Two-dimensional Arrangement Research Articles

Behavior of Self Compacting Reinforced Concrete One Way Bubble Deck Slab

Reinforced concrete slab with plastic voids (Bubbled Deck system) is a new type of slabs which has two-dimensional arrangement of voids within the slab that is developed to decrease the slab self-weight while maintaining approximately the same load carrying capacity as compared with the solid slabs. Plastic voided slabs have the ability to reduce concrete amount by about 30 percent and this reduction is so important in terms of cost saving and enhancement the structural performance. In this research paper investigation is carried out to study the shear strength behavior of one-way bubble deck slab using self-compacting reinforced concrete. The experimental program consists of testing thirteen one-way slabs with dimensions of (1700 length, 700 width and 150 thick) mm. One of the tested slabs is a solid slab (without balls) is used as a reference, the remaining twelve bubbled slabs with ball diameter (73, 60) mm are divided into five groups according to the parameters of the experimental work, the parameters of the experimental work include: type of slab (bubble and solid slabs), ball diameter (73, 60) mm, shear reinforcement and spacing between balls. The experimental results showed that the bubbled slabs without shear reinforcement have a decrease in the ultimate load as compared to solid slab by about 3.7% to 14.3% and an increase in the deflection at ultimate load by about 10% to 22%, at the same time the first crack load decreases by about 15.3% to 42.4% as compared to solid slab due to decreases of moment of inertia of bubble slab compared to solid slab. Also, the results showed that the bubbled slabs withe shear reinforcement (multi-leg) have an increase in the ultimate load as compared to solid slab by about 35.4% to 57.3% and an increase in the deflection at ultimate load by about 1% to 15%, at the same time the first crack load decreases by about 2.8% to 27.4% as compared to solid slab.

Capacitive sensing for the detection of tile misalignment in ceramic armor arrays

The capacitive nondestructive technique uses a planar, two- or multi-terminal device to detect dielectric changes in its proximity. The technique has the advantages of being non-contact and requiring single-side access to the inspected test-piece. In this work, it is employed to determine the misalignment of ceramic tiles in two-dimensional array arrangements, as used for armored vehicles. Ceramic materials provide protection against projectile penetration in military and security applications. Tile assemblies are manufactured as protective add-on layers to armored vehicles. To provide effective protection, arrangements of rectangular or hexagonal tiles have to minimize potential misalignment, such as inter-tile gaps and out-of-plane mismatch. In this study, three planar capacitive probes with triangle-shaped terminals are used for the investigation of linear arrays of rectangular alumina tiles. Numerical simulations were employed to understand the probe's design parameters, as well as coupling aspects. It was found that the size of the capacitive probe and the separation between terminals provide a balance between spatial resolution, penetrability, and sensitivity to dielectric changes. Inter-tile gaps down to at least 0.5 mm, as well as out-of-plane tile misalignment as small as 0.25 mm were successfully discriminated.

Triggering Lewis Acidic Nature through the Variation of Coordination Environment of Cd-Centers in 2D-Coordination Polymers.

The rational design and successful synthesis of novel functional metal-organic frameworks relies on careful selection of metals and versatile organic ligands. A newly designed pyrazole-based dicarboxylate ligand, 5-(3,5-dimethyl-1H-pyrazol-1-yl) 1,3-benzenedicarboxylic acid (H2L), was utilized to obtain two new Cd-based coordination polymers I [Cd(L)(H2O)]·H2O and II [Cd(L)] under similar reaction conditions via solvothermal strategy. Single-crystal X-ray data confirmed that compound I exhibits a two-dimensional (2D) skeleton comprising pentagonal bipyramidal Cd-ions and an organic ligand moiety. Compound II has also formed a two-dimensional layer arrangement with the connectivity between trigonal bipyramidal Cd-ions and the organic ligand. Topological analysis revealed that compound I has formed unique 43.63 net topology while compound II has displayed a 44.62 sql net topology with 2D frameworks. The Lewis acidic nature of both I and II containing a Cd2+ metal center has been correlated with the coordination number through dye adsorption-desorption and catalysis studies. The selective adsorption of anionic dye and the extent of adsorption are interrelated with the Cd-ion geometry. For the first time, the role of coordinated water molecule has been analyzed through heterogeneous catalysis reaction (i.e., cyanosilylation) with Cd-based 2D-coordination polymers (CPs). The plausible mechanisms have been proposed to explain the subsequent role of coordination number and environment in CPs.

Magnetic Polymer Chains of Iron and Zwitterionic Quinoidal Ligands on the Ag(111) Surface

On-surface polymerization of iron atoms and zwitterion quinone (ZQ) molecules on Ag(111) is studied experimentally under ultra-high vacuum and theoretically in the framework of density functional theory. The resulting one-dimensional (1D) polymer chain is a promising model system to study both magnetic and conductive properties in one dimension. Previously we have shown that such polymer synthesis is possible over large scale by a controlled co-deposition of the two elements (i. e. metal and molecule) on a Ag(111) substrate (Nano Res. 2017, 10, 933). In that case, polymer chains are bound together to form a two-dimensional (2D) arrangement of spin chains influencing the magnetic properties of individual chains. Here we show that individual chains can be obtained using a sequential deposition of first metals and then ligands by scanning tunnelling microscopy on the Ag(111) surface. Ab-initio calculations are used to compare the atomic, electronic and magnetic structures of isolated Fe-ZQ polymer chains (1D...

Two-Dimensional Fluorine Distribution in a Heavily Distorted Perovskite Nickel Oxyfluoride Revealed by First-Principles Calculation

Most perovskite oxyfluorides synthesized to date have cubic structures, wherein fluorine atoms tend to reside at every oxygen site randomly. In this theoretical study, we show a two-dimensional fluorine arrangement in a perovskite nickel oxyfluoride (NdNiO2F) with a large orthorhombic distortion. The site selectivity in the perovskite lattice is due to the orthorhombicity, which stabilizes the two-dimensional cis configurations with shorter Ni–O and longer Ni–F bonds to minimize the electrostatic energy. The electronic structure of NdNiO2F is characterized by its large octahedral rotation and the higher electronegativity of fluorine than oxygen. We also observed how the anion arrangement was affected by the biaxial strain by modeling epitaxial strained thin film on substrate and found that the 2D cis structure remains the most stable. However, the orientation of the two-dimensional structure containing F depends on the magnitude of the biaxial strain. Our findings suggest that fluorine doping in orthorhom...

Macroorganisation and flexibility of thylakoid membranes.

The light reactions of photosynthesis are hosted and regulated by the chloroplast thylakoid membrane (TM) - the central structural component of the photosynthetic apparatus of plants and algae. The two-dimensional and three-dimensional arrangement of the lipid-protein assemblies, aka macroorganisation, and its dynamic responses to the fluctuating physiological environment, aka flexibility, are the subject of this review. An emphasis is given on the information obtainable by spectroscopic approaches, especially circular dichroism (CD). We briefly summarise the current knowledge of the composition and three-dimensional architecture of the granal TMs in plants and the supramolecular organisation of Photosystem II and light-harvesting complex II therein. We next acquaint the non-specialist reader with the fundamentals of CD spectroscopy, recent advances such as anisotropic CD, and applications for studying the structure and macroorganisation of photosynthetic complexes and membranes. Special attention is given to the structural and functional flexibility of light-harvesting complex II in vitro as revealed by CD and fluorescence spectroscopy. We give an account of the dynamic changes in membrane macroorganisation associated with the light-adaptation of the photosynthetic apparatus and the regulation of the excitation energy flow by state transitions and non-photochemical quenching.

Light-emitting metasurfaces

Abstract Photonic metasurfaces, that is, two-dimensional arrangements of designed plasmonic or dielectric resonant scatterers, have been established as a successful concept for controlling light fields at the nanoscale. While the majority of research so far has concentrated on passive metasurfaces, the direct integration of nanoscale emitters into the metasurface architecture offers unique opportunities ranging from fundamental investigations of complex light-matter interactions to the creation of flat sources of tailored light fields. While the integration of emitters in metasurfaces as well as many fundamental effects occurring in such structures were initially studied in the realm of nanoplasmonics, the field has recently gained significant momentum following the development of Mie-resonant dielectric metasurfaces. Because of their low absorption losses, additional possibilities for emitter integration, and compatibility with semiconductor-based light-emitting devices, all-dielectric systems are promising for highly efficient metasurface light sources. Furthermore, a flurry of new emission phenomena are expected based on their multipolar resonant response. This review reports on the state of the art of light-emitting metasurfaces, covering both plasmonic and all-dielectric systems.

Comparison of three-dimensional versus two-dimensional structure of mesoporous alumina as support of (Ni)MoS2 catalysts for HDS

Ordered mesoporous alumina (OMA), and commercial non ordered mesoporous alumina (CMA) were used as support to synthesize NiMo catalysts with a metal loading of 16%Wt. OMA synthesis was made using Pluronic (P123) as structure directing agent, and ethanol as a solvent. The physical and chemical properties of the supports and catalysts were characterized by XRD, nitrogen physisorption, X-ray photoelectron spectroscopy (XPS), Transmission electron microscopy (TEM), acidity of support was studied by n-butylamine adsorption followed by FTIR and catalytic performance was evaluated by hydrodesulphurization of dibenzothiophene (DBT) reaction. Main difference of supports is a two-dimensional arrangement of pores on OMA support and a three-dimensional arrangement for CMA. OMA support has more surface area available to disperse Mo and Ni species than the CMA material, besides OMA present slight acidity on its surface, and these characteristics of support leaded to obtain a NiMoS2 active phase better structured to present higher activity for DBT hydrodesulphurization and higher selectivity for direct desulfurization than the obtained for CMA supported catalyst, despite CMA presented interconnected pores and higher pore diameter.

An $8\times 4$ Continuous Transverse Stub Array Fed by Coaxial Ports

Continuous transverse stub arrays are wideband, wide-scanning antennas consisting of an arrangement of long slots or parallel-plate waveguide apertures radiating in free space. A line source is generally required to feed these arrays. Here, we show that such a line source can be created over the radiating aperture using a two-dimensional (2-D) arrangement of coaxial probe transitions. The coaxial transitions are directly integrated into the parallel-plate waveguides feeding the slots. Such a solution avoids using quasi-optical systems or bulky corporate networks to feed the array. The proposed 2-D feeding scheme also allows steering the main beam of the array. This is an additional benefit with respect to previous designs for which scanning was limited to a single plane. An array of 8 × 4 elements validates the concept at $\text{5.8}\,\text{GHz}$ . Measurements show that the array exhibits a field of view of $\pm{\text{30}}^\circ$ in elevation over the $\text{5.4}\text{--}\text{6.2}\,\text{GHz}$ band, with an active reflection coefficient for the central elements better than $-{\text{10 dB}}$ .

Calculation of band structures of a phononic crystal within a waveguide in 3D with cubic inclusions using a Periodic Green’s Function Method

The Phononic Crystals have generated a growing scientific interest as a means to control the dispersion of waves in various technological applications such as telecommunications. In particular, Phononic Crystal Waveguides are composed of periodic distributions of dispersers immersed in a propagation medium and, designed by an arrangement with dimensions and periods comparable to the wavelength. These crystals have properties that give them the ability to guide acoustic waves efficiently. In this paper, we present a numerical Boundary Element Method, which requires the use of a Periodic Green’s Function. This method allows to calculate the band structure of phononic crystals in two- and three-dimensions. In particular, the band structure is calculated for a waveguide formed by two flat, and parallel plates that involve a two-dimensional periodic arrangement of cubic inclusions. All surfaces involved are considered acoustic hard surfaces. The system considered, in addition to being a waveguide is in itself a phononic crystal, so that this type of systems present an alternative to manufacture to phononic crystal that can act as a phononic crystal and as an acoustic waveguide. These properties present some interest from a technological point of view.

The Importance of Electronic Dimensionality in Multiorbital Radical Conductors.

The exceptional performance of oxobenzene-bridged bis-1,2,3-dithiazolyls 6 as single-component neutral radical conductors arises from the presence of a low-lying π-lowest unoccupied molecular orbital, which reduces the potential barrier to charge transport and increases the kinetic stabilization energy of the metallic state. As part of ongoing efforts to modify the solid-state structures and transport properties of these so-called multiorbital materials, we report the preparation and characterization of the acetoxy, methoxy, and thiomethyl derivatives 6 (R = OAc, OMe, SMe). The crystal structures are based on ribbonlike arrays of radicals laced together by S···N' and S···O' secondary bonding interactions. The steric and electronic effects of the exocyclic ligands varies, affording one-dimensional (1D) π-stacked radicals for R = OAc, 1D cofacial dimer π-stacks for R = SMe, and a pseudo two-dimensional (2D) brick-wall arrangement for R = OMe. Variable-temperature magnetic and conductivity measurements reveal strong antiferromagnetic interactions and Mott insulating behavior for the two radical-based structures (R = OAc, OMe), with lower room-temperature conductivities (σRT ≈ 1 × 10-4 and ∼1 × 10-3 S cm-1, respectively) and higher thermal activation energies ( Eact = 0.24 and 0.21 eV, respectively) than found for the ideal 2D brick-wall structure of 6 (R = F), where σRT ≈ 1 × 10-2 S cm-1 and Eact = 0.10 eV. The performance of R = OMe, OAc relative to that of R = F, is consistent with the results of density functional theory band electronic structure calculations, which indicate a lower kinetic stabilization energy of the putative metallic state arising from their reduced electronic dimensionality.

Zero-Order Second Harmonic Generation from AlGaAs-on-Insulator Metasurfaces

All-dielectric metasurfaces consist of two-dimensional arrangements of nanoresonators and are of paramount importance for shaping polarization, phase, and amplitude of both fundamental and harmonic optical waves. To date, their reported nonlinear optical properties have been dominated by local features of the individual nanoresonators. However, collective responses typical of either Mie-resonant metamaterials or photonic crystals can potentially boost the control over such optical properties. In this work we demonstrate the generation of a second harmonic optical wave with zero-order diffraction, from a metasurface made out of AlGaAs-on-AlOx nanocylinders arranged with spatial period comparable to the pump telecom wavelength. Upon normal incidence of the pump beam, the modulation of Mie resonances via Bragg scattering at both fundamental and second harmonic frequencies enables paraxial second harmonic light generation by diffraction into the zero order, with a 50-fold increase in detected power within a s...

Generalized Circuit Model for Eddy Current Effects in Multi-Winding Transformers

This paper presents a novel circuit model for eddy-current effects for multi-winding transformers. It presents the theoretical framework to model eddy currents applicable to layer or disk windings with n-layers for two-dimensional (2-D) transformer arrangements. The new white-box model is physical, dual, and leakage reversible. Additionally, it does not have mutually coupled elements or negative inductors. The paper presents a complete circuit for transformer windings (including capacitances) and core. The model accurately predicts the variation of resistance (dc component, skin, and proximity effects) and leakage inductance of windings from dc to hundreds of kilohertz. Being derived from the principle of duality, the circuit elements can be physically related one-to-one to the distribution of flux and current in the winding geometry. A practical winding discretization, based on field penetration depth for the given frequency, allows estimating the parameters using very simple formulae requiring only geometrical information and properties of materials. Model verification is done using finite element simulations. It is shown that the circuit model matches very well with 2-D FEM simulations. The circuit can be easily implemented in any circuit simulation software like EMTP-RV, PSCAD, ATP, etc., by simply dragging and dropping elements.

Synthesis and physic-chemical properties of a novel chromate compound with potential biological applications, bis(2-phenylethylammonium) chromate(VI)

The structure of bis(2-phenylethylammonium) chromate (VI) (2phCr) was determined from X-ray diffraction data. The compound crystallizes in the monoclinic system (space group C2/c) with the lattice parameters: a = 38.136 (2) Å, b = 11.2334 (6) Å, c = 8.1643 (4) Å; β = 98.480 (2) V = 3459.3 (3) Å3 and Z = 8. The structure was solved from 3358 independent reflections with R = 0.034 and Rw = 0.1089. The structure consists of discrete anions (CrO42−) stacked in layers parallel to (b, c) plane at x = 1/4 and 3/4. These anions are connected to the 2-phenylethylammonium cations through NH⋯O and CH⋯O hydrogen bonds, forming a two-dimensional arrangement. Crystal structure and spectroscopic studies are reported for the 2phCr. In addition, Hirshfeld surfaces and two-dimensional fingerprint plots estimate the intermolecular interactions accountable for the generation of crystal packing. Furthermore, the title compound was screened for antibacterial activities against five pathogenic strains namely: Escherichia coli ATCC 8739, Salmonella typhimurium ATCC 14028, Staphylococus aureus ATCC 6538, Enterococcus feacium ATCC 19434 and Streptocoque B (Sreptococcus agalactiae) and antifungal activities against a clinical strain called Candida albicans ATCC 10231, corroborating significant activity. In silico investigation of bioactivity of 2phCr was performed via molecular docking analysis with four types of secreted aspartic proteinases (SAP, SAP1, SAP3, and SAP5) from Candida albicans to explore the antifungal properties in comparison to behavior of known antifungals used to treat Candida albicans, and with three types of β-ketoacyl acyl carrier protein synthase enzymes (KAS I (FabB), KAS II (FabF) and KAS III (FabH)) from Escherichia coli in comparison with that of aminothiazole, thilactomycin, and cerulerin antimicrobials. In addition, the complete assignments for 2phCr are reported considering monodentate coordination for the chromate group.

Impedance Study of Dopamine Effects after Application on 2D and 3D Neuroblastoma Cell Cultures Developed on a 3D-Printed Well

In this work, the assessment of the interactions of a bioactive substance applied to immobilized cells in either a two-dimensional (2D) or three-dimensional (3D) arrangement mimicking in vivo tissue conditions is presented. In particular, dopamine (DA) was selected as a stimulant for the implementation of an impedance analysis with a specific type of neural cells (murine neuroblastoma). The aim of this study was the extraction of calibration curves at various frequencies with different known dopamine concentrations for the description of the behavior of dopamine applied to 2D and 3D cell cultures. The results present the evaluation of the mean impedance value for each immobilization technique in each frequency. The differential responses showed the importance of the impedance when frequency is applied in both 2D and 3D immobilization cases. More specifically, in 2D immobilization matrix impedance shows higher values in comparison with the 3D cell culture. Additionally, in the 3D case, the impedance decreases with increasing concentration, while in the 2D case, an opposite behavior was observed.

Complex Dispersion Relation Recovery from 2D Periodic Resonant Systems of Finite Size

The complex dispersion relations along the main symmetry directions of two-dimensional finite size periodic arrangements of resonant or non-resonant scatterers are recovered by using an extension of the SLaTCoW (Spatial LAplace Transform for COmplex Wavenumber) method. This method relies on the analysis of the spatial Laplace transform instead of the usual spatial Fourier transform of the measured wavefield in the frequency domain. We apply this method to finite dimension square periodic arrangements of both rigid and resonant scatterers embedded in air, i.e., to finite size sonic crystals and finite size acoustic metamaterials, respectively. The main hypothesis considered in this work is the mirror symmetry of the finite structure with respect to its median axis along the analyzed direction. However, we show that the method is robust enough to provide excellent results even if this hypothesis is not fully satisfied. Effectively, a minor asymmetry could be considered as a side effect when the structure is large enough because Laplace transforming the field along the main symmetry directions also implies averaging the field in the perpendicular one. The calculated complex dispersion relations are in excellent agreement with those obtained by an already validated technique, like the Extended Plane Wave Expansion (EPWE). The methodology employed in this work is intended to be directly used for the experimental characterization of real 2D periodic and resonant systems.

Metasurface integrated with double-helix point spread function and metalens for three-dimensional imaging

Abstract Metasurfaces are two-dimensional arrangements of antennas that control the propagation of electromagnetic waves with a subwavelength thickness and resolution. Previously, metasurfaces have been mostly used to obtain the function of a single optical element. Here, we demonstrate a plasmonic metasurface that represents the combination of a phase mask generating a double-helix point spread function (DH-PSF) and a metalens for imaging. DH-PSF has been widely studied in three-dimensional (3D) super-resolution imaging, biomedical imaging, and particle tracking, but the current DH-PSFs are inefficient, bulky, and difficult to integrate. The multielement metasurface, which we label as DH-metalens, enables a DH-PSF with transfer efficiency up to 70.3% and an ultrahigh level of optical system integration, three orders of magnitude smaller than those realized by conventional phase elements. Moreover, the demonstrated DH-metalens can work in broadband visible wavelengths and in multiple incident polarization states. Finally, we demonstrate the application of the DH-metalens in 3D imaging of point sources. These results pave ways for realizing integrated DH-PSFs, which have applications in 3D super-resolution microscopy, single particle tracking/imaging, and machine vision.

Ice crystallization observed in highly supercooled confined water.

We investigate the state of water confined in the cylindrical pores of MCM-41 type mesoporous silica, with pore diameters of 2.8 nm and 4.5 nm, over the temperature range 160-290 K by combining small angle neutron scattering and wide angle diffraction. This allows us to observe simultaneously the intermolecular correlations in the local water structure (which shows up in a main water peak around Q = 1.7 Å-1), the two-dimensional hexagonal arrangement of water cylinders in the silica matrix (which gives rise to a pronounced Bragg peak around Q = 0.2 Å-1), and the so-called Porod scattering at smaller Q, which arises from larger scale interfacial scattering within the material. In the literature, the temperature evolution of the intensity of the Bragg peak has been interpreted as the signature of a density minimum in confined water at approximately 210 K. Here we show that, under the conditions of our experiment, a fraction of freezable water coexists with a layer of non-freezable water within the pore volume. The overall temperature dependence of our data in the different Q regions, as well as the comparison of the data for the two pore sizes, leads us to conclude that the observed variation in the intensity of the Bragg diffraction peak is actually caused by a liquid to ice transition in the freezable fraction of confined water.

Neutral 4-phenyl-1-[phenyl(pyridin-2-yl)methylidene]semicarbazide and its salt forms with inorganic anions.

Semicarbazones can exist in two tautomeric forms. In the solid state, they are found in the keto form. This work presents the synthesis, structures and spectroscopic characterization (IR and NMR spectroscopy) of four such compounds, namely the neutral molecule 4-phenyl-1-[phenyl(pyridin-2-yl)methylidene]semicarbazide, C19H16N4O, (I), abbreviated as HBzPyS, and three different hydrated salts, namely the chloride dihydrate, C19H17N4O+·Cl-·2H2O, (II), the nitrate dihydrate, C19H17N4O+·NO3-·2H2O, (III), and the thiocyanate 2.5-hydrate, C19H17N4O+·SCN-·2.5H2O, (IV), of 2-[phenyl({[(phenylcarbamoyl)amino]imino})methyl]pyridinium, abbreviated as [H2BzPyS]+·X-·nH2O, with X = Cl- and n = 2 for (II), X = NO3- and n = 2 for (III), and X = SCN- and n = 2.5 for (IV), showing the influence of the anionic form in the intermolecular interactions. Water molecules and counter-ions (chloride or nitrate) are involved in the formation of a two-dimensional arrangement by the establishment of hydrogen bonds with the N-H groups of the cation, stabilizing the E isomers in the solid state. The neutral HBzPyS molecule crystallized as the E isomer due to the existence of weak π-π interactions between pairs of molecules. The calculated IR spectrum of the hydrated [H2BzPyS]+ cation is in good agreement with the experimental results.

Granular ionic crystals in a small nutshell.

Ordered two-dimensional arrangements of triboelectrically oppositely charged granular particles have been reported several times, but observations of bulk ordered binary granular particle packings are singular. We attribute this suppression of triboelectrically induced order to the concurrent behaviour of granular particles to pack densest due to gravity. We show that triboelectrically induced order robustly emerges in a container that does not allow for crystallization into a dense packing under gravity. It turns out that the triboelectrically ordered structure follows Pauling's predictions for atomic ionic crystals in many aspects, but also exhibits systematic deviations. We discuss how the emergence of order in an incommensurate container, the deviations from Pauling's predictions and the gravitational potential energy of the particles are connected.