scholarly journals On the integration of acoustic phase-gradient metasurfaces in aeronautics

2020 ◽  
Vol 19 (6-8) ◽  
pp. 294-309
Author(s):  
Giorgio Palma ◽  
Lorenzo Burghignoli
Keyword(s):  
Numerical Simulations ◽  
Destructive Interference ◽  
Phase Gradient ◽  
Simulation Based Design ◽  
Simulation Based ◽  
And Control ◽  
Transformation Acoustics ◽  
Acoustic Phase ◽  
Acoustic Lining ◽  
No Absorption

Metamaterials might be one of the breakthrough technologies needed from the aeronautic industry to achieve the more and more challenging targets set by the international authorities, especially about noise emissions. In this article, a theoretical link between Transformation Acoustics and Generalized Snell’s Law, two widely used metamaterial models, is demonstrated analytically and applied to case studies. The relevance of the connection in the aeroacoustic field is discussed along with the consequent computational advantages for numerical simulations. This is exploited to perform a simulation-based design optimization of a phase-graded metasurface acoustic lining of a 2 D duct in presence of flow. Results show promising abilities of the optimized device to modify and control the directivity of the noise emitted from the duct by means of unconventional reflections. The noise reduction in the desired direction is obtained through constructive and destructive interference, with no absorption from the boundaries.

A Simulation Framework for Virtual Prototyping of Robotic Exoskeletons

2016 ◽  
Vol 138 (6) ◽  
Author(s):  
Priyanshu Agarwal ◽  
Richard R. Neptune ◽  
Ashish D. Deshpande
Keyword(s):  
Virtual Prototyping ◽  
Simulation Framework ◽  
Algorithm Optimization ◽  
Virtual Experiments ◽  
Simulation Based Design ◽  
Simulation Based ◽  
And Control ◽  
Exoskeleton Design ◽  
Systematic Framework

A number of robotic exoskeletons are being developed to provide rehabilitation interventions for those with movement disabilities. We present a systematic framework that allows for virtual prototyping (i.e., design, control, and experimentation (i.e. design, control, and experimentation) of robotic exoskeletons. The framework merges computational musculoskeletal analyses with simulation-based design techniques which allows for exoskeleton design and control algorithm optimization. We introduce biomechanical, morphological, and controller measures to optimize the exoskeleton performance. A major advantage of the framework is that it provides a platform for carrying out hypothesis-driven virtual experiments to quantify device performance and rehabilitation progress. To illustrate the efficacy of the framework, we present a case study wherein the design and analysis of an index finger exoskeleton is carried out using the proposed framework.

Simulation-Based Design of the Geometry and Control System for an Omnidirectional Ground Vehicle

2014 ◽  
Author(s):  
Li Guan ◽  
Andrew Niedert ◽  
Richard C. Hill
Keyword(s):  
Control System ◽  
Ground Vehicle ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Tightly Coupled ◽  
Physical Geometry ◽  
New Construction ◽  
Multi Body ◽  
And Control ◽  
Body Dynamic

This paper describes the simulation-based design of a teleoperated, omnidirectional ground vehicle. The multi-body dynamic simulation employed is developed in the Simulink environment, specifically employing the Simscape extension of Simulink. The accuracy of the simulation is validated by comparison to data taken from one physical instantiation of the vehicle. The use of simulation allows controlled and rapid “testing” of various configurations of the vehicle without requiring any new construction and without endangering physical hardware. The simulation also provides estimates of quantities, like road force and inertial position, that are difficult to measure. The elements of the vehicle design that are specifically investigated in this paper are the vehicle’s physical geometry and its control system. The design of the vehicle’s control system is challenging because of nonlinearities and uncertainty in the model and because it is desired to control three tightly-coupled outputs (longitudinal, lateral, and angular velocity) via six different inputs (force generated at each of the vehicle’s six wheels).

scholarly journals Investigating Preconditions for Sustainable Renewable Energy Product–Service Systems in Retail Electricity Markets

Energies ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1877
Author(s):  
Widha Kusumaningdyah ◽  
Tetsuo Tezuka ◽  
Benjamin C. McLellan
Keyword(s):  
Renewable Energy ◽  
Electricity Markets ◽  
Service Systems ◽  
Energy Market ◽  
Energy Product ◽  
Simulation Based Design ◽  
Product Service ◽  
Simulation Based ◽  
Sustainable Renewable Energy ◽  
Product Service Systems

Energy transitions are complex and involve interrelated changes in the socio-technical dimensions of society. One major barrier to renewable energy transitions is lock-in from the incumbent socio-technical regime. This study evaluates Energy Product–Service Systems (EPSS) as a renewable energy market mechanism. EPSS offer electricity service performance instead of energy products and appliances for household consumers. Through consumers buying the service, the provider company is enabled to choose, manage and control electrical appliances for best-matched service delivery. Given the heterogenous market players and future uncertainties, this study aims to identify the necessary conditions to achieve a sustainable renewable energy market. Simulation-Based Design for EPSS framework is implemented to assess various hypothetical market conditions’ impact on market efficiency in the short term and long term. The results reveal the specific market characteristics that have a higher chance of causing unexpected results. Ultimately, this paper demonstrates the advantage of implementing Simulation-Based Design for EPSS to design retail electricity markets for renewable energy under competing market mechanisms with heterogenous economic agents.

scholarly journals Optimal Scheduling for Laboratory Automation of Life Science Experiments with Time Constraints

2021 ◽  
pp. 247263032110217
Author(s):  
Takeshi D. Itoh ◽  
Takaaki Horinouchi ◽  
Hiroki Uchida ◽  
Koichi Takahashi ◽  
Haruka Ozaki
Keyword(s):  
Scheduling Algorithms ◽  
Mixed Integer ◽  
Time Constraints ◽  
Live Cells ◽  
Laboratory Automation ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Optimal Allocations ◽  
Scheduling Method ◽  
Time Required

In automated laboratories consisting of multiple different types of instruments, scheduling algorithms are useful for determining the optimal allocations of instruments to minimize the time required to complete experimental procedures. However, previous studies on scheduling algorithms for laboratory automation have not emphasized the time constraints by mutual boundaries (TCMBs) among operations, which is important in procedures involving live cells or unstable biomolecules. Here, we define the “scheduling for laboratory automation in biology” (S-LAB) problem as a scheduling problem for automated laboratories in which operations with TCMBs are performed by multiple different instruments. We formulate an S-LAB problem as a mixed-integer programming (MIP) problem and propose a scheduling method using the branch-and-bound algorithm. Simulations show that our method can find the optimal schedules of S-LAB problems that minimize overall execution time while satisfying the TCMBs. Furthermore, we propose the use of our scheduling method for the simulation-based design of job definitions and laboratory configurations.

Energy-saving design of variable-displacement bi-directional pump-controlled electrohydraulic system

2020 ◽  
pp. 095965182097389
Author(s):  
Samir Kumar Hati ◽  
Nimai Pada Mandal ◽  
Dipankar Sanyal
Keyword(s):  
Energy Saving ◽  
Absolute Error ◽  
Fast Response ◽  
Maximum Energy ◽  
Radial Clearance ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Axial Piston

Losses in control valves drag down the average overall efficiency of electrohydraulic systems to only about 22% from nearly 75% for standard pump-motor sets. For achieving higher energy efficiency in slower systems, direct pump control replacing fast-response valve control is being put in place through variable-speed motors. Despite the promise of a quicker response, displacement control of pumps has seen slower progress for exhibiting undesired oscillation with respect to the demand in some situations. Hence, a mechatronic simulation-based design is taken up here for a variable-displacement pump–controlled system directly feeding a double-acting single-rod cylinder. The most significant innovation centers on designing an axial-piston pump with an electrohydraulic compensator for bi-directional swashing. An accumulator is conceived to handle the flow difference in the two sides across the load piston. A solenoid-driven sequence valve with P control is proposed for charging the accumulator along with setting its initial gas pressure by a feedforward design. Simple proportional–integral–derivative control of the compensator valve is considered in this exploratory study. Appropriate setting of the gains and critical sizing of the compensator has been obtained through a detailed parametric study aiming low integral absolute error. A notable finding of the simulation is the achievement of the concurrent minimum integral absolute error of 3.8 mm s and the maximum energy saving of 516 kJ with respect to a fixed-displacement pump. This is predicted for the combination of the circumferential port width of 2 mm for the compensator valve and the radial clearance of 40 µm between each compensator cylinder and the paired piston.

CPI Stress Induced Carrier Mobility Shift in Advanced Silicon Nodes

2016 ◽  
Author(s):  
Valeriy Sukharev ◽  
Jun-Ho Choy ◽  
Armen Kteyan ◽  
Henrik Hovsepyan ◽  
Uwe Muehle ◽  
...  
Keyword(s):  
Electrical Characterization ◽  
Compact Modeling ◽  
Electrical Characteristics ◽  
Mobility Shift ◽  
Physical Strain ◽  
Multi Scale ◽  
Modeling Methodology ◽  
Simulation Based Design ◽  
Simulation Based ◽  
Final Design

Potential challenges with managing mechanical stress and the consequent effects on device performance for advanced 3D IC technologies are outlined. The growing need for a simulation-based design verification flow capable of analyzing and detecting across-die out-of-spec stress-induced variations in MOSFET/FinFET electrical characteristics is highlighted. A physics-based compact modeling methodology for multi-scale simulation of all contributing components of stress induced variability is described. A simulation flow that provides an interface between layout formats (GDS II, OASIS), and FEA-based package-scale tools, is also developed. This tool, can be used to optimize the floorplan for different circuits and packaging technologies, and/or for the final design signoff, for all stress induced phenomena. Finally, a calibration technique based on fitting to measured electrical characterization data is presented, along with correlation of the electrical characteristics to direct physical strain measurements.

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