Experimental Method for Tensile Testing of Unidirectional Carbon Fibre Composites Using Improved Specimen Type and Data Analysis.

This paper presents an experimental method for tensile testing of unidirectional carbon fibre composites. It uses a novel combination of a new specimen geometry, protective layer, and a robust data analysis method. The experiments were designed to test and analyze unprotected (with conventional end-tabs) and protected (with continuous end-tabs) carbon fibre composite specimens with three different specimen geometries (straight-sided, butterfly, and X-butterfly). Initial stiffness and strain to failure were determined from second-order polynomial fitted stress-strain curves. A good agreement between back-calculated and measured stress-strain curves is found, on both composite and fibre level. For unprotected carbon composites, the effect of changing specimen geometry from straight-sided to X-butterfly was an increase in strain to failure from 1.31 to 1.44%. The effect of protection on X-butterfly specimens was an increase in strain to failure from 1.44 to 1.53%. For protected X-butterfly specimens, the combined effect of geometry and protection led to a significant improvement in strain to failure of 17% compared to unprotected straight-sided specimens. The observed increasing trend in the measured strain to failure, by changing specimen geometry and protection, suggests that the actual strain to failure of unidirectional carbon composites is getting closer to be realized.

Comparison of the positive rate of microbiological examination in different clinical specimens / 中国基层医药

Objective@#To compare the positive rate of microbiological examination in different clinical specimens, and to provide reliable basis for improving the quality of microbiological examination and management of nosocomial infection.@*Methods@#A total of 2 028 bacterial culture specimens were collected from the hospitalized patients in the Second People's Hospital of Jinanfrom March 2016 to February 2018.The samples were examined by Micro Scan autoSCAN4 automatic bacteriological identification analyzer.Strictly according to the specification of the standard operation, the positive rates of microbial testingof all kinds of clinical specimens were statistically analyzed.@*Results@#The positive rate of microbiological examination in 2 028 clinical specimens was 44.33%.The positive rate of microbiological examination in sputum was the highest(58.96%), followed by ophthalmic secretion(40.64%), eye contents(37.96%), urine(34.55%), blood(21.11%).@*Conclusion@#The positive rate of microbiological examination is different in different clinical specimens.The epidemiological situation of nosocomial infection can be understood by analyzing the microbiological examination of different clinical specimens in clinic.In order to provide a reliable basis for clinical prevention and treatment of nosocomial infection, and to further improve the positive rate of clinical microbiological examination, we should actively carry out improvement countermeasures against its influencing factors.

Behaviour of Corroded Single Stud Shear Connectors.

In this study, the effect of corrosion on the static behavior of stud shear connectors was investigated. An innovative test setup for single stud shear connectors was designed and established. Two series of specimens having different stud diameters were fabricated and tested. The test specimens were firstly corroded to different corrosion rates by the electronic accelerating method. Static loading tests were then performed to obtain the load-slip curves and ultimate strengths of the corroded test specimens. The actual corrosion rates were measured from the studs obtained from the tested specimens. The test results were compared with the push out test specimens having similar corrosion rates. It is shown that the test results obtained from the single stud shear connectors are conservative compared with the corroded push test specimens, which prove the validation of the single stud shear connector test method. The effect of corrosion on the behavior of stud shear connectors was also presented.

The Preˉanalytical Quality Control of Specimen in Clinical Laboratory / 国际检验医学杂志

Objective To explore the methods and mesures for the pre-analytical quality control of test specimen and to improve the accuracy and reliability of test results.Methods According to the relevant requirements of IS015189,various measures for the specimen circulation process and collection technology two aspects were taken to control the full links of clinical specimen collection and transport,and the incidence of unqualified specimen before and after the improvements were analyzed.Results After the imple-mentation of the improvement measures,the incidence of unqualified specimens was decreased significantly.Conclusion Implemen-tation of the whole aspect of pre-analytical quality control can effectively improve the quality of specimen in order to improve the test quality.

An Isoparametric Finite Element Model for Large-Strain Elastostatics.

This paper describes a simple finite element model for large-strain elastostatics. The realization of the model in a small-scale computer-code is described. The purpose of the model is to produce test problems for research on the application of penalty techniques in nonlinear elasticity. For this reason the code must balance the requirements of reasonable flexibility with those of computational economy. The current code employs multilinear isoparametric elements. The model is capable of generalization to a variety of element types. The solution method employed is that of incremental loading combined with the Newton-Raphson method. Symmetric, banded systems of equations are produced which are solved in-core. Two- and three-dimensional symmetric bodies which are isoparametric images of a reference "brick" may be modeled. An example comparing two- and three-dimensional models of a "dogbone"-shaped A.S.T.M. rubber tensile-test specimen is presented. The results shed some light on the nature of stress-concentrations which occur in specimens of this geometry.