On the Dynamics of Two Mutually-Coupled, Electromagnetically-Actuated Microbeam Oscillators

2011 ◽  
Author(s):  
Andrew B. Sabater ◽  
Jeffrey F. Rhoads
Keyword(s):  
Signal Processing ◽  
Coupled Oscillators ◽  
Practical Applications ◽  
Modeling Analysis ◽  
Predictive Design ◽  
Oscillator Arrays ◽  
And Control ◽  
Electromagnetically Actuated ◽  
Nonlinear Behaviors

This work describes the modeling, analysis, predictive design, and control of self-excited oscillators, and associated arrays, founded upon electromagnetically-actuated microbeams. The study specifically focuses on the characterization of nonlinear behaviors arising in isolated oscillators and small arrays of nearly-identical, mutually-coupled oscillators. The work provides a framework for the exploration of larger oscillator arrays with different forms of coupling and feedback, which can be exploited in practical applications ranging from signal processing to micromechanical neurocomputing.

On the Dynamics of Two Mutually-Coupled, Electromagnetically-Actuated Microbeam Oscillators

2012 ◽  
Vol 7 (3) ◽  
Author(s):  
Andrew B. Sabater ◽  
Jeffrey F. Rhoads
Keyword(s):  
Signal Processing ◽  
Coupled Oscillators ◽  
Practical Applications ◽  
Modeling Analysis ◽  
Predictive Design ◽  
Oscillator Arrays ◽  
And Control ◽  
Electromagnetically Actuated ◽  
Nonlinear Behaviors

This work describes the modeling, analysis, predictive design, and control of self-excited oscillators, and associated arrays, founded upon electromagnetically-actuated microbeams. The study specifically focuses on the characterization of nonlinear behaviors arising in isolated oscillators and small arrays of nearly-identical, mutually-coupled oscillators. The work provides a framework for the exploration of larger oscillator arrays with different forms of coupling and feedback, which can be exploited in practical applications ranging from signal processing to micromechanical neurocomputing.

On the Nonlinear Dynamics of Electromagnetically-Transduced Microresonators

2012 ◽  
Author(s):  
Andrew B. Sabater ◽  
Vijay Kumar ◽  
Aamer Mahmood ◽  
Jeffrey F. Rhoads
Keyword(s):  
Nonlinear Response ◽  
Experimental Characterization ◽  
Complete Understanding ◽  
Mass Sensing ◽  
Permanent Magnetic Field ◽  
Input And Output ◽  
Modeling Analysis ◽  
Electromagnetically Actuated ◽  
A Current

This work investigates the dynamics of electromagnetically-actuated and sensed microresonators. These resonators consist of a silicon microcantilever and a current-carrying metallic wire loop. When placed in a permanent magnetic field, the devices vibrate due to Lorentz interactions. These vibrations, in turn, induce an electromotive force, which can be correlated to the dynamic response of the device. The nature of this transduction process results in an intrinsic coupling between the system’s input and output, which must be analytically and experimentally characterized to fully understand the dynamics of the devices of interest. This paper seeks to address this need through the modeling, analysis, and experimental characterization of the nonlinear response of electromagnetically-transduced microcantilevers in the presence of inductive and resistive coupling between the devices’ input and output ports. A complete understanding of this behavior should enable the application of electromagnetically-transduced microsystems in practical contexts ranging from resonant mass sensing to micromechanical signal processing.

Characterization of intergranular cuprous oxide in polycrystalline YBa2Cu3O7-x

1988 ◽  
Vol 46 ◽  
pp. 880-881
Author(s):  
Bradley L. Thiel ◽  
Chan Han R. P. ◽  
Kurosky L. C. Hutter ◽  
I. A. Aksay ◽  
Mehmet Sarikaya
Keyword(s):  
Grain Boundary ◽  
Cuprous Oxide ◽  
Room Temperature ◽  
Boundary Phase ◽  
Spectroscopic Techniques ◽  
Transition Width ◽  
Practical Applications ◽  
Thin Foils ◽  
Superconducting Oxides

The identification of extraneous phases is important in understanding of high Tc superconducting oxides. The spectroscopic techniques commonly used in determining the origin of superconductivity (such as RAMAN, XPS, AES, and EXAFS) are surface-sensitive. Hence a grain boundary phase several nanometers thick could produce irrelevant spectroscopic results and cause erroneous conclusions. The intergranular phases present a major technological consideration for practical applications. In this communication we report the identification of a Cu2O grain boundary phase which forms during the sintering of YBa2Cu3O7-x (1:2:3 compound).Samples are prepared using a mixture of Y2O3. CuO, and BaO2 powders dispersed in ethanol for complete mixing. The pellets pressed at 20,000 psi are heated to 950°C at a rate of 5°C per min, held for 1 hr, and cooled at 1°C per min to room temperature. The samples show a Tc of 91K with a transition width of 2K. In order to prevent damage, a low temperature stage is used in milling to prepare thin foils which are then observed, using a liquid nitrogen holder, in a Philips 430T at 300 kV.

Processing and characterization of YBa2Cu3O7−x/Ag composites

1990 ◽  
Vol 48 (4) ◽  
pp. 46-47
Author(s):  
Jafar Javadpour ◽  
Bradley L. Thiel ◽  
Sarikaya Mehmet ◽  
Ilhan A. Aksay
Keyword(s):  
Composite System ◽  
Precursor Solution ◽  
Microstructural Development ◽  
Superconducting Properties ◽  
Practical Applications ◽  
Nitrate Precursor ◽  
Cold Pressed ◽  
Tape Cast ◽  
Composite Samples

Practical applications of bulk YBa2Cu3O7−x materials have been limited because of their inadequate critical current density (jc) and poor mechanical properties. Several recent reports have indicated that the addition of Ag to the YBa2Cu3O7−x system is beneficial in improving both mechanical and superconducting properties. However, detailed studies concerning the effect of Ag on the microstructural development of the cermet system have been lacking. Here, we present some observations on the microstructural evolution in the YBa2Cu3O7−x/Ag composite system.The composite samples were prepared by mixing various amounts (2.5 - 50 wt%) AgNO3 in the YBa2Cu3O7−x nitrate precursor solution. These solutions were then spray dried and the resulting powders were either cold pressed or tape cast. The microstructures of the sintered samples were analyzed using SEM (Philips 515) and an analytical TEM (Philips 430T).The SEM micrographs of the compacts with 2.5 and 50 wt% Ag addition sintered at 915°C (below the melting point of Ag) for 1 h in air are displayed in Figs. 1 and 2, respectively.

Introduction

2018 ◽  
Author(s):  
Elizabeth S. Radcliffe
Keyword(s):  
Early Modern ◽  
Historical Background ◽  
Consistent Picture ◽  
And Control ◽  
Good And Evil

The Introduction offers, first, a brief historical background to Hume’s theory of the passions, which is further elaborated in the APPENDIX. Foremost among the theses of the early modern rationalists—like Reynolds, Senault, Descartes, Cudworth, and Clarke—to which Hume is responding are: that many passions left unregulated lead to the pursuit of unsuitable objects, that reason can overcome the pernicious influence of the passions and control our actions, and that the passions are states that represent good and evil. Second, the Introduction presents a sketch of Hume’s characterization of reason and passion and his account of their relationship. Third, it explains the method of interpretation used in this book and previews its chapters. The approach is coherentist: to present an intelligible and consistent picture of Hume’s theory of passion and action, accounting for as many of the relevant texts as possible.

scholarly journals Design, Construction, and Control for an Underwater Vehicle Type Sepiida

Robotica ◽  
2020 ◽  
pp. 1-18
Author(s):  
M. Garcia ◽  
P. Castillo ◽  
E. Campos ◽  
R. Lozano
Keyword(s):  
Embedded System ◽  
Closed Loop ◽  
Underwater Vehicle ◽  
Mathematical Representation ◽  
Closed Loop System ◽  
Vehicle Type ◽  
Mathematical Equations ◽  
And Control ◽  
Design Construction

SUMMARY A novel underwater vehicle configuration with an operating principle as the Sepiida animal is presented and developed in this paper. The mathematical equations describing the movements of the vehicle are obtained using the Newton–Euler approach. An analysis of the dynamic model is done for control purposes. A prototype and its embedded system are developed for validating analytically and experimentally the proposed mathematical representation. A real-time characterization of one mass is done to relate the pitch angle with the radio of displacement of the mass. In addition, first validation of the closed-loop system is done using a linear controller.

scholarly journals Clinical characterization of dysautonomia in long COVID-19 patients

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nicolas Barizien ◽  
Morgan Le Guen ◽  
Stéphanie Russel ◽  
Pauline Touche ◽  
Florent Huang ◽  
...  
Keyword(s):  
Mixed Models ◽  
Repeated Measures ◽  
Physical Medicine ◽  
Persistent Symptoms ◽  
Index Changes ◽  
Changes Over Time ◽  
And Control ◽  
Testing Group ◽  
Over Time

AbstractIncreasing numbers of COVID-19 patients, continue to experience symptoms months after recovering from mild cases of COVID-19. Amongst these symptoms, several are related to neurological manifestations, including fatigue, anosmia, hypogeusia, headaches and hypoxia. However, the involvement of the autonomic nervous system, expressed by a dysautonomia, which can aggregate all these neurological symptoms has not been prominently reported. Here, we hypothesize that dysautonomia, could occur in secondary COVID-19 infection, also referred to as “long COVID” infection. 39 participants were included from December 2020 to January 2021 for assessment by the Department of physical medicine to enhance their physical capabilities: 12 participants with COVID-19 diagnosis and fatigue, 15 participants with COVID-19 diagnosis without fatigue and 12 control participants without COVID-19 diagnosis and without fatigue. Heart rate variability (HRV) during a change in position is commonly measured to diagnose autonomic dysregulation. In this cohort, to reflect HRV, parasympathetic/sympathetic balance was estimated using the NOL index, a multiparameter artificial intelligence-driven index calculated from extracted physiological signals by the PMD-200 pain monitoring system. Repeated-measures mixed-models testing group effect were performed to analyze NOL index changes over time between groups. A significant NOL index dissociation over time between long COVID-19 participants with fatigue and control participants was observed (p = 0.046). A trend towards significant NOL index dissociation over time was observed between long COVID-19 participants without fatigue and control participants (p = 0.109). No difference over time was observed between the two groups of long COVID-19 participants (p = 0.904). Long COVID-19 participants with fatigue may exhibit a dysautonomia characterized by dysregulation of the HRV, that is reflected by the NOL index measurements, compared to control participants. Dysautonomia may explain the persistent symptoms observed in long COVID-19 patients, such as fatigue and hypoxia. Trial registration: The study was approved by the Foch IRB: IRB00012437 (Approval Number: 20-12-02) on December 16, 2020.

scholarly journals The Combined Effect of Weaning Stress and Immune Activation during Pig Gestation on Serum Cytokine and Analyte Concentrations

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2274
Author(s):  
Haley E. Rymut ◽  
Laurie A. Rund ◽  
Courtni R. Bolt ◽  
Maria B. Villamil ◽  
Bruce R. Southey ◽  
...  
Keyword(s):  
Immune Activation ◽  
Management Practices ◽  
Interleukin 1 ◽  
Interleukin 2 ◽  
Blood Chemistry ◽  
Respiratory Syndrome Virus ◽  
Weaning Stress ◽  
And Control ◽  
Metabolic Hormone

Weaning stress can elicit changes in the metabolic, hormone and immune systems of pigs and interact with prolonged disruptions stemming from maternal immune activation (MIA) during gestation. The present study advances the characterization of the combined effects of weaning stress and MIA on blood chemistry, immune and hormone indicators that inform on the health of pigs. Three-week-old female and male offspring of control gilts or gilts infected with the porcine reproductive and respiratory syndrome virus were allocated to weaned or nursed groups. The anion gap and bilirubin profiles suggest that MIA enhances tolerance to the effects of weaning stress. Interleukin 1 beta and interleukin 2 were highest among weaned MIA females, and cortisol was higher among weaned relative to nursed pigs across sexes. Canonical discriminant analysis demonstrated that weaned and nursed pigs have distinct chemistry profiles, whereas MIA and control pigs have distinct cytokine profiles. The results from this study can guide management practices that recognize the effects of the interaction between MIA and weaning stress on the performance and health of pigs.

scholarly journals Genotypic Characterization of Antimicrobial Resistant Salmonella spp. Strains from Three Poultry Processing Plants in Colombia

Foods ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 491
Author(s):  
Alejandra Ramirez-Hernandez ◽  
Ana K. Carrascal-Camacho ◽  
Andrea Varón-García ◽  
Mindy M. Brashears ◽  
Marcos X. Sanchez-Plata
Keyword(s):  
Antimicrobial Resistance ◽  
Salmonella Spp ◽  
Microbial Profile ◽  
Antimicrobial Resistance Genes ◽  
Processing Plants ◽  
Poultry Processing ◽  
Paratyphi B ◽  
And Control ◽  
Sequence Types

The poultry industry in Colombia has implemented several changes and measures in chicken processing to improve sanitary operations and control pathogens’ prevalence. However, there is no official in-plant microbial profile reference data currently available throughout the processing value chains. Hence, this research aimed to study the microbial profiles and the antimicrobial resistance of Salmonella isolates in three plants. In total, 300 samples were collected in seven processing sites. Prevalence of Salmonella spp. and levels of Enterobacteriaceae were assessed. Additionally, whole-genome sequencing was conducted to characterize the isolated strains genotypically. Overall, the prevalence of Salmonella spp. in each establishment was 77%, 58% and 80% for plant A, B, and C. The mean levels of Enterobacteriaceae in the chicken rinsates were 5.03, 5.74, and 6.41 log CFU/mL for plant A, B, and C. Significant reductions were identified in the counts of post-chilling rinsate samples; however, increased levels were found in chicken parts. There were six distinct Salmonella spp. clusters with the predominant sequence types ST32 and ST28. The serotypes Infantis (54%) and Paratyphi B (25%) were the most commonly identified within the processing plants with a high abundance of antimicrobial resistance genes.

Sign in / Sign up

Export Citation Format

Share Document