An electroplating spring-bridge micro-tensile specimen is demonstrated and fabricated here. The specimen is fit into a specially designed micro-mechanical apparatus to carry out a series of tensile testing on sub-micron freestanding thin films. Freestanding thin films were then loaded by performing monotonic loading/ unloading up to 20 μm/(10^<-1>s) and tension-tension fatigue experiments at 25 Hz up to 〜10^5cycles. Loading was applied using a piezoelectric actuator with 0.1 μm resolution connected through pin hole into the test chip. Loads were measured by connected specimens through a pin connected rod using its bottom pivot to transfer loads and displacement from sample load sensing beam into a capacitor load cell. For the monotonic loading/unloading experiments, we found the modulus of copper thin films with thickness of 200 nm at ambient temperature. Displacement controlled tension-tension fatigue experiments on copper thin films have also been performed and a trend of decreasing cycles to failure with increasing mean displacement has been noted but requires further experimental exploration.

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This paper describes fabrication and characterization of MEMS hermetic package with lead-free solder film line heated by using exothermic Al/Ni multilayer structure. The Al/Ni structure deposited by DC magnetron sputtering shows self-propagating exothermic reaction. By applying a spark, the reactive structure generates heat enough to melt solder film. The heat of reaction depended on Al/Ni bilayer thickness and the total film thickness. We used the Al/Ni structure as a local heat source for MEMS soldering packages. The solder film-bonded silicon elements using the local heating were fabricated without other external heat sources. The bond strength examined by blister test was evaluated on the basis of weibull statistics.

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This paper describes an experimental analysis of surface stress distribution on single crystal silicon (SCS) microstructures using laser Raman spectroscope. A handmade tensile tester was employed to apply a uniaxial tensile stress to SCS specimen with a 270 nm-height and 4 μm-square SCS boss in the gauge section. In room temperature, Raman spectroscope measured surface stress, applied by the tensile tester, around the boss. The stress distribution obtained from two-curve fitting of Raman spectrum was in good agreement with that estimated by finite element analysis (FEA).

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Recent advances in the electronics industries are drove by the rapid advancement of LCD technology. However, warpage is one of the major reliability and quality concerns in chip-on-glass (COG) packaging. Optical technique combined with microscopes is an obvious candidate for the non-contact measurement of warpage of LCD chips whose profiles vary from nanometers to micrometers. In this paper, projection speckle correlation method and Newton's ring interferometry are employed to obtain the warpage of a LCD chip. With respect to projection speckle correlation method, the technique of image merging is necessary in registrating of 3D shape of entire object. Continuous wavelet transform (CWT) is employed to extract 3D profile of the electronic chip by analyzing the phase of the experimental fringe patterns. Phase retrieval is performed by computing the phase at a wavelet ridge. In addition, the points which introduce phase ambiguity are identified by tracking the inflexion points on the unwrapped phase map and detected by Savitzky-Golay differential operator. The feasibility of the proposed method is also validated by simulations. Experimental results from both techniques are compared, and excellent agreement is found. Above conclusions demonstrate that the techniques proposed in this study are powerful inspection tools for measuring warpage of LCD chips.

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A optical method for evaluating the natural frequency and the quality factor (Q) of a microstructure is proposed in this paper. The proposed method is based on ultrasonic wave excitation which is a non-contact technique and does not impose undefined loadings. The images of a microstructure vibrated ultrasoniclly are captured by a CCD camera at different frequencies. The vibrational amplitudes of the microstructure are subsequently extracted using edge detection based on a Mexican Hat wavelet transform and an amplitudefrequency spectrum is obtained from which the resonant frequency is determined. The damping characteristic is evaluated subsequently using a half-power method. A silicon microstructure consisting of a perforated crossbeam (205μmX26μm) and a cantilever beam (220μmX23μm) is tested. The thickness of the microstructure is approximately 3μm. The experimental set up is relatively simple and the results show that the proposed method is an effective approach for evaluating the dynamic characteristics of a microstructure.

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In this study, the new and simple crack length measurement method by using grid pattern of Au film was suggested. Au film coated on the surface of a specimen by the ion sputtering method was cut like a comb by scanning laser beam condensed as a line, and the fine grid pattern film with the grid width, 10μm, and space width, 7μm, was made. Further, to confirm the validity of the method the crack growth test was carried out with four-point bending using soda-lime glass specimens. As a result, it was confirmed that the crack length measurement using the fine grid pattern film could express the relationship between the crack growth rate and stress intensity factor of the material in detail, and the possibility of the application to the other ceramic materials was also showed.

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Corrosion fatigue crack initiation tests using 13Cr stainless steel were carried out in synthetic seawater to investigate the corrosion fatigue crack initiation life (Nc). For this purpose, direct observation of the crack initiation, which emanated from the corrosion pit, was carried out. Especially, for one specimen, crevice corrosion condition was set to induce the occurrence of the corrosion pit on the supposed observation area. In addition, a corrosion fatigue crack initiation and propagation model was suggested. Until now, corrosion fatigue crack initiation life was treated ambiguously. The important point of the model is the suggestion of the moment of the corrosion fatigue crack initiation life at which the critical size of the corrosion pit changes to the crack. As the crack which emanates from the pit is usually small, accordingly it is treated as a small crack using intrinsic crack model. Assuming the corrosion pit to be a small crack, evaluation of the critical condition of corrosion fatigue crack initiation was carried out by comparing stress intensity factor (ΔK) and crack length dependent threshold stress intensity factor [(ΔKth)s]. From the result of this research, it was found that the critical condition of corrosion fatigue crack initiation can be estimated by the evaluation of threshold stress intensity factor [(ΔKth)s] using intrinsic crack model. Finally, the followings were obtained. When there is no clear stress concentration point which seems to fall into a corrosion fatigue crack initiation life, the very moment when the fatigue crack propagation rate becomes faster than the corrosion pit growth rate so that the fatigue crack initiates from the pit and propagates in earnest can be defined and clarified as the reasonable and universal corrosion fatigue crack initiation life (Nc).

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CoNiCrAlY protective coatings are used for insulation from corrosion and oxidation of super alloy substrates in gas turbine blades. The life of a gas turbine blade is significantly affect by the mechanical properties of the protective coating. However, the properties of the coatings themselves have not been clarified, because there are few proper measurement methods for thin coatings. In this study, uniaxial stress-strain responses of atmospheric plasma sprayed (APS) CoNiCrAlY coatings were examined. The coating specimen was tube with the thickness of 0.3 mm. Coating specimens independent of substrates were fabricated by dissolving out the substrates only at the region of gauge area by nitric acid. The stress-strain response was measured using the laser speckle strain measurement method. The coating showed the significant nonlinear stress-strain response. The rigidity increased with an increase of applied compressive stress, and the coating left permanent strain when the compressive stress was relieved. The nonlinearity was decided by the surface roughness which represented the amount of defects in the coating. Nonlinearity of stress-strain response becomes significant if the surface roughness increases. Oxidation ratio was not related with nonlinearity. As compared with low pressure plasma sprayed (LPPS) CoNiCrAlY, the Young's modulus of APS CoNiCrAlY was lower, and total strain was higher. There were not significant differences between the stress-strain response at 873K and that at R.T.

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In order to clarify the thermal and / or mechanical failure behavior of the plasma sprayed thermal barrier coating (TBC) system in connection with their coating characteristics such as the coating microstructures and interfacial natures depending on the coating process condition, two kinds of the failure analytical tests were conducted for TBC systems processed under different conditions. One was the high-temperature oxidation test, which was conducted at 1100℃ under both the isothermal and thermal cycle conditions. The other was the in-situ observation of mechanical failure behavior, which was conducted under the static loadings at ambient temperature; as the most fundamental aspect, by means of an optical microscopy. It was found that the thermal and mechanical failure behavior of TBC system depends strongly on the top-coat (TC) / bond-coat (BC) interfacial condition, the sorts of BC spraying process, the reheat-treatment (RHT) after spraying and so on. For the TBC system with vacuum plasma sprayed (VPS) BC as well as for that with air plasma sprayed (APS) BC, in particular, the RHT at an appropriate temperature in Ar atmosphere was found to be effective for improving the oxidation property. For the TBC system with APS-BC, however, it was impossible to prevent the crack growth into the BC interior under the tensile loading in spite of conducting the RHT, since the microdefects such as oxides and micropores within the APS-BC tend to provide an easy crack propagation path. In addition, it was clarified that the smoothening process on the BC surface is able to prevent perfectly the occurrence of the wart-like oxide (WO) during oxidation, but at the same time increases also the risk of the TC spalling under the mechanical loading. Furthermore, the effect of the coating process condition on the TC spalling resistance was discussed.

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Kinetic Metallization (KM), which is one of the spraying systems for particle deposition, has been studied as a new system of bond coatings of Thermal Barrier Coatings (TBCs) for components used in hot section of advanced gas turbine systems. In this paper, mechanical and oxidation properties including residual stress of Atmospheric Plasma Sprayed (APS) YSZ top coating with two different bond coating spraying systems, Low Pressure Plasma Spraying (LPPS) and KM, were evaluated and compared in thermal cycle tests. From the results, in case of the CoNiCrAlY bond coating sprayed by KM, the porosity is less than 4.2%. The relatively less oxidation layer is observed due to its higher density and more stable oxide growth. And, the variation range of residual stress of TBC with KM bond coat is narrower than that of LPPS relatively. This effect is assumed that bond coating by KM behaved elastically due to dense coatings.

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Effect of MCrAlY bond coat alloy systems on thermal fatigue failure of thermal barrier coatings (TBCs) was investigated, where the TBC specimen consists of Ni-based superalloy IN738 substrate, bond coat, and 8 wt.% Y_2O_3-stabilized ZrO_2 (YSZ) topcoat. The top coat was fabricated by EB-PVD method with 250 μm in thickness. Three kinds of MCrAlY alloys were studied as the bond coat material. Employing the originally developed test equipment, the thermal fatigue tests were carried out, by applying thermal cycles between 400 and 950℃ in air. Special attention was paid not only to the failure lives themselves, but the underling failure mechanisms. The experimental results clearly demonstrated that the effect of MCrAlY bond coat alloys on the thermal fatigue life was very significant. Some mechanical and material backgrounds of these experimental results were discussed, based on the measurements of the mechanical and metallurgical properties of the bond coat: i.e., elastic stiffness, thermal expansion coefficient and high temperature oxidation resistance.

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Diamond films were synthesized on a Mo substrate using combustion flame. During the cooling process, most diamond films delaminated. From previous work it has been shown that a three-step method using combustion flame was viable to prevent a delamination. But it was not perfect. In order to get a good adhesion of the diamond film, distances of the flame inner cone from the substrate were changed for each step of the three-step method. The first step of the three-step method was set to the distance d=1.5mm, the second step was set to the distance d=2.0mm and the third step was set to the distance d=3.0mm, respectively, with each scratching treatment of #180, 400, 800 and 1500 of the substrate surface. The results showed that the good adhesion of the diamond film was obtained at scratching treatments #400, 800 and 1500. An abnormal growth of the film did not occur by the changing distances. The inspection by SEM and XRD showed that synthesized films at the scratching treatment #400, 800 and 1500 by the changing distances were good diamond. It was concluded that the delamination-free diamond film could be realized by changing the distances.

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Spinal fixation is a common surgical method to stabilize the unstable spines using internal devices. However, excessive intervertebral motions and stresses of adjacent segments are produced. The potential use of dynamic stabilization as a novel approach to spinal fixation is currently being investigated. In this study, the virtual biomechanical test of a new spinal fixation instrument for dynamic stabilization was presented. Finite element models of an intact lumbar spine and two spinal fixations using Ti rods and SMA springs were developed. The intersegmental rotation, ligament tension force, contact force on the facet joint, and the von Mises stress on the intervertebral disc were predicted under the flexion and extension. The results showed that the spinal motion could be recovered and the maximum von Mises stress levels on the intervetebral disc, ligament tension force, and the contact force on the facet joint could be greatly reduced at the adjacent segments in the dynamic stabilization using the SMA springs in comparison with those in the rigid fixation using the Ti rods. This result agrees with the clinical experience and indicates that the spinal fixation under dynamic stabilization was more clinically appropriate. Moreover, the virtual biomechanical test technology can provide a useful tool for not only the decision of the surgical options in spinal fixation but also the development of new medical implants.

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Frictional wear resistance is one of the important properties of metallic biomaterials. Surface hardening treatments such as oxidizing, nitriding and ion implantation tend to be applied for improving the wear resistance of titanium and its alloys. The gas nitriding process is expected to further improve the wear resistance of newly developed β-type Ti-29Nb-13Ta-4.6Zr alloy (TNTZ). However, it is also possible to degrade the mechanical performance such as tensile and fatigue strength of TNTZ thorough their processes. Therefore, the gas nitriding process was carried out in this study to improve the wear resistance of TNTZ and an α+β type Ti-6Al-4V ELI alloy (Ti64), which is one of the titanium alloys applied for medical applications, in simulated body fluid (Ringer's solution). The change in their tensile and fatigue properties were also investigated in order to confirm the reliability as biomedical materials. The Vickers harnesses near the specimen surface of nitrided TNTZ and Ti64, where TiN and Ti_2N forms, increases significantly as compared to that of their matrices. The wear resistances of TNTZ and Ti64 are improved significantly in Ringer's solution by nitriding process as compared to those of as-solutionized TNTZ (TNTZ_<ST>) and Ti64. The tensile strength of nitrided TNTZ increases by around 90 MPa as compared to that of TNTZ_<ST>. The tensile strength of nitrided Ti64 does not change significantly at all nitriding temperatures. On the other hand, their elongation decrease with increasing the nitriding temperature. The runout (plain fatigue limit) of TNTZ subjected to a nitriding process at 1223 K was around 300 MPa, and was 75 MPa higher than that of Ti64 subjected to a nitriding process at 1223 K although the tensile strength of the nitrided TNTZ was 200 MPa smaller than that of the nitrided Ti64. The run out is a little smaller than that of TNTZ_<ST>.

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Plain and fretting fatigue characteristics of dental low-noble Ag-Pd-Au-Cu-Zn (S-12) alloys with different microstructures obtained by solution treatment and aging after solution treatment were investigated. In addition, the fracture surface and the surfaces of the specimen and pad after the fretting tests were also examined. The fretting fatigue strength of the S-12 alloy subjected to both heat treatments is lesser than its plain fatigue strength especially in the high cycle fatigue life region. The fretting fatigue strength of the S-12 alloy aged after the solution treatment is less than that of the one subjected only to solution treatment. Small fretting fatigue cracks initiate at the wear scars; these cracks link with each other, thereby leading to the main crack.

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Metallic biomaterials are utilized in artificial hard tissues for medical applications. However, the Young's moduli of conventional metallic biomaterials are much higher than those of hard tissues. Thus, metallic biomaterials are required to have low Young's moduli, similar to those of hard tissues. Porous metallic materials, in comparison to bulk materials, are expected to exhibit lower Young's moduli; however, certain mechanical properties of porous materials decrease with an increase in their porosity. A polymer filling is a likely option to improve the mechanical properties of these porous metallic materials by preventing the stress concentration at the pore necks. Thus, in this study, the pores in porous pure titanium were filled with a medical polymer (polymethylmethacrylate: PMMA). Both pure titanium and PMMA are used in practical biomedical applications. The porous pure titanium/PMMA composite was fabricated by a simple process as follows. The air in the pores of a sintered compact of gas-atomized pure titanium powder (porous pure titanium) was removed by soaking the compact in a methylmethacrylate (MMA) monomer solution mixed with 2,2'-azobisisobutyrylnitrile (AIBN) as a polymerization initiator under reduced pressure at room temperature. Next, polymerization was carried out by heating to a constant temperature. The conditions of porous pure titanium (powder size, porosity, etc.) were systematically changed, after which the effects of the polymer filling on the mechanical properties of the porous pure titanium were investigated.

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The objective of this study was to use the dynamic nanoindentation method to determine viscoelastic properties such as storage modulus and loss tangent of single osteons and interstitial lamellae of rat femoral cortical bone tissue at the microstructural level in a longitudinal direction. The effects of mineral, organic and water contents of bone specimens on viscoelastic properties at the macroscopic level were also investigated. The storage moduli of osteons were significantly lower than those of interstitial lamellae, however, the loss tangents of osteons were higher than those of interstitial lamellae of bone tissues. A correlation was found between the storage modulus and mineral content of rat cortical specimens. Likewise, a linear correlation was also demonstrated between the loss tangent and the organic and water contents of specimens.

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To examine and diagnose osteoporosis, it is essential to obtain morphological architecture of the bone (2000 NIH suggestion, USA), which permits the estimation of fracture risk based on biomechanics. However, conventional method uses some indices such as bone mineral density (BMD) of the spine and its contour distortion level by the DXA method (X-ray picture). As an acoustic method, the broadband ultrasound attenuation (BUA) of propagating wave, speed of sound in the bone (SOS), and area fraction of bone calculated from the SOS have been used. However, those indices have no mechanical index. The objective is the development of a new visualization technique for morphological architecture of bone (micro-architecture) using ultrasound signals. In first, we established a visualization technique using some spongy-shaped architecture specimens. Then we demonstrated in vivo human heel bone to clarify the validation of this technique. The visualization technique was capable to create 3-dimensional image with the size of 〜5 mm depths from the surface of cortical bone.

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This study aims at developing an accurate method for analyzing in vivo knee kinematics using single plane fluoroscopy and 3D bone models. The study was carried out on 3 porcine knees. Three sphere markers were fixed to both femur and tibia. A CT scan was acquired for each bone to create a 3D bone model. After being CT scanned, the femur and tibia were fixed using an external fixation device, resembling anatomical positions of knee. Ten single plane fluoroscopic images of 3 sets of fixed bones were obtained with different flexion angles and different directions of image acquisition. Digitally reconstructed radiographs (DRRs) were generated from 3D bone volume models by a voxel projection technique. The relative 3D-pose (full 6 degrees-of-freedom parameters) between femur and tibia were determined by matching the DRR of each bone model with the fluoroscopic image by maximizing the similarity measure between the 2 images. The true value of the relative pose was measured by a 3D coordinate measuring machine. The mean errors of the 3 rotation parameters were within 0.5 degrees. For the translation parameters the mean error took its maximal value of 1.5 mm in the out-of-plane direction. The result obtained shows a potential of the proposed method for the accurate analysis of in vivo knee kinematics.

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In order to evaluate the influence of injury to the intervertebral disc, supraspinal ligament, interspinal ligament, and facet joint on the spinal deformation, we conducted a bending test in a total of 8 directions, i.e., flexion, extension, right lateral bending, left lateral bending, right anterolateral bending, left anterolateral bending, right posterolateral bending, and left posterolateral bending, using the 6-axis material testing machine we developed for this study. The study closely investigated changes in the range of motion (ROM) of the functional spinal unit (FSU) associated with injury using 2 FSUs of the lumbar spines obtained from human cadavers. The results showed that when the intervertebral disc was injured, the ROM increased equally in all directions. When the supraspinal ligament and interspinal ligament were injured, the ROM increased only in the flexion. When the facet joint was injured, the ROM increased in the flexion and extension. These finding indicated that, in the ROM of the lumbar vertebrae, the intervertebral disc was involved in all directions, and the supraspinal ligament and interspinal ligament were involved mainly in the flexion, while the facet joint was involved mainly in the flexion and extension.

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Three-dimensional (3D) bone surface models reconstructed from computed tomography (CT) scan data have been used for surgical planning and intra-operative registration. Although CT scanning is an excellent technique for describing bone structure and geometry, it has disadvantages of radiation exposure and poor ability of visualizing soft tissues such as articular cartilage. Magnetic resonance (MR) is a powerful method for imaging soft tissues without radiation. Recently quantification of cortical bone structure and geometry has been investigated using MR imaging (MRI). The aim of the present study is to examine the precision of 3D MRI-based bone surface models. Porcine femora and tibiae were used for the study. Three polymeric spherical markers containing gadolinium contrast media were fixed to the femur and the tibia, respectively. MRI and CT scanning were performed with routine protocols. 3D bone surface models were reconstructed with a commercial software package. Actual bone dimensions were measured with a caliper at the cross sections where the markers were fixed. These dimensions were compared with those on MRI-based and CT-based models. The distances between two of the three markers were also compared. The maximum differences in dimension between actual bone and model were 2.6 mm for sagittal MRI, 1.4 mm for axial MRI and 0.8 mm for CT, respectively. Errors in the marker distance were within 1.0 mm for both MRI and CT models, showing no significant differences between both models. Automatic tracing of bone outlines may improve the accuracy of MRI models.

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This paper deals with an application of the near infrared (NIR) spectroscopy to quantitative measurement of the water content in human articular cartilage under compressive loading and unloading. Indentation test on human articular cartilage, and the subsequent measurement of the NIR absorbance at the wave length of 1.46 μm have been performed. Difference in time dependent recovery of the NIR absorbance between the normal and degenerated articular cartilage were investigated. The degenerated articular cartilage showed relatively high Mankin (MK) score, an index of cartilage degeneration, and the rapid recovery of the NIR absorbance, while low MK score and slow recovery of the NIR absorbance were observed in the normal articular cartilage. The relations between the NIR absorbance and water content, the NIR absorbance and thickness, and the NIR absorbance and water content per unit thickness were established. The cartilage showed no correlation between the NIR absorbance and water content, but showed the NIR absorbance was in proportion to water content per unit cartilage thickness. Linear relation between thickness and the NIR absorbance was found as well. From these results, water content in human articular cartilage was able to be formulated as a function of the NIR absorbance. It is concluded that non-destructive, low-invasive and quantitative estimation of water content in human articular cartilage can be performed using the NIR spectroscopy.

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The mastication simulator was developed to reproduce the bi-axial cyclic loading condition of in vivo dental implants in the laboratory experiment, and used in this study to evaluate the effect of the mastication loading on the retentive force of the temporary cement for cement-retained implant restoration. The in vivo loadings on the dental implant exerted by the typical mastication kinematics were evaluated by implanting a measuring dental crown coupled with strain gages to a male volunteer. Subsequently, the loading condition in the mastication simulator test was compared to results of the in vivo measurement to examine the validity of the mastication simulator. The in vivo measurement revealed that the dental implant was exposed to dynamic axial loading and simultaneously dynamic bending moment during the masticating motion and the loading condition in the mastication simulator was relatively close to the grinding condition. The results of this study indicated that the retentive force of the temporary cement was gradually degraded by applying the mastication loading. Therefore, the degradation behavior of the temporary cementation should be examined prior to the operation to ensure the crown retention.

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In this study, we aim at clarifying dental occlusion functions by visualizing the displacement and deformation patterns of the periodontium under dental occlusion. A digital image correlation method was employed as a visualization technique and a deformation analysis method. Fresh periodontium specimens from pigs were used as specimens. In addition to the occlusion test using fresh periodontium specimens, the same test was conducted using dried periodontium specimens, and the differences in displacement and deformation patterns between the fresh and dried periodontium specimens were evaluated. The experimental results show that periodontal ligaments deformed first, followed by alveolar bones under dental occlusion. We found that there were marked differences in displacement and deformation patterns between the fresh and dried periodontium specimens, and that the periodontal ligament plays an important role in dental occlusion functions.

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Polymerization contraction stress is associated with clinical failures of resin composite restoration. In order to improve long-term clinical outcome of bonded restorations, management of contraction stress is mandatory. It has been suggested that many factors are related to the magnitude of stress, therefore, contraction stress reduction is not a simple task. The purpose of this paper was to review the relevant literature to summarize current knowledge on contraction stress management.

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Many methods of particle tracking velocimetry (PTV) have been proposed for measuring three-dimensional (3-D) steady and unsteady flows. However, in these methods setting conditions of cameras and applying to 3-D flows are rather difficult. A novel measurement method of 3-D flow velocity is proposed in this study to overcome the difficulties. A marked square is taken in pictures from 2 directions together with flowing tracers. The configurations of two cameras and the position of each tracer can be determined through descriptive geometry by referring to the square. To examine the validity of this method, three types of measurements are conducted. First, the positions of the vertexes of stationary rectangular prisms are determined. Second, the motions of balls rolling down on an inclined plate are measured. Third, the 3-D motions of tracers around a small fan are measured.

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Efficient agitation of molten steel and slag is requested in the steelmaking industry. The conventional agitation methods are Ar gas injection and electromagnetic stirring. These methods are very expensive, and accordingly, we have proposed an alternative, cheap and effective mixing method using a swirl motion. This method does not need any driving devices in the reactor. In this study, we place a lowdensity liquid or low-density particles on a cylindrical water bath and investigate the effect of the upper layer on the amplitude of swirling liquid jet.

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This paper describes the interfacial phenomena generated on the gas-liquid interface. Details of the collision, rebound, and coalescence of small water droplets at the clean air-water interface were studied experimentally and theoretically. The behavior of the falling liquid drop in the air-water interface was observed with the high speed video camera system. It was found that the water drop at lower impact velocities floats on the air-water interface. When a larger water drop coalesces with water, the surface flow generated by the coalescence ejects the secondary smaller droplet of water. The maximum depth by the drop collision is described by the Froude number and the Weber number. The behavior of the coalescence wave on the water column and the satellite droplet produced by the break up of the water column was also revealed experimentally.

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In this study, pressure losses in three horizontal pipes of 25 mm, 52.7 mm and 80.1 mm in internal diameter in which two immiscible fluids (oil and water) were made to form a core-annular flow (CAF) were measured. Two types of viscous liquids (oil M680, viscosity of 2.82 Pa-s at 20℃ ; oil M1800, viscosity of 8.92 Pa-s at 20℃) were used in the experiment. The oil-water flow rate ratios (ratio of oil flow rate to water flow rate) were set at 2.6, 3.0, 3.4, 4.0 and 4.6 for the pipe of 25 mm in diameter and at 8.0 for the pipes of 52.7 mm and 80.1 mm in diameter. Based on the results of the experiment, an empirical equation was derived to estimate CAF pressure loss at various oil-water flow rate ratios and pipe diameters. The pressure losses obtained from the equation showed good agreement with the results of the experiment.

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An experimental study and a numerical modeling are conducted on a "Twin inclined jets in crossflow's" configuration in order to describe the jets' evolution through the crossing flow and to determine the different vortical and dynamic features characterizing the resulting flowfield. The experimental data are depicted by means of a PIV technique. Besides, a numerical three dimensional model of the studied configuration is simulated by means of the different equations governing the flow present in the domain and a turbulent closure model. We will essentially focus on the injection rate impact on the dynamic and thermal distributions; for the matter we tested the following blowing ratios values: 0.67, 1, 1.29 and 3. A confrontation of the numerical results with the experimental data is necessary for their validation. The studied features comprised the vortical structures contained in the jets' plumes, the windward and the leeward jets' spread, the size, the location and the magnitude of the reverse flow region, the penetration and the deflection of the jets' trajectories, the mass entrainment of the discharged pollutants from the jets' nozzles and finally the thermal distribution of some of the above mentioned parameters.

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Underwater shock waves are generated by uniform irradiation of pulsed laser beams onto the solid surfaces that are the end surface of a block made of piled thin plates. The shape of the end surface of the block is easily changed by sliding the piled thin plates. It is demonstrated that the pulsed laser irradiation onto the end surface made of piled thin plates is a good method to make shock waves with wave fronts of arbitrary shapes. The pulsed laser irradiation on solid surfaces makes shock waves that propagate perpendicularly to the surfaces, and the shock waves generated on a concave cylindrical surface focus on the axis of the cylinder. The duration of the shock waves is about 65ns at the focal point, and there appear negative pressure regions behind the shock waves.

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Experimental results from studies on the properties of ultrasonic propagation velocity and attenuation in hydrocarbon-based magnetic fluid are reported. The ultrasonic frequency used is 2 MHz and the measurement scheme is based on the pulse method. The external magnetic field intensity is varied from 0 to 550 mT and the angle between the magnetic field direction and the direction of ultrasonic wave propagation is adjusted from 0 to 90°. The ultrasonic propagation velocity and attenuation changes are dependent upon the intensity of the magnetic field and the elapsed time of application. Characteristic properties of ultrasonic propagation in magnetic fluid are observed. These particular results seem to be caused by clustering structures in the magnetic fluid. Based on these results, the inner structure of the magnetic fluid is analyzed experimentally and the application of non-contact inspection in opaque fluids by ultrasonic techniques is discussed.

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We investigate a penetration depth and a dispersion ratio of low-density particles to elucidate the dispersion behavior of low density particles under three mechanical agitation methods; centric agitation, offset agitation and centric agitation with an immersion cylinder. The penetration depth is defined as the maximum distance from the bath surface to the position at which the low-density particles arrive. The dispersion ratio is defined as the ratio of the number of low-density particles distributed in a certain part in the bath to the total number of particles. The penetration depth is influenced by the rotation frequency and the impeller diameter, but is not influenced by the impeller height nor the agitation methods.

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Experimental study has been conducted to clarify the internal and external pressure variation for KTX(Korea Train eXpress). Abrupt pressure variation gives rise to the ear-discomfort for passenger and fatigue for car body. In this study, the pressure variation of internal and external pressure variation are measured by using KTX and on-board portable data acquisition system in commercial line. The tunnels from 200m to 4000m in length are chosen for the investigation of tunnel length effects. From the results of experiment, the internal pressure variation rate for all the test tunnels is lower than the standard criteria of 200Pa/s. And, the critical tunnel lengths for pressure wave pattern are classified into 7 groups by using theoretical L-t diagram.

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In the paper, the investigation results of periodical gas-lift upward flows using experiment method are presented. The experiment facilities consist of flow measurement equipment, gas and fluid supplier facilities, tubing system. To study the influence of medium physical and dynamical characteristics on the process efficiency, two liquid-gas systems are used, namely, spindle oil-air and water-air. The objects of investigation are to obtain data from tests conducted in some conduits and to analyse the influence of system physical, geometrical and etc. parameters such as: initial liquid height in the conduits, gas injected volume, conduit diameter, conduit configuration and etc. on the considered process.

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Mixing of liquid in a container by gas injection is widely used in many industrial fields. For example, it has been utilized in steelmaking processes, chemical engineering processes and remediation of polluted sediments. We focus on the treatment of contaminated sediments on the bottom of bays and lakes using a swirl motion of a bubbling jet and ozone. In this study, we mention about the behavior of sediment lifted up by swirling bubbling jet generated with a J-shaped lance in a bottomless container. Investigation is carried out on the occurrence condition and basic characteristics of the swirling bubbling jet. The occurrence region is affected by the lifted sediments. The measured values of the basic characteristics can be approximated by empirical equations proposed previously for a bottom blown container without sediments. The period of the swirl motion can be satisfactorily approximated by the period of the rotary sloshing.

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Piezoresistance pressure sensor chips are micro-machined semiconductor devices that sense changes in pressure. The piezoresistance semiconductor pressure sensor is the product that consists of a sensor element forming the diaphragm and a circuit block for sensitivity adjustment and temperature compensation. In general, the static pressure hole is installed between the sensor and the pressure measurement point. The characteristics of the flow field in the pressure hole influence the performance of the sensor. In this paper, flow fields in pressure hole were analyzed numerically to find the optimal geometry. The influence of the outside flow velocity of the pressure hole was examined. The leakage of enclosed oil into piezoresistance pressure sensor was considered by numerical calculations of flow fields.

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The Single Point Incremental Forming (SPIF) process is an interesting innovative production technique for industries involved in metal forming and metal stamping. SPIF is based on the relative movement of a simple small punch with respect to the blank. The advantages of SPIF are a high flexibility and the fact that there is no need for a die to obtain the final shape of components. Forming strategies in SPIF are strongly dependant on the formability of the used metals. Therefore, the optimization of forming parameters requires an understanding of the strain history during the SPIF process. The present paper reports the strain evolution observed by a Digital Image Correlation (DIC) technique in a partial cone with flanges of 50° during SPIF. The results show a bending/reverse bending mechanism when the tool approaches, passes and moves away from a given material point on the tool path. Also the large strains typical for a SPIF process are measured. The paper discusses how to solve some encountered technical problems and presents procedures to obtain reliable strain results during the DIC-SPIF experiment.

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In order to inspect the strength and reliability of structures, measurement by strain gauge is widely used. However, strain gauges measure only the strain of points where they were attached. Therefore, there is a growing demand for reliable and accurate strain distribution measurement of structures. The purpose of this study is to develop a strain distribution measurement system by the digital image correlation (DIC) method. However, the DIC method has several drawbacks concerning accuracy; the out-of-plane deformation of structures has an adverse effect on the measurement accuracy. In this paper, the effect of the out-of-plane deformation was taken into account. We developed a formula to compensate for the effect of the out-of-plane deformation. We carried out experiments using a translation test and a four point bending test to study the accuracy of the strain distribution measurement by the DIC method. The measured strain distributions were compensated by the proposed formula. It was found that the proposed compensation formula is effective to improve the strain distribution measurement by the DIC.

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A non-invasive and three-dimensional strain field identification method is developed in line with the full-field digital image correlation. Three-dimensional images of a soft body are obtained by a multi-slice X-ray CT for both undeformed and deformed states. We employ B-spline functions as the basis of displacement field whose continuity and locality lead to the mathematical simplicity of strain evaluation and the computational efficiency of identification process. The CT images of biological soft tissues are smooth and speckle-less in general, therefore they often induce an indefiniteness of solution. To guarantee the uniqueness of solution, we impose the incompressibility constraint to the displacement field identification by the penalty function method, and minimize the modified objective function of least-square error by the Levenberg-Marquardt method. The minimization yields continuous and smooth fields of displacement and strain. As an experimental example, a heterogeneous compressive strain field within a rubber specimen with granular inclusions is identified to demonstrate the validity of the proposed method. The precision of the identified displacement field is confirmed by comparing with the result of a simple maker-tracing method.

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Recently, the influence of heat conduction has been considered to be a big problem. Hence, the system is developed which corrects an error in the images of the sum of the principal stresses by inverse analysis taking into consideration the influence of the heat conduction. Then, the influence of heat conduction was investigated by the experiment which changed the material, thickness of the specimen and frequency of experiment, hi the case of the analyses of the material of the low heat conductivity, even if it does not take the influence of heat conduction into consideration, a highly precise stress analysis is possible. The stress analyses obtained by infrared thermography at low frequency cyclic load have a large error in metals with high heat conductivity. However, the influence of the heat conduction included in the infrared stress images obtained at high frequency cyclic load can be modified by the inverse analysis of non-steady heat conduction. In this study, we investigated the acrylic resin specimens of the viscoelastic material which is influenced greatly by a frequency change. The optimal frequency for exact principal stresses separation was examined changing the frequency with 4 to 30 Hz by the comparison with the 3-D finite element method. It was found that the optimum frequency of the cyclic load of acrylics material is from 6 Hz to 10 Hz. Moreover, the validity of this approach was discussed paying attention to the hysteretic characteristics as seen in viscoelastic materials, such as acrylic material.

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This paper reports on the experimental technique, based on thermographic measurements, to calculate the thermally induced positioning errors of the ball screw feed drives in machine tools. To compensate a thermal expansion of the ball screw, its temperature must be known with respect to its position, since the local temperature depends on the traversing program. The temperature increases were measured using resistance thermometers at several points of the ball screw. However, to obtain full temperature profile of the ball screw, the field of temperature was measured by infrared camera. Image processing of obtained thermographic snapshots was carried out using software MATLAB. Program enables to calculate temperature and its coordinate along an arbitrarily selected line. Thus the instantaneous temperature profiles along the ball screw are determined. A closed loop FEA was accomplished together with measurement. The programmed loop consists of thermal analysis followed by structural analysis. So the induced axial force is computed. It enables updating of heat sources according to instantaneous structural condition, so the non-steady heat sources in bearings are taken into account.

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In order to evaluate the plastic behaviors of mechanical members, we pay attention to surface temperature that is generated by plastic deformation. The plastic energy exhausted by plastic deforming is largely converted into heat. The generation closely related the plastic deformation. In the present study, the tensile tests were performed on 99% Pure Titanium with a center crack.We measured the surface temperature rise by using the thermocouples and TVS( ThermalVideo System) under the plastic deformation and crack propagation. Furthermore FEM elasto-visco/plastic analysis couples with transient heat conduction analysis was performed. The surface temperature distributions under plastic deformation in FEM simulation good agreed with the experimental ones and the propriety of this non-contact measurement system of macroscopic plastic deformation and fracture process by thermography method was shown.

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Thermoelastic stress analysis is a full-field type stress measuring technique based on the thermoelastic effect of linearly elastic solids. Although adiabatic state is assumed in usual applications of the technique, heat transfer cannot be avoided in practice. In this paper, the effect of heat conduction inside the object on the temperature distribution is considered for plane stress problem. The distributions of the temperature amplitude and phase inside the specimen subjected to sinusoidal load are predicted by boundary element analysis and are measured with a lock-in thermography. It is demonstrated that the numerical and experimental results coincide very well with each other. A discussion on inverse heat conduction analysis for estimating correct stress distribution from measured temperature distribution is given.

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Hot judder is a vibration related phenomenon that occurs due to rapid local heat accumulation, called hot spots, in automobile disk brakes. The hot spots that have steep a temperature gradient make the unequal surface area in the brake disk. As result, causes nonuniform contact between disk and pads; and generates low frequency vibrations called judder. If hot judder causes, it becomes the problem at the safety of the vehicle due to reduction in the braking force into reduction of friction force. Therefore we have to reduce occurrence of judder in the vehicle. In this experimental study, we studied relationship between hot spot temperature and judder vibration. The hot spots temperatures were measured by thermocouples to obtain flow data and location temperature data. Also, a highspeed infrared camera was used to visualize the location of hot spots and observe the heat flow within the disk. Through this experiment process we obtained temperature data by hot spot. We analyzed the mode shape and the heat deformation of disk brake by using the finite element package to correlate heat flow and mode shape. Experiment results show that specific mode shapes of the disk brake are influenced by the generation of hot spots.

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Thermoelastic stress measurement has been getting an increasing attention as a non-destructive evaluation technique for fatigue crack in steel structures. In the thermoelastic stress measurement, stress distribution is measured by lock-in infrared thermography, which correlates temperature change due to the thermoelastic effect with reference-load signal. Load signal from external source, such as load-cell, strain gage or displacement gage, is usually employed as a reference signal in the conventional lock-in technique. In this study, a self-reference lock-in infrared thermography was newly developed, in which a reference signal was constructed by using the same sequential data on thermoelastic temperature change. It enabled us to measure the distribution of relative intensity of applied stress under random loading without using any external load signal. Proposed self-reference lock-in thermography was applied for crack identification based on the detection of the singular stress field in the vicinity of crack tips. Experimental investigations were conducted using welded steel samples. It was found that significant temperature change was observed at the crack tips, demonstrating the feasibility of the proposed technique.

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A new technique was developed for motion compensation in thermoelastic stress measurement. Brindled pattern with different infrared emissivities was applied on the test sample for the motion analysis. Infrared images of the brindled pattern were taken under the same loading condition as the thermoelastic stress measurement. Displacements and deformations on the test sample were analyzed by the digital image correlation method based on the information of the movement of the brindled pattern. Automatic motion compensation was conducted in the subsequent thermoelastic stress measurement based on the results of displacement measurement. Another motion compensation technique without the brindled pattern was proposed, in which visible images were taken by the digital camera as well as the infrared camera. The field of view and the framing sequence of the visible and infrared camera were completely synchronized. The full field displacement measurement was conducted by the digital image correlation method using visible images, then the motion compensation of the infrared images were carried out based on this displacement data. The feasibility of the proposed motion compensation techniques was experimentally demonstrated.

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Moire methods are a versatile suite of techniques for deformation and strain measurement. In particular, it is one of the few methods that readily allow separate determination of the three displacement components. However, since the method still provides displacement components, novel approaches were used to get the derivatives of displacement, i.e strain components. There are two approaches that have been used for this - optical or digital. Optical methods provide high speed visual strain contours but digital methods can give quantitative information. This paper will look at some of the methods developed for strain derivation from moire fringes.

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An improvement of the already proposed phase unwrapping algorithm for directly processing the triangular-typed wrapped phase map of the isochromatic parameter, photoelastically generated by an arccosine function based on the well-known technique of phase-shifting, is presented. In phase unwrapping algorithm, at any pixel, a three-dimensional plane and its normal vector are generated using three fractional (relative) fringe order values. Its generated plane is then adjusted using the orthogonal projection associated with the reference plane. Such point is unwrapped on the basis of regularization. The quality guide map is used to guide phase unwrapping and to mask out the conflictive regions such that they are lastly processed. The circular disk under compression demonstrated the performance of the improved algorithm. Results showed the accuracy improvement in such conflictive regions with reasonable agreement to theory.

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The full-filed evaluation of the isoclinic parameter in digital photoelasticity is presented. The proposed method is based on the four-step color phase shifting technique and the phase unwrapping (PU) algorithm. It is experimentally applied to an eccentrically loaded split ring (C-shaped model). Experimental results shows that the isoclinic-angle map obtained is almost free from the influence of the isochromatic parameter and the isoclinic values lie in the physical interval, -π/2 to +π/2, regardless of the presence of the isotropic point or region.

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