Observations on brucite formation and the role of brucite in Iowa highway concrete deterioration

2002 ◽  
Vol 8 (2) ◽  
pp. 137-145 ◽  
Author(s):  
Hyomin Lee ◽  
Robert D. Cody ◽  
Anita M. Cody ◽  
Paul G. Spry
Keyword(s):  
Cement Paste ◽  
Direct Evidence ◽  
Crystal Surface ◽  
Conclusive Evidence ◽  
Coarse Grained ◽  
Fine Grained ◽  
Coarse Aggregates ◽  
Concrete Deterioration ◽  
Direct Precipitation

Abstract Iowa highway concretes containing reactive dolomite, (CaMg) 2 CO 3 , aggregate, composed of fine-grained, microporous dolomite, sometimes have service lives of less than 10 years. This premature deterioration may, in part, be caused by expansive forces created by newly formed minerals such as brucite, Mg (OH) 2 , in the cement paste as a result of dedolomitization of reactive dolomite coarse aggregate. Although calcite is the most abundant secondary mineral in cements of poorly-performing concretes, the present study found no evidence that it was expansionary. Brucite is common but less abundant than calcite and occurred chiefly in and near the margins of reactive dolomite in both the aggregate and cement paste of poorly-performing concretes. Most brucite occurs in partially dedolomitized rims around dolomite coarse aggregates. This type of brucite is widely disseminated through the rims, consists of extremely small (<1 m) microcrystalline masses, and was produced by direct precipitation from pore solutions. Smaller amounts of brucite occur in the cement paste. This type is relatively coarse-grained (10 mu m-20 mu m) and most was formed primarily by crystal surface mediated (topochemical) reactions between magnesium-rich pore solutions and portlandite, Ca(OH) 2 . Numerous microcracks are present in cement paste but are not spatially associated with brucite locations. There is no direct evidence for cracking caused by brucite but this is not conclusive evidence against brucite-induced expansion. Brucite is widely disseminated so that expansion at innumerable micro-locations may cause general concrete expansion which should be relieved by cracking at weaker locations in the concretes.

scholarly journals Piezoelectric characterization of lead-free ferroelectric ceramics

2010 ◽  
Vol 4 (3) ◽  
pp. 199-207 ◽  
Author(s):  
Lorena Pardo ◽  
Alvaro García ◽  
Klaus Brebøl ◽  
Lavinia Curecheriu ◽  
Liliana Mitoseriu ◽  
...  
Keyword(s):  
Sol Gel ◽  
Complex Impedance ◽  
Experimental Spectrum ◽  
Lead Free ◽  
Ferroelectric Ceramics ◽  
Coarse Grained ◽  
Shear Mode ◽  
Fine Grained ◽  
Accuracy Test

The challenge to develop high piezoelectric sensitivity and lead-free composition ferro-piezoelectric ceramics has recently dragged new attention to some classic ferroelectrics. Here, Ba(CexTi1-x)O3 (Ce-BT) and 0.94(Bi1/2Na1/2)TiO3-0.06BaTiO3 (BNBT6) ceramics were piezoelectrically characterized from measurements of complex impedance at electromechanical resonances and their analysis by Alemany et al. software. The reconstruction of the spectra for each resonance is used as an accuracy test of the set of calculated coefficients, quantitatively characterized by the regression factor (R2) of such reconstruction to the experimental spectrum. Piezoelectric activity at room temperature (RT) was observed for Ce-BT with x=0.06 and 0.1, ferroelectrics with T(?'max)>RT, but also for x=0.2 with T(?'max)<RT, which confirms its relaxor character (Ps?0 for T?T(?'max)). BNBT6 fine grained ceramics (~1 ?m) were prepared from nanopowder obtained by sol-gel autocombustion. Results obtained for the fine grained ceramic hot-pressed at 800?C for 2 h and recrystallized at 1050?C for 1 h are d33=148 pCN-1 and kp=26.8%. Despite of its lower grain size, the properties of this material are comparable with those reported for coarse grained ceramics obtained by sintering at T>1100?C. Some measurement issues, as the role of the mode coupling on the characterization results, illustrated for the shear mode of a thickness poled plate, are discussed.

scholarly journals Tye’s Theory of the Unconceptual Content of the Perceptual Mental States

Discourse ◽  
2019 ◽  
Vol 5 (4) ◽  
pp. 18-25
Author(s):  
A. I. Ponomarev
Keyword(s):  
Research Work ◽  
Mental States ◽  
Coarse Grained ◽  
Nonconceptual Content ◽  
Conceptual Content ◽  
Fine Grained ◽  
The Third ◽  
Philosophy Of Perception ◽  
Cognitive Research

Introduction. In modern philosophy of perception, the issue of the content of perceptual mental states is actively discussed, in particular the possibility of nonconceptual content is one of the most significant problem. Usually conceptual activity is attributed to thinking, and perception is intended to be non-conceptual. Such an approach may deprive perception of opportunity to serve as a basis for judgment. The paper analyzes Tye’s theory of non-conceptual content of perceptual mental states, which does not deprive the perception of its epistemological function.Methodology and sources. Methodologically, the research work is based on philosophical analysis of modern theories of perception and results of cognitive research.Results and discussion. In accepted terminology, the content of perceptual mental states can be of three types: conceptual, non-conceptual detailed (fine-grained) and nonconceptual coarse (coarse-grained). Tye's position is that perceptual mental states have only the third kind of content. This approach faces a number of objections that are presented in this paper. The analysis of objections shows their surmount ability, thus, it can be concluded that the Tye’s position of nonconceptual content can be considered as reasonable. The main result of the presented research is the presentation of additional grounds for the theory of non-conceptual content of perceptual mental states.Conclusion. The problem of the content of perceptual mental states is crucial for understanding the epistemological role of perception. The theory of non-conceptual content of perceptual mental states provides new insights into perception.

scholarly journals Thermo-Structural Evolution of the Val Malenco (Italy) Peridotite: A Petrological, Geochemical and Microstructural Study

Minerals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 962
Author(s):  
Wenlong Liu ◽  
Yi Cao ◽  
Junfeng Zhang ◽  
Yanfei Zhang ◽  
Keqing Zong ◽  
...  
Keyword(s):  
Strain Localization ◽  
Structural Evolution ◽  
Coarse Grained ◽  
Prograde Metamorphism ◽  
Fine Grained ◽  
Tectonic History ◽  
Serpentinized Peridotite ◽  
Geochemical Study ◽  
Dissolution And Precipitation

The Val Malenco peridotite massif is one of the largest exposed ultramafic massifs in Alpine orogen. To better constrain its tectonic history, we have performed a comprehensive petro-structural and geochemical study. Our results show that the Val Malenco serpentinized peridotite recorded both pre-Alpine extension and Alpine convergence events. The pre-Alpine extension is recorded by microstructural and geochemical features preserved in clinopyroxene and olivine porphyroblasts, including partial melting and refertilisation, high-temperature (900–1000 °C) deformation and a cooling, and fluid-rock reaction. The following Alpine convergence in a supra-subduction zone setting is documented by subduction-related prograde metamorphism features preserved in the coarse-grained antigorite and olivine grains in the less-strained olivine-rich layers, and later low-temperature (<350 °C) serpentinization in the fine-grained antigorite in the more strained antigorite-rich layers. The strain shadow structure in the more strained antigorite-rich layer composed of dissolving clinopyroxene porphyroblast and the precipitated oriented diopside and olivine suggest dissolution and precipitation creep, while the consistency between the strain shadow structure and alternating less- and more-strained serpentinized domains highlights the increasing role of strain localization induced by the dissolution-precipitation creep with decreasing temperature during exhumation in Alpine convergence events.

scholarly journals Compaction Characteristics and Minimum Void Ratio Prediction Model for Gap-Graded Soil-Rock Mixture

2018 ◽  
Vol 8 (12) ◽  
pp. 2584 ◽  
Author(s):  
Tao Wang ◽  
Sihong Liu ◽  
Yan Feng ◽  
Jidu Yu
Keyword(s):  
Prediction Model ◽  
Void Ratio ◽  
Particle Breakage ◽  
Coarse Grained ◽  
Test Results ◽  
Inhomogeneous Materials ◽  
Compaction Characteristics ◽  
Fine Grained ◽  
Compaction Test

Gap-graded soil-rock mixtures (SRMs), composed of coarse-grained rocks and fine-grained soils particles, are very inhomogeneous materials and widely encountered in geoengineering. In geoengineering applications, it is necessary to know the compaction characteristics in order to estimate the minimum void ratio of gap-graded SRMs. In this paper, the void ratios of compacted SRMs as well as the particle breakage during vibrating compaction were investigated through a series of vibrating compaction tests. The test results show that gap-graded SRMs may reach a smaller void ratio than the SRM with a continuous gradation under some circumstances. When the particles in a gap interval play the role of filling components, the absence of them will increase the void ratio of the SRM. The particle breakage of gap-graded SRMs is more prominent than the SRM with continuous gradation on the whole, especially at the gap interval of 5–20 mm. Based on the test results, a minimum void ratio prediction model incorporating particle breakage during compaction is proposed. The developed model is evaluated by the compaction test results and its validation is discussed.

scholarly journals Controlling the high temperature deformation behavior and thermal stability of ultra-fine-grained W by re alloying

2021 ◽  
Author(s):  
Johann Kappacher ◽  
Oliver Renk ◽  
Daniel Kiener ◽  
Helmut Clemens ◽  
Verena Maier-Kiener
Keyword(s):  
High Temperature ◽  
Peierls Stress ◽  
Coarse Grained ◽  
High Temperature Deformation ◽  
Temperature Deformation ◽  
Fine Grained ◽  
Boundary Interaction ◽  
Kink Pair ◽  
Fine Grain

Abstract Due to their outstanding properties, ultra-fine-grained tungsten and its alloys are promising candidates to be used in harsh environments, hence it is crucial to understand their high temperature behavior and underlying deformation mechanisms. Therefore, advanced nanoindentation techniques were applied to ultra-fine-grained tungsten–rhenium alloys up to 1073 K. A continuous hardness decrease up to 0.2 $$T_{\text{m}}$$ T m is rationalized by a still dominating effect of the Peierls stress. However, the absence of well-established effects of Rhenium alloying, resulting in a reduced temperature dependence of strength for coarse-grained microstructures, was interpreted as an indication for a diminishing role of kink-pair formation in ultra-fine-grained metals with sufficiently fine grain size. Despite slight grain growth in W, dislocation–grain boundary interaction was identified as the dominating deformation mechanism above 0.2 $$T_{\text{m}}$$ T m . Interaction and accommodation of lattice dislocations with grain boundaries was affected by a reduced boundary diffusivity through alloying with Re. Graphic abstract

scholarly journals The Linguistic Formulation of Fallacies Matters: The Case of Causal Connectives

Argumentation ◽  
2020 ◽  
Author(s):  
Jennifer Schumann ◽  
Sandrine Zufferey ◽  
Steve Oswald
Keyword(s):  
Empirical Study ◽  
Coarse Grained ◽  
Controlled Experiments ◽  
Corpus Study ◽  
Fine Grained ◽  
Discourse Connectives

Abstract While the role of discourse connectives has long been acknowledged in argumentative frameworks, these approaches often take a coarse-grained approach to connectives, treating them as a unified group having similar effects on argumentation. Based on an empirical study of the straw man fallacy, we argue that a more fine-grained approach is needed to explain the role of each connective and illustrate their specificities. We first present an original corpus study detailing the main features of four causal connectives in French that speakers routinely use to attribute meaning to another speaker (puisque, étant donné que, vu que and comme), which is a key element of straw man fallacies. We then assess the influence of each of these connectives in a series of controlled experiments. Our results indicate each connective has different effects for the persuasiveness of straw man fallacies, and that these effects can be explained by differences in their semantic profile, as evidenced in our corpus study. Taken together, our results demonstrate that connectives are important for argumentation but should be analyzed individually, and that the study of fallacies should include a fine-grained analysis of the linguistic elements typically used in their formulation.

Correlation between dislocation, grain boundary and interface of duplex SS in stress corrosion cracking(SCC)

1990 ◽  
Vol 48 (4) ◽  
pp. 928-929
Author(s):  
Wang Zheng-fang ◽  
Z.F. Wang
Keyword(s):  
Stainless Steel ◽  
Thermal Cycle ◽  
Secondary Phase ◽  
Corrosion Cracking ◽  
Coarse Grained ◽  
Test Environment ◽  
Fine Grained ◽  
Evaluation Test ◽  
Welding Thermal Cycle ◽  
Micro Analysis

The main purpose of this study highlights on the evaluation of chloride SCC resistance of the material,duplex stainless steel,OOCr18Ni5Mo3Si2 (18-5Mo) and its welded coarse grained zone(CGZ).18-5Mo is a dual phases (A+F) stainless steel with yield strength:512N/mm2 .The proportion of secondary Phase(A phase) accounts for 30-35% of the total with fine grained and homogeneously distributed A and F phases(Fig.1).After being welded by a specific welding thermal cycle to the material,i.e. Tmax=1350°C and t8/5=20s,microstructure may change from fine grained morphology to coarse grained morphology and from homogeneously distributed of A phase to a concentration of A phase(Fig.2).Meanwhile,the proportion of A phase reduced from 35% to 5-10°o.For this reason it is known as welded coarse grained zone(CGZ).In association with difference of microstructure between base metal and welded CGZ,so chloride SCC resistance also differ from each other.Test procedures:Constant load tensile test(CLTT) were performed for recording Esce-t curve by which corrosion cracking growth can be described, tf,fractured time,can also be recorded by the test which is taken as a electrochemical behavior and mechanical property for SCC resistance evaluation. Test environment:143°C boiling 42%MgCl2 solution is used.Besides, micro analysis were conducted with light microscopy(LM),SEM,TEM,and Auger energy spectrum(AES) so as to reveal the correlation between the data generated by the CLTT results and micro analysis.

Direct Evidence for the Role of Inhibition in Resolving Interference

2009 ◽  
Author(s):  
M. Karl Healey ◽  
Karen L. Campbell ◽  
Lynn Hasher ◽  
Lynn Ossher
Keyword(s):  
Direct Evidence

Tongues of Fire

2018 ◽  
Author(s):  
Nancy Farriss
Keyword(s):  
Cultural Difference ◽  
Language Contact ◽  
Social Contexts ◽  
Culture Contact ◽  
Rhetorical Strategies ◽  
Southern Mexico ◽  
Fine Grained ◽  
Indigenous Church ◽  
Cultural Gaps

Language and translation governed the creation of Mexican Christianity during the first centuries of colonial rule. Spanish missionaries collaborated with indigenous intellectuals to communicate the gospel in dozens of local languages that had previously lacked grammars, dictionaries, or alphabetic script. The major challenge to translators, more serious than the absence of written aids or the great diversity of languages and their phonetic and syntactical complexity, was the vast cultural difference between the two worlds. The lexical gaps that frustrated the search for equivalence in conveying fundamental Christian doctrines derived from cultural gaps that separated European experiences and concepts from those of the Indians. This study focuses on the Otomangue languages of Oaxaca in southern Mexico, especially Zapotec, and relates their role in the Dominican evangelizing program to the larger frame of culture contact in postconquest Mesoamerica. Fine-grained analysis of translated texts is used to reveal the rhetorical strategies of missionary discourse and combines with an examination of language contact in different social contexts. A major aim is to spotlight the role of the native elites in shaping what emerged as a new form of Christianity. As translators, chief catechists, and parish administrators they made evangelization in many respects an indigenous enterprise and the Mexican church it created an indigenous church.

scholarly journals CHOP-Dependent Stress-Inducible Expression of a Novel Form of Carbonic Anhydrase VI

1999 ◽  
Vol 19 (1) ◽  
pp. 495-504 ◽  
Author(s):  
John Sok ◽  
Xiao-Zhong Wang ◽  
Nikoleta Batchvarova ◽  
Masahiko Kuroda ◽  
Heather Harding ◽  
...  
Keyword(s):  
Carbonic Anhydrase ◽  
Target Gene ◽  
Target Genes ◽  
Direct Evidence ◽  
Nuclear Protein ◽  
Intracellular Form ◽  
Carbonic Anhydrase Vi ◽  
Responsive Element

ABSTRACT CHOP (also called GADD153) is a stress-inducible nuclear protein that dimerizes with members of the C/EBP family of transcription factors and was initially identified as an inhibitor of C/EBP binding to classic C/EBP target genes. Subsequent experiments suggested a role for CHOP-C/EBP heterodimers in positively regulating gene expression; however, direct evidence that this is the case has so far not been uncovered. Here we describe the identification of a positively regulated direct CHOP-C/EBP target gene, that encoding murine carbonic anhydrase VI (CA-VI). The stress-inducible form of the gene is expressed from an internal promoter and encodes a novel intracellular form of what is normally a secreted protein. Stress-induced expression of CA-VI is both CHOP and C/EBPβ dependent in that it does not occur in cells deficient in either gene. A CHOP-responsive element was mapped to the inducibleCA-VI promoter, and in vitro footprinting revealed binding of CHOP-C/EBP heterodimers to that site. Rescue of CA-VIexpression in c/ebpβ−/− cells by exogenous C/EBPβ and a shorter, normally inhibitory isoform of the protein known as LIP suggests that the role of the C/EBP partner is limited to targeting the CHOP-containing heterodimer to the response element and points to a preeminent role for CHOP in CA-VI induction during stress.

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