Effect Of Structure Size Research Articles

Analysis of Factors That Affects the Capital Structure within Companies Included in the Index of LQ45 during 2011 - 2013

This study aims to determine the factors of ROA, Asset Structure, Sales Growth, and Firm Size affecting Capital Structure. The population in this study is the companies included in the Index LQ45 Indonesia Stock Exchange from the period 2011 to 2013, the data of a total of 270 listed companies in LQ45 during that period, only 90 corporate data that successively included in the index LQ45. The data used in this study uses secondary data from the Indonesia Stock Exchange website www.idx.co.id. In the process of data analysis and testing the assumptions of classical hypothesis testing using multiple linear regression analysis using SPSS v20.00. The results showed that partially variable ROA, Asset Structure, and Firm Size has a significant influence on the Capital Structure, Growth Sales whereas variable has no influence on the Capital Structure. Simultaneously ROA, Asset Structure, Sales Growth, and Firm Size effect on Capital Structure.

An exact solution for size-dependent frequencies of micro-beam resonators by considering the thermo-elastic coupling terms

An exact solution for vibrational frequencies of micro-beam resonators is presented by using a generalized thermo-elastic model. This model is based on a combination of the non-classical continuum theory with the non-Fourier heat conduction model. The coupled governing equations and both the classical and non-classical boundary conditions of motion are based on the modified couple stress theory which can capture the size-effects in micro-scaled structures. Then, the uncoupled governing equations are obtained through mathematical operations. The exact general solutions of dimensionless deflection, rotation and thermal moments were developed for all the boundary conditions. Finally, the frequency equation is derived by imposing suitable end conditions. In this study, numerical results are obtained for micro-beam resonators with rectangular cross-sections and two types of boundary condition, i.e., clamped-isothermal, and simply supported-isothermal, which are widely used in the micro-electromechanical systems. Findings indicate that values of dimensionless frequencies are strongly dependent on the material length scale parameter and also the thermal relaxation time. Furthermore, the free-vibration behaviors predicted by the non-Fourier and Fourier heat conduction models are completely different from each other.

Structural, energetic, and electronic properties of gyroidal graphene nanostructures

Nanostructures configured as triply periodic minimal surfaces, such as gyroidal systems, possess a broad range of potential applications as energy and storage materials and can be used as elementary building blocks for complex electronics. Here, we investigate the effect of structure size and material density on a number of sp2 carbon gyroid structures. We describe a general Monte Carlo method for discovering atomic structures of carbon gyroids of arbitrary size that obey the prescribed space group symmetry for gyroid surfaces. A total of 19 structures are investigated, among which we find three types of ground state structures corresponding to a given number of atomic cycles present in the asymmetric unit cell. Each type is characterized by the distribution of non-hexagonal rings: type I structures present a minimum number of non-hexagonal rings (octagons), while type II (type III) structures include square and heptagon (pentagons and octagons) in addition to hexagons. We use density functional theory to establish how electronic, topological, geometric, and energetic properties of these gyroids vary with size and density. We determine that most studied systems feature occupied and unoccupied three-dimensional Dirac hyper-cones and metallic and semi-conducting behaviors.

Size effect in Paris law and fatigue lifetimes for quasibrittle materials: Modified theory, experiments and micro-modeling

Unlike brittle materials, quasibrittle materials exhibit a structure size effect on the fatigue crack growth rate, particularly on the Paris law coefficient (prefactor). This size effect is strong for specimens not much larger than the dominant material inhomogeneities (or aggregate sizes in concrete), and vanishes for very large structures. It can be quantified by a size adjustment of Paris law which is similar to the size effect law for monotonic loading. But the transitional size D0c at which the transition is centered is not the same. Previous experiments aimed at quantitative analysis of this size effect involved only one or a few specimens per size. Thus the huge scatter, inevitable in fatigue tests, distorted the estimates of D0c and, thereby, also of the size of the cyclic fracture process zone (FPZ), to which D0c is proportional. Here, more reliable estimates of D0c and the cyclic FPZ size are obtained by conducting, on concrete, multiple fatigue tests per size and taking the average. Furthermore, these length characteristics are also estimated numerically using the latest version of the microplane constitutive damage model for concrete (model M7), extended to quasibrittle fatigue. It is conclusively shown that the cyclic FPZ is smaller than the monotonic FPZ. Further, the numerical simulations of the cyclic deformations within the FPZ reveal that the D0c obtained from the previous form of the size-adjusted Paris law is not proportional to the cyclic FPZ size. A new form is proposed and verified by updated dimensional analysis. It involves the transitional sizes for both the monotonic and cyclic size effects and is seen to yield values of D0c that are proportional to the cyclic FPZ size. The ensuing size effect on fatigue lifetimes is simulated using both the previous and new forms. Both forms are found to predict a non-monotonic size effect on the lifetimes, initially decreasing and, after a minimum, eventually increasing with increasing size. It is also shown that, similar to Paris law for brittle fatigue, an extension to the fatigue threshold at nearly vanishing amplitude is impossible because of a transition to Charles–Evans law for static fatigue. Finally, a possible ramification to fatigue of micrometer-scale metallic devices is pointed out.

Size-dependent geometrically nonlinear free vibration analysis of fractional viscoelastic nanobeams based on the nonlocal elasticity theory

In recent decades, mathematical modeling and engineering applications of fractional-order calculus have been extensively utilized to provide efficient simulation tools in the field of solid mechanics. In this paper, a nonlinear fractional nonlocal Euler–Bernoulli beam model is established using the concept of fractional derivative and nonlocal elasticity theory to investigate the size-dependent geometrically nonlinear free vibration of fractional viscoelastic nanobeams. The non-classical fractional integro-differential Euler–Bernoulli beam model contains the nonlocal parameter, viscoelasticity coefficient and order of the fractional derivative to interpret the size effect, viscoelastic material and fractional behavior in the nanoscale fractional viscoelastic structures, respectively. In the solution procedure, the Galerkin method is employed to reduce the fractional integro-partial differential governing equation to a fractional ordinary differential equation in the time domain. Afterwards, the predictor–corrector method is used to solve the nonlinear fractional time-dependent equation. Finally, the influences of nonlocal parameter, order of fractional derivative and viscoelasticity coefficient on the nonlinear time response of fractional viscoelastic nanobeams are discussed in detail. Moreover, comparisons are made between the time responses of linear and nonlinear models.

Influence of deformation on metal structure in the forward microextrusion process

Investigation results presented in the work relates to the impact of tool roughness on the material plastic flow during forward microextruding of metal. Investigation process consists of the experimental and numerical parts. In the experimental one, forward microextrusion of annealed material using the toolkit author’s copyright project were performed. The tests were conducted to compare deformation of the material extruded in containers with different roughness. As a results, obtained images of deformed material structures are presented and compared. Numerical part relates to simulations of analogous microextrusion processes conducted using DEFORM software. Tool roughness were modeled in the form of rigid triangular waves, whose geometric parameters are based on the roughness profiles obtained for the experimental tools. Depth and length of the triangular elements were determined using the motives method. Distribution fields of the effective stress, strain and the flow velocities are presented and compared. Based on obtained data, concept of determining of the parameter which can help to define the appearance of structural size effect resulting from the influence of container roughness is also presented. DOI: http://dx.doi.org/10.5755/j01.mech.21.4.9553

Pengaruh Struktur Kepemilikan, Ukuran Komite Audit dan Kualitas Audit Terhadap Luas Pengungkapan Kompensasi Manajemen Kunci di Laporan Keuangan

The purpose of this study is to investigate the effect of ownership structure and audit committee's size to the disclosure of executive management compensation in the Financial Statement. The research 's samples are 125 manufacturing companies that listed in Indonesia Stock Exchange in 2012. The results of this research show that managerial ownership and audit committee's size does not have a significant effect to the disclosure of executive management compensation in the Financial Statements. Besides that, institutional ownership has a negative significant effect to the disclosure of executive management compensation in the Financial Statements.

Structural, magnetic behaviors and temperature-dependent Raman scattering spectra of Y and Zr codoped BiFeO3 ceramics

Multiferroic [Formula: see text] (BFO) and Y, Zr codoped BFO [Formula: see text] ceramics were prepared and the influence of codoping on the crystal structure and magnetic properties were investigated in this work. Confirmed by the evolution of X-ray diffraction and Raman modes, the codoping has changed the crystal structure from rhombohedral to tetragonal in bulk BFO ceramics. The enhancement of magnetic behaviors is demonstrated by the damage of space-modulated spiral spin structure, and it can be attributed to the crystal structure change and size effects. Meanwhile, Raman spectra from 300 to 800 K demonstrates that lower frequency phonon modes show rapid softening near the Neel temperature.

Effect of Pore Structure on the Electro-Fenton Activity of ACF@OMC Cathode

Electro-Fenton is a promising advanced oxidation process for wastewater treatment. In this study, mesoporous carbon grafted activated carbon fibers (ACF@OMC) with different pore size were fabricated by using boric acid as the expanding agent. To study the pore structure and pore size effect on the electro-Fenton (E-Fenton) efficiency of ACF@OMC cathode materials, disordered mesoporous carbon grafted activated carbon fibers (ACF@DMC) were also prepared, and both anionic dye (Orange II) and cationic dye (Rhodamine B) were selected as target organic pollutants. Meanwhile, electro-induced generation rates of hydrogen peroxide and hydroxyl radical were measured. It was found that the E-Fenton efficiency of the cathode materials follows the increasing order of ACF@DMC < ACF@OMC-3.7 < ACF@OMC-5.4. Even after 10 consecutive experiments, the reactivity of ACF@OMC-5.4 cathode materials almost remained unchanged, indicating its promising application in practical wastewater treatment. This study gives new insights in...

Optical absorption properties and control method of nanostructures

Due to the localized surface plasmon resonance (LSPR) effect excited at the nanostructure surface, plasmonic nanostructures have strong scattering and absorption properties, which have important applications in photothermal conversion, photochemical conversion, photoelectric conversion, and so on. Compared to single-material nanoparticles, core/shell plasmonic composite nanoparticles have unique optical properties. The plasmon resonance features are strongly affected by nanoparticle size, shape, layer thickness, and the surrounding medium. In this study, Ag-core/SiO2-shell and SiO2-core/Ag-shell nanostructures were examined, with water as the surrounding medium. The effects of structure size and layer thickness on optical absorption properties were investigated. Moreover, the differences in the optical properties between the metal/dielectric and dielectric/metal nanostructures, and the main causes of the differences, will be discussed in this paper. The optical absorption properties of core/shell plasmonic nanostructures were simulated by the finite-difference time-domain (FDTD) method. The inner and outer radii of the core/shell nanostructures were R 1 and R 2, respectively. For the Ag/SiO2 core/shell nanostructure, as outer radius R 2 increased, the absorption intensity gradually decreased, while the plasmon resonance frequency remained approximately constant. A slight change in SiO2 shell thickness could significantly affect resonance intensity, but had little effect on resonance frequency. As the LSPR effect was excited at the Ag core surface, the electric-field was strongly enhanced. The strong near-field effect enhanced light absorption and scattering. By altering the core and shell materials, forming metal-coated dielectric composite nanostructures, the optical absorption properties can be changed significantly. The SiO2-core and Ag-shell composite nanostructure was studied to investigate the effect of nanostructure parameters on optical absorption properties. The metal shell thickness has a great influence on the resonance features. A little change in the Ag shell thickness can lead to a great shift of the plasmon resonance peak. As the metal shell thickness increased, the resonance frequency gradually shifted to shorter wavelengths, and the resonance intensity weakened. This indicates that the metal shell thickness plays an important role in tuning the plasmon resonance features. The electric-field and energy density are much stronger in the dielectric-core/metal-shell composite nanostructure than in the metal-core/dielectric-shell composite nanostructure. By controlling the relative thicknesses of the core and shell layers, the absorption peak can be tuned to desired wave bands. Thus, the absorption band will be broadened by combining nanostructures of different sizes.

Exploring hardness enhancement in superhard tungsten tetraboride-based solid solutions using radial X-ray diffraction

In this work, we explore the hardening mechanisms in WB4-based solid solutions upon addition of Ta, Mn, and Cr using in situ radial X-ray diffraction techniques under non-hydrostatic pressure. By examining the lattice-supported differential strain, we provide insights into the mechanism for hardness increase in binary solid solutions at low dopant concentrations. Speculations on the combined effects of electronic structure and atomic size in ternary WB4 solid solutions containing Ta with Mn or Cr are also included to understand the extremely high hardness of these materials.

Mechanical Response of Hollow Metallic Nanolattices: Combining Structural and Material Size Effects

Ordered cellular solids have higher compressive yield strength and stiffness compared to stochastic foams. The mechanical properties of cellular solids depend on their relative density and follow structural scaling laws. These scaling laws assume the mechanical properties of the constituent materials, like modulus and yield strength, to be constant and dictate that equivalent-density cellular solids made from the same material should have identical mechanical properties. We present the fabrication and mechanical properties of three-dimensional hollow gold nanolattices whose compressive responses demonstrate that strength and stiffness vary as a function of geometry and tube wall thickness. All nanolattices had octahedron geometry, a constant relative density, ρ ∼ 5%, a unit cell size of 5–20 μm, and a constant grain size in the Au film of 25–50 nm. Structural effects were explored by increasing the unit cell angle from 30 deg to 60 deg while keeping all other parameters constant; material size effects were probed by varying the tube wall thickness, t, from 200 nm to 635 nm, at a constant relative density and grain size. In situ uniaxial compression experiments revealed an order of magnitude increase in yield stress and modulus in nanolattices with greater lattice angles, and a 150% increase in the yield strength without a concomitant change in modulus in thicker-walled nanolattices for fixed lattice angles. These results imply that independent control of structural and material size effects enables tunability of mechanical properties of three-dimensional architected metamaterials and highlight the importance of material, geometric, and microstructural effects in small-scale mechanics.

Use of the digital image correlation and acoustic emission technique to study the effect of structural size on cracking of reinforced concrete

An experimental investigation is performed to study the degradation of reinforced concrete beams by employing two experimental techniques simultaneously i.e. digital image correlation and acoustic emission. The former method gives very precise measurement of surface displacements, thus crack openings and crack spacing are determined. In order to complement this method and to investigate damage mechanisms, acoustic emissions resulting from internal damage are also analysed. Beams of three different sizes but proportionally similar, are tested to study the effect of structural size. A comparison of the experimental measurements with Eurocode expressions is also presented.

Simulations of wood duck recruitment from nest boxes in Mississippi and Alabama

Since the early 20th century, wildlife managers have deployed artificial nesting structures for wood ducks (Aix sponsa) to increase availability of nest sites and local reproduction of the species. However, knowledge is lacking of the effects of nest structure size (i.e., large vs. small; Stephens et al. 1998) and reproductive data (e.g., clutch size, hatch date, duckling survival) on recruitment of wood ducks. We used stochastic simulation analyses to predict recruitment of wood ducks into late summer by analyzing data from a 6-year study of box-nesting wood ducks, and 4-year (Mississippi) and 2-year (Alabama) studies of radio- marked female wood ducks and their ducklings. Our index of recruitment was the number of radio-marked ducklings per nest box that survived until 1 September. Ducklings hatched after 1 June exhibited a 30-day survival probability of 0.29, which was nearly 3 times greater than those hatched before 1 June. In east-central Mississippi, 68% and 65% of total wood duck recruits from large and small boxes, respectively, were hatched and reared from June to August. In western Mississippi, 91% of recruits from each box size also were hatched and reared from June to August. Mean number of wood duck recruits produced from large boxes was greater than small boxes at each study site; each large box in western Mississippi produced approximately 4 recruits on average, whereas small boxes in east-central Mississippi produced approximately 1 recruit. Wood duck recruits in our study resulted primarily from late spring and summer hatched birds in contrast to most Nearctic ducks with adaptive, early nesting to promote recruitment. In Mississippi and similar southern environments, we recommend use of large boxes and cleaning boxes around 1 May after completion of initial nests, and emphasize the importance of late spring and summer duckling production to wood duck recruitment. © 2015 The Wildlife Society.

Terahertz emission in ladder plus Y-configurations in double quantum dot structure.

The ladder plus Y-double quantum dot (QD) structure has been proposed to improve the second-order nonlinear susceptibility (SONS) under applied electric field. For this purpose, the wetting layer (WL) and QD inhomogeneity contribution in SONS has been considered. In addition, the structure size effect, energy level separation, momentum matrix elements, and pump detuning have been examined, and show that the SONS is increased by using the WL, a low momentum matrix element of WL-QD transition in comparison with interdot transition while QD inhomogeneity reduces SONS to half. This work is predicted to play a key role in terahertz applications, since the frequency emissions obtained are in the range of 75.5-600μm.

Adsorption Thermodynamics and Intrinsic Activation Parameters for Monomolecular Cracking of n-Alkanes on Brønsted Acid Sites in Zeolites

Experimental measurements of the rate coefficient (kapp) and apparent enthalpies and entropies of activation (ΔHapp and ΔSapp) for alkane cracking catalyzed by acidic zeolites can be used to characterize the effects of zeolite structure and alkane size on the intrinsic enthalpy and entropy of activation, ΔHint⧧ and ΔSint⧧. To determine ΔHint⧧ and ΔSint⧧, enthalpies and entropies of adsorption, ΔHads-H+ and ΔSads-H+, must be determined for alkane molecules moving from the gas phase to Brønsted acid sites at reaction temperatures (>673 K). Experimental values of ΔHapp and ΔSapp must also be properly defined in terms of ΔHads-H+ and ΔSads-H+. We report here a method for determining ΔHads-H+ and ΔSads-H+ in which the adsorption site is represented by a fixed volume that includes the proton. Values of ΔHads-H+ and ΔSads-H+ obtained from Monte Carlo simulations are in good agreement with values obtained from experimental data measured at 300–400 K. An important feature of the simulations, however, is their ability to account for the redistribution of alkane adsorbed at protons in different locations with increasing temperature. Values of ΔHint⧧ and ΔSint⧧ for the cracking of propane through n-hexane, determined from measured values of kapp and ΔHapp and simulated values of ΔHads-H+ and ΔSads-H+, agree well with values obtained independently from quantum mechanics/molecular mechanics calculations. Application of our method of analysis reveals that the observed increase in kapp with increasing n-alkane size is due primarily to a decrease in ΔHint⧧ with increasing chain length and that ΔSint⧧ is independent of chain length.

α-Al2O3 nanoslab fracture and fatigue behavior

Strain rate effects and cyclic loading behavior, relevant for fatigue initiation processes, of single crystalline α-Al2O3 nanoslab structures in vacuum have been characterized and compared under finite temperature dynamic loading and incremental static loading conditions by reactive molecular dynamics and ionic relaxation simulations, respectively. Different failure mechanisms for each loading case are observed and compared in view of known applicable material failure mechanisms. In particular, structure size effects along with unit cell and bulk defect distribution based mechanisms are considered. The effects of lateral pre-strain are assessed. Conclusions are drawn regarding conditions which could lead to low cycle failure of the material.The results indicate that finite temperature and strain rate result in lower failure strains, as compared to static relaxation calculations, however low strength enhancement of ductility with kinematic strain hardening upon repeated loading may occur. We suggest that the latter facilitates a shakedown mechanism. Positive pre-straining results in increased stress triaxiality (hydrostatic vs. equivalent stress), which significantly reduces crack healing probability, due to single sharp crack propagation. Instead, volume pre-relaxation results in multiple crack branching and/or amorphous band formation, which facilitates crack healing and deformation induced transition to purely elastic response (shakedown) possibility. Amorphization, which manifests as small strain plasticity enhancement, is found to occur ahead of propagating cracks due to multiple dislocation mechanism as a low energy barrier partially reversible low density phase transition, both at static and finite temperature/strain rate conditions. The observed property changes and phase change related defect healing mechanisms have been investigated further by bulk unit cell simulations and validated against DFT calculations.

Size effect in Paris law for quasibrittle materials analyzed by the microplane constitutive model M7

Quasibrittle materials exhibit a structure size effect on the fatigue crack growth rate, and especially in the Paris law coefficient. In previous studies, this effect was demonstrated experimentally for concrete and rock, which led to a size-adjusted Paris law for quasibrittle materials. A new length scale, viz. the transitional size for fatigue fracture, D0c, was introduced and was shown to be related to the size of the cyclic fracture process zone (FPZ). Here, the size effect is analyzed numerically by using the most recent version of the microplane constitutive damage model for quasibrittle fatigue fracture. Simulations reveal that, in contrast to earlier deductions, the cyclic FPZ size is smaller than the monotonic one. Also revealed is a discrepancy between the D0c obtained from the existing size effect hypothesis and the physical cyclic FPZ size measured from the simulations. To explain this discrepancy, a new size-adjusted Paris law is proposed and verified by updated dimensional analysis. It involves two length scales, one for the monotonic size effect, and the other for fatigue. The modified framework is seen to yield fatigue transitional size values more consistent with the cyclic FPZ size.

Bridging the gap between small scale phenomena and large scale beams strengthened with FRP – A 1D XFEM high order approach

The structural behavior, inter-laminar stresses, and potential size effect in large concrete beams strengthened with fiber reinforced polymer (FRP) composite materials are investigated. The purpose of this paper is to face the problems that arise while modeling large FRP strengthened beams (with length to thickness of the bonded layer ratio in the order of 104) due to the considerable scatter of elastic and geometrical scales. The paper develops a specially tailored finite element that combines the eXtended Finite Element Method (XFEM) along with the high order approach in order to overcome the scales problem. The capabilities and limitations of the proposed high order XFEM are then studied. The numerical study focuses on the analysis of large scale beams, compares the localized effects that evolve in such beams with the ones that evolve in small scale ones, and studies the scalability of the observations on the gap between the small scale phenomena and the size of the beam.

Improving the thermostability of β-lactoglobulin via glycation: The effect of sugar structures

This work studied the effects of sugar structure (size, position of carbonyl group, and charge state) on the thermostability of β-lactoglobulin (β-lg) when controlling the glycation extent of reducing sugars to the same level. Ribose, glucose, maltose, maltotriose, fructose and galacturonic acid were selected to react with β-lg at aw of 0.53 at 45°C for different periods to reach an average degree of saccharide attached per protein molecule β-lg (average DSP) of 5. β-Lg and the conjugates in pH3, 5 and 7 were heated. The denaturation temperature was detected by differential scanning calorimeter (DSC), and the solubility was determined by Bradford assay. The results showed that all the conjugates exhibited higher denaturation temperature than β-lg. Larger molecular size, ketose and negative charge had significant effects on increasing the denaturation temperature. β-Lg and the conjugates at pH3 and 7 could maintain their solubility when increased the temperature from 60 to 90°C. The conjugates showed better thermostability than β-lg at pH5 and sugar structure had effects on the improvement. Glycation by sugars with increasing size and negative charge stabilized β-lg. Ketose glycation did not show better thermostability than aldose, but caused more aggregates during mild or short time heating.