Inversion of drilling-induced tensile fracture data obtained from a single inclined borehole

We investigate the feasibility of estimating an in situ three-dimensional stress field by using data of drilling-induced tensile fractures (DTFs) observed in a single inclined borehole. The principal assumptions in this investigation are that the rock is isotropic, homogeneous and elastic. A DTF is a longitudinal crack consisting of many small parallel cracks which are oblique to the borehole axis. A DTF is characterized by its circumferential position (θ_mD) along the borehole surface and the inclination (γ_m) of the small cracks with respect to the borehole axis. We show how it is possible to estimate the three-dimensional stress field by using the variation of θ_mD and γ_m with respect to borehole orientation (i.e. azimuth and inclination of a borehole). Based on the variation of θ_mD and γ_m as functions of borehole orientation which changes with depth, an inverse problem is formulated to estimate the three-dimensional stress field. Tests with synthetic data sets (θ_mD and γ_m) show that it is feasible to estimate the three-dimensional stress field and that the statistical approach is appropriate for the inversion practically. Finally, we discuss a DTF data set (θ_mD and γ_m) measured in a real borehole in the northern area of Japan Main Island and apply the inversion technique to estimate the stress field.     

Alloying behavior of Co3Ti

The alloying (substitution) behavior of Ll₂-type Co₃Ti({fx1433-01}) compound was investigated at an isothermal section of 1323 K by the observation of the direction of solubility lobe of Ll₂ phase. The solubility lobes of additions of V, Ta, Cr, W, and Al indicated that they substitute for Ti site, those of Ni and Cu for Co site, and that of Fe for both sites. However, the preferable substitution natures for additions of Zr, Hf, Nb, Mn, and Si, and of Mo and Ge were not determined because of the small solubility limit, and because of no preferable solubility lobe, respectively. The substitution behavior and solubility limit obtained in the ternary Co₃Ti compound were evaluated with the thermo-dynamic concept. The Research Institute for Iron, Steel and Other Metals The Research Institute for Iron, Steel and Other Metals     

Positive‐tone photoresist consisting of a multifunctional acrylate resin that can be patterned after photo‐crosslinking

A multifunctional acrylate resin having a tertiary ester structure is synthesized using a thiol‐acrylate Michael addition click reaction. By loading both a photo radical initiator and a photo acid generator into this resin, a positive‐tone photoresist, that can be patterned after photocrosslinking (PPaP), is formulated. After the thin film is irradiated with 365 nm light, radical crosslinking proceeds and a solvent resistant “frozen” film can be obtained. The frozen film works as a positive‐tone photoresist. When the frozen PPaP is irradiated with light containing a wavelength much shorter than 300 nm, the ester structure of the exposed region is decomposed by photo‐chemically generated acid and dissolved in an alkaline solution. Furthermore, a photochemical pattern transfer is achieved using the material. By performing the photo exposure on conventional photoresist patterns on the frozen PPaP underlayer, the photoresist patterns are successfully transferred to the underlayer. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45871.     

Three-dimensional numerical analysis of mixed ionic and electronic conducting cathode reconstructed by focused ion beam scanning electron microscope

Three-dimensional microstructure of mixed ionic and electronic conducting cathode, La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ (LSCF6428), is obtained by a dual-beam focused ion beam-scanning electron microscope, and its overpotential is predicted by the lattice Boltzmann method. Gaseous, ionic and electronic transport equations coupled with electrochemical reaction at the gas/solid interface in the three-dimensional microstructure are solved with an assumption of local equilibrium in the solid oxide. The gas transport is modeled by the dusty gas model. The numerical simulation is conducted under the current density conditions of 0.01, 0.05, 0.1 and 0.2 A/cm². Predicted cathode overpotentials agreed well with the experimental results. However, predicted overpotential was very large at O₂ = 20%, T = 973 K and i = 0.2 A/cm² case due to the decline of ionic conductivity at low oxygen partial pressure. Three-dimensional chemical potential and current vector distributions inside LSCF microstructure are presented. Ionic and electronic current stream lines are uniform and smooth, which indicates good ionic and electronic conductions as well as wide electrochemically active areas inside the LSCF microstructure. Present method will be an effective tool for investigating local oxygen potential field which affects local reactions, diffusions and physical properties of the MIEC cathodes.     

Europium-binding abilities of dissolved humic substances isolated from deep groundwater in Horonobe area,Hokkaido, Japan

The binding of europium to dissolved humic substances (HSs), isolated from deep groundwater in the Horonobe area, Hokkaido, Japan, was evaluated by means of a three-dimensional fluorescence quenching technique. The Ryan and Weber model, extended by the charge neutralization model, was applied to the fluorescence quenching profiles to evaluate the conditional binding constants (K) at pH 5.0 and an ionic strength of 0.1. The K values for fulvic (FA) and humic acids (HA) in the Horonobe groundwater were comparable with each other regardless of the position of the fluorescence peaks. As compared with HSs from Lake Biwa, Aldrich, and Dando soil, the K values of the Horonobe groundwater HSs were the smallest, indicating that the Horonobe groundwater HSs have a lower affinity for the binding of europium compared to the HSs from surface environments. In addition, the results of the Aldrich-based comparison indicate that the Horonobe groundwater HSs have a lower binding affinity for trivalent lanthanides/actinides compared with other groundwater HSs obtained from different aquifer. These findings demonstrate that the characteristics and origin of deep groundwater HSs needs to be taken into consideration assessing the effects of HSs on the speciation of radionuclides in deep groundwater in geological disposal systems.     

Thinned wafer multi-stack 3DI technology

Wafer scale 3DI technology, so-called wafer-on-a-wafer (WOW), characterized by thinned-wafer stacking and Cu multi-level interconnects, has been developed, and revealed that seven-level multi-wafer stacking is possible. The WOW process differs from the chip-on-a-chip and chip-on-a-wafer processes and can be used for wafer-scale bulk processes, enabling manufacturing from transistor to 3D stacking using wafers. Wafers are thinned down to 20-μm and bonded to the base wafer following back-to-face stacking. Through-silicon-via (TSV) holes with a diameter of 30 μm are formed and etched-off until the lower electrode of Au which is patterned on the underneath wafer. Titanium (Ti) and titanium-nitride (TiN) are formed on a TSV hole as a barrier metal and electrode for the electrochemically plated Cu (ECP-Cu). After ECP-Cu deposition, surface planarization is performed using Surface Planer™. Those wafers are used as a base wafer and multi-stacking is carried out repeatedly. The vertical connection between Cu of TSV and Au is therefore connected with a self-aligned contact and without a bump electrode. The electrical properties of the 242-chain contacts within the wafer were measured and no open failure was found. Adopting the thinned substrates eliminates deep silicon etching, and TSV filling which take a long process time, and reduces the residual stress on the Cu plug. Wafers can be stacked as much as possible in accordance with the degree of integration, and this is expected to be a low-cost and high-integration technology for post-scaling.     

Phase field and room-temperature mechanical properties of the C15 laves phase in the Zr-Ta-Cr alloy system

The phase field of the C15 Laves phase in the Zr-Ta-Cr alloy system at 1273 K exhibited a continuous solid solution along the ZrCr₂-TaCr₂ pseudobinary line and also a broad off-stoichiometric range on the (Zr,Ta)-rich side. The defect structures in the C15 Laves phase were evaluated by lattice parameter and density measurements. The room-temperature fracture toughness was assessed by Vickers indentation testing. Alloying, off-stoichiometry, and the related defect structures were shown to be beneficial for improving the room-temperature deformability of the C15 Laves phase in the Zr-Ta-Cr alloy system. The results are discussed in terms of the constituent atomic sizes on the most closely packed planes in the C15 Laves phase where shear deformation takes place. This article is based on a presentation made in the symposium entitled “Beyond Nickel-Base Superalloys,” which took place March 14–18, 2004, at the TMS Spring meeting in Charlotte, NC, under the auspices of the SMD-Corrosion and Environmental Effects Committee, the SMD-High Temperature Alloys Committee, the SMD-Mechanical Behavior of Materials Committee, and the SMD-Refractory Metals Committee.     

Defect structures and room-temperature mechanical properties of C15 laves phases in Zr-Nb-Cr and Zr-Hf-Cr alloy systems

The effect of composition on the pseudobinary ZrCr₂-NbCr₂ and ZrCr₂-HfCr₂ C15 Laves phase alloys were investigated, focusing upon defect structures and room-temperature fracture toughness. The defect structures were evaluated by lattice parameter and density measurement. The room-temperature fracture toughness was assessed by Vickers indentation test. Alloying, off-stoichiometry, and related defect structures were shown to be generally beneficial for improving the room-temperature fracture toughness of the C15 Laves phases. The results were discussed, based on the local atomic size argument on the most closely packed planes in the C15 Laves phases where shear deformation takes place.     

Inhibitors of acyl-CoA:cholesterol O-acyltransferase. 3. Discovery of a novel series of N-alkyl-N-[(fluorophenoxy)benzyl]-N'-arylureas with weak toxicological effects on adrenal glands

A series of N-alkyl-N-[(fluorophenoxy)benzyl]-N'-arylureas were prepared and evaluated for their ability to inhibit intestinal acyl-CoA:cholesterol O-acyltransferase and to inhibit accumulation of cholesteryl esters in macrophages in vitro. In vivo hypocholesterolemic activity was assessed in cholesterol-fed rats by oral administration as a dietary admixture and/or by gavage in a PEG400 vehicle. Modification of the alkyl substituent on the N'-aryl moiety and on the urea nitrogen significantly influenced macrophage assay in vitro. Toxicological study revealed a distinct relationship between macrophage assay and the toxicity observed in adrenal glands of rabbits treated with representatives of this series of compounds. Investigations utilizing the macrophage assay as an indicator for adrenal toxicity led to the identification of compounds 1g (FR190809) and 1k (FR186485, or FR195249 as its hydrochloride salt) as potent, nonadrenotoxic, orally efficacious ACAT inhibitors irrespective of the administration method.     

Compression fatigue failure of CFRP laminates with impact damage

The objective of this study is to investigate failure mechanisms of impact-damaged CFRP laminates subjected to compression fatigue. Two kinds of composite materials, UT500/Epoxy and AS4/PEEK, were used to examine the dependence of failure behavior on the material properties such as interlaminar toughness. Impact-induced delaminations in the UT500/Epoxy specimen were considerably larger than those in the AS4/PEEK specimen. The S–N curves for the UT500/Epoxy specimens with impact damage exhibited a similar tendency to those without impact. The impact-induced delamination in the UT500/Epoxy specimen grew widthwise to the free edge on the rear side of the specimen during the fatigue test. On the other hand, the AS4/PEEK specimens without impact exhibited a more steeply declining S–N curve than those with impact damage. The delaminations in the impacted AS4/PEEK specimen did not reach the free edge before the fatigue fracture.