scholarly journals Optimal Design Methodology of Tapered Waveguide Transducers for Thickness Monitoring

Sensors ◽  
2020 ◽  
Vol 20 (7) ◽  
pp. 1892
Author(s):  
Jiuhong Jia ◽  
Yue Ren ◽  
Weiming Wang ◽  
Zuoyu Liao ◽  
Xiancheng Zhang ◽  
...  
Keyword(s):  
High Temperature ◽  
Optimal Design ◽  
Numerical Simulations ◽  
Cross Sections ◽  
Design Methodology ◽  
Wave Attenuation ◽  
Experimental Investigations ◽  
Tapered Waveguide ◽  
Solid Foundation ◽  
Shear Horizontal

For the purpose of providing transducers for long-term monitoring of wall thinning of critical pressure equipment in corrosion or high temperature environments, the optimal design methodology for tapered waveguide units was proposed in the present study. Firstly, the feasibility of the quasi-fundamental shear horizontal (SH0*) wave propagating in the tapered waveguide units was analyzed via numerical simulations, and the transmitting limitations of the non-dispersive SH0* wave were researched. Secondly, several tapered waveguide transducers with varying cross-sections to transmit pure SH0* wave were designed according to the numerical results. Experimental investigations were carried out, and the results were compared with waveguide transducers with a prismatic cross-section. It was found that the tapered waveguide units can transmit non-dispersive shear horizontal waves and suppress the wave attenuation at the same time. The experimental results agreed very well with the numerical simulations. Finally, high-temperature experiments were carried out, and the reliability of thickness measuring by the tapered waveguide transducers was validated. The errors between the measured and the true thicknesses were small. This work paves a solid foundation for the optimal design of tapered waveguide transducers for thickness monitoring of equipment in harsh environments.

Numerical Simulation of Room Airflow Using Different Closure Models and Grid Generation Schemes

2002 ◽  
Author(s):  
Anupreet Singh ◽  
Mohammad H. Hosni ◽  
Walter R. Schwarz
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Cross Sections ◽  
Heat Rate ◽  
Grid Generation ◽  
Computer Hardware ◽  
Experimental Investigations ◽  
Human Thermal Comfort ◽  
Closure Models ◽  
Technological Advances

Proper distribution of conditioned air plays an important role in both human thermal comfort and indoor air quality. Experimental investigations of airflow and temperature distributions for typical indoor environmental conditions are essential but expensive and time consuming. Technological advances in computer hardware and development of computational software in recent years have made numerical simulations of such flow conditions possible. The objectives of this study were to: (1) Evaluate the applicability of a commercial software in conducting numerical simulations of indoor airflow conditions for both isothermal and non-isothermal conditions using different turbulence closure models, and (2) Determine the effects of different grid generation techniques on the numerical results. The computations were performed for a large rectangular geometry room. Conditioned air entered the room through a high sidewall grille located on one side of the wall and exited through a return located on the opposite side of wall. All walls and ceiling were insulated. The floor was heated at a constant heat rate. This paper presents velocity, temperature, and turbulent kinetic energy profiles at various cross-sections. Good agreements between the numerical simulation results and experimental data were achieved.

OPTIMAL DESIGN OF THE NACELLE ASSEMBLY UNDER THE WING OF AN AIRLINER BASED ON RANS NUMERICAL SIMULATIONS

2015 ◽  
Vol 46 (5) ◽  
pp. 439-464
Author(s):  
Nikolay Alekseevich Zlenko ◽  
Innokentii Aleksandrovich Kursakov
Keyword(s):  
Optimal Design ◽  
Numerical Simulations

scholarly journals APPLICATION OF DOMAIN INTEGRATED DESIGN METHODOLOGY FOR BIO-INSPIRED DESIGN- A CASE STUDY OF SUTURE PIN DESIGN

2021 ◽  
Vol 1 ◽  
pp. 487-496
Author(s):  
Pavan Tejaswi Velivela ◽  
Nikita Letov ◽  
Yuan Liu ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Cross Sections ◽  
Design Methodology ◽  
Reaction Force ◽  
Integrated Design ◽  
Total Deformation ◽  
Insertion Force ◽  
Force Reaction ◽  
The Moment ◽  
Work Done

AbstractThis paper investigates the design and development of bio-inspired suture pins that would reduce the insertion force and thereby reducing the pain in the patients. Inspired by kingfisher's beak and porcupine quills, the conceptual design of the suture pin is developed by using a unique ideation methodology that is proposed in this research. The methodology is named as Domain Integrated Design, which involves in classifying bio-inspired structures into various domains. There is little work done on such bio-inspired multifunctional aspect. In this research we have categorized the vast biological functionalities into domains namely, cellular structures, shapes, cross-sections, and surfaces. Multi-functional bio-inspired structures are designed by combining different domains. In this research, the hypothesis is verified by simulating the total deformation of tissue and the needle at the moment of puncture. The results show that the bio-inspired suture pin has a low deformation on the tissue at higher velocities at the puncture point and low deformation in its own structure when an axial force (reaction force) is applied to its tip. This makes the design stiff and thus require less force of insertion.

scholarly journals Room-temperature oxygen vacancy migration induced reversible phase transformation during the anelastic deformation in CuO

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Lei Li ◽  
Guoxujia Chen ◽  
He Zheng ◽  
Weiwei Meng ◽  
Shuangfeng Jia ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxygen Vacancy ◽  
Room Temperature ◽  
High Temperature Superconductivity ◽  
Experimental Investigations ◽  
Solid State Chemistry ◽  
Vacancy Migration ◽  
Scientific Disciplines ◽  
Anelastic Deformation ◽  
Reversible Phase

AbstractFrom the mechanical perspectives, the influence of point defects is generally considered at high temperature, especially when the creep deformation dominates. Here, we show the stress-induced reversible oxygen vacancy migration in CuO nanowires at room temperature, causing the unanticipated anelastic deformation. The anelastic strain is associated with the nucleation of oxygen-deficient CuOx phase, which gradually transforms back to CuO after stress releasing, leading to the gradual recovery of the nanowire shape. Detailed analysis reveals an oxygen deficient metastable CuOx phase that has been overlooked in the literatures. Both theoretical and experimental investigations faithfully predict the oxygen vacancy diffusion pathways in CuO. Our finding facilitates a better understanding of the complicated mechanical behaviors in materials, which could also be relevant across multiple scientific disciplines, such as high-temperature superconductivity and solid-state chemistry in Cu-O compounds, etc.

Momentum exchange impact damper design methodology for object-wall-collision problems

2017 ◽  
Vol 24 (14) ◽  
pp. 3206-3218
Author(s):  
Yohei Kushida ◽  
Hiroaki Umehara ◽  
Susumu Hara ◽  
Keisuke Yamada
Keyword(s):  
Optimal Design ◽  
Design Methodology ◽  
Design Parameters ◽  
Momentum Exchange ◽  
Impact Damper ◽  
One Dimensional ◽  
Practical Design ◽  
Wall Collision ◽  
Damper Design ◽  
And Control

Momentum exchange impact dampers (MEIDs) were proposed to control the shock responses of mechanical structures. They were applied to reduce floor shock vibrations and control lunar/planetary exploration spacecraft landings. MEIDs are required to control an object’s velocity and displacement, especially for applications involving spacecraft landing. Previous studies verified numerous MEID performances through various types of simulations and experiments. However, previous studies discussing the optimal design methodology for MEIDs are limited. This study explicitly derived the optimal design parameters of MEIDs, which control the controlled object’s displacement and velocity to zero in one-dimensional motion. In addition, the study derived sub-optimal design parameters to control the controlled object’s velocity within a reasonable approximation to derive a practical design methodology for MEIDs. The derived sub-optimal design methodology could also be applied to MEIDs in two-dimensional motion. Furthermore, simulations conducted in the study verified the performances of MEIDs with optimal/sub-optimal design parameters.

Controlling the Reactivity of C60: A Theoretical Analysis of the Electronic States Modulated by Substitutional Chemistry

1994 ◽  
Vol 359 ◽  
Author(s):  
S.-H. Wang ◽  
M. Kashani ◽  
S. Jansen
Keyword(s):  
High Temperature ◽  
Theoretical Analysis ◽  
High Temperature Superconductivity ◽  
Electronic States ◽  
Experimental Investigations ◽  
Cluster Stability ◽  
Simple Substitution ◽  
Doped Materials ◽  
Multiple Species

ABSTRACTThe availability of large amounts of Buckminsterfullerene has allowed a plethora of experimental investigations on fullerenes. The chemical and physical studies have focussed on synthesis, isomerism, magnetism, spectroscopy and high temperature superconductivity in doped materials. The chemical reactivities of fullerenes have been defined and most of the studies are dominated by C60 isomers. Some of the observed activities of fullerenes parlled those of alkeies. In our previous studies, the reactivity of the 6-6' bond with respect to eco- addition was described. Current studies have exploited the olefinic nature of the 6-6' bond and analyzed the effect of the addition on cluster stability and frontier character. In this work, we describe the mechanisms of simple substitution and analyze stability and orbital effects for the addition chemistry of C60 with multiple species. Evolving changes in orbital frontier character are analyzed with respect to site directed chemistry exhibited by C60.

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