• Tribology and Lubricants
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• v.11 no.5
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• pp.99-107
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• 1995

This paper reported research results to develop an algorithm of on-lin evaluation of surface profiles and roughness generated by turning. The developed module consisted of computer simulation of surface profiles using mechanism of cutting mark formation and cutting vibrations, and online measurement of cutting vibrations. The relative cutting vibrations between tool and worpkiece were measured through an inductance pickup at the rate of one sample per rotation of the workpiece. The sampling process was monitored using an encoder to avoid conceling out the phase lag between waves. The digital cutting signals from the Analog-to-Digital converter were transferred to the simulation module of surface profile where the surface profiles were generated. The developed algorithm or surface generation in a hard turning was analyzed through computer simulations to consider the stochastic and dynamic nature of cutting process. Cutting tests were performed using AISI 304 Stainless Steel and carbide inserts in practical range of cutting conditions. Experimental results showed good correlation between the surface profiles and roughness obtained using the developed algorithm and the surface texture measured using a surface profilemeter. The research provided the feasibility to monitor surface characteristics during tribelogical tests considering wear effect on surface texture in machining.

• International Journal of Precision Engineering and Manufacturing
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• v.8 no.2
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• pp.20-25
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• 2007

This paper describes a second-generation dual sine-grid surface encoder for 2-D position measurements. The surface encoder consisted of a 2-D grid with a 2-D sinusoidal pattern on its surface, and a 2-D angle sensor that detected the 2-D profile of the surface grid The 2-D angle sensor design of previously developed first-generation surface encoders was based on geometric optics. To improve the resolution of the surface encoder, we fabricated a 2-D sine-grid with a pitch of $10{\mu}m$. We also established a new optical model for the second-generation surface encoder that utilizes diffraction and interference to generate its measured values. The 2-D sine-grid was fabricated on a workpiece by an ultra precision lathe with the assistance of a fast tool servo. We then performed a UV-casting process to imprint the sine-grid on a transparent plastic film and constructed an experimental setup to realize the second-generation surface encoder. We conducted tests that demonstrated the feasibility of the proposed surface encoder model.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.1
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• pp.78-83
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• 2010

This paper discusses the surface roughness of corroded reinforcement rebar in reinforced concrete structures focusing on the quantitative measurement technique for rebar corrosion. Reinforcement rebar was corroded using accelerated corrosion induced method and corrosion rates were 0%, 1%, 2%, 3%, 5%, and 10% of mass losses. Using 3-dimensional scanner each surface profile of reinforcement rebar was established, and surface roughness was measured. Through tests and analyses of corroded reinforcement rebar, the following topics were particularly discussed: measurement of surface roughness, relationship between area and surface roughness, relationship between surface roughness and bond performance. As a result, surface roughness of corroded rebar was found to be very effective to bond strength until 2% of corrosion rate. It was also discussed how to relate surface roughness of corroded rebar to bond strength of reinforced concrete structures.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.499-505
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• 2021

The purpose of this study is to investigate experimentally the physical/chemical properties of concrete surface according to types of formworks. Plywood formwork and coated plywood formwork were prepared. In addition, plywood formwork with sand paper was prepared to simulate deterioration of concrete or rough surface of concrete. Normal concrete was used in this study. The properties of concrete surface were investigated by visual inspection, scanning electron microscopy and energy-dispersive X-ray spectroscopy techniques, elemental mapping, 2D and 3D surface profile measurement, and zeta potential measurement. Test results showed that concrete in a coated formwork had smooth surface and concrete in the formwork with sand paper had rough surface. It was observed that properties of concrete surface depended on types of formworks. Furthermore, differences in surface roughness were significantly higher than those in chemical compositions and zeta potential.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.21-28
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• 2008

Fizeau interferometer is used for inspecting the lens surface profile accurately. This study is focused on the design and optical measuring techniques for large optical components, such as a reflection mirror for large area lithography or astronomical purpose. A tower type Fizeau interferometer is designed and set up in horizontally with a 45$^{\circ}$ fold mirror which makes easy to align the optical path of heavy interferometer system. To align the optical path, a five-axes stage for the interferometer is required. This study shows a method of the 45$^{\circ}$ fold mirror alignment by using a three-axis stage instead of adjusting the interferometer itself or measuring object. This system will be installed on the large optics polishing machine during the manufacturing process as an on-machine inspection system.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.3
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• pp.448-453
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• 1998

An inverted, stagnation point flow OMVPE reactor was studied by laser Raman spectroscopy. Pure rotational Raman scattering by the carrier gas $(N_2; or; H_2)$ was used to determine the axial centerline temperature profile in the reactor as a function of the inlet flow velocity and the rector aspect ratio. A larger temperature gradient normal to the susceptor surface was obtained with higher gas glow velocity, larger aspect ratio, and the use of a $N_2$ carrier gas.

• KSTLE International Journal
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• v.6 no.1
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• pp.21-27
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• 2005

A technique for a wear volume calculation is improved and verified in this research. The wear profile data measured by a surface roughness tester is used. The present technique uses a data flattening, the FFT and the windowing procedure, which is used for a general signal processing. The measured value of an average roughness of an unworn surfnce is used for the baseline of the integration for the volume calculation. The improvements from the previous technique are the procedures of the data flattening and the determination of a baseline. It is found that the flattening procedure efnciently manipulates the raw data when the levels of it are not horizontal, which enables us to calculate the volume reasonably well and readily. By comparing it with the weight loss method by using artificial dents, the present method reveals more volume by aroung 3~10%. It is attributed to the protruded region of the specimen and the inaccuracy and data averaging during the weght loss measurement. From a thorough investigation, it is concluded that the present technique can provide an accurate wear volume.

• Proceedings of the KSME Conference
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• 2000.11a
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• pp.470-474
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• 2000

Cold expansion of fastener holes is a mechanical process widely used in the aerospace industry. This treatment leads to an improvement of fatigue behavior due to the developed compressive residual stresses on the hole surface. The residual stress profile depends on the parameters of cold expansion, which are, expanding rate, inserting direction of mandrel, material properties etc. and the method to confirm this profile is only measurement by X-ray diffractometer. Despite its importance to aerospace industries, little attention has been devoted to the accurate modelling of the process. In this paper, Two-dimensional axisymmetric finite element simulations have been conducted for the cold expansion in an aluminium plate in order to predict the magnitude and distribution of the residual stress and plastic deformation. Maximum compressive residual stress could be increase about 7 percent using the 2-step cold expansion method.

• Journal of Welding and Joining
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• v.30 no.6
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• pp.74-79
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• 2012

It depends on the joint configuration, dimensions and constraints of the joint whether the residual stress at the root of single-sided butt weld is tensile or not. Therefore, recommendation is generally made that high R ratio should be used in the fatigue test of welded joint in order to prevent excessively long life caused by compressive residual stress. In this research, the residual stress profile in butt weld joint was obtained through compliance method, using successive extension of a slot and measurement of the variation of strain during the slot extension. The residual stress profile was firstly assumed to be the linear summation of Legendre polynomials up to 9th order excluding 0th and 1st order. Strain variation on the surface was measured while the slot was being extended by cutting to find out the 8 unknown coefficients of each polynomial term. The cut was made by the electric discharge machine. It was concluded that the residual stress near the surface is positive valued, however, it turned into the negative value as soon as it passed through 2 or 3 mm of the depth.

• Journal of Ocean Engineering and Technology
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• v.22 no.5
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• pp.44-51
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• 2008

The planning and design of coastal structures against wave attack is required to accurately predict wave transformation, wave run-up, and fluid. particlevelocities an a slope. On tire other hand, in tire swash and surf zones of a natural beach, where coastal erosion and accretion occur at tire land-sea boundary, hydrodynamic analysis is essential. In this study, a RBREAK2 numerical model was created based on the nonlinear shallow water equation and laboratory measurements were carried out in terms of tire free surface elevations and velocities for tire cases of regular and irregular waves on 1 : 10 and 1 : 5 impermeable slopes. The data were used to evaluate tire applicability and limitations of tire RBREAK2 numerical model. The numerical mode1 could predict tire cross-shore variation of the wave profile reasonably well, but showed more accurate results for slopes that were steeper than 1 : 10. Except near tire wave crest, tire computed depth averaged velocities could represent tire measured profile below tire trough level fairly well.