Form Of Prisms Research Articles

Antireflective nanostructured zinc oxide arrays produced by pulsed electrodeposition

Conditions for the pulsed electrochemical deposition of nanostructured zinc oxide arrays with a certain morphology, crystal structure, and optical properties from aqueous electrolytes onto substrates of transparent electrically conducting tin dioxide and on single-crystal silicon wafers with built-in homojunctions are studied in order to develop antireflection coatings for solar cells. It is shown that it is possible to obtain single-layer planar antireflection coatings or arrays of nanorods of this material, both having the form of hexagonal prisms and exhibiting the moth-eye effect.

Influence of Chemical Additives on Radiation Stability of Concrete - Theoretical Basis and Evaluation Method

The influence of additives on the radiation stability of the concrete will occur through the influence of radiation changes of hardened cement paste on radiation changes of concrete and can be quite significant. The test sequence was produced according to the modified method described in case [11]. The samples were prepared in the form of prisms with the following dimensions: 10 mm x 10 mm, 30 mm. Measurement series were produced after each heating and cooling sequence. Then the difference between the values before and after heating was calculated.

Further study of the intrinsic safety of internally shorted lithium and lithium-ion cells within methane-air

National Institute for Occupational Safety and Health (NIOSH) researchers continue to study the potential for lithium and lithium-ion battery thermal runaway from an internal short circuit in equipment for use in underground coal mines. Researchers conducted cell crush tests using a plastic wedge within a 20-L explosion-containment chamber filled with 6.5% CH4-air to simulate the mining hazard. The present work extends earlier findings to include a study of LiFePO4 cells crushed while under charge, prismatic form factor LiCoO2 cells, primary spiral-wound constructed LiMnO2 cells, and crush speed influence on thermal runaway susceptibility. The plastic wedge crush was a more severe test than the flat plate crush with a prismatic format cell. Test results indicate that prismatic Saft MP 174565 LiCoO2 and primary spiral-wound Saft FRIWO M52EX LiMnO2 cells pose a CH4-air ignition hazard from internal short circuit. Under specified test conditions, A123 systems ANR26650M1A LiFePO4 cylindrical cells produced no chamber ignitions while under a charge of up to 5 A. Common spiral-wound cell separators are too thin to meet intrinsic safety standards provisions for distance through solid insulation, suggesting that a hard internal short circuit within these cells should be considered for intrinsic safety evaluation purposes, even as a non-countable fault. Observed flames from a LiMnO2 spiral-wound cell after a chamber ignition within an inert atmosphere indicate a sustained exothermic reaction within the cell. The influence of crush speed on ignitions under specified test conditions was not statistically significant.

Hierarchical nanostructures of nickel-doped zinc oxide: Morphology controlled synthesis and enhanced visible-light photocatalytic activity

Nickel-doped zinc oxide hollow nanospheres have been synthesized using a simple solvothermal approach through a morphological transformation driven by a localized Ostwald ripening process. The saturation magnetization of the system shows that the materials have only a short-range magnetic ordering in them. Based on the visible-light photocatalytic experiment, we could confirm that, with a high doping content (10mol%), the doping accompanied with increased recombination which reduced the energy of photoinduced electron leading to suppressed photocatalytic activity. Changing reaction parameters, i.e. the mixed reactant concentration, doping content, and different solvents, Zn1−xNixO powders exhibited the elongated prismatic form with sharp tips, quasi-spherical structure, and hexagonal-based polyhedron, respectively. The photocatalytic results demonstrate that different crystal growth orientations, specific surface areas, particle size distributions, and doping levels have strong influences on the photocatalytic activity performances. Among the samples, hexagonal-based polyhedrons have the best photodegradation efficiency standing on higher fraction of exposed polar facets, larger specific surface area, as well as an optimal doping level. The 1mol% nickel content showed the best photocatalytic activities among the nickel-doped zinc oxide samples.

Theory of X-Ray diffuse scattering from a crystal with pores in the form of triangular prisms

A theory of X-ray diffuse scattering (XRDS) from a crystal with pores in the form of triangular prisms has been developed. Solutions for the static Debye-Waller factor, intrinsic correlation function, and the correlation volume (which characterizes the XRDS angular distribution in reciprocal space) are obtained within this model. A numerical simulation of reciprocal space maps of X-ray diffuse scattering is performed. The influence of pore-size fluctuations on the formation of XRDS intensity isolines is demonstrated.

The physical, chemical and functional characterization of starches from Andean tubers: oca (Oxalis tuberosa Molina), olluco (Ullucus tuberosus Caldas) and mashua (Tropaeolum tuberosum Ruiz & Pavón)

The physical, chemical, and functional properties of starches isolated from the Andean tubers oca (Oxalis tuberosa M.), olluco (Ullucus tuberosus C.) and mashua (Tropaeolum tuberosum R. & P.) were studied. The tubers were obtained from a local grocery. The morphology of the starch granules (size and shape) was studied with scanning electron microscopy (SEM), which revealed ellipsoid, oval, conical, pear-shaped and prismatic forms: ellipsoids and oval granules with lengths up to 54.30 µm in oca; with lengths up to 32.09 µm for olluco starch granules; and with predominantly truncated spherical or oval forms and smaller dimensions (up to 16.29 um) for mashua starch granules. Amylose contents were similar among the samples: 27.60% (oca), 26.49% (olluco) and 27.44% (mashua). Olluco starch had less swelling power, forming opaque, less firm gels. All three starch gels showed the same stability on refrigeration and presented high syneresis under freezing temperatures, with a variation of 40.28 to 74.42% for olluco starch. The starches cooked easily, with high peak viscosity. The low gelatinization temperatures and high stability during cooling make these starches suitable feedstock for use in formulations that require milder processing temperatures and dispense freezing storage.

Structure of prismatic halloysite

The crystal structure of halloysite, despite being one of the most commonly occurring clay minerals on the Earth’s surface, remains elusive. This paper reports on a multi-methodological study to shed more light on the atomic arrangement of halloysite from Olkhon Island, Lake Baikal, Russia, which has a prismatic morphology. It has been investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), selected-area electron diffraction (SAED) and, in particular, high-resolution transmission electron microscopy (HRTEM), to reveal its atomic structure and formation process. XRD analysis indicated a basal spacing of ca. 7.2 A and two characteristic peaks with d = 4.28 and 4.03 A on the tail of the 02,11 band. The halloysite grain cross sections displayed various prismatic forms, ranging from a rectangle to a regular 18-sectored polygon in SEM and TEM. The SAED pattern from a sector of the polygonal prisms with the incident beam parallel to the prism axes showed a regular one-layer oblique reciprocal lattice, similar to that of kaolinite along Y i -directions. HRTEM imaging performed with the new computer-assisted minimal-dose system and an incident beam perpendicular to the prism axis showed stacking of most dioctahedral 1:1 layers with their pseudo-mirror plane perpendicular to the prism axis and an almost random, or rather, alternating lateral stagger to the right or left from the preceding layer, which corresponds to interlayer displacements of τ + and τ − in Zvyagin symbols, or layer displacements of t 1 and t 2 used to describe the stacking in kaolinite. This stacking feature explains the SAED pattern from the side of the prismatic grains and the two characteristic peaks on the tail of the 02,11 band in the XRD pattern. Based on these results, it is proposed that tubular halloysite initially forms as a hydrated one with the pseudo-mirror plane of the kaolinite layers perpendicular to the tube axis, then dehydrates with, possibly, partially hydrogen-bonded interlayers, and finally transforms to a prismatic one consisting of sectored flat layers with the complete hydrogen-bonded interlayers. During this transformation, stacking with comparable ratio and frequent alternation of τ + and τ − is formed, to minimize morphological change of the tubes.

Repulsive forces of highly coercive permanent magnets in magnetic clutches and plane magnetic systems

A formula is derived for calculating the repulsive force of highly coercive permanent magnets made from rare-earth metal alloys in frontal magnetic clutches and plane magnetic systems, when the magnets take the form of rectangular prisms.

FORECASTING MODEL OF MANUFACTURING TIME AT THE EARLY DESIGN STAGE OF PRODUCT AND PROCESS

This paper considers the developed forecasting model of a manufacturing time at the early product and process design stage. Developed model forecasts the manufacturing time of machining operations by removed material volume and achieved part’s quantitative-qualitative characteristics. Presented methodology of manufacturing time forecasting on products and their design features classification is based. The design features into two separate class level – rotational and prismatic geometrical form are classified. Consideration on the virtual environment is made; the mathematical formalization of forecasting manufacturing time and repartition of design features in mechanical parts and products applying statistical analyses methods are defined. The proposals how would be possible to classify the design features of products’ and how to define their influence to the manufacturing time by the removed material volume of separate design features.DOI: http://dx.doi.org/10.5755/j01.mech.19.1.3620

Hybrid photonics structures with grating and prism couplers based on ZnO waveguides

AbstractThis paper presents the results of investigations concerning input-output systems of an electromagnetic wave in the visible and near visible spectrum for their application in structures of integrated optics. The input-output structures used in described planar optical waveguides are in a form of prism and grating couplers. The first part of the paper contains numerical analysis of grating couplers aiming at an optimization of their geometrical parameters, strictly — the depth of the grooves in the grating coupler. The second part presents the practical realization, as well as experimental tests of the planar optical waveguide with the hybrid input-output system. As the input system of the electromagnetic wave, a prism coupler was used, and in the case of the output system — a photonic structure with grating coupler was applied. The investigated planar wave guides with the input-output structures were made of a wide energy band gap semiconductor — zinc oxide (ZnO).

Afterglow by Christopher Ries

Christopher Ries, (1952- ), was raised on a farm in the rural Columbus, Ohio, area. He received his BFA from The Ohio State University in Columbus in 1975 and his MFA from the University of Wisconsin in Madison in 1978, where he served as an assistant to the founder of the American studio glass movement.1Christopher Ries. http://en.wikipedia.org/wiki/Christopher_Ries. Accessed May 9, 2012.Google Scholar, 2Biography Ries website. http://www.christopherries.com/biography.htm. Accessed May 9, 2012.Google Scholar His initial studies delved into glassblowing as an art medium, and he maintained a glassblowing studio for several summers after graduation.1Christopher Ries. http://en.wikipedia.org/wiki/Christopher_Ries. Accessed May 9, 2012.Google Scholar With the aid of the products from a company called Schott Optical Glass, which notes it markets 115 different glass formulas, Ries discovered his defining medium and technique to create a unique, specialized, and new form of glasswork–sculpture.2Biography Ries website. http://www.christopherries.com/biography.htm. Accessed May 9, 2012.Google Scholar, 3Schott Optical website. http://www.us.schott.com/advanced_optics/english/our_products/materials/optical_glass.html. Accessed May 11, 2012.Google Scholar Starting with massive blocks of glass crystal, often weighing as much as 3000 lbs, Ries carves and polishes each piece into highly reflective, refractive, and prismatic forms.4Art Glass Ries website. http://www.christopherries.com/artglass.htm. Accessed April 9, 2012.Google Scholar As with all of Ries' creations, Afterglow contains an internal life of its own. The external boundaries of the glassworks' edges frame a highly dynamic microcosm of its surrounding environment. Each moment a newly introduced object becomes temporarily imprisoned within Afterglow. The structure of the sculpture defined by these lines grants it solidity. Its shape imitates a falling tear or a modern-day award given in honor of excellence. The interior reflections are as volatile as any in a butterfly effect5Glossary definition: Butterfly effect. http://www.pbs.org/faithandreason/physgloss/bfly-body.html. Accessed May 11, 2012.Google Scholar outcome. Each of the 4 images reveal a completely new view of Afterglow in kaleidoscope fashion, depending on the angle, light, or passerby that was present when each view of Afterglow was photographed. If a viewer gets tired of the current image, he needs only to turn his head or squint his eye and a surprising change takes place. Afterglow, sculpted in 2006, is a gift from Elizabeth M. Ross and is located on the 14th floor of the Gonda Building, in Rochester, Minnesota.View Large Image Figure ViewerDownload (PPT)

Calciodelrioite, Ca(VO3)2(H2O)4, the Ca analogue of delrioite, Sr(VO3)2(H2O)4

AbstractCalciodelrioite, ideally Ca(VO3)2(H2O)4, is a new mineral (IMA 2012-031) from the uraniumvanadium deposits of the eastern Colorado Plateau in the USA. The type locality is the West Sunday mine, Slick Rock district, San Miguel County, Colorado. The new mineral occurs on fracture surfaces in corvusite- and montroseite-impregnated sandstone and forms as a result of the oxidative alteration of these phases. At the West Sunday mine, calciodelrioite is associated with celestine, gypsum, huemulite, metarossite, pascoite and rossite. The mineral occurs as transparent colourless needles, bundles of tan to brown needles and star bursts of nearly black broad blades composed of tightly intergrown needles. Crystals are elongate and striated parallel to [100], exhibiting the prismatic forms {001} and {011} and having terminations possibly composed of the forms {100} and {61}. The mineral is transparent and has a white streak, subadamantine lustre, Mohs hardness of about 2½, brittle tenacity, irregular to splintery fracture, one perfect cleavage on {001} and possibly one or more additional cleavages parallel to [100]. Calciodelrioite is soluble in water. The calculated density is 2.451 g cm– 3. It is optically biaxial (+) with α = 1.733(3), β = 1.775(3), γ = 1.825(3) (white light), 2Vmeas = 87.3(9)° and 2Vcalc = 87°. The optical orientation is X = b; Z ≈ a. No pleochroism was observed. Electronmicroprobe analyses of two calciodelrioite samples and type delrioite provided the empirical formulae (Ca0.88Sr0.07Na0.04K0.01)Σ1.00(V1.00O3)2(H2.01O)4, (Ca0.76Sr0.21Na0.01)Σ0.98(V1.00O3)2(H2.01O)4 and (Sr0.67Ca0.32)Σ0.99(V1.00O3)2(H2.00O)4, respectively. Calciodelrioite is monoclinic, I2/a, with unit-cell parameters a = 14.6389(10), b = 6.9591(4), c = 17.052(2) Å, β = 102.568(9)°, V = 1695.5(3) Å3 and Z = 8. The seven strongest lines in the X-ray powder diffraction pattern [listed as dobs Å (I)(hkl)] are as follows: 6.450(100)(011); 4.350(16)(013); 3.489(18)(020); 3.215(17)(022); 3.027(50)(multiple); 2.560(28)(15,413); 1.786(18)(028). In the structure of calciodelrioite (refined to R1 = 3.14% for 1216 Fo > 4σF), V5+O5 polyhedra link by sharing edges to form a zigzag divanadate [VO3] chain along a, similar to that in the structure of rossite. The chains are linked via bonds to Ca atoms, which also bond to H2O groups, yielding CaO3(H2O)6 polyhedra. The Ca polyhedra form a chain along b. Each of the two symmetrically independent VO5 polyhedra has two short vanadyl bonds and three long equatorial bonds. Calciodelrioite and delrioite are isostructural and are the endmembers of the series Ca(VO3)2(H2O)4–Sr(VO3)2(H2O)4. Calciodelrioite is dimorphous with rossite, which has a similar structure; however, the smaller 8-coordinate Ca site in rossite does not accommodate Sr.

Size‐dependent structural properties of quasi‐one‐dimensional silicon clusters

AbstractThe family of quasi‐one‐dimensional silicon clusters of regular hexagonal prism form with the layer number n = 2–4 is investigated by the new quantum‐chemical tight‐binding method. The structural properties of the pristine and hydrogen‐passivated clusters are studied as function of cluster sizes. The optimized geometries of clusters show that the layer sizes change with increasing the number of its. The middle layers widen in comparison to the top and bottom layers. The cluster Si18 trends to the fullerene‐like form. Analysis of the quantum‐chemical calculation results has been conducted in framework of the correlative approach of Wigner and virial theorem. Electron properties are studied separately for each layer. It has been shown that a distinction in radial compressing forces in different layers and dependence of the distinction values from the layer number (i.e. from cluster size) exist (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Unique seven-node rare-earth octacyanomolybdate(IV) three-dimensional molecular frameworks: {[Er(H2O)5(Er(H2O)4)3][Mo(CN)8]3·11H2O}n and {[Eu(H2O)5(Eu(H2O)4)3][Mo(CN)8]3·11H2O}n

The crystal structure analyses of {[Er(H2O)5(Er(H2O)4)3][Mo(CN)8]3·11H2O}n (1) and {[Eu(H2O)5(Eu(H2O)4)3][Mo(CN)8]3·11H2O}n (2), show that they are not only new neutral three-dimensional rare-earth octacyanomolybdate(IV) molecular frameworks, but that they also belong to an unknown structure type having seven different nodes. To the best of our knowledge this is different to any other known molybdenum(IV) octacyanide complexes published to date. Both compounds crystallize in the triclinic system, space group P-1, and are isostructural and isotypic. The coordination polyhedra of the molybdenum atoms in the three different [Mo(CN)8]4− anions are trigonal prisms, with two additional atoms. A new bridging mode for octacyanometallates is also observed with five of the eight cyanide groups involved in bridging either three or four rare-earth atoms, while the three remaining cyanide groups are terminal and are involved in hydrogen bonding. The four rare-earth atoms in 1 and 2 have different coordination polyhedra in the form of trigonal prisms with two additional atoms. The three-dimensional structures are made up of infinite two-dimensional slabs linked by one of the rare-earth metal atoms. In both compounds, apart from the 17 coordinated water molecules, there are 11 lattice water molecules of crystallization present in the cavities of the three-dimensional frameworks. The 28 water molecules and the terminal CN− groups are involved in an extensive O–H⋯O and O–H⋯N hydrogen bonding network.

The role of building form in energy consumption: The case of a prismatic building in Athens

This paper examines the behaviour in energy consumption of buildings that have polygonal and prismatic envelopes and are located in Mediterranean climates. More specifically, it aims at studying the differences in energy consumption of these kinds of buildings compared to orthogonal building envelopes. For this purpose a contemporary building was chosen and modelled in two different versions, one being the original prismatic form and the other a model of the same building with right angles, however retaining all area and volume data of the original prismatic building. Calculations reveal that the prismatic formed building has lower solar gains compared to its orthogonal counterpart and consumes less energy in an annual cycle. The results show a mean annual energy consumption difference of 7.88% in favour of the prismatic building envelope. Also, depending on the orientation, the difference in annual energy needs has a range between 2.51% and 16.01%.

Numerical analyses of optical couplers for planar waveguides

AbstractThe paper presents the results of numerical analyses of optical structures realized in the form of planar waveguides made of materials with high values of the refractive index n ≈1.85. The analysed structures consist of a waveguide and input-output systems. Input-output couplers are realized in the form of prisms as well as Bragg’s grating couplers. Numerical investigations were carried out by applying the finite difference time domain (FDTD) method.

Geometría de los depósitos cuaternarios y actuales de la Bahía de Cartagena de Indias, Colombia

The description of the stratification found in the different parts of Cartagena de Indias Bay is presented by the analysis of thirteen sub-bottom transects made with a Stratabox 10 kHz sub-bottom profiler. There were zones with very hard superficial sediments that aloud little penetration in the external area off Bocagrande with layers of 10-12m of softer mud deposited over harder bases. Some deep structures are old coral reefs. Other transects present strata with steep slopes of semi-hard sediments implying old deposits handled by coastal dynamics different from the present. The southern sections show the sedimentary prism forms at the mouth of Canal del Dique in several directions.Topographic anomalies of the shelf seem to be inherited from a former coast line, controlled by structures in NNW direction that define the axes of the current bays, and for a megastructure possibly associated with Oca and Santa Marta fault systems, with an important role in the raising and evolution of the SNSM and the associate basins.

Low-Temperature Flux Growth and Upconversion Fluorescence of the Idiomorphic Hexagonal-System NaYF4 and NaYF4:Ln (Ln = Yb, Er, Tm) Crystals

Idiomorphic NaYF4 and NaYF4:Ln (Ln = Yb, Er, Tm) crystals with upconversion fluorescence were successfully grown by the NaNO3 flux cooling method at a relatively low holding temperature. The grown NaYF4 and NaYF4:Ln crystals had a hexagonal prismatic form, and their well-developed surfaces were relatively flat. TEM images indicated that the NaYF4 crystals were of good crystallinity. Their size and shape were relatively uniform, and they were poorly aggregated. The crystal phase, form, and size depended on the growth temperature and the solute concentration. In contrast, the addition of dopant ions (Yb3+, Er3+, and Tm3+) did not affect the shape, morphology, or crystallinity of the flux-grown NaYF4:Ln crystals. Additionally, the upconversion fluorescence properties of NaYF4:Ln crystals were also dependent on the type and mixture ratio (i.e., starting composition) of the dopants. The green, orange, and blue upconversion fluorescences of NaYF4:10%Yb,1%Er, NaYF4:50%Yb,1%Er, and NaYF4:10%Yb,1%Tm crystals, resp...

Analysis of the repulsive force of highly coercive permanent magnets in surface magnetic clutches and plane magnetic systems

This paper gives an expression for calculation of the repulsive force of highly coercive permanent magnets in the form of rectangular prisms located in surface magnetic clutches or plane magnetic systems.

Morphology Control of an MCM-41 Single Crystal with the Novel Hexagonal Circular Bicone Form

In this paper, an MCM-41 single crystal with hexagonal circular bicone form has been observed, and the special morphology of the single crystal appears to be a combination of circular bicone and hexagonal prism forms. As far as we know, the circular bicone faces have not been reported in crystal morphologies before. The results show that the morphology of MCM-41 single crystals remains essentially the same and can grow larger via the multiple-growth method in extremely dilute ammonia solution. Moreover, the morphology of the MCM-41 crystals can be effectively modulated by adding inorganic salts (KCl, NaCl) to the synthetic system. Increasing the concentration of the salts (KCl, NaCl) in the solution can make the aspect ratio and the conical angle vary consistently.