scholarly journals On-Machine Precision Form Truing and In-Situ Measurement of Resin-Bonded Spherical Diamond Wheel

2020 ◽  
Vol 10 (4) ◽  
pp. 1483 ◽  
Author(s):  
Jinhu Wang ◽  
Qingliang Zhao ◽  
Chunyu Zhang ◽  
Bing Guo ◽  
Julong Yuan
Keyword(s):  
Surface Profile ◽  
Ground Surface ◽  
Diamond Wheel ◽  
In Situ Measurement ◽  
Coarse Grained ◽  
Alignment Error ◽  
Machine Precision ◽  
Form Accuracy ◽  
Measurement Results

The resin-bonded spherical diamond wheel is widely used in arc envelope grinding, where the demands for form accuracy are high and the form truing process is challenging. In this paper, on-machine precision form truing of the resin-bonded spherical diamond wheel is accomplished by using a coarse-grained diamond roller, and in-situ measurement of the form-truing error is conducted through a laser scan micrometer. Firstly, a novel biarc curve-fitting method is proposed based on the in-situ measurement results to calculate the alignment error between the diamond roller and the spherical diamond wheel. Then, on-machine precision form truing of a D46 resin-bonded spherical diamond wheel is completed after alignment error compensation. The in-situ measurement results show that the low-frequency form-truing error is approximately 5 μm. In addition, the actual form-trued diamond wheel has been employed in grinding a test specimen, and the resulting form accuracy is approximately 1.6 μm without any compensation. The ground surface profile shared similar characteristics with the roller-trued diamond wheel profile, confirming that the diamond roller truing and in-situ measurements methods are accurate and feasible.

Polishing Characteristics of ELID-Ground Surface of Nano Precision Optical Elements

2005 ◽  
Vol 291-292 ◽  
pp. 365-370 ◽  
Author(s):  
Wei Min Lin ◽  
Hitoshi Ohmori ◽  
T. Suzuki ◽  
Yoshihiro Uehara ◽  
Shinya MORITA
Keyword(s):  
Ground Surface ◽  
Diamond Wheel ◽  
Fused Silica ◽  
Optical Elements ◽  
Form Accuracy ◽  
High Form ◽  
Ultra Precision ◽  
Fundamental Research ◽  
Aspherical Mirrors ◽  
Polishing Tool

This paper describes an ultra precision polishing method of aspherical mirrors, and the fundamental research on polishing characteristics. The aspherical mirrors with a diameter of about 30mm made by fused silica glass and CVD-SiC were ELID (electrolytic in-process dressing)-ground to high form accuracy with #4000 cast iron bonded diamond wheel, and then polished with a small polishing tool. As the result, final surface roughness of 1.4nmRa and form accuracy of 1.2 μm was obtained.

scholarly journals Displacement Calculation Method on Front Wall of Covered Sheet-Pile Wharf

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Wen-xue Gong ◽  
Li-yan Wang ◽  
Jinsong Li ◽  
Bing-hui Wang
Keyword(s):  
Earth Pressure ◽  
In Situ Measurement ◽  
Front Wall ◽  
Surface Boundary ◽  
Sheet Pile ◽  
Soil Arching ◽  
Theoretical Derivation ◽  
Measurement Results ◽  
Stress And Deformation

Covered sheet-pile wharves are widely used in port engineering, water conservancy, and civil engineering. This paper is based on the theory of earth pressure and the soil arching effect. According to the stress and deformation characteristics of the covered sheet-pile wharf, the formulas used to calculate the force and deformation of the front wall of a covered sheet-pile wharf under static loads are deduced. The accuracy of the theoretical derivation is verified by comparing actual measured stress and deformation data of Jingtang Port 32#. The comparison shows that when calculating the displacement of the section below the mud surface boundary, the results are in agreement with the in situ data. However, when calculating the displacement of the section above the mud surface boundary, if the anchorage point displacement is ignored because the anchorage point displacement is limited artificially, the calculated tension of the tie rod is relatively large. This leads to a significant decrease in the calculation result of the section above the mud surface boundary, which is very different from actual in situ measurement results. If anchorage point displacement is considered, the calculated tension of the tie rod is more accurate, and the calculation results of the front wall displacement are very close to in situ measurement results because the anchorage point displacement is assumed scientifically.

scholarly journals Tropospheric HONO distribution and chemistry in the southeastern US

2018 ◽  
Vol 18 (12) ◽  
pp. 9107-9120 ◽  
Author(s):  
Chunxiang Ye ◽  
Xianliang Zhou ◽  
Dennis Pu ◽  
Jochen Stutz ◽  
James Festa ◽  
...  
Keyword(s):  
Nitrous Acid ◽  
Ground Surface ◽  
Southeastern Us ◽  
Upper Limit ◽  
Measurement Results ◽  
Research Aircraft ◽  
Urban Plumes ◽  
Air Column ◽  
Background Area

Abstract. Here we report the measurement results of nitrous acid (HONO) and a suite of relevant parameters on the NCAR C-130 research aircraft in the southeastern US during the NOMADSS 2013 summer field study. The daytime HONO concentration ranged from low parts per trillion by volume (pptv) in the free troposphere (FT) to mostly within 5–15 pptv in the background planetary boundary layer (PBL). There was no discernible vertical HONO gradient above the lower flight altitude of 300 m in the PBL, and the transport of ground surface HONO was not found to be a significant contributor to the tropospheric HONO budget. The total in situ HONO source mean (±1 SD) was calculated as 53 (±21) pptv h−1 during the day. The upper-limit contribution from NOx-related reactions was 10 (±5) pptv h−1, and the contribution from photolysis of particulate nitrate (pNO3) was 38 (±23) pptv h−1, based on the measured pNO3 concentrations and the median pNO3 photolysis rate constant of 2.0 × 10−4 s−1 determined in the laboratory using ambient aerosol samples. The photolysis of HONO contributed to less than 10 % of the primary OH source. However, a recycling NOx source via pNO3 photolysis was equivalent to ∼ 2.3 × 10−6 mol m−2 h−1 in the air column within the PBL, a considerable supplementary NOx source in the low-NOx background area. Up to several tens of parts per trillion by volume of HONO were observed in power plant and urban plumes during the day, mostly produced in situ from precursors including NOx and pNO3. Finally, there was no observable accumulation of HONO in the nocturnal residual layer and the nocturnal FT in the background southeastern US, with an increase in the HONO ∕ NOx ratio of ≤ 3 × 10−4 h−1 after sunset.

scholarly journals Measurements of thermal Transmittance of an External massive timber wall in-situ and in the Laboratory

2020 ◽  
Vol 172 ◽  
pp. 14009
Author(s):  
Christoph Geyer ◽  
Andreas Müller ◽  
Barbara Wehle
Keyword(s):  
In Situ Measurement ◽  
Test Results ◽  
Mean Values ◽  
Thermal Transmittance ◽  
University Of Applied Sciences ◽  
Measurement Results ◽  
State Boundary ◽  
U Value ◽  
Massive Timber

The thermal transmittance of an exterior massive timber wall was measured in situ in Appenzell, Switzerland according to the standard ISO 9869-1. The measurements were performed with two different measurement sets in parallel. The measurements started in February and stopped at end of April. The measuring data were analyzed using mean values of the thermal transmittance coefficient and of the thermal resistance following the procedure of ISO 9869-1. In order to clarify if the in-situ measurement results show significant deviations from the measurement results of the thermal transmittance obtained in the laboratory, the thermal transmittance of the identical wall construction was measured in the laboratory of Bern University of Applied Sciences in Biel according to the standard EN ISO 8990 for steady state boundary conditions in a guarded and calibrated hot box. The test results will be presented and the measurement setup will be described. The calculation value of the thermal transmittance coefficient of the massive timber wall according to EN ISO 6946 is U = 0.53 W/(m2K). The test results of the thermal transmittance coefficient, U-value of the wall, measured in the hot box, agreed well within a confidence level of 95 % with the calculated value. The in-situ measurement results of the thermal transmittance coefficient of the two measurement sets differ significantly in the order of 8 % referred to the calculated U-value of the wall as the basic amount. Furthermore, both in situ test results of the U-value of the wall show significant deviations from the calculated U-value up to 27 %.

scholarly journals Optimization of Nano-Topography Distribution by Compensation Grinding

2022 ◽  
Vol 16 (1) ◽  
pp. 32-37
Author(s):  
Nobuhito Yoshihara ◽  
◽  
Masahiro Mizuno
Keyword(s):  
Spatial Frequency ◽  
Ground Surface ◽  
View Point ◽  
Form Error ◽  
Form Accuracy ◽  
Optical Surfaces ◽  
High Form ◽  
Compensation Methods ◽  
Measurement Results ◽  
Grinding Conditions

Optical surfaces are required to have high form accuracy and smoothness. The form accuracy must be below 50 nm. Form accuracy is currently on the order of several tens of nanometers or less; however, further improvement is required. To improve form accuracy, compensation grinding is performed based on form measurement results. However, when the form error is small, a small periodical waviness occurs on the ground surface, which is known as nano-topography. This waviness cannot be compensated for using conventional compensation methods because the nano-topography distributions are not reproducible. A previous study showed that grinding conditions affect the spatial frequency of nano-topography. Therefore, in this study, optimum grinding conditions are estimated from the view point of nano-topography distributions, and the grinding conditions are compensated to optimize these distributions.

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