Measurement of the response time of magnetorheological fluids and ferrofluids based on the magnetic susceptibility response

2021 ◽  
pp. 1045389X2110386
Author(s):  
Barnabás Horváth ◽  
Péter Decsi ◽  
István Szalai
Keyword(s):  
Magnetic Susceptibility ◽  
Response Time ◽  
Characteristic Time ◽  
Response Times ◽  
Magnetorheological Fluids ◽  
Point Of View ◽  
Resonant Circuit ◽  
Dynamic Susceptibility ◽  
Scale Response ◽  
The Time Domain

From a technological point of view one of the most important characteristics of magnetorheological fluids and ferrofluids is their fast (on the [Formula: see text] s time scale) response to external magnetic fields. We report response time measurements based on the time domain magnetic susceptibility response of commercially available fluids. The dynamic susceptibility is measured over time in the presence of external magnetic field by a method using an inductive resonant circuit. The response time of the fluids is extracted as the characteristic time constant from the response to ramp excitation. We investigated the influence of the slope of the ramp excitation on the response time. The macroscopic response times were correlated with the characteristic time scales of the microscopic processes behind the susceptibility response. In case of the magnetorheological fluids the overall response time have been associated with the characteristic times of structure formation. The relatively slow response of the ferrofluid corresponded to a relaxation dominated by Brownian mechanism, which indicated the presence of multi-core clusters.

scholarly journals Stimulus-response time to invasive blood pressure alarms: implications for the safety of critical-care patients

2014 ◽  
Vol 35 (2) ◽  
pp. 135-141 ◽  
Author(s):  
Adele Kuckartz Pergher ◽  
Roberto Carlos Lyra da Silva
Keyword(s):  
Blood Pressure ◽  
Response Time ◽  
Response Times ◽  
Hemodynamic Instability ◽  
Military Hospital ◽  
Invasive Blood Pressure ◽  
Stimulus Response ◽  
The City ◽  
Physical Layout

Observational, descriptive, exploratory, case study with the objective of measuring the stimulus-response time of the team to alarms monitoring invasive blood pressure (IBP) and analyzing the implications of this time for the safety of the patient. From January to March 2013, 60 hours of structured observation were conducted with registration of the alarms activated by IBP monitors in an adult ICU at a military hospital in the city of Rio de Janeiro. 76 IBP alarms were recorded (1.26 alarms/hour), 21 of which (28%) were attended to and 55 (72%) considered as fatigued. The average response time to the alarms was 2 min. 45 sec. The deficit in human resource and physical layout were factors determining the delay in response to the alarms. The increase in response times to these alarms may compromise the safety of patients with hemodynamic instability, especially in situations such as shock and the use of vasoactive drugs.

scholarly journals English Speakers’ Implicit Gender Concepts Influence Their Processing of French Grammatical Gender: Evidence for Semantically Mediated Cross-Linguistic Influence

2021 ◽  
Vol 12 ◽  
Author(s):  
Elena Nicoladis ◽  
Chris Westbury ◽  
Cassandra Foursha-Stevenson
Keyword(s):  
Second Language ◽  
Response Time ◽  
Response Times ◽  
First Language ◽  
Grammatical Gender ◽  
Word Embedding ◽  
English Speakers ◽  
French Words ◽  
L1 English ◽  
French Gender

Second language (L2) learners often show influence from their first language (L1) in all domains of language. This cross-linguistic influence could, in some cases, be mediated by semantics. The purpose of the present study was to test whether implicit English gender connotations affect L1 English speakers’ judgments of the L2 French gender of objects. We hypothesized that gender estimates derived from word embedding models that measure similarity of word contexts in English would affect accuracy and response time on grammatical gender (GG) decision in L2 French. L2 French learners were asked to identify the GG of French words estimated to be either congruent or incongruent with the implicit gender in English. The results showed that they were more accurate with words that were congruent with English gender connotations than words that were incongruent, suggesting that English gender connotations can influence grammatical judgments in French. Response times showed the same pattern. The results are consistent with semantics-mediated cross-linguistic influence.

scholarly journals Discrete-time inverse optimal control for a reaction wheel pendulum: a passivity-based control approach

2020 ◽  
Vol 19 (4) ◽  
pp. 123-132 ◽  
Author(s):  
Oscar Danilo Montoya ◽  
Walter Gil-González ◽  
Federico Martin Serra
Keyword(s):  
Optimal Control ◽  
Discrete Time ◽  
Point Of View ◽  
Control Analysis ◽  
Inverse Optimal Control ◽  
Reaction Wheel ◽  
Control Approach ◽  
Control Functions ◽  
Passivity Based Control ◽  
The Time Domain

In this paper it is presented the design of a controller for a reaction wheel pendulum using a discrete-time representation via optimal control from the point of view of passivity-based control analysis. The main advantage of the proposed approach is that it allows to guarantee asymptotic stability convergence using a quadratic candidate Lyapunovfunction. Numerical simulations show that the proposed inverse optimal control design permits to reach superiornumerical performance reported by continuous approaches such as Lyapunov control functions and interconnection,and damping assignment passivity-based controllers. An additional advantageof the proposed inverse optimal controlmethod is its easy implementation since it does not employ additional states. It is only required a basic discretizationof the time-domain dynamical model based on the backward representation. All the simulations are carried out inMATLAB/OCTAVE software using a codification on the script environment.

scholarly journals Glacier volume response time and its links to climate and topography based on a conceptual model of glacier hypsometry

2009 ◽  
Vol 3 (1) ◽  
pp. 243-275 ◽  
Author(s):  
S. C. B. Raper ◽  
R. J. Braithwaite
Keyword(s):  
Response Time ◽  
Mass Balance ◽  
Conceptual Model ◽  
Response Times ◽  
Climate Modelling ◽  
Scaling Relation ◽  
Ablation Volume ◽  
Glacier Terminus ◽  
Volume Response ◽  
Simple Ratio

Abstract. Glacier volume response time is a measure of the time taken for a glacier to adjust its geometry to a climate change. It is currently believed that the volume response time is given approximately by the ratio of glacier thickness to ablation at the glacier terminus. We propose a new conceptual model of glacier hypsometry (area-altitude relation) and derive the volume response time where climatic and topographic parameters are separated. The former is expressed by mass balance gradients which we derive from glacier-climate modelling and the latter are quantified with data from the World Glacier Inventory. Aside from the well-known scaling relation between glacier volume and area, we establish a new scaling relation between glacier altitude range and area, and evaluate it for seven regions. The presence of this scaling parameter in our response time formula accounts for the mass balance elevation feedback and leads to longer response times than given by the simple ratio of glacier thickness to ablation. Volume response times range from decades to thousands of years for glaciers in maritime (wet-warm) and continental (dry-cold) climates, respectively. The combined effect of volume-area and altitude-area scaling relations is such that volume response time can increase with glacier area (Axel Heiberg Island and Svalbard), hardly change (Northern Scandinavia, Southern Norway and the Alps) or even get smaller (The Caucasus and New Zealand).

scholarly journals A High-Stakes Approach to Response Time Effort in Low-Stakes Assessment

2021 ◽  
Vol 7 (4) ◽  
pp. 571-586
Author(s):  
Munevver Ilgun
Keyword(s):  
Response Time ◽  
Failure Time ◽  
Response Times ◽  
Survival Models ◽  
Accelerated Failure Time ◽  
Data Sets ◽  
High Stakes ◽  
Problem Solving Skills ◽  
Educational Stakeholders ◽  
Accelerated Failure Time Models

<p style="text-align: justify;">Response times are one of the important sources that provide information about the performance of individuals during a test process. The main purpose of this study is to show that survival models can be used in educational data. Accordingly, data sets of items measuring literacy, numeracy and problem-solving skills of the countries participating in Round 3 of the Programme for the International Assessment of Adult Competencies were used. Accelerated failure time models have been analyzed for each country and domain.  As a result of the analysis of the models in which various covariates are included as independent variables, and response time for giving correct answers is included as a dependent variable, it was found the associations between the covariates and response time for giving correct answers were concluded to vary from one domain to another or from one country to another. The results obtained from the present study have provided the educational stakeholders and practitioners with valuable information.</p>

scholarly journals Response Time Distribution Analysis of Semantic and Response Interference in a Manual Response Stroop Task

2019 ◽  
Vol 66 (3) ◽  
pp. 231-238 ◽  
Author(s):  
Nabil Hasshim ◽  
Michelle Downes ◽  
Sarah Bate ◽  
Benjamin A. Parris
Keyword(s):  
Response Time ◽  
Stroop Task ◽  
Time Distribution ◽  
Response Times ◽  
Response Time Distribution ◽  
Stroop Interference ◽  
Response Conflict ◽  
Distribution Analysis ◽  
Manual Response ◽  
Response Interference

Abstract. Previous analyses of response time distributions have shown that the Stroop effect is observed in the mode (μ) and standard deviation (σ) of the normal part of the distribution, as well as its tail (τ). Specifically, interference related to semantic and response processes has been suggested to specifically affect the mode and tail, respectively. However, only one study in the literature has directly manipulated semantic interference, and none manipulating response interference. The present research aims to address this gap by manipulating both semantic and response interference in a manual response Stroop task, and examining how these components of Stroop interference affect the response time distribution. Ex-Gaussian analysis showed both semantic and response conflict to only affect τ. Analyzing the distribution by rank-ordered response times (Vincentizing) showed converging results as the magnitude of both semantic and response conflict increased with slower response times. Additionally, response conflict appeared earlier on the distribution compared to semantic conflict. These findings further highlight the difficulty in attributing specific psychological processes to different parameters (i.e., μ, σ, and τ). The effect of different response modalities on the makeup of Stroop interference is also discussed.

Anisotropy of out-of-phase magnetic susceptibility due to eddy currents in graphite ore and its structural implications

2021 ◽  
Author(s):  
František Hrouda ◽  
Jan Franěk ◽  
Martin Chadima ◽  
Josef Ježek ◽  
Štěpánka Mrázová ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Eddy Currents ◽  
Regional Metamorphism ◽  
Ductile Deformation ◽  
Dynamic Susceptibility ◽  
Phase Component ◽  
Simultaneous Control ◽  
Order Of Magnitude ◽  
Moldanubian Unit ◽  
Sufficient Precision

&lt;p&gt;Magnetostatic susceptibility of single crystals of graphite is negative (the mineral is diamagnetic) and strongly anisotropic. The in-phase component of dynamic susceptibility (measured in alternating magnetic field) is also negative, but an order-of-magnitude stronger than the magnetostatic susceptibility. The out-of-phase component, which is no doubt due to electrical eddy currents, is positive and strong. Consequently, if the graphite crystals in graphite ore are oriented preferentially by crystal lattice (LPO), one would expect strong anisotropy of magnetic susceptibility (AMS) of graphite ore in both in-phase (ipAMS) and out-of-phase (opAMS) components. The ipAMS is controlled not only by the LPO of graphite, but also by the preferred orientation of paramagnetic and ferromagnetic minerals of the barren rock, while the opAMS indicates only the LPO of graphite. In graphite ores occurring in the Moldanubian Unit of Southern Bohemia, the in-phase susceptibility ranges from negative values in the order of 10&lt;sup&gt;-5&lt;/sup&gt; [SI units] to positive values in the order of 10&lt;sup&gt;-4&lt;/sup&gt;. This probably indicates simultaneous control by graphite and paramagnetic and/or ferromagnetic minerals. On the other hand, the out-of-phase susceptibility is much higher, in the order of 10&lt;sup&gt;-4&lt;/sup&gt;, and no doubt indicates its graphite control. The degree of ipAMS is moderate, that of opAMS is truly high. The ipAMS foliation is roughly parallel to the metamorphic foliation in ores and wall rocks and the ipAMS lineation is parallel to the mesoscopic lineation. The opAMS is inverse to the ipAMS with the opAMS lineation being perpendicular to the metamorphic foliation. All this indicates a conspicuous LPO of graphite in the ore that was probably created during Variscan regional metamorphism and associated ductile deformation. The opAMS has therefore shown an effective tool for the investigation of the LPO of graphite in graphite ore or graphite-bearing rocks provided that the opAMS is strong enough to be determined with sufficient precision and graphite is the only conductive mineral in the samples investigated.&lt;/p&gt;

scholarly journals Who can spot an online romance scam?

2019 ◽  
Vol 26 (2) ◽  
pp. 623-633 ◽  
Author(s):  
Monica T. Whitty
Keyword(s):  
Response Time ◽  
Design Methodology ◽  
Response Times ◽  
Belief Systems ◽  
Personality Inventory ◽  
Human Detection ◽  
Content Type ◽  
Consideration Of Future Consequences ◽  
Online Study ◽  
Future Consequences

Purpose This paper aims to examine predictors (personality, belief systems, expertise and response time) of detecting online romance scams. Design/methodology/approach The online study asked 261 participants to rate whether a profile was a scam or a genuine profile. Participants were also asked to complete a personality inventory, belief scales and demographic, descriptive questions. The online study was also designed to measure response time. Findings It was found that those who scored low in romantic beliefs, high in impulsivity, high in consideration of future consequences, had previously spotted a romance scam and took longer response times were more likely to accurately distinguish scams from genuine profiles. Notably, the research also found that it was difficult to detect scams. The research also found that it was important to adapt Whitty’s (2013) “Scammers Persuasive Techniques Model” to include a stage named: “human detection of scam versus genuine profiles”. Originality/value This is the first study, to the author’s knowledge, that examines predictors of human accuracy in detecting romance scams. Dating sites and government e-safety sites might draw upon these findings to help improve human detection and protect users from this financial and psychologically harmful cyberscam.

scholarly journals Response time of an avian prey to a simulated hawk attack is slower in darker conditions, but is independent of hawk colour morph

2019 ◽  
Vol 6 (8) ◽  
pp. 190677 ◽  
Author(s):  
Carina Nebel ◽  
Petra Sumasgutner ◽  
Adrien Pajot ◽  
Arjun Amar
Keyword(s):  
Response Time ◽  
Response Times ◽  
Bright Light ◽  
Light Level ◽  
White Background ◽  
Light Conditions ◽  
Dark Light ◽  
Light Levels ◽  
Columbia Livia ◽  
Colour Morphs

To avoid predation, many species rely on vision to detect predators and initiate an escape response. The ability to detect predators may be lower in darker light conditions or with darker backgrounds. For birds, however, this has never been experimentally tested. We test the hypothesis that the response time of avian prey (feral pigeon Columbia livia f. domestica ) to a simulated hawk attack (taxidermy mounted colour-polymorphic black sparrowhawk Accipiter melanoleucus ) will differ depending on light levels or background colour. We predict that response will be slower under darker conditions, which would translate into higher predation risk. The speed of response of prey in relation to light level or background colour may also interact with the colour of the predator, and this idea underpins a key hypothesis proposed for the maintenance of different colour morphs in polymorphic raptors. We therefore test whether the speed of reaction is influenced by the morph of the hawk (dark/light) in combination with light conditions (dull/bright), or background colours (black/white). We predict slowest responses to morphs under conditions that less contrast with the plumage of the hawk (e.g. light morph under bright light or white background). In support of our first hypothesis, pigeons reacted slower under duller light and with a black background. However, we found no support for the second hypothesis, with response times observed between the hawk-morphs being irrespective of light levels or background colour. Our findings experimentally confirm that birds detect avian predators less efficiently under darker conditions. These conditions, for example, might occur during early mornings or in dense forests, which could lead to changes in anti-predator behaviours. However, our results provide no support that different morphs may be maintained in a population due to differential selective advantages linked to improved hunting efficiencies in different conditions due to crypsis.

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