Elemental Shape Research Articles

Insecticidal activity of two amorphous silica powders applied to concrete surfaces against the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae)

The increased demand for residue-free food grains has led to exploring diatomaceous earth formulations as potential alternatives to synthetic insecticides. In the present study, we evaluated the efficacy of two amorphous silica powders 1 and 2 with different elemental composition, particle diameter, and shape characteristics against the confused flour beetle, Tribolium confusum Jacquelin du Val. The insecticidal activity of the two silica powders was determined by exposing T. confusum adults to silica powder treated concrete arenas at different application rates (0, 0.5, 0.75, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, and 5.0 g/m2) for 12, 24, 36, and 48 h. Mortality assessments were made after 14 d, and adult progeny counts were made at 42 d. Silica powder 2 demonstrated greater efficacy and produced 100% adult mortality and completely inhibited adult progeny production when adults were exposed for 24 h to an application rate of 4.0 g/m2. Complete mortality and complete suppression of adult progeny production was noticed after 36 h exposure to 3.5 g/m2 of silica powder 1. Exposure of T. confusum adults to 6 g/m2 of silica powder 1 and 4 g/m2 of silica powder 2 gave complete mortality after 24 and 20 h, respectively. No adult progeny production was observed when adults were exposed for 24 h to 6 g/m2 and 4 g/m2 of silica powder 1 and silica powder 2, respectively. These findings suggest that the two silica powders hold promise for managing T. confusum, particularly in treating empty bin floors before storing new grains.

Full-field displacement and strain reconstruction for beam structures based on the extended inverse finite element method

The inverse finite element method (iFEM) is a superior shape sensing methodology in the field of structural health monitoring. However, the standard iFEM for beams yields only displacements at iFEM nodes whose spatial resolution is limited by the number of strain measurements. This study presented an extended iFEM that renders high-quality full-field displacement and strain fields by interpolating the displacements and strains at all locations on the beam using elemental shape functions. A series of numerical studies were implemented to verify the extended iFEM algorithm for various sensor and mesh configurations under different boundary and loading conditions. It showed that the extended iFEM gives smoother and more accurate results using far fewer inverse elements than the standard iFEM.

Gas Phase Reaction of Silane with Water at Different Temperatures and Supported by Plasma.

The interaction of silane and water is discussed controversially in literature: some authors suggest monosilane and water react kinetically and sufficiently fast enough to remove water, while others state the reaction occurs only at elevated temperatures. This question is of technological interest for the removal of unavoidable water residues in Ar gases. Thermodynamic calculations show that virtually complete removal of water is expected with superstoichiometric silane addition. However, mass spectrometric and infrared spectroscopic experiments give evidence that the addition of monosilane to such an Ar gas at room temperature is unable to remove residual water, which disagrees with some current hypotheses in the literature. This holds even for very high SiH4 concentrations up to 2 vol.-%. Silane reacts with water above temperatures of 555 °C, initiated by the thermal decomposition of silane. A cold dielectric barrier discharge-plasma used for silane and water dissociation enhances reactivity similar to elevated temperatures. Fourier-transformed infrared spectroscopy points toward silanol generation at temperatures between 400 and 550 °C, while quadrupole mass spectrometry indicates the creation of SiOH+, SiHOH+, SiH2OH+, and SiH3OH+. Cold plasmas generate smaller amounts of SiOH+, SiHOH+, and SiH2OH+ compared to elevated temperatures. Reaction products are hydrogen and nanoscaled particles of non-stoichiometric silicon oxides. The silicon-oxide particles produced differ in elemental composition and shape depending on the prevailing water content during decomposition: SiO x generated with residual water appears with relatively smooth surfaces, while the addition of water supports the formation of significantly rougher particle surfaces. Higher initial water contents correlate with higher oxygen contents of the particles.

Comparative study on cupric oxide nanoparticles synthesis in saline buffer versus basic water by Spondias mombin peel extract for biocatalysis

The authors herein compared the morphology, homogeneity and biocatalytic (peroxidase) activity of the synthesized cupric oxide nanoparticles (CuO NPs) from Spondias mombin peel extract for the first time in saline buffer and basic H2O system respectively. The saline buffer-assisted synthesis of CuO NPs produced homogenous and monoclinic shaped nanoparticles having excellent peroxidase activity compared to basic H2O. The saline buffer-assisted synthesis of CuO NPs was optimized in terms of peel extract concentration, time, and light. The study about elemental compositions, crystallinity, size and shape of CuO NPs (average size ⁓ 45 nm and monoclinic shape in PBS system) were confirmed through EDS, XRD, and SEM techniques. And the completion of CuO NPs synthesis within 5 minutes much shorter than the basic H2O system was confirmed through UV-visible studies. Finally, the saline buffer-assisted CuO NPs showed 10 times higher peroxidase activity against TMB-H2O2 system than basic H2O-system.

A spline-based FE approach to modelling of high frequency dynamics of 1-D structures

In this paper a computational methodology leading to the development of a new class of FEs, based on the application of continuous and smooth approximation polynomials, being splines, has been presented. Application of the splines as appropriately defined piecewise elemental shape functions led the authors to the formulation of a new approach for FEM, named as spFEM, where contrary to the well-known NURBS approach, the boundaries of spFEs are well-defined, exactly as it is in the case of the traditional FEM.The current approach has been computationally verified by the authors it terms of high frequency dynamics including such problems as: spectra of natural frequencies, modes of natural vibrations as well as wave propagation problems, especially in the aspect of high frequency responses, all in the case of selected problems involving one- and two-mode theories of 1-D structural elements. The applicability of the proposed approach has been evaluated and compared, in terms of calculated dynamic responses, with the results obtained by the use of well-established FEM approaches: classical FEM as well as TD-SFEM.In all cases investigated by the authors the proposed spFEM approach turned out to be the most accurate approach, free from the main drawback of the other tested FEM approaches thanks to the class of differentiability of approximation polynomials, which guarantees the absence of frequency band gaps in calculated spectra of natural frequencies. A direct consequence of this feature of the proposed approach is that a larger part of the calculated spectra of natural frequency, the same as modes of natural vibrations, can effectively be used for more accurate calculations of dynamic reposes even in the case of multi-mode theories. This in contrast to the other tested FEM approaches.

Investigation of shape memory characteristics and production of HfZrTiFeMnSi high entropy alloy by mechanical alloying method

High entropy alloy (HEA) with shape memory effect (SME) has been the subject of great interest for the past few decades. However, with the increased demands for new materials for high thermal applications, the research activities on the multi elemental high entropy shape memory alloys (HESMA) have been increased by many folds recently. The nano crystalline HEA powder with shape memory effect developed in this study, HfZrTiFeMnSi, was produced by mechanical alloying (MA) for the first time. In this method equiatomic ratio of Hf, Zr, Ti, Fe, Mn, and Si were mixed together and milled by MA process for 100 h. The powder formed was of amorphous in nature. Elemental mapping of the powder from SEM-EDS revealed homogeneity of the alloying elements confirming successful fabrication of HfZrTiFeMnSi HEA powder. The DSC studies from ambient to 500 °C of the annealed alloy powders showed reversible austenitic to martensitic (A↔M) transformations. The A↔M transformation hysteresis seemed to vary with the milling time and annealing temperature. The enthalpy values, ΔH, for the transformation were calculated from the DSC plots using tangent method for peak area calculation. Regardless of the annealing temperature, the thermal analysis revealed that the ΔH, equilibrium temperature (T0), and crystallization temperature values decreased with the increasing milling time.

Stock delineation of striped snakehead, Channa striata using multivariate generalised linear models with otolith shape and chemistry data

Otoliths are commonly used to discriminate between fish stocks, through both elemental composition and otolith shape. Typical studies also have a large number of elemental compositions and shape measures relative to the number of otolith samples, with these measures exhibiting strong mean–variance relationships. These properties make otolith composition and shape data highly suitable for use within a multivariate generalised linear model (MGLM) framework, yet MGLMs have never been applied to otolith data. Here we apply both a traditional distance based permutational multivariate analysis of variance (PERMANOVA) and MGLMs to a case study of striped snakehead (Channa striata) in India. We also introduce the Tweedie and gamma distributions as suitable error structures for the MGLMs, drawing similarities to the properties of Biomass data. We demonstrate that otolith elemental data and combined otolith elemental and shape data violate the assumption of homogeneity of variance of PERMANOVA and may give misleading results, while the assumptions of the MGLM with Tweedie and gamma distributions are shown to be satisfied and are appropriate for both otolith shape and elemental composition data. Consistent differences between three groups of C. striata were identified using otolith shape, otolith chemistry and a combined otolith shape and chemistry dataset. This suggests that future research should be conducted into whether there are demographic differences between these groups which may influence management considerations. The MGLM method is widely applicable and could be applied to any multivariate otolith shape or elemental composition dataset.

Temperature and elemental sulfur shape microbial communities in two extremely acidic aquatic volcanic environments.

Aquatic environments of volcanic origin provide an exceptional opportunity to study the adaptations of microorganisms to early planet life conditions. Here, we characterized the prokaryotic communities and physicochemical properties of seepage sites at the bottom of the Poas Volcano crater and the Agrio River, two geologically related extremely acidic environments located in Costa Rica. Both locations hold a low pH (1.79-2.20) and have high sulfate and iron concentrations (Fe = 47-206mg/L, SO42- = 1170-2460mg/L), but significant differences in their temperature (90.0-95.0 ºC in the seepages at Poas Volcano, 19.1-26.6 ºC in Agrio River) and in the elemental sulfur content. Based on the analysis of 16S rRNA gene sequences, we determined that Sulfobacillus spp. represented more than half of the sequences in Poas Volcano seepage sites, while Agrio River was dominated by Leptospirillum and members of the archaeal order Thermoplasmatales. Both environments share some chemical characteristics and part of their microbiota, however, the temperature and the reduced sulfur are likely the main distinguishing features, ultimately shaping their microbial communities. Our data suggest that in the Poas Volcano-Agrio River system there is a common metabolism but with specialization of species that adapt to the physicochemical conditions of each environment.

Melanic pigments and canopy-specific elemental concentration shape growth rates of the lichen Lobaria pulmonaria in unmanaged mixed forest

How do elemental composition (published data) and melanin (new data) shape the relative growth rate (RGR; new data) of the cephalolichen Lobaria pulmonaria, a member of the Lobarion community? We transplanted L.pulmonaria onto Picea glauca x engelmannii branches in three unmanaged canopy settings in inland British Columbia: within Populus dripzones supporting Lobarion; outside dripzones supporting Lobarion; and outside dripzones without Lobarion (non-Lobarion). A year later, lichen RGR was highest in the Lobarion, intermediate in the dripzone, and lowest in the non-Lobarion). RGR increased with Ca- and P-concentration, but declined with Zn, S, initial level of melaninic pigmentation, tree height, and elevation. Bark pH lost significance in multiple regression models when lichen elemental concentrations were included. Along canopy openness gradients, acclimation by the solar radiation-induced melanin had compensated for varying light. By the end of the experiment, melanin thus did not affect RGR probably because it normalized the light in the photobiont layer across sites.

Study on Transformation Mechanism and Kinetics of α’ Martensite in TC4 Alloy Isothermal Aging Process

The law of microstructure evolution and transformation mechanism of the α′ martensite decomposition during 400–600 °C were studied by the isothermal dilatometry. The transformation process of α′ martensite was quantitatively characterized based on Johnson–Mehl–Avrami (JMA) model, and the microstructure evolution under different aging processes was observed and compared on Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The results showed that α′ → α + β is the elemental diffusion transformation, the position and shape of the precipitate gradually change with the holding time and temperature. The decomposition rate of α′ martensite was positively correlated with the aging temperature. The whole transformation process was divided into two stages based on the value of the Avrami exponent n, and the corresponding average values of the transformation activation energies Q are 46.1 kJ/mol and 116.8 kJ/mol, respectively. The calculated model had good agreement with the experimental data, and the transformation curve of α′ martensite with time and temperature during the isothermal aging at 400–600 °C was drawn.

Water droplet on inclined dusty hydrophobic surface: influence of droplet volume on environmental dust particles removal.

A water droplet's behavior on an inclined hydrophobic surface in the presence of environmental dust particles is considered and the droplet's dynamics are analyzed pertinent to self-cleaning applications. A polycarbonate wafer is crystallized using the solution-crystallization method to generate hierarchically distributed micro/nano-sized spherules and pillars on the surface. To improve the wetting state and lower the contact angle hysteresis, functionalized silica particles are synthesized and, later, deposited on the crystallized surface. Environmental dust particles are collected and characterized in terms of elemental composition, size and shape. A high-speed camera is used to monitor a water droplet's behavior on the inclined hydrophobic surface with and without the presence of dust particles. The influence of droplet volume on the dust particle removal rate from the inclined hydrophobic surface is assessed. It is found that the functionalized silica particles deposited on the surface result in a droplet contact angle in the order of 158 ± 2° and contact angle hysteresis of 2 ± 1°. The water droplet mainly rolls on the inclined hydrophobic surface and the sliding velocity remains almost 13% of the transverse velocity of the droplet. Droplet wobbling is influenced by the dust particles and the droplet size; in which case, increasing the droplet volume enhances the droplet puddle thickness on the hydrophobic surface. The cloaking of the droplet fluid onto the dust particles causes mixing of the dust particles with the droplet fluid while enhancing the particle removal from the hydrophobic surface. Increasing the droplet volume slightly enhances the size of the area of the cleaned surface.

Efficient degradation of azo dye pollutants on ZnBi38O58 nanostructures under visible-light irradiation

Abstract A novel and facile approach of preparing ZnBi 38 O 58 nanostructures was developed utilizing the amino acid-assisted sol-gel combustion route. In this study, the mixtures of various gelling agents and amino acids as fuel and different molar ratios of amino acid to total metals have been employed to prepare the nanostructured ZnBi 38 O 58 with sphere-like, plate-like, cubic-like and polyhedral-like morphologies. The formation of as-synthesized nanocrystalline ZnBi 38 O 58 and its elemental composition, shape, structure and optical characteristics are analyzed utilizing UV–Vis, FESEM, FT-IR, XRD and EDS. In addition, the photocatalytic performance of as-produced ZnBi 38 O 58 nanostructures with different morphologies was studied by degradation of acid blue 92 dye as water contaminant under visible light irradiation.

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New simple route to prepare Dy2Ce2O7 nanostructures: Structural and photocatalytic studies

A novel approach of preparing nanostructured Dy2Ce2O7 was developed utilizing the simple salt-assistant combustion way. For the first time, NaCl as dispersant as well as the mixtures of succinic acid and various amino acids as fuel and capping agent have been employed to produce nanostructured Dy2Ce2O7. In this study, dysprosium nitrate and cerium(IV) ammonium nitrate were chosen as precursors. The grain size and morphology of Dy2Ce2O7 may be controlled by alteration of the kind of amino acid. The formation of as-synthesized nanocrystalline Dy2Ce2O7 and its elemental composition, shape, structure and optical characteristics are analyzed utilizing UV–vis, FESEM, FT-IR, XRD, TEM and EDS. In addition, the photocatalytic performance of as-produced nanocrystalline Dy2Ce2O7 was examined by degradation of eosin Y dye as water contaminant under ultraviolet light illumination.

Comparative study of multilayered nanostructures for enhanced solar optical absorption

ABSTRACTImproved solar spectrum optical absorption in multilayered nanostructures consisting of metal, semiconductor and dielectric layers increase their potential for efficient photon to electron conversion. In this work, we analyze the influence of different nanostructure shapes and dimensions on the optical absorption in the vacuum wavelength range of 400 nm to 1500 nm based on Finite Domain Time Difference (FDTD) method. A periodic metallic photonic crystal composed of nanorods of gold, titanium oxide, and alumina is proposed by optimizing thickness of Au and TiO2, aspect ratio, sidewall angle, and geometry of the elemental shape. A high aspect ratio structure consisting of elliptical nose cone elements with optimized dimensions is seen to absorb more than 90% of the solar spectrum in the range considered.

Biomechanical metrics of aesthetic perception in dance.

The brain may be tuned to evaluate aesthetic perception through perceptual chunking when we observe the grace of the dancer. We modelled biomechanical metrics to explain biological determinants of aesthetic perception in dance. Eighteen expert (EXP) and intermediate (INT) dancers performed développé arabesque in three conditions: (1) slow tempo, (2) slow tempo with relevé, and (3) fast tempo. To compare biomechanical metrics of kinematic data, we calculated intra-excursion variability, principal component analysis (PCA), and dimensionless jerk for the gesture limb. Observers, all trained dancers, viewed motion capture stick figures of the trials and ranked each for aesthetic (1) proficiency and (2) movement smoothness. Statistical analyses included group by condition repeated-measures ANOVA for metric data; Mann-Whitney U rank and Friedman's rank tests for nonparametric rank data; Spearman's rho correlations to compare aesthetic rankings and metrics; and linear regression to examine which metric best quantified observers' aesthetic rankings, p<0.05. The goodness of fit of the proposed models was determined using Akaike information criteria. Aesthetic proficiency and smoothness rankings of the dance movements revealed differences between groups and condition, p<0.0001. EXP dancers were rated more aesthetically proficient than INT dancers. The slow and fast conditions were judged more aesthetically proficient than slow with relevé (p<0.0001). Of the metrics, PCA best captured the differences due to group and condition. PCA also provided the most parsimonious model to explain aesthetic proficiency and smoothness rankings. By permitting organization of large data sets into simpler groupings, PCA may mirror the phenomenon of chunking in which the brain combines sensory motor elements into integrated units of behaviour. In this representation, the chunk of information which is remembered, and to which the observer reacts, is the elemental mode shape of the motion rather than physical displacements. This suggests that reduction in redundant information to a simplistic dimensionality is related to the experienced observer's aesthetic perception.

Effect of Elemental Shape and Modeling of Mixed Hybrid FEM on Numerical Solution

Mixed Hybrid Finite element method, MHF, is known to be an efficient and powerful analyzing technique with satisfactory accuracy when differentiated variables should be evaluated, such as flow velocity based on velocity potential theory or stress calculated from displacement. On the other hand, it is known that the calculation accuracy and efficiency are affected by elemental shape and modeling. The aim of this study is to confirm the efficiency and accuracy of MHF by comparing it with FEM, and to discuss optimum elemental shapes and modeling. MHF, unlike FEM, evaluates the velocity potential and the flux on the element boundaries not at the element nodes; consequently, the material or mass balance of each element due to flow-in and flow-out through the boundaries can be strictly estimated. The flow velocity within an element, however, should be interpolated by those values on the boundaries, and a distinctive shape function, known as the Raviart-Thomas shape function, becomes necessary. The authors established the MHF formulation for arbitrary shaped elements with 3 and 4 boundaries, and numerically investigated its efficiency and accuracy with various shapes of elements. Through this study, it was confirmed that MHF can evaluate accurate flow velocity with a fewer number of elements than those of FEM. In addition, the effect of shape and modeling of elements on the numerical results were discussed to obtain better accuracy even if the total number of the elements is kept constant.

Investigation of elemental shape for 3D DEM modeling of interaction between soil and a narrow cutting tool

Discrete Element Method (DEM) has been applied in recent studies of soil cutting tool interactions in terramechanics. Actual soil behavior is well known to be inexpressible by simple elemental shapes in DEM, such as circles for 2D or spheres for 3D because of the excessive rotation of elements. To develop a more effective model for approximating real soil behavior by DEM, either the introduction of a rolling resistance moment for simple elemental shape or the combination of simple elements to form a complex model soil particle shape cannot be avoided. This study was conducted to investigate the effects of elemental shape on the cutting resistance of soil by a narrow blade using 3D DEM. Six elemental shapes were prepared by combining unit spheres of equal elemental radius. Moreover, cutting resistance was measured in a soil bin filled with air-dried sand to collect comparative data. The elemental shape, with an axial configuration of three equal spheres overlapped with each radius, showed similar results of soil cutting resistance to those obtained experimentally for the six elemental shapes investigated.

Synthesis and characterisation of flower shaped Zinc Oxide nanostructures and its antimicrobial activity

Flower shaped Zinc Oxide nanostructures was synthesized using a simple method without using any structure directing agents. Elemental analysis, crystalline nature, shape and size were examined using Powder X-ray Diffraction (XRD), scanning electron microscopy (SEM), High Resolution Transmission Electron Microscopy (HRTEM) and Energy Dispersive X-ray Spectroscopy (EDAX). XRD revealed the formation of hexagonal ZnO nanostructures. SEM and TEM analyses revealed the formation of crystalline ZnO flowers in which a bunch of ZnO nanorods assembled together to form a leaf like structure followed by flower shaped ZnO nanostructures. Thus synthesised ZnO nanostructures showed good antimicrobial activity towards gram-positive bacteria Staphylococcus aureus as well as gram-negative bacteria Escherichia coli with a MIC/MBC of 25mg/L.

Comparative study of the dust particle population sampled during four consecutive campaigns in full-tungsten ASDEX Upgrade

Scanning electron microscopy images and energy-dispersive x-ray spectra were recorded for a total of about 4×104 dust particles collected on the same position within the vacuum vessel via silicon wafers during four consecutive full-tungsten first wall campaigns of ASDEX Upgrade between 2007 and 2009. By careful analysis of the elemental composition and shape of the sampled particles, seven statistically relevant classes of dust were identified. The particle flux and area coverage of each class were normalized to the total plasma duration of each sampling period, revealing a high sensitivity of the dust composition to device conditioning. According to the present results, particles produced by arcing on divertor tiles with delaminated coatings were transported to the main chamber first wall.