Theory Of Materials Research Articles

Prediction Model of Concrete Initial Setting Time Based on Stepwise Regression Analysis.

Mass concrete is usually poured in layers. To ensure the interlayer bonding quality of concrete, the lower layer should be kept in a plastic state before the upper layer is added. Ultimately, it will lead to the prediction of concrete setting time as a critical task in concrete pouring. In this experiment, the setting time of concrete in laboratory and field environments was investigated. The equivalent age of concrete at the initial setting was also analyzed based on the maturity theory. Meanwhile, factors affecting the setting time in the field environment were studied by means of multiple stepwise regression analysis. Besides, the interlayer splitting tensile strength of concrete subjected to different temperatures and wind speeds was determined. The results of laboratory tests show that both setting time and interlayer splitting tensile strength of concrete decrease significantly with the increase of air temperature and wind speed. In addition, the equivalent age of concrete at initial setting remains the same when subjected to different temperatures, while it decreases obviously with the increase of wind speed. In the field environment, the equivalent age of concrete at initial setting is greatly different, which is related to the variability of relative humidity and wind speed. The average air temperature and maximum wind speed are the main factors affecting the initial setting time of concrete. Furthermore, a prediction model is established based on the stepwise regression analysis results, which can predict the actual setting state in real-time, and hence controlling the interlayer bonding quality of dam concrete.

Biodiversity as insurance: from concept to measurement and application.

ABSTRACTBiological insurance theory predicts that, in a variable environment, aggregate ecosystem properties will vary less in more diverse communities because declines in the performance or abundance of some species or phenotypes will be offset, at least partly, by smoother declines or increases in others. During the past two decades, ecology has accumulated strong evidence for the stabilising effect of biodiversity on ecosystem functioning. As biological insurance is reaching the stage of a mature theory, it is critical to revisit and clarify its conceptual foundations to guide future developments, applications and measurements. In this review, we first clarify the connections between the insurance and portfolio concepts that have been used in ecology and the economic concepts that inspired them. Doing so points to gaps and mismatches between ecology and economics that could be filled profitably by new theoretical developments and new management applications. Second, we discuss some fundamental issues in biological insurance theory that have remained unnoticed so far and that emerge from some of its recent applications. In particular, we draw a clear distinction between the two effects embedded in biological insurance theory, i.e. the effects of biodiversity on the mean and variability of ecosystem properties. This distinction allows explicit consideration of trade‐offs between the mean and stability of ecosystem processes and services. We also review applications of biological insurance theory in ecosystem management. Finally, we provide a synthetic conceptual framework that unifies the various approaches across disciplines, and we suggest new ways in which biological insurance theory could be extended to address new issues in ecology and ecosystem management. Exciting future challenges include linking the effects of biodiversity on ecosystem functioning and stability, incorporating multiple functions and feedbacks, developing new approaches to partition biodiversity effects across scales, extending biological insurance theory to complex interaction networks, and developing new applications to biodiversity and ecosystem management.

Measuring the Harlem Renaissance: The U.S. Census, African American Identity, and Literary FormOn Sympathetic Grounds: Race, Gender, and Affective Geographies in Nineteenth-Century North America

Measuring the Harlem Renaissance: The U.S. Census, African American Identity, and Literary FormOn Sympathetic Grounds: Race, Gender, and Affective Geographies in Nineteenth-Century North America

Toward More-Than-Human Understandings of Sport and the Environment: A New Materialist Analysis of Everyday Fitness Practices.

Sport and fitness have long been linked with healthy lifestyles, yet most sporting events and consumption practices are highly detrimental to the environment. While academics have examined the harmful effects of sporting mega-events and the production and consumption of sport equipment and clothing, there has been less engagement with the “mundane,” everyday activities of consuming, laundering, and recycling of fitness objects. In this paper, we explore the potential in feminist new materialisms for rethinking the complex relationships between sport, fitness, and the environment. In particular, we explain how our engagement with Karen Barad's theory of agential realism led us to rethink women's habitual fitness practices as connected to environmental degradation. Working with Barad's concept of entanglement, we came to notice new human-clothing-environment relationships, focusing on how athleisure clothing itself is an active, vital force that intra-acts with other non-human (and human) matter within the environment. Adopting a diffractive methodology that included reading interviews with women about their activewear practices, our own experiences, new materialist theory, and environmental literature through each other, we focus on two examples that emerged through this process: laundering and disposal practices. Through these examples, we demonstrate the ways in which new materialisms encouraged us to move toward non-anthropocentric understandings of the sport-environment relationship and toward new ethical practices in our everyday fitness lifestyles.

‘Oohing and ahhing’: The power of thin(g)king in art education research

In this article, we seek to explore what new materialist theory and post-intentional phenomenology bring to art education research. Materiality is contextualized politically and historically, and then applied to an emerging research methodology which attempts to centre the material world as a key participant in an art education dissertation research project. The research site, a creative reuse store, serves as both context and participant as the authors explore the powerful collective agency of materiality in processes of art making. Portions of findings from the project are presented here and a new theory of thin(g)king is discussed.

The Unrealized Potential of Body-Reflexive Practices

Raewyn Connell’s work foregrounds bodies in a way that challenges the social-constructionist orientation that has dominated much of the critical research on masculinities. Yet, her concept of “body-reflexive practices” is one of the least explored aspects of her work. In this commentary, I argue that body-reflexive practices, as the concept is developed inThe Men and the Boys, points in the direction of a potentially productive convergence between masculinity studies and new materialist theories. In its engagement with the nature of bodies underlying the cultural construction of gender, Connell’s work maintains a relevance that has been largely unappreciated. This is especially the case for boys and young men as they develop masculinities in negotiation with their corporeal capacities.

Hauntings Across the Divide: Transdisciplinary Activism, Dualisms, and the Ghosts of Racism in Engineering and Humanities Education.

In this paper, we report on an intervention across continents and disciplines that brought together differently positioned students in South Africa and the USA. A collaboration between our classes—an introductory Geographic Information Systems (GIS) class in South Africa and a composition class in the United States—was facilitated and investigated by us. The point of departure of the intervention was to service socially just and anti-racist pedagogies through experimentation. Drawing on posthumanist, feminist, and new materialist theory, we investigate the hauntings of several prejudices and stereotypical tropes that foster racism. We link the concept of hauntology to Plumwood’s (1993) theorization of dualisms. We then draw a cartography of geomatics education in South Africa, focusing on the subjectification of geomatics graduates in particular and engineering graduates in general. We then zoom to our collaboration, and focus on several interactions amongst the cohorts to show instances of hauntings that perpetuate anti-Black, anti-Muslim, and related silences. We find that analysis of dualisms can highlight racist hauntings, and can also provide guidance on how to flatten hierarchies. Our transdisciplinary activism allows us to harness the positivity of difference to trouble binaries. We conclude with some thoughts on pandemic pedagogy in an unequal world.

The Unrealized Potential of Body-Reflexive Practices

Raewyn Connell’s work foregrounds bodies in a way that challenges the social-constructionist orientation that has dominated much of the critical research on masculinities. Yet, her concept of “body-reflexive practices” is one of the least explored aspects of her work. In this commentary, I argue that body-reflexive practices, as the concept is developed in The Men and the Boys, points in the direction of a potentially productive convergence between masculinity studies and new materialist theories. In its engagement with the nature of bodies underlying the cultural construction of gender, Connell’s work maintains a relevance that has been largely unappreciated. This is especially the case for boys and young men as they develop masculinities in negotiation with their corporeal capacities.

Accounting for Imaginary Presence

Both Husserl and Sartre speak of quasi-presence in their descriptions of the lived experience of imagination, and for both philosophers, accounting for quasi-presence means developing an account of the hyle proper to imagination. Guided by the perspective of fulfillment, Husserl’s theory of imaginary quasi-presence goes through three stages. Having experimented first with a depiction-model and then a perception-model, Husserl’s mature theory appeals to his innovative conception of inner consciousness. This elegant account nevertheless fails to do justice to the facticity and bodily involvement of our imaginary experience. Sartre’s theory of analogon, based on his conception of imaginary quasi-presence as ‘magical’ self-affection, embodies important insights on these issues. Kinesthetic sensations and feelings are the modes in which we make use of own body to possess and be possessed by the imaginary object, thus lending it a semblance of bodily presence.

A Traditional Scientific Perspective on the Integrated Information Theory of Consciousness.

This paper assesses two different theories for explaining consciousness, a phenomenon that is widely considered amenable to scientific investigation despite its puzzling subjective aspects. I focus on Integrated Information Theory (IIT), which says that consciousness is integrated information (as ϕMax) and says even simple systems with interacting parts possess some consciousness. First, I evaluate IIT on its own merits. Second, I compare it to a more traditionally derived theory called Neurobiological Naturalism (NN), which says consciousness is an evolved, emergent feature of complex brains. Comparing these theories is informative because it reveals strengths and weaknesses of each, thereby suggesting better ways to study consciousness in the future. IIT’s strengths are the reasonable axioms at its core; its strong logic and mathematical formalism; its creative “experience-first” approach to studying consciousness; the way it avoids the mind-body (“hard”) problem; its consistency with evolutionary theory; and its many scientifically testable predictions. The potential weakness of IIT is that it contains stretches of logic-based reasoning that were not checked against hard evidence when the theory was being constructed, whereas scientific arguments require such supporting evidence to keep the reasoning on course. This is less of a concern for the other theory, NN, because it incorporated evidence much earlier in its construction process. NN is a less mature theory than IIT, less formalized and quantitative, and less well tested. However, it has identified its own neural correlates of consciousness (NCC) and offers a roadmap through which these NNCs may answer the questions of consciousness using the hypothesize-test-hypothesize-test steps of the scientific method.

Geography sculpts the future, or: escaping—and falling back into—the tyranny of absolute space

ABSTRACT This essay reviews developments in spatial theory since the 1960s to argue that any consideration of possible future worlds must begin from a fully dialectical, and fully materialist theory of space. Much critical social and cultural theory instead begins from as unexamined assumption of absolute space, which is deeply problematic theoretically and especially politically. By contrast, what is necessary is a theory capable of understanding not just that spaces are simultaneously absolute, relative, and relational, but how they are simultaneously absolute, relative, and relational. Fundamental building blocks of such a dialectical theory have been laid down by Henri Lefebvre, David Harvey, Doreen Massey, Neil Smith, and Cindi Katz (among many others), but the theory remains insufficiently materialist. A fully materialist, dialectical theory of space requires the re-introduction of landscape and its opposite, anti-landscape as the key mediating spatial forms. Without this, absolute space will continue its tyrannical reign, and the future geography sculpts one more of constraint than of possibility.

Sustainable Logistics Management Maturity—The Theoretical Assessment Framework and Empirical Results from Poland

Poland is Europe’s leader in international freight transport. The majority of companies in the Polish logistics sector are small-sized enterprises with limited human and material resources, which reduces their ability to implement corporate social responsibility practices. In this paper, we explore the logistics solutions (tools and practices) implemented by companies in the logistics sector to manage their business operations through the prism of the triple bottom line (TBL). We assume that a company might achieve sustainable performance even if it focuses mainly on the implementation of logistics solutions for economic performance, as some of those tools and practices also have an impact on the environmental and social performance without being dedicated to them per se. We define sustainable logistics management maturity (SLMM), as the extent to which a company implements modern logistics solutions (tools and management practices) to improve performance with regard to the economic, environmental, and social dimensions of sustainability. Results from focus group research are presented, where experts have assessed the impact of tools and management practices in logistics management on the economic, environmental, and social dimensions of sustainability. Then, we define the overall sustainable logistics management maturity indicator (OSLMI) to allow comparison and benchmarking between companies in the logistics sector. The maturity theory is applied, as it is a suitable tool for the positioning and benchmarking of companies. Through the conceptual model, we link the capabilities of a company (expressed by the application of the logistics solutions) with factors related to the company’s characteristics (size, business profile, source of capital), and the ability of a company to achieve a certain maturity level. The maturity concept is used here to measure the effectiveness of the performance of companies. We use a database of 190 Polish companies from the logistics industry to verify three research hypotheses. Bayesian statistics is applied to verify the existence of a relation between the level of SLMM and a company’s characteristics (size, scope of economic activities, and structure of capital). Statistical analysis proves that the size of a company and the type of economic activities it engages in affect its ability to achieve a higher degree of maturity.

‘Creative Ferment’: abortion and reproductive agency in Bessie Head’s Personal Choices trilogy

Using original archival research from Amazwi South African Museum of Literature, this article examines representations of abortion in three novels by Bessie Head: When Rain Clouds Gather (1968), Maru (1971)...

New materialisms, sport and the environment: imagining new lines of flight

ABSTRACT Written at a time when new ways of knowing, relating and responding to the environment appear more urgent than ever, this paper explores the potential of using new materialist theory for more-than-human understandings of sport and the environment. The paper consists of three parts. We begin by reviewing key trends in research on sport and the environment, before signaling the recent turn towards new materialist ontological principles to explore the intra-actions between sport, physical leisure and the natural environment. We then turn specifically to feminist new materialisms to examine the important contributions such theoretical strands offer for rethinking human and nonhuman entanglements with the environment. In the third and final part we take inspiration from feminist new materialisms to propose a research imaginary aimed towards opening new ‘lines of flight’ in sport and environment research, praxis and pedagogies, particularly in relation to: (i) methods, (ii) modes of representation, (iii) ethical understandings, and (iv) teaching tools. In so doing, we hope this paper encourages others to explore how feminist new materialist approaches might enable new noticings, vital respondings, and thus feminist ethics and response-abilities to (and with) the environments that our sporting and movement practices are already entangled.

Design and Implementation of Macroeconomic Situation Analysis Application System Based on J2EE Technology

It is of great significance to analyze the current economic situation, accurately implement policies, and make breakthroughs in key areas. Using advanced information technology, fully using shared economic data resources, using mature basic economic theories and analysis tools, the application system of macro-economic situation analysis is constructed, which can timely and accurately understand the changes of economic information, study and judge the current economic operation situation, crack down on the development constraints, improve the level of public services, and achieve efficient governance It provides real-time technical support. In this paper, combined with work practice, using J2EE technology, the economic situation analysis system construction process of demand analysis, functional design and development are briefly described, and the application prospects of the system are made for the next step.

Bigger cages, longer signifying chains – ideology as structural limitation and discursive practice

ABSTRACT The aim of this paper is to present a materialist approach to the concept of ideology which delineates the latter as discursive practice and structural limitation. The discursive practices of ideology are not reducible to sets of immaterial distorted ideas or simply false consciousness. While ideology misrepresents and naturalises the existing social reality, its representations are neither true nor false. As a material phenomenon that exists in semiotic practices, ideology is fundamentally discursive and constitutes subjects by interpellating individuals and providing subject positions from which the imaginary relations to real social relations can be practically and meaningfully represented. Rather than reflecting or expressing their conditions of production, ideological practices actively produce, reproduce, and transform the very material conditions they arise in. In a first step, the article presents and discusses different Marxian notions of ideology, namely ideology as false consciousness, as structural limitation, and as commodity fetishism. In a next step, aspects of a materialist theory of ideology, which describes the latter as a set of material discursive practices will be outlined. The contribution will propose nine fundamental characteristics of ideology developed throughout the paper.

Inner Harmony as an Essential Facet of Well-Being: A Multinational Study During the COVID-19 Pandemic.

This study aimed to explore the role of two models of well-being in the prediction of psychological distress during the COVID-19 pandemic, namely PERMA and mature happiness. According to PERMA, well-being is mainly composed of five elements: positive emotions, engagement, relationships, meaning in life, and achievement. Instead, mature happiness is understood as a positive mental state characterized by inner harmony, calmness, acceptance, contentment, and satisfaction with life. Rooted in existential positive psychology, this harmony-based happiness represents the result of living in balance between positive and negative aspects of one's life. We hypothesized that mature happiness would be a more prominent protective factor during the present pandemic than the PERMA composite. A total of 12,203 participants from 30 countries responded to an online survey including the Depression Anxiety Stress Scale (DASS-21), the PERMA-Profiler, and the Mature Happiness Scale-Revised (MHS-R). Confirmatory factor analyses indicated that PERMA and mature happiness were highly correlated, but nonetheless, they represented two separate factors. After controlling for demographic factors and country-level variables, both PERMA Well-being and MHS-R were negative predictors of psychological distress. Mature happiness was a better predictor of stress, anxiety, and general distress, while PERMA showed a higher prediction of depression. Mature happiness moderated the relation between the perceived noxious effects of the pandemic and all markers of distress (depression, anxiety, stress, and total DASS-21). Instead, PERMA acted as a moderator in the case of depression and stress. These findings indicate that inner harmony, according to the mature happiness theory, is an essential facet of well-being to be taken into consideration. The results of this study can also orient policies aimed to alleviate the negative effects of the pandemic on mental health through the promotion of well-being.

Can infants adopt underspecified contents into attributed beliefs? Representational prerequisites of theory of mind

Recent evidence suggests that young infants, as well as nonhuman apes, can anticipate others' behavior based on their false beliefs. While such behaviors have been proposed to be accounted by simple associations between agents, objects, and locations, human adults are undoubtedly endowed with sophisticated theory of mind abilities. For example, they can attribute mental contents about abstract or non-existing entities, or beliefs whose content is poorly specified. While such endeavors may be human specific, it is unclear whether the representational apparatus that allows for encoding such beliefs is present early in development. In four experiments we asked whether 15-month-old infants are able to attribute beliefs with underspecified content, update their content later, and maintain attributed beliefs that are unknown to be true or false. In Experiment 1, infants observed as an agent hid an object to an unspecified location. This location was later revealed in the absence or presence of the agent, and the object was then hidden again to an unspecified location. Then the infants could search for the object while the agent was away. Their search was biased to the revealed location (that could be represented as the potential content of the agent's belief when she had not witnessed the re-hiding), suggesting that they (1) first attributed an underspecified belief to the agent, (2) later updated the content of this belief, and (3) were primed by this content in their own action even though its validity was unknown. This priming effect was absent when the agent witnessed the re-hiding of the object, and thus her belief about the earlier location of the object did not have to be sustained. The same effect was observed when infants searched for a different toy (Experiment 2) or when an additional spatial transformation was introduced (Experiment 4), but not when the spatial transformation disrupted belief updating (Experiment 3). These data suggest that infants' representational apparatus is prepared to efficiently track other agents' beliefs online, encode underspecified beliefs and define their content later, possibly reflecting a crucial characteristic of mature theory of mind: using a metarepresentational format for ascribed beliefs.

A Theory of Debt Maturity and Innovation

I propose a theory of debt maturity as an incentive device to motivate innovation when contracts are fundamentally incomplete and shaped by ex-post renegotiation. The financing of innovative firms must balance two goals. On the one hand, since innovation is inherently risky, the entrepreneur must receive adequate protection after failure. Simultaneously, the firm must be liquidated when its assets can be redeployed more efficiently elsewhere. Meeting these two goals can be especially challenging when contracts are incomplete. I show how an appropriate choice of debt maturity, together with ex-post contract renegotiation, embeds a option into the firm's capital structure. The put is exercised when liquidation is efficient, and it partially insures the entrepreneur against failure and thus motivates innovation. The theory has novel empirical implications for the financing patterns of innovative firms.

Spatial characteristics of the human factors of soil erosion at the boundary of political divisions: A spatial approach

Soil erosion leads to the loss of soil fertility, the destruction of surface soil structure, and the loss of land resources, posing serious threats to the ecological environment, food security, and sustainable development. A series of mature soil erosion research theories is available at present, but only a few studies have dealt with the correlation of soil erosion and its influencing factors in a cross section, and research on soil erosion is limited to the interior of regional boundaries. This study aims to introduce a spatial econometric model into the study of soil erosion to explore the spatial characteristics of the human factors of soil erosion at the boundary of political divisions by using 30 provincial administrative regions in China as examples. First, Moran’s I index is used to test the spatial correlation of regional soil erosion as the premise for exploring the characteristics of soil erosion influencing factors. Second, an entire spatial data model is established to analyze the overall spatial characteristics of human factors. Lastly, six conditional spatial models are developed to examine the spatial characteristics of human factors in different subperiods, subregions, and spatial weight matrices (SWMs). The following results are obtained. (1) Regional soil erosion exhibits significant spatial correlation and demonstrates high–high and low–low aggregation characteristics. (2) The human factors of soil erosion, such as population, economy, land use type, and soil and water conservation, exert significant spatial spillover effects that will cross the boundary of political divisions and affect the soil erosion status of adjacent regions. (3) The spatial spillover effects of human factors vary due to different periods, regional development statuses, and SWMs. In conclusion, this study confirms that regional soil erosion exhibits significant spatial characteristics and the human factors of soil erosion exert spatial spillover effects on the boundary of political divisions. In estimating soil erosion, its spatial characteristics and the spatial spillover effects of its influencing factors should be considered to obtain accurate estimation results.