Congruent Point Research Articles

PT-symmetry in one-way wormholes

In a recent paper, we studied a modified version of the Einstein–Rosen bridge. This modified bridge is traversable and works as a one-way membrane: a particle on the first sheet falling towards the throat will reach it in finite time (in Eddington coordinates), and will continue its trajectory on the second sheet. In this paper, we show that the particle undergoes a PT-symmetry as it crosses the throat. This could lead to observable effects thanks to an additional ingredient proposed by Einstein and Rosen: congruent points on the two sheets are identified. We propose a bimetric model to realize this identification for our modified bridge

β-CsHg2I5, a compound with rare [Hg2I5] dimers and large optical anisotropy.

Hg-based compounds show abundant structural diversity and distinguished properties. Herein, a new phase transition compound CsHg2I5 was reported. The high-temperature phase β-CsHg2I5 with rare [Hg2I5] dimers was synthesized by the flux method at 573 K, and it shows a reversible phase transition at a low temperature of ∼100 K to form the low-temperature phase α-CsHg2I5. The two phases crystallize in the same P21/c space group, with different crystal structures. β-CsHg2I5 is composed of rare [Hg2I5] dimers and [CsI11] polyhedral units, while α-CsHg2I5 is composed of [Hg4I11] and [CsI10] units. The experimental band gap of β-CsHg2I5 was found to be 2.58 eV. Owing to the presence of [Hg2I5]∞ pseudo-layers, β-CsHg2I5 exhibits large optical anisotropy with a calculated birefringence of 0.132@1064 nm. Meanwhile, β-CsHg2I5 is a congruent compound and the congruent point is ∼481 K. Theoretical calculations indicate that the rare [Hg2I5] dimer is a nonlinear active unit, which can be used as a new fundamental building block for the design of advanced nonlinear optical materials. Moreover, a CsI-HgI2 pseudo-binary diagram was drawn. The results enrich the structural diversity of Hg-based halides and give some insights into the development of new functional materials based on rare [Hg2I5] dimers.

Optical and Thermal Properties of 2-inch Nd3+, Mg2+ Co-doped Near Stoichiometric Lithium Niobate Crystal

The physical properties of near stoichiometric lithium niobate crystals (NSLN) can be improved by adding magnesium. For example, the light damage threshold of NSLN crystals mixed with a small amount of magnesium ions is higher than that of congruent lithium niobate (CLN) crystals mixed with high magnesium [1]. However, the current difficulties also lie in the deviation of SLN crystals from the congruent point, difficulty in growth, size limitation and uneven doping. SLN crystals are still not commercially available, and the size of the crystals is limited to two inches. We use the partial liquid phase method to synthesize polycrystalline materials of co-doped SLN crystals, and successfully solve the problem of uneven doping. The adjustment of process parameters and the use of continuous feeding technology greatly improved the success rate of SLN crystal growth. Then we characterized the grown NSLN crystal on optical and thermal properties.

Sustainable Industrial Parks and their Impact in Ecuador: A Systematic Review of the Literature

Purpose: The objective of this study focused on conducting a systematic literature review (SLR) of Sustainable Industrial Parks (SIPs) and their impact in Ecuador. Theoretical Framework: SIPs are an effective tool for implementing Inclusive and Sustainable Industrial Development (ISID) and are an instrument to increase impact with efficient use of resources and cleaner production. Design/Methodology/Approach: The methodology adhered to three widely accepted steps for a SLR comprising: planning, execution and dissemination of the analysis. The data review period dates from January 1, 2003 to October 31, 2022, using crawlers such as Scopus, ScienceDirect, Web of Science and Dialnet, considering rigorous methods of inclusion and exclusion. Findings: The results of this study have provided evidence towards the design of a Circular Economy (CE) integration model through Industrial Symbiosis (IS), with agent-based modeling (ABM) adapted to the authenticity of the Ecuadorian industry and to manufacturing with a sustainable mentality. Research, Practical & Social implications: This research through the RSL extracted essential information that highlighted and unified different concepts of SIPs, the congruent point of its functionality and the signs of change that Ecuador shows framed under the concept of CE, beginning to an era of transition extinguished mainly to the current four dimensions of sustainability, focused on economic values, environmental, social and political aspects. Originality/Value: The current study contributes to the literature by showing that industrial development involves pollution and reducing it awakens the use of methodologies aimed at satisfying sustainability needs without involving the capacity of future generations.

Growth of Er3+‐doped LiNbO3 thin‐film on LiTaO3 by e‐beam evaporation

AbstractGrowth of Er3+‐doped 100‐nm thick LiNbO3(LN) films on Z‐cut LiTaO3(LT) single‐crystal by e‐beam evaporation and in‐situ anneal at 600–800°C was studied. Crystalline phase, crystallographic orientation, Er3+ spectroscopic properties, constituent element valence states, defects, Er3+ concentration and stoichiometry of the films were characterized. The results show that the films are in LN single‐crystal state and orient along with c crystallographic axis. Constituent elements Li, O and Er are present in their respective single valence states Li+, O2−, Er3+, while the Nb is in two valence states Nb5+ and Nb4+. The films have Li2O‐contents around congruent point. Antisite(NbLi4+) is the major defect. Its concentration decreases, while Li2O‐content, crystallinity degree, and fluorescence intensity increase with increased growth temperature. The presence of Er3+ in the grown films is in the form of LN crystalline phase. Its concentration is considerably lower than that in initial target material because of lower e‐beam evaporation efficiency of heavy Er3+.

Alice in Lizardland: exploring the spatiotemporal speciation and morphological evolutionary rates in the highly diverse microteiid lizards (Squamata: Gymnophthalmidae)

Abstract Macroevolutionary analyses can identify patterns associated with the origin and diversification of species. Here, we gathered currently available genetic and morphological information to explore the diversification dynamics in a highly diverse family of squamate lizards, Gymnophthalmidae. We downloaded the available GenBank data for four genetic markers (12S, 16S, ND4, and c-mos) and generated a dated phylogenetic hypothesis to use as an operational framework. Using our time-calibrated tree, we conducted a Bayesian analysis of macroevolutionary mixtures (BAMM) to explore macroevolutionary patterns for both speciation and phenotypic evolution. For the latter, we included two morphological traits: body size and leg development. We recovered six major clades commonly referred to as subfamilies, whose common ancestor was recovered between 78.15 and 81.68 Myr. Additionally, we found that the major accumulation of extant lineages occurred during the Miocene. Overall, all the evolutionary rates tended to be low, with particular clades exhibiting higher rates and different but not congruent points of acceleration along the tree. These findings indicate that speciation and phenotypic evolution in this lizard group are heterogenic and decoupled, but several pulses of diversification have occurred. Geographically, we found older lineages to be concentrated in the Amazon and the Guiana Shield, whereas higher speciation rates are found in the tropical Andes and its adjacent lowlands.

Nebulised magnesium sulphate as an adjuvant to the treatment of acute exacerbation of COPD: A systematic review and meta-analysis of randomised controlled trials with trial sequential analysis.

The purpose of this meta-analysis was to evaluate the efficacy of nebulised magnesium in the treatment of acute exacerbation of COPD. PubMed and Embase databases were searched for randomised controlled trials comparing any dose of nebulised magnesium sulphate with placebo for treatment of acute exacerbation of COPD, published from database inception till 30 June 2022. Bibliographic mining of relevant results was performed to identify any additional studies. Data extraction and analyses were done independently by review authors and any disagreements were resolved through consensus. Meta-analysis was done using a fixed-effect model at clinically significant congruent time points reported across maximum studies to ensure comparability of treatment effect. Four studies met the inclusion criteria, randomly assigning 433 patients to the comparisons of interest in this review. Pooled analysis showed that nebulised magnesium sulphate improved pulmonary expiratory flow function at 60 minutes after initiation of intervention compared to placebo [median difference (MD) 9.17%, 95% confidence interval (CI) 2.94 to 15.41]. Analysis of expiratory function in terms of standardised mean differences (SMD) revealed a small yet significant positive effect size (SMD 0.24, 95% CI 0.04 to 0.43). Among the secondary outcomes, nebulised magnesium sulphate reduced the need for ICU admission (risk ratio 0.52, 95% CI 0.28 to 0.95), amounting to 61 fewer ICU admissions per 1000 patients. No difference was noted in the need for hospital admission, need for ventilatory support, or mortality. No adverse events were reported. Nebulised magnesium sulphate improves pulmonary expiratory flow function and reduces the need for ICU admission in patients with acute exacerbation of COPD.

Differences in self-other control as cognitive mechanism to characterize theory of mind reasoning in autistic and non-autistic adults.

In cognitive science, altered Theory of Mind is a central pillar of etiological models of autism. Yet, recent evidence, showing comparable Theory of Mind abilities in autistic and non-autistic people, draws a more complex picture and renders previous descriptions of Theory of Mind abilities in autism and their role in autistic symptomatology insufficient. Here, we addressed self-other control as a potential candidate cognitive mechanism to explain subtle Theory of Mind reasoning differences between autistic and non-autistic adults. We investigated flexible shifting between another's and one's own congruent or incongruent points of view, an ability that is important for reciprocal social interaction. Measuring response accuracy and reaction time in a multiple-trial unexpected location false belief task, we found evidence for altered self-other control in Theory of Mind reasoning in autistic adults, with a relative difficulty in flexibly considering the other's perspective and less interference of the other's incongruent viewpoint when their own perspective is considered. Our results add to previous findings that social cognitive differences are there but subtle and constitute one step further in characterizing Theory of Mind reasoning in autism and explaining communication and interaction difficulties with non-autistic people in everyday life.

Structure–property relationship amphoteric oxide systems via phase stability and ionic structural analysis

AbstractThe effects of basicity and amphoteric oxides (Al2O3 and FetO) on the structure–property relationships of CaO–SiO2–(Al2O3 and FetO) and CaO–SiO2–Al2O3–FetO slags were investigated to determine the constitutional effects on the structure of high‐temperature ionic melts. The proportion of Qn species, which is determined by Raman spectroscopy, and the viscosity measured by the rotating cylinder method are both correlated and shown together with the slag structure index (NBO/T) concept. The NBO/T of CaO‐SiO2 binary slags showed a linear relationship with basicity (CaO/SiO2), including an inflection point at CaO/SiO2 = 1.0 resulting from the stability and Qn‐dominant unit of the melt, which changes close to the wollastonite (CaSiO3) congruent point. This inflection point changes with the increasing amphoteric oxide content (Al2O3 and FetO) because of the change in the dominant polymeric unit (Si4+–O–Si4+→M4+–O–Si4+; M: Al and Fe), in accordance with the equilibrated primary phases. As the Al2O3 content increased, the viscosity and activation energy of slags both drastically increased owing to the change in the flow unit (Si–O–Si, Al–O–Si, and Al–O–Al). In contrast, as FetO increased, the viscosity and activation energy (Eη) of slags decreased because of the change in the flow unit (Si–O–Si, Fe–O–Si, and Fe–O–Fe). Ultimately, the flow unit (T–O–T; T = Si, Al, and Fe) and activation energy of the slags were found to be closely related to the solid primary phase on the phase diagram, and the physical‐property–structure relationship was determined from the phase stability.

Microstructure and properties of Ti–Zr congruent alloy fabricated by laser additive manufacturing

Abstract In the present work, Ti40Zr (atomic percent) congruent alloy, as well as four other Ti–Zr alloys near the congruent point, was fabricated using laser additive manufacturing (LAM) on pure titanium substrate. Comparative analyses of these alloys were performed based on microstructure, mechanical properties, tribological properties, corrosion resistance, and formability. The results show that the microstructure of the alloys develops sequentially from the Widmanstatten structure to nearly full β-(TiZr) columnar crystals for 40 at.% Zr, to β-(TiZr) columnar crystals plus granular α-(TiZr) with the increase of Zr addition. The Ti60Zr40 congruent alloy with nearly full β-(TiZr) structure presents a novel combination of ductility, corrosion resistance, and formability, but it has a slightly lower hardness, less strength and poor tribological properties, compared with the other Ti–Zr alloys near the congruent point. Therefore, to develop the congruent alloy as a high strength LAM material through alloying is very significant.

Recherche qualitative en psychanalyse : l’étude du cas de la théorisation ancrée

BackgroundHow can research remain as faithful as possible to the psychoanalytical approach, which proceeds by case study, and at the same time meet the current requirements for scientific validation and publication in clinical psychology? Especially if the project is part of an interdisciplinary context, aiming to bring psychoanalysis – which promotes qualitative analysis – into dialogue with epistemological frameworks that use very different methods such as, for example, quantitative and hypothetical-deductive medicine. Although psychoanalysis was conceived, from its origins, as both a theory of the human psyche and as a therapeutic method seeking to validate its foundations – the hypothesis of the unconscious, analysis and interpretation of the transference on the analyst –, its endogenous validation criteria remain insufficient, from the point of view of research in the human and social sciences where the psychologist-researcher situates her/himself. Even if a translation of the results is possible, a methodology that guarantees objective results accepted by a larger scientific community is required. Our study, wishing to better understand the psychological effects of cancer in adolescence and early adulthood on romantic life and sexuality, had to consider these epistemological concerns. Conceived from its origin in a dual culture – that of medical care and clinical psychology with an analytical orientation –, it led us to use the qualitative methodology of Grounded theory (GT). Our paper aims to show that the use of GT ensures scientific rigor while maintaining the essentials of the psychoanalytical method and process – applied, in this context, to the collection and analysis of data, and to the way of producing results. MethodologyAlthough they come from sociology, we will show that many of the core operators of GT are very close to psychoanalytical ones. For example, inductive and iterative dimensions or the necessary a-theoretical approach of the researcher offer particularly congruent points of contact with the psychoanalytical process, which we will illustrate with concrete examples from our study. ResultsThe inductive, reflexive, and iterative properties of GT are very close to the central operators of the psychoanalytical process while respecting an accepted scientific approach in the social sciences. Promoting co-constructive results and articulating individual and populational scales, they respect both the psychodynamic subjectivity of the participants and the conditions for targeting a scientific approach more generally used in the social sciences. Moreover, using GT in psychoanalytical research fosters translational research and an immediate transfer of scientific knowledge to participants in the field. This is another point of similarity with the psychoanalytical method in which the process itself can be considered as a result. ConclusionGT offers the psychologist-researcher with a psychoanalytical orientation a particularly relevant methodological tool to satisfy many validation conditions of other scientific communities, while respecting his or her epistemological and clinical reference. It is therefore a valuable methodological operator for interdisciplinary research in psychoanalytical psychology.

Para-além da Histeria... O gozo feminino

O objetivo do presente trabalho é distinguir e demarcar os encontros e desencontros entre a histeria, gozo fálico, e a feminilidade, Outro gozo. Sobretudo, elucidar a singularidade de cada forma de gozar. Comumente, confunde-se a estrutura histérica com o gozo feminino; entretanto, a histeria não anula a feminilidade. Pelo contrário, encontramos fenômenos clínicos que demonstram esses entrecruzamentos dos dois gozos. Por isso, os fenômenos do feminino na histeria serão diferentes dos da neurose obsessiva. Além disso, há os que pressupõem que só existem mulheres histéricas, mas sabemos que também há os homens histéricos. Diante disso, já sabemos que existem pontos congruentes entre elas, pois % Mulher comunica-se tanto com o gozo fálico quanto com o Outro gozo. Esta pesquisa teórica busca, por meio dos fenômenos clínicos, percorrer a interseção entre esses dois gozos. Por conseguinte, mostra-se também que, na psicanálise, a histeria é diferente do senso comum, que a entende como uma alteração de emoções, descontrole e gritaria.

How to control the stoichiometry of cadmium telluride thin film for photovoltaic applications

In this study, Bube's growth model for a cadmium telluride (CdTe) polycrystalline thin film was re-examined with a view of avoiding his assumptions that neglect the vapor pressures of Cd and Te2 near the film. We proposed a new thermodynamic growth model based on the fact that there is an experimentally verified characteristic ratio (α) of equilibrium partial pressures PCd/2PTe2 that depends on the temperature T and CdTe stoichiometry. By writing PCd(0)=2α(0)PTe2(0) and PCd(h)=2α(h)PTe2(h), where α(0) is determined by source stoichiometry, we can solve the equations for α(h) and thereby determine the stoichiometry of the CdTe thin film grown under physical vapor deposition (PVD) conditions. Simulation was performed to predict the stoichiometry of the CdTe thin film as a function of source stoichiometry for various source-film temperature combinations. The results show that for a typical CdTe PVD process with Tsource>Tthin film: (1) stable deposition, without a non-stoichiometric composition shift, can be achieved at congruent-growth stoichiometry; (2) any stoichiometric deviation from the congruent sublimation point becomes more substantial (in the same direction) in the thin film than in the source; and (3) larger ΔT between the source and the thin film results in a more composition shift.

Electro-optic coefficients of a non-congruent lithium niobate fabricated by vapour transport equilibration: Composition effect

Abstract Composition effect on electro-optic (EO) properties of a LiNbO3 (LN) single-crystal has been investigated in a Li2O-content range of 47.0–49.95 mol%. Some non-congruent LN crystals with different Li2O-contents were prepared by performing Li-deficient or Li-rich vapour transport equilibration treatments on as-grown congruent LN crystals. Unclamped EO coefficients γ13 and γ33 of these samples were measured by a Mach–Zehnder interferometric method. The measurements show that in the Li-deficient regime both γ13 and γ33 increase by ∼8% as Li2O-content decreases from the congruent 48.6 mol% to the 47.0 mol% in the Li-deficient regime. The feature is desired for the EO application of the Li-deficient crystal. In the near-stoichiometric regime, both γ13 and γ33 reveal a non-monotonic dependence. As the Li2O-content increases from the 48.6 mol%, the EO coefficient decreases. Around Li2O-content 49.5 mol%, a minimum is reached. After that, the EO coefficient recovers slowly. At the stoichiometric composition, it recovers to a value close to that at the congruent point. Comparison shows that different crystal growth methods give rise to different defect structure features and hence different composition effects.

Leaching behaviour of low Ca:Si ratio CaO–SiO2–H2O systems

A dynamic leaching study of the dissolution of low calcium to silicon ratio (C/S) calcium–silicate–hydrate (C–S–H) systems with initial C/S ranging from 0.2 to 0.6 has been undertaken. Dissolution was studied in demineralised water at 25°C to a degree of leaching of 2.5m3kg−1. These C–S–H gels show remarkably similar behaviour during early leaching stages, giving an equilibrated pH of ~9.9 and a solution phase C/S of ~0.29. Over longer times, C–S–H gels with C/S>0.29 evolve, on leaching, towards a congruent dissolution point with a solid C/S close to 0.84 (consistent with tobermorite) and pH~10.8. C–S–H gels with C/S<0.29 become increasingly silica-rich on leaching but maintain an alkaline pH>9.5 down to at least C/S=0.07 (the lowest ratio reached). For C/S<0.7, chemical modelling and X-ray diffraction data support an explanation of the incongruent dissolution behaviour of the low C/S C–S–H gels based on the congruent dissolution of distinct amorphous silica and tobermorite-like C–S–H phases. Above C/S of 0.7, the dissolution data are well described by an ideal solid solution model for the C–S–H phases. These results are of relevance to the consideration of the disposal of silica-rich vitrified intermediate-level radioactive wastes in cement-based concepts for geological disposal, where maintenance of alkaline pH values forms a key component of the chemical barrier to radionuclide migration. The implications are that the long-term pH buffering capacity provided by cementitious backfill materials would not be significantly affected by interactions with silica-rich wasteforms, which may lower the net C/S ratio of C–S–H phases, due to the natural tendency of these systems to restore congruent dissolution at pH10.8.

&lt;b&gt;Expressões da educação superior nos anos 2000: uma análise discursivo-crítica de documentos do Banco Mundial

Current paper problematizes the construction of World Bank’s guidelines as strategy production consensus on higher education in the first decade of the 2000, taking into consideration the increasingly significant relevance of multilateral organizations as ‘collective intellectual’ (PEREIRA, 2010). The analysis of two main documents, ‘Construir sociedades del conocimiento: nuevos retos para la educación terciária’ (2003) and ‘Learning for All: Investing in People’s Knowledge and Skills to Promote Development’ (2011) are given. The analysis comprises a critical perspective and employs the Critical Discourse Analysis (CDA) as its methodological tools, within the axes: (1) Globalization; (2) Knowledge Society; (3) Eradication of Poverty (4) Public vs. Private relationships; (5) Professional and Technical Education Teaching vs. Education for Technological Innovation. The documents show congruent points in a dual axis, or rather, for the development of state-of-the-art innovation and technology and to comply with the market´s localized demands. Education is consequently required to operate ideologically the contradictions to which capital (through its spokesmen, such as the WB) has no other alternative to offer, providing a solid core of globalization ideology.

Automatic registration of laser point cloud using precisely located sphere targets

Sphere targets are used extensively in terrestrial laser scanning registration; however, in practice, it is still a time-consuming and labor-intensive task. This paper proposes an automatic registration method for laser point clouds based on sphere targets’ detection. First, a modified eight-neighbors check method is applied to mark occluding edge points. Then, for the sphere targets in the raster structure, occluding edge points are clustered, and circle and sphere detections are sequentially implemented in the cluster node and circular area, respectively. The sphere models that pass through multilevel constraints are considered the final results. Next, triangles constructed using three arbitrary noncollinear sphere centers in each scan station are selected as registration primitives and the area and interior angles of each are selected as similarity measures. Finally, the congruent sphere centers between two scan stations are matched in an iterative manner and used to calculate the transformation matrix. The results of experiments in which a lab was scanned from two locations indicate that our method can effectively detect four sphere targets in more than 10 million point clouds within ∼1.5 min, with the largest position error between congruent points <2 mm.

Structure and Properties of Cast Near-Congruent Copper-Manganese Alloys

Microstructure development in the casting of copper-manganese alloys based on the congruent point at 34.6 wt pct Mn and 1146 K (873 °C) has been studied. The alloys were prepared by induction melting of electrolytic Cu and Mn in clay-graphite crucibles in open air. Under conventional casting conditions, the alloys exhibit fine cellular (non-dendritic) solidification morphology with a distinct absence of solidification shrinkage microporosity, and they maintain these attributes over a composition range of approximately 3 wt pct Mn about the congruent point. The high Mn concentration in the alloy admits carbon into solution in the melt, resulting in formation of manganese carbide Mn7C3 particles having two different forms (globular and angular) in the cast microstructure. The Mn carbide was eliminated or controlled to low levels by melting in an alumina or a silicon carbide crucible, or in a clay-graphite crucible at lower temperatures. Microstructure development in casting the alloy was analyzed in terms of the available phase diagrams and thermochemical data. Hardness and tensile testing indicated a potent solid solution strengthening effect of Mn and high ductility in the as-cast condition, with additional hardness (strength) when the alloy contains the Mn carbide phase.

Kirjandusteoreetilise ühendvälja poole

Estonian cultural studies constitute a rich and promising area of research. This area is uniquely positioned to bring together the vast array of methodological approaches that increasingly have come to define our postmodern mindscape. It allows us to more productively unpack salient aspects of national and world literature and to bring into sharper focus the role of the humanities in general. Contemporary research, teaching and supervisory activities in the university environment proceed from an unprecedented openness to multiple differences, older and newer constructions and deconstructions, congruent or incongruent points of view, active merging of many paradigms, intra- or interdisciplinary, and a permanent disposition towards innovation.There are theoretical clusters that focus on the form and structure of a work, combining with linguistic and stylistic, author-centred or reader-centred approaches; intertextual relations; content-driven, i.e., socio-semantic and historical interpretations; and complex combinations of all of these.As a result, contemporary literary research has to integrate an overwhelmingly rich multitude of different productive methods to encompass both levels of mimesis and poiesis, in their respective hermeneutic circles: literary historical, textological, bio-bibliographical and reception studies; close reading, poetic, linguistic, structuralist, semiotic, narratological; intertextual, translation-theoretical; psychoanalytical, cognitivistic; socio-psychological – including gender and memory studies, post-colonialism, new historicism, ecocriticism – as well as intercultural studies; post-structuralist discursive, hermeneutical-phenomenological, mytho-theoretical; analytical philosophical, formal statistical, digital and other current and plausible approaches.Such anthological versatility en gros is necessary as different authors, types of texts, phenomena, traditions and levels can actualise separate points of view, networks and methodologies. Thus, the in-depth study of literatures, avoiding shallow eclecticism and levelling synthesis, should be implemented within a comprehensive, unified meta-multi-theoretical field that integrates diverse paradigms and polylogical perspectives central to the humanities today. The theorisations may be exclusively collateral, have inclusive intersections or be more generally congenial. The use of one cluster does not exclude the consideration of others, even opposing ones. Although the comparative meta-theory, or general poetics, does not aim to erase inevitable and inspiring incoherencies, a synchronisation of meta-languages can often be achieved at the appropriate levels of description, even between analytical and continental language philosophy evident in pragmapoetics (q.v. Merilai 2003, 2007a, b). While the humanities encourage diversity, no scholar, however astute, is expected to have a full command of all relevant discourses within the whole polysystem; hence the need for shared synergies.

Calcium silicate hydrate (C-S-H) gel dissolution and pH buffering in a cementitious near field

AbstractA cementitious backfill has been proposed in many geological disposal concepts for intermediate-level waste and low-level waste in the UK and elsewhere. In this paper, the main features of the chemical evolution of backfill and the associated changes in the near-field pH are illustrated with results from recent work. For example, interaction of the groundwater with calcium silicate hydrate (C-S-H) phases in a backfill is expected to play an important role in the long-term pH-buffering behaviour. Existing experimental data for the dissolution of C-S-H gels are compared with recent experimental results from leach tests on gels of a lower calcium to silicon ratio (C/S) to provide a consistent set of data across the full C/S range. The results confirm that a congruent dissolution point around C/S = 0.8 is approached by leaching from below (i.e. for gels with 0.29 &lt; C/S &lt; 0.8), as well as from above, as reported elsewhere. In addition, a spreadsheet model has been developed to calculate the volume of backfill required at the vault scale to meet specified pH performance criteria. This model includes the major reactions of the backfill with the groundwater, waste encapsulants and waste components. It can also consider the effects of specific waste packages on local pH performance to allow comparison with the vault-scale calculations.