Influence Of Geometric Factors Research Articles

The impact of room shape on affective states, heartrate, and creative output

The architectural design of space can deeply impact an individuals' mood, physiology, and mental health. While previous research has predominantly focused on elements like nature and lighting within architectural spaces, there is a growing literature base that also investigates the psychological and neurophysiological impacts of geometrical properties of architectural spaces. Employing virtual reality technology, the study sought to investigate the effects of curved and rectangular architectural spaces on affective states, heart rate, and creativity.A total of 35 participants were exposed to two distinct virtual environments: a curved room and a rectangular room. Participants' self-reported mood was assessed using the Positive and Negative Affect Schedule (PANAS-Long Form). Heart rate was monitored using a pulse oximeter, and creative output was evaluated using the Guilford Alternative Uses Task (GAUT).Statistical comparisons between the two room types indicated that participants experienced higher positive affect and lower negative affect in the curved room condition compared to the rectangular room condition. Furthermore, heart rate measurements revealed lower physiological arousal in the curved room. Additionally, participants exhibited higher creative output in the curved room as opposed to the rectangular room.These findings align with previous literature on the influence of geometric factors on affective responses. The implications of this study are significant as they pertain to individuals' daily environments and their impact on health and well-being. The positive influence of curved room geometry on mood, arousal, and creativity emphasises the importance of considering room layout and design in various settings, such as workplaces and educational environments. Architects and designers can utilise these findings to inform their decisions and promote neuroarchitecture that enhances positive emotional experiences and productivity.

Mechanical metamaterials as broadband electromagnetic wave absorbers: investigating relationships between geometrical parameters and electromagnetic response.

The utilization of low-density and robust mechanical metamaterials rises as a promising solution for multifunctional electromagnetic wave absorbers due to their structured porous structures, which facilitates impedance matching and structural absorption. However, the various geometrical parameters involved in constructing these metamaterials affect their electromagnetic response, necessitating a comprehensive understanding of underlying absorbing mechanisms. Through experimentally validated numerical analysis, this study delves into the influence of geometrical factors on the electromagnetic response of representative low-density, high strength mechanical metamaterials, namely octet-truss and octet-foam. By juxtaposing electromagnetic response under varying volume fractions, cell lengths, and multilayer configurations of octet-truss and octet-foam, distinct absorption mechanisms emerge as geometrical parameters evolve. These mechanisms encompass diminished reflection owing to porous structures, effective medium approximations within subwavelength limits, and transmission-driven or reflection-driven phenomena originating from the interplay of open- and closed-cell structures. Through analyses on these mechanical metamaterials, we demonstrate the viability of employing them as tunable yet scalable structures that are lightweight, robust, and broadband electromagnetic wave absorption.

Influence of geometric factors on the heat transfer characteristics of two-phase thermosyphons

Thermosyphons are two-phase closed heat exchange systems that contain a certain amount of liquid and utilize the latent heat of vaporization and condensation to transfer heat between the heat source and the heat sink without any external devices. They are a type of heat pipe that lacks a capillary structure, so the return of the condensed coolant from the condensation zone to the heating zone is driven by gravitational forces. Due to the absence of a capillary structure, thermosyphons exhibit lower resistance to the movement of the vapor-liquid mixture from the heating zone to the condensation zone, as well as to the return flow of the condensate. A distinctive feature of such systems is their high equivalent thermal conductivity, which is several orders of magnitude greater than that of natural metals (such as copper or silver). Because of their superior heat transfer characteristics, thermosyphons are widely used in various technical fields, including the chemical and petroleum industries, electronics, telecommunications devices, energy storage systems, and geothermal heating systems, among others. This paper presents experimental data on the heat transfer characteristics of two-phase thermosyphons with an internal diameter of 9 mm and lengths of 500, 700, and 1000 mm, using water as the coolant. The filling ratio (Fr) varied from 0.3 to 1.2. The length of the condensation zone was the same for all thermosyphons. The study was conducted with the thermosyphons oriented vertically at an angle of 90° relative to the horizontal. The influence of the filling ratio and the effective length of the thermosyphons on the minimum thermal resistance, the maximum heat flux, and the equivalent thermal conductivity is analyzed.

Extensive investigation of geometric effects in sonoreactors: Analysis by luminol mapping and comparison with numerical predictions.

This investigation focuses on the influence of geometric factors on cavitational activity within a 20kHz sonoreactor containing water. Three vessels with different shapes were used, and the transducer immersion depth and liquid height were varied, resulting in a total of 126 experiments conducted under constant driving current. For each one, the dissipated power was quantified using calorimetry, while luminol mapping was employed to identify the shape and location of cavitation zones. The raw images of blueish light emission were transformed into false colors and corrected to compensate for refraction by the water–glass and glass-air interfaces. Additionally, all configurations were simulated using a sonoreactor model that incorporates a nonlinear propagation of acoustic waves in cavitating liquids. A systematic visual comparison between luminol maps and color-plots displaying the computed bubble collapse temperature in bubbly regions was conducted. The calorimetric power exhibited a nearly constant yield of approximately 70% across all experiments, thus validating the transducer command strategy. However, the numerical predictions consistently overestimated the electrical and calorimetric powers by a factor of roughly 2, indicating an overestimation of dissipation in the cavitating liquid model. Geometric variations revealed non-monotonic relationships between transducer immersion depth and dissipated power, emphasizing the importance of geometric effects in sonoreactor. Complex features were revealed by luminol maps, exhibiting appearance, disappearance, and merging of different luminol zones. In certain parametric regions, the luminol bright regions are reminiscent of linear eigenmodes of the water/vessel system. In the complementary parametric space, these structures either combine with, or are obliterated by typical elongated axial structures. The latter were found to coincide with an increased calorimetric power, and are conjectured to result from a strong cavitation field beneath the transducer producing acoustic streaming. Similar methods were applied to an additional set of 57 experiments conducted under constant geometry but with varying current, and suggested that the transition to elongated structures occurs above some amplitude threshold. While the model partially reproduced some experimental observations, further refinement is required to accurately account for the intricate acoustic phenomena involved.

Nonlinear thermo-elastic stability of variable stiffness curvilinear fibres based layered composite beams by shear deformable trigonometric beam model coupled with modified constitutive equations

Nonlinear thermo-elastic buckling characteristics of composite variable stiffness beam with layers making use of curvilinear fibres under thermal environment is attempted here. The model is based on a shear deformable theory introducing trigonometric function, and considering von Kármán’s assumptions based geometrical nonlinear effect. The beam constitutive equation is modified according to the stress-free situation in the width direction of beam-Poisson’s effect in the formulation for predicting the behaviour of general lay-up composite beams. By the principle of minimum total potential energy, the governing equations in terms of incremental stiffness matrices are formed introducing general beam finite element. The global equilibrium equations formulated are solved for envisaging the post-buckling path through eigenvalue analysis iteratively, thus establishing the relationship of thermal temperature against moderate amplitude level of beam deflection. A systematic parametric analysis considering different lamina properties such as curvilinear fibre path angles and including lay-up sequences, thermal expansion coefficient, mixed laminate combining straight and curvilinear fibres-based layers is carried out on thermo-structural stability of curvilinear fibre-based beams. Also, the influence of geometric factors, flexible beam end support, and variation in thermal profile, etc. over the stability behaviour of beam is examined.

Influence of layers orientation of graphene stacks in shungite disordered carbon to its integral electrical conductivity

The map of carbon distribution in the sample of graphene-containing shungite is investigated by the electron microscopy. It is found the large quantity of stacks which are formatted by parallel disposed layers of graphene. The model of electrical conductivity of graphene stack is proposed. This model takes into consideration the arbitrary orientation of layers relatively to the direction of current. It is made the numerical calculation of dependence of conductivity from the orientation of graphene layers. It is found the sharp abatement of conductivity by the orientation of graphene layers relatively to the current direction along the corner near the 45 degree. The obtained peculiarities are explained by the influence of geometrical factor.

Impact of Geometry on the Thermal and Mechanical Properties of Periodic Surface Structures: A Numerical Study

Periodic Surface Structures (PSS) fabricated via Additive Manufacturing (AM) have recently emerged as being appropriate candidates for high-value engineered structures. Among the many PSS designs, gyroid structures have demonstrated merits in mechanical properties and permeability compared to traditional lattice structures. Periodic surface structures are mathematically formulated by geometric factors: surface thickness, sample size, number of surface periods, or unit cells. These elements produce a continuous sur-face with specific topology. Numerical simulations of the effect of modulating these factors on overall thermal and mechanical properties require substantial computational resources and give a quite good qualitative assessment. Cubic P-surface (“Primitive”), D-surface (“Diamond”), and gyroid surface structures of various designs were simulated under load and heat transport using a numerical approach. The influence of geometric factors on thermal and mechanical behavior was determined qualitatively. The results show the impact of the number of cells and surface thickness on both thermal and strength modulus. The paper focuses on thermal and mechanical analysis of periodic surface structures. The study is conducted by solving the stress and heat equations using the Finite Element Method (FEM) and is achieved with the use of our authorial software. Our software module generates periodic surface structures and simulates stress and temperature distribution in it. The stress model is defined by dependence between stress and strain, it got from an experiment, and the correlation of strain and displacement got from geometric conditions. In the paper, we present calculations for three-dimensional systems in which we analyze the stress and temperature distribution depending on the geometric factors. The results presented allow estimation of the behavior of periodic surface structures under loads. It intends to evaluate the possibility of crack occurrence in complex structures based on the performed numerical simulations in future work.

A Numerical Study of Geometry's Impact on the Thermal and Mechanical Properties of Periodic Surface Structures.

The paper focuses on thermal and mechanical analysis of Periodic Surface Structure (PSS). PSS is a continuous surface with a specific topology that is mathematically formulated by geometric factors. Cubic P-surface (“primitive”), D-surface (“diamond”), and G-surface (“gyroid”) structures were simulated under load and heat transport using a numerical approach. We conducted our study by solving the stress and heat equations using the Finite Element Method (FEM). We achieved results using our software module, which generates PSS and simulates stress and temperature distribution. The stress model defined by dependence between stress and strain, gained from an experiment, and correlation of strain and displacement, gained from geometric conditions, was used in numerical experiments. The influence of geometric factors on the thermal and mechanical behavior of PSS was qualitatively determined. We showed decreasing effective stress values with an increased number of cells in the cubic domain for concerned PSS. It is important, because the increase in the number of cells does not increase the structure’s volume.

Influence of geometric factors on the efficiency of electric spark detection by a fiber sensor with a luminescent shell

Influence of geometric factors on the efficiency of electric spark detection by a fiber sensor with a luminescent shell

Effect of geometry on the mechanical properties of Ti-6Al-4V Gyroid structures fabricated via SLM: A numerical study

Triply Periodic Minimal Surface (TPMS) structures fabricated via Additive Manufacturing (AM) have recently emerged as being appropriate candidates for high-value engineered structures, including porous bio-implants and energy absorbing structures. Among the many TPMS designs, Gyroid structures have demonstrated merits in AM manufacturability, mechanical properties, and permeability in comparison to traditional lattice structures. Gyroid structures are mathematically formulated by geometric factors: surface thickness, sample size, number of surface periods, and the associated isovalue. These factors result in a continuous surface with a topology-specific structural response. Quantifying the effect of these factors on overall structural response requires substantial computational and experimental resources, and little systematic data exists in the literature. Using a numerical approach, cubic Gyroid structures of various designs were simulated under quasi-static compression, using a simulation model verified with experimental data for AM Ti-6Al-4V specimens fabricated by Selective Laser Melting (SLM). The influence of geometric factors on structural response was quantified with OFAT (One Factor At a Time) and Taguchi methods. The results identify the number of cells and surface thickness strongly influence both modulus and compressive strength. These findings were used to theoretically develop a Gyroid structure that imitates both elastic modulus and compressive strength of human cortical bone.

On Mutual Solubility in Submicron-Sized Particles of the Pt–Au Catalytic System

The equilibrium phase composition of particles in stratifying solid solutions is a parameter responsible for their catalytic activity. In this work, we used the methods of equilibrium chemical thermodynamics to consider the influence of geometric factors on phase equilibriums in submicron-sized particles with a core–shell configuration in the stratifying Pt–Au system. The particle shape and volume were specified by the effective radius and fractal dimension and used as calculation parameters. The dependence of the mutual solubility of the components on the volume and shape of submicron-sized particles was obtained, and a significant change in the region of compositions of stable solid solutions in particles of different shapes was found.

An effective thermal conductivity model for fractal porous media with rough surfaces

Quantitative evaluation of the effective thermal conductivity of porous media has received wide attention in science and engineering since it is a key thermophysical parameter in characterizing heat transfer properties. Based on fractal characters of tortuous capillary tubes and rough surfaces in micro-pores, we proposed a theoretical model of the effective thermal conductivity in porous media with rough surfaces. This model considers the geometrical parameters of porous media, including porosity, micro-pore fractal dimension, tortuosity fractal dimension, and relative roughness. The calculated normalized effective thermal conductivity was then validated against published experimental data. The results show good agreement between them. The influence of geometrical factors, porosity and relative surface roughness, on the effective thermal conductivity in porous media with rough surfaces are discussed and analyzed extensively. Cited as : Qin, X., Zhou, Y., Sasmito, A.P. An effective thermal conductivity model for fractal porous media with rough surfaces. Advances in Geo-Energy Research, 2019, 3(2): 149-155, doi: 10.26804/ager.2019.02.04

Simulations on LN2–VN2 flooding phenomenon in inclined tubes using a modified AIAD model

Simulations basing on the Eulerian multiphase model and a modified algebraic interface area density (AIAD) model are carried out to study the flooding mechanisms with liquid nitrogen (LN2) and its vapor (VN2) in an inclined pipe. The original AIAD model predicts well for the water-air flooding velocity, which assumes three flow patterns in the whole hydraulic process, including the free surface flow, bubbly flow and droplet flow. Much different flooding phenomenon for LN2-VN2 is experimentally observed by the present authors, which indicates that some parameters have to be modified for LN2-VN2 occasion. The flooding onset is mainly identified by the sharp increase of pressure drop in this paper. As expected, the modified AIAD model predicts LN2-VN2 flooding velocity with a higher accordance with experiment than before. Both the experiments and calculations show that the flooding process of LN2-VN2 goes through three stages from stratified flow to wavy flow, and finally to mist flow with the appearance of spray entrainment, which is different from the final slug flow in water-air cases. Influences of geometric factors, such as tube length and diameter, are also investigated in this research.

Investigation of the reservoir as a feeder of inclined granular flows

Hoppers or reservoirs are universally used as feeders for granular flows down inclined planes or chutes. Here we numerically investigated the influences of geometrical factors, such as inclination angles of reservoir \(\theta _{r}\) and plane \(\theta _{p}\), and the gate height H, on the granular flow. It was found if \(\theta _{r}\) is fixed and \(\theta _{p}>\theta _{r}\), there will be a little discrepancy in flow rate when the inclination angle of the plane \(\theta _{p}\) varies. Compared with the flows from tilted concentric hopper, the correlation between the flow rate and \(\theta _{r}\) in reservoir is different due to specific geometric configuration. Moreover, the flow rate obeys Beverloo’s law with various H. Additionally, the spatial fields of the inclined flows were plotted and the flow from eccentric hoppers was simulated.

Influences of geometric factors on CFD results of a draft tube cylindrical spouted bed

The effect of some geometric factors, namely, draft tube diameter and entrainment height was investigated by the two-fluid model (TFM) applying the kinetic theory of granular flow. The model proposed was found to be in a good agreement with the experimental measurements in a wide range of gas velocities and different draft tube diameters as well as entrainment heights. The influence of particle-wall restitution coefficient in the small and large draft tube diameters was examined. Accordingly, different values of ew were evaluated in the draft tubes. It was observed that the model predictions for particle behaviour through the small draft tube are sensitive to the values of ew, while the sensitivity declines and disappears for large draft tube. The particle behaviour for various geometric factors was predicted by the model.

A transfer matrix method for free vibration analysis of Euler-Bernoulli beams with variable cross section

To perform vibration analysis, many structures could be modeled entirely or partially as beams with variable or constant cross section. In this study, the differential equations for free bending vibrations of straight beams with variable cross section are solved using Bessel’s functions. Then, the general equations for one-step conical beams are used together with corresponding equations of cylindrical beams to model multi-step beams with various boundary conditions. The natural frequencies of a cantilever conical beam, calculated using its derived field matrix, were shown to be close to those obtained experimentally. In addition, the influence of geometrical factors upon the value of fundamental frequencies is investigated for both cantilever and clamped-clamped conical beams. It was shown numerically that changing a cantilever cylindrical beam into a conical beam by reducing the diameter of the free end increases its fundamental natural frequency even though its rigidity decreases. This property was not observed in a clamped-clamped conical beam. Finally, the effectiveness of a proposed transfer matrix on the calculation of natural frequencies for a multi-step beam was verified. It is believed that the current method could help in the design of various structures, including beams with variable cross section.

ВПЛИВ ГЕОМЕТРИЧНОГО ФАКТОРА НА ВІДНОВЛЕННЯ ПОВЕРХНІ ВЕЛИКОГАБАРИТНИХ ВИРОБІВ З ВИКОРИСТАННЯМ СВІТЛОДАЛЕКОМІРІВ

Проаналізовано можливості визначення координат точок поверхні великогабаритних виробів за допомогою світлодалекомірів. На прикладі вимірювальної системи з двома фазовими світлодалекомірами розглянуто вплив геометричного фактора на розрізнювальну здатність визначення координат точок поверхні. Розглянуто можливі конструкційні особливості вимірюваль-них систем, які спрямовані на зменшення дії геометричного фактора.

Influences of Geometric Factors on Rolling Force and Moment in Hot Ring Rolling of Large Parts

For hot ring rolling of large parts, rolling force and moment are of significance for designing, choosing and optimizing of rolling die and mill. In the study, the average shape parameter of the deformation zone of ring rolling is presented first, and then a reliable coupled thermo-mechanical three-dimensional (3D) finite element (FE) model for the process is developed. Finally, the influences of geometric factors on rolling force and moment during hot ring rolling of titanium alloy large parts are explored. The main results show that increasing the ratio of driver roll radius to idle roll radius or decreasing the average radius of blank is beneficial to a saving of rolling force and moment, while the axial height of blank has a little influence.

Influence factors of polarization-independent focusing by octagonal photonic quasicrystal

The focusing property of electromagnetic wave is investigated by a flat slab made of octagonal photonic quasicrystal. We obtain polarization-independent focusing by use of the all-dielectric photonic quasicrystal. The influence of geometrical factors of photonic quasicrystal on the focusing property for TM and TE polarizations is explored in detail. The results show that two orthogonal polarizations have a common focus point only under certain proper condition. Our results may be a useful guidance for the fabrication of lens devices capable of polarization-independent focusing by photonic quasicrystal.

Influence of geometric factors on the punching load resistance of early-age fibre reinforced shotcrete linings

Understanding the early-age properties of fibre reinforced shotcrete (FRS) is critical to the accurate estimation of the time to safe re-entry under freshly sprayed FRS linings. Previous research in the field has indicated that shear failures dominate early-age load resistance and thereby govern the performance of a lining during the first few hours after spraying. This investigation has examined the influence of several geometric variables on shear resistance in a punching mode of failure. In particular, the research has addressed the influence of the size, shape, eccentricity, and inclination of punching loads on the apparent shear strength of an early-age fibre reinforced shotcrete (FRS) lining.