The dynamic tension at the core of the grammar of schooling

The American system of schooling has been remarkably resistant to change, with most changes coming in the form of tinkering around the edges. Large-scale reform that alters what David Tyack and Larry Cuban (1995) referred to as the “grammar of schooling” has tended to fizzle out. David Labaree suggests that the practices that are most likely to become part of this persistent grammar of schooling, such as the age-graded classroom, are those that align with schools’ social mission and that meet schools’ organizational needs. Those two elements of the grammar of schooling must remain in balance if reform is to succeed.

Book Review: The Circle of the Snake: Nostalgia and Utopia in the Age of Big Tech by Grafton Tanner

Jamie Ranger reviews The Circle of the Snake by Grafton Tanner. The Circle of the Snake grapples with the political consequences of the cultural turn to nostalgia, specifically the dynamic tension between the radical nostalgia required to contest the incessant homogeneity of cultural reproduction and the neoliberal narrative of a nascent digital utopia endemic to our contemporary systems of mediated communication.

Passive Heave Compensator Design and Numerical Simulation for Strand Jack during Lift Operation in Deep Water

In this paper, the passive heave compensator for the strand jack lifting system is studied. An analytical model is developed, which considers the nonlinear characteristic of the compensator stiffness thus as to predict its response under different parameters accurately. This analytical model helps to find the feasible gas volume of the compensator. The comparative analysis is carried out to analyze the influence of key design parameters on the dynamic response of the compensator. In order to evaluate the effectiveness of the compensator, a coupling model of the strand jack lifting system is derived. The compensator efficiency is evaluated in terms of the lifted structure displacement and the strand dynamic tension. The numerical simulations are performed to evaluate the effectiveness of the compensator. Numerical results show that the compensator is able to significantly decrease the tension variation in the strands and the motion of the lifted structure.

Time-dependent reliability and optimal design of scraper chains based on fretting wear process

Purpose This paper aims to present a dynamic reliability model of scraper chains based on the fretting wear process and propose a reasonable structural optimization method. Design/methodology/approach First, the dynamic tension of the scraper chain is modeled by considering the polygon effect of the scraper conveyor. Then, the numerical wear model of the scraper chain is established based on the tangential and radial fretting wear modes. The scraper chain wear process is introduced based on the diameter wear rate. Furthermore, the time-dependent reliability of scraper chains based on the fretting wear process is addressed by the third-moment saddlepoint approximation (TMSA) method. Finally, the scraper chain is optimized based on the reliability optimization design theory. Findings There is a correlation between the wear and the dynamic tension of the scraper conveyor. The unit sliding distance of fretting wear is affected by the dynamic tension of the scraper conveyor. The reliability estimation of the scraper chain with incomplete probability information is achieved by using the TMSA for the method needs only the first three statistical moments of the state variable. From the perspective of the chain drive system, the reliability-based optimal design of the scraper chain can effectively extend its service life and reduce its linear density. Originality/value The innovation of the work is that the physical model of the scraper chain wear is established based on the dynamic analysis of the scraper conveyor. And based on the physical model of wear, the time-dependent reliability and optimal design of scraper chains are carried out.

Building husky men: Strenuous masculinity in post-depression America

Examining American fitness entrepreneurs from the 1930s, this article examines efforts to reform young, and white, masculine identities through new bodybuilding systems. Centred on Mark Berry, Bob Hoffman and Charles Atlas, three of the decade’s most successful entrepreneurs, the article examines the communities, methods and discourses used to attract customers and create a highly specified form of self-fashioning. In doing so, the article highlights the masculine communities and multiplicities of masculinities operating during this decade for American weight trainers. Importantly all three entrepreneurs focused on a very specific kind of American body, and stemming from this, American masculinity. For Berry, ‘husky’ men came to represent men of physical, moral and mental standing. The ability to withstand pain in exercise, to engage in strenuous activity and gain bodyweight was presented as a metric of one’s success in the world. Likewise, Bob Hoffman focused on the ‘weight lifter’, said to be an ambitious young man capable of succeeding in multiple terrains. Finally, there was Charles Atlas, who made ‘he men’ using his system of dynamic tension. In highlighting the lengths young, white, often affluent, American men went to in order to achieve these identities, the article contributes to the growing interest in American masculinities and the fitness systems they used during times of considerable upheaval.

Soil compaction as a factor of soil fertility model correction

In this work we prove that high soil density and the dynamic tension fields cause change in the parameters of other physical fields, affecting soil. Higher soil density lowers MAC for mobile forms of toxic compounds in soils and increases optimums for mobile forms of nutrient elements. Local soil density changes the direction of migrational flows within the soil, it increases energy expenses needed for humus formation and plant development. Topsoil layers press on the underlying layers, which must be accounted for upon forecasting of the dynamics of soil formation processes. The data shows that in the sod-podzolic soils with density of 1.1 and 1.3 gcm-3 the porosity was 53.7 and 47.1%. With low soil density, the amount of mobile zinc and lead was 6.5±1.4 and 8.5±0.9 mgkg-1 under lawns and 25.6±2.5 and 14.6±1.6 mgkg-1 under residential areas. The increasing soil density led to higher energy demand by plants for NPK consumption and root development. Keywords: SOIL DENSITY, DYNAMIC TENSION FIELDS, MAC, SOIL FERTILITY MODELLING

Influences of Two Calculation Methods about Dynamic Tension on Vibration Characteristics of Cable-Bridge Coupling Model

For the cable-bridge coupling model, the dynamic tension of cables is an important parameter to study the vibration characteristics of the model. Based on this concept, two calculation methods about dynamic tension of cables were introduced in great detail, and the influences of these two calculation methods on the vibration characteristics of cable-bridge coupling model were systematically investigated. Firstly, the vibration equation of the cable was derived based on the variational principle for Hamiltonian, and the vibration equation of the bridge deck was obtained by Newton’s law. Then, the vibration equation of the cable and bridge deck was transformed into ordinary differential vibration equation by the Galerkin method. In addition, the differences of the coefficients in the ordinary differential vibration equation obtained by these two calculation methods about dynamic tension were compared, and a parameter analysis was listed. Finally, the resonance mode of the cable-bridge coupling model was analyzed by a multiple scales method, and an example analysis was listed. The results of parameter analysis show that there are obvious differences in the linear coefficient and nonlinear coefficient of the ordinary differential vibration equation obtained by these two calculation methods. The results of example analysis show that, for the cable-bridge coupling model with 1 : 1 resonance, the amplitude of the model would not be different because of the two calculation methods about dynamic tension, but the amplitude of the cable would be affected by the calculation method significantly. It can be found that the research conclusions here can be helpful to the perfection of theoretical modeling and has certain guiding value for practical engineering.

Gender, households and sustainability: Disentangling and re-entangling with the help of ‘work’ and ‘care’

In rich, developed countries, many stakeholders are focusing on households as settings where progress can be made on environmental and sustainability issues. Related research, policies and interventions, however, tend to ignore gender dynamics, thus treating them as irrelevant, or exploit them to achieve sustainability goals. We challenge this regressive treatment and show how household sustainability can be progressive in relation to gender and sustainability simultaneously – doubly progressive. Specifically, we ask: How do gender and sustainability intersect in households? What are the normative implications of these intersections? To answer these questions, we disentangle the perspectives of ‘work’ and ‘care’, drawing on feminist and gender scholarship, and explore both in the domestic setting by focusing on sustainable technologies and sustainable consumption. In this way, the twin normative agendas of equality of work and expansion of care emerge as ways of linking gender and sustainability in households. Our conclusion considers tensions and overlaps between work and care to identify how they can be re-entangled. We argue that re-entangling work and care requires holding them in dynamic tension with care being the context for work and in this way a doubly progressive approach to household sustainability emerges.