Optimization of synthetic jet actuation by analytical modeling

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Max Huber ◽  
Andreas Zienert ◽  
Perez Weigel ◽  
Martin Schüller ◽  
Hans-Reinhard Berger ◽  
...  
Keyword(s):  
High Performance ◽  
Synthetic Jet ◽  
Parameter Study ◽  
Content Type ◽  
One Dimensional ◽  
Wide Range ◽  
Jet Actuators ◽  
Different Dimensions ◽  
Oscillation Correction ◽  
Good Agreement

Purpose The purpose of this paper is to analyze and optimize synthetic jet actuators (SJAs) by means of a literature-known one-dimensional analytical model. Design/methodology/approach The model was fit to a wide range of experimental data from in-house built SJAs with different dimensions. A comprehensive parameter study was performed to identify coupling between parameters of the model and to find optimal dimensions of SJAs. Findings The coupling of two important parameters, the diaphragm resonance frequency and the cavity volume, can be described by a power law. Optimal orifice length and diameter can be calculated from cavity height in good agreement with literature. A transient oscillation correction is required to get correct simulation outcomes. Originality/value Based on these findings, SJA devices can be optimized for maximum jet velocity and, therefore, high performance.

Fused filament printing of specialized biomedical devices: a state-of-the art review of technological feasibilities with PEEK

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Erfan Rezvani Ghomi ◽  
Saeideh Kholghi Eshkalak ◽  
Sunpreet Singh ◽  
Amutha Chinnappan ◽  
Seeram Ramakrishna ◽  
...  
Keyword(s):  
High Performance ◽  
State Of The Art ◽  
Three Dimensional ◽  
Patient Specific ◽  
Biomedical Devices ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Patient Specific Implants ◽  
Complex Design ◽  
Wide Range

Purpose The potential implications of the three-dimensional printing (3DP) technology are growing enormously in the various health-care sectors, including surgical planning, manufacturing of patient-specific implants and developing anatomical models. Although a wide range of thermoplastic polymers are available as 3DP feedstock, yet obtaining biocompatible and structurally integrated biomedical devices is still challenging owing to various technical issues. Design/methodology/approach Polyether ether ketone (PEEK) is an organic and biocompatible compound material that is recently being used to fabricate complex design geometries and patient-specific implants through 3DP. However, the thermal and rheological features of PEEK make it difficult to process through the 3DP technologies, for instance, fused filament fabrication. The present review paper presents a state-of-the-art literature review of the 3DP of PEEK for potential biomedical applications. In particular, a special emphasis has been given on the existing technical hurdles and possible technological and processing solutions for improving the printability of PEEK. Findings The reviewed literature highlighted that there exist numerous scientific and technical means which can be adopted for improving the quality features of the 3D-printed PEEK-based biomedical structures. The discussed technological innovations will help the 3DP system to enhance the layer adhesion strength, structural stability, as well as enable the printing of high-performance thermoplastics. Originality/value The content of the present manuscript will motivate young scholars and senior scientists to work in exploring high-performance thermoplastics for 3DP applications.

Steady Compressible Flow through a Single Row of Radial Holes in the Wall of a Pipeline

1970 ◽  
Vol 12 (4) ◽  
pp. 248-258 ◽  
Author(s):  
G. H. Trengrouse
Keyword(s):  
Discharge Coefficient ◽  
Pressure Change ◽  
Single Row ◽  
One Dimensional ◽  
Discharge Coefficients ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Flow Through ◽  
Flow Theories ◽  
Good Agreement

Measured values of discharge coefficient for air flow through a single row of radial holes in the wall of a pipeline are reported, together with the values of pipe Mach numbers in the immediate vicinity of the holes. A wide range of pressure and area ratios are considered, the flow through the holes being either into or out of the pipe. It is shown that the effects on the measured values of both the pressure level at discharge from the holes and the air temperature are negligible. The agreement between the pressure change in the pipeline due to the holes, obtained experimentally, and that predicted by simple, one-dimensional flow theories is generally unsatisfactory. However, theoretical predictions of the jet efflux angles based on two-dimensional, incompressible, non-viscous flow arguments are in good agreement with those measured, but discrepancies do arise in the prediction of discharge coefficients.

Numerical simulation of two-dimensional fins using the meshless local Petrov – Galerkin method

2020 ◽  
Vol 37 (8) ◽  
pp. 2913-2938
Author(s):  
Rajul Garg ◽  
Harishchandra Thakur ◽  
Brajesh Tripathi
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Experimental Investigation ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Content Type ◽  
One Dimensional ◽  
Mlpg Method ◽  
Convection Model ◽  
Good Agreement

Purpose The study aims to highlight the behaviour of one-dimensional and two-dimensional fin models under the natural room conditions, considering the different values of dimensionless Biot number (Bi). The effect of convection and radiation on the heat transfer process has also been demonstrated using the meshless local Petrov–Galerkin (MLPG) approach. Design/methodology/approach It is true that MLPG method is time-consuming and expensive in terms of man-hours, as it is in the developing stage, but with the advent of computationally fast new-generation computers, there is a big possibility of the development of MLPG software, which will not only reduce the computational time and cost but also enhance the accuracy and precision in the results. Bi values of 0.01 and 0.10 have been taken for the experimental investigation of one-dimensional and two-dimensional rectangular fin models. The numerical simulation results obtained by the analytical method, benchmark numerical method and the MLPG method for both the models have been compared with that of the experimental investigation results for validation and found to be in good agreement. Performance of the fin has also been demonstrated. Findings The experimental and numerical investigations have been conducted for one-dimensional and two-dimensional linear and nonlinear fin models of rectangular shape. MLPG is used as a potential numerical method. Effect of radiation is also, implemented successfully. Results are found to be in good agreement with analytical solution, when one-dimensional steady problem is solved; however, two-dimensional results obtained by the MLPG method are compared with that of the finite element method and found that the proposed method is as accurate as the established method. It is also found that for higher Bi, the one-dimensional model is not appropriate, as it does not demonstrate the appreciated error; hence, a two-dimensional model is required to predict the performance of a fin. Radiative fin illustrates more heat transfer than the pure convective fin. The performance parameters show that as the Bi increases, the performance of fin decreases because of high thermal resistance. Research limitations/implications Though, best of the efforts have been put to showcase the behaviour of one-dimensional and two-dimensional fins under nonlinear conditions, at different Bi values, yet lot more is to be demonstrated. Nonlinearity, in the present paper, is exhibited by using the thermal and material properties as the function of temperature, but can be further demonstrated with their dependency on the area. Additionally, this paper can be made more elaborative by extending the research for transient problems, with different fin profiles. Natural convection model is adopted in the present study but it can also be studied by using forced convection model. Practical implications Fins are the most commonly used medium to enhance heat transfer from a hot primary surface. Heat transfer in its natural condition is nonlinear and hence been demonstrated. The outcome is practically viable, as it is applicable at large to the broad areas like automobile, aerospace and electronic and electrical devices. Originality/value As per the literature survey, lot of work has been done on fins using different numerical methods; but to the best of authors’ knowledge, this study is first in the area of nonlinear heat transfer of fins using dimensionless Bi by the truly meshfree MLPG method.

One-dimensional inorganic semiconductor nanostructures: A new carrier for nanosensors

2010 ◽  
Vol 82 (11) ◽  
pp. 2185-2198 ◽  
Author(s):  
Xiaosheng Fang ◽  
Linfeng Hu ◽  
Changhui Ye ◽  
Lide Zhang
Keyword(s):  
High Performance ◽  
High Surface ◽  
Volume Ratio ◽  
Semiconductor Nanostructures ◽  
One Dimensional ◽  
Semiconductor Nanostructure ◽  
Research Activities ◽  
Wide Range ◽  
Inorganic Semiconductor ◽  
Art Research

One-dimensional (1D) inorganic semiconductor nanostructures have witnessed an explosion of interest over the last decade because of advances in their controlled synthesis and unique property and potential applications. A wide range of gases, chemicals, biomedical nanosensors, and photodetectors have been assembled using 1D inorganic semiconductor nanostructures. The high-performance characteristics of these nanosensors are particularly attributable to the inorganic semiconducting nanostructure high surface-to-volume ratio (SVR) and its rationally designed surface. In this review, we provide a brief summary of the state-of-the-art research activities in the field of 1D inorganic semiconductor nanostructure-based nanosensors. Some perspectives and the outlook for future developments in this area are presented.

One-Dimensional Nonlinear Parametric Instability of Inhomogeneous Plasma: Time Domain Problem

2021 ◽  
Vol 24 (3) ◽  
pp. 272-279
Author(s):  
N. V. Gerasimenko ◽  
F. M. Trukhachev ◽  
E. Z. Gusakov ◽  
L. V. Simonchik ◽  
A. V. Tomov
Keyword(s):  
Initial Conditions ◽  
Inhomogeneous Plasma ◽  
Parametric Instability ◽  
Analytical Models ◽  
Dimensional Model ◽  
One Dimensional ◽  
Proposed Model ◽  
Wide Range ◽  
Spatial And Temporal Characteristics ◽  
Good Agreement

A numerical one-dimensional model of convective parametric instability of inhomogeneous plasma is developed. By using this model, a numerical solution describing spatial and temporal characteristics of interacting waves is obtained. The results obtained are in a good agreement with known analytical models and substantially generalize them. In particular, an important advantage of the proposed model is the possibility of varying initial conditions, analyzing behavior of the system in the presence of incident wave fluctuations that is important for the future study of the absolute instability mode. The model is also provides possibility to simulate absolute parametric instability with a wide range of controllable parameters, as well as to study interacting wave transients.

scholarly journals Integrated component-support topology optimization for additive manufacturing with post-machining

2019 ◽  
Vol 25 (2) ◽  
pp. 255-265 ◽  
Author(s):  
Matthijs Langelaar
Keyword(s):  
Topology Optimization ◽  
Additive Manufacturing ◽  
High Performance ◽  
Process Model ◽  
Process Models ◽  
Content Type ◽  
Wide Range ◽  
Support Layout ◽  
Overhang Angle ◽  
Subtractive Machining

PurposeThe purpose of this paper is to communicate a method to perform simultaneous topology optimization of component and support structures considering typical metal additive manufacturing (AM) restrictions and post-print machining requirements.Design/methodology/approachAn integrated topology optimization is proposed using two density fields: one describing the design and another defining the support layout. Using a simplified AM process model, critical overhang angle restrictions are imposed on the design. Through additional load cases and constraints, sufficient stiffness against subtractive machining loads is enforced. In addition, a way to handle non-design regions in an AM setting is introduced.FindingsThe proposed approach is found to be effective in producing printable optimized geometries with adequate stiffness against machining loads. It is shown that post-machining requirements can affect optimal support structure layout.Research limitations/implicationsThis study uses a simplified AM process model based on geometrical characteristics. A challenge remains to integrate more detailed physical AM process models to have direct control of stress, distortion and overheating.Practical implicationsThe presented method can accelerate and enhance the design of high performance parts for AM. The consideration of post-print aspects is expected to reduce the need for design adjustments after optimization.Originality/valueThe developed method is the first to combine AM printability and machining loads in a single topology optimization process. The formulation is general and can be applied to a wide range of performance and manufacturability requirements.

PHENOMENA IN RESONANT TUNNELING THROUGH DEGENERATED ENERGY STATES WITH ELECTRON CORRELATION

2007 ◽  
Vol 21 (11) ◽  
pp. 1827-1835 ◽  
Author(s):  
VLADIMIR N. ERMAKOV ◽  
SERGEI P. KRUCHININ ◽  
HIDENOBU HORI ◽  
AKIHIKO FUJIWARA
Keyword(s):  
Electron Correlation ◽  
Resonant Tunneling ◽  
High Performance ◽  
Coulomb Repulsion ◽  
Analysis Method ◽  
Phonon Interaction ◽  
Strong Electron ◽  
Electron Phonon Interaction ◽  
Wide Range ◽  
Good Agreement

We introduce a general analysis method, which allows us to simulate the operation of high-performance molecular nano-devices and to design the expected function of a wide range of devices in nano-scale size. The method is based on the use of a resonant tunneling phenomenon, admitting strong electron correlation in a quantum dot with degenerated states. Three examples of the application of this method are given: Coulomb repulsion, uncorrelated resonant tunneling, and electron-phonon interaction. It is shown that there is a good agreement with experimental data in all three cases.

scholarly journals Measuring organizational climate via psychological networks analysis

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Igor Menezes ◽  
Ana Cristina Menezes ◽  
Elton Moraes ◽  
Pedro P. Pires
Keyword(s):  
Organizational Climate ◽  
Measurement Invariance ◽  
Graphical Model ◽  
Content Type ◽  
Organizational Policies ◽  
New Associations ◽  
Wide Range ◽  
Different Dimensions ◽  
The Individual ◽  
Thriving At Work

PurposeThis study investigates organizational climate under the thriving at work perspective using a network approach. The authors demonstrate how organizational climate functions as a complex system and what relationships between variables from different dimensions are the most important to characterize the construct.Design/methodology/approachBy surveying 119,266 workers from 284 companies based in Brazil, the authors estimated a Gaussian graphical model with LASSO regularization for the complete dataset and for two subsets of cases randomly drawn from the whole dataset. The walktrap algorithm was applied for community detection, and a strong model for measurement invariance was fit to test whether the organizational climate is perceived similarly across groups.FindingsResults show that the networks estimated for both groups are quite consistent, with similar number of communities and items detected. The same pattern was found for the expected influence of each item. Measurement invariance was confirmed, showing that organizational climate is perceived similarly in both groups. The most important community detected and whose items have higher levels of centrality was organizational commitment, followed by a community centered around macro-organizational aspects covering cultural integrity, organizational agility and responsible leadership.Research limitations/implicationsStudies in the field have attested to the possibility of investigating the phenomenon from four (Campbell et al., 1970) to over 80 dimensions (Koys and DeCottis, 1991). As a result, since several dimensions have been produced to investigate organizational climate, there is no consensus on the quality and number of dimensions that should be considered to measure such a vast and multifaceted construct. Built on thriving at work perspective, eight dimensions were devised to cover a wide range of characteristics that distinguish organizational climate, including those related to Industry 4.0 (Coetzee, 2019). However, one may argue that a few dimensions, namely social responsibility, diversity and inclusion, or even more items describing work-life balance could expand the depth and breadth of the instrument and potentially trigger new associations that might eventually impose a new logic to the comprehension of climate as a system. Future studies combining the dimensions investigated in this study with other dimensions are therefore highly recommended for an even more comprehensive investigation.Practical implicationsThe results of this investigation show how to apply psychological networks to gain insights into different variables and dimensions of organizational climate. These findings can be used for the development of organizational policies focused on the most relevant aspects of organizational climate. This information would allow organizations to go beyond simply describing the individual frequencies for each item and could even be used to create a weighted scoring model that could prioritize variables with higher levels of centrality.Originality/valueTo the authors’ knowledge, this is the first study that investigates organizational climate using psychological networks; it provides a better understanding of the relationships established between items from different dimensions as opposed to the common cause framework whose focus is on the investigation of dimensions separately.

scholarly journals High Sensitivity Optical Sensing Based on Modal Interferences in One-Dimensional Photonic Crystals

Proceedings ◽  
2018 ◽  
Vol 4 (1) ◽  
pp. 20
Author(s):  
Luis Torrijos-Morán ◽  
Jaime García-Rupérez
Keyword(s):  
High Performance ◽  
Slow Light ◽  
Single Channel ◽  
Optical Sensing ◽  
High Sensitivity ◽  
Edge Region ◽  
One Dimensional ◽  
Wide Range ◽  
Integrated Optical ◽  
Integrated Optical Sensor

A one-dimensional photonic crystal supporting two modes is presented as an interferometric integrated optical sensor. The sensing is carried out by obtaining the phase difference between both modes propagated through the same nanometric structure and how it changes when a refractive index (RI) variation over the sensor takes place. Due to the slow-light phenomenon, high sensitivities values are reached near the photonic bandgap edge region. As a result, a high performance, compact, and single-channel optical sensing approach is theoretically calculated and demonstrated with a wide range of applications in the biosensing field.

scholarly journals Pharmacodynamics of Ceftolozane plus Tazobactam Studied in anIn VitroPharmacokinetic Model of Infection

2015 ◽  
Vol 60 (1) ◽  
pp. 515-521 ◽  
Author(s):  
Alasdair P. MacGowan ◽  
Alan R. Noel ◽  
Sharon G. Tomaselli ◽  
Donna Nicholls ◽  
Karen E. Bowker
Keyword(s):  
High Performance ◽  
Human Pharmacokinetics ◽  
Content Type ◽  
Initial Inoculum ◽  
E Coli ◽  
Wide Range ◽  
Static Effect ◽  
Dose Ranging ◽  
Lactamase Inhibitor

ABSTRACTCeftolozane plus tazobactam is an antipseudomonal cephalosporin combined with tazobactam, an established beta-lactamase inhibitor, and hasin vitropotency against a range of clinically important β-lactamase-producing bacteria, including most extended-spectrum-β-lactamase (ESBL)-positiveEnterobacteriaceae. The pharmacodynamics of β-lactam–β-lactamase inhibitor combinations presents a number of theoretical and practical challenges, including modeling different half-lives of the compounds. In this study, we studied the pharmacodynamics of ceftolozane plus tazobactam againstEscherichia coliandPseudomonas aeruginosausing anin vitropharmacokinetic model of infection. Five strains ofE. coli, including three clinical strains plus two CTX-M-15 (one high and one moderate) producers, and five strains ofP. aeruginosa, including two with OprD overexpression and AmpC β-lactamases, were employed. Ceftolozane MICs (E. coli, 0.12 to 0.25 mg/liter, andP. aeruginosa, 0.38 to 8 mg/liter) were determined in the presence of 4 mg/liter tazobactam. Dose ranging of ceftolozane (percentage of time in which the free-drug concentration exceeds the MIC [fT>MIC], 0 to 100%) plus tazobactam (human pharmacokinetics) was simulated every 8 hours, with half-lives (t1/2) of 2.5 and 1 h, respectively. Ceftolozane and tazobactam concentrations were confirmed by high-performance liquid chromatography (HPLC). The ceftolozane-plus-tazobactamfT>MIC values at 24 h for a static effect and a 1-log and 2-log drop in initial inoculum forE. coliwere 27.8% ± 5.6%, 33.0% ± 5.6%, and 39.6% ± 8.5%, respectively. CTX-M-15 production did not affect the 24-hfT>MIC forE. colistrains. The ceftolozane-plus-tazobactamfT>MIC values for a 24-h static effect and a 1-log and 2-log drop forP. aeruginosawere 24.9% ± 3.0%, 26.6% ± 3.9%, and 31.2% ± 3.6%. Despite a wide range of absolute MICs, the killing remained predictable as long as the MICs were normalized to the correspondingfT>MIC. Emergence of resistance on 4× MIC plates and 8× MIC plates occurred maximally at anfT>MIC of 10 to 30% and increased as time of exposure increased. ThefT>MIC for a static effect for ceftolozane plus tazobactam is less than that observed with other cephalosporins againstE. coliandP. aeruginosaand is more similar to thefT>MIC reported for carbapenems.

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