scholarly journals Behavior of mortars with different types of cement when induced to Delayed Ettringite Formation (DEF)

2021 ◽  
Vol 11 (3) ◽  
pp. 1-16
Author(s):  
Friancieli Tiecher ◽  
Marinês Langoski ◽  
Nicole Hasparyk
Keyword(s):  
Chemical Reaction ◽  
Curing Temperature ◽  
Delayed Ettringite Formation ◽  
Microstructural Characteristics ◽  
Evaluation Period ◽  
Ettringite Formation ◽  
Different Types ◽  
Early Strength ◽  
Over Time

The purpose of this paper is to present an evaluation of different types of cement and the incidence of Delayed Ettringite Formation (DEF) through mortar composites cast in the laboratory and exposed to a high curing temperature over a 12-month study period. DEF represents one of the types of Internal Sulfate Attacks (ISA) related to an expansive chemical reaction that occurs inside of concrete involving the sulfates from cement. Experiments involved the assessment of expansions, compressive and tensile strengths as well as microstructural characteristics over time. It was observed that tests performed on mortars and with a specific mix required an extended evaluation period to distinguish the behaviors. Furthermore, high early-strength cement featured the worst binder when faced with DEF.

Heat Curing and Delayed Ettringite Formation

1994 ◽  
Vol 370 ◽  
Author(s):  
M.C. Lewis ◽  
Karen L. Scrivener ◽  
S. Kelham
Keyword(s):  
Heat Treatment ◽  
Elevated Temperature ◽  
X Ray Diffraction ◽  
Delayed Ettringite Formation ◽  
X Ray ◽  
Preliminary Results ◽  
Ettringite Formation ◽  
Heat Curing ◽  
Xrd Studies ◽  
Over Time

AbstractThis paper reports some preliminary results from a study of the effect of elevated temperature curing on mortars and the phenomenon of delayed ettringite formation (DEF). Mortars made from cements with sulphate levels of 3%, 4%, and 5% and with 5% sulphate and added alkali were cured at 20 and 90° C and subsequently stored in water. Expansion measurements showed a pessimum effect with increasing S03 content. Mortars which expanded showed a corresponding decrease in strength. X-ray diffraction (XRD) studies indicated that no ettringite is present after heat treatment but re-forms over time within the material. However, the ultimate levels of ettringite reached do not correspond to the magnitude of expansion observed. X-ray microanalysis shows that immediately after the heat treatment the aluminate species and most of the sulphate species are incorporated within the C-S-H gel. The concentrations of these species decrease during expansion, such that at the end of expansion the amounts remaining correspond to the presence of AFm phase mixed with C-S-H.

Measuring Agency Change Across the Domain of Hypnosis

2019 ◽  
Author(s):  
Vince Polito ◽  
Amanda Barnier ◽  
Erik Woody
Keyword(s):  
Rating Scale ◽  
Sense Of Agency ◽  
Pass Rates ◽  
Current Experiment ◽  
Multidimensional Construct ◽  
Time Points ◽  
Hypnotic Induction ◽  
Different Types ◽  
Over Time ◽  
Postexperimental Inquiry

Building on Hilgard’s (1965) classic work, the domain of hypnosis has been conceptualised by Barnier, Dienes, and Mitchell (2008) as comprising three levels: (1) classic hypnotic items, (2) responding between and within items, and (3) state and trait. The current experiment investigates sense of agency across each of these three levels. Forty-six high hypnotisable participants completed an ideomotor (arm levitation), a challenge (arm rigidity) and a cognitive (anosmia) item either following a hypnotic induction (hypnosis condition) or without a hypnotic induction (wake condition). In a postexperimental inquiry, participants rated their feelings of control at three time points for each item: during the suggestion, test and cancellation phases. They also completed the Sense of Agency Rating Scale (Polito, Barnier, & Woody, 2013) for each item. Pass rates, control ratings, and agency scores fluctuated across the different types of items and for the three phases of each item; also, control ratings and agency scores often differed across participants who passed versus failed each item. Interestingly, whereas a hypnotic induction influenced the likelihood of passing items, it had no direct effect on agentive experiences. These results suggest that altered sense of agency is not a unidimensional or static quality “switched on” by hypnotic induction, but a dynamic multidimensional construct that varies across items, over time and according to whether individuals pass or fail suggestions.

Imagery in the Book of Revelation

2020 ◽  
pp. 52-67
Author(s):  
Konrad Huber
Keyword(s):  
Reception History ◽  
Book Of Revelation ◽  
Imperial Cult ◽  
Emotional Effect ◽  
Greco Roman ◽  
Different Types ◽  
Figurative Speech ◽  
Theological Message ◽  
Over Time ◽  
The Way

The chapter first surveys different types of figurative speech in Revelation, including simile, metaphor, symbol, and narrative image. Second, it considers the way images are interrelated in the narrative world of the book. Third, it notes how the images draw associations from various backgrounds, including biblical and later Jewish sources, Greco-Roman myths, and the imperial cult, and how this enriches the understanding of the text. Fourth, the chapter looks at the rhetorical impact of the imagery on readers and stresses in particular its evocative, persuasive, and parenetic function together with its emotional effect. And fifth, it looks briefly at the way reception history shows how the imagery has engaged readers over time. Thus, illustrated by numerous examples, it becomes clear how essentially the imagery of the book of Revelation constitutes and determines its theological message.

scholarly journals Effect of Calcium Nitrate on the Properties of Portland–Limestone Cement-Based Concrete Cured at Low Temperature

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1611
Author(s):  
Gintautas Skripkiūnas ◽  
Asta Kičaitė ◽  
Harald Justnes ◽  
Ina Pundienė
Keyword(s):  
Compressive Strength ◽  
Cement Paste ◽  
Setting Time ◽  
Calcium Nitrate ◽  
Curing Temperature ◽  
Hardened Concrete ◽  
Cement Pastes ◽  
Initial Setting Time ◽  
Initial Setting ◽  
Early Strength

The effect of calcium nitrate (CN) dosages from 0 to 3% (of cement mass) on the properties of fresh cement paste rheology and hardening processes and on the strength of hardened concrete with two types of limestone-blended composite cements (CEM II A-LL 42.5 R and 42.5 N) at different initial (two-day) curing temperatures (−10 °C to +20 °C) is presented. The rheology results showed that a CN dosage up to 1.5% works as a plasticizing admixture, while higher amounts demonstrate the effect of increasing viscosity. At higher CN content, the viscosity growth in normal early strength (N type) cement pastes is much slower than in high early strength (R type) cement pastes. For both cement-type pastes, shortening the initial and final setting times is more effective when using 3% at +5 °C and 0 °C. At these temperatures, the use of 3% CN reduces the initial setting time for high early strength paste by 7.4 and 5.4 times and for normal early strength cement paste by 3.5 and 3.4 times when compared to a CN-free cement paste. The most efficient use of CN is achieved at −5 °C for compressive strength enlargement; a 1% CN dosage ensures the compressive strength of samples at a −5 °C initial curing temperature, with high early strength cement exceeding 3.5 MPa but being less than the required 3.5 MPa in samples with normal early strength cement.

scholarly journals Effect of scent on comfort of aircraft passengers

Work ◽  
2021 ◽  
Vol 68 (s1) ◽  
pp. S273-S280
Author(s):  
Xinhe Yao ◽  
Yu Song ◽  
Peter Vink
Keyword(s):  
Completion Time ◽  
Aircraft Cabin ◽  
Different Types ◽  
The Relationship ◽  
Over Time

BACKGROUND: Scents may influence the perceived comfort of an environment. There are only a few studies conducted on the relationship between scent and comfort in aircraft cabin. OBJECTIVES: The goal of this research is to explore whether relationships between scents and perceived comfort can be found for passengers in an aircraft cabin. METHODS: 276 participants joined an experiment in a Boeing 737 fuselage. The participants were divided into nine groups and each joined a session for 60 minutes with the exposure to different scents. The effect of the odor was measured by a set of questionnaires at the beginning and at the end of the session. Results of questionnaires were analyzed regarding the effects on the completion time, of the type of scents, of the intensity of the scent and on gender. RESULTS: Significant differences were found at the beginning and at the end of the experiment regarding comfort and emotion, but sometimes no relations could be established. The influence of different scents on comfort/discomfort varied and changed over time. However, in all scenarios, participant’ scores on emotion decreased. Additionally, the added scents influenced the linearity between the changes in comfort and discomfort. CONCLUSIONS: Smell could influence the perceived comfort/discomfort of aircraft passengers over time, and different types of smells have different effects on passengers. The preferences on scents are diverse, which highlights the need for personalization in aircraft cabin design.

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