Fracture Mechanics when Studying the Long-Term Strength of Concrete

2019 ◽  
Vol 945 ◽  
pp. 957-962
Author(s):  
I.L. Shubin ◽  
V.V. Dorkin ◽  
P.S. Sultygova
Keyword(s):  
Fracture Mechanics ◽  
Structural Changes ◽  
Structural Integrity ◽  
Term Strength ◽  
Short Term ◽  
Heterogeneous Structures ◽  
Temperature Action ◽  
Heating Up ◽  
Experimental And Theoretical Studies

The results of experimental and theoretical studies of the process of destruction of concrete by the methods of fracture mechanics are considered. Results of studies of long-term strength, durability and deformability of concrete subjected to a preliminary short-term temperature action up to 300° C and 400° C under load and without load are presented. It is shown that after short-term heating up to 300о С the long-term strength of concrete decreases insignificantly. It is established that heating up to 400° C can be considered the boundary of the structural integrity of concrete. The conditions for using the results of these studies in determining the values of a function that characterizes the change in the long-term strength of a material in the mechanics of heterogeneous structures are formulated. The function of the material destruction measure is introduced to describe the nature of the structural changes in the material at a given constant continuous load, and its change for different levels of a continuous load is considered.

Individual differences in white and grey matter structure associated with verbal habits of thought

2019 ◽  
Author(s):  
Justin C. Hayes ◽  
Katherine L Alfred ◽  
Rachel Pizzie ◽  
Joshua S. Cetron ◽  
David J. M. Kraemer
Keyword(s):  
Individual Differences ◽  
White Matter ◽  
Cognitive Processing ◽  
Grey Matter ◽  
Structural Changes ◽  
Structural Integrity ◽  
Diffusion Tensor ◽  
Self Report ◽  
White Matter Tracts

Modality specific encoding habits account for a significant portion of individual differences reflected in functional activation during cognitive processing. Yet, little is known about how these habits of thought influence long-term structural changes in the brain. Traditionally, habits of thought have been assessed using self-report questionnaires such as the visualizer-verbalizer questionnaire. Here, rather than relying on subjective reports, we measured habits of thought using a novel behavioral task assessing attentional biases toward picture and word stimuli. Hypothesizing that verbal habits of thought are reflected in the structural integrity of white matter tracts and cortical regions of interest, we used diffusion tensor imaging and volumetric analyses to assess this prediction. Using a whole-brain approach, we show that word bias is associated with increased volume in several bilateral language regions, in both white and grey matter parcels. Additionally, connectivity within white matter tracts within an a priori speech production network increased as a function of word bias. These results demonstrate long-term structural and morphological differences associated with verbal habits of thought.

scholarly journals Perception and risk of Covid-19 and climate change: investigating analogies in a common framework

2020 ◽  
Vol 3 ◽  
Author(s):  
Antonello Pasini ◽  
Fulvio Mazzocchi
Keyword(s):  
Climate Change ◽  
Structural Changes ◽  
Short Term ◽  
Common Features ◽  
Risk Equation ◽  
Related Risk ◽  
Policy Level ◽  
Common Framework

This paper investigates analogies in the dynamics of Covid-19 pandemic and climate change. A comparison of their common features (such as nonlinearity and inertia) and differences helps us to achieve a correct scientific perception of both situations, increasing the chances of actions for their solutions. Besides, applying to both the risk equation provides different angles to analyse them, something that may result useful especially at the policy level. It shows that not only short-term interventions are needed, but also long-term strategies involving some structural changes. More specifically, it also shows that, even if climate change is probably more critical and long-lasting than the Covid-19 crisis, we still have, at least currently, more options for reducing its related risk.

Effect of notches and short-term overloadings on long-term strength

1970 ◽  
Vol 2 (4) ◽  
pp. 385-387
Author(s):  
A. A. Klypin ◽  
Yu. P. Frolov
Keyword(s):  
Term Strength ◽  
Short Term

Statistical Blight

1982 ◽  
Vol 47 (4) ◽  
pp. 836-851 ◽  
Author(s):  
Sheldon Scheps
Keyword(s):  
Peer Review ◽  
Structural Changes ◽  
Peer Review System ◽  
Review System ◽  
Short Term ◽  
American Antiquity ◽  
Academic Degree ◽  
Certification Examinations

A short-term remedy is proposed in the hope of curtailing the proliferation of statistical and inferential error rife within the published archaeological literature. First, a study by Isbell and Schreiber, one that violates rudimentary quantitative and qualitative analytical precepts, yet nevertheless was published in American Antiquity, is discussed in depth in order to exemplify the extent to which matters have deteriorated within the discipline. Then, this analysis, in conjunction with the various compendia of statistical abuse compiled by numerous professionals within the field, is invoked as support for an argument advocating structural changes in the peer review system. Perhaps such solutions could be implemented until previously proposed long-term solutions, such as David Thomas"s call for compulsory courses and certification examinations to satisfy academic degree requirements, are finally instituted.

scholarly journals The evolving relationship between airline profitability and passenger satisfaction

2013 ◽  
Vol 24 (1) ◽  
pp. 7-21
Author(s):  
Kent N Gourdin
Keyword(s):  
Airline Industry ◽  
Structural Changes ◽  
Business Models ◽  
Quality Model ◽  
Short Term ◽  
The Past ◽  
Management Actions ◽  
Passenger Satisfaction ◽  
The U.S

This paper examines the ongoing evolution of the U.S. airline industry under deregulation. After losing money for most of the past 35 years, carriers have made structural changes to their business models that have proven to be, at least in the short term, very profitable. After delineating these management actions, the paper examines their impact on passengers. The author utilizes the Service Quality Model to analyze the long-term implications of this new operating paradigm for passenger satisfaction. Based on this analysis the paper goes on to suggest several actions management could take to improve satisfaction. Finally, conclusions are offered and areas for additional research suggested.

scholarly journals Global Value Chain Resilience: Understanding the Impact of Managerial Governance Adaptations

2022 ◽  
pp. 000812562110666
Author(s):  
Liena Kano ◽  
Rajneesh Narula ◽  
Irina Surdu
Keyword(s):  
Value Chain ◽  
Structural Changes ◽  
Lessons Learned ◽  
Value Chains ◽  
Global Value Chain ◽  
Short Term ◽  
Initial Shock ◽  
Lead Firm ◽  
The Impact

While COVID-19 has caused significant short-term disruptions in global value chains (GVCs), in the longer run, the pandemic will not be the primary catalyst in GVC evolution. As GVCs recover from the initial shock, managers will make GVC restructuring decisions guided by long-term strategic considerations. This article describes barriers that lead firm managers may encounter when rethinking location/control decisions for value chain activities and suggests that, in addition to structural changes, managerial governance adaptations are instrumental in enhancing GVCs’ long-term resilience. Lessons learned from responding to the pandemic can help managers enhance GVC efficiency in the increasingly uncertain global environment.

scholarly journals Excess copper induces structural changes in cultured photosynthetic soybean cells

2006 ◽  
Vol 33 (11) ◽  
pp. 1001 ◽  
Author(s):  
María Bernal ◽  
Pilar Sánchez-Testillano ◽  
María del Carmen Risueño ◽  
Inmaculada Yruela
Keyword(s):  
Cell Wall ◽  
Structural Changes ◽  
Copper Tolerance ◽  
Copper Stress ◽  
Induced Response ◽  
Cytoplasmic Vacuole ◽  
Cell Nuclei ◽  
Short Term ◽  
Excess Copper

Soybean [Glycine max (L.) Merr.] cell suspensions have the capacity to develop tolerance to excess copper, constituting a convenient system for studies on the mechanisms of copper tolerance. The functional cell organisation changes observed in these cell cultures after both short-term (stressed cells) and long-term (acclimated cells) exposure to 10 μm CuSO4 are reported from structural, cytochemical and microanalytical approaches. Cells grown in the presence of 10 μm CuSO4 shared some structural features with untreated cells, such as: (i) a large cytoplasmic vacuole, (ii) chloroplasts along the thin layer of cytoplasm, (iii) nucleus in a peripheral location exhibiting circular-shaped nucleolus and a decondensed chromatin pattern, and (iv) presence of Cajal bodies in the cell nuclei. In addition, cells exposed to 10 μm CuSO4 exhibited important differences compared with untreated cells: (i) chloroplasts displayed rounded shape and smaller size with denser-structured internal membranes, especially in copper-acclimated cells; (ii) no starch granules were found within chloroplasts; (iii) the cytoplasmic vacuole was larger, especially after long-term copper exposure; (iv) the levels of citrate and malate increased. Extracellular dark-coloured deposits with high copper content attached at the outer surface of the cell wall were observed only in cells exposed to a short-term copper stress. Structural cell modifications, mainly affecting chloroplasts, accompanied the short-term copper-induced response and were maintained as stable characters during the period of adaptation to excess copper. Vacuolar changes accompanied the long-term copper response. The results indicate that the first response of soybean cells to excess copper prevents its entry into the cell by immobilising it in the cell wall, and after an adaptive period, acclimation to excess copper may be mainly due to vacuolar sequestration.

Long-Term Strength of Polymer Blends from Recycled Materials

2013 ◽  
Vol 43 (3) ◽  
pp. 59-66
Author(s):  
R. K. Krastev ◽  
S. Djoumaliisky ◽  
I. Borovanska
Keyword(s):  
Brittle Fracture ◽  
Polymer Blends ◽  
Calculation Method ◽  
High Density Polyethylene ◽  
Tensile Creep ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Term Strength ◽  
Short Term

Abstract This report presents data on the long-term strength of five composites made of plastic waste. They contain low density polyethylene, high density polyethylene, polypropylene and polystyrene (LDPE, HDPE, PP and PS). Long-term strength is determined experimentally by tensile creep to fracture. The experimentally determined long-term strength is compared to predictions for its probabilistic boundaries. The calculation method of these predictions uses data from short-term experiments. The calculated predictions are true for four compositions which exhibit ductile fracture. The composite containing 50 wt.% PS has the greatest strength (of the tested specimens) and has brittle fracture. Its calculated estimate of long-term strength is not consistent with the experimental one.

scholarly journals EL SISTEMA DE FRANJA DE PRECIOS PARA LOS PRODUCTOS AGRÍCOLAS EN EL PACTO ANDINO: DEFINICION DE CAMBIO ESTRUCTURAL

1995 ◽  
pp. 9-26
Author(s):  
Manuel Del Valle ◽  
Keyword(s):  
Structural Change ◽  
Structural Changes ◽  
Band System ◽  
Short Term ◽  
Monte Carlo Test ◽  
International Prices ◽  
El Sistema ◽  
Andean Pact ◽  
Statistical Criteria

It analyzes the structural change in the context of the price band in the Andean Pact in order to advance proposals for the reform of Decision 37.1 so that it can consider the systematic and sustained changes in the international product market. The focus of the work is statistical, since the system is updated using moving averages and statistical criteria. Thirteen time series used in the price band system are analyzed and univariate models are proposed for each one of them. Furthermore, a rule is proposed to define the structural change, and the univariate models obtained are used to prove said rule using Monte Carlo test for the thirteen products. It is concluded that the price band system can be useful to face short-term fluctuations in international prices, as well as long-term adjustments, but it is not prepared to solve problems generated by structural changes, so it can be modified to consider this issue, but the basic principle of the system should be maintained.

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