Critical Impulse Research Articles

Seismic capacity evaluation of reinforced concrete moment-resisting frames with steel damper columns using incremental critical pseudo-multi impulse analysis

Steel damper columns (SDCs) are energy-dissipating members that are suitable for reinforced concrete (RC) moment-resisting frames (MRFs) and those often used for multistory housing. In a previous study, the authors proposed an energy-based prediction procedure for the peak and cumulative response of an RC frame building with SDCs. In this procedure, the accuracy of the equivalent velocity of the maximum momentary input energy (VΔE1*)–peak equivalent displacement (D1*max) relationship is essential for improved prediction. In this article, the seismic capacity curve (VΔE1*–D1*max relationship) of RC MRFs with and without SDCs is evaluated using incremental critical pseudo-multi impulse analysis (ICPMIA). In the ICPMIA, which is based on a study by Takewaki and coauthors, the structure is subjected to various intensities of critical pseudo-multi impulsive lateral force. An ICPMIA of planer four 8- and 16-story RC MRFs with and without SDCs is performed to obtain their structural behaviors under various intensities of pulsive input. Then, the seismic capacity curve obtained from the ICMPIA results are compared with the predicted results based on the simplified equations. The main findings of this article are as follows. (i) The seismic capacity curve of RC MRFs without SDCs strongly depends on the number of impulsive lateral forces (Np). As Np increases, the seismic capacity decreases. The predicted seismic capacity curve severely underestimates that obtained from the ICMPIA in the case of large Np. This trend is notable when the level of pinching behavior in the RC members is severe. (ii) In the case of an RC MRF with SDCs, however, the influence of Np on its seismic capacity curve is small. The predicted seismic capacity curve agrees very well with that obtained from the ICMPIA. The influence of the level of pinching behavior in RC members on the seismic capacity curve is small.

Fugitive Truth: Renewing the Public Sphere in the Age of Post-Truth

In the sixty years since the publication of Jürgen Habermas' magnum opus, The Structural Transformation of the Public Sphere, the public sphere now faces a new threat in the era of “post-truth” politics. The preponderance of lies, mis/disinformation, “fake news”, “alternative facts”, conspiracy theories, and the general breakdown of trust in established sources of knowledge and information has led to the fragmentation and deepening polarisation of the public sphere - a situation deliberately promoted by right wing populist forces intent on fighting the “culture wars”. At the same time, the political space is being disrupted, in a different way, through new social movements and radical activism particularly around issues of climate change, inequality, racial injustice, and police violence. My aim is to show how these contemporary forms of dissent are engendering a new “structural” transformation of the public sphere. They create autonomous and critical spaces of collective engagement that call into question the legitimacy of dominant power structures. Understanding this process requires an alternative rendering of the relationship between truth and politics - something I develop through Michel Foucault's rethinking of the critical impulse of the Kantian Enlightenment and his later work on parrhesia.

Influence of acute dietary nitrate supplementation on oxygen delivery/consumption and critical impulse during maximal effort forearm exercise in males: a randomized crossover trial.

Beetroot juice supplementation (BRJ) should increase nitric oxide bioavailability under conditions of muscle deoxygenation and acidosis that are a normal consequence of the maximal effort exercise test used to identify forearm critical impulse. We hypothesized BRJ would improve oxygen delivery:demand matching and forearm critical impulse performance. Healthy males (20.8±2.4 years) participated in a randomized crossover trial between October 2017 and May 2018 (Queen's University, Kingston, ON). Participants completed 10 min of rhythmic maximal effort forearm handgrip exercise 2.5 h post placebo (PL) vs. BRJ (9 completed PL/BRJ vs. 4 completed BRJ/PL) within a 2 week period. Data are presented as mean±SD. There was a main effect of drink (PL>BRJ) for oxygen extraction (P=0.033, ηp2=0.351) and oxygen consumption/force (P=0.017, ηp2=0.417). There was a drink × time interaction (PL>BRJ) for oxygen consumption/force (P=0.035, ηp2=0.216) between 75 and 360s (1.25-6min) from exercise onset. BRJ did not influence oxygen delivery (P=0.953, ηp2=0.000), oxygen consumption (P=0.064, ηp2=0.278), metabolites ((lactate) (P=0.196, ηp2=0.135), pH (P=0.759, ηp2=0.008)) or power-duration performance parameters (critical impulse (P=0.379, d=0.253), W' (P=0.733, d=0.097)). BRJ during all-out handgrip exercise does not influence oxygen delivery or exercise performance. Oxygen cost of contraction with BRJ is reduced as contraction impulse is declining during maximal effort exercise resulting in less oxygen extraction.

Critical pseudo-double impulse analysis evaluating seismic energy input to reinforced concrete buildings with steel damper columns

Steel damper columns (SDCs) are energy-dissipating members that are suitable for reinforced concrete (RC) buildings and are often used for multistory housing. The evaluation of the peak deformation and hysteretic dissipated energy of such building structures is essential for the rational seismic design of RC buildings with SDCs. In a previous study, the authors proposed an energy-based prediction procedure for the peak and cumulative response of an RC frame building with SDCs. In this procedure, the accuracy of the equivalent velocity of the maximum momentary input energy (VΔE1*)–peak equivalent displacement (D1*max) relationship is essential for high quality predictions. In this article, the VΔE1*–D1*max relationships of RC moment-resisting frames with and without SDCs are investigated using a critical pseudo-double impulse (PDI) analysis based on a study by Takewaki and coauthors. The results show that the VΔE1*–D1*max relationship obtained from the critical PDI analysis agrees well with that calculated from the equations proposed in the previous study.

Study on dynamic deformation-damage-ignition mechanism of GAP/RDX/TEGDN propellant

ABSTRACT Investigations on high-energy and low-vulnerability propellants can provide a better understanding for improving the operational effectiveness and survivability of strategic and tactical missiles. In the present study, the dynamic compressive mechanical properties and damage-ignition response mechanism of the GAP/RDX/TEGDN (GRT) propellant under high strain rates have been studied using a split Hopkinson pressure bar apparatus and a high-performance high-speed camera. The experimental results suggested that the mechanical properties of the GRT propellant, in terms of yield stress, initial compressive modulus, and ultimate stress, were greatly affected by the loaded strain rate. The true stress-strain curves exhibited an initial linear elasticity region followed by yielding a subsequent strain hardening and strain softening region stage. It has been found that the yield stress and ultimate stress increased with the strain rates. Moreover, at higher strain rates, the impulse increases significantly, leading to earlier and more intense ignition. The critical strain rate and the critical impulse of the GRT propellant are 5000 s−1 and 13.28 N · s, respectively. A judgment basis for GRT propellant ignition is established. Finally, according to the high-speed images and the posttest SEM images, it has been concluded that the dominant ignition mechanism of GRT propellant is flow at the macroscopic level and internal frictional heating at the mesoscopic level.

Coherent Flow Structures Linked to the Impulse Criterion for Incipient Motion of Coarse Sediment

Incipient motion has been a topic of investigation by researchers, engineers and scientists for more than a century. The main approach for studying sediment entrainment has been the static approach that uses temporal and spatial averaged flow parameters like bed shear stress and stream power to link them indirectly to sediment entrainment. Recent research outputs have shed light on the important role of turbulent fluctuations in the sediment transport process. It is suggested that the approach of using temporal and spatial averaged parameters fails to account for the dynamic and probabilistic nature of the entrainment process, as inherited by flow turbulence. This has led to the introduction of the only dynamic criteria in the literature for studying sediment entrainment, namely the impulse and energy criteria. These criteria take into account both the magnitude and duration of the turbulent flow event used for assessing the conditions that can result in sediment entrainment. In light of this, this work aims to assess whether there is a trend in terms of the type of flow structures that occur in sequence before and after the occurrences of the flow impulses that have resulted in the coarse particle’s entrainment. To achieve this, we conducted a well-controlled laboratory experiment to investigate the incipient motion of a 7 cm diameter instrumented particle. Five runs of the experiment were performed at flowrates close to the threshold of motion. The instrumented particle was equipped with micro-electro-mechanical sensors (MEMS) to accurately measure its inertial dynamics and detect motion. The sensors recorded entrainment events, and these events were stochastically linked to the impulses occurring for the tested flow conditions. Quadrant analysis was used to investigate the type of flow structures that occurred before, during and after the occurrence of quadrant events with an impulse above the critical impulse. The findings herein associate coarse particle entrainments with energetic impulses linked primarily to sweep events (Q4) and secondarily, sequence of sweeps (Q4) and ejections (Q1).

POSTRESEARCH!

The article addresses the situation of research in art institutions and its contradictions. Can postresearch become a critical impulse for artistic research? The proposition of “postresearch” was first introduced in the European context of artistic research when the 9th Bucharest Biennale, “Farewell to Research”, curated by Henk Slager in 2020 was announced. The philosopher Peter Osborne consequently analyzed the concept of postresearch and its self-contradictory claim of wanting to leave the research paradigm.1 He emphasized that artistic research must fulfil a non-administrative function, as does the “concept of art” by neglecting or revising its form. In comparison, higher education standards and academic legitimation processes of artistic research follow stricter standardization rules (e.g., written supplements). If artistic research neither competes with the “concept of art” (whatever that is?) nor acts as a legitimate science or discipline and furthermore does not escape administration, should these practices reclaim their status as art? Within the unresolved question of how to position artistic research between art and science – or more specifically in the humanities – lies also its attraction, its character or junction for crossing disciplines and critical studies. Artistic research has what the theorist Natalie Loveless called a polydisciplinamorious character which can lead future debates from methodo- logical introspection to collaborate in postresearch practices.

The ‘Chok’ of Image ‘Constellations in Themselves’: Reframing Walter Benjamin’s ‘Little History of Photography’ (1931)

This article revisits some of the principal documents and guiding assumptions that have shaped the debate about the significance of Walter Benjamin’s landmark essay ‘Little History of Photography’ (1931) as well as Benjamin’s conception of photography and media discourse at large. Based on a handwritten draft fragment, translated for the first time into English, Benjamin’s earliest documented manuscript passages for ‘Little History of Photography’ are discussed here in detail to argue for an altered significance of the ‘directives’ inherent in ‘photography’s authenticity’. The article reconfigures the relevance of Benjamin’s ‘critically trained gaze’ and the illuminating ‘chok’ discovered by smaller and faster cameras in ‘postures, gestures, and gazes’. It takes a fresh look at Benjamin’s contested contributions to photography theory in his early ‘Little History of Photography’ and in his late 1940 theses ‘On the Concept of History’. The article re-examines the significance of the disruptive ‘static moment of events’ which, for Benjamin, captures revolutionary visual ’seeds of the new’. Reframing such seminal concepts as ‘chok’, ‘aura’ and ‘optical unconscious’, the article salvages critical impulses from Benjamin’s writings to address in productive fashion the multiple crises and challenges of visual culture in the twenty-first century.

Left- and Right-Wing Criticism of Orientalism and the Role of Representations of Cultures in Their Self-Interpretation and Development

Over the past decades orientalism as an approach adopted in Western studies of nonWestern cultures has been subject to major philosophical analysis. The critical impulse that was transmitted by Edward Said to the scientific community in 1978 was powerful enough to create a universal framework. This conceptual framework makes possible both a revisionist point of view toward the West and a Western offensive discourse toward the so-called internal colonization. When we decompose Orientalism into components, for example through hermeneutic analysis, this phenomenon turns out to be one of the justifiably commonplace problems of the representation of nonWestern cultures in Western academic studies. Orientalists and researchers of non-Western cultures are criticized for mechanistic constructivism applied to the Other, but at the same time, conservative ideologists (René Guénon, Oswald Spengler, etc.) tend to draw attention to the fundamental crisis of Western science, its epistemological dysfunction and unnecessitated plurality that does not bring us closer to understanding the essence. However, both approaches unfairly overlook the factor of already exerted constructive influence on non-Western cultures. Orientalism can be seen not only as a form of exploitation, but also as a form of providing a language of self-interpretation, which have had a visible effect on non-Western cultures' understanding of themselves. This article examines the evolution of perceptions of the possibility and necessity of representations of non-Western cultures, as interpreted by the authors who are commonly classified as equally leftand right-wing ones.

Does a single bout maximal effort forearm exercise test for determining critical impulse result in maximal oxygen delivery and consumption in men? A randomized crossover trial.

In a single bout maximal effort isometric forearm handgrip exercise test (maximal effort exercise test, MXT), contraction impulse exhibits exponential decay to an asymptote equivalent to critical impulse (CI). It is unknown whether oxygen delivery (O2del) and consumption () achieved at CI are maximal. Healthy men participated in a randomized crossover trial at Queen's University (Kingston, ON) between October 2017-May 2018. Participants completed an MXT and forearm incremental exercise test to limit of tolerance (IET-LOT) (7 completed MXT followed by IET-LOT vs. 4 completed IET-LOT followed by MXT) within a 2 week period. Data are presented as mean±standard deviation. Maximal forearm blood flow (FBF) and O2del were not different in 11 men (21±2.5 years) between MXT and IET-LOT (FBF = 473.8±132.2mL/min vs. 502.3±152.3mL/min; P=0.482, ηp2=0.015; O2del = 85.2±23.5mL/min vs. 92.2±37.0mL/min; P=0.456, ηp2=0.012). However, MXT resulted in greater maximal than IET-LOT (44.5±15.2mL/min>36.8±11.4mL/min; P=0.007, ηp2=0.09), due to greater oxygen extraction (54.0±10.0% > 44.4±8.6%; P=0.021, ηp2=0.185). As CI was 88.6±8.2% of IET-LOT contraction impulse, maximal O2 cost of contractions in MXT was greater than IET-LOT (0.45±0.14mL/min/Ns>0.33±0.09mL/min/Ns; P<0.001, ηp2=0.166). In healthy men, MXT identifying CI results in similar peak oxygen delivery but greater peak via increased extraction compared to an IET-LOT, indicating increased oxygen cost. MXT-CI may better estimate maximal than traditional IET-LOT for this exercise modality.

Дезактивация теологии: Агамбен и постсекулярность

Within the framework of postsecular discourse, Giorgio Agamben’s thought occupies an unobvious position: on the one hand, his philosophical project is inextricably linked to the theological tradition of thought; on the other hand, his thought is nourished by a critical impulse that is often labeled atheistic. The ambiguity of such a position is problematic because of the fact that in a post-secular context, that is, a situation in which all thought casts a theological shadow, a clear idea of what atheistic philosophy is today is lost. In order to understand how Agamben manages to simultaneously accept the premises of postsecularity, not to return to the Enlightenment model of atheism, and to take a critical stance towards religion and theology, the article proposes an analysis of his method. The author seeks to understand the meaning and basis of the attitude of deactivation and neutralization of the theological apparatus constantly found in Agamben’s texts. For this purpose his work The Sacrament of Language. An Archaeology of the Oath is read and seen as the main text that reveals the specificities of Agamben’s relationship with theology. The analysis of this work, as well as Nicole Loraux’s study of the phenomenon of the oath in antiquity, allows us to show how Agamben manages to transcend the boundaries of postsecularity: by identifying the primacy of the experience of language and its attendant divisions in relation to religion, law and politics, Agamben argues that critical procedure must be embodied in a particular use of language. These experiences of use are the practices of philosophy and poetry, which in Agamben’s thought play the role of the basis for the critique of theology. Agamben concretizes these forms of linguistic experience through the notions of profanation and parody, the application of which deactivates the theological apparatus. The article concludes with an illustration of the method of parody through the example of the peculiarity of the reception of Simone Weil’s thought in Agamben’s texts.

非線形オイルダンパーを有する平面骨組モデルのダンパー減衰性能のばらつきに対する地震時応答上限値の簡易評価法

A new uncertainty analysis method is developed for planar frame structure models equipped with oil dampers of linear and nonlinear force-velocity relationships. The structural analysis software SNAP® is collaborated with previously proposed uncertainty analysis method called NURP to obtain the maximum structural response when the damper characteristics are varied. In order to consider the uncertainties in the input, the critical double impulse is employed in addition to standard design ground motions, and we proposed the practical solution to use it in the structural analysis software. The validity of the proposed uncertainty method for frame structure models is investigated by comparing the result with maximum response derived by genetic algorithms. As a simplified method to evaluate the maximum value of the frame structure response, a method that uses a shear model equivalent to the frame structure model is also proposed.

Orienting a Transnational Lived Theology for Asian America: Becoming Friends on the Way

Reflecting on the life and death of Feng Daoyou, one of the victims of the 2021 Atlanta shootings, this article introduces a transnational orientation for discerning lived theology focused on the liminal and contingent natures of Asian American experience applied across cultural and geographical contexts between Asia and America. This orientation is rooted in three traits: an abductive posture toward the unfamiliar; a critical impulse toward nationality and empire; and a co-constructive sensibility that embraces our shared conditions across boundaries. These traits are illustrated with the author's research with mainland Chinese Christian sojourners in Hong Kong and examples from new media outlets that explore transnational links and religious heritages.

‘Humanity rising from the depths of brine’: an oceanic politics in Disney’s Moana

ABSTRACT Disney’s Moana (2016) portrays a village leader’s daughter who leaves her home island and sails across the open ocean to undo a curse spreading across Polynesia in response to a Promethean blunder by the demigod Maui. The film’s popular reception focuses on its representation of Polynesian culture, often placing an emphasis on the corporate history and practices of the Walt Disney Company. This essay instead pursues an ecocritical interrogation of the film. While Disney is perhaps inescapably complicit in economies of ecological destruction and exploitation, the production, aesthetics and narrative of Moana nonetheless offer a critical impulse through what I read as an ecopolitical attentiveness to the natural world. On the level of production, the management of computational capacity and the techniques used in the elaborate rendering of the ocean reflect an acknowledgement both of the complexity of natural phenomena and of the finitude of the resources fuelling the infrastructure of digital animation. The narrative of Moana complements this tension by presenting a fantastical mediation between its eponymous protagonist and her oceanic environment. In doing so, Moana recasts the political role of the female subject in the borderlands of the imperial imaginary, presenting her as an eminently powerful ecopolitical agent.

Muscle contraction force conforms to muscle oxygenation during constant-activation voluntary forearm exercise.

What is the central question of this study? In electrically stimulated skeletal muscle, force production is downregulated when oxygen delivery is compromised and rapidly restored upon oxygen delivery restoration. Whether 'oxygen conforming' of force production occurs during voluntary muscle activation in humans and whether it is exercise intensity dependent remains unknown. What is the main finding and its importance? Here, we show in humans that force at a given voluntary muscle activation does conform to a decrease in oxygen delivery and recovers rapidly and completely with restoration of oxygen delivery. This oxygen-conforming response of contraction force appears to happen only at higher intensities. In electrically stimulated skeletal muscle, force production is downregulated when oxygen delivery is compromised and rapidly restored upon restoration of oxygen delivery in the absence of cellular disturbance. Whether this 'oxygen-conforming' response of force occurs and is exercise intensity dependent during stable voluntary muscle activation in humans is unknown. In 12 participants (six female), handgrip force, forearm muscle activation (EMG), muscle oxygenation and forearm blood flow (FBF) were measured during rhythmic handgrip exercise at forearm EMG achieving 50, 75 or 90% critical impulse (CI). Four minutes of brachial artery compression to reduce FBF by ∼60% (Hypoperfusion) or sham compression (adjacent to artery; Control) was performed during exercise. Sham compression had no effect. Hypoperfusion rapidly reduced muscle oxygenation at all exercise intensities, resulting in contraction force per muscle activation (force/EMG) progressively declining over 4min by ∼16% at both 75 and 90% CI. No force/EMG decline occurred at 50% CI. Rapid restoration of muscle oxygenation after compression was closely followed by force/EMG such that it was not different from Control within 30s for 90% CI and after 90s for 75% CI. Our findings reveal that an oxygen-conforming response does occur in voluntary exercising muscle in humans. Within the exercise modality and magnitude of fluctuation of oxygenation in this study, the oxygen-conforming response appears to be exercise intensity dependent. Mechanisms responsible for this oxygen-conforming response have implications for exercise tolerance and warrant investigation.

Closed-form critical response of elastic-plastic shear building with viscous damper under pseudo-double impulse for simulating resonant response under near-fault fling-step motion

A set of approximate closed-form solutions of the maximum interstory drifts under the critical pseudo-double impulse (PDI) is derived for non-proportionally damped multi-story shear building models with bilinear hysteresis. The use of PDI and the closed-form solutions efficiently and accurately enable the capture of the critical responses of elastic-plastic multi-degree-of-freedom (MDOF) systems under the one-cycle sine wave, which substitutes for the main part of near-fault fling-step motions. The formulation of the closed-form maximum interstory drifts is based on the energy balance law. In the formulation, a quadratic function approximation of the damping force-interstory drift relation is introduced together with an updated mode-controlled energy-based approach (UMEA). While UMEA was proposed in the previous paper to derive the approximate maximum interstory drifts of undamped elastic-plastic MDOF systems under the critical PDI, it is extended so that it can be applied to non-proportionally damped MDOF systems. It is demonstrated that the proposed method can estimate the maximum interstory drifts of elastic-plastic non-proportionally damped MDOF systems under the critical PDI and the corresponding one-cycle sine wave with high accuracy. The estimation by the proposed method can be conducted much more efficiently and stably than the time-history response analysis (THRA). It is also shown that the hysteretic energy dissipation is not large enough to reduce the maximum interstory drifts. Finally, it is demonstrated that the proposed method can accurately estimate the maximum interstory drifts of elastic-plastic moment-resisting frames with viscous dampers under the resonant one-cycle sine wave.

University Studies, Up Close and Critical

University Studies, Up Close and Critical Ben Chappell (bio) COMPLAINT! By Sara Ahmed. Durham, NC: Duke University Press. 2021. THE ADJUNCT UNDER-CLASS: How America’s Colleges Betrayed Their Faculty, Their Students, and Their Mission. By Herb Childress. Chicago: University of Chicago Press. 2019. BEYOND EDUCATION: Radical Studying for Another World. By Eli Meyerhoff. Minneapolis: University of Minnesota Press. 2019. LEAN SEMESTERS: How Higher Education Reproduces Inequity. By Sekile M. Nzinga. Baltimore: Johns Hopkins University Press. 2020. [End Page 55] Over a couple of decades now, scholars in the emergent field of critical university studies have deployed the analytics of humanities and social science scholarship to take stock of their own profession and workplaces. This work contrasts with other public debates on the nature and purpose of higher education, whether those advancing “best practices” for accommodating changing social circumstances or issuing calls for large-scale, “disruptive” restructuring, both of which often proceed on the assumption that the limitations of the present and future sociopolitical contexts are to be simply taken for granted. The “critical” marker signifies instead a project that proceeds with the assumption that social relations can and ought to be changed. To that end, critical work holds universities up against their own lofty ambitions and claims in order to see, within the context of historical dynamics of hierarchy, what knowledge institutions are actually like. Much of this work has operated within an epochal frame, marking shifts in higher education such as the expanded access afforded by the G.I. Bill after World War II (Newfield 2007), or right-wing reaction to the diversification of student populations and attendant social movements in the 1960s (Ferguson 2017). Another critical impulse has manifested as an interest in how “post-social” tendencies of the neoliberal moment have reshaped knowledge institutions and exerted pressure on subjects trying to inhabit them (Brown 2015). As Abigail Boggs and Nick Mitchell (2018) have observed, a sizable portion of the critical university studies discourse joins in a “crisis consensus” about how university restructuring is ruining a profession that normally would be both good for society and nice work if you can get it. One version of this narrative is captured in the title of Benjamin Ginsberg’s 2011 book The Fall of the Faculty. Ginsberg sees the decline of academia in a loss of autonomy by intellectuals, brought on by an observable “administrative turn” in university organization, neoliberal priorities in budgeting and accounting, and managerialism that takes for granted the aim of “running it like a business.” Yasmin Nair (2014) has critiqued the “class shock” evident in some of these takes as being invested in the fantasy of a certain bourgeois intellectual lifestyle that is not widely possible, and perhaps never has been without the support of unpaid and invisible labor (for example, provided by “professors’ wives” and others not recognized themselves as intellectuals, but who kept the whole ship afloat). Many if not most scholars may recognize their own experiences in these sweeping accounts, but what are those experiences like? Several recent books enrich this conversation by drawing at least partly on interviews to ground their analyses of the fraught landscape of higher education. The result is a dire picture of the cost to individuals who carry on intellectual work despite the harm that can result from their commitment. Close attention to the human effect of the current state and circumstances of universities reinforces the necessity of a critical approach, demonstrating that there is little to be taken for granted, and much that needs to change. [End Page 56] In a book examined more extensively below, Eli Meyerhoff argues that left-wing critiques of university restructuring fall short by maintaining an attachment to what Meyerhoff considers the “romance” of education. This attachment is evident in various genres of narrating the crisis consensus, including jeremiad, a linear narrative of fall from a more pure or authentic past into the current, diminished state, and melodrama, a narrative of villains and heroes. Ginsberg’s book referenced above shows how these narratives can be combined, but in The Adjunct Underclass: How America’s Colleges Betrayed Their Faculty, Their Students, and Their Mission, Herb Childress avoids naming villains by describing the...

Effect of Explosive Shapes (in Sand Buried Condition) on the Failure of a Circular Clamped Plate of Protective Vehicle

Protective vehicles like armoured personnel carriers (APCs) require assessment of failure of structural elements subjected to impulsive load resulting from explosive blast under sand buried conditions. The explosive shape and location of detonation affect the failure in near field region. In the present study, a circular clamped Rolled Homogenous Armour (RHA) steel plate has been modelled using JC strength &amp; damage model and explosive using JWL equation. Initially, the reflected pressure and specific impulse for a fixed quantity of explosive (3.75 kg) of various shapes i.e. sphere, hemisphere, cylinders with Length to Diameter (L/D) ratio varying from 0.1 to 1 were studied for sand buried at a standoff distance of 118.1 mm. Further, studies were extended for cylindrical charges of φ 213.77 mm with conical 120°-150° and hemispherical cavities with radius of R1.2-R1.8. It was observed that, reflected pressure and specific impulse is much higher for hemispherical cavity of R1.2. The permanent deformation obtained using non-dimensional impulse is valid for explosives without cavities. However, the cavity charges produce failure of plate in the central region of the charge. The critical impulse emerges as an important parameter for assessing failure due to cavity charges. In addition, the scale down experiment is conducted to validate the effectiveness of cavity charges. It can be concluded that cavity charge with hemispherical radius of R1.2 can provide highest damage to RHA plates in close standoff distance.

Interpreting Mythorealism: Disenchanted Shijing and Spiritual Crisis in Yan Lianke’s Ballad, Hymn, Ode

“Mythorealism” is a formal literary experiment developed by Yan Lianke, whose 2008 novel Ballad, Hymn, Ode ( Feng ya song) produces a cumulative effect of absurdity that has provoked controversy over the extent to which it offers an effective social critique. In response to the scholarship based on realist readings of the novel, this article analyzes it from a “mythorealistic” perspective. It argues that the mythorealist narrative does not necessarily cancel out Yan’s social commentary but instead transfers his critical impulse to a psychological exploration of marginal intellectuals in a desymbolized society. In particular, this article is concerned with thematic interpretation and the relation between literary form and meaning in Yan’s parody of the Shijing in Ballad, Hymn, Ode. By focusing on Yan’s symbolic representation of sex and disgust, this article investigates how such imagery and motifs speak from their own space to reveal Chinese intellectuals’ spiritual crisis in an academic world pervaded with an instrumentalist ethos.

Closed-form critical response of undamped bilinear hysteretic MDOF system under pseudo-double impulse for estimating resonant response under one-cycle sine wave

Approximate closed-form maximum interstory drifts under the critical pseudo-double impulse (PDI) are derived for undamped multi-story shear building models with bilinear hysteresis by using the proposed updated mode-controlled energy-based approach (UMEA). PDI was proposed in the previous paper to simulate the critical responses of elastic-plastic MDOF models under near-fault fling-step motions. Although a double impulse (DI) is treated as a ground motion, PDI is treated as a set of impulsive lateral forces. PDI excites only the fundamental-mode responses of elastic proportionally-damped MDOF models because the fundamental participation vector is applied to the influence coefficient vector of PDI. UMEA is a kind of displacement control analyses, and the displacement increment, which is proportional to the fundamental mode evaluated by the tangent story stiffnesses, is given to the model. It is demonstrated that UMEA effectively captures the main characteristics of the maximum interstory drifts under the critical PDI and the critical one-cycle sine wave because most of the kinetic energy, which the fundamental mode has just before yielding, is given to the plastic fundamental mode just after yielding except for the case that the post-yielding stiffness is almost zero. The use of UMEA leads to much more efficient estimation of the maximum interstory drifts than the time-history response analysis because UMEA requires only 2N-time evaluations of the elastic and plastic fundamental modes at most for N-story shear mass models with bilinear hysteresis. It is shown through numerical examples that the maximum interstory drifts under the critical PDI and the corresponding one-cycle sine wave correspond well to those evaluated by the proposed method. It is also shown that the correspondence of the responses of elastic-plastic MDOF models under recorded near-fault motions and the estimated responses by the proposed method is fairly good.