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This perspective article delves into the transformative potential of alkali‐activated materials, acid‐activated materials, and geopolymers in mitigating climate change and market challenges. To harness the benefits of these materials, a comprehensive strategy is proposed. This strategy aims to integrate these materials into existing construction regulations, facilitate certification, and promote market access. Emphasizing research and innovation, the article advocates for, increased funding to refine the chemistry and production of these materials, prioritizing low‐cost alternatives and local waste materials. Collaboration between academia and industry is encouraged to expedite technological advances and broaden applications. This article also underscores the need to develop economic and business models emphasizing the long‐term benefits of these materials, including lower life‐cycle costs and reduced environmental impact. Incentivizing adoption through financial mechanisms like tax credits and subsidies is suggested. The strategy also includes scaling up production technology, fostering industrial collaboration for commercial viability, and developing global supply chains. Educational programs for professionals and regulators are recommended to enhance awareness and adoption. Additionally, comprehensive life‐cycle assessments are proposed to demonstrate environmental benefits. The strategy culminates in expanding the applications of these materials beyond construction, fostering international collaboration for knowledge sharing, and thus positioning these materials as essential for sustainable construction and climate change mitigation. [ABSTRACT FROM AUTHOR]

Acid‐based geopolymers are known for their high temperature resistance and good mechanical performances. Some compositions also exhibit water resistance, which make them suitable for outdoor applications. This work aims to understand accurately the steps occurring during the geopolymerization process and focuses on the type of networks forming at early stages of the reaction. The sample, prepared from metakaolin and phosphoric acid, has been analyzed at different durations and temperatures during its solidification, in order to identify which compounds would crystallize. The structural characterizations have been performed using Fourier transform infrared spectroscopy and X‐ray diffraction. Several Al–O–P compounds and especially AlPO4 polymorphs crystallize in these conditions. They belong to three families of aluminophosphates and are a reliable indication of the amorphous organization of the original sample. The first one is similar to the phases that appear in the phase transition sequences of silica, the second one is composed of AlPO4‐based zeolites, and the last one is characterized by the presence of aluminum in an octahedral network. The transitions between the different phases are also discussed. Finally, the water resistance of the calcined samples is improved, and the release of acidic species in the water is limited even after a calcination at low temperature. [ABSTRACT FROM AUTHOR]

The thermal behavior of a model MK based K‐geopolymer (Si/Al = 1.38 and K/Al = 0.68; obtained by alkaline activation of a very pure metakaolin) was investigated between room temperature and 1400°C in order to evaluate its potentiality for high‐temperature applications. The purpose of our study was to monitor the behavior of a geopolymer during a temperature rise in order to better understand its variations with respect to temperature. The works from the present paper focus only variations in the internal structure of the mineral matrix. The results presented here show that the amorphous mineral matrix is preserved up to 900°C. The results also show that there is a densification of the internal structure of tetrahedral network during heating, due to changes in the Q3 environments in fully‐connected Q4 for both silicates and aluminates. Thus, our work provides a new more precise vision of the 3D geopolymeric mineral matrix for which the silicoaluminous network is not exclusively composed of Q4 entities, contrary to what is frequently encountered in the literature before. [ABSTRACT FROM AUTHOR]

The thermal behavior of a model MK‐based K‐geopolymer was investigated between room temperature and 1400°C in order to evaluate its potentiality for high‐temperature applications. The purpose of our study was to monitor the behavior of a geopolymer during a temperature rise in order to better understand its variations with respect to temperature. The works from the present paper focus only changes in the porous network; it follows a first part devoted to variations in the mineral matrix. The results obtained here show that the geopolymer material preserves its porous integrity up to 800°C, while maintaining the reversibility of water exchanges corresponding to about 25 weight percent. Together with the results of part 1, the findings of this study allow us to affirm that geopolymer materials are only very little affected by temperatures up to 800°C, or even 900°C (keeping its mesoporous amorphous structure). [ABSTRACT FROM AUTHOR]

This study presents a new design of a reduced volumetric ultra-wideband (UWB) antenna using innovative dielectric based on the use of geopolymer material which is safe and eco-friendly. The created antenna is intended to radiate in the air. The impedance mismatch due to interface dielectric/air at the aperture of the antenna imposes to choose dielectric material with an appropriate permittivity value. In this study, the authors focus on the experimental protocol that they use to elaborate a dielectric material with suitable dielectric properties over an UWB domain. An experimental phase of dielectric properties assessment is also described. The conceived antenna is inspired by K-antenna which constitutes the starting point of the proposed new antenna design, particularly because of their small dimensions. The antenna is intended to operate in a frequency band ranging from 300 MHz to 3 GHz. The authors demonstrate that the use of an appropriate innovative dielectric material like a geopolymer is an efficient way to reduce the antenna size. Furthermore, the behaviour of the antenna filled with geopolymer is validated using experimental results. [ABSTRACT FROM AUTHOR]

The French national radioactive waste management agency (Andra) is studying the building of a deep geological disposal for High and Intermediate Level radioactive waste. If accepted, the disposal will lead all along the operating period to the excavation of a large amount of host rock, mainly constituted by argillite. With the aim of using this by-product, alkali-activated materials have been prepared and studied, involving two different alkaline silicate sources (solution and powder). In order to increase the thermal resistance, the addition of sand, as filler, has been studied. A standard test and a thermal shock, both up to 800 °C, are used to study the physical stability of the samples under these thermal constraints. Analyses by XRD and SEM allow correlating the thermal resistance to the structural evolution occurring during the thermal tests. It was shown that the alkaline-silicate solution composition is the main parameter to control the reactions during the thermal treatment. The use of the powder-based solution, containing sodium, leads to the formation of more viscous flow and less crystalline phases, which reduces the thermal resistance and the mechanical properties. The addition of filler in the samples increases the resistance to thermal sudden increase, but is not sufficient to obtain a correct resistance to shock. The utilization of flash-calcined argillite, containing carbonate species, gives a better crystallization during the thermal treatment and leads to more cracks but an increase of the mechanical properties. Using, these different compositions, a value of 20 MPa can be reached after thermal treatment. [ABSTRACT FROM AUTHOR]

Geopolymers are inorganic aluminosilicate materials synthesized at room temperature by the activation of metakaolin with an alkaline solution. The comprehension of the structure and the parameters controlling the reactivity of alkaline solutions as well as their interaction with aluminosilicate species is primordial. In this study, based on Raman and FTIR data spectroscopy, wetting angle measurement was investigated as a new technique to evaluate the depolymerization degree of the alkaline solution. Different solutions with different alkali cations (K, Na, Li) and different Si/M molar ratios were studied. The results showed that the cation influences the formation of various reactive species (rings, chains, oligomers). Moreover, the increase of the depolymerization degree of the solution was evidenced by the increase of the wetting angle. The wetting angle of geopolymer mixtures based on different solutions in presence of the same metakaolin was also investigated. Consequently, for a given metakaolin, lower wetting angle value corresponds to the formation of a single geopolymer network. However, higher wetting angles are attributable to the existence of several networks. Thus, the wetting angle can be considered as a parameter to determine the reactivity of alkaline solutions and their interaction with metakaolin. [ABSTRACT FROM AUTHOR]

Geopolymers are amorphous aluminosilicate binders showing good working properties. Despite the large and growing existing literature about these materials, the geopolymerization mechanism and the parameters that can influence still need a better and deeper understanding. The current study explores the effect of alkaline solution and metakaolin reactivities on geopolymer formation. To do this, several geopolymer samples were synthesized from two alkaline solutions and two metakaolins. The structural evolution of the formed geopolymers was investigated using 27Al static NMR and FTIR spectroscopy during the formation. The mechanical properties were measured using compression tests. The NMR data show that the geopolymerization reaction involves the conversion of the Al (V), Al (VI) of metakaolin into Al (IV) under the effect of the alkaline solution. The dissolution and formation rates strongly depend on the reactivity of the used raw materials. Furthermore, a correlation was revealed between the amount of the formed Al (IV) determined from 27Al NMR, the shift values from FTIR and compressive strengths data. The results indicate that the use of a highly reactive alkaline solution and in a lesser extent a highly reactive metakaolin may enhance the formation of the geopolymer network and, consequently, improve the mechanical strengths of the final materials. [ABSTRACT FROM AUTHOR]

Solution precursor plasma spraying (SPPS) is an innovative process for obtaining finely structured coatings from metallic salt solutions. Lanthanum and zirconium precursors were studied in order to understand their influence on the synthesis of lanthanum zirconate (La2Zr2O7) by SPPS. Thermal analysis revealed that the nature of the precursor affected the hydration shell as well as the formation temperature of zirconium oxide (ZrO2). The surface tensions of precursor solutions in various media were investigated and revealed the influence of the nature of the anion. Different solutions of precursor mixtures were used to obtain La2Zr2O7 splats on metallic substrates. A decrease in the surface tension of the solution led to an increase in the size of the splats. Coating mechanisms by SPPS are governed by the nature of the precursors and solvents. [ABSTRACT FROM AUTHOR]

Nitrogen sorption and small- and wide-angle X-ray and neutron scattering techniques were used to study the porous structure of geopolymers, inorganic polymers synthesized by reaction of a strongly alkaline solution and an aluminosilicate source (metakaolin). The effects of aging and the use of alkali activators (Na+, K+) of different sizes were investigated at room temperature. The influence of aging time on the microstructure of both geopolymer matrixes was verified in terms of pore volume and specific surface area. The results suggested a refinement of the porosity and therefore a reduction in the pore volume over time. Regardless of the age considered, some characteristics of the porous network such as pore size, shape and distribution depend on the alkali activator used. Whatever the technique considered, the potassium geopolymer has a greater specific surface area than the sodium geopolymer. According to the scattering results, the refinement of the porosity can be associated with, first, a densification of the solid network and, secondly, a partial closure of the porosity at the nanometre scale. The kinetics are much slower for the sodium geopolymer than for the potassium geopolymer in the six months of observation. [ABSTRACT FROM AUTHOR]

Silver-Russell syndrome (SRS) is characterized by pre- and post-natal growth restriction that spares head growth, feeding difficulties, and variable dysmorphic facial features without major malformations. Hypomethylation of the paternal 11p15 imprinting control region 1 (ICR1) and maternal uniparental disomy of chromosome 7 are found in 50-60% and in 5-10% of SRS patients, respectively. We report on the pre- and post-natal features of three unrelated SRS patients with unusual congenital heart defects (CHDs). Two patients born prematurely had total anomalous pulmonary venous return and died shortly after birth, and a third patient, now 4 years old, had cor triatriatum sinistrum, which was surgically corrected. In all three patients, the underlying molecular defect was 11p15 ICR1 hypomethylation. Based on a large cohort with molecularly proven SRS, the prevalence of CHD in SRS is estimated at 5.5%. We suggest that the occurrence of CHD in SRS with 11p15 ICR1 hypomethylation is not coincidental, but specific to this genotype. © 2013 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Simpson-Golabi-Behmel syndrome (SGBS) is a rare X-linked multiple congenital abnormality/intellectual disability syndrome characterized by pre- and post-natal overgrowth, distinctive craniofacial features, macrocephaly, variable congenital malformations, organomegaly, increased risk of tumor and mild/moderate intellectual deficiency. In 1996, Glypican 3 (GPC3) was identified as the major gene causing SGBS but the mutation detection rate was only 28-70%, suggesting either genetic heterogeneity or that some patients could have alternative diagnoses. This was particularly suggested by some reports of atypical cases with more severe prognoses. In the family reported by Golabi and Rosen, a duplication of GPC4 was recently identified, suggesting that GPC4 could be the second gene for SGBS but no point mutations within GPC4 have yet been reported. In the genetics laboratory in Tours Hospital, GPC3 molecular testing over more than a decade has detected pathogenic mutations in only 8.7% of individuals with SGBS. In addition, GPC4 mutations have not been identified thus raising the question of frequent misdiagnosis. In order to better delineate the phenotypic spectrum of SGBS caused by GPC3 mutations, and to try to define specific clinical criteria for GPC3 molecular testing, we reviewed the clinical features of all male cases with a GPC3 mutation identified in the two molecular laboratories providing this test in France (Tours and Paris). We present here the results of the analysis of 42 patients belonging to 31 families and including five fetuses and three deceased neonates., (Copyright © 2013 Wiley Periodicals, Inc.)

Perlman syndrome is a rare overgrowth syndrome characterized by polyhydramnios with neonatal macrosomia, nephromegaly, distinctive facial appearance, renal dysplasia, nephro-blastomatosis, and predisposition to Wilms tumor (WT). We report on a newborn with prenatal sonographic signs of Perlman syndrome, large fetal ascites, nephromegaly and macrosomia. The clinical course was marked by neonatal distress, renal failure and refractory hypoxemia leading to death at 2 days of life. Renal histologic examination showed bilateral nephroblastomatosis. Genetic or epigenetic alterations of the 11p15 region (involved in the BWS), including mutation of the CDKN1C gene were excluded. No mutation of the GPC3 gene was identified. We review the 28 patients who have been reported with Perlman syndrome. The prognosis of Perlman syndrome is poor with a high neonatal mortality rate. Among the infants who survived beyond the neonatal period, 64% developed a WT and all had a developmental delay. Fetal macrosomia, ascites and polyhydramnios are frequent manifestations. Clinical overlaps with other overgrowth syndromes particularly Beckwith-Wiedemann syndrome and Simpson-Golabi-Behmel syndrome have been emphasized. Perlman syndrome is considered as an autosomal recessive condition. We review 19 patients from seven sibships with parental consanguinity in two families only. The other cases were sporadic. The 28 reported patients had only 10 unaffected sibs. The low percentage of consanguinity among parents is also puzzling for a rare recessive condition. The molecular basis of Perlman syndrome is unknown. (Epi)genetic anomalies of 11p15 and mutations in GPC3 were not studied in most of the previous reports., (Copyright 2008 Wiley-Liss, Inc.)

Here, we report the clinical and molecular analysis of 75 patients with overgrowth and mental retardation, including 45 previously reported cases [Rio et al., 2003; Baujat et al., 2004]. Two groups are distinguished: group I corresponding to patients with recognizable overgrowth syndromes (Sotos syndrome (SS), Weaver syndrome (WS), Beckwith-Wiedemann syndrome, Simpson-Golabi-Behmel syndrome (SGBS), and del(22)(qter) syndrome) (60 cases) and group II corresponding to unclassified cases (15 patients). We investigated NSD1 and GPC3 deletions or mutations, 11p15 abnormalities, and 22qter deletions. Surprisingly, in Group I, two SS patients had 11p15 abnormalities and two patients with Beckwith-Wiedemann syndrome had NSD1 aberrations. In group II, two cases of del(22)(qter) were identified but neither NSD1, 11p15, nor GPC3 abnormalities were detected. These results emphasize the clinical and molecular overlap in overgrowth conditions., (Copyright 2005 Wiley-Liss, Inc.)