Perfect Glass Research Articles

Direct Single Crystal to Amorphous Transformation and Memory Effect in AlPO4-17.

Pressure induced amorphization provides a distinct route to prepare novel amorphous materials. Single crystals of the porous aluminophosphate AlPO4-17 directly transform to an amorphous state beginning at 0.6 GPa, without fragmentation into polycrystalline material. Apart from a reduction in dimensions, the amorphous material retains the form of the initial single crystal. Remnant crystalline domains in the amorphous material also preserve the initial orientation of the single crystal. X-ray diffraction indicates the compression of the structure around the empty pores in the xy plane and such an amorphization mechanism is consistent with a direct structural relationship between the single crystal and amorphous forms. The collapse of the initial pore volume is almost complete at 2.5 GPa. A memory effect is observed in the amorphous form, which strongly expands on decompression. The present process opens the way for the synthesis of topologically ordered amorphous materials approaching "perfect glasses" with improved mechanical properties.

Dynamic Measure of Hyperuniformity and Nonhyperuniformity in Heterogeneous Media via the Diffusion Spreadability

The recently developed concept of spreadability, $\mathcal{S}(t)$, provides a direct link between time-dependent diffusive transport and the microstructure of two-phase media across length scales. We explicitly compute $\mathcal{S}(t)$ for well-known two-dimensional and three-dimensional model structures, including nonhyperuniform fully penetrable spheres and equilibrium hard spheres, as well as hyperuniform sphere packings derived from perfect glasses, uniformly randomized lattices (URL), disordered stealthy point processes and Bravais lattices. We further confirm that the small-, intermediate- and long-time behaviors of $\mathcal{S}(t)$ sensitively capture the small-, intermediate- and large-scale characteristics of the models. In instances in which the spectral density $\tilde{\chi}_{_V}(\mathbf{k})$ has a power-law form $B|\mathbf{k}|^\alpha$ in the limit $|\mathbf{k}|\rightarrow 0$, the long-time spreadability provides a simple means to extract the value of the coefficients $\alpha$ and $B$ that is robust against noise in $\tilde{\chi}_{_V}(\mathbf{k})$ at small wavenumbers. Interestingly, the excess spreadability $\mathcal{S}(\infty)-\mathcal{S}(t)$ for URL packings has nearly exponential decay at small to intermediate $t$, but transforms to a power-law decay at large $t$. Our study of the aforementioned models enables us to devise an algorithm that accurately extracts large-scale behaviors from diffusion data alone. Lessons learned from such analyses of our models are used to determine accurately the large-scale structural characteristics of a sample Fontainebleau sandstone, which we show is nonhyperuniform. Our study demonstrates the practical applicability of the diffusion spreadability to extract crucial microstructural information from real data across length scales and provides a basis for the inverse design of materials with desirable time-dependent diffusion properties.

Flexural strength improvement for structural glass: a numerical study

Glass is generally known as a fragile material. It is sensible to the cracks created from manufacturing or contact damage. The strength of a perfect glass without crack could reach 10 GPa. By mean of strengthening such as thermal tempering, glass can be safely use for building as architectural elements and very limited to the structural elements. The authors have been developing glass strengthening methods and structural design for large scale glass beam. Some influencing factors are considered: material, premature crack effect, geometry of sample and bolt. The mechanical behaviour of glass is modelled as elastic-plastic material, which show significant results in glass-bolt contact problem. The crack length, size and position provide information of a critical angle that allow to govern the crack effect in the beam connection.

Study the Formation Possibility of some Iron Slag Based Glasses

In an attempt to take advantage of industrial wastes, Iron slag was used to prepare some of glass samples in an attempt to re-use. The following chemical formula has considered in the preparation process. (25 + x) % slag + (75 - x) % (Na₂B₄O₇.10H₂O), where x has varied among different values. The rapid quenching method has used to prepare the glass samples, of thier molten components at 1200°C. When x > 45 had not be obtained any glasses, in the conditions of preparation. Both FTIR and XRD showed that each sample contains x ≤ 45 had formed perfect glass state. Density and molar volume showed that the glass structure became more open with increasing concentration of the slag.

The Perfect Glass Paradigm: Disordered Hyperuniform Glasses Down to Absolute Zero.

Rapid cooling of liquids below a certain temperature range can result in a transition to glassy states. The traditional understanding of glasses includes their thermodynamic metastability with respect to crystals. However, here we present specific examples of interactions that eliminate the possibilities of crystalline and quasicrystalline phases, while creating mechanically stable amorphous glasses down to absolute zero temperature. We show that this can be accomplished by introducing a new ideal state of matter called a “perfect glass”. A perfect glass represents a soft-interaction analog of the maximally random jammed (MRJ) packings of hard particles. These latter states can be regarded as the epitome of a glass since they are out of equilibrium, maximally disordered, hyperuniform, mechanically rigid with infinite bulk and shear moduli, and can never crystallize due to configuration-space trapping. Our model perfect glass utilizes two-, three-, and four-body soft interactions while simultaneously retaining the salient attributes of the MRJ state. These models constitute a theoretical proof of concept for perfect glasses and broaden our fundamental understanding of glass physics. A novel feature of equilibrium systems of identical particles interacting with the perfect-glass potential at positive temperature is that they have a non-relativistic speed of sound that is infinite.

Amorphous Dielectric Thin Films with Extremely Low Mechanical Loss

Abstract The ubiquitous low-energy excitations are one of the universal phenomena of amorphous solids. These excitations dominate the acoustic, dielectric, and thermal properties of structurally disordered solids. One exception has been a type of hydrogenated amorphous silicon (a-Si:H) with 1 at.% H. Using low temperature elastic and thermal measurements of electron-beam evap-orated amorphous silicon (a-Si), we show that TLS can be eliminated in this system as the films become denser and more structurally ordered under certain deposition conditions. Our results demonstrate that TLS are not intrinsic to the glassy state but instead reside in low density regions of the amorphous network. This work obviates the role hydrogen was previously thought to play in removing TLS in a-Si:H and favors an ideal four-fold covalently bonded amorphous structure as the cause for the disappearance of TLS. Our result supports the notion that a-Si can be made a “perfect glass” with “crystal-like” properties, thus offering an encouraging opportunity to use it as a simple crystal dielectric alternative in applications, such as in modern quantum devices where TLS are the source of dissipation, decoherence and 1/f noise.

In search of the perfect glass

The jury's still out on how glasses and other disordered materials form. However, a new framework suggests that we can understand their mechanical properties without this information, by using the physics of jamming.

Thermal collapse of SAPO-34 molecular sieve towards a perfect glass

Controlled collapse of a silicoaluminophosphate molecular sieve CHA-type SAPO-34 by thermal aging was studied in a multi-method approach. Structural changes and the mechanism of order–disorder–order transitions during collapse were followed for varying annealing conditions between 1000 and 1100°C. Collapse of SAPO-34 occurs via the formation of an intermediate amorphous state by the loss of long-range order but preservation to a high degree of short-range order and macroscopic morphology. This intermediate amorphous state with low entropy may be classified as a “perfect glass”. Prolonged aging in the collapse regime results in the precipitation of crystalline AlPO4 while the SiO2 species initially remain in an amorphous phase. Further increasing the aging temperature leads to virtually complete recrystallization and, ultimately, melting.

Comparison of the Rudin and NIBEM Methods for Measuring Foam Stability with a Manual Pour Method to Identify Beer Characteristics That Deliver Consumers Stable Beer Foam

A survey of the preferences of brewing professionals with respect to beer presentation and amount of beer foam was conducted at the ASBC Brewing Summit meeting in Providence, Rhode Island, in 2010. The survey showed that beer presentation in the Samuel Adams Boston Lager Perfect Pint glass was not only aesthetically pleasing but also promoted hop aroma and flavors in particular. Most of the survey participants preferred the presence of lacing on the glass during or after consumption and, on average, considered approx. 20 mm of foam immediately after dispensing into a glass as being optimal. The conventional NIBEM and Rudin methods for foam stability testing were compared with a simple method of manually pouring a beer into a Perfect Pint glass (approx. 35 mm of foam formed) and visually scoring the stability after 5 min to determine the foam stability score (FSS). The NIBEM and Rudin foam stability measures were significantly but relatively poorly correlated (r = 0.371). In part, this relatively poor correlation resulted from a wide range of beer viscosity in the sample set that inordinately influenced the Rudin results. In general, the NIBEM and Rudin foam stability measures were significantly correlated with bitterness, beer-foam-promoting proteins measured as Coomassie blue binding protein assay, beer color, alcohol, CO2 content, and pH, which was broadly consistent with previous studies. Although lipids are widely acknowledged as foam damaging, the measurement of total fatty acids (a lipid proxy) was not well correlated with either of the foam stability analysis methods. The FSS was significantly correlated to and largely predicted by CO2 content and beer-foam-promoting protein levels. These insights are discussed in relation to how brewers could design and consistently provide beers to customers that fulfill their foam quality requirements and expectations.

Arrest of Flow and Emergence of Activated Processes at the Glass Transition of a Suspension of Particles with Hard Spherelike Interactions

By combining aspects of the coherent and self-intermediate scattering functions, we show that the arrest of particle number density fluctuations spreads from the position of the main structure factor peak. We propose that this arrest impairs the system's ability to respond to diffusing momentum currents, leading to an enhanced resistance to flow. From the stretching of the coherent intermediate scattering functions in the glass, we read a manifestation of the undissipated thermal energy-the source of the ergodicity restoring processes that short-circuit the sharp transition to a perfect glass.

Preparation of perfect glasses from zeolites

When glasses are traditionally formed from melts, due to slow crystallization dynamics, the configuration and free volume of the liquid state are frozen in a random structure with high entropy. The amorphous state can also be attained directly from a crystalline solid under pressure. In this case, at a certain rate of change in the pressure, some structural elements can remain ordered; i.e., the amorphous material can retain the crystalline topology. As a result, the amorphous material will have a very low entropy, close to that of the crystal, i.e., will be a “perfect” glass with new physical properties. The method for preparing such a perfect glass from zeolites and its properties are discussed.

Identifying low and high density amorphous phases during zeolite amorphisation using small and wide angle X-ray scattering

In situ experiments following the thermal amorphisation of zeolites reveal massive increases in small angle X-ray scattering (SAXS), persisting well beyond the stage where wide angle X-ray scattering (WAXS) can detect that any crystalline phase is present. This heterogeneity in the amorphised phase is attributed to the transition from a low density amorphous phase (LDA) to a high density amorphous phase (HDA) at the glass transition. The fractions of zeolite, LDA and HDA phases obtained from SAXS analysis are discussed in the context of non-linear changes detected in 29Si solid state NMR during zeolite amorphisation. Whilst the HDA phase is chemically disordered, the LDA phase exhibits much of the Al–Si ordering present in the starting zeolite. These findings are considered in the context of perfect glasses predicted to occur when super strong liquids are supercooled.

Probing the dynamics of instability in zeolitic materials

Zeolites collapse under modest pressure or temperature, their microporous structurestransforming into glasses of conventional density. Using in situ synchrotron radiationdiffraction methods we show how pressure and temperature-induced amorphization areequivalent processes and that these are mirrored by changes in the local structure of chargecompensating cations. Evidence for a low density amorphous phase and a high densityamorphous phase present during zeolite collapse emerges from small angle scatteringexperiments. Combining powder diffraction with increasing temperature or pressure,we find that the thermobaric characteristics for zeolite collapse have negatived T/d P slopes, consistent with increasing density during amorphization. However, this is not confinedto a single melting curve but, instead, the regime extends over a significant region ofT–P space. Moreover, zeolite amorphization involves depressurization and cavitation effectswhich can be used to set empirical boundaries for the stability of the low densityamorphous phase. Within the region of zeolite instability the pressure or temperature ofamorphization is found to be governed by the rate at which the stress is introduced—themore rapid this is, the higher the pressure or temperature the zeolite structure survives to.The temperature dependence of the rate of collapse is Arrhenian, suggesting that the initiallow density amorphous phase has the characteristics of a superstrong liquid incontrast to the fragility of a conventionally melt quenched glass. Possibilities forcreating ‘perfect glasses’ from the collapse of microporous crystals are discussed.

The rheology of collapsing zeolites amorphized by temperature and pressure.

Low-density zeolites collapse to the rigid amorphous state at temperatures that are well below the melting points of crystals of the same composition but of conventional density. Here we show, by using a range of experimental techniques, how the phenomenon of amorphization is time dependent, and how the dynamics of order-disorder transitions in zeolites under temperature and pressure are equivalent. As a result, thermobaric regions of instability can be charted, which are indicative of polyamorphism. Moreover, the boundaries of these zones depend on the rate at which temperature or pressure is ramped. By directly comparing the rheology of collapse with structural relaxation in equivalent melts, we conclude that zeolites amorphize like very strong liquids and, if compression occurs slowly, this is likely to lead to the synthesis of perfect glasses.

`Strong' and `superstrong' liquids, and an approach to the perfect glass state via phase transition

We show first that when the excitations described by the `bond lattice' model, and its `defect' model relatives, are allowed to interact, this simple class of model predicts the possibility of first-order transitions between viscous and fluid liquid states. Looking for support of this prediction, we examine the behavior of a series of `tetrahedral' liquids, all of which are famous for one or another aspect of their behavior. We show that when diffusivity data for these liquids, SiO 2, BeF 2, water, and liquid Si, are plotted on a reduced temperature scale with glass transition temperature as the scaling temperature, a systematic pattern is revealed in which a mild deviation, in the case of BeF 2, from the `strong' extreme of the normal strong/fragile glass-former pattern becomes a (contentious) strong deviation in the case of water and develops finally into the predicted first-order transition deviation in the case of liquid Si. Unfortunately, in the latter two cases, the systematic strengthening of the anomalous character is associated with a decrease in the temperatures of occurrence, such that in each case they fall below the melting point. The corresponding competition with crystallization makes their observation difficult. Our account of the phenomenology, therefore, depends heavily on computer simulation studies, but extensive links to experimental results are given. We relate our findings to the recent observations that the amorphous states of Si and water are unique among glassy systems in showing little or no trace of the very low temperature (glassy state as opposed to liquid state) anomalies formerly considered `ubiquitous' among glassy systems. We interpret this to mean that systems with strong cooperativity in their excitations are able to access the lower minima on their respective configuration space potential energy hypersurfaces and thereby to reach states, which are close to the ideal of the `perfect glass'. In this state the residual entropy is near zero, and the defect-related boson peak and two-level tunneling system excitations are weak or absent. Such systems require unusual routes to access their glassy states and their properties are more closely related to those of crystals than to those of ordinary glasses. A new designation may be required. The range of such systems is large, embracing all the 3:5 and many 2:6 semiconductors.

Water and its anomalies in perspective: tetrahedral liquids with and without liquid–liquid phase transitions

We show how water with its small proton bridge between tetrahedrally coordinated oxygen centers, forms a provocative series with (i) the archetypal glassformer and strong liquid, SiO2, (ii) the analog ionic compound BeF2 in which the Be ions are bridged by fluoride ions, and (iii) elemental Si with no bridge at all. As the size of the bridging unit decreases from the polarizable oxide of silica through the unpolarizable fluoride of BeF2, the tiny proton of water, and finally vanishes at silicon, the constraints on the network tighten. As the constraints become more severe, the departures from simple activated diffusion behavior of SiO2 during heating of the amorphous phase at ambient pressure, become more pronounced. In the case of Si, the extreme of a first-order transition from strong to extremely fragile liquid state is manifested in the supercooled regime. With water the behavior is intermediate. In both cases the anomalous regime is located in the supercooled state which greatly complicates its investigation and leads to much controversy. In the case of BeF2, for which the exceptional viscosity behavior can now be understood, new MD results show that a weakened form of the anomalies exists. The weakened anomaly should be observable in detail in experimentally accessible ambient pressure conditions, because now it occurs in the thermodynamically stable domain, at temperatures which lie above those studied to date. The observable anomalies should include not only a density maximum but also a density minimum, and a smeared lambda type heat capacity anomaly. In view of the phase diagrams deduced for various water models, our observations suggest that the second critical point scenario proposed for water, if correct, might be observable under thermodynamically stable conditions at high pressures in the case of BeF2. In the cases of water and Si, in which the interaction potentials cause the critical point to lie at relatively low or negative pressures, respectively, the glassy state proves to have unusual properties intermediate between those of normal glasses and crystals. It is suggested that such glasses, which will include many Si analogs such as Ge, InSb, etc, might constitute a distinct class of amorphous material with the attributes (low residual entropy, etc.) of the hypothetical perfect glass state.

The Fear of the Father: Dombey and Daughter

Research Article| March 01 1985 The Fear of the Father: Dombey and Daughter Lynda Zwinger Lynda Zwinger Search for other works by this author on: This Site PubMed Google Scholar Nineteenth-Century Fiction (1985) 39 (4): 420–440. https://doi.org/10.2307/3044713 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Lynda Zwinger; The Fear of the Father: Dombey and Daughter. Nineteenth-Century Fiction 1 March 1985; 39 (4): 420–440. doi: https://doi.org/10.2307/3044713 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu nav search search input Search input auto suggest search filter All ContentNineteenth-Century Literature Search This content is only available via PDF. Copyright 1985 The Regents of the University of California Article PDF first page preview Close Modal You do not currently have access to this content.

Theory of glasses

It is argued that is possible to define a ‘perfect glass’ which is both preparable experimentally and understandable theoretically. Some basic conditions and statistical thermodynamics are derived. Polymerized glasses are complex substances but it is argued that progress may be possible by considering them to have short range properties, and long range properties. Examples are given of models of glasses with such properties and their behaviour is shown to be amenable to theory.