Variation Of Design Parameters Research Articles

Single‐Material, Near‐Infrared Selective Absorber Based on Refractive Index‐Tunable Tamm Plasmon Structure

AbstractAs a powerful planar plasmonics, Tamm plasmon (TP) structures open up new possibilities for high‐efficiency photonic applications demanding high quality (Q)‐factor with scalability and spectral tunability. Despite the theoretical advantages of TP structures, TP configurations alternately stacked within limited materials and integer ranges result in thicker device sizes and still struggle to achieve ideal designs. Here, by introducing a computational model with varying design parameters, the configurations of high‐performance TPs are presented within thin scale. However, the optimized configuration is hard to be realized with limited conventional materials. In this study, the effective refractive index is tailored through porosity change to achieve optimized design parameters, resulting in high Q‐factors (≈45) and near‐unity absorptance (≈99%) for sub‐micron scale TPs (≈0.7 µm) based on single material. To verify single‐material TPs (SMTPs), the real and imaginary parts of the optical impedances are calculated, which are well matching each other, resulting in unity absorption. Using the designed structure, SMTPs are experimentally fabricated based on glancing angle deposition. As a practical demonstration, SMTPs are combined with a metal–semiconductor–metal photodetector as an ultra‐sensitive narrowband photodetector.

Comparative study of Inplane gradient cellular pattern honeycombs with Uniform compliant honeycombs

Cellular structures have gained attention in recent years due to its wide range of applications across various fields. One of its categories are the “Honeycombs”, honeycomb structures that came into existence at the end of 1930’s. The shapes of these structures are taken from nature, that is, the shape of a beehive. Honeycomb structures have a huge potential in terms of mechanical properties, enhancing the performance of structures and many other traits which have gained the attention of researchers switching from the conventional materials. This paper compares the energy absorption and stability properties of gradient honeycomb structures (with varying cell size across the width) with conventional or compliant structures (uniform cell size throughout the structure). Analysis is done on structures with “In-plane orientation” by varying design parameters. Using numerical modelling and FEA analysis in ANSYS software, the results are validated.

Effect of design strength parameters of conventional two-way singly reinforced concrete slab under concentric impact loading

Damage evaluation and performance enhancement of the structures due to ever-rising malicious sporadic explosions, accidental detonations, vehicular collisions, aircraft crashing, falling construction equipment, and rock/boulder impact from landslips are of considerable concern and thus generate sufficient interest to structural engineers and researchers. In general, the mode of damage to a structure and its degree depends upon which element(s) of the structure is subjected to such impulsive loadings, damage resistance, and energy transferred to the element(s). For a deeper understanding of the failure mode and impact resistance, analysis of the structural elements under impulsive loadings (blast and impact) with varying design parameters seems necessary. The present work undertakes a numerical study to investigate the dynamic behavior of 1000 mm × 1000 mm × 75 mm two-way square singly reinforced concrete slab subjected to drop-weight impact loading at its centroid using a finite element method based commercial dynamic computer code, ABAQUS/Explicit version 6.15. The impact load is applied via a hard steel cone frustum-headed drop weight with a flat impacting face of mass 105 kg having a free-fall from a height of 2500 mm with an impacting velocity of 7.0 m/sec. Two well-known material models namely; Concrete Damage Plasticity (CDP) and Johnson-Cook (J-C) for concrete and steel, respectively, with strain rate effects have been considered. The numerical model of the slab is validated with the impact test results/observations in the open literature. Analyses have been extended to investigate the influence on the impact resistance of the slab by varying slab thickness and concrete strength without altering cover to the concrete, quantity and yield strength of the flexural steel reinforcement on the impact resistance of the slab. The slab is not provided with shear reinforcement. Three different concrete strengths (30, 40, and 50 MPa) for four slab thicknesses (75, 100, 125, and 150 mm) are considered for the parametric investigation. Results have been compared and discussed with regards to peak displacement and impact resistance of the slab.

Chameleon Swarm Algorithm Assisted Optimization of U-Slot Patch Antenna for Quad-Band Applications

Existing optimization algorithms are insufficient in the face of problems with difficult measurement functions as well as a large number of design parameters. Therefore, to achieve such challenging applications, the Chameleon swarm algorithm and its variants, which belong to the family of meta-heuristic algorithms that have not been used in any antenna optimization study before, are used together with 3 different objective functions fitted from mathematical models. Then, a U-slot antenna application with 12 different variable design parameters with resonance frequencies of 3.5 GHz, 3.7 GHz, 5.2 GHz and 5.8 GHz is considered as a multidimensional and single-objective optimization problem. In this study, first of all, the success of the algorithm is reinforced by comparing the performance with other commonly used single and multi-objective optimization algorithms. In addition, the results obtained with different population parameters, weight coefficients, objective functions and variant models were compared. All these processes are compared within themselves, and the antenna results of the most successful result are displayed as 3D electromagnetic simulation. The results show that the optimization processes proposed for an antenna designer are a safe, practical and efficient solution for multidimensional and single-objective antenna optimization applications. In addition, any optimization problem with a large number of variable design parameters can undoubtedly be adapted to the Chameleon swarm algorithm.

Experimental investigation of performance of high-shear atomizer with discrete radial-jet fuel nozzle: mean and dynamic characteristics

The present study focuses on the performance of a novel high-shear atomizer with a discrete radial-jet fuel nozzle to overcome the constraints associated with the simplex-pressure-swirl and duplex-fuel nozzles at the high-end power demand of a gas turbine combustor. The high-shear atomizer consists of multiple inner and outer radial swirlers with interchangeable flare and fuel nozzle. The performance of the atomizer with discrete radial-jet fuel nozzle is elucidated at ALR (mass ratio of air to liquid) 14.1 through variations in geometrical design parameters of the swirl cup. The parameters of interest are the split ratio (γ), relative swirl direction of inner and outer swirler (co- and counter-rotation), flare angle (θ) and flare mixing length (η). Spray characteristics at ALR 4.72, 7.08 and 9.44 are also presented for an atomizer by freezing the geometrical design. The particle image velocimetry diagnostic technique is employed to capture the spray flow field. The non-dimensional radial (W/Df; W, radial width of CTRZ (in mm) and Df, exit diameter of flare (mm)) and axial (L/Df) sizes of the central toroidal recirculation zone and near field swirl number (SN5) of the flow are explored. Further, variations in the droplet size distribution of the atomizer across all the ALR are discussed in detail. The Sauter mean diameter across all the test cases is found to be in the range of 9–30 μm, 15–37 μm, 15–50 μm and 23–75 μm at ALR 14.1, 9.44, 7.08 and 4.72 respectively, which shows good atomization capability of the atomizer with discrete jets. The spatial distribution of the spray volume/mass in an azimuthal plane is examined in the circumferential and radial directions, which shows consistent and excellent azimuthal symmetry of the spray even with a decrease in ALR value. The overall mean and dynamic spray characteristics of the atomizer suggest that high-shear atomizer in combination with a discrete radial-jet fuel nozzle would be a better candidate than an atomizer with a simplex pressure-swirl fuel nozzle in rich-quench-lean concept-based gas turbine combustors.

A simulation-based analysis of the effects of variable prosthesis stiffness on interface dynamics between the prosthetic socket and residual limb.

Introduction: Loading of a residual limb within a prosthetic socket can cause tissue damage such as ulceration. Computational simulations may be useful tools for estimating tissue loading within the socket, and thus provide insights into how prosthesis designs affect residual limb-socket interface dynamics. The purpose of this study was to model and simulate residual limb-socket interface dynamics and evaluate the effects of varied prosthesis stiffness on interface dynamics during gait.Methods: A spatial contact model of a residual limb-socket interface was developed and integrated into a gait model with a below-knee amputation. Gait trials were simulated for four subjects walking with low, medium, and high prosthesis stiffness settings. The effects of prosthesis stiffness on interface kinematics, normal pressure, and shear stresses were evaluated.Results: Model-predicted values were similar to those reported previously in sensor-based experiments; increased stiffness resulted in greater average normal pressure and shear stress (p < 0.05).Conclusions: These methods may be useful to aid experimental studies by providing insights into the effects of varied prosthesis design parameters or gait conditions on residual limb-socket interface dynamics. The current results suggest that these effects may be subject-specific.

Multi-Body Simulation of a Novel Electrode Stacking Process for Lithium-Ion Battery Production

Stack assembly in lithium-ion battery production is limited regarding productivity. This paper presents a novel electrode stacking process with a rotational handling device enabling a continuous and therefore high-throughput material flow. The design parameters of the handling device and the peripherals influence the stacking process, but their correlations are unknown so far. To examine the dynamics and forces acting on the electrode, a multi-body simulation of the process was conducted with variable design and process parameters. The results show significant interactions between these parameters, especially between rotational velocity of the handling unit, feeding position, and feeding rate of the electrodes.

Verification and improvement of flexible mathematical procedures for co-optimizing design and control of fuel cell hybrid vehicles

A study on the usefulness of flexible mathematical tools for determining the optimal architecture of fuel cell hybrid vehicles is presented. Starting from a pre-existing powertrain and control strategies co-optimization tool, the technological (especially in terms of lithium battery type) search domain was first expanded by including an updated battery model. Afterward, the availability of specification independent control strategies was exploited in such a way as to enable two optimization tasks: one relying on previous heuristic control rules and the other based on newly optimized control strategies. The results evidenced negligible differences, in terms of key control variable trends, objective (i.e., fuel economy), and design parameters (i.e., fuel cell system size and battery energy density), thus further proving the tool versatility. Moreover, optimal configurations exhibit appreciable fuel economies and acceleration performance on the WLTP driving cycle, while proposing potentially cost-effective solutions in terms of fuel cell system size.

Additive manufacturing enabled designs for dental applications: A conceptual study

Additive manufacturing (AM), or commonly also known as three-dimensional (3D) printing, has fundamentally changed the way products are designed and manufactured due to its freeform fabrication capabilities. As AM becomes more mainstream and accessible, it is therefore important to adopt new designs, or re-designing approaches, for existing products that would allow parts to be manufactured by these techniques. This study conceptualizes and derives new suitable designs for dental abutment connector used in dental implants and proof of concept is achieved using laser-based powder bed fusion of metals (PBF-L/M). The functionality of the design is tested using simulations by running static and cyclic loading to ensure that the new design can withstand a normal human bite force. Design optimization is also conducted by varying design parameters to achieve minimal Von Mises stresses throughout the abutment. Finally, the designs are compared using various design considerations and it is concluded that snap fit design is the most suitable for dental abutment due to ease of use and manufacturability.

SENSITIVITY OF STRENGTH, RIGID AND DYNAMIC CHARACTERISTICS OF THE CONSOLE ROTOR TO VARIATION OF DESIGN PARAMETERS

The analysis sensitivity of strength, rigid and dynamic characteristics of the console rotor to variation of design parameters in paper describes The speed of rotation of the shaft, the material of the impeller vary. The dependences of radial and axial displacements on the angular velocities of rotation and the modulus of elasticity of the impeller material are established. For objects of the type of rotary systems with a cantilever arrangement of the impeller, not one, but a set of criteria has been introduced into consideration, which should be taken into account in the research of this type of objects. The tendencies of change of the first and second critical rotational speeds from the modulus of elasticity, rotor rotational frequencies and density of the impeller material are also determined. On this basis, recommendations have been developed for determining the design parameters of the rotor part of the air blower with a cantilevered impeller. Keywords: air blower; critical rotation speed; natural vibration frequency; rotary system; stress-strain state

China Sponge City database development and urban runoff source control facility configuration comparison between China and the US

Urban runoff source control facilities (URSCFs) are important parts of Sponge City (SC) by controlling urban flooding, restoring eco-balance, and enhancing city resilience. To evaluate the performance of URSCF, one needs to summarize and analyze the past SC construction and operation data. Previous studies however are predominately engineering practice studies. There lacks localized reference datasets to quantitatively evaluate the performance and guide public policy development for SC. Therefore, it is imperative to develop a database, which would summarize data obtained through the already completed pilot sponge cities, and provide a reference for future URSCFs planning and construction. This study makes a zero to one breakthrough by establishing a SC database using New Orleans method. Then statistical results of facility type, size, and costs information for 30 pilot sponge cities have been summarized and analyzed. The URSCFs type distribution statistical results show that bioretention, permeable pavement, detention cell, grassed swale and constructed wetland are the top five most constructed facilities in China. The cost statistical results display that the range of facility cost collected is usually larger than the range given by the reference value, which may attribute to the variation in material cost, labor cost and design parameters in different cities. To check the similarities and differences of URSCFs parameters between China and the US. A configuration parameters comparison of URSCFs has been conducted. Bioretention is taken as an exampl. Comparison results show that factors such as climate type, geographical environment, and socio-economic conditions will affect the configuration parameters of URSCFs. The groundwater depth and designed rainfall intensity are mainly influenced by local climate and geographical conditions. Surface area is influenced by local socio-economic conditions. The thickness of the covering layer and drainage layer are not affected by geographic location. The service area ratio, water storage depth and planting soil layer thickness are significantly different between China and the US.

Определение параметров установки на пахотный агрегат дополнительных устройств для разделки почвенного пласта

Summary. This article is dedicated to the subject of designing additional tools for use with reversible ploughs that cuts and loosens topsoil. The aim is to reduce power consumption spent for soil tillage by using reversible ploughs with roller cultivators. Methods. Theoretical and experimental studies of the topsoil movement on the plough’s wing, the mouldboard and beyond. Results. Analysis of the movement of soil particles falling from the top edge of the plough’s moulboard has allowed to obtain analytical dependence for determining the size range of soil particles based on the geometry of the working surface of the plough’s body (distance from the soil surface to the top edge of the mouldboard, the angles of the edge of the mouldboard) and the kinematic parameters of the soil (speed of the plough and roller cultivator, soil particles speed on the edge of mouldboard, soil particles descent time). A research, on the movement of the soil particles, on the mouldboard surface of the plough's body is presented. The section through the mouldboard perpendicular to the wing of the plough is described by the equation of the "inverted" cycloid and based on it the dependences have been obtained to determine the kinematic parameters of the movement of the soil particles on the surface of the plough’s body, depending on the mouldboard type and properties of the soil. Results obtained in this article allow to design the roller cultivators for reversible ploughs with determined parameters of installation, in which the power consumption costs of the plowing process will be minimal. Conclusions. Obtained analytical dependences, that determine kinematic and technological parameters of the soil movement on the working surface of the plow, the section through the orthogonal wing that has the form of an "inverted"cycloid, the variable design and technological parameters of the plough and the conditions of its operation, allowing to justify the installation parameters of the roller cultivator relative to the plough, taking into account the proposed correction ratio, which depends on the mechanical properties of the soil and its structure.

The impact of variability and combined loads on fuses in braced frames

In lateral force resisting systems, fuses enable expedient repair while ensuring ductile system response. A bracing system is explored herein, in which hollow rectangular sections (RHS) and double channel sections (UPN) are used as the energy dissipating mechanism. Analyzed members have the same Eurocode section class (1st) and elastic section modulus. Loading on these fuses is a combination of bending moment, axial and shear loads (M−N−V). An analytical model is developed based on the Huber-Mises criterion to analytically describe the interaction between (M−N−V). The accuracy of the analytical model is benchmarked by a comparison with results of an experimental campaign and obtained through a finite element numerical model. The paper continues with a sensitivity analysis of the ultimate moment to the variation in axial and shear force. The analytical model is then adopted to assess how the fuse response is affected by the randomness in the design parameters (the geometrical features and mechanical properties). The impact of statistical variation in design parameters is elucidated through a Monte Carlo simulation. Variability in member geometric features was determined from current design specifications, while variability in steel mechanical properties was determined via experimental testing. The work concludes with an analysis and discussion of the Monte Carlo simulation with recommendations for designers and fabricators to encourage higher quality control in manufacturing. Variability in steel yield strength was found to have the most significant impact on the brace structural response, and must be tightly controlled for to produce accurate designs.

A physical insight into variation aware minimum V DD for deep subthreshold operation of FinFET

Several ultra-low power applications, that do not require high performance, can benefit from operation at the lowest possible supply voltage. Scaling of supply voltage is an effective method to reduce the energy consumption in digital circuits. The fundamental limit for supply voltage has been established as 36 mV for planar complementary metal oxide semiconductor (CMOS) circuits based on Shannon’s channel capacity theorem. Owing to its near ideal sub-threshold characteristics, fin field effect transistor (FinFET) devices are a better fit for ultra-low voltage applications than planar devices. In this work, the fundamental limit on supply voltage for FinFET based logic circuits has been established for the first time. This theoretical limit is found to be significantly lower than the limit for planar CMOS circuits. The effect of variation of temperature and device design parameters on this fundamental limit is also explored. The analysis is extended to other logic gates such as NAND gate. Since the operation of a FinFET device in the ultra-low voltage domain is quite different from its planar counterpart, a novel physics based, semi-empirical current equation valid for supply voltage below 100 mV has been proposed for a FinFET device to calculate this fundamental limit. Such a current model is of great importance to a circuit designer because of the ease it offers for the back of the envelope calculations. The logic gates operating in this regime are then analyzed using this proposed model.

Multiscale modeling and simulation methods for electromagnetic and multiphysics problems

Multiscale modeling and simulation methods for electromagnetic and multiphysics problems

Performance analysis of a concentrated photovoltaic cell-elastocaloric cooler hybrid system for power and cooling cogeneration

A new hybrid system model comprised of a concentrated photovoltaic cell (CPC) and an elastocaloric cooler (ECC) is proposed, where the ECC is driven by the thermal energy from CPC that cannot be converted into electrical energy. Mathematical expression between the exhaust heat of CPC and the operating electric current as well as the time required for one cycle are derived. Mathematical formulas for the power output and efficiency of CPC and proposed system and the cooling rate and efficiency of ECC are specified. Calculations show that maximum energy efficiency (MEE) and maximum power density (MPD) of hybrid system are, respectively, 20.20 % and 767.47 W m−2 larger than that of the CPC alone. A variety of design parameters and operating conditions affecting the hybrid system performance are studied. Numerical calculation results show that the environmental temperature, solar irradiation, concentration ratio and cross-sectional area ratio of CPC as well as length ratio are helpful to improve the hybrid system performance. The results obtained are helpful to optimally design and run such a real CPC/ECC hybrid system.

A comparative study review: The performance of Savonius-type rotors

The utilization of renewable energy harvesting equipment is one of the methods to reduce the level of environmental pollution risks to the world. Water and wind are considered as environmental potential resources which have become attractive features of urban utilization through different wind and hydrokinetic turbine design technology. While no large-scale Savonius turbines have been developed yet, one of the popular designs is the small-scale rotor, which utilizes a drag-based vertical axis. The advantages of this type of rotor are easy to design, inexpensive, perform well at low speed, and have the capacity to turn independently to the wind-water direction flow. However, through a number of investigations on the performance the Savonius rotor, it was found to suffer from inefficient operation and a large amount of negative torques produced by the returning blade. To resolve the limitations in performance of the Savonius turbine, many optimization techniques and assessments have been conducted on different rotor types. The studies presented and discussed the challenges and changes in variations of rotor design parameters and their significant influence on rotor performance. In order to increase the unit's output without extra cost, improving variable parameters and reducing torques were accomplished in the negative direction while decreasing maintenance cost. Hence, the data collected were classified based on geometric and installation aspect parameters, and different optimization studies were summarized based on several influencing parameters.

A Computational Gait Model With a Below-Knee Amputation and a Semi-Active Variable-Stiffness Foot Prosthesis.

Simulations based on computational musculoskeletal models are powerful tools for evaluating the effects of potential biomechanical interventions, such as implementing a novel prosthesis. However, the utility of simulations to evaluate the effects of varied prosthesis design parameters on gait mechanics has not been fully realized due to the lack of a readily-available limb loss-specific gait model and methods for efficiently modeling the energy storage and return dynamics of passive foot prostheses. The purpose of this study was to develop and validate a forward simulation-capable gait model with lower-limb loss and a semi-active variable-stiffness foot (VSF) prosthesis. A seven-segment 28-DoF gait model was developed and forward kinematics simulations, in which experimentally observed joint kinematics were applied and the resulting contact forces under the prosthesis evolved accordingly, were computed for four subjects with unilateral below-knee amputation walking with a VSF. Model-predicted resultant ground reaction force (GRFR) matched well under trial-specific optimized parameter conditions (mean R2: 0.97, RMSE: 7.7% body weight (BW)) and unoptimized (subject-specific, but not trial-specific) parameter conditions (mean R2: 0.93, RMSE: 12% BW). Simulated anterior-posterior center of pressure demonstrated a mean R2 = 0.64 and RMSE = 14% foot length. Simulated kinematics remained consistent with input data (0.23 deg RMSE, R2 > 0.99) for all conditions. These methods may be useful for simulating gait among individuals with lower-limb loss and predicting GRFR arising from gait with novel VSF prostheses. Such data are useful to optimize prosthesis design parameters on a user-specific basis.

Service Life Evaluation for RC Sewer Structure Repaired with Bacteria Mixed Coating: Through Probabilistic and Deterministic Method.

Since a concrete structure exposed to a sulfate environment is subject to surface ion ingress that yields cracking due to concrete swelling, its service life evaluation with an engineering modeling is very important. In this paper, cementitious repair materials containing bacteria, Rhodobacter capsulatus, and porous spores for immobilization were developed, and the service life of RC (Reinforced Concrete) structures with a developed bacteria-coating was evaluated through deterministic and probabilistic methods. Design parameters such protective coating thickness, diffusion coefficient, surface roughness, and exterior sulfate ion concentration were considered, and the service life was evaluated with the changing mean and coefficient of variation (COV) of each factor. From service life evaluation, more conservative results were evaluated with the probabilistic method than the deterministic method, and as a result of the analysis, coating thickness and surface roughness were derived as key design parameters for ensuring service life. In an environment exposed to an exterior sulfate concentration of 200 ppm, using the deterministic method, the service life was 17.3 years without repair, 19.7 years with normal repair mortar, and 29.6 years with the application of bacteria-coating. Additionally, when the probabilistic method is applied in the same environment, the service life was changed to 9.2–16.0 years, 10.5–18.2 years, and 15.4–27.4 years, respectively, depending on the variation of design parameters. The developed bacteria-coating technique showed a 1.47–1.50 times higher service life than the application of normal repair mortar, and the effect was much improved when it had a low COV of around 0.1.

Modelling and optimisation of a wire-plate ESP for mitigation of poultry PM emission using COMSOL

Particulate matter (PM) emissions constitute a major air pollution concern for commercial poultry production facilities. Recently, the electrostatic precipitator (ESP) has emerged as a promising technology for mitigation of poultry PM. However, further optimisation of ESP design, operation scale, and operating parameters is necessary for improved PM removal efficiencies and practical applications in poultry facilities. In this study, a comprehensive model of the poultry PM collection process in a simulated ESP module was developed using COMSOL software. The model simulated airflow characteristics, electric field and space charge development, particle charging, and particle trajectory tracking of both PM10 and PM2.5. Wire-plate ESP configurations with varying design parameters, such as number of wire electrodes and plate separation distance, were simulated using the COMSOL model at an inlet air velocity of 2.0 m s−1 to identify the optimal configuration for development of ESP physical prototypes. The model was validated by laboratory testing of a prototype ESP within a wind tunnel under three sets of ventilation conditions representing hot, warm, and cold weather, respectively. The prototype ESP exhibited PM10 collection efficiencies of 90.8%, 97.1%, and 99.0% in hot, warm, and cold weather conditions, respectively. The observed PM2.5 collection efficiencies under these respective conditions were 86.9%, 94.4%, and 97.8%. This COMSOL model can be used as an inexpensive alternative to developing physical prototypes when evaluating ESP designs for PM mitigation in poultry facilities.