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Accumulation and concentration of debris in deep hole electrical discharge machining (EDM) significantly hinder its machining efficiency and accuracy. It is believed that the movement of bubbles associated with the discharge gap flow field play a pivotal role in debris removal and influence the discharge conditions. Ultrasonic vibration (USV) of the electrode is thought to be an effective method for improving EDM-generated bubbles and debris exclusion. In this study, we first elucidated the behavior of bubbles during EDM of holes with varying aspect ratios. Subsequently, USV was introduced to EDM. The behavior of dielectric fluid flow under the influence of ultrasonic vibration was analyzed using computational fluid dynamics (CFD), which revealed time-varying changes in discharge gap flow pressure and velocity. The velocity of the dielectric flow field near the electrode's side face was found to reach a maximum of approximately 15.2 m/s, greatly facilitating debris removal. High-speed camera observations revealed that bubbles were dispersed within the side gap, with most of them adhering to the electrode's wall. Furthermore, the bubbles exhibited a tendency to continuously break up and coalesce near the hole's outlet before escaping in the USV-assisted EDM. These observed characteristics of bubble behavior under the influence of USV are expected to significantly enhance debris removal and promote efficient dielectric exchange. [ABSTRACT FROM AUTHOR]

This paper deals with a non-destructive analysis of residual stress through the visualization of deformation behaviors induced by a local spot heating. Deformation was applied to the surface of an aluminum alloy with an infrared spot laser. The heating process is non-contact, and the applied strain is reversible in the range of room temperature to approximately +10 °C. The specimen was initially pulled up to elastic tensile stress using a tensile test machine under the assumption that the material was subject to the tensile residual stress. The relaxation behaviors of the applied strain under tensile stress conditions were evaluated using contact and non-contact methods, i.e., two strain gauges (the contact method) and a two-dimensional electronic speckle pattern interferometer (non-contact method). The results are discussed based on the stress dependencies of the thermal expansion coefficient and the elasticity of the materials. [ABSTRACT FROM AUTHOR]

This study is aimed at developing an anisotropic elastoplastic constitutive model for geomaterials at finite strain and its stress calculation algorithm based on the fully implicit return‐mapping scheme. The Cam‐clay plasticity model is adopted as a specific prototype model of geomaterials. As a pertinent representation of deformation‐induced anisotropy in geomaterials, nonlinear rotational hardening is incorporated into the model in a theoretically reasonable manner by introducing the dual multiplicative decompositions of the deformation gradient tensor. In addition to the usual decomposition into elastic and plastic parts, the plastic part is decomposed further into a part contributing to the rotational hardening and a remainder part. The former part leads to a back stress ratio tensor related to the rotational hardening via a hyperelastic‐type hardening rule. The constitutive theory is thereby formulated on proper intermediate configurations entirely in terms of deformation‐like tensorial variables possessing invariance property, without resort to any objective rates of stress or stress‐like variables. Combining the Cam‐clay plasticity with the concept of subloading surface, a class of unconventional plasticity, enables the model to be capable of reproducing complex hardening/softening accompanied by volumetric contractive/dilative responses. Basic characteristics and predictive capability of the proposed model, as well as the accuracy of the developed numerical scheme, are verified through several numerical examples including monotonic and cyclic loadings. [ABSTRACT FROM AUTHOR]

Measured force-displacement sensing data are analyzed to create nonlinear hysteretic models for elastic sliding bearings and steel dampers. These data were collected during full-scale experimental tests of a base-isolated structure at Japan's National Research Institute for Earth Science and Disaster Resilience (NIED) "E-Defense" Hyogo Earthquake Engineering Research Center in 2013 that employed historical and synthetic earthquake inputs. Several models are explored for each isolation-layer device, including Coulomb friction models for the elastic sliding bearings and Bouc-Wen hysteresis models for both devices. Parameters for each device model are estimated via constrained nonlinear optimization to minimize model prediction error using testing data. The resulting models are applied to data from other seismic tests to evaluate the models' ability to provide accurate force predictions. The model for the steel dampers demonstrates the capacity to be generalized across seismic excitations and devices, whereas the model for the elastic sliding bearing reproduces well its behavior during other seismic excitations but is limited to the device to which it was calibrated. The residual error between the model predictions and measurements does not contribute a significant degree of variance in the model parameter estimates. [ABSTRACT FROM AUTHOR]

The application of a recent field theory of deformation and fracture to nondestructive testing (NDT) is discussed. Based on the principle known as the symmetry of physical laws, the present field theory formulates all stages of deformation including the fracturing stage on the same theoretical basis. The formalism derives wave equations that govern the spatiotemporal characteristics of the differential displacement field of solids under deformation. The evolution from the elastic to the plastic stage of deformation is characterized by a transition from longitudinal (compression) wave to decaying longitudinal/transverse wave characteristics. The evolution from the plastic to the fracturing stage is characterized by transition from continuous wave to solitary wave characteristics. Further, the evolution from the pre-fracturing to the final fracturing stage is characterized by transition from the traveling solitary wave to stationary solitary wave characteristics. In accordance with these transitions, the criterion for deformation stage is defined as specific spatiotemporal characteristics of the differential displacement field. The optical interferometric technique, known as Electronic Speckle-Pattern Interferometry (ESPI), is discussed as an experimental tool to visualize those wave characteristics and the associated deformation-stage criteria. The wave equations are numerically solved for the elastoplastic stages, and the resultant spatiotemporal behavior of the differential displacement field is compared with the experimental results obtained by ESPI. Agreement between the experimental and numerical results validates the present methodology at least for the elastoplastic stages. The solitary wave characteristics in the fracturing stages is discussed based on the experimental results and dislocation theory. [ABSTRACT FROM AUTHOR]

Summary: Full‐scale dynamic testing and earthquake engineering experiments are often costly, yet they are vital for advancing the understanding of the complex interactions between seismic protective systems and structural responses. E‐Defense (a part of the Japan's National Research Institute for Earth Science and Disaster Resilience) constructed and tested a four‐story reinforced‐concrete base‐isolated building to study, among other things, how different anti‐seismic devices in the isolation layer of a building improve its response. This structure was subjected in August 2013 to a series of tests, including random ground motions and simulated earthquakes. Analyzing the acceleration responses from these random excitations forms the first step in identifying the dynamic characteristics of this test structure. The advanced numerical algorithm for subspace state‐space system identification (N4SID), from the family of subspace identification methods, is used to estimate the nominal modal parameters of this structure for both input–output and output‐only models. These models are then evaluated for their generalizability by using them to predict the response of the structure to both random excitations and seismic inputs. Additional identification is performed using responses recorded during simulated earthquakes, and the recovered modal parameters are compared against the nominal parameters to analyze how the building's isolation system impacts its response. The results indicate that the interaction between seismic excitation and the base‐isolation layer has both local and global structural effects. Locally, the modes most directly associated with isolation layer displacements experience, as expected, significant decreases in frequency and increases in damping; globally, the modes with more substantial displacements across the superstructure also experience decreases in frequency and increases in damping but at a greatly reduced scale. Further, even in the presence of seismic forces large enough to induce nonlinear restoring forces in the isolation layer, the relative changes in identified modal parameters for the superstructure associated modes remained modest. [ABSTRACT FROM AUTHOR]

Summary: A full‐scale 5‐story steel moment frame building was subjected to a series of earthquake excitations using the E‐Defense shake table in August, 2011. For one of the test configurations, the building was seismically isolated by a hybrid system of lead‐rubber bearings and low friction roller bearings known as cross‐linear bearings, and was designed for a very rare 100 000‐year return period earthquake at a Central and Eastern US soil site. The building was subject to 15 trials including sinusoidal input, recorded motions and simulated earthquakes, 2D and 3D input, and a range of intensities including some beyond the design basis level. The experimental program was one of the first system‐level full‐scale validations of seismic isolation and the first known full‐scale experiment of a hybrid isolation system incorporating lead‐rubber and low friction bearings. Stable response of the hybrid isolation system was demonstrated at displacement demands up to 550 mm and shear strain in excess of 200%. Torsional amplifications were within the new factor stipulated by the code provisions. Axial force was observed to transfer from the lead‐rubber bearings to the cross‐linear bearings at large displacements, and the force transfer at large displacements exceeded that predicted by basic calculations. The force transfer occurred primarily because of the flexural rigidity of the base diaphragm and the larger vertical stiffness of the cross‐linear bearings relative to the lead‐rubber bearings. [ABSTRACT FROM AUTHOR]

This study reports the application of an optoacoustic method for evaluating the bonding strength of ultrasonically bonded joints in a non-destructive and non-contact fashion. It is proposed that the bonding strength is correlated with the resonant frequency of bonded joints. The bonding strength measured with a destructive tensile test roughly increased with the vibration time, however, it varied, causing the transitional and dispersed formation of micro-bonds at the bonding interface. Scanning Electron Microscopic observation of the fractured surface suggested that the bonding strength depends on the total bonded area of micro-bonds. Frequency response of the bonded joint was examined with a non-destructive method using a piezo-electric vibrator. The experiment revealed that the resonant frequency exponentially increased with the bonding strength. In addition, this vibration behavior was dynamically visualized with electronic speckle pattern interferometry (ESPI). The correlation between the bonded area and the resonant frequency is discussed based on finite element analysis. The results indicate the possibility for in-situ evaluation of the ultrasonic bonding strength. [ABSTRACT FROM AUTHOR]

Ultrasonic welding of mild steel sheet (SPCC) and aluminium alloy sheet (A5052) was conducted using two different weld tips of a knurled tip (K-tip) and a curved shape tip without knurled edges (C-tip). Behaviours of the weld tip and the welded materials during the weld process were analysed using a high-speed camera observation and an image correlation. The C-tip welding shows a completely different displacement behaviour from the K-tip welding; a relative motion between the tool tip and A5052 in contact with the tip predominantly occurs in the C-tip in contrast to a relative motion between A5052 and SPCC observed in the K-tip. The joint strength using the C-tip was higher than that using the K-tip under the weld conditions in this study. It is demonstrated that the relative motion behaviour in the C-tip causes a macroscopic deformation of A5052 in the vibration direction. This phenomenon promotes growth of a bonded region, resulting in the increase of joint strength. It is surmised that Fe-Al intermetallic layer forms at the weld interface, and the joint strength consequently decreases for the longer weld time condition. [ABSTRACT FROM AUTHOR]

Authors tried to braze magnesium alloy in air using no flux with the aid of ultrasonic vibration, and investigated the effect of brazing conditions on the joint properties. The main results obtained in this study are as follows. Applying ultrasonic vibration made it possible to braze the magnesium alloy in air without flux and the joint strength was so high that the joint fractured partially in the base metal. The brazing temperature at which solid and liquid phases coexisted in filler metal could provide the brazed joint with the maximum tensile strength. This seemed to be because the liquid phase in the filler metal infiltrated into the cracks occurring in the oxide film on the faying surface during heating and the solid phase would rub against the oxide film to detach, resulted in removing the oxide film from the faying surface. The optimal time for applying ultrasonic vibration could effectually detach and remove the oxide film from the faying surface. The excessive applying time of ultrasonic vibration caused defects such as cavity formation in the brazed layer and led to decrease the joint strength. [ABSTRACT FROM PUBLISHER]

SUMMARY The accuracy of a series spring model to predict the peak displacement and displacement history of Triple Pendulum™ (TP) bearings in a strongly shaken, full-scale building is evaluated in this paper. The series spring model was implemented as a self-contained three-dimensional TP bearing element in OpenSees and is now available for general use. The TP bearing element contains the option for constant friction or a generalized friction model that accounts for the effect of instantaneous velocity and compression load on the friction coefficient. Comparison between numerical simulation and experimental data of a five-story steel moment frame building shows that the peak displacement of isolation system can generally be predicted with confidence using a constant friction coefficient model. The friction coefficient model accounting for the effect of axial load and velocity leads to minor improvement over the constant friction coefficient models in some cases. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

E-Defense shake table experiments on a 7.5 m tall, 1.8 m by 1.8 m square bridge column using polypropylene fiber-reinforced cement composites (PFRC) at the plastic hinge region and part of the footing is presented. The column was excited using 80% of the original intensity of the near-field ground motion recorded at the JR Takatori Station during the 1995 Kobe, Japan earthquake. Use of PFRC mitigated cover and core concrete damage, local buckling of longitudinal bars, and deformation of ties even after six times of repeated excitation. The damage sustained was much less than the damage of regular reinforced concrete columns. [ABSTRACT FROM PUBLISHER]

This article presents the seismic performance of scaled bridge columns using polypropylene fiber reinforced cement composite (PFRC), steel fiber reinforced concrete (SFRC), and reinforced concrete (RC) in combination with high strength longitudinal bars. The columns were subjected to combined axial and bilateral cyclic loading. Use of PFRC and SFRC mitigated damage of cover and core concrete, local buckling of longitudinal bars and strains induced in ties compared with the RC column. Damage mitigation and lateral confinement effect was superior in PFRC than SFRC. While PFRC and SFRC reduced the damage, their flexural strength and ductility capacity were similar with the RC column. [ABSTRACT FROM AUTHOR]

Licorice ingestion, as well as mutations in the HSD11B2 gene, inhibits 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2) enzyme activity, causing the syndrome of apparent mineral corticoid excess (AME). However, the combined effect of licorice ingestion and an HSD11B2 mutation has never been reported, until now. In this study, we demonstrated that licorice ingestion can produce overt hypertension in an individual without medical history of hypertension who is heterozygous for wild-type and mutant HSD11B2 genes. Our patient was a 51-year-old female with serious hypertension who had been taking herbal medicine containing licorice for more than one year. She was clinically diagnosed as having licorice intoxication, because she did not present with hypertension after ceasing the herbal medicine. Molecular analysis showed that she carried a missense mutation, c.40C>T, in HSD11B2. In conclusion, licorice ingestion is an environmental risk factor for hypertension or AME state in patients with a mutation in HSD11B2. Carrying a mutation in HSD11B2 is, conversely, a genetic risk factor for licorice-induced hypertension or AME state. Herbal medicine containing licorice may, therefore, be contraindicated in patients with an HSD11B2 mutation. [ABSTRACT FROM AUTHOR]

To explore severe toxicities induced by irinotecan-based chemotherapy and UGT1A1* 6/* 28 and SLCO1B1* 15/* 15 genotypes. A 66-year-old Japanese male diagnosed with left pharyngeal carcinoma (T2N2bM0, stage IVA) was treated with irinotecan (70 mg/m2) on days 1, 8 and 15 in combination with docetaxel (60 mg/m2) on day 1 of a 28-day cycle. After the first cycle, he suffered marked toxicities, including grade 4 diarrhea and febrile grade 4 neutropenia. Plasma concentrations of irinotecan, SN-38 and SN-38G were measured, and extensive accumulation of SN-38 was observed. Genotyping of UGT1A1 and OATP1B1 proteins showed UGT1A1* 6/* 28 and SLCO1B1* 15/* 15, respectively, which are known to lead to extremely low glucuronidation and transport activities of substrate drugs. The severe toxicities in this patient are attributable to the extensive accumulation of SN-38, which may result from a synergistic or additive effect of low metabolic ( UGT1A1* 6/* 28) and transport ( SLCO1B1* 15/* 15) capabilities. [ABSTRACT FROM AUTHOR]

Abstract: The dissociation mechanism of excited CH2X2 (X=Cl, Br) was investigated using charge-inversion mass spectrometry, in which positive ions collide with an alkali metal target to generate neutral fragments, and the negative ions formed from the neutral fragments are mass analyzed. Different relative abundances of the negative ions were observed in the charge-inversion spectra for CH2Cl2 and CH2Br2. The kinetic energy release values calculated from analysis of the peak associated with in the charge-inversion mass spectrum of the parent ion indicate that the excited CH2Cl2 formed by neutralization dissociates spontaneously into CHCl2 +H. [Copyright &y& Elsevier]

The deformation and fracture mechanism in 7075 aluminum alloy is discussed based on a field theoretical approach. A pair of peak-aged and overaged plate specimens are prepared under the respective precipitation conditions, and their plastic deformation behaviors are visualized with two-dimensional electronic speckle pattern interferometry (ESPI). The in-plane velocity field caused by monotonic tensile loading is monitored continuously via the contour analysis method of ESPI. In the plastic regime, the peak-aged specimen exhibits a macroscopically uniform deformation behavior, while the annealed specimen exhibits non-uniform deformation characterized by a localized shear band. The occurrence of the shear band is explained by the transition of the material's elastic resistive mechanism from the longitudinal force dominant to shear force dominant mode. The shear force is interpreted as the frictional force that drives mobile dislocations along the shear band. The dynamic behavior of the shear band is explained as representing the motion of a solitary wave. The observed decrease in the solitary wave's velocity is accounted for by the change in the acoustic impedance with the advancement of plastic deformation. [ABSTRACT FROM AUTHOR]

A method to diagnose the deformation status of solid objects under loading is discussed. The present method is based on a recent field theory of deformation and fracture and optical interferometry known as the Electronic Speckle-Pattern Interferometry (ESPI). Using one of the most fundamental principles of physics referred to as symmetry in physics, this field theory formulates all stages of deformation and fracture on the same theoretical basis. In accordance with the formalism, the theory has defined the criteria for different stages of deformation (linear elastic, plastic and fracturing stages) expressed by certain spatiotemporal features of the differential displacement (the displacement occurring during a small time interval). The ESPI is used to visualize the differential displacement field of a specimen as two-dimensional, full-field interferometric fringe patterns. This paper reports experimental evidence that demonstrates the usefulness of the present method. A tensile load is applied to an aluminum-alloy plate specimen at a constant pulling rate and the resultant in-plane displacement field is visualized with a two-dimensional ESPI setup. The differential displacement field is obtained at each time step and the interferometric fringe patterns are interpreted based on the criterion for each stage of deformation. It has been found that the criteria of linear elastic deformation, plastic deformation and fracturing stage are clearly observed in the corresponding fringe patterns and that the observations are consistent with the loading characteristics. [ABSTRACT FROM AUTHOR]

This paper discusses a non-destructive measurement technique of residual stress through optical visualization. The least amount of deformation possible is applied to steel plates by heating the specimens +10 °C from room temperature for initial calibration, and the thermal expansion behavior is visualized with an electronic speckle pattern interferometer sensitive to two dimensional in-plane displacement. Displacement distribution with the thermal deformation and coefficient of thermal expansion are obtained through interferometric fringe analysis. The results suggest the change in the thermal deformation behavior is affected by the external stress initially applied to the steel specimen. Additionally, dissimilar joints of steel and cemented carbide plates are prepared by butt-brazing. The residual stress is estimated based on the stress dependence of thermal expansion coefficient. [ABSTRACT FROM AUTHOR]

A cylindrical tool was applied for ultrasonic bonding of multi-layered copper foil and a copper sheet to prevent damage to the foil during bonding. The strength of the joints bonded with the cylindrical tool was comparable to that of the joints bonded with a conventional knurled tool. The effect of the cylindrical surface tool on bondability was investigated thorough relative motion behaviors between the tool surface and the bonding materials, as well as on bond microstructure evolution. The relative motion was visualized with in-situ observation using a high-speed camera and digital image correlation. At shorter bonding times, relative motions occurred at the bonding interfaces of the foil and the copper sheet. Thereafter, the relative motion between the tool and the bonding material became predominant owing to bond formation at the bonding interface, resulting in a macroscopic plastic flow in the bonded region. This relative motion damaged the foil in knurled tool bonding, and the cylindrical tool achieved bonding without any damage. [ABSTRACT FROM AUTHOR]