Dehydration of a layered double hydroxide—C2AH8

Ukrainczyk, Neven; Matusinović, Tomislav; Kurajica, Stanislav; Zimmermann, Boris; Šipušić, Juraj

doi:10.1016/j.tca.2007.07.022

Cited by 150 publications

(83 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The lower temperature exhibits a primary weight loss at 90°C with a secondary shoulder at 132°C, which indicate the presence of CAH 10 and C 2 AH 8 respectively [35], consistent with the phases observed by XRD. A relatively wide range of dehydration temperatures are reported for these phases in the literature [36], however the sequence in which these phases dehydrate remains the same [35]. The gel phase present also dehydrates over a broad temperature range, partially overlapping with the dehydration of the CAH 10 , which further complicates the peak assignment [1].…”

Section: Thermogravimetrymentioning

confidence: 99%

Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders

Chavda

Bernal

Apperley

et al. 2015

Cement and Concrete Research

View full text Add to dashboard Cite

The conversion of hexagonal calcium aluminate hydrates to cubic phases in hydrated calcium aluminate cements (CAC) can involve undesirable porosity changes and loss of strength.Modification of CAC by phosphate addition avoids conversion, by altering the nature of the reaction products, yielding a stable amorphous gel instead of the usual crystalline hydrate products. Here, details of the environments of aluminium and phosphorus in this gel were elucidated using solid-state NMR and complementary techniques. Aluminium is identified in both octahedral and tetrahedral coordination states, and phosphorus is present in hydrous environments with varying, but mostly low, degrees of crosslinking. A 31 P/ 27 Al rotational echo adiabatic passage double resonance (REAPDOR) experiment showed the existence of aluminium-phosphorus interactions, confirming the formation of a hydrated calcium aluminophosphate gel as a key component of the binding phase. This resolves previous disagreements in the literature regarding the nature of the disordered products forming in this system.

show abstract

Section: Thermogravimetrymentioning

confidence: 99%

Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders

Chavda

Bernal

Apperley

et al. 2015

Cement and Concrete Research

View full text Add to dashboard Cite

show abstract

“…Investigations presented by Ukrainczyk et al [1] and Krstulović et al [29] on hydration of CAC with microcalorimetry showed that far less is heat liberated in the early stage when cement and water first come in contact than is the case for Portland cement. Also, higher water to cement ratio increases the heat evolved up to 287 kJ/kg for CAC at early age due to the higher degree of hydration.…”

Section: Exomentioning

confidence: 98%

“…In order to simulate the temperature distribution in a large volume of concrete material, and also to enable full control of the curing of cements in the very early stages of setting and hardening for better durability and functionality of the material in service, the heat evolved during hydration of cementitious materials is a key performance parameter [1]. The heat release profile during the setting and hardening reaction is also This is a preprint of an article published in Journal of Thermal Analysis and Calorimetry.…”

Section: Introductionmentioning

confidence: 99%

Calorimetric study of geopolymer binders based on natural pozzolan

Kani

Allahverdi

Provis

2016

J Therm Anal Calorim

View full text Add to dashboard Cite

“…The reference pan in each case was an empty sealed one (with a tiny hole). The test specimens were not preheated to T = 90 • C and maintained for 30 min before DSC runs, as it had been done in [5] so as not to eliminate the thermal memory effect. Heating and cooling rates (HR, CR) were 5 K·min −1 for testing thermal effects and 10 K · min −1 for testing the apparent specific heat and conducting TG/DTG investigations, respectively.…”

Section: Dsc and Tg/dtg Studiesmentioning

confidence: 99%

“…Commercial paraffin waxes could constitute a good PCM candidate for a latent heat thermal energy storage system (LHTES). Paraffin waxes meet most of the requirements imposed on LHTES (high thermal energy storage density, good thermal and chemical stability, good self-nucleating properties on freezing, little or no supercooling, lack of phase separation, non-toxicity and reasonable price [5]). Commercial paraffin waxes are cheaper than pure paraffin, they have a moderate latent heat of fusion (L ∼ 200 J · g −1 ) resulting from their high degree of crystallinity, and they have relatively wide range of melting temperatures (22 • C ÷ 68 • C) [6].…”

Section: Introductionmentioning

confidence: 99%

Cooling of High-Power LED Lamp Using a Commercial Paraffin Wax

Zmywaczyk

Zbińkowski

Smogór³

et al. 2017

Int J Thermophys

View full text Add to dashboard Cite

Commercial paraffin wax used by Bolsius Nederland B.V. for manufacturing various kinds of candles was applied as a phase-change material (PCM) for cooling a 28 W high-power light emitting diode (LED) panel during its operation. The main problem arising during operation of an LED is thermal management. According to the manufacturer's datasheet specifications (BioSolution Ltd. www.biosolution. pl), the operating temperature range for the LED street lamp UL28W is (−30 • C) to (+40 • C). The object of the present study was an LED panel containing 28 pieces of high-power 1W LEDs connected in series (4 LEDs in each of the 7 rows) mounted on an aluminum plate of dimensions 80 mm by 135 mm. The tested aluminum plate was placed in a block made of aluminum with a hollow compartment containing Bolsius paraffin wax of density 914 kg·m −3 at room temperature. Temperatures were recorded using K-type thermocouples at selected locations of the tested LED panel for several values of the power supplied to it, while utilizing PCM and without it. As the manufacturer of Bolsius wax candles does not provide any data on the thermal properties of the material used, it was necessary to carry out micro-calorimetric research. Thermophysical properties of the paraffin wax such as the apparent specific heat, enthalpy of phase transition and temperature of phase change transition during heating and cooling were determined using the Netzsch DSC 214 Polyma. The Netzsch TG 209F3 Tarsus was used for TG/DTG measurements. DSC investigations revealed the following thermal transitions taking place during the first heating: solid-solid transition (onset 30.4 • C, peak at 40.9 • C), solid-liquid transition (onset 47.7 • C, peak at 54.9 • C, end at 58.3 • C), latent heat of energy storage 201 J · g −1 , apparent specific heat corresponding to peak at 41.5 • C (5.498 J · g −1 · K −1 ). DTG investigations revealed that the decomposition of paraffin wax is a two-step process. At 283 • C there was observed a slightly slower decomposition (9.43 % · min −1 ) than that at 323 • C(12.5 % · min −1 ). The experimental results obtained upon cooling the high-power LED lamp during its operation can be applied to verify results of numerical modeling of the heat transfer problems with phase-change transitions. An attempt at modeling such a problem based on 1D fixed grid with variable time step approach was undertaken in this work.Keywords LED cooling · Paraffin wax · Phase change material · Thermophysical properties Greek

show abstract

Dehydration of a layered double hydroxide—C2AH8

Cited by 150 publications

References 23 publications

Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders

Identification of the hydrate gel phases present in phosphate-modified calcium aluminate binders

Calorimetric study of geopolymer binders based on natural pozzolan

Cooling of High-Power LED Lamp Using a Commercial Paraffin Wax

Contact Info

Product

Resources

About