hun; Shanmugharaj, A M

2016-01-07

With the objective of developing new advanced composite materials that can be used as anodes for lithium ion batteries (LIBs), herein we describe the synthesis of SnO2 pillared carbon using various alkylamine (hexylamine; dodecylamine and octadecylamine) grafted graphene oxides and butyl trichlorotin precursors followed by its calcination at 500 °C for 2 h. While the grafted alkylamine induces crystalline growth of SnO2 pillars, thermal annealing of alkylamine grafted graphene oxide results in the formation of amorphous carbon coated graphene. Field emission scanning electron microscopy (FE-SEM) results reveal the successful formation of SnO2 pillared carbon on the graphene surface. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy characterization corroborates the formation of rutile SnO2 crystals on the graphene surface. A significant rise in the BET surface area is observed for SnO2 pillared carbon, when compared to pristine GO. Electrochemical characterization studies of SnO2 pillared carbon based anode materials showed an enhanced lithium storage capacity and fine cyclic performance in comparison with pristine GO. The initial specific capacities of SnO2 pillared carbon are observed to be 1379 mA h g(-1), 1255 mA h g(-1) and 1360 mA h g(-1) that decrease to 750 mA h g(-1), 643 mA h g(-1) and 560 mA h g(-1) depending upon the chain length of grafted alkylamine on the graphene surface respectively. Electrochemical impedance spectral analysis reveals that the exchange current density of SnO2 pillared carbon based electrodes is higher, corroborating its enhanced electrochemical activity in comparison with GO based electrodes.

The rapid growth of vertically aligned carbon nanotubes using laser heating.

PubMed

Park, J B; Jeong, S H; Jeong, M S; Lim, S C; Lee, I H; Lee, Y H

2009-05-06

Growth of densely packed vertically aligned carbon nanotubes (VA-CNTs) using laser-induced chemical vapor deposition with visible laser (lambda = 532 nm) irradiation at room temperature is reported. Using a multiple-catalyst layer (Fe/Al/Cr) on quartz as the substrate and an acetylene-hydrogen mixture as the precursor gas, VA-CNT pillars with 60 microm height and 4 microm diameter were grown at a high rate of around 1 microm s(-1) with good reproducibility. It is demonstrated that the fabrication of uniform pillar arrays of VA-CNTs can be achieved with a single irradiation for each pillar using LCVD with no annealing or preprocessing of the substrate. Here, laser fast heating is considered the primary mechanism facilitating the growth of VA-CNT pillars. Field emission characteristics of an array of VA-CNT pillars were then examined to investigate their potential application in vacuum electronic devices.

Design and construction of porous metal-organic frameworks based on flexible BPH pillars

NASA Astrophysics Data System (ADS)

Hao, Xiang-Rong; Yang, Guang-sheng; Shao, Kui-Zhan; Su, Zhong-Min; Yuan, Gang; Wang, Xin-Long

2013-02-01

Three metal-organic frameworks (MOFs), [Co2(BPDC)2(4-BPH)·3DMF]n (1), [Cd2(BPDC)2(4-BPH)2·2DMF]n (2) and [Ni2(BDC)2(3-BPH)2 (H2O)·4DMF]n (3) (H2BPDC=biphenyl-4,4'-dicarboxylic acid, H2BDC=terephthalic acid, BPH=bis(pyridinylethylidene)hydrazine and DMF=N,N'-dimethylformamide), have been solvothermally synthesized based on the insertion of heterogeneous BPH pillars. Framework 1 has "single-pillared" MOF-5-like motif with inner cage diameters of up to 18.6 Å. Framework 2 has "double pillared" MOF-5-like motif with cage diameters of 19.2 Å while 3 has "double pillared" 8-connected framework with channel diameters of 11.0 Å. Powder X-ray diffraction (PXRD) shows that 3 is a dynamic porous framework.

Use of epoxy-embedded electrodes to integrate electrochemical detection with microchip-based analysis systems.

PubMed

Selimovic, Asmira; Johnson, Alicia S; Kiss, István Z; Martin, R Scott

2011-04-01

A new method of fabricating electrodes for microchip devices that involves the use of Teflon molds and a commercially available epoxy to embed electrodes of various sizes and compositions is described. The resulting epoxy base can be polished to generate a fresh electrode and sealed against poly(dimethylsiloxane) (PDMS)-based fluidic structures. Microchip-based flow injection analysis was used to characterize the epoxy-embedded electrodes. It was shown that gold electrodes can be amalgamated with liquid mercury and the resulting mercury/gold electrode is used to selectively detect glutathione from lysed red blood cells. The ability to encapsulate multiple electrode materials of differing compositions enabled the integration of microchip electrophoresis with electrochemical detection. Finally, a unique feature of this approach is that the electrode connection is made from the bottom of the epoxy base. This enables the creation of three-dimensional gold pillar electrodes (65 μm in diameter and 27 μm in height) that can be integrated within a fluidic network. As compared with the use of a flat electrode of a similar diameter, the use of the pillar electrode led to improvements in both the sensitivity (72.1 pA/μM for the pillar versus 4.2 pA/μM for the flat electrode) and limit of detection (20 nM for the pillar versus 600 nM for the flat electrode), with catechol being the test analyte. These epoxy-embedded electrodes hold promise for the creation of inexpensive microfluidic devices that can be used to electrochemically detect biologically important analytes in a manner where the electrodes can be polished and a fresh electrode surface is generated as desired. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Effect of sulfuric acid concentration of bentonite and calcination time of pillared bentonite

NASA Astrophysics Data System (ADS)

Mara, Ady; Wijaya, Karna; Trisunaryati, Wega; Mudasir

2016-04-01

An activation of natural clay has been developed. Activation was applied by refluxing the natural bentonite in variation of the sulfuric acid concentration and calcination time of pillared bentonite (PLC). Calcination was applied using oven in microwave 2,45 GHz. Determination of acidity was applied by measuring the amount of adsorbed ammonia and pyridine. Morphological, functional groups and chrystanility characterizations were analyzed using SEM, TEM, FTIR and XRD. Porosity was analyzed using SSA. The results showed that the greater of the concentration of sulfuric acid and calcination time was, the greater the acidity of bentonite as well as the pore diameter were. FTIR spectra showed no fundamental changes in the structure of the natural bentonite, SEM, and TEM images were showing an increase in space or field due to pillarization while the XRD patterns showed a shift to a lower peak. Optimization was obtained at a concentration of 2 M of sulfuric acid and calcination time of 20 minutes, keggin ion of 2.2 and suspension of 10 mmol, respectively each amounted to 11.7490 mmol/gram of ammonia and 2.4437 mmol/gram of pyridine with 154.6391 m2/gram for surface area, 0.130470 m3/gram of pore volume and 3.37484 nm of pore diameter.

Evaluation of friction enhancement through soft polymer micro-patterns in active capsule endoscopy

NASA Astrophysics Data System (ADS)

Buselli, Elisa; Pensabene, Virginia; Castrataro, Piero; Valdastri, Pietro; Menciassi, Arianna; Dario, Paolo

2010-10-01

Capsule endoscopy is an emerging field in medical technology. Despite very promising innovations, some critical issues are yet to be addressed, such as the management and possible exploitation of the friction in the gastrointestinal environment in order to control capsule locomotion more actively. This paper presents the fabrication and testing of bio-inspired polymeric micro-patterns, which are arrays of cylindrical pillars fabricated via soft lithography. The aim of the work is to develop structures that enhance the grip between an artificial device and the intestinal tissue, without injuring the mucosa. In fact, the patterns are intended to be mounted on microfabricated legs of a capsule robot that is able to move actively in the gastrointestinal tract, thus improving the robot's traction ability. The effect of micro-patterned surfaces on the leg-slipping behaviour on colon walls was investigated by considering both different pillar dimensions and the influence of tissue morphology. Several in vitro tests on biological samples demonstrated that micro-patterns of pillars made from a soft polymer with an aspect ratio close to 1 enhanced friction by 41.7% with regard to flat surfaces. This work presents preliminary modelling of the friction and adhesion forces in the gastrointestinal environment and some design guidelines for endoscopic devices.

Preparation of Pillar[5]arene-Based [2]Rotaxanes by a Stopper-Exchange Strategy.

PubMed

Nierengarten, Iwona; Meichsner, Eric; Holler, Michel; Pieper, Pauline; Deschenaux, Robert; Delavaux-Nicot, Béatrice; Nierengarten, Jean-François

2018-01-02

A pillar[5]arene-containing rotaxane building block bearing exchangeable stoppers has been prepared in multigram scale quantities with high yields from the reaction of 2,4-dinitrophenol (DNP) with the inclusion complex resulting from the association of dodecanedioyl chloride with 1,4-diethoxypillar[5]arene. Stopper exchange reactions have been achieved by treatment of the resulting DNP diester with various amines through an addition-elimination mechanism preventing the unthreading of the axle component during the reaction and thus preserving the [2]rotaxane structures. The resulting diamide [2]rotaxane derivatives have thus been obtained in good to excellent yields. Importantly, [2]rotaxanes difficult or impossible to prepare by direct introduction of the two stoppers in a single synthetic step are now easily available. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

DSA patterning options for logics and memory applications

NASA Astrophysics Data System (ADS)

Liu, Chi-Chun; Franke, Elliott; Mignot, Yann; LeFevre, Scott; Sieg, Stuart; Chi, Cheng; Meli, Luciana; Parnell, Doni; Schmidt, Kristin; Sanchez, Martha; Singh, Lovejeet; Furukawa, Tsuyoshi; Seshadri, Indira; De Silva, Ekmini Anuja; Tsai, Hsinyu; Lai, Kafai; Truong, Hoa; Farrell, Richard; Bruce, Robert; Somervell, Mark; Sanders, Daniel; Felix, Nelson; Arnold, John; Hetzer, David; Ko, Akiteru; Metz, Andrew; Colburn, Matthew; Corliss, Daniel

2017-03-01

The progress of three potential DSA applications, i.e. fin formation, via shrink, and pillars, were reviewed in this paper. For fin application, in addition to pattern quality, other important considerations such as customization and design flexibility were discussed. An electrical viachain study verified the DSA rectification effect on CD distribution by showing a tighter current distribution compared to that derived from the guiding pattern direct transfer without using DSA. Finally, a structural demonstration of pillar formation highlights the importance of pattern transfer in retaining both the CD and local CDU improvement from DSA. The learning from these three case studies can provide perspectives that may not have been considered thoroughly in the past. By including more important elements during DSA process development, the DSA maturity can be further advanced and move DSA closer to HVM adoption.

Driving Turbulence and Triggering Star Formation by Ionizing Radiation

NASA Astrophysics Data System (ADS)

Gritschneder, Matthias; Naab, Thorsten; Walch, Stefanie; Burkert, Andreas; Heitsch, Fabian

2009-03-01

We present high-resolution simulations on the impact of ionizing radiation of massive O stars on the surrounding turbulent interstellar medium (ISM). The simulations are performed with the newly developed software iVINE which combines ionization with smoothed particle hydrodynamics (SPH) and gravitational forces. We show that radiation from hot stars penetrates the ISM, efficiently heats cold low-density gas and amplifies overdensities seeded by the initial turbulence. The formation of observed pillar-like structures in star-forming regions (e.g. in M16) can be explained by this scenario. At the tip of the pillars gravitational collapse can be induced, eventually leading to the formation of low-mass stars. Detailed analysis of the evolution of the turbulence spectra shows that UV radiation of O stars indeed provides an excellent mechanism to sustain and even drive turbulence in the parental molecular cloud.

Flexible pillared graphene-paper electrodes for high-performance electrochemical supercapacitors.

PubMed

Wang, Gongkai; Sun, Xiang; Lu, Fengyuan; Sun, Hongtao; Yu, Mingpeng; Jiang, Weilin; Liu, Changsheng; Lian, Jie

2012-02-06

Flexible graphene paper (GP) pillared by carbon black (CB) nanoparticles using a simple vacuum filtration method is developed as a high-performance electrode material for supercapacitors. Through the introduction of CB nanoparticles as spacers, the self-restacking of graphene sheets during the filtration process is mitigated to a great extent. The pillared GP-based supercapacitors exhibit excellent electrochemical performances and cyclic stabilities compared with GP without the addition of CB nanoparticles. At a scan rate of 10 mV s(-1) , the specific capacitance of the pillared GP is 138 F g(-1) and 83.2 F g(-1) with negligible 3.85% and 4.35% capacitance degradation after 2000 cycles in aqueous and organic electrolytes, respectively. At an extremely fast scan rate of 500 mV s (-1) , the specific capacitance can reach 80 F g(-1) in aqueous electrolyte. No binder is needed for assembling the supercapacitor cells and the pillared GP itself may serve as a current collector due to its intrinsic high electrical conductivity. The pillared GP has great potential in the development of promising flexible and ultralight-weight supercapacitors for electrochemical energy storage. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Stress-strain relationship of PDMS micropillar for force measurement application

NASA Astrophysics Data System (ADS)

Johari, Shazlina; Shyan, L. Y.

2017-11-01

There is an increasing interest to use polydimethylsiloxane (PDMS) based materials as bio-transducers for force measurements in the order of micro to nano Newton. The accuracy of these devices relies on appropriate material characterization of PDMS and modelling to convert the micropillar deformations into the corresponding forces. Previously, we have reported on fabricated PDMS micropillar that acts as a cylindrical cantilever and was experimentally used to measure the force of the nematode C. elegans. In this research, similar PDMS micropillars are designed and simulated using ANSYS software. The simulation involves investigating two main factors that is expected to affect the force measurement performance; pillar height and diameter. Results show that the deformation increases when pillar height is increased and the deformation is inversely proportional to the pillar diameter. The maximum deformation obtained is 713 um with pillar diameter of 20 um and pillar height of 100 um. Results of stress and strain show similar pattern, where their values decreases as pillar diameter and height is increased. The simulated results are also compared with the calculated displacement. The trend for both calculated and simulated values are similar with 13% average difference.

Flexible Pillared Graphene-Paper Electrodes for High-Performance Electrochemical Supercapacitors

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

Wang, Gongkai; Sun, Xiang; Lu, Fengyuan

2011-12-08

Flexible graphene paper (GP) pillared by carbon black (CB) nanoparticles using a simple vacuum filtration method is developed as a high-performance electrode material for supercapacitors. Through the introduction of CB nanoparticles as spacers, the self-restacking of graphene sheets during the filtration process is mitigated to a great extent. The pillared GP-based supercapacitors exhibit excellent electrochemical performances and cyclic stabilities compared with GP without the addition of CB nanoparticles. At a scan rate of 10 mV s -1, the specific capacitance of the pillared GP is 138 F g -1 and 83.2 F g -1 with negligible 3.85% and 4.35% capacitancemore » degradation after 2000 cycles in aqueous and organic electrolytes, respectively. At an extremely fast scan rate of 500 mV s -1, the specific capacitance can reach 80 F g -1 in aqueous electrolyte. No binder is needed for assembling the supercapacitor cells and the pillared GP itself may serve as a current collector due to its intrinsic high electrical conductivity. Finally, the pillared GP has great potential in the development of promising flexible and ultralight-weight supercapacitors for electrochemical energy storage.« less

Estimating the coordinates of pillars and posts in the parking lots for intelligent parking assist system

NASA Astrophysics Data System (ADS)

Choi, Jae Hyung; Kuk, Jung Gap; Kim, Young Il; Cho, Nam Ik

2012-01-01

This paper proposes an algorithm for the detection of pillars or posts in the video captured by a single camera implemented on the fore side of a room mirror in a car. The main purpose of this algorithm is to complement the weakness of current ultrasonic parking assist system, which does not well find the exact position of pillars or does not recognize narrow posts. The proposed algorithm is consisted of three steps: straight line detection, line tracking, and the estimation of 3D position of pillars. In the first step, the strong lines are found by the Hough transform. Second step is the combination of detection and tracking, and the third is the calculation of 3D position of the line by the analysis of trajectory of relative positions and the parameters of camera. Experiments on synthetic and real images show that the proposed method successfully locates and tracks the position of pillars, which helps the ultrasonic system to correctly locate the edges of pillars. It is believed that the proposed algorithm can also be employed as a basic element for vision based autonomous driving system.

Synthesis of SnO2 pillared carbon using long chain alkylamine grafted graphene oxide: an efficient anode material for lithium ion batteries

NASA Astrophysics Data System (ADS)

Reddy, M. Jeevan Kumar; Ryu, Sung Hun; Shanmugharaj, A. M.

2015-12-01

With the objective of developing new advanced composite materials that can be used as anodes for lithium ion batteries (LIBs), herein we describe the synthesis of SnO2 pillared carbon using various alkylamine (hexylamine; dodecylamine and octadecylamine) grafted graphene oxides and butyl trichlorotin precursors followed by its calcination at 500 °C for 2 h. While the grafted alkylamine induces crystalline growth of SnO2 pillars, thermal annealing of alkylamine grafted graphene oxide results in the formation of amorphous carbon coated graphene. Field emission scanning electron microscopy (FE-SEM) results reveal the successful formation of SnO2 pillared carbon on the graphene surface. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy characterization corroborates the formation of rutile SnO2 crystals on the graphene surface. A significant rise in the BET surface area is observed for SnO2 pillared carbon, when compared to pristine GO. Electrochemical characterization studies of SnO2 pillared carbon based anode materials showed an enhanced lithium storage capacity and fine cyclic performance in comparison with pristine GO. The initial specific capacities of SnO2 pillared carbon are observed to be 1379 mA h g-1, 1255 mA h g-1 and 1360 mA h g-1 that decrease to 750 mA h g-1, 643 mA h g-1 and 560 mA h g-1 depending upon the chain length of grafted alkylamine on the graphene surface respectively. Electrochemical impedance spectral analysis reveals that the exchange current density of SnO2 pillared carbon based electrodes is higher, corroborating its enhanced electrochemical activity in comparison with GO based electrodes.With the objective of developing new advanced composite materials that can be used as anodes for lithium ion batteries (LIBs), herein we describe the synthesis of SnO2 pillared carbon using various alkylamine (hexylamine; dodecylamine and octadecylamine) grafted graphene oxides and butyl trichlorotin precursors followed by its calcination at 500 °C for 2 h. While the grafted alkylamine induces crystalline growth of SnO2 pillars, thermal annealing of alkylamine grafted graphene oxide results in the formation of amorphous carbon coated graphene. Field emission scanning electron microscopy (FE-SEM) results reveal the successful formation of SnO2 pillared carbon on the graphene surface. X-ray diffraction (XRD), transmission electron microscopy (TEM) and Raman spectroscopy characterization corroborates the formation of rutile SnO2 crystals on the graphene surface. A significant rise in the BET surface area is observed for SnO2 pillared carbon, when compared to pristine GO. Electrochemical characterization studies of SnO2 pillared carbon based anode materials showed an enhanced lithium storage capacity and fine cyclic performance in comparison with pristine GO. The initial specific capacities of SnO2 pillared carbon are observed to be 1379 mA h g-1, 1255 mA h g-1 and 1360 mA h g-1 that decrease to 750 mA h g-1, 643 mA h g-1 and 560 mA h g-1 depending upon the chain length of grafted alkylamine on the graphene surface respectively. Electrochemical impedance spectral analysis reveals that the exchange current density of SnO2 pillared carbon based electrodes is higher, corroborating its enhanced electrochemical activity in comparison with GO based electrodes. Electronic supplementary information (ESI) available: XPS, FE-SEM, FE-TEM, TGA FT-IR, EIS, CV of and charge discharge profiles of RGO-SnO2 composites. See DOI: 10.1039/c5nr06680h

Label-Free Detection of Live Cancer Cells and DNA Hybridization using 3D Multilayered Plasmonic Biosensor.

PubMed

Zhu, Shuyan; Li, Hualin; Yang, Mengsu; Pang, Stella W

2018-05-31

Three-dimensional (3D) multilayered plasmonic structures consisting of Au submicrometric squares on top of SU-8 submicrometric pillars, Au asymmetrical submicrometric structures in the middle, and Au asymmetrical submicrometric holes at the bottom were fabricated through reversal nanoimprint technology. Compared with two-dimensional and quasi-3D plasmonic structures, the 3D multilayered plasmonic structures showed higher electromagnetic field intensity, longer plasmon decay length and larger plasmon sensing area, which are desirable for highly sensitive localized surface plasmonic resonance biosensors. The sensitivity and resonance peak wavelength of the 3D multilayered plasmonic structures could be adjusted by varying the offset between the top and bottom SU-8 submicrometric pillars from 31% to 56%, and the highest sensitivity of 382 and 442 nm/refractive index unit were observed for resonance peaks at 581 and 805 nm, respectively. Live lung cancer A549 cells with a low concentration of 5×103 cells/ml and a low sample volume of 2 µl could be detected by the 3D multilayered plasmonic structures integrated in a microfluidic system. The 3D plasmonic biosensors also had the advantages of detecting DNA hybridization by capturing the complementary target DNA in the low concentration range of 10-14 to 10-7 M, and providing a large peak shift of 82 nm for capturing 10-7 M complementary target DNA without additional signal amplification. Creative Commons Attribution license.

Recovery opportunities for metals and energy from sewage sludges.

PubMed

Mulchandani, Anjali; Westerhoff, Paul

2016-09-01

Limitations on current wastewater treatment plant (WWTP) biological processes and solids disposal options present opportunities to implement novel technologies that convert WWTPs into resource recovery facilities. This review considered replacing or augmenting extensive dewatering, anaerobic digestion, and off-site disposal with new thermo-chemical and liquid extraction processes. These technologies may better recover energy and metals while inactivating pathogens and destroying organic pollutants. Because limited direct comparisons between different sludge types exist in the literature for hydrothermal liquefaction, this study augments the findings with experimental data. These experiments demonstrated 50% reduction in sludge mass, with 30% of liquefaction products converted to bio-oil and most metals sequestered within a small mass of solid bio-char residue. Finally, each technology's contribution to the three sustainability pillars is investigated. Although limiting hazardous materials reintroduction to the environment may increase economic cost of sludge treatment, it is balanced by cleaner environment and valuable resource benefits for society. Copyright © 2016 Elsevier Ltd. All rights reserved.

Formation of structures around HII regions: ionization feedback from massive stars

NASA Astrophysics Data System (ADS)

Tremblin, P.; Audit, E.; Minier, V.; Schmidt, W.; Schneider, N.

2015-03-01

We present a new model for the formation of dense clumps and pillars around HII regions based on shocks curvature at the interface between a HII region and a molecular cloud. UV radiation leads to the formation of an ionization front and of a shock ahead. The gas is compressed between them forming a dense shell at the interface. This shell may be curved due to initial interface or density modulation caused by the turbulence of the molecular cloud. Low curvature leads to instabilities in the shell that form dense clumps while sufficiently curved shells collapse on itself to form pillars. When turbulence is high compared to the ionized-gas pressure, bubbles of cold gas have sufficient kinetic energy to penetrate into the HII region and detach themselves from the parent cloud, forming cometary globules. Using computational simulations, we show that these new models are extremely efficient to form dense clumps and stable and growing elongated structures, pillars, in which star formation might occur (see Tremblin et al. 2012a). The inclusion of turbulence in the model shows its importance in the formation of cometary globules (see Tremblin et al. 2012b). Globally, the density enhancement in the simulations is of one or two orders of magnitude higher than the density enhancement of the classical ``collect and collapse`` scenario. The code used for the simulation is the HERACLES code, that comprises hydrodynamics with various equation of state, radiative transfer, gravity, cooling and heating. Our recent observations with Herschel (see Schneider et al. 2012a) and SOFIA (see Schneider et al. 2012b) and additional Spitzer data archives revealed many more of these structures in regions where OB stars have already formed such as the Rosette Nebula, Cygnus X, M16 and Vela, suggesting that the UV radiation from massive stars plays an important role in their formation. We present a first comparison between the simulations described above and recent observations of these regions.

A novel porous anionic metal–organic framework with pillared double-layer structure for selective adsorption of dyes

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

Sheng, Shu-Nan; Han, Yi; Wang, Bin

2016-01-15

A novel porous anionic metal–organic framework, (Me{sub 2}NH{sub 2}){sub 2}[Zn{sub 2}L{sub 1.5}bpy]·2DMF (BUT-201; H{sub 4}L=4,8-disulfonaphthalene-2,6-dicarboxylic acid; bpy=4,4-bipyridine; DMF=N,N-dimethylformamide), with pillared double-layer structure has been synthesized through the reaction of a sulfonated carboxylic acid ligand and Zn(NO{sub 3}){sub 2}·6H{sub 2}O with 4,4-bipyridine as a co-ligand. It is found that BUT-201 can rapidly adsorb cationic dyes with a smaller size such as Methylene Blue (MB) and Acriflavine Hydrochloride (AH) by substitution of guest (CH{sub 3}){sub 2}NH{sub 2}{sup +}, but has no adsorption towards the cationic dyes with a lager size such as Methylene Violet (MV), the anionic dyes like C. I. Acidmore » Yellow 1 (AY1) and neutral dyes like C. I. Solvent Yellow 7 (SY7), respectively. The results show that the adsorption behavior of BUT-201 relates not only to the charge but also to the size/shape of dyes. Furthermore, the adsorbed dyes can be gradually released in the methanol solution of LiNO{sub 3}. - Graphical abstract: A porous anionic metal–organic framework (BUT-201) can selectively adsorb the cationic dyes by cationic guest molecule substitution, and the adsorbed dyes can be gradually released in the methanol solution of LiNO{sub 3}. - Highlights: • An anionic metal-organic framework (BUT-201) has been synthesized and characterized. • BUT-201 has a three-dimensional (3D) pillared double-layer structure. • BUT-201 can selectively and rapidly adsorb cationic dyes. • The adsorbed dyes can be gradually released in the methanol solution of LiNO{sub 3}.« less

"Learning to Do" as a Pillar of Education and Its Links to Entrepreneurial Studies in Higher Education: European Contexts and Approaches

ERIC Educational Resources Information Center

Miclea, Mircea

2004-01-01

The author links the "learning to do" pillar, one of the four pillars of the Delors Report of 1996 , "Learning: The Treasure Within", to the principles and purposes of an entrepreneurial university and the aims of the European Commission and the Bologna Process to enhance the employability of graduates of higher education. An entrepreneurial…

Advancing the Interdisciplinary Collaborative Health Team Model: Applying Democratic Professionalism, Implementation Science, and Therapeutic Alliance to Enact Social Justice Practice.

PubMed

Murphy, Nancy

2015-01-01

This essay reframes the interdisciplinary collaborative health team model by proposing the application of 3 foundational pillars-democratic professionalism, implementation science, and therapeutic alliance to advance this practice. The aim was to address challenges to the model, enhance their functional capacity, and explicate and enact social justice practices to affect individual health outcomes while simultaneously addressing health inequities. The pillars are described and examples from the author's dissertation research illustrate how the pillars were used to bring about action. Related theories, models, and frameworks that have negotiation, capacity building, collaboration, and knowledge/task/power sharing as central concepts are presented under each of the pillars.

Design, fabrication and test of a pneumatically controlled, renewable, microfluidic bead trapping device for sequential injection analysis applications

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

Shao, Guocheng; Lu, Donglai; Fu, Zhifeng

This paper describes the design, fabrication, and testing of a pneumatically controlled,renewable, microfluidic device for conducting bead-based assays in an automated sequential injection analysis system. The device used a “brick wall”-like pillar array (pillar size: 20 μm length X 50 μm width X 45 μm height) with 5 μm gaps between the pillars serving as the micro filter. The flow channel where bead trapping occurred is 500 μm wide X 75 μm deep. An elastomeric membrane and an air chamber were located underneath the flow channel. By applying pressure to the air chamber, the membrane is deformed and pushed upwardmore » against the filter structure. This effectively traps beads larger than 5 μm and creates a “bed” or micro column of beads that can be perfused and washed with liquid samples and reagents. Upon completion of the assay process, the pressure is released and the beads are flushed out from underneath the filter structure to renew the device. Mouse IgG was used as a model analyte to test the feasibility of using the proposed device for immunoassay applications. Resulting microbeads from an on-chip fluorescent immunoassay were individually examined using flow cytometry. The results show that the fluorescence signal intensity distribution is fairly narrow indicating high chemical reaction uniformity among the beads population. Electrochemical onchip assay was also conducted. A detection limit of 0.1 ng/mL1 ppb was achieved and good device reliability and repeatability were demonstrated. The novel microfluidic-based beadstrapping device thus opens up a new pathway to design micro-bead based biosensor immunoassays for clinical and othervarious applications.« less

Schools and Disasters: Safety and Mental Health Assessment and Interventions for Children.

PubMed

Lai, Betty S; Esnard, Ann-Margaret; Lowe, Sarah R; Peek, Lori

2016-12-01

This article draws on experiences and lessons from global disasters and utilizes the United Nations Comprehensive School Safety Framework to highlight the necessary role of safe schools in protecting children, as well as adult staff, from the immediate threats and long-term implications of disasters. Specifically, we focus on three well-established pillars of school safety: Pillar I: Safe Learning Facilities; Pillar II: Disaster Management; and Pillar III: Risk Reduction and Resilience Education. In addition, we propose a potential fourth pillar, which underscores the function of schools in postdisaster mental health assessment and intervention for children. We argue that schools offer a central location and trusted institutional space for mental health assessment and intervention after disasters. We also examine the important linkages between schools, child mental health, and household and family recovery. We conclude with recommendations for filling gaps in research and practice related to ensuring the safety of schools and the associated health and well-being of children in the face of future disasters.

NASA's Aero-Space Technology

NASA Technical Reports Server (NTRS)

Milstead, Phil

2000-01-01

This presentation reviews the three pillars and the associated goals of NASA's Aero-Space Technology Enterprise. The three pillars for success are: (1) Global Civil Aviation, (2) Revolutionary Technology Leaps, (3) Advanced Space Transportation. The associated goals of the first pillar are to reduce accidents, emissions, and cost, and to increase the aviation system capacity. The goals of the second pillar are to reduce transoceanic travel time, revolutionize general aviation aircraft, and improve development capacity. The goals associated with the third pillar are to reduce the launch cost for low earth orbit and to reduce travel time for planetary missions. In order to meet these goals NASA must provide next-generation design capability for new and or experimental craft which enable a balance between reducing components of the design cycle by up to 50% and or increasing the confidence in design by 50%. These next-generation design tools, concepts, and processes will revolutionize vehicle development. The presentation finally reviews the importance of modeling and simulation in achieving the goals.

Wetting state and maximum spreading factor of microdroplets impacting on superhydrophobic textured surfaces with anisotropic arrays of pillars

NASA Astrophysics Data System (ADS)

Kwon, Dae Hee; Huh, Hyung Kyu; Lee, Sang Joon

2013-07-01

The dynamic behaviors of microdroplets that impact on textured surfaces with various patterns of microscale pillars are experimentally investigated in this study. A piezoelectric inkjet is used to generate the microdroplets that have a diameter of less than 46 μm and a controlled Weber number. The impact and spreading dynamics of an individual droplet are captured by using a high-speed imaging system. The anisotropic and directional wettability and the wetting states on the textured surfaces with anisotropically arranged pillars are revealed for the first time in this study. The impalement transition from the Cassie-Baxter state to the partially impaled state is evaluated by balancing the wetting pressure P wet and the capillary pressure P C even on the anisotropic textured surfaces. The maximum spreading factor is measured and compared with the theoretical prediction to elucidate the wettability of the textured surfaces. For a given Weber number, the maximum spreading factor decreases as the texture area fraction of the textured surface decreases. In addition, the maximum spreading factors along the direction of longer inter-pillar spacing always have smaller values than those along the direction of shorter inter-pillar spacing when a droplet impacts on the anisotropic arrays of pillars.

Personalized physiological medicine.

PubMed

Ince, Can

2017-12-28

This paper introduces the concept of personalized physiological medicine that is specifically directed at the needs of the critically ill patient. This differs from the conventional view of personalized medicine, characterized by biomarkers and gene profiling, instead focusing on time-variant changes in the pathophysiology and regulation of various organ systems and their cellular and subcellular constituents. I propose that personalized physiological medicine is composed of four pillars relevant to the critically ill patient. Pillar 1 is defined by the frailty and fitness of the patient and their physiological reserve to cope with the stress of critical illness and therapy. Pillar 2 involves monitoring of the key physiological variables of the different organ systems and their response to disease and therapy. Pillar 3 concerns the evaluation of the success of resuscitation by assessment of the hemodynamic coherence between the systemic and microcirculation and parenchyma of the organ systems. Finally, pillar 4 is defined by the integration of the physiological and clinical data into a time-learning adaptive model of the patient to provide feedback about the function of organ systems and to guide and assess the response to disease and therapy. I discuss each pillar and describe the challenges to research and development that will allow the realization of personalized physiological medicine to be practiced at the bedside for critically ill patients.

Deformation twinning in Ni–Mn–Ga micropillars with 10M martensite

PubMed Central

Reinhold, M.; Kiener, D.; Knowlton, W. B.; Dehm, G.; Müllner, P.

2009-01-01

The maximum actuation frequency of magnetic shape-memory alloys (MSMAs) significantly increases with decreasing size of the transducer making MSMAs interesting candidates for small scale actuator applications. To study the mechanical properties of Ni–Mn–Ga single crystals on small length scales, two single-domain micropillars with dimensions of 10×15×30 μm3 were fabricated from a Ni–Mn–Ga monocrystal using dual beam focused ion beam machining. The pillars were oriented such that the crystallographic c direction was perpendicular to the loading direction. The pillars were compressed to maximum stresses of 350 and 50 MPa, respectively. Atomic force microscopy and magnetic force microscopy were performed prior to fabrication of the pillars and following the deformation experiments. Both micropillars were deformed by twinning as evidenced by the stress-strain curve. For one pillar, a permanent deformation of 3.6% was observed and ac twins (10M martensite) were identified after unloading. For the other pillar, only 0.7% remained upon unloading. No twins were found in this pillar after unloading. The recovery of deformation is discussed in the light of pseudoelastic twinning and twin-substrate interaction. The twinning stress was higher than in similar macroscopic material. However, further studies are needed to substantiate a size effect. PMID:19859577

Advanced hole patterning technology using soft spacer materials (Conference Presentation)

NASA Astrophysics Data System (ADS)

Park, Jong Keun; Hustad, Phillip D.; Aqad, Emad; Valeri, David; Wagner, Mike D.; Li, Mingqi

2017-03-01

A continuing goal in integrated circuit industry is to increase density of features within patterned masks. One pathway being used by the device manufacturers for patterning beyond the 80nm pitch limitation of 193 immersion lithography is the self-aligned spacer double patterning (SADP). Two orthogonal line space patterns with subsequent SADP can be used for contact holes multiplication. However, a combination of two immersion exposures, two spacer deposition processes, and two etch processes to reach the desired dimensions makes this process expensive and complicated. One alternative technique for contact hole multiplication is the use of an array of pillar patterns. Pillars, imaged with 193 immersion photolithography, can be uniformly deposited with spacer materials until a hole is formed in the center of 4 pillars. Selective removal of the pillar core gives a reversal of phases, a contact hole where there was once a pillar. However, the highly conformal nature of conventional spacer materials causes a problem with this application. The new holes, formed between 4 pillars, by this method have a tendency to be imperfect and not circular. To improve the contact hole circularity, this paper presents the use of both conventional spacer material and soft spacer materials. Application of soft spacer materials can be achieved by an existing coating track without additional cost burden to the device manufacturers.

Superhydrophobic analyte concentration utilizing colloid-pillar array SERS substrates.

PubMed

Wallace, Ryan A; Charlton, Jennifer J; Kirchner, Teresa B; Lavrik, Nickolay V; Datskos, Panos G; Sepaniak, Michael J

2014-12-02

The ability to detect a few molecules present in a large sample is of great interest for the detection of trace components in both medicinal and environmental samples. Surface enhanced Raman spectroscopy (SERS) is a technique that can be utilized to detect molecules at very low absolute numbers. However, detection at trace concentration levels in real samples requires properly designed delivery and detection systems. The following work involves superhydrophobic surfaces that have as a framework deterministic or stochastic silicon pillar arrays formed by lithographic or metal dewetting protocols, respectively. In order to generate the necessary plasmonic substrate for SERS detection, simple and flow stable Ag colloid was added to the functionalized pillar array system via soaking. Native pillars and pillars with hydrophobic modification are used. The pillars provide a means to concentrate analyte via superhydrophobic droplet evaporation effects. A ≥ 100-fold concentration of analyte was estimated, with a limit of detection of 2.9 × 10(-12) M for mitoxantrone dihydrochloride. Additionally, analytes were delivered to the surface via a multiplex approach in order to demonstrate an ability to control droplet size and placement for scaled-up uses in real world applications. Finally, a concentration process involving transport and sequestration based on surface treatment selective wicking is demonstrated.

Deformation twinning in Ni-Mn-Ga micropillars with 10M martensite.

PubMed

Reinhold, M; Kiener, D; Knowlton, W B; Dehm, G; Müllner, P

2009-09-01

The maximum actuation frequency of magnetic shape-memory alloys (MSMAs) significantly increases with decreasing size of the transducer making MSMAs interesting candidates for small scale actuator applications. To study the mechanical properties of Ni-Mn-Ga single crystals on small length scales, two single-domain micropillars with dimensions of 10x15x30 mum(3) were fabricated from a Ni-Mn-Ga monocrystal using dual beam focused ion beam machining. The pillars were oriented such that the crystallographic c direction was perpendicular to the loading direction. The pillars were compressed to maximum stresses of 350 and 50 MPa, respectively. Atomic force microscopy and magnetic force microscopy were performed prior to fabrication of the pillars and following the deformation experiments. Both micropillars were deformed by twinning as evidenced by the stress-strain curve. For one pillar, a permanent deformation of 3.6% was observed and ac twins (10M martensite) were identified after unloading. For the other pillar, only 0.7% remained upon unloading. No twins were found in this pillar after unloading. The recovery of deformation is discussed in the light of pseudoelastic twinning and twin-substrate interaction. The twinning stress was higher than in similar macroscopic material. However, further studies are needed to substantiate a size effect.

Nanostructured silicon for thermoelectric

NASA Astrophysics Data System (ADS)

Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

2011-06-01

Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

Model-based design evaluation of a compact, high-efficiency neutron scatter camera

DOE PAGES

Weinfurther, Kyle; Mattingly, John; Brubaker, Erik; ...

2017-11-22

This paper presents the model-based design and evaluation of an instrument that estimates incident neutron direction using the kinematics of neutron scattering by hydrogen-1 nuclei in an organic scintillator. The instrument design uses a single, nearly contiguous volume of organic scintillator that is internally subdivided only as necessary to create optically isolated pillars, i.e., long, narrow parallelepipeds of organic scintillator. Scintillation light emitted in a given pillar is confined to that pillar by a combination of total internal reflection and a specular reflector applied to the four sides of the pillar transverse to its long axis. The scintillation light ismore » collected at each end of the pillar using a photodetector, e.g., a microchannel plate photomultiplier (MCPPM) or a silicon photomultiplier (SiPM). In this optically segmented design, the (x, y) position of scintillation light emission (where the x and y coordinates are transverse to the long axis of the pillars) is estimated as the pillar’s (x, y) position in the scintillator ‘‘block’’, and the z-position (the position along the pillar’s long axis) is estimated from the amplitude and relative timing of the signals produced by the photodetectors at each end of the pillar. The neutron’s incident direction and energy is estimated from the (x, y, z)-positions of two sequential neutron–proton scattering interactions in the scintillator block using elastic scatter kinematics. For proton recoils greater than 1 MeV, we show that the (x, y, z)-position of neutron–proton scattering can be estimated with < 1 cm root-mean-squared [RMS] error and the proton recoil energy can be estimated with < 50 keV RMS error by fitting the photodetectors’ response time history to models of optical photon transport within the scintillator pillars. Finally, we evaluate several alternative designs of this proposed single-volume scatter camera made of pillars of plastic scintillator (SVSC-PiPS), studying the effect of pillar dimensions, scintillator material (EJ-204, EJ-232Q and stilbene), and photodetector (MCP-PM vs. SiPM) response vs. time. Here, we demonstrate that the most precise estimates of incident neutron direction and energy can be obtained using a combination of scintillator material with high luminosity and a photodetector with a narrow impulse response. Specifically, we conclude that an SVSC-PiPS constructed using EJ-204 (a high luminosity plastic scintillator) and an MCP-PM will produce the most precise estimates of incident neutron direction and energy.« less

Model-based design evaluation of a compact, high-efficiency neutron scatter camera

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

Weinfurther, Kyle; Mattingly, John; Brubaker, Erik

This paper presents the model-based design and evaluation of an instrument that estimates incident neutron direction using the kinematics of neutron scattering by hydrogen-1 nuclei in an organic scintillator. The instrument design uses a single, nearly contiguous volume of organic scintillator that is internally subdivided only as necessary to create optically isolated pillars, i.e., long, narrow parallelepipeds of organic scintillator. Scintillation light emitted in a given pillar is confined to that pillar by a combination of total internal reflection and a specular reflector applied to the four sides of the pillar transverse to its long axis. The scintillation light ismore » collected at each end of the pillar using a photodetector, e.g., a microchannel plate photomultiplier (MCPPM) or a silicon photomultiplier (SiPM). In this optically segmented design, the (x, y) position of scintillation light emission (where the x and y coordinates are transverse to the long axis of the pillars) is estimated as the pillar’s (x, y) position in the scintillator ‘‘block’’, and the z-position (the position along the pillar’s long axis) is estimated from the amplitude and relative timing of the signals produced by the photodetectors at each end of the pillar. The neutron’s incident direction and energy is estimated from the (x, y, z)-positions of two sequential neutron–proton scattering interactions in the scintillator block using elastic scatter kinematics. For proton recoils greater than 1 MeV, we show that the (x, y, z)-position of neutron–proton scattering can be estimated with < 1 cm root-mean-squared [RMS] error and the proton recoil energy can be estimated with < 50 keV RMS error by fitting the photodetectors’ response time history to models of optical photon transport within the scintillator pillars. Finally, we evaluate several alternative designs of this proposed single-volume scatter camera made of pillars of plastic scintillator (SVSC-PiPS), studying the effect of pillar dimensions, scintillator material (EJ-204, EJ-232Q and stilbene), and photodetector (MCP-PM vs. SiPM) response vs. time. Here, we demonstrate that the most precise estimates of incident neutron direction and energy can be obtained using a combination of scintillator material with high luminosity and a photodetector with a narrow impulse response. Specifically, we conclude that an SVSC-PiPS constructed using EJ-204 (a high luminosity plastic scintillator) and an MCP-PM will produce the most precise estimates of incident neutron direction and energy.« less

Anisotropic Janus Si nanopillar arrays as a microfluidic one-way valve for gas-liquid separation

NASA Astrophysics Data System (ADS)

Wang, Tieqiang; Chen, Hongxu; Liu, Kun; Li, Yang; Xue, Peihong; Yu, Ye; Wang, Shuli; Zhang, Junhu; Kumacheva, Eugenia; Yang, Bai

2014-03-01

In this paper, we demonstrate a facile strategy for the fabrication of a one-way valve for microfluidic (MF) systems. The micro-valve was fabricated by embedding arrays of Janus Si elliptical pillars (Si-EPAs) with anisotropic wettability into a MF channel fabricated in poly(dimethylsiloxane) (PDMS). Two sides of the Janus pillar are functionalized with molecules with distinct surface energies. The ability of the Janus pillar array to act as a valve was proved by investigating the flow behaviour of water in a T-shaped microchannel at different flow rates and pressures. In addition, the one-way valve was used to achieve gas-liquid separation. We believe that the Janus Si-EPAs modified by specific surface functionalization provide a new strategy to control the flow and motion of fluids in MF channels.In this paper, we demonstrate a facile strategy for the fabrication of a one-way valve for microfluidic (MF) systems. The micro-valve was fabricated by embedding arrays of Janus Si elliptical pillars (Si-EPAs) with anisotropic wettability into a MF channel fabricated in poly(dimethylsiloxane) (PDMS). Two sides of the Janus pillar are functionalized with molecules with distinct surface energies. The ability of the Janus pillar array to act as a valve was proved by investigating the flow behaviour of water in a T-shaped microchannel at different flow rates and pressures. In addition, the one-way valve was used to achieve gas-liquid separation. We believe that the Janus Si-EPAs modified by specific surface functionalization provide a new strategy to control the flow and motion of fluids in MF channels. Electronic supplementary information (ESI) available: The XPS spectrum of the as-prepared Janus arrays after the MHA modification; the SEM images of the PFS-MHA Janus Si pillar arrays fabricated through oblique evaporation of gold along the short axis of the elliptical pillars; images of the cross-shaped MF channel and Rhodamine aqueous solution injecting in a cross-shaped MF channel taken at different times; the plot data of DPFS/DMHA against the flow rate of the aqueous solution; the plot data of failure pressure against the bottom size of the channel; optical microscopy images of the Janus pillar array with less density of pillars; optical microscopy images of the T junction with higher magnification; the video of Rhodamine solution running in the T-shaped microchannel integrated with the Janus Si-EPAs; the video of the entire gas-liquid separation process. See DOI: 10.1039/c3nr05865d

Atomistic study on shock behaviour of NiTi shape memory alloy

NASA Astrophysics Data System (ADS)

Yin, Qiuyun; Wu, Xianqian; Huang, Chenguang

2017-06-01

The shock behaviour of NiTi shape memory alloy is investigated by using molecular dynamics simulation. The nano-pillar samples of the alloy are subjected to the impact of a piston with a velocity of 350 m/s at initial environment temperatures of 325 and 500 K. At 325 K, we observe two different pathways of the formation of BCO phase, the gradient twins, and the detwinning phenomena, strongly depending on the local stress and the deformation state. As the initial temperature increases to 500 K, the plasticity is dominated by the dislocation movements rather than the twinning at 325 K. The phase transformation and plasticity result in stress attenuation when the stress wave propagates through the nano-pillar. Furthermore, it is interesting to note that multiple stress peaks occur due to the formation of local complex atomic structures with various wave speeds, leading to the catch up and overlap of the stress waves.

Structural optimization of interpenetrated pillared-layer coordination polymers for ethylene/ethane separation.

PubMed

Kishida, Keisuke; Horike, Satoshi; Watanabe, Yoshihiro; Tahara, Mina; Inubushi, Yasutaka; Kitagawa, Susumu

2014-06-01

With the goal of achieving effective ethylene/ethane separation, we evaluated the gas sorption properties of four pillared-layer-type porous coordination polymers with double interpenetration, [Zn2(tp)2(bpy)]n (1), [Zn2(fm)2(bpe)]n (2), [Zn2(fm)2(bpa)]n (3), and [Zn2(fm)2(bpy)]n (4) (tp = terephthalate, bpy = 4,4'-bipyridyl, fm = fumarate, bpe = 1,2-di(4-pyridyl)ethylene and bpa = 1,2-di(4-pyridyl)ethane). It was found that 4, which contains the narrowest pores of all of these compounds, exhibited ethylene-selective sorption profiles. The ethylene selectivity of 4 was estimated to be 4.6 at 298 K based on breakthrough experiments using ethylene/ethane gas mixtures. In addition, 4 exhibited a good regeneration ability compared with a conventional porous material. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vertical pillar-superlattice array and graphene hybrid light emitting diodes.

PubMed

Lee, Jung Min; Choung, Jae Woong; Yi, Jaeseok; Lee, Dong Hyun; Samal, Monica; Yi, Dong Kee; Lee, Chul-Ho; Yi, Gyu-Chul; Paik, Ungyu; Rogers, John A; Park, Won Il

2010-08-11

We report a type of device that combines vertical arrays of one-dimensional (1D) pillar-superlattice (PSL) structures with 2D graphene sheets to yield a class of light emitting diode (LED) with interesting mechanical, optical, and electrical characteristics. In this application, graphene sheets coated with very thin metal layers exhibit good mechanical and electrical properties and an ability to mount, in a freely suspended configuration, on the PSL arrays as a top window electrode. Optical characterization demonstrates that graphene exhibits excellent optical transparency even after deposition of the thin metal films. Thermal annealing of the graphene/metal (Gr/M) contact to the GaAs decreases the contact resistance, to provide enhanced carrier injection. The resulting PSL-Gr/M LEDs exhibit bright light emission over large areas. The result suggests the utility of graphene-based materials as electrodes in devices with unusual, nonplanar 3D architectures.

Microstructural and Mechanical Aspects of Reinforcement Welds for Lightweight Components Produced by Friction Hydro Pillar Processing

NASA Astrophysics Data System (ADS)

Pinheiro, Gustavo; dos Santos, Jorge; Hort, Norbert; Kainer, Karl Ulrich

The development of new creep resistant and cost effective die casting magnesium alloys such as AE, MRI, MEZ, ACM, AXJ, AJ, WE have emerged as an alternative to fulfil the actual demands in structural relevant applications as engines blocks, gear and converter boxes. However, magnesium components are in most of the cases screwed with aluminium and steel bolts, which lead the screwed joint to lose the preload force due to relaxation. This barrier limits thus the broad use of magnesium within this segment and should somehow find an adequate solution to be implemented and to help overcoming this limitation. In this context Friction Welding (FW) and particularly Friction Hydro Pillar Processing (FHPP), which can be described as a drill and fill process, appears as an alternative to widespread the use of magnesium. In this context, FHPP is intended to be used to locally reinforce mechanical fastened magnesium components.

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

DOE PAGES

Tian, Cheng; Cordeiro, Marco Aurelio L.; Lhermitte, Julien; ...

2017-05-25

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. We report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization.more » Furthermore, by controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.« less

Supra-Nanoparticle Functional Assemblies through Programmable Stacking

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

Tian, Cheng; Cordeiro, Marco Aurelio L.; Lhermitte, Julien

The quest for the by-design assembly of material and devices from nanoscale inorganic components is well recognized. Conventional self-assembly is often limited in its ability to control material morphology and structure simultaneously. We report a general method of assembling nanoparticles in a linear “pillar” morphology with regulated internal configurations. Our approach is inspired by supramolecular systems, where intermolecular stacking guides the assembly process to form diverse linear morphologies. Programmable stacking interactions were realized through incorporation of DNA coded recognition between the designed planar nanoparticle clusters. This resulted in the formation of multilayered pillar architectures with a well-defined internal nanoparticle organization.more » Furthermore, by controlling the number, position, size, and composition of the nanoparticles in each layer, a broad range of nanoparticle pillars were assembled and characterized in detail. In addition, we demonstrated the utility of this stacking assembly strategy for investigating plasmonic and electrical transport properties.« less

Terahertz Active Photonic Crystals for Condensed Gas Sensing

PubMed Central

Benz, Alexander; Deutsch, Christoph; Brandstetter, Martin; Andrews, Aaron M.; Klang, Pavel; Detz, Hermann; Schrenk, Werner; Strasser, Gottfried; Unterrainer, Karl

2011-01-01

The terahertz (THz) spectral region, covering frequencies from 1 to 10 THz, is highly interesting for chemical sensing. The energy of rotational and vibrational transitions of molecules lies within this frequency range. Therefore, chemical fingerprints can be derived, allowing for a simple detection scheme. Here, we present an optical sensor based on active photonic crystals (PhCs), i.e., the pillars are fabricated directly from an active THz quantum-cascade laser medium. The individual pillars are pumped electrically leading to laser emission at cryogenic temperatures. There is no need to couple light into the resonant structure because the PhC itself is used as the light source. An injected gas changes the resonance condition of the PhC and thereby the laser emission frequency. We achieve an experimental frequency shift of 10−3 times the center lasing frequency. The minimum detectable refractive index change is 1.6 × 10−5 RIU. PMID:22163939

Ionization impact on molecular clouds and star formation. Numerical simulations and observations

NASA Astrophysics Data System (ADS)

Tremblin, P.

2012-11-01

At all the scales of Astrophysics, the impact of the ionization from massive stars is a crucial issue. At the galactic scale, the ionization can regulate star formation by supporting molecular clouds against gravitational collapse and at the stellar scale, indications point toward a possible birth place of the Solar System close to massive stars. At the molecular cloud scale, it is clear that the hot ionized gas compresses the surrounding cold gas, leading to the formation of pillars, globules, and shells of dense gas in which some young stellar objects are observed. What are the formation mechanisms of these structures? Are the formation of these young stellar objects triggered or would have they formed anyway? Do massive stars have an impact on the distribution of the surrounding gas? Do they have an impact on the mass distribution of stars (the initial mass function, IMF)? This thesis aims at shedding some light on these questions, by focusing especially on the formation of the structures between the cold and the ionized gas. We present the state of the art of the theoretical and observational works on ionized regions (H ii regions) and we introduce the numerical tools that have been developed to model the ionization in the hydrodynamic simulations with turbulence performed with the HERACLES code. Thanks to the simulations, we present a new model for the formation of pillars based on the curvature and collapse of the dense shell on itself and a new model for the formations of cometary globules based on the turbulence of the cold gas. Several diagnostics have been developed to test these new models in the observations. If pillars are formed by the collapse of the dense shell on itself, the velocity spectrum of a nascent pillar presents a large spectra with a red-shifted and a blue-shifted components that are caused by the foreground and background parts of the shell that collapse along the line of sight. If cometary globules emerge because of the turbulence of the molecular cloud, the velocity spectrum of these globules is shifted at different velocities than the velocity of the shell, pillars and clumps that follow the global expansion of the H ii region. An other diagnostic is the impact of the compression on the probability density function (PDF) of the cold gas. The distribution is double peaked when the turbulent ram pressure is low compared to the ionized-gas pressure. This is the signature of the compression caused by the expansion of the ionized bubble. When the turbulence is high, the two peaks merge and the compression can still be identified although the signature is less clear. We have used Herschel column density maps and molecular-line data to characterize the density and velocity structures of the interface between the ionized and the cold gas in several regions: RCW 120, RCW 36, Cygnus X, the Rosette and Eagle Nebulae. In addition to the diagnostics derived from the simulations, analytical predictions of the shell and pillar parameters was tested and confronted to the observations. In all the regions, we have seen that there is a good agreement with the analytical models and with the simulation diagnostics. The velocity structure of a nascent pillar in the Rosette Nebula suggests that it has been formed by the collapse of the shell on itself and the bulk velocity of cometary globules in Cygnus X and in the Rosette Nebula tends to confirm their turbulent origin. The compression caused by the ionized gas can be seen on the PDF of the cold gas in most of the regions studied. This result is important for the link between the IMF and the global prop! erties of the cloud. If the IMF can be derived from the PDF of a cloud, the impact of the massive stars on the PDF has to be taken in account. Furthermore, we present dedicated simulations of RCW 36 that suggest that the dense clumps at the edge of the ionized gas are not pre-existing, it is likely that their formation was triggered by the compression caused by the ionization. Therefore the ionization from the massive stars is a key process that has to be taken into account for the understanding of the IMF. We also present in appendix other works that have been done in parallel of this thesis: the charge exchange in colliding planetary and stellar winds in collaboration with Prof. E. Chiang during the ISIMA summer school 2011 in Beijing; and the sub-millimeter site testing at the Concordia station in Antarctica with the CAMISTIC team.

Simultaneous detection of multiple biomarkers by means of SERS on polymer nanopillar gold arrays

NASA Astrophysics Data System (ADS)

Morasso, Carlo; Picciolini, Silvia; Mehn, Dora; Pellacani, Paola; Frangolho, Ana; Marchesini, Gerardo; Vanna, Renzo; Gualerzi, Alice; Bedoni, Marzia; Marabelli, Franco; Gramatica, Furio

2016-03-01

The detection of biomarkers by means of Surface Enhanced Raman Spectroscopy (SERS) is foreseen to became a very important tool in the clinical practice because of its excellent sensitivity and potential for the simultaneous detection of multiple biomarkers. In the present paper we describe how it was possible to build a sensor for the detection of genetic biomarkers involved in acute myeloid leukemia. The assay is based on the use of a specifically designed SERS substrate made of a 2D crystal structure of polymeric pillars embedded in a gold layer. This substrate is characterized by good enhancing properties coupled with an excellent homogeneity. The SERS substrate was conjugated with DNA probes complementary to a target sequence and used in a sandwich assay with gold nanoparticles labeled with a second DNA probe and a Raman reporter. The so developed assay allowed the detection of a leukemia biomarker (WT1 gene) and an housekeeping gene with low picomolar sensitivity. At last, we optimized the assay in order to tackle one of the main limitations of SERS based assay: the loss of signal that is observed when the Raman spectra are collected in liquid. Combining a preferential functionalization on the polymeric pillars with a different height of the polymer pillars from the gold layer the assay demonstrated its effectiveness even when measured in buffer.

Graphene-based porous materials with tunable surface area and CO2 adsorption properties synthesized by fluorine displacement reaction with various diamines.

PubMed

Li, Baoyin; Fan, Kun; Ma, Xin; Liu, Yang; Chen, Teng; Cheng, Zheng; Wang, Xu; Jiang, Jiaxing; Liu, Xiangyang

2016-09-15

A mild, operationally simple and controllable protocol for preparing graphene-based porous materials is essential to achieve a good pore-design development. In this paper, graphene-based porous materials with tunable surface area were constructed by the intercalation of fluorinated graphene (FG) based on the reaction of reactive CF bonds attached to graphene sheets with various amine-terminated molecules. In the porous materials, graphene sheets are like building blocks, and the diamines covalently grafted onto graphene framework act as pillars. Various diamines are successfully grafted onto graphene sheets, but the grafting ratio of diamines and reduction degree of FG differ greatly and depend on the chemical reactivity of diamines. Pillared diamine molecules chemically anchor at one end and are capable of undergoing a different reaction on the other end, resulting in three different conformations of graphene derivatives. Nitrogen sorption isotherms revealed that the surface area and pore distribution of the obtained porous materials depend heavily on the size and structure of diamine pillars. CO2 uptake capacity characterization showed that ethylenediamine intercalated FG achieved a high CO2 uptake density of 18.0 CO2 molecules per nm(2) at 0°C and 1.1bars, and high adsorption heat, up to 46.1kJmol(-1) at zero coverage. Copyright © 2016 Elsevier Inc. All rights reserved.

Ionization-induced star formation - IV. Triggering in bound clusters

NASA Astrophysics Data System (ADS)

Dale, J. E.; Ercolano, B.; Bonnell, I. A.

2012-12-01

We present a detailed study of star formation occurring in bound star-forming clouds under the influence of internal ionizing feedback from massive stars across a spectrum of cloud properties. We infer which objects are triggered by comparing our feedback simulations with control simulations in which no feedback was present. We find that feedback always results in a lower star formation efficiency and usually but not always results in a larger number of stars or clusters. Cluster mass functions are not strongly affected by feedback, but stellar mass functions are biased towards lower masses. Ionization also affects the geometrical distribution of stars in ways that are robust against projection effects, but may make the stellar associations more or less subclustered depending on the background cloud environment. We observe a prominent pillar in one simulation which is the remains of an accretion flow feeding the central ionizing cluster of its host cloud and suggest that this may be a general formation mechanism for pillars such as those observed in M16. We find that the association of stars with structures in the gas such as shells or pillars is a good but by no means foolproof indication that those stars have been triggered and we conclude overall that it is very difficult to deduce which objects have been induced to form and which formed spontaneously simply from observing the system at a single time.

Photonic Choke-Joints for Dual Polarization Waveguides

NASA Technical Reports Server (NTRS)

Wollack, Edward J. (Inventor); U-Yen, Kongpop (Inventor); Chuss, David T. (Inventor)

2014-01-01

A waveguide structure for a dual polarization waveguide includes a first flange member, a second flange member, and a waveguide member disposed in each of the first flange member and second flange member. The first flange member and the second flange member are configured to be coupled together in a spaced-apart relationship separated by a gap. The first flange member has a substantially smooth surface, and the second flange member has an array of two-dimensional pillar structures formed therein.

Optimal baseplate rotational alignment for locking-screw fixation in reverse total shoulder arthroplasty: a three-dimensional computer-aided design study.

PubMed

Stephens, Byron F; Hebert, Casey T; Azar, Frederick M; Mihalko, William M; Throckmorton, Thomas W

2015-09-01

Baseplate loosening in reverse total shoulder arthroplasty (RTSA) remains a concern. Placing peripheral screws into the 3 pillars of the densest scapular bone is believed to optimize baseplate fixation. Using a 3-dimensional computer-aided design (3D CAD) program, we investigated the optimal rotational baseplate alignment to maximize peripheral locking-screw purchase. Seventy-three arthritic scapulae were reconstructed from computed tomography images and imported into a 3D CAD software program along with representations of an RTSA baseplate that uses 4 fixed-angle peripheral locking screws. The baseplate position was standardized, and the baseplate was rotated to maximize individual and combined peripheral locking-screw purchase in each of the 3 scapular pillars. The mean ± standard error of the mean positions for optimal individual peripheral locking-screw placement (referenced in internal rotation) were 6° ± 2° for the coracoid pillar, 198° ± 2° for the inferior pillar, and 295° ± 3° for the scapular spine pillar. Of note, 78% (57 of 73) of the screws attempting to obtain purchase in the scapular spine pillar could not be placed without an in-out-in configuration. In contrast, 100% of coracoid and 99% of inferior pillar screws achieved full purchase. The position of combined maximal fixation was 11° ± 1°. These results suggest that approximately 11° of internal rotation is the ideal baseplate position for maximal peripheral locking-screw fixation in RTSA. In addition, these results highlight the difficulty in obtaining optimal purchase in the scapular spine. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Cell motility regulation on a stepped micro pillar array device (SMPAD) with a discrete stiffness gradient.

PubMed

Lee, Sujin; Hong, Juhee; Lee, Junghoon

2016-02-28

Our tissues consist of individual cells that respond to the elasticity of their environment, which varies between and within tissues. To better understand mechanically driven cell migration, it is necessary to manipulate the stiffness gradient across a substrate. Here, we have demonstrated a new variant of the microfabricated polymeric pillar array platform that can decouple the stiffness gradient from the ECM protein area. This goal is achieved via a "stepped" micro pillar array device (SMPAD) in which the contact area with the cell was kept constant while the diameter of the pillar bodies was altered to attain the proper mechanical stiffness. Using double-step SU-8 mold fabrication, the diameter of the top of every pillar was kept uniform, whereas that of the bottom was changed, to achieve the desired substrate rigidity. Fibronectin was immobilized on the pillar tops, providing a focal adhesion site for cells. C2C12, HeLa and NIH3T3 cells were cultured on the SMPAD, and the motion of the cells was observed by time-lapse microscopy. Using this simple platform, which produces a purely physical stimulus, we observed that various types of cell behavior are affected by the mechanical stimulus of the environment. We also demonstrated directed cell migration guided by a discrete rigidity gradient by varying stiffness. Interestingly, cell velocity was highest at the highest stiffness. Our approach enables the regulation of the mechanical properties of the polymeric pillar array device and eliminates the effects of the size of the contact area. This technique is a unique tool for studying cellular motion and behavior relative to various stiffness gradients in the environment.

Aluminium - Cobalt-Pillared Clay for Dye Filtration Membrane

NASA Astrophysics Data System (ADS)

Darmawan, A.; Widiarsih

2018-04-01

The manufacture of membrane support from cobalt aluminium pillared clay has been conducted. This research was conducted by mixing a clay suspension with pillared solution prepared from the mixture of Co(NO3)2.6H2O and AlCl3.6H2O. The molar ratio between Al and Co was 75:25 and the ratio of [OH-]/[metal] was 2. The clay suspension was stirred for 24 hours at room temperature, filtered and dried. The dried clay was then calcined at 200°C, 300°C and 400°C with a ramp rate of 2°C/min. Aluminium-cobalt-pillared clay was then characterized by XRD and GSA and moulded become a membrane support for subsequent tests on dye filtration. The XRD analysis showed that basal spacing (d 001) value of aluminium cobalt was 19.49 Å, which was higher than the natural clay of 15.08Å however, the basal spacing decreased with increasing calcination temperature. The result of the GSA analysis showed that the pore diameter of the aluminium cobalt pillared clay membrane was almost the same as that of natural clay that were 34.5Å and 34.2Å, respectively. Nevertheless, the pillared clay has a more uniform pore size distribution. The results of methylene blue filtration measurements demonstrated that the membrane filter support could well which shown by a clear filtrate at all concentrations tested. The value of rejection and flux decreased with the increasing concentration of methylene blue. The values of dye rejection and water flux reached 99.89% and 5. 80 x 10-6 kg min-1, respectively but they decreased with increasing concentration of methylene blue. The results of this study indicates that the aluminium-pillared clay cobalt could be used as membrane materials especially for ultrafiltration.

Al13-pillared anatase TiO2 as a cathode for a lithium battery

NASA Astrophysics Data System (ADS)

Sun, X. D.; Ma, C. L.; Wang, Y. D.; Li, H. D.

2004-11-01

Al13-pillared anatase TiO2 is used as a cathode of a lithium battery for the first time. First, a layered titanium dioxide with cationic surfactant ions of cetyltrimethylammonium (CTA+) in the interlayers is synthesized by self-assembly. Then, pillared TiO2 is obtained by exchange of polyoxo cations of aluminium, [Al13O4(OH)24(H2O)12]7+, with CTA+ and subsequent calcination at 300 °C for 1 h in the air. Powder x-ray diffraction (XRD), transmission electron microscopy (TEM) and surface area (BET) methods are used to characterize the layered and pillared forms of titanium dioxide. A lithium battery with the Al13-pillared TiO2 as the cathode and Li metal foil as the anode is studied within the 1-2.2 V voltage range. The specific capacity of the closed button cell (size 2025) that is delivered on the initial discharge reached 191.4 mA h g-1 at the rate of 25 mA g-1. The cell shows good cycling performance over 50 cycles.

Nanoscale pillar arrays for separations

DOE PAGES

Kirchner, Teresa; Strickhouser, Rachel; Hatab, Nahla; ...

2015-04-01

The work presented herein evaluates silicon nano-pillar arrays for use in planar chromatography. Electron beam lithography and metal thermal dewetting protocols were used to create nano-thin layer chromatography platforms. With these fabrication methods we are able to reduce the size of the characteristic features in a separation medium below that used in ultra-thin layer chromatography; i.e. pillar heights are 1-2μm and pillar diameters are typically in the 200- 400nm range. In addition to the intrinsic nanoscale aspects of the systems, it is shown they can be further functionalized with nanoporous layers and traditional stationary phases for chromatography; hence exhibit broad-rangingmore » lab-on-a-chip and point-of-care potential. Because of an inherent high permeability and very small effective mass transfer distance between pillars, chromatographic efficiency can be very high but is enhanced herein by stacking during development and focusing while drying, yielding plate heights in the nm range separated band volumes. Practical separations of fluorescent dyes, fluorescently derivatized amines, and anti-tumor drugs are illustrated.« less

Method of underground mining by pillar extraction

DOEpatents

Bowen, Ray J.; Bowen, William R.

1980-08-12

A method of sublevel caving and pillar and top coal extraction for mining thick coal seams includes the advance mining of rooms and crosscuts along the bottom of a seam to a height of about eight feet, and the retreat mining of the top coal from the rooms, crosscuts and portions of the pillars remaining from formation of the rooms and cross-cuts. In the retreat mining, a pocket is formed in a pillar, the top coal above the pocket is drilled, charged and shot, and then the fallen coal is loaded by a continuous miner so that the operator remains under a roof which has not been shot. The top coal from that portion of the room adjacent the pocket is then mined, and another pocket is formed in the pillar. The top coal above the second pocket is mined followed by the mining of the top coal of that portion of the room adjacent the second pocket, all by use of a continuous miner which allows the operator to remain under a roof portion which has not been shot.

Stress concentration in periodically rough Hertzian contact: Hertz to soft-flat-punch transition

PubMed Central

Raphaël, E.; Léger, L.; Restagno, F.; Poulard, C.

2016-01-01

We report on the elastic contact between a spherical lens and a patterned substrate, composed of a hexagonal lattice of cylindrical pillars. The stress field and the size of the contact area are obtained by means of numerical methods: a superposition method of discrete pressure elements and an iterative bisection-like method. For small indentations, a transition from a Hertzian to a soft-flat-punch behaviour is observed when the surface fraction of the substrate that is covered by the pillars is increased. In particular, we present a master curve defined by two dimensionless parameters, which allows one to predict the stress at the centre of the contact region in terms of the surface fraction occupied by pillars. The transition between the limiting contact regimes, Hertzian and soft-flat-punch, is well described by a rational function. Additionally, a simple model to describe the Boussinesq–Cerruti-like contact between the lens and a single elastic pillar, which takes into account the pillar geometry and the elastic properties of the two bodies, is presented. PMID:27713659

USHPRR FUEL FABRICATION PILLAR: FABRICATION STATUS, PROCESS OPTIMIZATIONS, AND FUTURE PLANS

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

Wight, Jared M.; Joshi, Vineet V.; Lavender, Curt A.

The Fuel Fabrication (FF) Pillar, a project within the U.S. High Performance Research Reactor Conversion program of the National Nuclear Security Administration’s Office of Material Management and Minimization, is tasked with the scale-up and commercialization of high-density monolithic U-Mo fuel for the conversion of appropriate research reactors to use of low-enriched fuel. The FF Pillar has made significant steps to demonstrate and optimize the baseline co-rolling process using commercial-scale equipment at both the Y-12 National Security Complex (Y-12) and BWX Technologies (BWXT). These demonstrations include the fabrication of the next irradiation experiment, Mini-Plate 1 (MP-1), and casting optimizations at Y-12.more » The FF Pillar uses a detailed process flow diagram to identify potential gaps in processing knowledge or demonstration, which helps direct the strategic research agenda of the FF Pillar. This paper describes the significant progress made toward understanding the fuel characteristics, and models developed to make informed decisions, increase process yield, and decrease lifecycle waste and costs.« less

Lamellar zirconium phosphates to host metals for catalytic purposes.

PubMed

Ballesteros-Plata, Daniel; Infantes-Molina, Antonia; Rodríguez-Aguado, Elena; Braos-García, Pilar; Rodríguez-Castellón, Enrique

2018-02-27

In the present study a porous lamellar zirconium phosphate heterostructure (PPH) formed from zirconium(iv) phosphate expanded with silica galleries (P/Zr molar ratio equal to 2 and (Si + Zr)/P equal to 3) was prepared to host noble metals. Textural and structural characterization of PPH-noble metal materials was carried out in order to elucidate the location and dispersion of the metallic particles and the properties of the resulting material to be used in catalytic processes. In the present paper, their activity in the catalytic hydrodeoxygenation (HDO) reaction of dibenzofuran (DBF) was evaluated. X-ray diffraction (XRD), solid state nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) evidenced that the structure of the pillared zirconium phosphate material was not modified by the incorporation of Pt and Pd. Moreover, transmission electron microscopy (TEM) showed a different dispersion of the noble metal. The acidity of the resulting PPH-noble metal materials also changed, although in all cases the acidity was of weak nature, and the incorporation of noble metals affected Brønsted acid sites as observed from 31 P NMR spectra. In general, the textural, structural and acidic properties of the resulting materials suggest that PPH can be considered a good candidate to be used as a catalytic support. Thus, the catalytic results of the PPH-noble metal samples indicated that the Pd sample showed a stable behavior probably ascribed to a high dispersion of the active phase. However, the Pt sample suffered from fast deactivation. The selectivity to the reaction products was strongly dependent on the noble metal employed.

Metachronal wave of artificial cilia array actuated by applied magnetic field

NASA Astrophysics Data System (ADS)

Tsumori, Fujio; Marume, Ryuma; Saijou, Akinori; Kudo, Kentaro; Osada, Toshiko; Miura, Hideshi

2016-06-01

In this paper, a biomimetic microstructure related to cilia, which are effective fluidic and conveying systems in nature, is described. Authors have already reported that a magnetic elastomer pillar actuated by a rotating magnetic field can work like a natural cilium. In the present work, we show examples of a cilia array with a metachronal wave as the next step. A metachronal wave is a sequential action of a number of cilia. It is theoretically known that a metachronal wave gives a higher fluidic efficiency; however, there has been no report on a metachronal wave by artificial cilia. We prepared magnetic elastomer pillars that contain chainlike clusters of magnetic particles. The orientation of chains was set to be different in each pillar so that each pillar will deform with a different phase.

Development of a direct three-dimensional biomicrofabrication concept based on electrospraying a custom made siloxane sol

PubMed Central

Sullivan, Alice C.; Jayasinghe, Suwan N.

2007-01-01

We demonstrate here the discovery of a unique and direct three-dimensional biomicrofabrication concept possessing the ability to revolutionize the jet-based fabrication arena. Previous work carried out on similar jet-based approaches have been successful in fabricating only vertical wall∕pillar-structures by the controlled deposition of stacked droplets. However, these advanced jet-techniques have not been able to directly fabricate self-supporting arches∕links (without molds or reaction methods) between adjacent structures (walls or pillars). Our work reported here gives birth to a unique type of jet determined by high intensity electric fields, which is derived from a specially formulated siloxane sol. The sol studied here has been chosen for its attractive properties (such as an excellent cross-linking nature as well as the ability to polymerize via polycondensation on deposition to its biocompatability), which promotes direct forming of biostructures with nanometer (<50 nm) sized droplets in three dimensions. We foresee that this direct three-dimensional biomicrofabrication jet technique coupled with a variety of formulated sols having focused and enhanced functionality will be explored throughout the physical and life sciences. PMID:19693359

Surface Nanostructures Formed by Phase Separation of Metal Salt-Polymer Nanocomposite Film for Anti-reflection and Super-hydrophobic Applications

NASA Astrophysics Data System (ADS)

Con, Celal; Cui, Bo

2017-12-01

This paper describes a simple and low-cost fabrication method for multi-functional nanostructures with outstanding anti-reflective and super-hydrophobic properties. Our method employed phase separation of a metal salt-polymer nanocomposite film that leads to nanoisland formation after etching away the polymer matrix, and the metal salt island can then be utilized as a hard mask for dry etching the substrate or sublayer. Compared to many other methods for patterning metallic hard mask structures, such as the popular lift-off method, our approach involves only spin coating and thermal annealing, thus is more cost-efficient. Metal salts including aluminum nitrate nonahydrate (ANN) and chromium nitrate nonahydrate (CNN) can both be used, and high aspect ratio (1:30) and high-resolution (sub-50 nm) pillars etched into silicon can be achieved readily. With further control of the etching profile by adjusting the dry etching parameters, cone-like silicon structure with reflectivity in the visible region down to a remarkably low value of 2% was achieved. Lastly, by coating a hydrophobic surfactant layer, the pillar array demonstrated a super-hydrophobic property with an exceptionally high water contact angle of up to 165.7°.

Surface Nanostructures Formed by Phase Separation of Metal Salt-Polymer Nanocomposite Film for Anti-reflection and Super-hydrophobic Applications.

PubMed

Con, Celal; Cui, Bo

2017-12-16

This paper describes a simple and low-cost fabrication method for multi-functional nanostructures with outstanding anti-reflective and super-hydrophobic properties. Our method employed phase separation of a metal salt-polymer nanocomposite film that leads to nanoisland formation after etching away the polymer matrix, and the metal salt island can then be utilized as a hard mask for dry etching the substrate or sublayer. Compared to many other methods for patterning metallic hard mask structures, such as the popular lift-off method, our approach involves only spin coating and thermal annealing, thus is more cost-efficient. Metal salts including aluminum nitrate nonahydrate (ANN) and chromium nitrate nonahydrate (CNN) can both be used, and high aspect ratio (1:30) and high-resolution (sub-50 nm) pillars etched into silicon can be achieved readily. With further control of the etching profile by adjusting the dry etching parameters, cone-like silicon structure with reflectivity in the visible region down to a remarkably low value of 2% was achieved. Lastly, by coating a hydrophobic surfactant layer, the pillar array demonstrated a super-hydrophobic property with an exceptionally high water contact angle of up to 165.7°.

Nanoscale Origins of the Size Effect in the Compression Response of Single Crystal Ni-Base Superalloy Micro-Pillars

PubMed Central

Ying, Siqi; Ma, Lifeng; Papadaki, Chrysanthi; Romano Brandt, Leon; Zhang, Hongjia

2018-01-01

Nickel superalloys play a pivotal role in enabling power-generation devices on land, sea, and in the air. They derive their strength from coherent cuboidal precipitates of the ordered γ’ phase that is different from the γ matrix in composition, structure and properties. In order to reveal the correlation between elemental distribution, dislocation glide and the plastic deformation of micro- and nano-sized volumes of a nickel superalloy, a combined in situ nanoindentation compression study was carried out with a scanning electron microscope (SEM) on micro- and nano-pillars fabricated by focused ion beam (FIB) milling of Ni-base superalloy CMSX4. The observed mechanical response (hardening followed by softening) was correlated with the progression of crystal slip that was revealed using FIB nano-tomography and energy-dispersive spectroscopy (EDS) elemental mapping. A hypothesis was put forward that the dependence of material strength on the size of the sample (micropillar diameter) is correlated with the characteristic dimension of the structural units (γ’ precipitates). By proposing two new dislocation-based models, the results were found to be described well by a new parameter-free Hall–Petch equation. PMID:29621189

A 3D metal-organic framework with a pcu net constructed from lead(II) and thiophene-2, 5-dicarboxylic acid: Synthesis, structure and ferroelectric property

NASA Astrophysics Data System (ADS)

Lin, Jian-Di; Rong, Cheng; Lv, Ri-Xin; Wang, Zu-Jian; Long, Xi-Fa; Guo, Guo-Cong; Pan, Chun-Yang

2018-01-01

Self-assembly reaction of Pb(NO3)2 with thiophene-2, 5-dicarboxylic acid (H2TDC) led to an acentric three-dimensional (3D) metal-organic framework under solvothermal conditions, namely, Pb(TDC) (1). The 3D framework of 1 is a pillared-layer structure with the I2O1 type which is composed of a 2D inorganic Pb-O-Pb substructural layer and two independent μ6-TDC2- anions pillars. This 3D framework shows a six-connected pcu topological net according to the topological analysis. Compound 1 crystallizes in an acentric space group and displays potential ferroelectric property which could be due to the swing of the thiophene rings. The remnant polarization (Pr), coercive field (Ec) and saturation spontaneous polarization (Ps) of 1 are ca. 0.034 μC cm-2, 15.7 kV cm-1 and 0.0997 μC cm-2, respectively. Among the H2TDC-based MOFs, the present compound is the first example which shows ferroelectric property. In addition, 1 also exhibits photoluminescent property which can be attributed to ligand-to-metal charge transfer.

Leveraging Strength: The Pillars of American Grand Strategy in World War II

DTIC Science & Technology

2011-01-01

Leveraging Strength: The Pillars of American Grand Strategy in World War II by Tami Davis Biddle Tami Davis Biddle is the Hoyt S. Vandenberg Chair of... world . The war was a transforming event for American society: the course of the war , and the consequences of it, set the conditions for the powerful...Pillars of American Grand Strategy in World War II 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

Understanding the mechanism of nanotube synthesis for controlled production of specific (n,m) structures

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

Resasco, Daniel E.

2010-02-11

This report shows the extensive research on the mechanism responsible for the formation of single walled carbon nanotubes in order to get control over their structural parameters (diameter and chirality). Catalyst formulations, pre-treatment conditions, and reaction conditions are described in detail as well as mechanisms to produce nanotubes structures of specific arrays (vertical forest, nanotube pillars). Applications of SWNT in different fields are also described in this report. In relation to this project five students have graduated (3 PhD and 2 MS) and 35 papers have been published.

Numerical simulation of crosstalk in reduced pitch HgCdTe photon-trapping structure pixel arrays.

PubMed

Schuster, Jonathan; Bellotti, Enrico

2013-06-17

We have investigated crosstalk in HgCdTe photovoltaic pixel arrays employing a photon trapping (PT) structure realized with a periodic array of pillars intended to provide broadband operation. We have found that, compared to non-PT pixel arrays with similar geometry, the array employing the PT structure has a slightly higher optical crosstalk. However, when the total crosstalk is evaluated, the presence of the PT region drastically reduces the total crosstalk; making the use of the PT structure not only useful to obtain broadband operation, but also desirable for reducing crosstalk in small pitch detector arrays.

Titanium based flat heat pipes for computer chip cooling

NASA Astrophysics Data System (ADS)

Soni, Gaurav; Ding, Changsong; Sigurdson, Marin; Bozorgi, Payam; Piorek, Brian; MacDonald, Noel; Meinhart, Carl

2008-11-01

We are developing a highly conductive flat heat pipe (called Thermal Ground Plane or TGP) for cooling computer chips. Conventional heat pipes have circular cross sections and thus can't make good contact with chip surface. The flatness of our TGP will enable conformal contact with the chip surface and thus enhance cooling efficiency. Another limiting factor in conventional heat pipes is the capillary flow of the working fluid through a wick structure. In order to overcome this limitation we have created a highly porous wick structure on a flat titanium substrate by using micro fabrication technology. We first etch titanium to create very tall micro pillars with a diameter of 5 μm, a height of 40 μm and a pitch of 10 μm. We then grow a very fine nano structured titania (NST) hairs on all surfaces of the pillars by oxidation in H202. In this way we achieve a wick structure which utilizes multiple length scales to yield high performance wicking of water. It's capable of wicking water at an average velocity of 1 cm/s over a distance of several cm. A titanium cavity is laser-welded onto the wicking substrate and a small quantity of water is hermetically sealed inside the cavity to achieve a TGP. The thermal conductivity of our preliminary TGP was measured to be 350 W/m-K, but has the potential to be several orders of magnitude higher.

Superhydrophobic Analyte Concentration Utilizing Colloid-Pillar Array SERS Substrates

DOE PAGES

Wallace, Ryan A.; Charlton, Jennifer J.; Kirchner, Teresa B.; ...

2014-11-04

In order to detect a few molecules present in a large sample it is important to know the trace components in the medicinal and environmental sample. Surface enhanced Raman spectroscopy (SERS) is a technique that can be utilized to detect molecules at very low absolute numbers. However, detection at trace concentration levels in real samples requires properly designed delivery and detection systems. Moreover, the following work involves superhydrophobic surfaces that includes silicon pillar arrays formed by lithographic and dewetting protocols. In order to generate the necessary plasmonic substrate for SERS detection, simple and flow stable Ag colloid was added tomore » the functionalized pillar array system via soaking. The pillars are used native and with hydrophobic modification. The pillars provide a means to concentrate analyte via superhydrophobic droplet evaporation effects. A 100-fold concentration of analyte was estimated, with a limit of detection of 2.9 10-12 M for mitoxantrone dihydrochloride. Additionally, analytes were delivered to the surface via a multiplex approach in order to demonstrate an ability to control droplet size and placement for scaled-up applications in real world applications. Finally, a concentration process involving transport and sequestration based on surface treatment selective wicking is demonstrated.« less

First Observations of the Magnetic Field inside the Pillars of Creation: Results from the BISTRO Survey

NASA Astrophysics Data System (ADS)

Pattle, Kate; Ward-Thompson, Derek; Hasegawa, Tetsuo; Bastien, Pierre; Kwon, Woojin; Lai, Shih-Ping; Qiu, Keping; Furuya, Ray; Berry, David; JCMT BISTRO Survey Team

2018-06-01

We present the first high-resolution, submillimeter-wavelength polarimetric observations of—and thus direct observations of the magnetic field morphology within—the dense gas of the Pillars of Creation in M16. These 850 μm observations, taken as part of the B-Fields in Star-forming Region Observations Survey (BISTRO) using the POL-2 polarimeter on the Submillimeter Common-User Bolometer Array 2 (SCUBA-2) camera on the James Clerk Maxwell Telescope (JCMT), show that the magnetic field runs along the length of the Pillars, perpendicular to and decoupled from the field in the surrounding photoionized cloud. Using the Chandrasekhar–Fermi method we estimate a plane-of-sky magnetic field strength of 170–320 μG in the Pillars, consistent with their having been formed through the compression of gas with initially weak magnetization. The observed magnetic field strength and morphology suggests that the magnetic field may be slowing the Pillars’ evolution into cometary globules. We thus hypothesize that the evolution and lifetime of the Pillars may be strongly influenced by the strength of the coupling of their magnetic field to that of their parent photoionized cloud—i.e., that the Pillars’ longevity results from magnetic support.

Improving wettability of photo-resistive film surface with plasma surface modification for coplanar copper pillar plating of IC substrates

NASA Astrophysics Data System (ADS)

Xiang, Jing; Wang, Chong; Chen, Yuanming; Wang, Shouxu; Hong, Yan; Zhang, Huaiwu; Gong, Lijun; He, Wei

2017-07-01

The wettability of the photo-resistive film (PF) surfaces undergoing different pretreatments including the O2sbnd CF4 low-pressure plasma (OCLP) and air plasma (AP), is investigated by water contact angle measurement instrument (WCAMI) before the bottom-up copper pillar plating. Chemical groups analysis performed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) and X-ray photoelectron spectra (XPS) shows that after the OCLP and wash treatment, the wettability of PF surface is attenuated, because embedded fluorine and decreased oxygen content both enhance hydrophobicity. Compared with OCLP treatment, the PF surface treatment by non-toxic air plasma displays features of Csbnd O, Osbnd Cdbnd O, Cdbnd O and sbnd NO2 by AIR-FTIR and XPS, and a promoted wettability by WCAM. Under the identical electroplating condition, the surface with a better wettability allows electrolyte to spontaneously soak all the places of vias, resulting in improved copper pillar uniformity. Statistical analysis of metallographic data shows that more coplanar and flat copper pillars are achieved with the PF treatment of air plasma. Such modified copper-pillar-plating technology meets the requirement of accurate impedance, the high density interconnection for IC substrates.

Superhydrophobic Analyte Concentration Utilizing Colloid-Pillar Array SERS Substrates

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

Wallace, Ryan A.; Charlton, Jennifer J.; Kirchner, Teresa B.

In order to detect a few molecules present in a large sample it is important to know the trace components in the medicinal and environmental sample. Surface enhanced Raman spectroscopy (SERS) is a technique that can be utilized to detect molecules at very low absolute numbers. However, detection at trace concentration levels in real samples requires properly designed delivery and detection systems. Moreover, the following work involves superhydrophobic surfaces that includes silicon pillar arrays formed by lithographic and dewetting protocols. In order to generate the necessary plasmonic substrate for SERS detection, simple and flow stable Ag colloid was added tomore » the functionalized pillar array system via soaking. The pillars are used native and with hydrophobic modification. The pillars provide a means to concentrate analyte via superhydrophobic droplet evaporation effects. A 100-fold concentration of analyte was estimated, with a limit of detection of 2.9 10-12 M for mitoxantrone dihydrochloride. Additionally, analytes were delivered to the surface via a multiplex approach in order to demonstrate an ability to control droplet size and placement for scaled-up applications in real world applications. Finally, a concentration process involving transport and sequestration based on surface treatment selective wicking is demonstrated.« less

Space Geodesy, VLBI, and the Fourth Pillar of Geodesy - Spacetime Curvature

NASA Astrophysics Data System (ADS)

Combrinck, Ludwig

2014-12-01

Typically geodesy is described as having ``three pillars'': the variations in Earth's shape, gravity field, and rotation. These pillars form the conceptual and observational basis for the celestial and terrestrial reference frames required for Earth and space observations. However, it is no longer adequate to base the conceptual and observational basis on only three pillars. Spacetime curvature as described by the General Theory of Relativity (GTR) is an integral component of all space geodesy techniques and influences all measurements, techniques, and data reduction. Spacetime curvature is therefore the fourth pillar. It is the measurement of the shape of spacetime and its variations. Due to accuracies of Very Long Baseline Interferometry (VLBI) and optical celestial reference frame measurements reaching the tens of micro-arcsecond level in the near future, it is essential to recognize the impact of spacetime seeing on the accuracy objectives of the Global Geodetic Observing System. Spacetime seeing (resulting from spacetime curvature) is analogous to astronomical seeing (resulting from atmospheric conditions), as all of spacetime is affected by microlensing/weak lensing to some extent as a result of mass (normal baryonic and darkmatter) distribution, placing a limit on the realization of the celestial reference frame.

21cm Absorption Line Zeeman Observations And Modeling Of Physical Conditions In M16

NASA Astrophysics Data System (ADS)

Kiuchi, Furea; Brogan, C.; Troland, T.

2011-01-01

We present detailed 21 cm HI absorption line observations of M16 using the Very Large Array. The M16 "pillars of creation" are classic examples of the interaction of ISM with radiation from young, hot stars. Magnetic fields can affect these interactions, the 21 cm Zeeman effect reveals magnetic field strengths in the Photodissociation regions associated with the pillars. The present results yield a 3-sigma upper limit upon the line-of-sight magnetic field of about 300 microgauss. This limit is consistent with a total field strength of 500 microgauss, required in the molecular gas if magnetic energies and turbulent energies in the pillars are in equipartition. Most likely, magnetic fields do not play a dominant role in the dynamics of the M16 pillars. Another goal of this study is to determine the distribution of cold HI in the M16 region and to model the physical conditions in the neutral gas in the pillars. We used the spectral synthesis code Cloudy 08.00 for this purpose. We adopted the results of a published Cloudy HII region model and extended this model into the neutral gas to derive physical conditions therein.

Preschool Children's Ideas on Sustainable Development: How Preschool Children Perceive Three Pillars of Sustainability with the Regard to 7R

ERIC Educational Resources Information Center

Kahriman-Ozturk, Deniz; Olgan, Refika; Guler, Tulin

2012-01-01

The purpose of this study is to describe ideas of preschool children about sustainable development. Basic qualitative research was utilized and 36 preschool children enrolled in four different preschools in Ankara were included in the study. Semi-structured interviews were used to obtain data related to ideas of preschool children on three pillars…

Linear spectral response of a Fano-resonant graded-stub filter based on pillar-photonic-crystal waveguides.

PubMed

Tokushima, Masatoshi

2018-02-01

To achieve high spectral linearity, we developed a Fano-resonant graded-stub filter on the basis of a pillar-photonic-crystal (PhC) waveguide. In a numerical simulation, the availability of a linear region within a peak-to-bottom wavelength span was nearly doubled compared to that of a sinusoidal spectrum, which was experimentally demonstrated with a fabricated silicon-pillar PhC stub filter. The high linearity of this filter is suitable for optical modulators used in multilevel amplitude modulation.

From collision to collaboration - Integrating informal recyclers and re-use operators in Europe: A review.

PubMed

Scheinberg, Anne; Nesić, Jelena; Savain, Rachel; Luppi, Pietro; Sinnott, Portia; Petean, Flaviu; Pop, Flaviu

2016-09-01

The European Union hosts some of the world's most developed waste management systems and an ambitious policy commitment to the circular economy. The existence of informal recycling and re-use activities in Europe has been vigorously denied until quite recently, and remains a very challenging subject for the European solid waste management sector, as well as for European government and private institutions. In countries ranging from Malta to Macedonia and from France to Turkey, informal recyclers excluded from legal recycling niches increasingly collide with formalised and controlled European Union approaches to urban waste management, packaging recovery schemes, formal re-use enterprises, and extended producer responsibility systems.This review focuses on the period from 2004 through the first half of 2016. The 78 sources on European (and neighbouring) informal recycling and re-use are contextualised with global sources and experience. The articles focus on informal recovery in and at the borders of the European Union, document the conflicts and collisions, and elaborate some constructive approaches towards legalisation, integration, and reconciliation. The overarching recommendation, to locate the issue of informal recovery and integration in the framework of the European circular economy package, is supported by four specific pillars of an integration strategy: Documentation, legalisation, occupational and enterprise recognition, and preparation for structural integration. © The Author(s) 2016.

Performance evaluation of a cable bolted yield-abutment gate road system at the Crandall Canyon No. 1 Mine, Genwal Resources, Inc., Huntington, Utah

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

Koehler, J.R.; DeMarco, M.J.; Marshall, R.J.

1996-12-01

Although two-entry yield pillar-based gate roads supported by wooden cribs have been commonly used throughout longwalling in the Wasatch Plateau/Roan Cliffs coalfield of central Utah, a three-entry yield-abutment gate road configuration was recently trialed in the Hiawatha Seam at the Genwal Resources (GRI) Crandall Canyon No. 1 Mine, near Huntington, UT. Pillar, entry, and cable bolt performance were monitored through second panel mining using a fairly extensive array of geomechanical instruments installed over a span of four crosscuts. Ground pressure and entry closure measurements confirmed that the 9.1-m-wide (30-ft) yield pillar was partially shielded from first panel longwall loads bymore » the 36.6-m-wide (120-ft) abutment pillar, and consequently, experienced only minor yielding until the approach of the second panel face. Complete yielding of the 9.1-m-wide (30-ft) pillar occurred when the second panel was approximately 6.1 m (20 ft) in by the instrumentation site. Average cable bolt loads and differential roof sag remained low through second panel mining and tailgate entry ground conditions were excellent; however, very high ground pressures in the abutment and yield pillars, and second panel rib strongly suggest a high potential for coal bumps utilizing this gate road configuration at mining cover depths in excess of 396 to 457 m (1300 to 1500 ft). This conclusion is supported by the suspected occurrence of small coal bumps along the abutment pillar ribs, observed indirectly as fresh debris in the middle entry just behind the second face. This paper presents a case history developed from the geotechnical measurements and on-site observations of this unique application of a yield-abutment gate road configuration and cable support system in the Hiawatha Seam.« less

A multiscale simulation technique for molecular electronics: design of a directed self-assembled molecular n-bit shift register memory device.

PubMed

Lambropoulos, Nicholas A; Reimers, Jeffrey R; Crossley, Maxwell J; Hush, Noel S; Silverbrook, Kia

2013-12-20

A general method useful in molecular electronics design is developed that integrates modelling on the nano-scale (using quantum-chemical software) and on the micro-scale (using finite-element methods). It is applied to the design of an n-bit shift register memory that could conceivably be built using accessible technologies. To achieve this, the entire complex structure of the device would be built to atomic precision using feedback-controlled lithography to provide atomic-level control of silicon devices, controlled wet-chemical synthesis of molecular insulating pillars above the silicon, and controlled wet-chemical self-assembly of modular molecular devices to these pillars that connect to external metal electrodes (leads). The shift register consists of n connected cells that read data from an input electrode, pass it sequentially between the cells under the control of two external clock electrodes, and deliver it finally to an output device. The proposed cells are trimeric oligoporphyrin units whose internal states are manipulated to provide functionality, covalently connected to other cells via dipeptide linkages. Signals from the clock electrodes are conveyed by oligoporphyrin molecular wires, and μ-oxo porphyrin insulating columns are used as the supporting pillars. The developed multiscale modelling technique is applied to determine the characteristics of this molecular device, with in particular utilization of the inverted region for molecular electron-transfer processes shown to facilitate latching and control using exceptionally low energy costs per logic operation compared to standard CMOS shift register technology.

A multiscale simulation technique for molecular electronics: design of a directed self-assembled molecular n-bit shift register memory device

NASA Astrophysics Data System (ADS)

Lambropoulos, Nicholas A.; Reimers, Jeffrey R.; Crossley, Maxwell J.; Hush, Noel S.; Silverbrook, Kia

2013-12-01

A general method useful in molecular electronics design is developed that integrates modelling on the nano-scale (using quantum-chemical software) and on the micro-scale (using finite-element methods). It is applied to the design of an n-bit shift register memory that could conceivably be built using accessible technologies. To achieve this, the entire complex structure of the device would be built to atomic precision using feedback-controlled lithography to provide atomic-level control of silicon devices, controlled wet-chemical synthesis of molecular insulating pillars above the silicon, and controlled wet-chemical self-assembly of modular molecular devices to these pillars that connect to external metal electrodes (leads). The shift register consists of n connected cells that read data from an input electrode, pass it sequentially between the cells under the control of two external clock electrodes, and deliver it finally to an output device. The proposed cells are trimeric oligoporphyrin units whose internal states are manipulated to provide functionality, covalently connected to other cells via dipeptide linkages. Signals from the clock electrodes are conveyed by oligoporphyrin molecular wires, and μ-oxo porphyrin insulating columns are used as the supporting pillars. The developed multiscale modelling technique is applied to determine the characteristics of this molecular device, with in particular utilization of the inverted region for molecular electron-transfer processes shown to facilitate latching and control using exceptionally low energy costs per logic operation compared to standard CMOS shift register technology.

Microfabricated discontinuous-edge surface topographies influence osteoblast adhesion, migration, cytoskeletal organization, and proliferation and enhance matrix and mineral deposition in vitro.

PubMed

Hamilton, D W; Wong, K S; Brunette, D M

2006-05-01

The fabrication of surfaces that stimulate increased adhesion, migration, and differentiated function of osteoblasts has been viewed as being desirable for many orthopedic applications. Previous studies have shown that microfabricated pits and grooves alter adhesion, spreading, matrix secretion, and production of mineral by rat calvarial osteoblasts (RCOs). The mechanisms underlying these effects are unknown, although microenvironment and cell alignment are considered to play a role. The aim of this work was to investigate the behavior of RCOs on microfabricated discontinuous-edge surfaces (DESs), which could provide an alternative means to control both the microenvironment and cellular alignment. Two types of discontinuous-type structures were employed, gap-cornered boxes and micron scale pillars. DES gap-cornered boxes and the pillars influenced the arrangement of F-actin, microtubules, and vinculin. Osteoblasts were guided in their direction of migration on both types of substrata. Both box DESs and pillars altered the staining intensity and localization pattern of phosphotyrosine and src-activated FAK localization. Cell multilayering, matrix deposition, and mineralization were enhanced on both discontinuous topographies when compared with smooth controls. This study shows that DESs alter adhesion, migration, and proliferative responses from osteoblasts at early time points (<1 week) and promote multilayering, matrix deposition, and mineral deposition at later times (2-6 weeks). Such topographical patterns could potentially be employed as effective surface features on bone-contacting implants or in membrane-based periodontal applications.

Herschel Sees Through Ghostly Pillars

NASA Image and Video Library

2012-01-18

This image of the Eagle nebula shows the self-emission of the intensely cold nebula gas and dust as never seen before; the nebula intricate tendril nature, with vast cavities forms an almost cave-like surrounding to the famous pillars.

Integrated strain array for cellular mechanobiology studies

NASA Astrophysics Data System (ADS)

Simmons, C. S.; Sim, J. Y.; Baechtold, P.; Gonzalez, A.; Chung, C.; Borghi, N.; Pruitt, B. L.

2011-05-01

We have developed an integrated strain array for cell culture enabling high-throughput mechano-transduction studies. Biocompatible cell culture chambers were integrated with an acrylic pneumatic compartment and microprocessor-based control system. Each element of the array consists of a deformable membrane supported by a cylindrical pillar within a well. For user-prescribed waveforms, the annular region of the deformable membrane is pulled into the well around the pillar under vacuum, causing the pillar-supported region with cultured cells to be stretched biaxially. The optically clear device and pillar-based mechanism of operation enables imaging on standard laboratory microscopes. Straightforward fabrication utilizes off-the-shelf components, soft lithography techniques in polydimethylsiloxane and laser ablation of acrylic sheets. Proof of compatibility with basic biological assays and standard imaging equipment were accomplished by straining C2C12 skeletal myoblasts on the device for 6 h. At higher strains, cells and actin stress fibers realign with a circumferential preference.

Retention in porous layer pillar array planar separation platforms

DOE PAGES

Lincoln, Danielle R.; Lavrik, Nickolay V.; Kravchenko, Ivan I.; ...

2016-08-11

Here, this work presents the retention capabilities and surface area enhancement of highly ordered, high-aspect-ratio, open-platform, two-dimensional (2D) pillar arrays when coated with a thin layer of porous silicon oxide (PSO). Photolithographically prepared pillar arrays were coated with 50–250 nm of PSO via plasma-enhanced chemical vapor deposition and then functionalized with either octadecyltrichlorosilane or n-butyldimethylchlorosilane. Theoretical calculations indicate that a 50 nm layer of PSO increases the surface area of a pillar nearly 120-fold. Retention capabilities were tested by observing capillary-action-driven development under various conditions, as well as by running one-dimensional separations on varying thicknesses of PSO. Increasing the thicknessmore » of PSO on an array clearly resulted in greater retention of the analyte(s) in question in both experiments. In culmination, a two-dimensional separation of fluorescently derivatized amines was performed to further demonstrate the capabilities of these fabricated platforms.« less

Radiation-MHD Simulations of Pillars and Globules in HII Regions

NASA Astrophysics Data System (ADS)

Mackey, J.

2012-07-01

Implicit and explicit raytracing-photoionisation algorithms have been implemented in the author's radiation-magnetohydrodynamics code. The algorithms are described briefly and their efficiency and parallel scaling are investigated. The implicit algorithm is more efficient for calculations where ionisation fronts have very supersonic velocities, and the explicit algorithm is favoured in the opposite limit because of its better parallel scaling. The implicit method is used to investigate the effects of initially uniform magnetic fields on the formation and evolution of dense pillars and cometary globules at the boundaries of HII regions. It is shown that for weak and medium field strengths an initially perpendicular field is swept into alignment with the pillar during its dynamical evolution, matching magnetic field observations of the ‘Pillars of Creation’ in M16. A strong perpendicular magnetic field remains in its initial configuration and also confines the photoevaporation flow into a bar-shaped, dense, ionised ribbon which partially shields the ionisation front.

Retention in porous layer pillar array planar separation platforms

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

Lincoln, Danielle R.; Lavrik, Nickolay V.; Kravchenko, Ivan I.

Here, this work presents the retention capabilities and surface area enhancement of highly ordered, high-aspect-ratio, open-platform, two-dimensional (2D) pillar arrays when coated with a thin layer of porous silicon oxide (PSO). Photolithographically prepared pillar arrays were coated with 50–250 nm of PSO via plasma-enhanced chemical vapor deposition and then functionalized with either octadecyltrichlorosilane or n-butyldimethylchlorosilane. Theoretical calculations indicate that a 50 nm layer of PSO increases the surface area of a pillar nearly 120-fold. Retention capabilities were tested by observing capillary-action-driven development under various conditions, as well as by running one-dimensional separations on varying thicknesses of PSO. Increasing the thicknessmore » of PSO on an array clearly resulted in greater retention of the analyte(s) in question in both experiments. In culmination, a two-dimensional separation of fluorescently derivatized amines was performed to further demonstrate the capabilities of these fabricated platforms.« less

Removal of Ciprofloxacin from Aqueous Solutions Using Pillared Clays

PubMed Central

Roca Jalil, Maria Eugenia; Baschini, Miria; Sapag, Karim

2017-01-01

Emerging contaminants in the environment have caused enormous concern in the last few decades, and among them, antibiotics have received special attention. On the other hand, adsorption has shown to be a useful, low-cost, and eco-friendly method for the removal of this type of contaminants from water. This work is focused on the study of ciprofloxacin (CPX) removal from water by adsorption on pillared clays (PILC) under basic pH conditions, where CPX is in its anionic form (CPX−). Four different materials were synthetized, characterized, and studied as adsorbents of CPX (Al-, Fe-, Si-, and Zr-PILC). The highest CPX adsorption capacities of 100.6 and 122.1 mg g−1 were obtained for the Si- and Fe-PILC (respectively), and can be related to the porous structure of the PILCs. The suggested adsorption mechanism involves inner-sphere complexes formation as well as van der Waals interactions between CPX− and the available adsorption sites on the PILC surfaces. PMID:29168798

History of Hubble Space Telescope (HST)

NASA Image and Video Library

1995-01-01

These eerie, dark, pillar-like structures are actually columns of cool interstellar hydrogen gas and dust that are also incubators for new stars. The pillars protrude from the interior wall of a dark molecular cloud like stalagmites from the floor of a cavern. They are part of the Eagle Nebula (also called M16), a nearby star-forming region 7,000 light-years away, in the constellation Serpens. The ultraviolet light from hot, massive, newborn stars is responsible for illuminating the convoluted surfaces of the columns and the ghostly streamers of gas boiling away from their surfaces, producing the dramatic visual effects that highlight the three-dimensional nature of the clouds. This image was taken on April 1, 1995 with the Hubble Space Telescope Wide Field Planetary Camera 2. The color image is constructed from three separate images taken in the light of emission from different types of atoms. Red shows emissions from singly-ionized sulfur atoms, green shows emissions from hydrogen, and blue shows light emitted by doubly-ionized oxygen atoms.

Sensitive SERS detection at the single-particle level based on nanometer-separated mushroom-shaped plasmonic dimers

NASA Astrophysics Data System (ADS)

Xiang, Quan; Li, Zhiqin; Zheng, Mengjie; Liu, Qing; Chen, Yiqin; Yang, Lan; Jiang, Tian; Duan, Huigao

2018-03-01

Elevated metallic nanostructures with nanogaps (<10 nm) possess advantages for surface enhanced Raman scattering (SERS) via the synergic effects of nanogaps and efficient decoupling from the substrate through an elevated three-dimensional (3D) design. In this work, we demonstrate a pattern-transfer-free process to reliably define elevated nanometer-separated mushroom-shaped dimers directly from 3D resist patterns based on the gap-narrowing effect during the metallic film deposition. By controlling the initial size of nanogaps in resist structures and the following deposited film thickness, metallic nanogaps could be tuned at the sub-10 nm scale with single-digit nanometer precision. Both experimental and simulated results revealed that gold dimer on mushroom-shaped pillars have the capability to achieve higher SERS enhancement factor comparing to those plasmonic dimers on cylindrical pillars or on a common SiO2/Si substrate, implying that the nanometer-gapped elevated dimer is an ideal platform to achieve the highest possible field enhancement for various plasmonic applications.

MOF-Sensitized Solar Cells Enabled by a Pillared Porphyrin Framework

DOE PAGES

Spoerke, Erik D.; Small, Leo J.; Foster, Michael E.; ...

2017-03-01

Metal–organic frameworks (MOFs) are highly ordered, functionally tunable supramolecular materials with the potential to improve dye-sensitized solar cells (DSSCs). Several recent reports have indicated that photocurrent can be generated in Grätzel-type DSSC devices when MOFs are used as the sensitizer. However, the specific role(s) of the incorporated MOFs and the potential influence of residual MOF precursor species on device performance are unclear. Herein, we describe the assembly and characterization of a simplified DSSC platform in which isolated MOF crystals are used as the sensitizer in a planar device architecture. We selected a pillared porphyrin framework (PPF) as the MOF sensitizer,more » taking particular care to avoid contamination from light-absorbing MOF precursors. Photovoltaic and electrochemical characterization under simulated 1-sun and wavelength-selective illumination revealed photocurrent generation that is clearly ascribable to the PPF MOF. In conclusion, continued refinement of highly versatile MOF structure and chemistry holds promise for dramatic improvements in emerging photovoltaic technologies.« less

Conformational Rigidity and Protein Dynamics at Distinct Timescales Regulate PTP1B Activity and Allostery.

PubMed

Choy, Meng S; Li, Yang; Machado, Luciana E S F; Kunze, Micha B A; Connors, Christopher R; Wei, Xingyu; Lindorff-Larsen, Kresten; Page, Rebecca; Peti, Wolfgang

2017-02-16

Protein function originates from a cooperation of structural rigidity, dynamics at different timescales, and allostery. However, how these three pillars of protein function are integrated is still only poorly understood. Here we show how these pillars are connected in Protein Tyrosine Phosphatase 1B (PTP1B), a drug target for diabetes and cancer that catalyzes the dephosphorylation of numerous substrates in essential signaling pathways. By combining new experimental and computational data on WT-PTP1B and ≥10 PTP1B variants in multiple states, we discovered a fundamental and evolutionarily conserved CH/π switch that is critical for positioning the catalytically important WPD loop. Furthermore, our data show that PTP1B uses conformational and dynamic allostery to regulate its activity. This shows that both conformational rigidity and dynamics are essential for controlling protein activity. This connection between rigidity and dynamics at different timescales is likely a hallmark of all enzyme function. Copyright © 2017 Elsevier Inc. All rights reserved.

Carrier confinement effects of InxGa1-xN/GaN multi quantum disks with GaN surface barriers grown in GaN nanorods

NASA Astrophysics Data System (ADS)

Park, Youngsin; Chan, Christopher C. S.; Taylor, Robert A.; Kim, Nammee; Jo, Yongcheol; Lee, Seung W.; Yang, Woochul; Im, Hyunsik

2018-04-01

Structural and optical properties of InxGa1-xN/GaN multi quantum disks (QDisks) grown on GaN nanorods by molecular beam epitaxy have been investigated by transmission electron microscopy and micro-photoluminescence (PL) spectroscopy. Two types of InGaN QDisks were grown: a pseudo-3D confined InGaN pillar-type QDisks embedded in GaN nanorods; and QDisks in flanged cone type GaN nanorods. The PL emission peak and excitation dependent PL behavior of the pillar-type Qdisks differ greatly from those of the flanged cone type QDisks. Time resolved PL was carried out to probe the differences in charge carrier dynamics. The results suggest that by constraining the formation of InGaN QDisks within the centre of the nanorod, carriers are restricted from migrating to the surface, decreasing the surface recombination at high carrier densities.

Tilted pillar array fabrication by the combination of proton beam writing and soft lithography for microfluidic cell capture: Part 1 Design and feasibility.

PubMed

Rajta, Istvan; Huszánk, Robert; Szabó, Atilla T T; Nagy, Gyula U L; Szilasi, Szabolcs; Fürjes, Peter; Holczer, Eszter; Fekete, Zoltan; Járvás, Gabor; Szigeti, Marton; Hajba, Laszlo; Bodnár, Judit; Guttman, Andras

2016-02-01

Design, fabrication, integration, and feasibility test results of a novel microfluidic cell capture device is presented, exploiting the advantages of proton beam writing to make lithographic irradiations under multiple target tilting angles and UV lithography to easily reproduce large area structures. A cell capture device is demonstrated with a unique doubly tilted micropillar array design for cell manipulation in microfluidic applications. Tilting the pillars increased their functional surface, therefore, enhanced fluidic interaction when special bioaffinity coating was used, and improved fluid dynamic behavior regarding cell culture injection. The proposed microstructures were capable to support adequate distribution of body fluids, such as blood, spinal fluid, etc., between the inlet and outlet of the microfluidic sample reservoirs, offering advanced cell capture capability on the functionalized surfaces. The hydrodynamic characteristics of the microfluidic systems were tested with yeast cells (similar size as red blood cells) for efficient capture. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Optofluidic fabrication for 3D-shaped particles

NASA Astrophysics Data System (ADS)

Paulsen, Kevin S.; di Carlo, Dino; Chung, Aram J.

2015-04-01

Complex three-dimensional (3D)-shaped particles could play unique roles in biotechnology, structural mechanics and self-assembly. Current methods of fabricating 3D-shaped particles such as 3D printing, injection moulding or photolithography are limited because of low-resolution, low-throughput or complicated/expensive procedures. Here, we present a novel method called optofluidic fabrication for the generation of complex 3D-shaped polymer particles based on two coupled processes: inertial flow shaping and ultraviolet (UV) light polymerization. Pillars within fluidic platforms are used to deterministically deform photosensitive precursor fluid streams. The channels are then illuminated with patterned UV light to polymerize the photosensitive fluid, creating particles with multi-scale 3D geometries. The fundamental advantages of optofluidic fabrication include high-resolution, multi-scalability, dynamic tunability, simple operation and great potential for bulk fabrication with full automation. Through different combinations of pillar configurations, flow rates and UV light patterns, an infinite set of 3D-shaped particles is available, and a variety are demonstrated.

Immobilization of heavy metals on pillared montmorillonite with a grafted chelate ligand.

PubMed

Brown, Loren; Seaton, Kenneth; Mohseni, Ray; Vasiliev, Aleksey

2013-10-15

The objective of this work was the development of an efficient adsorbent for irreversible immobilization of heavy metals in contaminated soils. The adsorbent was prepared by pillaring of montmorillonite with silica followed by grafting of a chelate ligand on its surface. Obtained adsorbent was mesoporous with high content of adsorption sites. Its structure was studied by BET adsorption of N2, dynamic light scattering, and scanning electron microscopy. The adsorption capacity of the organoclay was measured by its mixing with contaminated kaolin and soil samples and by analysis of heavy metal contents in leachate. Deionized water and 50% acetic acid were used for leaching of metals from the samples. As it was demonstrated by the experiments, the adsorbent was efficient in immobilization of heavy metals not only in neutral aqueous media but also in the presence of weak acid. As a result, the adsorbent can be used for reduction of heavy metal leaching from contaminated sites. Copyright © 2013 Elsevier B.V. All rights reserved.

A novel pillar indentation splitting test for measuring fracture toughness of thin ceramic coatings

DOE PAGES

Sebastiani, Marco; Johanns, K. E.; Herbert, Erik G.; ...

2014-05-16

Fracture toughness is an important material property that plays a role in determining the in-service mechanical performance and adhesion of thin ceramic films. Unfortunately, measuring thin film fracture toughness is affected by influences from the substrate and the large residual stresses that can exist in the films. In this paper, we explore a promising new technique that potentially overcomes these problems based on nanoindentation testing of micro-pillars produced by focused ion beam milling of the films. By making the pillar diameter approximately equal to its length, the residual stress in the pillar’s upper portion is almost fully relaxed, and whenmore » indented with a sharp Berkovich indenter, the pillars fracture by splitting at reproducible loads that are readily quantified by a sudden displacement excursion in the load displacement behavior. Cohesive finite element simulations are used to analyze and develop, for a given material, a simple relation between the critical load at failure, pillar radius, and fracture toughness. The main novel aspect of this work is that neither crack geometries nor crack sizes need to be measured post test. Furthermore, the residual stress can be measured at the same time with toughness, by comparing the indentation results from the stress-free pillars and the as-deposited film. The method is tested on three different hard coatings formed by physical vapor deposition: titanium nitride, chromium nitride, and a CrAlN/Si 3N 4 nanocomposite. Results compare well to independently measured values of fracture toughness for the three brittle films. The technique offers several benefits over existing methods.« less

30 CFR 75.386 - Final mining of pillars.

Code of Federal Regulations, 2010 CFR

2010-07-01

... one mine opening is available due to final mining of pillars, no more than 20 miners at a time shall be allowed in the mine, and the distance between the mine opening and working face shall not exceed...

Detail of concrete pillars and steps leading to main entry ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Detail of concrete pillars and steps leading to main entry at southeast elevation; camera facing west. - Mare Island Naval Shipyard, Hospital Ward, Johnson Lane, west side at intersection of Johnson Lane & Cossey Street, Vallejo, Solano County, CA

Retention of contaminants Cd and Hg adsorbed and intercalated in aluminosilicate clays: A first principles study

NASA Astrophysics Data System (ADS)

Crasto de Lima, F. D.; Miwa, R. H.; Miranda, Caetano R.

2017-11-01

Layered clay materials have been used to incorporate transition metal (TM) contaminants. Based on first-principles calculations, we have examined the energetic stability and the electronic properties due to the incorporation of Cd and Hg in layered clay materials, kaolinite (KAO) and pyrophyllite (PYR). The TM can be (i) adsorbed on the clay surface as well as (ii) intercalated between the clay layers. For the intercalated case, the contaminant incorporation rate can be optimized by controlling the interlayer spacing of the clay, namely, pillared clays. Our total energy results reveal that the incorporation of the TMs can be maximized through a suitable tuning of vertical distance between the clay layers. Based on the calculated TM/clay binding energies and the Langmuir absorption model, we estimate the concentrations of the TMs. Further kinetic properties have been examined by calculating the activation energies, where we found energy barriers of ˜20 and ˜130 meV for adsorbed and intercalated cases, respectively. The adsorption and intercalation of ionized TM adatoms were also considered within the deprotonated KAO surface. This also leads to an optimal interlayer distance which maximizes the TM incorporation rate. By mapping the total charge transfers at the TM/clay interface, we identify a net electronic charge transfer from the TM adatoms to the topmost clay surface layer. The effect of such a charge transfer on the electronic structure of the clay (host) has been examined through a set of X-ray absorption near edge structure (XANES) simulations, characterizing the changes of the XANES spectra upon the presence of the contaminants. Finally, for the pillared clays, we quantify the Cd and Hg K-edge energy shifts of the TMs as a function of the interlayer distance between the clay layers and the Al K-edge spectra for the pristine and pillared clays.

Towering Infernos

NASA Image and Video Library

2005-11-09

This majestic false-color image from NASA's Spitzer Space Telescope shows the "mountains" where stars are born. Dubbed "Mountains of Creation" by Spitzer scientists, these towering pillars of cool gas and dust are illuminated at their tips with light from warm embryonic stars. The new infrared picture is reminiscent of Hubble's iconic visible-light image of the Eagle Nebula, which also features a star-forming region, or nebula, that is being sculpted into pillars by radiation and winds from hot, massive stars. The pillars in the Spitzer image are part of a region called W5, in the Cassiopeia constellation 7,000 light-years away and 50 light-years across. They are more than 10 times in the size of those in the Eagle Nebula (shown to scale here). The Spitzer's view differs from Hubble's because infrared light penetrates dust, whereas visible light is blocked by it. In the Spitzer image, hundreds of forming stars (white/yellow) can seen for the first time inside the central pillar, and dozens inside the tall pillar to the left. Scientists believe these star clusters were triggered into existence by radiation and winds from an "initiator" star more than 10 times the mass of our Sun. This star is not pictured, but the finger-like pillars "point" toward its location above the image frame. The Spitzer picture also reveals stars (blue) a bit older than the ones in the pillar tips in the evacuated areas between the clouds. Scientists believe these stars were born around the same time as the massive initiator star not pictured. A third group of young stars occupies the bright area below the central pillar. It is not known whether these stars formed in a related or separate event. Some of the blue dots are foreground stars that are not members of this nebula. The red color in the Spitzer image represents organic molecules known as polycyclic aromatic hydrocarbons. These building blocks of life are often found in star-forming clouds of gas and dust. Like small dust grains, they are heated by the light from the young stars, then emit energy in infrared wavelengths. This image was taken by the infrared array camera on Spitzer. It is a 4-color composite of infrared light, showing emissions from wavelengths of 3.6 microns (blue), 4.5 microns (green), 5.8 microns (orange), and 8.0 microns (red). http://photojournal.jpl.nasa.gov/catalog/PIA03096

Periods of sensitivity to thyroid hormone during the development of the organ of Corti.

PubMed

Uziel, A

1986-01-01

Cochlear structures are sensitive to the morphogenetic effect of thyroid hormone during the whole duration of maturation. For each structure, there exists a period of maximal sensitivity to thyroid hormone which corresponds to the period of development during which the structure of interest undergoes its main morphological changes (6 to 13 days for the inner sulcus epithelium, 6 to 10 days for the pillars, the 2nd and a part of the 3rd postnatal week for OHCs and their efferent innervation in rats). These periods of sensitivity can be considered as critical periods because cochlear structures are maximally vulnerable to thyroid deficiency during these periods.

Essentials for sustainable urban transport in Brazil's large metropolitan areas.

DOT National Transportation Integrated Search

1996-08-01

This paper describes four main pillars for sound development and long-term sustainability of the urban transport sector in large metropolitan areas, and suggests how they can be introduced. These pillars are: a) a Regional Transport Coordination Comm...

A diabetic retinopathy detection method using an improved pillar K-means algorithm.

PubMed

Gogula, Susmitha Valli; Divakar, Ch; Satyanarayana, Ch; Rao, Allam Appa

2014-01-01

The paper presents a new approach for medical image segmentation. Exudates are a visible sign of diabetic retinopathy that is the major reason of vision loss in patients with diabetes. If the exudates extend into the macular area, blindness may occur. Automated detection of exudates will assist ophthalmologists in early diagnosis. This segmentation process includes a new mechanism for clustering the elements of high-resolution images in order to improve precision and reduce computation time. The system applies K-means clustering to the image segmentation after getting optimized by Pillar algorithm; pillars are constructed in such a way that they can withstand the pressure. Improved pillar algorithm can optimize the K-means clustering for image segmentation in aspects of precision and computation time. This evaluates the proposed approach for image segmentation by comparing with Kmeans and Fuzzy C-means in a medical image. Using this method, identification of dark spot in the retina becomes easier and the proposed algorithm is applied on diabetic retinal images of all stages to identify hard and soft exudates, where the existing pillar K-means is more appropriate for brain MRI images. This proposed system help the doctors to identify the problem in the early stage and can suggest a better drug for preventing further retinal damage.

A novel double patterning approach for 30nm dense holes

NASA Astrophysics Data System (ADS)

Hsu, Dennis Shu-Hao; Wang, Walter; Hsieh, Wei-Hsien; Huang, Chun-Yen; Wu, Wen-Bin; Shih, Chiang-Lin; Shih, Steven

2011-04-01

Double Patterning Technology (DPT) was commonly accepted as the major workhorse beyond water immersion lithography for sub-38nm half-pitch line patterning before the EUV production. For dense hole patterning, classical DPT employs self-aligned spacer deposition and uses the intersection of horizontal and vertical lines to define the desired hole patterns. However, the increase in manufacturing cost and process complexity is tremendous. Several innovative approaches have been proposed and experimented to address the manufacturing and technical challenges. A novel process of double patterned pillars combined image reverse will be proposed for the realization of low cost dense holes in 30nm node DRAM. The nature of pillar formation lithography provides much better optical contrast compared to the counterpart hole patterning with similar CD requirements. By the utilization of a reliable freezing process, double patterned pillars can be readily implemented. A novel image reverse process at the last stage defines the hole patterns with high fidelity. In this paper, several freezing processes for the construction of the double patterned pillars were tested and compared, and 30nm double patterning pillars were demonstrated successfully. A variety of different image reverse processes will be investigated and discussed for their pros and cons. An economic approach with the optimized lithography performance will be proposed for the application of 30nm DRAM node.

Microdevice arrays of high aspect ratio poly(dimethylsiloxane) pillars for the investigation of multicellular tumour spheroid mechanical properties.

PubMed

Aoun, Laurène; Weiss, Pierre; Laborde, Adrian; Ducommun, Bernard; Lobjois, Valérie; Vieu, Christophe

2014-07-07

We report the design, fabrication and evaluation of an array of microdevices composed of high aspect ratio PDMS pillars, dedicated to the study of tumour spheroid mechanical properties. The principle of the microdevice is to confine a spheroid within a circle of micropillars acting as peripheral flexible force sensors. We present a technological process for fabricating high aspect ratio micropillars (300 μm high) with tunable feature dimensions (diameter and spacing) enabling production of flexible PDMS pillars with a height comparable to spheroid sizes. This represents an upscale of 10 along the vertical direction in comparison to more conventional PDMS pillar force sensors devoted to single cell studies, while maintaining their force sensitivity in the same order of magnitude. We present a method for keeping these very high aspect ratio PDMS pillars stable and straight in liquid solution. We demonstrate that microfabricated devices are biocompatible and adapted to long-term spheroid growth. Finally, we show that the spheroid interaction with the micropillars' surface is dependent on PDMS cellular adhesiveness. Time-lapse recordings of growth-induced micropillars' bending coupled with a software program to automatically detect and analyse micropillar displacements are presented. The use of these microdevices as force microsensors opens new prospects in the fields of tissue mechanics and pharmacological drug screening.

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

Chao, Tzu-Ling; Yang, Chen-I., E-mail: ciyang@thu.edu.tw

The preparations and properties of three new homochiral three-dimensional (3D) coordination polymers, [M(D-cam)(pyz)(H{sub 2}O){sub 2}]{sub n} (M=Co (1) and Ni (2); D-H{sub 2}cam=(+) D-camphoric acid; pyz=pyrazine) and [Mn{sub 2}(D-cam){sub 2}(H{sub 2}O){sub 2}] (3), under solvothermal conditions is described. Single-crystal X-ray diffraction analyses revealed that all of compounds are homochiral 3D structure. 1 and 2 are isostructural and crystallize in the trigonal space group P3{sub 2}21, while 3 crystallizes in monoclinic space group P2{sub 1}. The structure of 1 and 2 consists of metal-D-cam helical chains which are pillared with pyrazine ligands into a 3D framework structure and 3 features amore » 3D homochiral framework involving one-dimensional manganese-carboxylate chains that are aligned parallel to the b axis. Magnetic susceptibility data of all compounds were collected. The findings indicate that μ{sub 2}-pyrazine dominate weak antiferromagnetic coupling within 1 and 2, while 3 exhibits antiferromagnetic behavior through the carboxylate groups of D-cam ligand. -- Graphical abstract: The preparations and properties of three new homochiral three-dimensional (3D) coordination polymers, [M(D-cam)(pyz)(H{sub 2}O){sub 2}]{sub n} (M=Co (1) and Ni (2); D-H{sub 2}cam=(+) D-camphoric acid; pyz=pyrazine) and [Mn{sub 2}(D-cam){sub 2}(H{sub 2}O){sub 2}] (3), under solvothermal conditions is described. Single-crystal X-ray diffraction analyses revealed that all of compounds are homochiral 3D structure. 1 and 2 are isostructural and crystallize in the trigonal space group P3{sub 2}21, while 3 crystallizes in monoclinic space group P2{sub 1}. The structure of 1 and 2 consists of metal-D-cam helical chains which are pillared with pyrazine ligands into a 3D framework structure and 3 features a 3D homochiral framework involving one-dimensional manganese-carboxylate chains that are aligned parallel to the b axis. Magnetic susceptibility data of all compounds were collected. The findings indicate that μ{sub 2}-pyrazine dominate weak antiferromagnetic coupling within 1 and 2, while 3 exhibits antiferromagnetic behavior through the carboxylate groups of D-cam ligand. Highlights: • Three homochiral 3D coordination polymers were synthesized. • 1 and 2 are 3D structure with metal-D-cam helical chains pillared by pyrazine. • 3 shows a 3D homochiral framework involving 1D manganese-carboxylate chains. • Magnetic data analysis indicates that 1–3 exhibit weak antiferromagnetic coupling.« less

Building a Library Web Site on the Pillars of Web 2.0

ERIC Educational Resources Information Center

Coombs, Karen A.

2007-01-01

In this article, the author discusses a project they undertook to reshape the libraries' Web services of the University of Houston site. The site had been in a state of flux and it needed a new structure for both managing and organizing it. She realized the staff was looking for a Web site that was more "Web 2.0" in nature. Web 2.0 is often…

Impact resistance of metal skin-carbon fiber reinforced polymer laminate structures for the production of lightweight vehicles body frame

NASA Astrophysics Data System (ADS)

Quagliato, Luca; Dongwook, Kim; Changsoon, Jang; Naksoo, Kim; Seokmoo, Hong

2017-05-01

The research presented in this paper deals, in the first part, with the material characterization of an innovative class of material, made of steel skin and sheet molding compound core, the last one realized with vinyl-ester resin and chopped carbon fibers. Utilizing the results of the material characterization, the case of an automotive B-pillar is taken into account in order to test and prove the reliability of the utilization of this innovative typology of material, instead of the standard steel. The steel skin - SMC hybrid laminate structures are realized by means of stamping process under warm forming condition, in order to favorite the curing of the SMC layers. The result presented along the paper will show that the steel skin - SMC material not only have better specific resistance that those of both standard and high strength steel but also better crashworthiness properties, in comparison to the considered steel. Based on the results of the numerical simulations, a useful way thought which to estimate the crash worthiness property is proposed in this paper and the results will show how the B-pillar realized with steel skin - SMC has a higher impact resistance, in comparison the steel one with the same weight and reduced thickness.

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

Li, Na; Huang, Rudan, E-mail: huangrd@bit.edu.cn

Six new inorganic–organic hybrids based on rigid triangular N-containing ligands, NaCu{sup I}{sub 2}(tib){sub 4}(H{sub 2}O){sub 4}[H{sub 2}PW{sup V}W{sup VI}{sub 11}O{sub 40}][H{sub 2}PW{sup VI}{sub 12}O{sub 40}]·6H{sub 2}O (1), Cu{sup II}{sub 3}(tib){sub 4}Cl{sub 4}[H{sub 2}PW{sup VI}{sub 12}O{sub 40}]{sub 2}·4H{sub 2}O (2), Co(tib){sub 2}[PW{sup V}{sub 3}W{sup VI}{sub 9}O{sub 38}]·5H{sub 2}O (3), Cu{sup II}{sub 3}(tib){sub 2}[P{sub 2}Mo{sup VI}{sub 5}O{sub 22}(O{sub 2})]·4H{sub 2}O (4), Mn(pytpy){sub 2}Mo{sup VI}{sub 4}O{sub 13} (5) and Co(pytpy){sub 2}Mo{sup VI}{sub 4}O{sub 13} (6) (tib=1,3,5-tris(1-imidazolyl)benzene, pytpy=4’-(4”-pyridyl)2,4’:6’,4”-terpyridine), have been hydrothermally synthesized. Single crystal X-ray diffraction studies revealed that compounds 1–4 display two-dimensional (2D) layered structures, and in compounds 1–3, the adjacent Keggin anionsmore » link with each other by W–O–W covalent interactions to form 1D inorganic chains. Compounds 5–6 are 3D “pillar-layer” frameworks based on bimetal–oxide layers pillared by the pytpy ligands. The compounds have been characterized by elemental analysis, powder X−ray diffraction, X-ray photoelectron spectroscopy and thermo gravimetric analyses. Moreover, the electrochemical and catalytic properties of compound 1 have been investigated as well. - Graphical abstract: Six new inorganic–organic hybrids based on rigid triangular N-containing ligands have been obtained under hydrothermal conditions and characterized by single-crystal X-ray diffraction analyses, elemental analyses, IR spectra, and thermogravimetric (TG) analyses. Compounds 1–4 display two-dimensional (2D) layers structure, and in compounds 1–3, the adjacent Keggin anions link with each other by W–O–W covalent interactions to form 1D inorganic Keggin anions chains. Compounds 5–6 are 3D “pillar-layer” frameworks based on bimetal–oxide layers pillared by the pytpy ligands. - Highlights: • MOFs based on POMs have been prepared. • Six new compounds based on rigid triangular N-containing ligands. • The adjacent POMs only share the oxygen atom to form a 1D inorganic Keggin chains.« less

Wide View of 'Mystic Mountain'

NASA Image and Video Library

2017-12-08

NASA image release April 22, 2010 This craggy fantasy mountaintop enshrouded by wispy clouds looks like a bizarre landscape from Tolkien's "The Lord of the Rings" or a Dr. Seuss book, depending on your imagination. The NASA Hubble Space Telescope photograph, which is stranger than fiction, captures the chaotic activity atop a three-light-year-tall pillar of gas and dust that is being eaten away by the brilliant light from nearby bright stars. The pillar is also being assaulted from within, as infant stars buried inside it fire off jets of gas that can be seen streaming from towering peaks. This turbulent cosmic pinnacle lies within a tempestuous stellar nursery called the Carina Nebula, located 7,500 light-years away in the southern constellation Carina. The image marks the 20th anniversary of Hubble's launch and deployment into Earth orbit. Scorching radiation and fast winds (streams of charged particles) from hot newborn stars in the nebula are shaping and compressing the pillar, causing new stars to form within it. Streamers of hot ionized gas can be seen flowing off the ridges of the structure, and wispy veils of dust, illuminated by starlight, float around its peaks. The pillar is resisting being eroded by radiation much like a towering butte in Utah's Monument Valley withstands erosion by water and wind. Nestled inside this dense mountain are fledgling stars. Long streamers of gas can be seen shooting in opposite directions off the pedestal at the top of the image. Another pair of jets is visible at another peak near the center of the image. These jets are the signpost for new star birth. The jets are launched by swirling disks around the stars, as these disks allow material to slowly accrete onto the stars' surfaces. Hubble's Wide Field Camera 3 observed the pillar on Feb. 1-2, 2010. The colors in this composite image correspond to the glow of oxygen (blue), hydrogen and nitrogen (green), and sulfur (red). Object Names: HH 901, HH 902 Image Type: Astronomical Credit: NASA, ESA, and M. Livio and the Hubble 20th Anniversary Team (STScI) To read learn more about this image go to: www.nasa.gov/mission_pages/hubble/science/hubble20th-img.... NASA Goddard Space Flight Center is home to the nation's largest organization of combined scientists, engineers and technologists that build spacecraft, instruments and new technology to study the Earth, the sun, our solar system, and the universe.

Straightforward Generation of Pillared, Microporous Graphene Frameworks for Use in Supercapacitors.

PubMed

Yuan, Kai; Xu, Yazhou; Uihlein, Johannes; Brunklaus, Gunther; Shi, Lei; Heiderhoff, Ralf; Que, Mingming; Forster, Michael; Chassé, Thomas; Pichler, Thomas; Riedl, Thomas; Chen, Yiwang; Scherf, Ullrich

2015-11-01

Microporous, pillared graphene-based frameworks are generated in a simple functionalization/coupling procedure starting from reduced graphene oxide. They are used for the fabrication of high-performance supercapacitor devices. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Bringing home the health humanities: narrative humility, structural competency, and engaged pedagogy.

PubMed

Tsevat, Rebecca K; Sinha, Anoushka A; Gutierrez, Kevin J; DasGupta, Sayantani

2015-11-01

As health humanities programs grow and thrive across the country, encouraging medical students to read, write, and become more reflective about their professional roles, educators must bring a sense of self-reflexivity to the discipline itself. In the health humanities, novels, patient histories, and pieces of reflective writing are often treated as architectural spaces or "homes" that one can enter and examine. Yet, narrative-based learning in health care settings does not always allow its participants to feel "at home"; when not taught with a critical attention to power and pedagogy, the health humanities can be unsettling and even dangerous. Educators can mitigate these risks by considering not only what they teach but also how they teach it.In this essay, the authors present three pedagogical pillars that educators can use to invite learners to engage more fully, develop critical awareness of medical narratives, and feel "at home" in the health humanities. These pedagogical pillars are narrative humility (an awareness of one's prejudices, expectations, and frames of listening), structural competency (attention to sources of power and privilege), and engaged pedagogy (the protection of students' security and well-being). Incorporating these concepts into pedagogical practices can create safe and productive classroom spaces for all, including those most vulnerable and at risk of being "unhomed" by conventional hierarchies and oppressive social structures. This model then can be translated through a parallel process from classroom to clinic, such that empowered, engaged, and cared-for learners become empowering, engaging, and caring clinicians.

Rockburst Disaster Prediction of Isolated Coal Pillar by Electromagnetic Radiation Based on Frictional Effect

PubMed Central

Zhao, Tongbin; Yin, Yanchun; Xiao, Fukun; Tan, Yunliang; Zou, Jianchao

2014-01-01

Based on the understanding that charges generated during coal cracking are due to coal particle friction, a microstructure model was developed by considering four different variation laws of friction coefficient. Firstly, the frictional energy release of coal sample during uniaxial compressive tests was investigated and discussed. Then electromagnetic radiation method was used to predict the potential rockburst disaster in isolated coal pillar mining face, Muchengjian Colliery. The results indicate that the friction coefficient of coal particles decreases linearly with the increase of axial loading force. In predicting the strain-type rockburst, the high stress state of coal must be closely monitored. Field monitoring shows that electromagnetic radiation signal became abnormal before the occurrence of rockburst during isolated coal pillar mining. Furthermore, rockburst tends to occur at the early and ending stages of isolated coal pillar extraction. Mine-site investigation shows the occurrence zone of rockburst is consistent with the prediction, proving the reliability of the electromagnetic radiation method to predict strain-type rockburst disaster. PMID:25054186

Rockburst disaster prediction of isolated coal pillar by electromagnetic radiation based on frictional effect.

PubMed

Zhao, Tongbin; Yin, Yanchun; Xiao, Fukun; Tan, Yunliang; Zou, Jianchao

2014-01-01

Based on the understanding that charges generated during coal cracking are due to coal particle friction, a microstructure model was developed by considering four different variation laws of friction coefficient. Firstly, the frictional energy release of coal sample during uniaxial compressive tests was investigated and discussed. Then electromagnetic radiation method was used to predict the potential rockburst disaster in isolated coal pillar mining face, Muchengjian Colliery. The results indicate that the friction coefficient of coal particles decreases linearly with the increase of axial loading force. In predicting the strain-type rockburst, the high stress state of coal must be closely monitored. Field monitoring shows that electromagnetic radiation signal became abnormal before the occurrence of rockburst during isolated coal pillar mining. Furthermore, rockburst tends to occur at the early and ending stages of isolated coal pillar extraction. Mine-site investigation shows the occurrence zone of rockburst is consistent with the prediction, proving the reliability of the electromagnetic radiation method to predict strain-type rockburst disaster.

Acoustic changes in voice after tonsillectomy.

PubMed

Saida, H; Hirose, H

1996-01-01

The vocal tract from the glottis to the lips is considered to he a resonator and the voice is changeable depending upon the shape of the vocal tract. In this report, we examined the change in pharyngeal size and acoustic feature of voice after tonsillectomy. Subjects were 20 patients. The distance between both anterior pillars (glossopalatine arches), and between both posterior pillars (pharyngopalatine arches) was measured weekly. For acoustic measurements, the five Japanese vowels and Japanese conversational sentences were recorded and analyzed. The distance between both anterior pillars became wider 2 weeks postoperatively, and tended to become narrower thereafter. The distance between both posterior pillars became wider even after 4 weeks postoperatively. No consistent changes in F0, F1 and F2 were found after surgery. Although there was a tendency for a decrease in F3, tonsillectomy did not appear to change the acoustical features of the Japanese vowels remarkably. It was assumed that the subject may adjust the shape of the vocal tract to produce consistent speech sounds after the surgery using auditory feedback.

Model for teaching population health and community-based care across diverse clinical experiences.

PubMed

Van Dyk, Elizabeth J; Valentine-Maher, Sarah K; Tracy, Janet P

2015-02-01

The pillars constructivist model is designed to offer a unifying clinical paradigm to support consistent learning opportunities across diverse configurations of community and public health clinical sites. Thirty-six students and six faculty members participated in a mixed methods evaluation to assess the model after its inaugural semester of implementation. The evaluation methods included a rating scale that measures the model's ability to provide consistent learning opportunities at both population health and direct care sites, a case study to measure student growth within the five conceptual pillars, and a faculty focus group. Results revealed that the model served as an effective means of clinical education to support the use of multiple, small-scale public health sites. Although measurements of student growth within the pillars are inconclusive, the findings suggest efficacy. The authors recommend the continued use of the pillars constructivist model in baccalaureate programs, with further study of the author-designed evaluation tools. Copyright 2015, SLACK Incorporated.

Bioinspired orientation-dependent friction.

PubMed

Xue, Longjian; Iturri, Jagoba; Kappl, Michael; Butt, Hans-Jürgen; del Campo, Aránzazu

2014-09-23

Spatular terminals on the toe pads of a gecko play an important role in directional adhesion and friction required for reversible attachment. Inspired by the toe pad design of a gecko, we study friction of polydimethylsiloxane (PDMS) micropillars terminated with asymmetric (spatular-shaped) overhangs. Friction forces in the direction of and against the spatular end were evaluated and compared to friction forces on symmetric T-shaped pillars and pillars without overhangs. The shape of friction curves and the values of friction forces on spatula-terminated pillars were orientation-dependent. Kinetic friction forces were enhanced when shearing against the spatular end, while static friction was stronger in the direction toward the spatular end. The overall friction force was higher in the direction against the spatula end. The maximum value was limited by the mechanical stability of the overhangs during shear. The aspect ratio of the pillar had a strong influence on the magnitude of the friction force, and its contribution surpassed and masked that of the spatular tip for aspect ratios of >2.

Influence of nanoscale topology on bactericidal efficiency of black silicon surfaces

NASA Astrophysics Data System (ADS)

Linklater, Denver P.; Khuong Duy Nguyen, Huu; Bhadra, Chris M.; Juodkazis, Saulius; Ivanova, Elena P.

2017-06-01

The nanostructuring of materials to create bactericidal and antibiofouling surfaces presents an exciting alternative to common methods of preventing bacterial adhesion. The fabrication of synthetic bactericidal surfaces has been inspired by the anti-wetting and anti-biofouling properties of insect wings, and other topologies found in nature. Black silicon is one such synthetic surfaces which has established bactericidal properties. In this study we show that time-dependent plasma etching of silicon wafers using 15, 30, and 45 min etching intervals, is able to produce different surface geometries with linearly increasing heights of approximately 280, 430, and 610 nm, respectively. After incubation on these surfaces with Gram-positive Staphylococcus aureus and Gram-negative Pseudomonas aeruginosa bacterial cells it was established that smaller, more densely packed pillars exhibited the greatest bactericidal activity with 85% and 89% inactivation of bacterial cells, respectively. The decrease in the pillar heights, pillar cap diameter and inter-pillar spacing corresponded to a subsequent decrease in the number of attached cells for both bacterial species.

Coalescence-induced jumping of micro-droplets on heterogeneous superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Attarzadeh, Reza; Dolatabadi, Ali

2017-01-01

The phenomenon of droplets coalescence-induced self-propelled jumping on homogeneous and heterogeneous superhydrophobic surfaces was numerically modeled using the volume of fluid method coupled with a dynamic contact angle model. The heterogeneity of the surface was directly modeled as a series of micro-patterned pillars. To resolve the influence of air around a droplet and between the pillars, extensive simulations were performed for different droplet sizes on a textured surface. Parallel computations with the OpenMP algorithm were used to accelerate computation speed to meet the convergence criteria. The composition of the air-solid surface underneath the droplet facilitated capturing the transition from a no-slip/no-penetration to a partial-slip with penetration as the contact line at triple point started moving to the air pockets. The wettability effect from the nanoscopic roughness and the coating was included in the model by using the intrinsic contact angle obtained from a previously published study. As the coalescence started, the radial velocity of the coalescing liquid bridge was partially reverted to the upward direction due to the counter-action of the surface. However, we found that the velocity varied with the size of the droplets. A part of the droplet kinetic energy was dissipated as the merged droplet started penetrating into the cavities. This was due to a different area in contact between the liquid and solid and, consequently, a higher viscous dissipation rate in the system. We showed that the effect of surface roughness is strongly significant when the size of the micro-droplet is comparable with the size of the roughness features. In addition, the relevance of droplet size to surface roughness (critical relative roughness) was numerically quantified. We also found that regardless of the viscous cutoff radius, as the relative roughness approached the value of 44, the direct inclusion of surface topography was crucial in the modeling of the droplet-surface interaction. Finally, we validated our model against existing experimental data in the literature, verifying the effect of relative roughness on the jumping velocity of a merged droplet.

A randomised controlled trial on the Four Pillars Approach in managing pregnant women with anaemia in Yogyakarta–Indonesia: a study protocol

PubMed Central

2014-01-01

Background Anaemia is a common health problem among pregnant women and a contributing factor with a major influence on maternal mortality in Indonesia. The Four Pillars Approach is a new approach to anaemia in pregnancy, combining four strategies to improve antenatal and delivery care. The primary objective of this study is to measure the effectiveness of the Four Pillars Approach. The barriers, the facilitators, and the patients’ as well as the midwives’ satisfaction with the Four Pillars Approach will also be measured. Methods/Design This study will use a cluster randomised controlled trial. This intervention study will be conducted in the Public Health Centres with basic emergency obstetric care in Yogyakarta Special Province and in Central Java Province. We will involve all the Public Health Centres (24) with emergency obstetric care in Yogyakarta Special Province. Another 24 Public Health Centres with emergency obstetric care in Central Java Province which have similarities in their demographic, population characteristics, and facilities will also be involved. Each Public Health Centre will be asked to choose two or three nurse-midwives to participate in this study. For the intervention group, the Public Health Centres in Yogyakarta Special Province, training on the Four Pillars Approach will be held prior to the model’s implementation. Consecutively, we will recruit 360 pregnant women with anaemia to take part in part in the study to measure the effectiveness of the intervention. The outcome measurements are the differences in haemoglobin levels between the intervention and control groups in the third trimester of pregnancy, the frequency of antenatal care attendance, and the presence of a nurse-midwife during labour. Qualitative data will be used to investigate the barriers and facilitating factors, as to nurse-midwives’ satisfaction with the implementation of the Four Pillars Approach. Discussion If the Four Pillars Approach is effective in improving the outcome for pregnant women with anaemia, this approach could be implemented nationwide and be taken into consideration to improve the outcome for other conditions in pregnancy, after further research. Trial registration Current Controlled Trials ISRCTN35822126. PMID:24884497

The influence of low-energy helium plasma on bubble formation in micro-engineered tungsten

NASA Astrophysics Data System (ADS)

Gao, Edward; Nadvornick, Warren; Doerner, Russ; Ghoniem, Nasr M.

2018-04-01

Four different types of micro-engineered tungsten surfaces were exposed to low energy helium plasma, with a planar surface as control. These samples include two surfaces covered with uniform W-coated rhenium micro-pillars; one with cylindrical pillars 1 μm in diameter and 25 μm in height, and one with dendritic conical pillars 4-10 μm in diameter and 20 μm in height. Additionally, two samples with reticulated open-cell foam geometry, one at 45 pores per inch (PPI), and the other at 80 PPI were fabricated with Chemical Vapor Deposition (CVD). The samples were exposed to helium plasma at 30-100 eV ion energy, 823-1123 K temperature, and 5 × 1025 - 2 × 1026 m-2 ion fluence. It is shown that the formation of nanometer-scale tendrils (fuzz) on micro-engineered W surfaces is greatly reduced as compared to planar surfaces. This is attributed to more significant ion backscattering and the increased effective surface area that intercept incident ions in micro-engineered W. A 20% decrease in the average ion incident angle on pillar type surfaces leads to ∼30% decrease in bubble size, down to 30 nm in diameter. W fuzz was found to be absent from pillar sides due to high ion backscattering rates from pillar sides. In foam samples, 28% higher PPI is observed to have 24.7%-36.7% taller fuzz, and 17.0%-25.0% larger subsurface bubbles. These are found to be an order of magnitude smaller than those found in planar surfaces of similar environment. The helium bubble density was found to increase with ion energy in pillars, roughly from 8.2% to 48.4%, and to increase with increasing PPI, from 36.4% to 116.2%, and with bubble concentrations up to 9.1 × 1021 m-3. Geometric shadowing effects in or near surface ligaments are observed in all foam samples, with near absence of helium bubbles or fuzz in deeper layers of the foam.

A randomised controlled trial on the Four Pillars Approach in managing pregnant women with anaemia in Yogyakarta-Indonesia: a study protocol.

PubMed

Widyawati, Widyawati; Jans, Suze; Bor, Hans; Siswishanto, Rukmono; van Dillen, Jeroen; Lagro-Janssen, Antoine L M

2014-05-07

Anaemia is a common health problem among pregnant women and a contributing factor with a major influence on maternal mortality in Indonesia. The Four Pillars Approach is a new approach to anaemia in pregnancy, combining four strategies to improve antenatal and delivery care. The primary objective of this study is to measure the effectiveness of the Four Pillars Approach. The barriers, the facilitators, and the patients' as well as the midwives' satisfaction with the Four Pillars Approach will also be measured. This study will use a cluster randomised controlled trial. This intervention study will be conducted in the Public Health Centres with basic emergency obstetric care in Yogyakarta Special Province and in Central Java Province. We will involve all the Public Health Centres (24) with emergency obstetric care in Yogyakarta Special Province. Another 24 Public Health Centres with emergency obstetric care in Central Java Province which have similarities in their demographic, population characteristics, and facilities will also be involved. Each Public Health Centre will be asked to choose two or three nurse-midwives to participate in this study. For the intervention group, the Public Health Centres in Yogyakarta Special Province, training on the Four Pillars Approach will be held prior to the model's implementation. Consecutively, we will recruit 360 pregnant women with anaemia to take part in part in the study to measure the effectiveness of the intervention. The outcome measurements are the differences in haemoglobin levels between the intervention and control groups in the third trimester of pregnancy, the frequency of antenatal care attendance, and the presence of a nurse-midwife during labour. Qualitative data will be used to investigate the barriers and facilitating factors, as to nurse-midwives' satisfaction with the implementation of the Four Pillars Approach. If the Four Pillars Approach is effective in improving the outcome for pregnant women with anaemia, this approach could be implemented nationwide and be taken into consideration to improve the outcome for other conditions in pregnancy, after further research. Current Controlled Trials ISRCTN35822126.

Interconnected magnetic tunnel junctions for spin-logic applications

NASA Astrophysics Data System (ADS)

Manfrini, Mauricio; Vaysset, Adrien; Wan, Danny; Raymenants, Eline; Swerts, Johan; Rao, Siddharth; Zografos, Odysseas; Souriau, Laurent; Gavan, Khashayar Babaei; Rassoul, Nouredine; Radisic, Dunja; Cupak, Miroslav; Dehan, Morin; Sayan, Safak; Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A.; Mocuta, Dan; Radu, Iuliana P.

2018-05-01

With the rapid progress of spintronic devices, spin-logic concepts hold promises of energy-delay conscious computation for efficient logic gate operations. We report on the electrical characterization of domain walls in interconnected magnetic tunnel junctions. By means of spin-transfer torque effect, domains walls are produced at the common free layer and its propagation towards the output pillar sensed by tunneling magneto-resistance. Domain pinning conditions are studied quasi-statically showing a strong dependence on pillar size, ferromagnetic free layer width and inter-pillar distance. Addressing pinning conditions are detrimental for cascading and fan-out of domain walls across nodes, enabling the realization of domain-wall-based logic technology.

From conventional drainage to sustainable stormwater management: Beyond the technical challenges.

PubMed

Goulden, Shula; Portman, Michelle E; Carmon, Naomi; Alon-Mozes, Tal

2018-08-01

Countries and cities are increasingly recognizing the value of adopting Sustainable Stormwater Management (SSWM) goals and measures. SSWM serves multiple hydrological, ecological, social and economic goals and can replace substantial parts of conventional drainage infrastructure. Following international experience in the socio-technical nature of transitions in stormwater management, this research investigates how socio-institutional factors enable the transition from conventional to sustainable stormwater management over time. The research is based on analysing available relevant documents, semi-structured interviews and focus groups, all in a single country case study (Israel). We found significant changes in professional awareness and discourse, some advances in professional standards of work and changes to the regulative system, supporting infiltration practices in particular. We concluded that the three-pillared socio-institutional framework, composed of cultural-cognitive, normative and regulative changes, was insightful for mapping factors supporting transition from conventional drainage to SSWM. Elements within the three pillars can work simultaneously and synergistically to achieve widespread change. At the same time, while SSWM always strives to achieve multiple goals, the order of priority of the various goals may differ from place to place and may change over time. Thus the transition process across the socio-institutional pillars should be renewed if and when the priority of goals changes. The urban and regional planning system can play a crucial role in enhancing the transition process from conventional to sustainable stormwater management. These conclusions may be relevant to other localities and countries that are struggling with such transitions to sustainability. Copyright © 2018 Elsevier Ltd. All rights reserved.

"One-for-All" Strategy in Fast Energy Storage: Production of Pillared MOF Nanorod-Templated Positive/Negative Electrodes for the Application of High-Performance Hybrid Supercapacitor.

PubMed

Qu, Chong; Liang, Zibin; Jiao, Yang; Zhao, Bote; Zhu, Bingjun; Dang, Dai; Dai, Shuge; Chen, Yu; Zou, Ruqiang; Liu, Meilin

2018-06-01

Currently, metal-organic frameworks (MOFs) are intensively studied as active materials for electrochemical energy storage applications due to their tunable structure and exceptional porosities. Among them, water stable pillared MOFs with dual ligands have been reported to exhibit high supercapacitor (SC) performance. Herein, the "One-for-All" strategy is applied to synthesize both positive and negative electrodes of a hybrid SC (HSC) from a single pillared MOF. Specifically, Ni-DMOF-TM ([Ni(TMBDC)(DABCO) 0.5 ], TMBDC: 2,3,5,6-tetramethyl-1,4-benzenedicarboxylic acid, DABCO: 1,4-diazabicyclo[2.2.2]-octane) nanorods are directly grown on carbon fiber paper (CFP) (denoted as CFP@TM-nanorods) with the help of triethylamine and function as the positive electrode of HSC under alkaline electrolyte. Meanwhile, calcinated N-doped hierarchical porous carbon nanorods (CFP@TM-NPCs) are produced and utilized as the negative counter-electrode from a one-step heat treatment of CFP@TM-nanorods. After assembling these two electrodes together to make a hybrid device, the TM-nanorods//TM-NPCs exhibit a wide voltage window of 1.5 V with a high sloping discharge plateau between 1-1.2 V, indicating its great potential for practical applications. This as-described "One-for-All" strategy is widely applicable and highly reproducible in producing MOF-based electrode materials for HSC applications, which shortens the gap between experimental synthesis and practical application of MOFs in fast energy storage. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ethnomathematics: The use of multiple linier regression Y = b 1 X 1 + b 2 X 2 + e in traditional house construction Saka Roras in Songan Village

NASA Astrophysics Data System (ADS)

Darmayasa, J. B.; Wahyudin; Mulyana, T.

2018-01-01

Ethnomathematics may be the connecting bridge between culture and technology and arts. Therefore, the exploration of mathematics values that intersects with cultural anthropology should be significantly conducted. One case containing such issue is the construction of Traditional House of Saka Roras in Bali. Thus, this research aimed to explore the mathematic concept adopted in the construction of such traditional Bale (house) located in Songan Village, Kintamani, Bali. Specifically, this research also aimed to investigate the selection of linear regression coefficient for the saka (pillar) in the Bale. This research applied Embedded Mix-Method Design. Meanwhile, the data collection was conducted by interview, observation and measurement of pillars of 32 Bale Saka Roras. The result of this research revealed that the connection between the width and height of pillars was stated in the formula Y = 26,3 + 18,2X, where X acted as stimulus variable. The coefficient value amounted to 18.2 showed that most preceding architects in Songan Village were more likely to use 19 as the coefficient towards the pillar width than the other coefficients such as 17, 20 and 21 as mentioned in book/palm-leaf manuscript entitled Kosala-Kosali. The last but not least, the researchers also figured out that the pillar width depended on the length of the house-owner candidate’s index finger.

Rapid implantation of dissolving microneedles on an electrospun pillar array.

PubMed

Yang, Huisuk; Kim, Soyoung; Huh, Inyoung; Kim, Suyong; Lahiji, Shayan F; Kim, Miroo; Jung, Hyungil

2015-09-01

Dissolving microneedles (DMNs), designed to release drugs and dissolve after skin insertion, have been spotlighted as a novel transdermal delivery system due to their advantages such as minimal pain and tissue damage, ability to self-administer, and no associated hazardous residues. The drug delivery efficacy of DMNs, however, is limited by incomplete insertion and the extended period required for DMN dissolution. Here, we introduce a novel DMN delivery system, DMN on an electrospun pillar array (DEPA), which can rapidly implant DMNs into skin. DMNs were fabricated on a pillar array covered by a fibrous sheet produced by electrospinning PLGA solution (14%, w/v). DMNs were implanted into the skin by manual application (press and vibration for 10 s) by tearing of the fibers hung on the 300-μm pillars. Separation of DMNs from the fibrous sheet was dependent on both pillar height and the properties of the fibrous sheet. After evaluation of the implantation and dissolution of DMNs with diffusion of red dye by taking cross-sectional images of porcine skin, the hypoglycemic effect of insulin loaded DEPA was examined using a healthy mouse model. This DMN array overcomes critical issues associated with the low penetration efficiency of flat patch-based DMNs, and will allow realization of patient convenience with the desired drug efficacy. Copyright © 2015 Elsevier Ltd. All rights reserved.

Mechanical properties of nano and bulk Fe pillars using molecular dynamics and dislocation dynamics simulation

NASA Astrophysics Data System (ADS)

Nath, S. K. Deb

2017-10-01

Using molecular dynamics simulation, tension and bending tests of a Fe nanopillar are carried out to obtain its Young's modulus and yield strength. Then the comparative study of Young's modulus and yield strength of a Fe nanopillar under bending and tension are carried out varying its diameter in the range of diameter 1-15nm. We find out the reasons why bending Young's modulus and yield strength of a Fe nanopillar are higher than those of tension Young's modulus and yield strength of a Fe nanopillar. Using the mobility parameters of bulk Fe from the experimental study [N. Urabe and J. Weertman, Materials Science and Engineering 18, 41 (1975)], its temperature dependent stress-strain relationship, yield strength and strain hardening modulus are obtained from the dislocation dynamics simulations. Strain rate dependent yield strength and strain hardening modulus of bulk Fe pillars under tension are studied. Temperature dependent creep behaviors of bulk Fe pillars under tension are also studied. To verify the soundness of the present dislocation dynamics studies of the mechanical properties of bulk Fe pillars under tension, the stress vs. strain relationship and dislocation density vs. strain of bulk Fe pillars obtained by us are compared with the published results obtained by S. Queyreau, G. Monnet, and B. Devincre, International Journal of Plasticity 25, 361 (2009).

Electrically driven nanopillars for THz quantum cascade lasers.

PubMed

Amanti, M I; Bismuto, A; Beck, M; Isa, L; Kumar, K; Reimhult, E; Faist, J

2013-05-06

In this work we present a rapid and parallel process for the fabrication of large scale arrays of electrically driven nanopillars for THz quantum cascade active media. We demonstrate electrical injection of pillars of 200 nm diameter and 2 µm height, over a surface of 1 mm(2). THz electroluminescence from the nanopillars is reported. This result is a promising step toward the realization of zero-dimensional structure for terahertz quantum cascade lasers.

The effect of hydrazine intercalation on the structure and capacitance of 2D titanium carbide (MXene)

DOE PAGES

Mashtalir, O.; Lukatskaya, Maria R.; Kolesnikov, Alexander I.; ...

2016-03-25

Herein we show that hydrazine intercalation into 2D titanium carbide (Ti 3C 2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti 3C 2T x layers pre-opening the structure and improving the accessability to active sites. Furthermore, the hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g –1 in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm.

Investigation of radiation damage tolerance in interface-containing metallic nano structures

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

Greer, Julia R.

The proposed work seeks to conduct a basic study by applying experimental and computational methods to obtain quantitative influence of helium sink strength and proximity on He bubble nucleation and growth in He-irradiated nano-scale metallic structures, and the ensuing deformation mechanisms and mechanical properties. We utilized a combination of nano-scale in-situ tension and compression experiments on low-energy He-irradiated samples combined with site-specific microstructural characterization and modeling efforts. We also investigated the mechanical deformation of nano-architected materials, i.e. nanolattices which are comprised of 3-dimensional interwoven networks of hollow tubes, with the wall thickness in the nanometer range. This systematic approach willmore » provide us with critical information for identifying key factors that govern He bubble nucleation and growth upon irradiation as a function of both sink strength and sink proximity through an experimentally-confirmed physical understanding. As an outgrowth of these efforts, we performed irradiations with self-ions (Ni 2+) on Ni-Al-Zr metallic glass nanolattices to assess their resilience against radiation damage rather than He-ion implantation. We focused our attention on studying individual bcc/fcc interfaces within a single nano structure (nano-pillar or a hollow tube): a single Fe (bcc)-Cu (fcc) boundary per pillar oriented perpendicular to the pillar axes, as well as pure bcc and fcc nano structures. Additional interfaces of interest include bcc/bcc and metal/metallic glass all within a single nano-structure volume. The model material systems are: (1) pure single crystalline Fe and Cu, (2) a single Fe (bcc)-Cu (fcc) boundary per nano structure (3) a single metal–metallic glass, all oriented non-parallel to the loading direction so that their fracture strength can be tested. A nano-fabrication approach, which involves e-beam lithography and templated electroplating, as well as two-photon lithography, was utilized, which enabled precise control of the initial microstructure control. Experimentally determined stress-strain relationships were enhanced by in-situ SEM observations coupled with TEM microstructural characterization of the same samples before and after deformation (irradiated and as-fabricated) and atomistic (MD) modeling. A comprehensive suite of experiments was conducted to quantitatively assess the key parameters for He bubble nucleation and growth by independently varying the sink strength, sink proximity, and He implantation temperature and dose. The implantations were conducted at Sandia and Los Alamos National Labs (CINT). Nano structuress containing He-enriched interfaces and irradiation-damaged microstructure were tested under uniaxial tension to assess embrittlement, resulting boundary strength, and deformation mechanisms. Results of this work helped identify which types of interfaces are particularly resilient against radiation damage.« less

The Sixth Pillar of Reading Instruction: Knowledge Development

ERIC Educational Resources Information Center

Cervetti, Gina N.; Hiebert, Elfrieda H.

2015-01-01

The National Reading Panel (NRP) identified five pillars, or essential components, of reading instruction that lead to the highest chance of reading success--phonemic awareness, phonics, fluency, vocabulary, and comprehension. A decade after the NRP's report, the majority of US states adopted the Common Core State Standards/English Language Arts…

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

30 CFR 75.203 - Mining methods.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Mining methods. 75.203 Section 75.203 Mineral... SAFETY STANDARDS-UNDERGROUND COAL MINES Roof Support § 75.203 Mining methods. (a) The method of mining... faulty pillar recovery methods. Pillar dimensions shall be compatible with effective control of the roof...

A non-symmetric pillar[5]arene based on triazole-linked 8-oxyquinolines as a sequential sensor for thorium(IV) followed by fluoride ions.

PubMed

Fang, Yuyu; Li, Caixia; Wu, Lei; Bai, Bing; Li, Xing; Jia, Yiming; Feng, Wen; Yuan, Lihua

2015-09-07

A novel non-symmetric pillar[5]arene bearing triazole-linked 8-oxyquinolines at one rim was synthesized and demonstrated as a sequential fluorescence sensor for thorium(iv) followed by fluoride ions with high sensitivity and selectivity.

Accountability Pillar Results for Annual Education Results Report (AERR)

ERIC Educational Resources Information Center

Alberta Education, 2008

2008-01-01

Alberta has developed an innovative new way of measuring performance to ensure we continue to provide the best possible education opportunities for all of our students. This accountability framework, called the Accountability Pillar, recognizes and respects the outstanding work seen in our school authorities every day. It ensures school…

Six Pillars of Organic Chemistry

ERIC Educational Resources Information Center

Mullins, Joseph J.

2008-01-01

This article describes an approach to teaching organic chemistry, which is to have students build their knowledge of organic chemistry upon a strong foundation of the fundamental concepts of the subject. Specifically, the article focuses upon a core set of concepts that I call "the six pillars of organic chemistry": electronegativity, polar…

Pillars of Progress. Lumina Foundation Focus. Spring 2008

ERIC Educational Resources Information Center

Powell, David S., Ed.

2008-01-01

Minority-Serving Institutions (MSIs) often go above and beyond the call of duty to encourage engagement and provide support to traditionally underrepresented students. This issue of Lumina Foundation Focus magazine, titled "Pillars of progress," examines MSIs and their efforts to maximize student success. Following the President's Message, In…

Pillars of Support: A Functional Asset-Based Framework for ABE Learners

ERIC Educational Resources Information Center

Reynolds, Sharon; Johnson, Jerry

2014-01-01

This paper reported results from a qualitative analysis of assets and supports disclosed in the narratives of adult basic education students. These students were identified as exemplary by their instructors for academic achievement, hours of program attendance, or community service. Themes were identified using the "Four Pillars"…

Numerical simulation of vehicle crashworthiness and occupant protection

NASA Astrophysics Data System (ADS)

Saha, Nripen K.

1993-08-01

Numerical simulation of vehicle crashworthiness and occupant protection are addressed. The vehicle crashworthiness design objectives are to design the vehicle structure for optimum impact energy absorption, and to design the restraint system (seatbelts, airbags, bolsters, etc.) for optimum occupant protection. The following approaches are taken; a major part of the impact energy is to be absorbed by the vehicle structure; the restraint components will provide protection against the remaining crash energy; certain vehicle components are designed to deform under specific types and speeds of impact in a desired mode for sound energy management; structural components such as front side rails, rear rails, door structure and pillars undergo large amounts of deformation; and with properly designed geometry and material these components assist in mitigating the effects of impact.

Numerical simulation of vehicle crashworthiness and occupant protection

NASA Technical Reports Server (NTRS)

Saha, Nripen K.

1993-01-01

Numerical simulation of vehicle crashworthiness and occupant protection are addressed. The vehicle crashworthiness design objectives are to design the vehicle structure for optimum impact energy absorption, and to design the restraint system (seatbelts, airbags, bolsters, etc.) for optimum occupant protection. The following approaches are taken; a major part of the impact energy is to be absorbed by the vehicle structure; the restraint components will provide protection against the remaining crash energy; certain vehicle components are designed to deform under specific types and speeds of impact in a desired mode for sound energy management; structural components such as front side rails, rear rails, door structure and pillars undergo large amounts of deformation; and with properly designed geometry and material these components assist in mitigating the effects of impact.

Full pillar extraction at the Kathleen Mine with mobile roof supports

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

Grimm, E.S.

1994-12-31

The Voest Alpine Breaker Line Supports (ABLS) resemble self-propelled longwall shields. Each individual unit consists of four hydraulic legs extending from the base of the unit, pressing a solid flat canopy against the mine roof. Each support unit is capable of exerting 606 tons of force against the roof. A chain curtain on the sides and rear protects the interior of the support from falling rock. The internal scissoring lemniscate design allows for parallel movement of the canopy as it is raised or lowered. Each ABLS has 750 feet of 4 AWG trailing cable to supply 480 volts AC tomore » a permissible controller and a 40 hp explosion-proof electrical motor. The hydraulic pump and reservoir are self-contained and protected with an automatic fire suppression system.« less

Contraception for adolescents.

PubMed

2014-10-01

Contraception is a pillar in reducing adolescent pregnancy rates. The American Academy of Pediatrics recommends that pediatricians develop a working knowledge of contraception to help adolescents reduce risks of and negative health consequences related to unintended pregnancy. Over the past 10 years, a number of new contraceptive methods have become available to adolescents, newer guidance has been issued on existing contraceptive methods, and the evidence base for contraception for special populations (adolescents who have disabilities, are obese, are recipients of solid organ transplants, or are HIV infected) has expanded. The Academy has addressed contraception since 1980, and this policy statement updates the 2007 statement on contraception and adolescents. It provides the pediatrician with a description and rationale for best practices in counseling and prescribing contraception for adolescents. It is supported by an accompanying technical report. Copyright © 2014 by the American Academy of Pediatrics.

Directional self-cleaning superoleophobic surface.

PubMed

Zhao, Hong; Law, Kock-Yee

2012-08-14

In this work, we report the creation of a grooved surface comprising 3 μm grooves (height ~4 μm) separated by 3 μm from each other on a silicon wafer by photolithography. The grooved surface was then modified chemically with a fluorosilane layer (FOTS). The surface property was studied by both static and dynamic contact angle measurements using water, hexadecane, and a polyethylene wax ink as the probing liquids. Results show that the grooved surface is both superhydrophobic and superoleophobic. Its observed contact angles agree well with the calculated Cassie-Baxter angles. More importantly, we are able to make a replica of the composite wax ink-air interface and study it by SEM. Microscopy results not only show that the droplet of the wax ink "sits" on air in the composite interface but also further reveal that the ink drop actually pins underneath the re-entrant structure in the side wall of the grooved structure. Contact angle measurement results indicate that wetting on the grooved surface is anisotropic. Although liquid drops are found to have lower static and advancing contact angles in the parallel direction, the drops are found to be more mobile, showing smaller hysteresis and lower sliding angles (as compared to the FOTS wafer surface and a comparable 3-μm-diameter pillar array FOTS surface). The enhanced mobility is attributable to the lowering of the resistance against an advancing liquid because 50% of the advancing area is made of a solid strip where the liquid likes to wet. This also implies that the contact line for advancing is no longer smooth but rather is ragged, having the solid strip area leading the wetting and the air strip area trailing behind. This interpretation is supported by imaging the geometry of the contact lines using molten ink drops recovered from the sliding angle experiments in both the parallel and orthogonal directions. Because the grooved surface is mechanically stronger against mechanical abrasion, the self-cleaning effect exhibited in the parallel direction suggests that groove texturing is a viable approach to create mechanically robust, self-cleaning, superoleophobic surfaces.

Landbased Instrumentation Handbook: Western Test Range

DTIC Science & Technology

1981-07-01

17 - 2-11 Quad Helix Antenna TRS, Overview 2-19 2-12 8-Foot Antenna, TRS 2-20 2-13 IRIG Standard Data Transmission Format 2-24 2-14 Pillar Point AFS...Point B-8 B-8 AN/FPS-16, Pillar Point B-9 B-9 35-Foot, ATTRAS B-10 B-10 GKR-7 B-11 B-11 8-Foot Antenna 8-12 B-12 Right Hand Quad Helix B-13 B-13 Right...Hand Quad Helix B-14 B-14 40-Foot Antenna, Pillar Pt. B-15 B-15 LA-24 Tran. Peak B-16 B-16 AN/FPQ-14, Kaena Point B-17 B-17 CCT No. 1 B-18 B-18 CCT No

Fully integrated micro-separator with soft-magnetic micro-pillar arrays for filtrating lymphocytes.

PubMed

Dong, Tao; Su, Qianhua; Yang, Zhaochu; Karlsen, Frank; Jakobsen, Henrik; Egeland, Eirik Bentzen; Hjelseth, Snorre

2010-01-01

A fully integrated micro-separator with soft-magnetic micro-pillar arrays has been developed, which merely employs one independent Lab-On-Chip to realize the lymphocytes isolation from the human whole blood. The simulation, fabrication and experiment are executed to realize this novel microseparator. The simulation results show that, the soft-magnetic micro-pillars array can amplify and redistribute the electromagnetic field generated by the microcoils. The tests certify desirable separation efficiency can be realized using this new separator at low current. No extra cooling system is required for such a micro-separator. This micro-separator can also be used to separate other target cells or particles with the same principle.

Subwavelength photonic crystal waveguide with trapezoidal shaped dielectric pillars in optical systems

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

Xu, Xiaochuan; Chen, Ray T.

2017-02-07

A method for reducing loss in a subwavelength photonic crystal waveguide bend is disclosed. The method comprising: forming the subwavelength photonic crystal waveguide bend with a series of trapezoidal shaped dielectric pillars centered about a bend radius; wherein each of the trapezoidal shaped dielectric pillars comprise a top width, a bottom width, and a trapezoid height; wherein the length of the bottom width is greater than the length of the top width; and wherein the bottom width is closer to the center of the bend radius of the subwavelength photonic crystal waveguide bend than the top width. Other embodiments aremore » described and claimed.« less

Positioning and joining of organic single-crystalline wires

PubMed Central

Wu, Yuchen; Feng, Jiangang; Jiang, Xiangyu; Zhang, Zhen; Wang, Xuedong; Su, Bin; Jiang, Lei

2015-01-01

Organic single-crystal, one-dimensional materials can effectively carry charges and/or excitons due to their highly ordered molecule packing, minimized defects and eliminated grain boundaries. Controlling the alignment/position of organic single-crystal one-dimensional architectures would allow on-demand photon/electron transport, which is a prerequisite in waveguides and other optoelectronic applications. Here we report a guided physical vapour transport technique to control the growth, alignment and positioning of organic single-crystal wires with the guidance of pillar-structured substrates. Submicrometre-wide, hundreds of micrometres long, highly aligned, organic single-crystal wire arrays are generated. Furthermore, these organic single-crystal wires can be joined within controlled angles by varying the pillar geometries. Owing to the controllable growth of organic single-crystal one-dimensional architectures, we can present proof-of-principle demonstrations utilizing joined wires to allow optical waveguide through small radii of curvature (internal angles of ~90–120°). Our methodology may open a route to control the growth of organic single-crystal one-dimensional materials with potential applications in optoelectronics. PMID:25814032

Efficient stabilization of Saccharomyces cerevisiae external invertase by immobilisation on modified beidellite nanoclays.

PubMed

Andjelković, Uroš; Milutinović-Nikolić, Aleksandra; Jović-Jovičić, Nataša; Banković, Predrag; Bajt, Teja; Mojović, Zorica; Vujčić, Zoran; Jovanović, Dušan

2015-02-01

The external invertase isoform 1 (EINV1) was immobilised on eight differently modified beidellite nanoclays. Modifications were composed of organo-modification with different amounts of surfactant - hexadecyl trimethylammonium cation (HDTMA), pillaring with Al/Fe containing polyhydroxy cations and acid modification of Na-enriched and pillared clays. The modified nanoclays were characterised by XRD, N2-physisorption, SEM and FT-IR spectroscopy. The amount of bound enzyme activity was significantly influenced by the modification of beidellite ranging from 50 to remarkable 2200U/g. Biochemical characterization was performed for five modified nanoclays showing the highest enzyme activity after invertase immobilisation. The investigation demonstrated that after immobilisation the structure and the catalytic properties of invertase were preserved, while Km values were slightly increased from 26 to 37mM. immobilisation significantly improved thermal and storage stability of EINV1. Results indicate that beidellite nanoclays obtained by low cost modifications can be applied as a suitable support for the immobilisation of invertase. The immobilizate can be efficiently engaged in sucrose hydrolysis in batch reactor. Copyright © 2014 Elsevier Ltd. All rights reserved.

Talent Development as a University Mission: The Quadruple Helix

ERIC Educational Resources Information Center

Holm-Nielsen, Lauritz B.; Thorn, Kristian; Olesen, Jeppe Dorup; Huey, Tina

2013-01-01

In this paper, the authors discuss the rationale behind making talent development at the PhD, post-doctoral and early career levels an equal fourth pillar of the university's mission, alongside the more traditional pillars of the triple helix. Using Denmark and Aarhus University as a case study, the paper describes how increased institutional…

77 FR 9850 - Safety Zone; 2012 Mavericks Invitational, Half Moon Bay, CA

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-21

...-AA08 Safety Zone; 2012 Mavericks Invitational, Half Moon Bay, CA AGENCY: Coast Guard, DHS. ACTION... Pillar Point in the navigable waters of Half Moon Bay, California. The regulation will temporarily... the navigable waters of Half Moon Bay in vicinity of Pillar Point. The Coast Guard will enforce a...

Character, Social-Emotional, and Academic Outcomes among Underachieving Elementary School Students

ERIC Educational Resources Information Center

Grier, Leslie K.

2012-01-01

One purpose of this research was to examine the psychometric properties of a character assessment scale (the Character Assessment for School Age Children; CASAC) based on 6 pillars of character (Josephson Institute, 2009). Many youth development and character education programs utilize some, if not all, of the pillars of character explicitly or…

Air Mobility Issues 2002. Air Force Jounral of Logistics. Volume 26, Number 1, Spring 2002

DTIC Science & Technology

2002-01-01

referred to as organizations. Three Pillars of Legitimacy Based on a review of institutional theory , Scott suggested a set of institutional domains he...of legitimacy, the cognitive pillar, draws from social psychology and the cognitive school of institutional theory . 17 When measured through the cognit

Six Pillars of Dynamic Schools

ERIC Educational Resources Information Center

Edwards, Steven W.; Chapman, Paul E.

2009-01-01

"Six Pillars of Dynamic Schools" uncovers an often overlooked truth--effective change is the product of hard work and dedication. There is no silver bullet; no matter how many programs, software packages, or new initiatives a district uses, the magic won't just "happen." Dynamic schools result from consistent and redundant focus on the fundamental…

A pillar[5]arene based gel from a low-molecular-weight gelator for sustained dye release in water.

PubMed

Yao, Yong; Sun, Yan; Yu, Huaxu; Chen, Wenrui; Dai, Hong; Shi, Yujun

2017-12-12

A soft gel based on pillar[5]arene was successfully prepared using a carbazone reaction. Furthermore, dyes such as TPP or TPPE can be incorporated into this gel and were observed to be released in a sustained way in water due to solvent exchange.

Promoting Family Literacy through the Five Pillars of Family and Community Engagement (FACE)

ERIC Educational Resources Information Center

Kuo, Nai-Cheng

2016-01-01

Family literacy involves factors beyond what is done at home between parents and children. To help preservice teachers develop their understanding of the multiple dimensions of family literacy, this study uses the five pillars of family and community engagement (FACE)--early literacy, family involvement, access to books, expanded learning, and…

30 CFR 75.334 - Worked-out areas and areas where pillars are being recovered.

Code of Federal Regulations, 2011 CFR

2011-07-01

... be used to control spontaneous combustion, accumulations of methane-air mixtures, and other gases... pillars have been recovered shall be— (1) Ventilated so that methane-air mixtures and other gases, dusts... be used to control the air passing through the area and to continuously dilute and move methane-air...

30 CFR 75.334 - Worked-out areas and areas where pillars are being recovered.

Code of Federal Regulations, 2010 CFR

2010-07-01

... be used to control spontaneous combustion, accumulations of methane-air mixtures, and other gases... pillars have been recovered shall be— (1) Ventilated so that methane-air mixtures and other gases, dusts... be used to control the air passing through the area and to continuously dilute and move methane-air...

30 CFR 75.334 - Worked-out areas and areas where pillars are being recovered.

Code of Federal Regulations, 2013 CFR

2013-07-01

... be used to control spontaneous combustion, accumulations of methane-air mixtures, and other gases... pillars have been recovered shall be— (1) Ventilated so that methane-air mixtures and other gases, dusts... be used to control the air passing through the area and to continuously dilute and move methane-air...

30 CFR 75.334 - Worked-out areas and areas where pillars are being recovered.

Code of Federal Regulations, 2014 CFR

2014-07-01

... be used to control spontaneous combustion, accumulations of methane-air mixtures, and other gases... pillars have been recovered shall be— (1) Ventilated so that methane-air mixtures and other gases, dusts... be used to control the air passing through the area and to continuously dilute and move methane-air...

30 CFR 75.334 - Worked-out areas and areas where pillars are being recovered.

Code of Federal Regulations, 2012 CFR

2012-07-01

... be used to control spontaneous combustion, accumulations of methane-air mixtures, and other gases... pillars have been recovered shall be— (1) Ventilated so that methane-air mixtures and other gases, dusts... be used to control the air passing through the area and to continuously dilute and move methane-air...

The Sloan-C Pillars and Boundary Objects As a Framework for Evaluating Blended Learning

ERIC Educational Resources Information Center

Laumakis, Mark; Graham, Charles; Dziuban, Chuck

2009-01-01

The authors contend that blended learning represents a boundary object; a construct that brings together constituencies from a variety of backgrounds with each of these cohorts defining the object somewhat differently. The Sloan-C Pillars (learning effectiveness, access, cost effectiveness, student satisfaction, and faculty satisfaction) provide…

Parallel-plate submicron gap formed by micromachined low-density pillars for near-field radiative heat transfer

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

Ito, Kota, E-mail: kotaito@mosk.tytlabs.co.jp; Research Center for Advanced Science and Technology; Miura, Atsushi

Near-field radiative heat transfer has been a subject of great interest due to the applicability to thermal management and energy conversion. In this letter, a submicron gap between a pair of diced fused quartz substrates is formed by using micromachined low-density pillars to obtain both the parallelism and small parasitic heat conduction. The gap uniformity is validated by the optical interferometry at four corners of the substrates. The heat flux across the gap is measured in a steady-state and is no greater than twice of theoretically predicted radiative heat flux, which indicates that the parasitic heat conduction is suppressed tomore » the level of the radiative heat transfer or less. The heat conduction through the pillars is modeled, and it is found to be limited by the thermal contact resistance between the pillar top and the opposing substrate surface. The methodology to form and evaluate the gap promotes the near-field radiative heat transfer to various applications such as thermal rectification, thermal modulation, and thermophotovoltaics.« less

Friction enhancement via micro-patterned wet elastomer adhesives on small intestinal surfaces.

PubMed

Kwon, Jiwoon; Cheung, Eugene; Park, Sukho; Sitti, Metin

2006-12-01

A micro-pillar-based silicone rubber adhesive coated with a thin silicone oil layer is investigated in this paper for developing friction-based clamping mechanisms for robotic endoscopic microcapsules. These adhesives are shown to enhance the frictional force between the capsule and the intestinal wall by a factor of about seven over a non-patterned flat elastomer material. In this study, tests performed on fresh samples of pig small intestine are used to optimize the diameter of the micro-pillars to maximize the frictional forces. In addition, the effects of other factors such as the oil viscosity and applied normal forces are investigated. It is demonstrated that the proposed micro-pillar pattern based elastomer adhesive exhibits a maximal frictional force when the pillar diameter is 140 microm and coated silicon oil has a very high viscosity (10,000 cSt). It is also found that the frictional force of the micro-patterned adhesive increases nonlinearly in proportion to the applied normal force. These adhesives would be used as a robust attachment material for developing robotic capsule endoscopes inside intestines with clamping capability.

A framework for sustainable invasive species management: environmental, social and economic objectives

USGS Publications Warehouse

Larson, Diane L.; Phillips-Mao, Laura; Quiram, Gina; Sharpe, Leah; Stark, Rebecca; Sugita, Shinya; Weiler, Annie

2011-01-01

Applying the concept of sustainability to invasive species management (ISM) is challenging but necessary, given the increasing rates of invasion and the high costs of invasion impacts and control. To be sustainable, ISM must address environmental, social, and economic factors (or *pillars*) that influence the causes, impacts, and control of invasive species across multiple spatial and temporal scales. Although these pillars are generally acknowledged, their implementation is often limited by insufficient control options and significant economic and political constraints. In this paper, we outline specific objectives in each of these three *pillars* that, if incorporated into a management plan, will improve the plan's likelihood of sustainability. We then examine three case studies that illustrate how these objectives can be effectively implemented. Each pillar reinforces the others, such that the inclusion of even a few of the outlined objectives will lead to more effective management that achieves ecological goals, while generating social support and long-term funding to maintain projects to completion. We encourage agency directors and policy-makers to consider sustainability principles when developing funding schemes, management agendas, and policy.

Direct formation of nano-pillar arrays by phase separation of polymer blend for the enhanced out-coupling of organic light emitting diodes with low pixel blurring.

PubMed

Lee, Cholho; Han, Kyung-Hoon; Kim, Kwon-Hyeon; Kim, Jang-Joo

2016-03-21

We have demonstrated a simple and efficient method to fabricate OLEDs with enhanced out-coupling efficiencies and with low pixel blurring by inserting nano-pillar arrays prepared through the lateral phase separation of two immiscible polymers in a blend film. By selecting a proper solvent for the polymer and controlling the composition of the polymer blend, the nano-pillar arrays were formed directly after spin-coating of the polymer blend and selective removal of one phase, needing no complicated processes such as nano-imprint lithography. Pattern size and distribution were easily controlled by changing the composition and thickness of the polymer blend film. Phosphorescent OLEDs using the internal light extraction layer containing the nano-pillar arrays showed a 30% enhancement of the power efficiency, no spectral variation with the viewing angle, and only a small increment in pixel blurring. With these advantages, this newly developed method can be adopted for the commercial fabrication process of OLEDs for lighting and display applications.

Tuning magnetic properties of magnetoelectric BiFeO 3-NiFe 2O 4 nanostructures

NASA Astrophysics Data System (ADS)

Crane, S. P.; Bihler, C.; Brandt, M. S.; Goennenwein, S. T. B.; Gajek, M.; Ramesh, R.

2009-02-01

Multifunctional thin film nanostructures containing soft magnetic materials such as nickel ferrite are interesting for potential applications in microwave signal processing because of the possibility to shrink the size of device architecture and limit device power consumption. An essential prerequisite to future applications of such a system is a firm understanding of its magnetic properties. We show that nanostructures composed of ferrimagnetic NiFe 2O 4 pillars in a multiferroic BiFeO 3 matrix can be tuned magnetically by altering the aspect ratio of the pillars by depositing films of varying thickness. Magnetic anisotropy is studied using ferromagnetic resonance, which shows that the uniaxial magnetic anisotropy in the growth direction changes sign upon increasing the film thickness. The magnitude of this anisotropy contribution can be explained via a combination of shape and magnetostatic effects, using the object-oriented micromagnetic framework (OOMMF). The key factors determining the magnetic properties of the films are shown to be the aspect ratio of individual pillars and magnetostatic interactions between neighboring pillars.

Friction enhancement via micro-patterned wet elastomer adhesives on small intestinal surfaces

NASA Astrophysics Data System (ADS)

Kwon, Jiwoon; Cheung, Eugene; Park, Sukho; Sitti, Metin

2006-12-01

A micro-pillar-based silicone rubber adhesive coated with a thin silicone oil layer is investigated in this paper for developing friction-based clamping mechanisms for robotic endoscopic microcapsules. These adhesives are shown to enhance the frictional force between the capsule and the intestinal wall by a factor of about seven over a non-patterned flat elastomer material. In this study, tests performed on fresh samples of pig small intestine are used to optimize the diameter of the micro-pillars to maximize the frictional forces. In addition, the effects of other factors such as the oil viscosity and applied normal forces are investigated. It is demonstrated that the proposed micro-pillar pattern based elastomer adhesive exhibits a maximal frictional force when the pillar diameter is 140 µm and coated silicon oil has a very high viscosity (10 000 cSt). It is also found that the frictional force of the micro-patterned adhesive increases nonlinearly in proportion to the applied normal force. These adhesives would be used as a robust attachment material for developing robotic capsule endoscopes inside intestines with clamping capability.

In-chip direct laser writing of a centimeter-scale acoustic micromixer

NASA Astrophysics Data System (ADS)

van't Oever, Jorick; Spannenburg, Niels; Offerhaus, Herman; van den Ende, Dirk; Herek, Jennifer; Mugele, Frieder

2015-04-01

A centimeter-scale micromixer was fabricated by two-photon polymerization inside a closed microchannel using direct laser writing. The structure consists of a repeating pattern of 20 μm×20 μm×155 μm acrylate pillars and extends over 1.2 cm. Using external ultrasonic actuation, the micropillars locally induce streaming with flow speeds of 30 μm s-1. The fabrication method allows for large flexibility and more complex designs.

Peculiar behavior of MWW materials in aldol condensation of furfural and acetone.

PubMed

Kikhtyanin, Oleg; Chlubná, Pavla; Jindrová, Tereza; Kubička, David

2014-07-21

MWW family of different structural types (MCM-22, MCM-49, MCM-56 and MCM-36) was used as catalysts for aldol condensation of furfural and acetone studied in a batch reactor at 100 °C, autogenous pressure and a reaction time of 0-4 h. To establish a relation between physico-chemical and catalytic properties of microporous materials, the samples were characterized by XRD, SEM, N2 adsorption, FTIR and TGA. It was found that the acidic solids possessed appreciable activity in the reaction and resulted in the formation of products of aldehyde-ketone interaction. Surprisingly, MCM-22 and MCM-49, i.e. three-dimensional materials containing internal supercages, exhibited higher activity than two MCM-36 catalysts with two-dimensional character having larger accessible external surface area due to expansion of the interlayer space by swelling and pillaring treatments. Moreover, all MWW family catalysts gave higher conversion than the large-pore zeolite BEA. Nevertheless, furfural conversion decreased rapidly for all the studied materials due to coke formation. Unexpectedly, the deactivation was found to be more severe for MCM-36 catalysts than for MCM-22 and MCM-49, which was attributed to the reaction taking place also in supercages that are protected by 10-ring channels from severe coking. In contrast the cups located on the external surface were coked rapidly.

Influence of Plastic Deformation on Martensitic Transformation During Hot Stamping of Complex Structure Auto Parts

NASA Astrophysics Data System (ADS)

Shen, Yuhan; Song, Yanli; Hua, Lin; Lu, Jue

2017-04-01

The ultra-high strength steel auto parts manufactured by hot stamping are widely applied for weight reduction and safety improvement. During the hot stamping process, hot forming and quenching are performed in one step wherein plastic deformation and phase transformation simultaneously take place and affect each other. Thereinto, the influence of deformation on martensitic transformation is of great importance. In the present paper, the influence of plastic deformation on martensitic transformation during hot stamping of complex structure auto parts was investigated. For this purpose, a B-pillar reinforced panel in B1500HS steel was manufactured by hot stamping, and the process was simulated by finite element software based on a thermo-mechanical-metallurgical coupled model. Considering various deformation degrees, the microstructures and mechanical properties at four typical locations of the hot stamped B-pillar reinforced panel were detected. The results show that the martensitic content and the microhardness increase with the increase in the deformation amount. There are two reasons causing this phenomenon: (1) the increase in mechanical driving force and (2) the increased probability of the martensitic nucleation at crystal defects. The x-ray diffraction analysis indicates the carbon enrichment in retained austenite which results from the carbon diffusion during the low-carbon martensite formation. Furthermore, the carbon content decreases with the increase in the deformation amount, because the deformation of austenite suppresses the carbon diffusion.

Environmental scanning electron microscopy analysis of Proteus mirabilis biofilms grown on chitin and stainless steel.

PubMed

Fernández-Delgado, Milagro; Duque, Zoilabet; Rojas, Héctor; Suárez, Paula; Contreras, Monica; García-Amado, María A; Alciaturi, Carlos

Proteus mirabilis is a human pathogen able to form biofilms on the surface of urinary catheters. Little is known about P. mirabilis biofilms on natural or industrial surfaces and the potential consequences for these settings. The main aim of this work was to assess and compare the adhesion and biofilm formation of P. mirabilis strains from different origins on chitin and stainless steel surfaces within 4 to 96 h. Using environmental scanning electron microscopy, the biofilms of a clinical strain grown on chitin at 4 h showed greater adhesion, aggregation, thickness, and extracellular matrix production than those grown on stainless steel, whereas biofilms of an environmental strain had less aggregation on both surfaces. Biofilms of both P. mirabilis strains developed different structures on chitin, such as pillars, mushrooms, channels, and crystalline-like precipitates between 24 and 96 h, in contrast with flat-layer biofilms produced on stainless steel. Significant differences ( p  < 0.05) were found in the frequency of pillars and channels. Images of transmission electron microscopy demonstrated abundant fimbriae in 100 % of cells from both strains, which could be related to surface adherence and biofilm formation. This represents the first study of P. mirabilis showing adhesion, biofilm formation, and development of different structures on surfaces found outside the human host.

Gecko-Inspired, Controlled Adhesion and Its Applications

NASA Astrophysics Data System (ADS)

Menguc, Yigit

This thesis work is primarily concerned with taking inspiration from the principles of gecko-adhesion in order to control the attachment of synthetic structured adhesives. We present gecko-inspired angled elastomer micropillars with flat or round tip endings as compliant pick-and-place micromanipulators. The pillars are 35 mum in diameter, 90 mum tall, and angled at an inclination of 20°. By gently pressing the tip of a pillar to a part, the pillar adheres to it through intermolecular forces. Next, by retracting quickly, the part is picked from a given donor substrate. During transferring, the adhesion between the pillar and the part is high enough to withstand disturbances due to external forces or the weight of the part. During release of the part onto a receiver substrate, the contact area of the pillar to the part is drastically reduced by controlled vertical or shear displacement, which results in reduced adhesive forces. The maximum repeatable ratio of pick-to-release adhesive forces was measured as 39 to 1. We find that a flat tip shape and shear displacement control provide a higher pick-to-release adhesion ratio than a round tip and vertical displacement control, respectively. We present a model of forces to serve as a framework for the operation of this micromanipulator. Finally, demonstrations of pick-and-place manipulation of mum-scale silicon microplatelets and a cm-scale glass cover slip serve as proofs of concept. The compliant polymer micropillars are safe for use with fragile parts, and, due to exploiting intermolecular forces, could be effective on most materials and in air, vacuum, and liquid environments. We present a study of the self-cleaning and contamination resistance phenomena of synthetic gecko-inspired adhesives made from elastomeric polyurethane. The phenomenon of self-cleaning makes the adhesive foot of the gecko robust against dirt, and makes it effectively sticky throughout the lifetime of the material (within the molting cycles). So far synthetic gecko adhesives fail to capture this behavior and self-cleaning remains the least studied characteristic in the field gecko-inspired adhesives. In this work we use two distinct arrays of micropillars with mushroom-shaped tips made from polyurethane. The two geometries we use all have the same aspect ratios of pillar height to base diameter of about 2 to 1, and all have mushroom tips that are twice the diameter of base. The pillar tip diameters are 20 mum and 95 mum, and we will refer to them as the small and large pillars, respectively. We contaminate the adhesives with simulated dirt particles in the form of well-characterized soda lime glass spheres ranging in diameter from 1 to 250 mum. Both micropillar arrays recovered adhesive strength after contamination and cleaning through dry, shearing contact with glass. In a best case scenario, we found that large pillars contaminated with 150-250 mum diameter particles can rid the tips of contaminating particles completely and recover 90% of the initial adhesive strength. This finding is significant because it is the first demonstration of adhesion recovery through dry self-cleaning by contact to a non-sticky cleaning substrate. The degree to which adhesion is recovered is superior to any conventional adhesive and is nearly identical to the gecko itself. This thesis presents a study of controlling adhesion in gecko-inspired adhesives. This control is achieved by maximizing or minimizing attachment strength on demand by simple mechanical loading, and enables robotic manipulation tasks and the recovery of adhesion after contamination. Looking forward, we can predict what is possible for gecko-inspired adhesives if the discoveries in this thesis are implemented, and if other shortcomings in the field are resolved. Looking at the applications already under development, it seems clear that medical adhesives have great potential, and climbing robots might achieve significant utility. In consumer products, gecko-adhesives might replace VelcroRTMand zippers in clothing, and might become a critical component in sports gear, e.g. soccer goal keeper and rock climber gloves. The reversible, controllable nature of the adhesion, as well as its incredible bonding strength, suggests more impressive possibilities for gecko-inspired adhesives: perhaps it might act as a fastener for temporary or emergency construction. We might yet see rolls of single-sided and double-sided gecko-tape sold in hardware stores, not as a replacement for duct tape, but as a replacement for nails, staples and screws. (Abstract shortened by UMI.)

Evaluation of Pillars4life: a virtual coping skills program for cancer survivors.

PubMed

Smith, Sophia K; O'Donnell, Jonathan D; Abernethy, Amy P; MacDermott, Kristin; Staley, Tina; Samsa, Gregory P

2015-11-01

Pillars4Life is an educational program that teaches coping skills to cancer patients in a virtual group setting; it was recently implemented at 17 hospitals across the USA. The cost-effective, scalable, and assessable Pillars4Life curriculum targets psychosocial resources (e.g., self-efficacy and coping skills) as a means to reduce symptoms (e.g., depression, anxiety, and posttraumatic stress) and enhance quality of life. Cancer patients were recruited from hospitals that received the LIVESTRONG Community Impact Project Award to enroll in a pilot study of Pillars4Life. Consenting participants met with a certified instructor weekly for 10 weeks in a virtual environment; the manualized intervention trained participants in personal coping skills. Longitudinal assessments over 6 months were assessed using validated instruments to determine changes in Pillars4Life targeted resources and outcomes. Multiple linear regression models examined the relationship between changes in targeted resources and changes in outcome from baseline to 3 months post-intervention. Participants (n = 130) had the following characteristics: mean age of 56 ± 11 years, 87% women, 11% non-Caucasian, and 77% with college degree. At 3- and 6-month follow-up, mean scores improved on all key outcome measures such as depression (Patient Health Questionnaire), anxiety (Generalized Anxiety Disorder), posttraumatic stress (Posttraumatic Stress Disorder Checklist), fatigue (Functional Assessment of Chronic Illness Therapy-Fatigue), and well-being (Functional Assessment of Cancer Therapy-General) from baseline (all p < 0.01); results were most pronounced among participants who reported ≥4/10 on the Distress Thermometer at baseline (all p < 0.001). Changes in each targeted resource were associated with 3-month improvements in at least one outcome. Participation in the Pillars4Life program was associated with statistically and clinically significant improvements in scores on pre-specified outcomes and targeted resources. Copyright © 2015 John Wiley & Sons, Ltd.

Seismic tomography as a tool for measuring stress in mines

USGS Publications Warehouse

Scott, Douglas F.; Williams, T.J.; Denton, D.K.; Friedel, M.J.

1999-01-01

Spokane Research Center personnel have been investigating the use of seismic tomography to monitor the behavior of a rock mass, detect hazardous ground conditions and assess the mechanical integrity of a rock mass affected by mining. Seismic tomography can be a valuable tool for determining relative stress in deep, >1,220-m (>4,000-ft), underground pillars. If high-stress areas are detected, they can be destressed prior to development or they can be avoided. High-stress areas can be monitored with successive seismic surveys to determine if stress decreases to a level where development can be initiated safely. There are several benefits to using seismic tomography to identify high stress in deep underground pillars. The technique is reliable, cost-effective, efficient and noninvasive. Also, investigators can monitor large rock masses, as well as monitor pillars during the mining cycle. By identifying areas of high stress, engineers will be able to assure that miners are working in a safer environment.Spokane Research Center personnel have been investigating the use of seismic tomography to monitor the behavior of a rock mass, detect hazardous ground conditions and assess the mechanical integrity of a rock mass affected by mining. Seismic tomography can be a valuable tool for determining relative stress in deep, >1,200-m (>4,000-ft), underground pillars. If high-stress areas are detected, they can be destressed prior to development or they can be avoided. High-stress areas can be monitored with successive seismic surveys to determine if stress decreases to a level where development can be initiated safely. There are several benefits to using seismic tomography to identify high stress in deep underground pillars. The technique is reliable, cost-effective, efficient and noninvasive. Also, investigators can monitor large rock masses, as well as monitor pillars during the mining cycle. By identifying areas of high stress. engineers will be able to assure that miners are working in a safer environment.

Measurement and interpretation of crustal deformation rates associated with postglacial rebound

NASA Technical Reports Server (NTRS)

Davis, James L.

1994-01-01

Analysis of Global Positioning System (GPS) data from two sites separated by horizontal distance of only approximately 2.2 m yielded phase residuals exhibiting a systematic elevation angle dependence. One of the two GPS antennas was mounted on an approximately 1 m high concrete pillar, and the other was mounted on a standard wooden tripod. We performed elevation angle cutoff tests with these data, and established that the vertical coordinate of site position was sensitive to the minimum elevation angle (elevation cutoff) of the data analyzed. For example, the vertical coordinate of site position changed by 9.7 plus or minus 0.8 mm when the minimum elevation angle was increased from 10 to 25. We performed simulations based on a simple (ray tracing) multipath model with a single horizontal reflector, and demonstrated that the elevation angle cutoff test results and the pattern of the residual versus elevation angle could be qualitatively reproduced if the reflector were located 0.1-0.2 m beneath the antenna phase center. We therefore, hypothesized that the source of the elevation-angle-dependent error were multipath reflections and scattering and that the horizontal surface of the pillar, located a distance of approximately 0.2 m beneath the antenna phase center, was the primary reflector. We tested this hypothesis by placing microwave absorbing material between the antenna and the pillar in a number of configurations and analyzed the changes in apparent position of the antenna. The results indicate that (1) the horizontal surface of the pillar is indeed the main reflector, (2) both the concrete and the metal plate embedded in the pillar are significant reflectors, and (3) the reflection can be reduced to a great degree by the use of microwave absorbing materials. These results have significant implications for the accuracy of global GPS geodetic tracking networks which use pillar-antenna configuration identical or similar to the one used here (at the Westford WFRD GPS site).

Management of Legg-Calvé-Perthes disease using an A-frame orthosis and hip range of motion: a 25-year experience.

PubMed

Rich, Margaret M; Schoenecker, Perry L

2013-03-01

Containment treatment is widely accepted in the management of Legg-Calvé-Perthes disease. Many reports indicate the need to regain hip motion before pelvic or femoral osteotomy, but have not indicated how osteotomy affected motion. Recent studies have suggested that osteotomy treatment of lateral pillar B hips may result in a higher proportion of spherical hips than those managed nonoperatively; however, outcomes for children older than 8 years of age or with pillar C involvement remain unsatisfactory. The records of all patients with a diagnosis of Legg-Calvé-Perthes disease seen at our facility from 1985 through 2001 were reviewed. Two hundred and thirteen patients (175 males, 38 females), average age 6.4 years (range, 2.6 to 11.3 y), with 240 involved hips in the necrotic or the fragmentation stage were managed under a protocol to restore and maintain satisfactory hip abduction with an adductor tenotomy and abduction cast, followed by daily hip range-of-motion exercises and an A-frame orthosis to facilitate the concentric position of the epiphysis within the acetabulum. Assessment included measurement of hip abduction, femoral head sphericity and congruence, presence of femoral neck deformity, limb-length inequality, and later reconstructive surgical procedures. Hips were grouped by lateral pillar class (12A, 113B, 115C) and evaluated at maturity using a modified Stulberg grade. All pillar A hips were spherically congruent. Of pillar B hips, 101 were spherically congruent, 8 were aspherical but congruent, and 4 were aspherical and incongruent. Of pillar C hips, 77 were spherically congruent, 26 were aspherical but congruent, and 12 were aspherical and incongruent. Age did not correlate with outcome. Hip abduction improved and was maintained in all groups. Treatment that restored and maintained hip range of motion along with the use of an A-frame orthosis resulted in a high proportion of spherically congruent hips for patients of all ages irrespective of the extent of disease. Seventy-eight percent of pillar B and C hips were spherically congruent hips at maturity; overall, 93% of hips were congruent. This regimen has supplanted all other methods of treatment at our institution. Level IV-case series.

Synthesis and Structural Studies of Calcium and Magnesium Phosphinate and Phosphonate Compounds

NASA Astrophysics Data System (ADS)

Bampoh, Victoria Naa Kwale

The work presented herein describes synthetic methodologies leading to the design of a wide array of magnesium and calcium based phosphinate and phosphonates with possible applications as bone scaffolding materials or additives to bone cements. The challenge to the chemistry of the alkaline earth phosphonate target compounds includes poor solubility of compounds, and poorly understood details on the control of the metal's coordination environment. Hence, less is known on phosphonate based alkaline earth metal organic frameworks as compared to transition metal phosphonates. Factors governing the challenges in obtaining crystalline, well-defined magnesium and calcium solids lie in the large metal diameters, the absence of energetically available d-orbitals to direct metal geometry, as well as the overall weakness of the metal-ligand bonds. A significant part of this project was concerned with the development of suitable reaction conditions to obtain X-ray quality crystals of the reaction products to allow for structural elucidation of the novel compounds. Various methodologies to aid in crystal growth including hydrothermal methods and gel crystallization were employed. We have used phosphinate and phosphonate ligands with different number of phosphorus oxygen atoms as well as diphosphonates with different linker lengths to determine their effects on the overall structural features. An interesting correlation is observed between the dimensionality of products and the increasing number of donor oxygen atoms in the ligands as we progress from phosphinic acid to the phosphorous acids. As an example, monophosphinate ligand only yielded one-dimensional compounds, whereas the phosphonates crystallize as one and two-dimensional compounds, and the di- and triphosphonate based compounds display two or three-dimensional geometries. This thesis provides a selection of calcium and magnesium compounds with one-dimensional geometry, as represented in a calcium phosphinate to novel two-dimensional sheets of magnesium and pillared calcium phosphonates. The preparation of these novel compounds has led to the establishment of synthetic protocols that allow for the direct preparation of compounds with defined structural features.

Soft-sediment deformation in a tectonically active area: The Plio-Pleistocene Zarzal Formation in the Cauca Valley (Western Colombia)

NASA Astrophysics Data System (ADS)

Neuwerth, Ralph; Suter, Fiore; Guzman, Carlos A.; Gorin, Georges E.

2006-04-01

The Plio-Pleistocene Zarzal Formation corresponds to fluvio-lacustrine sediments deposited in an intramontane depression within the Colombian Andes, associated with the Cauca-Romeral Fault System. It crops out mainly in the Cauca Valley where numerous field sections have permitted the mapping of the vertical and lateral lithological variations. Lacustrine deposits of sands, silts, clays and diatomites are interbedded with fluvial sand and gravel beds and fluvio-volcanic mass flows derived from the volcanic Central Cordillera. Numerous soft-sediment deformation structures are encountered in this formation, particularly in fine- to medium-grained sands, silts and clays: load structures (load casts, flame structures, pseudonodules), water escape structures (water escape cusps, dish-and-pillar and pocket-and-pillar structures), soft-sediment intrusions (clastic sills and dykes), disturbed laminites, convolute laminations, slumps and synsedimentary faulting. Deformation mechanisms and driving forces are related essentially to gravitational instabilities, dewatering, liquidization and brittle deformations. Field and regional geological data show that most of these deformations are related to seismicity and can be interpreted as seismites. This area has a geological and recent seismic history and outcrops show both syn- and post-depositional faulting related to the transpressional regime of this part of the Colombian Andes, which generates strike-slip faults and associated local normal faults. The drainage pattern within the Zarzal Formation shows the signature of neotectonics. Moreover, the fine to coarse-grained sands of the Zarzal Formation are lithologies prone to liquefaction when affected by seismic waves. The intercalation of the deformed intervals within undisturbed strata confirms the catastrophic nature of the events. Finally, the large areal extent of the deformations and the type of structures are compatible with seismites. Consequently, the existence of seismites in the Zarzal Formation represents corroboration of tectonic activity in this area during the Pleistocene. Earthquakes with a magnitude higher than 5 can be postulated, based upon the proximity of active faults and the types of deformations.

Photoinduced catalytic adsorption of model contaminants on Bi/Cu pillared montmorillonite in the visible light range

EPA Science Inventory

Montmorillonite K10 clay was pillared with BiCl3 and Cu(NO3)2 to extend its applicability as catalytic adsorbent to degrade aqueous solution of anionic azo-dye Methyl Orange (MO) in the presence of visible light irradiation. The preparation of Bi/Cu-montmorillonite utilized benig...

An Operationally Responsive Space Architecture for 2025

DTIC Science & Technology

2008-06-22

Organizational Relationships, Asset Loss Mitigation, Availability, Flexibility, and Streamlined Acquisition Processes . These pillars allowed the solutions...were considered. Analysis was further supported by a performance versus cost process which provided a final test of solution feasibility. Relative cost...Availability, Flexibility, and Streamlined Acquisition Processes . These pillars allowed the solutions, material and non-material, to be organized for

Attitudes towards Saving in Polish Society during Transformation

ERIC Educational Resources Information Center

Roszkiewicz, Malgorzata

2006-01-01

Since 1999 the complex reform of the old-age pension system was introduced in Poland and the process of changes is still ongoing. The multi-pillar system replaced the pay-as-you-go system. Voluntary third pillar will guarantee higher pensions for those that decide to save more. However, the systemic changes were placed in the new market economy…

An AIEE fluorescent supramolecular cross-linked polymer network based on pillar[5]arene host-guest recognition: construction and application in explosive detection.

PubMed

Shao, Li; Sun, Jifu; Hua, Bin; Huang, Feihe

2018-05-08

Here a novel fluorescent supramolecular cross-linked polymer network with aggregation induced enhanced emission (AIEE) properties was constructed via pillar[5]arene-based host-guest recognition. Furthermore, the supramolecular polymer network can be used for explosive detection in both solution and thin films.

An Enquiry into the Professional Competence of Inclusive Education Teachers in Beijing: Attitudes, Knowledge, Skills, and Agency

ERIC Educational Resources Information Center

Mu, Guanglun Michael; Wang, Yan; Wang, Zhiqiang; Feng, Yajing; Deng, Meng; Liang, Songmei

2015-01-01

Attitudes, knowledge, and skills are widely recognised as the three pillars of professional competence of inclusive education teachers. Studies emerging from the Chinese context consider these three pillars important for the practice of Learning in Regular Classrooms--an idiosyncratic Chinese form of inclusive education. Our mixed methods study…

Catholic Schools and the Embodiment of Religiosity: The Development of Catholicity toward the Common Good

ERIC Educational Resources Information Center

Elshof, Toke

2015-01-01

In the Netherlands, the relation between Catholic schools and the Catholic Church was apparent during the pillarized educational system and culture of the first decades of the 20th century. In the post-pillarized decennia afterward, their connection transformed and became less recognizable. At first glance, their contemporary relation sometimes…

Identification of depth information with stereoscopic mammography using different display methods

NASA Astrophysics Data System (ADS)

Morikawa, Takamitsu; Kodera, Yoshie

2013-03-01

Stereoscopy in radiography was widely used in the late 80's because it could be used for capturing complex structures in the human body, thus proving beneficial for diagnosis and screening. When radiologists observed the images stereoscopically, radiologists usually needed the training of their eyes in order to perceive the stereoscopic effect. However, with the development of three-dimensional (3D) monitors and their use in the medical field, only a visual inspection is no longer required in the medical field. The question then arises as to whether there is any difference in recognizing depth information when using conventional methods and that when using a 3D monitor. We constructed a phantom and evaluated the difference in capacity to identify the depth information between the two methods. The phantom consists of acryl steps and 3mm diameter acryl pillars on the top and bottom of each step. Seven observers viewed these images stereoscopically using the two display methods and were asked to judge the direction of the pillar that was on the top. We compared these judged direction with the direction of the real pillar arranged on the top, and calculated the percentage of correct answerers (PCA). The results showed that PCA obtained using the 3D monitor method was higher PCA by about 5% than that obtained using the naked-eye method. This indicated that people could view images stereoscopically more precisely using the 3D monitor method than when using with conventional methods, like the crossed or parallel eye viewing. We were able to estimate the difference in capacity to identify the depth information between the two display methods.

Template method for fabricating interdigitate p-n heterojunction for organic solar cell

PubMed Central

2012-01-01

Anodic aluminum oxide (AAO) templates are used to fabricate arrays of poly(3-hexylthiophene) (P3HT) pillars. This technique makes it possible to control the dimensions of the pillars, namely their diameters, intervals, and heights, on a tens-of-nanometer scale. These features are essential for enhancing carrier processes such as carrier generation, exciton diffusion, and carrier dissociation and transport. An interdigitated p-n junction between P3HT pillars and fullerene (C60) exhibits a photovoltaic effect. Although the device properties are still preliminary, the experimental results indicate that an AAO template is an effective tool with which to develop organic solar cells because highly regulated nanostructures can be produced on large areas exceeding 100 mm2. PMID:22908897

Improved Oxygen-Beam Texturing of Glucose-Monitoring Optics

NASA Technical Reports Server (NTRS)

Banks, Bruce A.

2006-01-01

An improved method has been devised for using directed, hyperthermal beams of oxygen atoms and ions to impart desired textures to the tips of polymethylmethacrylate [PMMA] optical fibers to be used in monitoring the glucose content of blood. The improved method incorporates, but goes beyond, the method described in Texturing Blood-Glucose- Monitoring Optics Using Oxygen Beams (LEW-17642-1), NASA Tech Briefs, Vol. 29, No. 4 (April 2005), page 11a. The basic principle of operation of such a glucose-monitoring sensor is as follows: The textured surface of the optical fiber is coated with chemicals that interact with glucose in such a manner as to change the reflectance of the surface. Light is sent down the optical fiber and is reflected from, the textured surface. The resulting change in reflectance of the light is measured as an indication of the concentration of glucose. The required texture on the ends of the optical fibers is a landscape of microscopic cones or pillars having high aspect ratios (microscopic structures being taller than they are wide). The average distance between hills must be no more than about 5 mso that blood cells (which are wider) cannot enter the valleys between the hills, where they would interfere with optical sensing of glucose in the blood plasma. On the other hand, the plasma is required to enter the valleys, and high aspect ratio structures are needed to maximize the surface area in contact with the plasma, thereby making it possible to obtain a given level of optical glucose-measurement sensitivity with a relatively small volume of blood. There is an additional requirement that the hills be wide enough that a sufficient amount of light can propagate into them and, after reflection, can propagate out of them. The method described in the cited prior article produces a texture comprising cones and pillars that conform to the average-distance and aspect-ratio requirements. However, a significant fraction of the cones and pillars are so narrow that not enough light can propagate along them. The improved method makes it possible to form wider cones and pillars while still satisfying the average-distance and aspect-ratio requirements. In the improved method, as in the previously reported method, multiple optical fibers are first bundled together for simultaneous texturing of their distal tips. However, prior to texturing by exposure to an oxygen beam, the tips are first coated by vapor deposition of a thin, sparse layer of aluminum: The exposure to the aluminum vapor must be short enough (typically of the order of seconds) so that the aluminum nucleates into islands separated by uncoated areas. The coated tips are textured by exposure to a directed beam of hyperthermal (kinetic energy >1 eV) oxygen atoms and/or ions in a vacuum chamber, as in the previously reported method. The aluminum islands partially shield the underlying PMMA from oxidation and erosion by the beam, so that the cones or pillars remaining after texturing are wider than they would otherwise be. To some extent, the dimensions of the hills and the distances between them can be tailored through choice of the thickness of the aluminum coat and/or the oxygen-beam fluence. The figure illustrates an example of texturing of the tip of a PMMA optical fiber without and with prior aluminum coating.

[The cultural history of palliative care in primitive societies: an integrative review].

PubMed

Siles González, José; Solano Ruiz, Maria Del Carmen

2012-08-01

The objective of this study is to describe the evolution of palliative care in order to reflect on the possibility of its origin in primitive cultures and their relationship with the beginnings of the cult of the dead. It describes the change in the symbolic structures and social interactions involved in palliative care during prehistory: functional unit, functional framework and functional element. The theoretical framework is based on cultural history, the dialectical structural model and symbolic interactionism. Categorization techniques, cultural history and dialectic structuralism analyses were performed. Palliative care existed in primitive societies, mostly associated with the rites of passage with a high symbolic content. The social structures - functional unit, functional framework and functional element - are the pillars that supported palliative care in prehistory societies.

Propagating Waves Transverse to the Magnetic Field in a Solar Prominence

NASA Astrophysics Data System (ADS)

Schmieder, B.; Kucera, T. A.; Knizhnik, K.; Luna, M.; Lopez-Ariste, A.; Toot, D.

2013-11-01

We report an unusual set of observations of waves in a large prominence pillar that consist of pulses propagating perpendicular to the prominence magnetic field. We observe a huge quiescent prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly in EUV on 2012 October 10 and only a part of it, the pillar, which is a foot or barb of the prominence, with the Hinode Solar Optical Telescope (SOT; in Ca II and Hα lines), Sac Peak (in Hα, Hβ, and Na-D lines), and THEMIS ("Télescope Héliographique pour l' Etude du Magnétisme et des Instabilités Solaires") with the MTR (MulTi-Raies) spectropolarimeter (in He D3 line). The THEMIS/MTR data indicates that the magnetic field in the pillar is essentially horizontal and the observations in the optical domain show a large number of horizontally aligned features on a much smaller scale than the pillar as a whole. The data are consistent with a model of cool prominence plasma trapped in the dips of horizontal field lines. The SOT and Sac Peak data over the four hour observing period show vertical oscillations appearing as wave pulses. These pulses, which include a Doppler signature, move vertically, perpendicular to the field direction, along thin quasi-vertical columns in the much broader pillar. The pulses have a velocity of propagation of about 10 km s-1, a period of about 300 s, and a wavelength around 2000 km. We interpret these waves in terms of fast magnetosonic waves and discuss possible wave drivers.

ERRATUM: Propagating Waves Transverse to the Magnetic Field in a Solar Prominence

NASA Technical Reports Server (NTRS)

Schmieder, B.; Kucera, T. A.; Knizhnik, K.; Luna, M.; Lopez-Ariste, A.; Toot, D.

2014-01-01

We report an unusual set of observations of waves in a large prominence pillar that consist of pulses propagating perpendicular to the prominence magnetic field. We observe a huge quiescent prominence with the Solar Dynamics Observatory Atmospheric Imaging Assembly in EUV on 2012 October 10 and only a part of it, the pillar, which is a foot or barb of the prominence, with the Hinode Solar Optical Telescope (SOT; in Ca II and Halpha lines), Sac Peak (in Ha, Hß, and Na-D lines), and THEMIS ("Télescope Héliographique pour l' Etude du Magnétisme et des Instabilités Solaires") with the MTR (MulTi-Raies) spectropolarimeter (in He D3 line). The THEMIS/MTR data indicates that the magnetic field in the pillar is essentially horizontal and the observations in the optical domain show a large number of horizontally aligned features on a much smaller scale than the pillar as a whole. The data are consistent with a model of cool prominence plasma trapped in the dips of horizontal field lines. The SOT and Sac Peak data over the four hour observing period show vertical oscillations appearing as wave pulses. These pulses, which include a Doppler signature, move vertically, perpendicular to the field direction, along thin quasi-vertical columns in the much broader pillar. The pulses have a velocity of propagation of about 10 km/s, a period of about 300 s, and a wavelength around 2000 km. We interpret these waves in terms of fast magnetosonic waves and discuss possible wave drivers.

Extending and implementing the Persistent ID pillars

NASA Astrophysics Data System (ADS)

Car, Nicholas; Golodoniuc, Pavel; Klump, Jens

2017-04-01

The recent double decade anniversary of scholarly persistent identifier use has triggered journal special editions such as "20 Years of Persistent Identifiers". For such a publication, it is apt to consider the longevity of some persistent identifier (PID) mechanisms (Digital Object Identifiers) and the partial disappearance of others (Life Sciences IDs). We have previously postulated a set of "PID Pillars" [1] which are design principles aimed at ensuring PIDs can survive technology and social change and thus persist for the long term that we have drawn from our observations of PIDs at work over many years. The principles: describe how to ensure identifiers' system and organisation independence; codify the delivery of essential PID system functions; mandate a separation of PID functions from data delivery mechanisms; and require generation of policies detailing how change is handled. In this presentation, first we extend on our previous work of introducing the pillars by refining their descriptions, giving specific suggestions for each and presenting some work that addresses them. Second, we propose a baseline data model for persistent identifiers that, if used, would assist the separation of PID metadata and PID system functioning. This would allow PID system function specifics to change over time (e.g. resolver services or even resolution protocols) and yet preserve the PIDs themselves. Third, we detail our existing PID system — the PID Service [2] — that partially implements the pillars and describe both its successes and shortcomings. Finally, we describe our planned next-generation system that will aim to use the baseline data model and fully implement the pillars.

Community resilience and Chagas disease in a rural region of Mexico

PubMed Central

Rangel, José Antonio Santana; Monreal, Luz Arenas; Ramsey, Janine M

2016-01-01

ABSTRACT OBJECTIVE To explore the pillars of community resilience in a region where Chagas disease is endemic, with the aim of promoting participatory processes to deal with this condition from the resilience of the population. METHODS Qualitative study using ethnographic record and six interviews of focus groups with young people, women and men. The research was carried out in a rural area of the state of Morelos, Mexico, between 2006 and 2007. We carried out educational sessions with the population in general, so that residents could identify the relationship between the vector Triatoma pallidipennis, the parasite (Trypanosoma cruzi), symptoms, and preventive actions for Chagas disease. The ethnographic record and groups were analyzed based on Taylor and Bogdan’s modification, and the focus was to understand the socio-cultural meanings that guide the speeches and activities of residents in relation to the pillars of community resilience. RESULTS The population felt proud of belonging to that location and three pillars of community resilience were clearly identified: collective self-esteem, cultural identity, and social honesty. Having these pillars as bases, we promoted the participation of the population concerning Chagas disease, and a Community Action Group was formed with young people, adult men and women, and social leaders. This Group initiated actions of epidemiological and entomological surveillance in the community to deal with this problem. CONCLUSIONS It is necessary to create more experiences that deepen the understanding of the pillars of community resilience, and how they contribute to enhance participation in health to deal with Chagas disease. PMID:27509012