Living in the Borderline: Praxis as Personal Engagement at a Critical Distance

2005 ◽  
Author(s):  
M. Reyes Cruz
Keyword(s):  
Critical Distance ◽  
Personal Engagement

Field-assisted ionization theory for microscopists

1994 ◽  
Vol 52 ◽  
pp. 820-821
Author(s):  
Patrick P. Camus
Keyword(s):  
Electric Field ◽  
Electron Tunneling ◽  
Ionization Probability ◽  
Critical Distance ◽  
Tunneling Probability ◽  
Field Ionization ◽  
Radius Of Curvature ◽  
Field Evaporation ◽  
A Value ◽  
Ion Emission

The theory of field ion emission is the study of electron tunneling probability enhanced by the application of a high electric field. At subnanometer distances and kilovolt potentials, the probability of tunneling of electrons increases markedly. Field ionization of gas atoms produce atomic resolution images of the surface of the specimen, while field evaporation of surface atoms sections the specimen. Details of emission theory may be found in monographs.Field ionization (FI) is the phenomena whereby an electric field assists in the ionization of gas atoms via tunneling. The tunneling probability is a maximum at a critical distance above the surface,xc, Fig. 1. Energy is required to ionize the gas atom at xc, I, but at a value reduced by the appliedelectric field, xcFe, while energy is recovered by placing the electron in the specimen, φ. The highest ionization probability occurs for those regions on the specimen that have the highest local electric field. Those atoms which protrude from the average surfacehave the smallest radius of curvature, the highest field and therefore produce the highest ionizationprobability and brightest spots on the imaging screen, Fig. 2. This technique is called field ion microscopy (FIM).

Antonio Negri

2018 ◽  
Author(s):  
Ingrid Diran
Keyword(s):  
Critical Distance ◽  
Middle Voice ◽  
The Subject ◽  
Definition Of ◽  
Antonio Negri

Agamben describes his posture as a reader as one of seeking a text’s Entwicklungsfähigkeit, or capacity for elaboration.1 In examining Agamben’s practices of reading, we can attend to the opposite phenomenon: the counter-elaboration that a text, in having being read by the philosopher, performs upon Agamben’s own thought. This reciprocal elaboration might constitute a paradigm for Agamben’s use of reading, according to his own idiosyncratic definition of use as an event in the middle voice, in which (according to a definition of Benveniste) the subject ‘effects an action only in affecting itself (il effectue en s’affectant)’ (UB 28). With this definition in mind, we could say that Agamben effects a text (he writes) only to the extent that he is also affected by another text (he reads). This is why Agamben’s position as a reader proves particularly important to any assessment of his work, quite aside from the problem of influence or intellectual genealogy. For this same reason, however, assessing Agamben’s relation to Antonio Negri – a figure with whom, by most measures, he is at odds – poses an unexpected challenge: how can Agamben’s thought be a use of Negri? Answering this question means not only assessing the critical distance between the two thinkers, but also taking this distance as a measure, in the Spinozan sense, of mutual affection.

Fatigue Failure Analysis Using the Theory of Critical Distance

2011 ◽  
Vol 462-463 ◽  
pp. 663-667 ◽  
Author(s):  
Ruslizam Daud ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Al Emran Ismail
Keyword(s):  
Stress Concentration ◽  
Fatigue Failure ◽  
Notch Root ◽  
High Stress ◽  
Critical Distance ◽  
Future Research ◽  
Element Analysis ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Elastic Fracture

This paper explores the initial potential of theory of critical distance (TCD) which offers essential fatigue failure prediction in engineering components. The intention is to find the most appropriate TCD approach for a case of multiple stress concentration features in future research. The TCD is based on critical distance from notch root and represents the extension of linear elastic fracture mechanics (LEFM) principles. The approach is allowing possibilities for fatigue limit prediction based on localized stress concentration, which are characterized by high stress gradients. Using the finite element analysis (FEA) results and some data from literature, TCD applications is illustrated by a case study on engineering components in different geometrical notch radius. Further applications of TCD to various kinds of engineering problems are discussed.

scholarly journals Determination of Critical Separation Distance Between Dwellings in Informal Settlements Fire

2021 ◽  
Author(s):  
Yu Wang ◽  
Lesley Gibson ◽  
Mohamed Beshir ◽  
David Rush
Keyword(s):  
Heat Flux ◽  
Informal Settlement ◽  
Informal Settlements ◽  
Fire Risk ◽  
Fire Spread ◽  
Separation Distance ◽  
Flame Length ◽  
Critical Distance ◽  
Fire Disaster ◽  
Critical Separation

AbstractApproximately one billion people across the globe are living in informal settlements with a large potential fire risk. Due to the high dwelling density, a single informal settlement dwelling fire may result in a very serious fire disaster leaving thousands of people homeless. In this work, a simple physics-based theoretical model was employed to assess the critical fire separation distance between dwellings. The heat flux and ejected flame length were obtained from a full-scale dwelling tests with ISO 9705 dimension (3.6 m × 2.4 m × 2.4 m) to estimate the radiation decay coefficient of the radiation heat flux away from the open door. The ignition potential of combustible materials in adjacent dwellings are analyzed based on the critical heat flux from cone calorimeter tests. To verify the critical distance in real informal settlement fire, a parallel method using aerial photography within geographic information systems (GIS), was employed to determine the critical separation distances in four real informal settlement fires of 2014–2015 in Masiphumelele, Cape Town, South Africa. The fire-spread distances were obtained as well through the real fires. The probabilistic analysis was conducted by Weibull distribution and logistic regression, and the corresponding separation distances were given with different fire spread probabilities. From the experiments with the assumption of no interventions and open doors and windows, it was established that the heat flux would decay from around 36 kW/m2 within a distance of 1.0 m to a value smaller than 5 kW/m2 at a distance of 4.0 m. Both experiments and GIS results agree well and suggest the ignition probabilities at distances of 1.0 m, 2.0 m and 3.0 m are 97%, 52% and 5% respectively. While wind is not explicitly considered in the work, it is implicit within the GIS analyses of fire spread risk, therefore, it is reasonable to say that there is a relatively low fire spread risk at distances greater than 3 m. The distance of 1.0 m in GIS is verified to well and conservatively predict the fire spread risk in the informal settlements.

scholarly journals Probabilistic Assessment of Fracture Toughness of Epoxy Resin EPOLAM 2025 Including the Notch Radii Effect

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1857
Author(s):  
Adrián Álvarez-Vázquez ◽  
Miguel Muñiz-Calvente ◽  
Pelayo Fernández Fernández ◽  
Alfonso Fernández-Canteli ◽  
María Jesús Lamela-Rey ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Critical Distance ◽  
Polymer Materials ◽  
Cumulative Distribution ◽  
Probabilistic Assessment ◽  
Apparent Fracture Toughness ◽  
Experimental Campaign ◽  
Failure Assessment ◽  
Alternative Approaches ◽  
Reliable Design

Many design scenarios of components made of polymer materials are concerned with notches as representative constructive details. The failure hazard assessment of these components using models based on the assumption of cracked components leads to over-conservative failure estimations. Among the different alternative approaches proposed that are based on the apparent fracture toughness, KcN is considered. In so doing, the current deterministic underlying concept must be replaced by a probabilistic one to take into account the variability observed in the failure results in order to ensure a reliable design. In this paper, an approach based on the critical distance principle is proposed for the failure assessment of notched EPOLAM 2025 CT samples with each different notch radii (ρ) including a probabilistic assessment of the failure prediction. First, each apparent fracture toughness is transformed into the equivalent fracture toughness for ρ=0 based on the critical distances theory. Then, once all results are normalized to the same basic conditions, a Weibull cumulative distribution function is fitted, allowing the probability of failure to be predicted for different notch radii. In this way, the total number of the specimens tested in the experimental campaign is reduced, whereas the reliability of the material characterization improves. Finally, the applicability of the proposed methodology is illustrated by an example using the own experimental campaign performed on EPOLAM 2025 CT specimens with different notch radii (ρ).

A ‘LESS THAN ENTHUSIASTIC’ FRIENDSHIP: JOHN MORLEY, GEORGE ELIOT, AND GEORGE HENRY LEWES

2020 ◽  
Author(s):  
Kevin A Morrison
Keyword(s):  
Nineteenth Century ◽  
George Eliot ◽  
Middle Age ◽  
Belief System ◽  
Religious Faith ◽  
John Stuart Mill ◽  
Critical Distance ◽  
Auguste Comte ◽  
Liberal Philosophy ◽  
Aesthetic Preferences

Abstract For roughly a decade, John Morley enjoyed a warm and deferential sociality with George Henry Lewes and George Eliot. The basis for their friendship was the positivist philosophy of Auguste Comte, which initially held great appeal to Morley, who had lost his religious faith while studying as an undergraduate at Balliol, Oxford. While Lewes and Eliot’s views on Comte were largely fixed by middle age, Morley, still in his twenties, was searching for a substitute belief system. As Morley began to embrace the liberal philosophy of (and form a friendship with) John Stuart Mill, who had declared himself to be an antagonist of Comte’s, Morley, Lewes, and Eliot increasingly held less in common. This lack of commonality gave Morley the critical distance to reassess the couple both personally and intellectually. Embracing a new philosophy and divergent aesthetic preferences, Morley developed an equivocal view of his friends, roughly two decades his senior. Utilizing letters, diary entries, published writings, and a previously untranslated document in French, this essay provides a complex portrait of an intergenerational friendship among three nineteenth-century intellectuals.

scholarly journals Target Localization via Integrated and Segregated Ranging Based on RSS and TOA Measurements

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 230 ◽  
Author(s):  
Slavisa Tomic ◽  
Marko Beko
Keyword(s):  
State Of The Art ◽  
Hybrid Approach ◽  
Critical Distance ◽  
Heuristic Approach ◽  
Target Localization ◽  
Line Of Sight ◽  
Time Of Arrival ◽  
Individual Measurement ◽  
New Approach ◽  
Non Line Of Sight

This work addresses the problem of target localization in adverse non-line-of-sight (NLOS) environments by using received signal strength (RSS) and time of arrival (TOA) measurements. It is inspired by a recently published work in which authors discuss about a critical distance below and above which employing combined RSS-TOA measurements is inferior to employing RSS-only and TOA-only measurements, respectively. Here, we revise state-of-the-art estimators for the considered target localization problem and study their performance against their counterparts that employ each individual measurement exclusively. It is shown that the hybrid approach is not the best one by default. Thus, we propose a simple heuristic approach to choose the best measurement for each link, and we show that it can enhance the performance of an estimator. The new approach implicitly relies on the concept of the critical distance, but does not assume certain link parameters as given. Our simulations corroborate with findings available in the literature for line-of-sight (LOS) to a certain extent, but they indicate that more work is required for NLOS environments. Moreover, they show that the heuristic approach works well, matching or even improving the performance of the best fixed choice in all considered scenarios.

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