► We measured flat and spherical samples. ► We used stylus profilometer, infinite focus and confocal laser scanning microscopes. ► We obtained the mathematical models of Ra and Rz roughness ...parameters.
The quantitative determination of surface roughness is of vital importance in the field of precision engineering. This paper presents an experimental study of the roughness analyses for the flat and spherical surfaces of machined metal in order to compare the roughness data taken from the cloud data produced by the stylus type profilometer and two optical-based measurement instruments, namely the infinite focus microscope and the confocal laser scanning microscope.
In this experimental study, the roughness measurements for fifteen flat and six spherical surfaces were repeated six times using three different measurement instruments. Great care was paid to measure the same location for each measurement. For the comparison of the measurement techniques, the same measurement process was applied to the flat and spherical surfaces individually, and the configurations of the measurement instruments (filter type, cut-off, resolution etc.) were synchronized.
R
a
, two-dimensional (2D) roughness parameter and
S
a
, three-dimensional (3D) roughness parameter were also compared. The measurement results for the samples having spherical surfaces indicated a considerably high difference in values taken from the stylus profilometer and two optical-based measurement instruments in contrast to those for flat surfaces.
A scoring system combining clinical history and simple ultrasound parameters was developed to predict early pregnancy viability beyond the first trimester. The scoring system has not yet been ...externally validated. This study aimed to externally validate this scoring system to predict ongoing pregnancy viability beyond the first trimester.
This prospective observational cohort study enrolled women with singleton intrauterine pregnancies before 12 weeks of gestation. Women underwent examination and ultrasound scan to assess gestational sac size, yolk sac size, and fetal pulsation status. A pregnancy-specific viability score was derived in accordance with the Bottomley score. Pregnancy outcomes at 13 to 16 weeks were documented. Receiver-operating characteristic curve analysis was used to assess the discriminatory performance of the scoring system.
In total, 1508 women were enrolled; 1271 were eligible for analysis. After adjustment for covariates, miscarriage (13%) was significantly associated with age ≥35 years (odds ratio OR=1.99, 95% confidence interval CI: 1.19-3.34), higher bleeding score (OR=2.34, 95% CI: 1.25-4.38), gestational age (OR=1.17, 95% CI: 1.13-1.22), absence of yolk sac (OR=4.73, 95% CI: 2.11-10.62), absence of fetal heart pulsation (OR=3.57, 95% CI: 1.87-6.84), mean yolk sac size (OR=1.25, 95% CI: 1.06-1.47), and fetal size (OR=0.82, 95% CI: 0.77-0.88). The area under the receiver operating characteristic curve was 0.91 (95% CI: 0.89-0.93). Viability score of ≥1 corresponded to a >90% probability of viable pregnancy.
The scoring system was easy to use. A score of ≥1 could be used to counsel women who have a high likelihood of viable pregnancy beyond the first trimester.
The importance of computer-aided measurement techniques as a means of controlling industrial manufacturing and testing technical products with high accuracy increases ever more with the general goal ...of improving the quality of all kinds of products. This development started about 20 years ago and is still improving. Especially, computer-aided co-ordinate metrology is a very important and universal tool for solving complex measuring tasks for workpiece metrology.
This paper introduces the application of statistical analysis of workpiece geometry measurement results regarding the recently developed so-called “Skin-Model”. The “Skin-Model” presents a new ...description for Geometrical Product Specification and Verification (GPS) with its associated details and on its basis every workpiece can be geometrically defined and considered by applying manipulations of the workpiece geometry. This determination is based on mathematical rules and definitions. It means that according to this determination every workpiece can be designed and on the other hand according to the design it can be measured very clearly. This model enables the complete implementation of Geometrical Product Specification and Verification (GPS) into Coordinate Measuring Techniques (CMT) and vice versa. As part of this implementation the software KOORMESS which was developed for transformation of measuring result is also integrated in this project. Selected series of workpieces from industrial manufacturers were measured in the precision measuring laboratory. Based on the measurement results gained it was possible to carry out extensive evaluations by using statistical methods e.g. correlation analysis. As result of the research project, conclusions can be drawn about the correlation between different geometrical deviations and the manufacturing conditions with the overall goal to achieve lower costs and higher quality in production.
Innershell Absorption Spectroscopy of Amino Acids Kaznacheyev, K; Osanna, A; Jacobsen, C ...
The journal of physical chemistry. A, Molecules, spectroscopy, kinetics, environment, & general theory,
04/2002, Letnik:
106, Številka:
13
Journal Article
Recenzirano
We present comprehensive measurements of the C (carbon) K edge near-edge X-ray absorption (NEXAFS) spectra of all 20 amino acids commonly occurring in nature. Qualitative trends among the spectra of ...amino acids with similar chemical character are identified and spectral features are compared with extensive ab initio calculations. The contributions of individual units and substitutional groups have been determined to explore their fingerprinting character using the building block concept. Several such units are found. Two that give particularly clear features in the C 1s NEXAFS spectra are the carboxyl group (which can be clearly identified by a pronounced structure due to the C 1s→π*C O transition with maximum at 288.65(5) eV) and modified phenol rings in aromatic amino acids (which give sharp C 1s→π*C C structures). The latter transitions are located around 285 eV, and their shape is specific for each aromatic amino acid. Other building blocks, such as the CNH n group and the CH, CC, CO, CN pair bonds, are also identified, although their characteristic features are less pronounced in the C K edge spectra than the carboxylic and aromatic structures. This study provides the basis for rigorous assignment of the NEXAFS spectra of the amino acids, and will be helpful in developing X-ray absorption spectroscopy for quantitative analysis of proteins.
The tolerances of workpieces decrease continuously since the beginning of the twentieth century. This lies in one line with the perspective of nanotechnology and also recent reports give evidence on ...the effect of constantly tightening workpiece tolerances. As tolerances of workpieces decrease the interaction between dimensional tolerances and surface finish becomes more important. In this study ideas of the authors to use the Abbott curve for specification of surface finish are presented and a proposal is given how to specify it in engineenng drawings.
The importance of computer aided measurement techniques as a means of controlling industrial manufacturing and testing technical products with high accuracy increases ever more with the general goal ...of improving the quality of all kinds of products. This development started about twenty years ago and is still improving. Especially computer aided co-ordinate metrology is a very important and universal tool for solving complex measuring tasks for workpiece metrology. This measurement technique can also be applied to evaluate the shape of non technical structures, for example, human limbs or joints with high accuracy. The results of such measurements provide the basis for the improvement and optimization of future work in endo prosthesis.
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