Analysis of Plastic Deformation in Metal-Ceramic Nanolayers During Cyclic Indentation

2012 ◽  
Author(s):  
C. B. Blada ◽  
Y.-L. Shen
Keyword(s):  
Plastic Deformation ◽  
Transient Behavior ◽  
Primary Objective ◽  
Cyclic Plasticity ◽  
Rate Dependent ◽  
Diamond Indenter ◽  
Metal Ceramic ◽  
Elastic Loading ◽  
Cyclic Indentation ◽  
And Control

The indentation behavior of metal/ceramic nanolayers is studied, with attention devoted to cyclic response under fixed maximum and minimum indentation loads. The primary objective is to examine the evolving plastic deformation in the ductile metal constrained by the hard ceramic layers. The model consists of alternating aluminum (Al) and silicon carbide (SiC) thin films on a silicon substrate, with the Al/SiC layered structure being indented by a diamond indenter. The rate-dependent viscoplastic response of Al is taken into account in the numerical model. It is shown that plastic deformation in the ductile Al layers continues to occur during the unloading phase of the first cycle, as well as during subsequent reload/unload processes. The cyclic plasticity results in an open load-displacement loop, and the indenter continues to move deeper with each cycle. For the control model of a homogeneous Al film, there is no hysteresis loop and the transient behavior soon approaches stabilization, showing repetitive elastic loading/unloading. The modeling results are also compared with cyclic nanoindentation experiments conducted on the same metal-ceramic multilayer system and control specimen.

scholarly journals A Conceptual Model of Measurement Uncertainty in IoT Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1827
Author(s):  
Piotr Cofta ◽  
Kostas Karatzas ◽  
Cezary Orłowski
Keyword(s):  
Sensor Networks ◽  
Internet Of Things ◽  
Reference Model ◽  
Primary Objective ◽  
Theory And Practice ◽  
Fitness For Purpose ◽  
Industrial Practice ◽  
Control Networks ◽  
And Control ◽  
Measurement And Control

The growing popularity of inexpensive IoT (Internet of Things) sensor networks makes their uncertainty an important aspect of their adoption. The uncertainty determines their fitness for purpose, their perceived quality and the usefulness of information they provide. Nevertheless, neither the theory nor the industrial practice of uncertainty offer a coherent answer on how to address uncertainty of networks of this type and their components. The primary objective of this paper is to facilitate the discussion of what progress should be made regarding the theory and the practice of uncertainty of IoT sensor networks to satisfy current needs. This paper provides a structured overview of uncertainty, specifically focusing on IoT sensor networks. It positions IoT sensor networks as contrasted with professional measurement and control networks and presents their conceptual sociotechnical reference model. The reference model advises on the taxonomy of uncertainty proposed in this paper that demonstrates semantic differences between various views on uncertainty. This model also allows for identifying key challenges that should be addressed to improve the theory and practice of uncertainty in IoT sensor networks.

Abstract 2769: Bradycardia-Dependent Augmentation of J-wave Elevation in Patients with Idiopathic Ventricular Fibrillation

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Koichi Mizumaki ◽  
Akira Fujiki ◽  
Masao Sakabe ◽  
Tamotsu Sakamoto ◽  
Yosuke Nakatani ◽  
...  
Keyword(s):  
Ventricular Fibrillation ◽  
Linear Regression ◽  
Wave Amplitude ◽  
Idiopathic Ventricular Fibrillation ◽  
Cardioverter Defibrillator ◽  
Rate Dependent ◽  
Wave Elevation ◽  
Male Patients ◽  
And Control ◽  
J Wave

Although J-wave elevation (JWE) in the inferior or lateral leads is characteristic of subtype of idiopathic ventricular fibrillation (IVF), difference between malignant and benign JWE remains to be elucidated. So, we assessed the hypothesis that the rate dependent changes in JWE could be different between patients with IVF and control subjects. Six male patients with IVF and 18 age matched male controls with JWE (>2 mm) in the lateral leads were studied. CM-5 lead digital Holter ECG was recorded and J wave amplitude was automatically measured. J/RR relationships were evaluated by means of J/RR linear regression lines for 24 hours, and according to four 6-hour periods. From J-RR linear regression lines, J-RR slope (mm/sec), J wave amplitude (mm) at RR intervals of both 0.6 sec and 1.2 sec (J (0.6) and J (1.2) ) were determined. In all 6 patients with IVF, the time of spontaneous episodes of VF were investigated from the implantable cardioverter defibrillator (ICD) stored data. For 24 hours, J-RR slope was greater in IVF patients than in controls (3.5±0.7 vs 2.4±0.8, p<0.01). (J (0.6) ) wasn’t different between 2 groups; however, J (1.2) was greater in IVF patients than in controls (2.8±0.9 vs 2.0±0.6, p<0.05). In IVF patients, ST/RR slope was highest during 18:00–24:00; however, these circadian changes were blunted in controls. J(1.2) was greater during 18:00 – 6:00 in IVF patients than in controls. Seven (59%) of total 9 episodes of spontaneous VF of IVF patients occurred during 18:00 – 6:00. In patients with subtype of IVF, JWE augmented during bradycardia especially at night. This could relate to nighttime occurrence of IVF.

Rate-dependent shortening of action potential duration increases ventricular vulnerability in failing rabbit heart

2011 ◽  
Vol 300 (2) ◽  
pp. H565-H573 ◽  
Author(s):  
Masahide Harada ◽  
Yukiomi Tsuji ◽  
Yuko S. Ishiguro ◽  
Hiroki Takanari ◽  
Yusuke Okuno ◽  
...  
Keyword(s):  
Action Potential ◽  
High Frequency ◽  
Rabbit Heart ◽  
Left Ventricular ◽  
High Frequency Stimulation ◽  
Electrophysiological Properties ◽  
Rate Dependent ◽  
Frequency Stimulation ◽  
And Control

Congestive heart failure (CHF) predisposes to ventricular fibrillation (VF) in association with electrical remodeling of the ventricle. However, much remains unknown about the rate-dependent electrophysiological properties in a failing heart. Action potential properties in the left ventricular subepicardial muscles during dynamic pacing were examined with optical mapping in pacing-induced CHF ( n = 18) and control ( n = 17) rabbit hearts perfused in vitro. Action potential durations (APDs) in CHF were significantly longer than those observed for controls at basic cycle lengths (BCLs) >1,000 ms but significantly shorter at BCLs <400 ms. Spatial APD dispersions were significantly increased in CHF versus control (by 17–81%), and conduction velocity was significantly decreased in CHF (by 6–20%). In both groups, high-frequency stimulation (BCLs <150 ms) always caused spatial APD alternans; spatially concordant alternans and spatially discordant alternans (SDA) were induced at 60% and 40% in control, respectively, whereas 18% and 82% in CHF. SDA in CHF caused wavebreaks followed by reentrant excitations, giving rise to VF. Incidence of ventricular tachycardia/VFs elicited by high-frequency dynamic pacing (BCLs <150 ms) was significantly higher in CHF versus control (93% vs. 20%). In CHF, left ventricular subepicardial muscles show significant APD shortenings at short BCLs favoring reentry formations following wavebreaks in association with SDA. High-frequency excitation itself may increase the vulnerability to VF in CHF.

Cyclic indentation behavior of metal–ceramic nanolayered composites

2012 ◽  
Vol 557 ◽  
pp. 119-125 ◽  
Author(s):  
Y.-L. Shen ◽  
C.B. Blada ◽  
J.J. Williams ◽  
N. Chawla
Keyword(s):  
Metal Ceramic ◽  
Cyclic Indentation

Plastic Deformation of Metal/Ceramic Nanolayered Composites

JOM ◽  
2014 ◽  
Vol 66 (10) ◽  
pp. 2078-2085 ◽  
Author(s):  
I. Salehinia ◽  
S. Shao ◽  
J. Wang ◽  
H. M. Zbib
Keyword(s):  
Plastic Deformation ◽  
Metal Ceramic

scholarly journals Testing a passive deterrent on longlines to reduce sperm whale depredation in the Gulf of Alaska

2015 ◽  
Vol 72 (5) ◽  
pp. 1667-1672 ◽  
Author(s):  
Victoria O'Connell ◽  
Janice Straley ◽  
Joe Liddle ◽  
Lauren Wild ◽  
Linda Behnken ◽  
...  
Keyword(s):  
Sperm Whale ◽  
Gulf Of Alaska ◽  
Primary Objective ◽  
Collaborative Effort ◽  
Physeter Macrocephalus ◽  
Anoplopoma Fimbria ◽  
Acoustic Data ◽  
The Individual ◽  
And Control ◽  
Individual Fishing Quota

Abstract In Alaska, sperm whale (Physeter macrocephalus) depredation on longline sets has increased since implementation of the Individual Fishing Quota programme in 1995. A collaborative effort (SEASWAP) between longliners, scientists, and managers has undertaken research to evaluate this depredation with a primary objective to develop and test a passive deterrent that would reduce depredation without reducing catch rate of sablefish (Anoplopoma fimbria). Commercial longliners, fishing for their own sablefish quotas during the regular season, deployed beaded gear (25 mm lucite beads attached to gangions) with control gear and set recorders to collect acoustic data. Beaded and control gear were randomly assigned by skate quad (672 hooks) with 5 quads in each longline set. Acoustic recorders were used to document sperm whale creak–pause events, representative of depredation of the longline gear. Although there were more sablefish per skate quad on the beaded gear and there was a decrease in depredation events on the beaded gear compared with the control, neither effect was significant (p = 0.205 and 0.364, respectively). The SEASWAP project is testing other deterrent strategies including gear modifications and the establishment of a sighting network to improve avoidance.

Sign in / Sign up

Export Citation Format

Share Document