bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Ex-SituReactor with Anaerobic Specimen Transfer Capabilities for TEM Studies of Reactive (Catalyst) Specimens
Authors: Allard L F , Ailey K S , Datye A K , Bigelow W C 
Published: July 2020

Abstract
The optimization of currently available catalysts and the development of new ones requires a detailed understanding of the effects of both microstructure and composition on their function. Previous work has demonstrated that information at the atomic-scale on heterogeneous catalysts can be derived using high resolution transmission electron microscopy (TEM). Under favorable conditions, the morphology of heavy metal catalytic particles can be related to catalytic activity. It has been shown that preoxidation can disrupt the surface of small metal particles causing altered activity and selectivity in reactions such as alkane hydrogenolysis. Metals such as Pt, Rh, or Ru are noble and pick up no more than a monolayer of oxygen when exposed to air during sample preparation for microscopy. This oxygen monolayer is not imaged in the microscope, most likely because the oxygen desorbs during exposure to the high energy electron beam. However, when metals such as Fe, Co, Ni, Pd or Cu are exposed to air, there is a corrosive interaction that alters particle structure quite dramatically.
In-Situ Observations of the Effect of Electron Irradiation on the Defect Microstructure of Alumina
Authors: Chen S-J , Dahmen U , Howitt DG 
Published: July 2020

Abstract
The interaction of radiation produced point defects with a dislocation microstructure at high temperature is of considerable interest and careful high voltage microscopy experiments can provide valuable insight into the mechanisms. Veyssière and Westmacott carried out in-situ experiments monitoring the partial dislocation climbs in Ni3Al induced by thermal vacancies as well as by Frenkel pairs produced during irradiation.1 We report here the results of some preliminary experiments we performed on alumina (A12O3) single crystals with high dislocation densities to study the modification of the microstructure by electron irradiation at high temperature.
The dislocation microstructures were produced by shock wave deformation using a high-velocity impact technique. The technique is capable of producing a very high density of defects consisting primarily of basal twins, and slips on the basal, pyramidal and rhombohedral planes in alumina. The dislocations are all of glide type, mostly forming shear bands. A typical microstructure prior to irradiation is shown in figure la.
The Observation of Hierarchical Structures in Biopolymer Phase Separation : Novel ESEM Contrast Mechanisms
Authors: Bache C , Anderson V J , Jones R A L , Donald A M 
Published: July 2020

Abstract
Gelatin and dextran are two water soluble biopolymers of considerable importance in the food industry, both separately and in combination. A solution of gelatin and dextran (∼ 10% total polymer concentration) forms a single phase at high temperatures, and on cooling undergoes phase separation, which may occur simultaneously with the gelation of the gelatin. The exact phase distribution in the final microstructure is dependent on the initial polymer concentrations, and the relative rates of gelation and phase separation. Much work has been done on such systems in the past, using a variety of techniques. Most recently, optical microscopy and small angle light scattering (SALS) have been used to characterise the structure of this particular system, especially for systems at the critical concentration. However due to the constraints imposed by sample preparation, very little Scanning Electron Microscopy (SEM) has been carried out on such systems - freeze drying and the problems of obtaining contrast between the phases without staining make such experiments difficult and sometimes inconclusive.
Effects of Space Charge on ESEM Gas Amplification
Authors: Thiel BL , Hussein-Ismail MR , Donald AM 
Published: July 2020

Abstract
We have performed a theoretical investigation of the effects of space charges in the Environmental SEM (ESEM). The ElectroScan ESEM uses an electrostatic field to cause gas cascade amplification of secondary electron signals. Previous theoretical descriptions of the gas cascade process in the ESEM have assumed that distortion of the electric field due to space charges can be neglected. This assumption has now been tested and shown to be valid.
In the ElectroScan ESEM, a positively biased detector is located above the sample, creating an electric field on the order of 105 V/m between the detector and sample surface. Secondary electrons leaving the sample are cascaded though the gas, amplifying the signal and creating positive ions. Because the electrons move very quickly through the gas, they do not accumulate in the specimen-to-detector gap. However, the velocity of the positive ions is limited by diffusion.
ESEM and Video Microscopy Studies in Stone Conservation
Authors: Doehne Eric 
Published: July 2020

Abstract
Observation of stone deterioration using in situ,time-lapse microscopy techniques has revealed previously undescribed material behaviors that help to explain the destructive effects of several important processes in wall paintings, historic structures and monuments. It has long been acknowledged that cyclic stresses imparted by humidity changes, wet-dry cycling, and the crystallization and hydration of soluble salts, are important agents in the deterioration of these porous structures. The crystallization of salts is a particularly serious conservation problem (Arnold, 1975). Over time, cyclic salt crystallization results in the physical breakdown of the material (Goudie, 1993). Objects affected by such processes are often difficult to conserve since they are weak to begin with and the presence of salt inhibits the curing of some common conservation materials (Price and Kumar, 1994).
Sodium sulfate is one of the most damaging of salts, apparently because it expands during the transition from the anhydrous phase (Na2SO4; thenardite) to the decahydrate form (Na2SO4•l0H2O; mirabilite).
solid-state reactions in the presence of an electric field
Authors: Johnson Matthew T , Carter CBarry 
Published: July 2020

Abstract
It is well known that diffusion in ionic materials occurs primarily by the movement of charged species. Therefore, an electric field should provide a very powerful driving force for mass transport. In the present study, solid-state reactions, in the presence of an electric field, have been carried out between thin films of In2O3 and bulk monocrystalline MgO ﹛001﹜. In solid-state reactions of this type, reaction rates and interfacial stability are affected by the transport properties of the reacting ions. by applying an electric field across the sample, at elevated temperatures, the reaction rates and interfaces are affected as a result of ionic conductivity. Through the use of electron microscopy techniques the reaction kinetics and interface morphology have been investigated, in this spinel forming system, to gain a better understanding of the influence of an electric field on interface morphology and solid-state reactions.
The reaction couples used in this study were produced by means of pulsed-laser deposition (PLD).
Crystallization of Cordierite Glass Ceramics for Joining SiC: Must Phase Separation Via Spinodal Decomposition Precede Nucleation?
Authors: MoberlyChan Warren J , Perham T J , DeJonghe L C 
Published: July 2020

Abstract
The crystallization of glass ceramics provides processing advantages for difficult shapes. Machining and sintering are limited to produce complex parts; similarly (superplastic) forming is limited to special ceramics. In theory, however, a liquid (or glass) may be simply poured into any shape, and then crystallized (or partially crystallized) to provide a strong, tough ceramic. In this work, a thin layer of glass ceramic, cordierite (2MgO.2Al2O3.5SiO2), joins SiC [1]. Tailoring secondary phases and percent crystallization provide flexible control of the coefficient of thermal expansion to minimize strain mismatches between the joint components.
Three processing steps are involved in crystallization of glass ceramics: first a fast quench produces the initial glass; the second step is a lower temperature “nucleation” anneal, where phase separation and/or precursors and/or the final structure is nucleated and ideally as a fine dispersion; the third step is the higher temperature “crystallization” anneal, where renucleation and/or growth develops a homogeneous (ideally fine grained) final crystalline product [2, 3].
Structural Characterization and Modeling of the Aluminum (111) / Aluminum Oxide (0001) Interface
Authors: Medlin DL , Smugeresky JE , McCarty KF , Tepesch PD , Quong AA , Baskes MI 
Published: July 2020

Abstract
We are investigating the structure of the Al (11l)/Al2O3 (0001) interface. Interfaces for this study were produced by epitaxial thin film deposition of aluminum metal onto (0001) oriented single crystal α-Al2O3. The majority of grains within the films are oriented with:
(0001)Al2O3 || (lll)Al [10Î0]Al2O3 || [ī10]Al
This relationship results in a matching of the close-packed planes and directions of the aluminum metal with those of the oxygen ion sub-lattice in the Al2O3and allows for two variants related by 180° rotations about the aluminum [111] axis. A diffraction pattern showing these two variants is given in Figure 1. Figure 2 shows a HRTEM image of the heteroepitaxial aluminum/Al2O3 interface. The Al2O3 substrate and aluminum overlayer are imaged along the [10Ï0]Al2O3 and [ī10]A1 zones. Over the width of the image, the interface is sharp to within a few atomic layers.
The calculated lattice misfit for the Al/Al2O3 system, taken as the difference between the translation vectors of a/3[10ī0]Al2O3 (2.7447 Å) and a/2[ī10]AI (2.8634 Å), is 4.3%. A fundamental issue is the manner in which this misfit is accommodated.
The Structure of Twin Boundaries in Cluster Compounds: Potassium Barium Oxomolybdate
Authors: Ramlau R , McCarley R E , Simon A 
Published: July 2020

Abstract
K0.19Ba3.18Mo22O34is a representative of the quaternary reduced molybdenum oxides in the series Mn±δMo4n+2O6n+4. These compounds contain condensed clusters Mo4n+2O8n+10 with a core of n trans edge-sharing molybdenum octahedra. The general concept of cluster condensation is discussed elsewhere. In the case of n being finite the clusters are designated as ‘oligomeric’. The individual clusters are interconnected via common oxygen atoms and arranged in layers. For the title compound with n = 5, the clusters consist of 5 molybdenum octahedra and are accompanied by 4 counter-cations (potassium and barium).
The real structure of K0.19Ba3.81Mo22O34 has been recently studied with a Philips CM30/ST (Cs = 1.15 mm) by HREM, SAED, and EDXS. Besides chemical intergrowth of oligomeric clusters with n = 2—18 in the matrix consisting of pentameric clusters, polytypism was observed. Three ordered polytypes (modifications) were found, whereas only one of them, lM (Ramsdell notation), was detected and analyzed with x-ray methods.
Microstructure Characterization of Ni-V Splat Quenched Foils
Authors: Sieber H , Allen DR , Perepezko J 
Published: July 2020

Abstract
Although the thickness of splat quenched (SQ) foils is normally less then 100 μm the solidified microstructure is usually not homogenous, but rather is determined by a cooling rate dependent nucleation and growth behavior of the different phases. The cooling rate and thus the microstructure changes significantly with distance from the edge to the middle of the SQ foils. Rapidly quenched nickel-vanadium (Ni-V) foils consist of three phases formed during solidification, a Ni-fcc, a V-bcc and a intermetallic σ phase [1-3]. To interpret the microstructure evolution in detail, a special TEM cross section sample preparation was applied. The SQ foil was ground to 30 μm, glued on a copper grid and ion-milled parallel to the foils (Fig.1a). In Ni-49V SQ foils seven typical microstructure regions (see Fig. 1 b) could be identified and were analyzed in detail by TEM investigations in plan view and cross section geometries. Furthermore, three solidification pathways were identified.
Microstructural Characterization of α2 + γ Titanium Aluminides
Authors: Larson D J , Miller M K 
Published: July 2020

Abstract
Two-phase α2+γ TiAl alloys with microalloying additions, Fig. 1, are of interest due to the high strength-to-weight ratio they can provide in automotive and aircraft applications. In boron-doped α2+γTiAl containing Cr, Nb, and W, the B levels were found to be significantly depleted below the nominal alloy content in both the α2 andγ phases. The boron solubilities in the γ and α2 phases were 0.011 ± 0.005 at. % B and 0.003 ± 0.005 at. % B, respectively in Ti-47% Al-2% Cr-1.8% Nb-0.2% W-0.15 % B that was aged for 2 h at 900°C (base alloy). The majority of the B was in a variety of borides including TiB, TiB2 and a Cr-enriched (Ti,Cr)2B precipitate. With the exception of the smaller (&lt; 50 nm thick) Cr-enriched (Ti,Cr)2B precipitates, Fig. 2, most of the borides were larger than ∼100 nm. A significant proportion of the microalloying additions is in these borides, Table 1.
Study of Precipitates Morphology and Composition Evolution using Scanning Electron Microscopy (SEM) and Energy Dispersive X Ray Spectroscopy (eds) in as Cast, Forged and Heat Treated Complex Aluminium Bronzes
Authors: de Arenas I B , Centeno L , Arenas F 
Published: July 2020

Abstract
The Aluminium Bronzes are successfully used in heat exchanger tubes, particularly in chemical and oil industries, where they are subjected to sligthly acid conditions or higher temperatures and stresses than other copper alloys allow. For a maximun resistance to corrosion an understanding of the effects of composition and metallurgical structure is desirable. This work study the different precipitates appearing in ASTM B148-C95800 complex Al bronze alloy, due to the structural development in as cast,forged and heat treated conditions, the presence of Fe and Ni as additions enhance the presence of many different precipitates all over the structure, changing the corrosion resistance and mechanical properties.
In this type of alloy the non-stoichiometric β phase breaks down progresively during cooling from high temperatures: 750° - 950°C to give a finely divided iron - nickel - aluminium “kappa” (κ) phase in a copper rich (α) matrix. Such α + κ alloys generally can contains small quantity of β and none γ2 (deleterious to all properties), showing excellent corrosion resistance combined with high tensile strength.
Interfacial Reaction Between Tin-Zinc Based Solders and Copper
Authors: Ghosh G , Fine M E 
Published: July 2020

Abstract
Due to the interfacial reaction between the solder and substrate, either during manufacturing or in service, the solder joints may contain one or more intermetallic layers at the interface. While such intermetallic layers may provide strong bonding, they may also be responsible for problems associated with solderability and reliability of joints. Certain physical and mechanical properties of the intermetallic may determine the integrity and reliability of solder assembly. So far detailed analysis, modelling, and testing of simulated and actual joints have been performed with Pb-Sn solders. However, in view of the increasing environmental and legislative concerns, lead-free solders are currently being developed and designed for microelectronics applications. As the solder joints in high-performance electronic circuits are expected to carry increasing mechanical, electrical and thermal burdens, it is essential to address the technological and reliability issues for lead-free solders. Among the lead-free solders, tin-zinc based alloys can be designed to achieve melting and solidification behavior similar to those of lead-tin eutectic or near eutectic alloys.
Synthesis, Properties and Characterization of Red Phosphor Particles of Y2O3:Eu
Authors: Jiang Y D , Wang Z L , Zhang F , Paris H G , Summers C J 
Published: July 2020

Abstract
High resolution and high efficiency planar display, one of the national priorities for advanced technologies and commercial applications, require highly efficient phosphor materials with crystalline monodispersive fine particles [1,2]. Europium oxide activated yttrium oxide (Y2O3:Eu) is a potential red-emission phosphor powders to be used in high efficiency electroluminescence and field emission displays. In this paper, a novel hydrolysis technique is employed to prepare phosphor particles of Y2O3: Eu, and the structure characterization is reported.
In this synthesis technique, urea reacts with water to release OH−, cations of Y3+ and Eu3+ combine with OH− to form (Y1−xEux)(OH)3 precipitates. Y2O3 particles doped with Eu are formed after the precipitates being fired at a given temperature [3]. The particles prepared by this method are nearly spherical, and have an average diameter of ∼200 nm (Fig. 1). The distribution of particle sizes is narrow, and almost no agglomeration among particles is observed. The particle sizes remain approximately the same before (Fig. 1a) and after (Fig. 1b) being fired at 1200°C.
Analytical TEM and EPMA Study of Decomposition Reactions in an Oxygen-Separation Membrane Material
Authors: Christoffersen R , Kim S , Yang YL , Jacobson AJ 
Published: July 2020

Abstract
Mixed-conducting oxides with appropriate values of electronic and ionic conductivity have the potential to be used as ceramic “membranes” for the separation of oxygen from other gases. The separation is based on oxygen transport from an O2-rich, and hence oxidizing, gas reservoir on one side of the membrane to an O2-lean, and hence reducing, take-up reservoir on the membrane's other side. The oxide Sr(Co1-xFex)O3-δ (SCFO), which has a cubic perovskite structure, is one such potential membrane material. Although the permeation flux of oxygen through SCFO membranes has been mea-sured, the microstructural evolution of SCFO membranes during permeation has been little studied in comparison to other potential membrane oxides. Several of these other systems do show segregation and/or decomposition phenomena that potentially may affect membrane properties. Here we report preliminary results of a systematic microanalytical study of SCFO membranes using scanning electron microscopy and microanalysis in an electron probe microanalyzer (EPMA), as well as transmission electron microscopy in an analytical TEM.
HVEM-Tandem and Eels Study of Radiation Damage in Zirconolite
Authors: Smith Katherine L , Zaluzec Nestor J , Lumpkin Gregory R 
Published: July 2020

Abstract
Zirconolite (CaZrTi2O7) is the major host phase for actinides in Synroc, a promising waste form for the immobilisation of high-level radioactive waste. The effect of radiation damage on the structure and durability of zirconolite are important to predictive modelling of zirconolite's behaviour in the repository environment and risk assessment.
In this study, radiation damage effects in zirconolite were investigated by irradiating samples with 1.5 MeV Kr+ ions using the HVEM-Tandem at Argonne National Laboratory (ANL) and energy loss electron spectroscopy (EELS). The HVEM-Tandem consists of a modified AEI high votage transmission electron microscope interfaced to to a 2 MV tandem ion accelerator. EELS spectra were collected using a Philips 420 TEM, operated at 120 kV, fitted with a Gatan Model 607 Serial EELS. EELS data were recorded at resolutions of ˜1.0 eV and at a dispersion of about ˜0.25 eV.
Selected area diffraction patterns (SADs) of individual grains of various zirconolites were monitored as a function of dose to establish the critical dose for aniorphisation (Dc).
Interfacial Segregation in Oxide Scales on Nicrai-Based Alloys
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Prüβner K , Alexander K B , Pint B A , Tortorelli P F , Wright I G 
Published: July 2020

Abstract
Previous studies addressing the segregation of reactive elements in protective oxide scales and their beneficial effect on scale adhesion have primarily concentrated on primary alumina-formers (e.g. β-NiAl + FeCrAl).In our study the oxidation behaviour of three NiCrAl alloys, which form complex scales was studied in air at 1423 K and at 1473 K, both in isothermal (100 h) and in cyclic oxidation (100 x lh). The composition (in at.-%) of these alloys is the following: General Electric alloy René N5 (64.9 Ni, 7.8 Cr, 13.9 Al, 0.1 Fe, 2.1 Ta, 0.05 Hf, 1.6 W, 1.0 Re, 0.15 Si, 7.3 Co, 0.9 Mo, 0.003 Y, 0.003 Zr, 4 ppm S, 0.25 C), Ni-7Cr-6.5Al+Y (80.1 Ni, 7.2 Cr, 12.5 Al, 0.01 Fe, 0.14 Si, 0.012 Y, 18 ppm S, 0.05 C) and Ni-10Cr-10Al+Y (71.2 Ni, 9.9 Cr, 18.8 Al, 0.01 Fe, 0.02 Si, 0.041 Y, 16 ppm S, 0.04 C).
Characterization of Tubercles in Cast Iron Water Distribution Pipes Using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS)
Authors: Bailey GW , Dimlich RVW , Alexander KB , McCarthy JJ , Pretlow TP , Sarin P , Kriven WM , Snoeyink VL 
Published: July 2020

Abstract
Corrosion of cast iron (C.I.) pipe often results in the formation of “tubercles” on the inner surface of the pipe. Tubercles are layered deposits formed by the stacking of several layers of corrosion products one on top of the other (Fig.l). Tubercles not only increase the amount of energy required for transport of water but are also considered the main source of turbidity in potable water. Their chemical and physical characteristics are important factors which affect the release of iron into the bulk water.
Tubercles are extremely complex systems. They may be highly crystalline in nature, with iron occurring in chemical structures, such as siderite (FeCO3), goethite (α-FeOOH), magnetite (Fe3O4) and lepidocrocite (γ-FeOOH) or they may be highly amorphous. Tubercles vary in height from a few millimeters to a few centimeters. They exhibit distinct layers which are formed over varying periods of time ranging from a few months to a century.
The Birefringence of thin filaments measured with the Pol-Scope
Authors: Oldenbourg R , Salmon Edward D , Tran Phong T 
Published: July 2020

Abstract
The living cell is criss-crossed by dense networks of filaments providing mechanic stability, site directed molecular transport and support of other vital cell functions. With the polarized light microscope we can observe the birefringence associated with thin filaments or partially oriented filament networks and measure the birefringence directly in the living cell (Fig. 1). Filament birefringence is a consequence of the elongated shape of the molecules and occurs naturally without the need to stain or label them, as is necessary in fluorescence imaging.
We have measured the birefringence of microtubules and axoneme filaments using the new polarized light microscope (Pol-Scope).The design of the Pol-Scope is based on the traditional polarized light microscope in which the crystal compensator is replaced by a universal compensator made from two liquid crystal variable retarders. Electronic image acquisition in the Pol-Scope is synchronized to liquid crystal settings to capture a sequence of four images with circular and elliptical polarization.