Journal articles: 'Test specimens'

1

Bahadir, Fatih, and Fatih Süleyman Balik. "Seismic Performance Improvement of 3D Reinforced Concrete Frames with Different Strengthening Applications." Applied Mechanics and Materials 789-790 (September 2015): 1140–44. http://dx.doi.org/10.4028/www.scientific.net/amm.789-790.1140.

Full text

Abstract:

This study used test frames were purposely detailed and constructed with observed deficiencies in investigated dormitory buildings of Turkey. In this study, four reinforced concrete frames were produced two storeys, one bay and 3D in 1/6 geometric scale was tested. Since the studied frame was the external frame of the structure, brick infill wall with a window opening was also included. The first specimen was the reference specimen and contained no strengthening and no brick wall. The second specimen was contained brick wall. The third specimen was strengthened with internal steel panel. Finally fourth specimen’s was strengthened with infilled RC shear wall. The test specimens were subjected to reversed cyclic quasi-static lateral loading. Strength of the test specimens were measured and compared. Test results indicated that the strengthened specimens displayed significantly higher lateral strength than the reference specimen considerably.

APA, Harvard, Vancouver, ISO, and other styles

2

Deng, Jun. "Test Methods for Mechanical Properties of Structural Adhesives." Advanced Materials Research 97-101 (March 2010): 814–17. http://dx.doi.org/10.4028/www.scientific.net/amr.97-101.814.

Full text

Abstract:

One of the greatest drawbacks to predicting the behaviour of bonded joints has been the lack of reliable data on the mechanical properties of adhesives. In this study, methods for determining mechanical properties of structural adhesive were discussed. The Young’s modulus, Poisson’s ratio and tensile strength of the adhesive were tested by dogbone specimens (bulk form) and butt joint specimens (in situ form). The shear modulus and shear strength were test by V-notched specimens (bulk form) and thick adherend lap-shear (TALS) joint specimens (in situ form). The test results show that the elastic modulus provided by the manufacturer is too low, the dogbone specimen is better than the butt joint specimen to test the tensile strength and elastic modulus and the TALS joint specimen is better than the V-notched specimen to test the shear strength.

APA, Harvard, Vancouver, ISO, and other styles

3

Komorek, Andrzej, Jan Godzimirski, and Marek Rośkowicz. "Analysis of a New Shape of Test Specimen for Block Shear Impact Test." Materials 13, no. 7 (April 4, 2020): 1693. http://dx.doi.org/10.3390/ma13071693.

Full text

Abstract:

This paper reports and discusses an experimental comparison of metal specimens for impact strength research of adhesive connections with different shapes of the upper element. The top element of the specimen of the cuboid shape was replaced with a disc-shaped element. The experimental investigations were supplemented with dynamic numerical calculations of the tested cases. The results of the experimental studies indicate that the material applied to the produce of the top element of the block specimen deformed plastically as a result of applying the load, which further hinders the interpretation of already problematic investigation results. The numerical analysis confirms exceeding the yield point, by stresses, of the material that the specimen elements were made of. Modified specimens were characterized by only little greater repeatability of test results and greater impact strength caused by plastic deformations of the cylindrical specimen element.

APA, Harvard, Vancouver, ISO, and other styles

4

Parvez, Mohammad Masud, Yitao Chen, Sreekar Karnati, Connor Coward, Joseph W. Newkirk, and Frank Liou. "A Displacement Controlled Fatigue Test Method for Additively Manufactured Materials." Applied Sciences 9, no. 16 (August 7, 2019): 3226. http://dx.doi.org/10.3390/app9163226.

Full text

Abstract:

A novel adaptive displacement-controlled test setup was developed for fatigue testing on mini specimens. In property characterization of additive manufacturing materials, mini specimens are preferred due to the specimen preparation, and manufacturing cost but mini specimens demonstrate higher fatigue strength than standard specimens due to the lower probability of material defects resulting in fatigue. In this study, a dual gauge section Krouse type mini specimen was designed to conduct fatigue tests on additively manufactured materials. The large surface area of the specimen with a constant stress distribution and increased control volume as the gauge section may capture all different types of surface and microstructural defects of the material. A fully reversed bending (R = −1) fatigue test was performed on simply supported specimens. In the displacement-controlled mechanism, the variation in the control signal during the test due to the stiffness variation of the specimen provides a unique insight into identifying the nucleation and propagation phase. The fatigue performance of the wrought 304 and additively manufactured 304L stainless steel was compared applying a control signal monitoring (CSM) method. The test results and analyses validate the design of the specimen and the effective implementation of the test bench in fatigue testing of additively manufactured materials.

APA, Harvard, Vancouver, ISO, and other styles

5

Mughal, Z., E. Luff, O. Okonkwo, and C. E. J. Hall. "Test, test, test – a complication of testing for coronavirus disease 2019 with nasal swabs." Journal of Laryngology & Otology 134, no. 7 (July 2020): 646–49. http://dx.doi.org/10.1017/s0022215120001425.

Full text

Abstract:

AbstractBackgroundCoronavirus disease 2019, a highly transmissible respiratory infection, has created a public health crisis of global magnitude. The mainstay of diagnostic testing for coronavirus disease 2019 is molecular polymerase chain reaction testing of a respiratory specimen, obtained with a viral swab. As the incidence of new cases of coronavirus disease 2019 increases exponentially, the use of viral swabs to collect nasopharyngeal specimens is anticipated to increase drastically.Case reportThis paper draws attention to a complication of viral swab testing in the nasopharynx and describes the premature engagement of a viral swab breakpoint, resulting in impaction in the nasal cavity.ConclusionThis case highlights a possible design flaw of the viral swab when used to collect nasopharyngeal specimens, which then requires an aerosol-generating procedure in a high-risk patient to be performed. The paper outlines a safe technique of nasal foreign body removal in a suspected coronavirus disease 2019 patient and suggests alternative testing materials.

APA, Harvard, Vancouver, ISO, and other styles

6

Yeoh, O. H. "Some Geometric Considerations for Rubber—Metal Bond Test Specimens." Rubber Chemistry and Technology 79, no. 2 (May 1, 2006): 320–37. http://dx.doi.org/10.5254/1.3547940.

Full text

Abstract:

Abstract Most methods for predicting fatigue lives of rubber components rely heavily on experimental studies that involve specimens subjected to essentially uniform states of deformation. But, in service, rubber components often fail at or near rubber-metal bonds where the state of deformation is far from uniform. Before experimental studies of fatigue failure in the vicinity of rubber-metal bonds, it is prudent to perform an analysis of the specimen geometry to make sure it has been optimized. This paper reports on finite element analyses of cylindrical rubber-metal bond test specimens recommended in ASTM D 429. The results suggest that taller specimens (height/radius ratio ≥ 2) have some advantages. Interpretation in terms of the strain energy release rate is recommended. A new asymmetric test specimen is proposed.

APA, Harvard, Vancouver, ISO, and other styles

7

Mizuno, Satoshi, Toshifumi Kakiuchi, and Yoshihiko Uematsu. "Fatigue Test of Small Sized AZ31 Magnesium Alloy Using Micropillar Specimen." Key Engineering Materials 525-526 (November 2012): 165–68. http://dx.doi.org/10.4028/www.scientific.net/kem.525-526.165.

Full text

Abstract:

The bending fatigue tests were performed using the small sized specimens of AZ31 magnesium alloy fabricated by the focused ion beam (FIB) processing to investigate the scale effect on the fatigue behavior. For the fatigue test of the small sized specimens, the fatigue testing apparatus was constructed by the piezo actuator and the high-resolution microscope for controlling the very small displacement. The specimen was micropillar-shaped with the rectangular cross section of 3μm x 8μm and the height of 40μm. The fatigue strengths of the small sized specimens were higher than those of the bulk sized specimens. The fracture surfaces were also investigated carefully compared with those of the bulk specimen.

APA, Harvard, Vancouver, ISO, and other styles

8

Tiernan, Peter, and Alan Hannon. "Optimisation of Cruciform Test Specimen for Biaxial Tensile Testing of Sheet Metal." Advanced Materials Research 264-265 (June 2011): 114–22. http://dx.doi.org/10.4028/www.scientific.net/amr.264-265.114.

Full text

Abstract:

One of the most restricting aspects of the biaxial tensile test for sheet metal is the design of the cruciform specimen. Although specimens of the cruciform type have previoussly been investigated quite extensively, no standard geometry for the cruciform specimen exists. Using a specifically designed pantograph apparatus for operation in a standard tensile testing machine, various cruciform specimens were analysed experimentally. Finite element modelling of the specimens was also conducted to establish optimum specimen geometry. Through a process of optimisation, a standard cruciform specimen was designed which can be used to accurately predict the mechanical behaviour of cold rolled low-carbon steel when formed in multiple directions simultaneously.

APA, Harvard, Vancouver, ISO, and other styles

9

Karcher, Donald S., and Christopher M. Lehman. "Clinical Consequences of Specimen Rejection: A College of American Pathologists Q-Probes Analysis of 78 Clinical Laboratories." Archives of Pathology & Laboratory Medicine 138, no. 8 (August 1, 2014): 1003–8. http://dx.doi.org/10.5858/arpa.2013-0331-cp.

Full text

Abstract:

Context.—Clinical laboratory specimens may be rejected as unsuitable for analysis for a variety of reasons and specimen rejection may have significant clinical consequences. Objective.—To quantify the clinical consequences of specimen rejection and determine the impact of laboratories' policies and practices on these consequences. Design.—Participants prospectively reviewed consecutive blood and urine specimens submitted to the chemistry and/or hematology laboratories to identify rejected specimens. For each rejected specimen, the patient's age, specimen type, testing priority, rejection reason, time from specimen receipt to receipt of recollected/relabeled specimen, recollection method, and test result time were recorded. Specimen/test abandonment was determined by failure to recollect or relabel a rejected specimen. Each laboratory's policy regarding relabeling of incorrectly labeled specimens was recorded, along with how many relabeled specimens were subsequently discovered to be mislabeled. Results.—Specimen rejection led to a (1) high rate of specimen recollection, (2) delay in result availability (median of 65 minutes), and (3) high rate of specimen/test abandonment. Longer test result delay was associated with higher hospital bed size; and higher test abandonment rate, with failure of the laboratory to request specimen recollection. Relabeling of incorrectly labeled specimens was found to be of little benefit and was associated with a substantial percentage of subsequently mislabeled specimens. Conclusion.—Specimen rejection has significant clinical consequences, including patient discomfort, significant delay in result availability, and high rate of specimen/test abandonment. Allowing routine relabeling of incorrectly labeled specimens is a dangerous practice, with little measureable benefit and with an increased risk to patient safety.

APA, Harvard, Vancouver, ISO, and other styles

10

Muraya, P. M. "Homogeneous test specimens from gyratory compaction." International Journal of Pavement Engineering 8, no. 3 (September 2007): 225–35. http://dx.doi.org/10.1080/10298430701289323.

Full text

APA, Harvard, Vancouver, ISO, and other styles

11

Dinnis, Alan R., and J. Thomas M. Stevenson. "Test specimens for SEM voltage contrast." Microelectronic Engineering 3, no. 1-4 (December 1985): 203–10. http://dx.doi.org/10.1016/0167-9317(85)90029-2.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Doerffel, Christoph, Gábor Jüttner, and Roland Dietze. "Micro Test Specimens for Compound Engineering with Minimum Material Needs." Materials Science Forum 825-826 (July 2015): 928–35. http://dx.doi.org/10.4028/www.scientific.net/msf.825-826.928.

Full text

Abstract:

The use of micro test specimens is a good way to characterize micro injection molding processes and the resulting material properties. The material properties of microparts may differ from standard injection molding parts, due to an overrepresentation of the surface layers with high fiber orientation and divergent morphology. In order to characterize the distribution and agglomeration of fibers and particles for the manufacturing of micro injection molding parts of functionalized polymer compounds, it is essential to manufacture the test specimens and the part using the same process. The distribution and size of these particles e.g. Carbon-Nano-Tubes (CNT) or piezo ceramic particles is dependent on the polymer plastication process during injection molding. Therefore the use of micro test specimens is a requirement for precise material selection and engineering.Due to the minimum material needs, micro test specimens are also useful for the comparison of the material properties of new polymers and compounds, which were produced in amounts of 20 g to 100 g. Another application is the testing of highly elastic and ductile materials with strains over 100%. By using micro test specimens it is possible to test high strains with low elongations in a short time.A new innovative micro test specimen has been developed at the Technische Universität Chemnitz in cooperation with the Kunststoff-Zentrum in Leipzig, that is especially designed for the testing and dimensioning of plastic microparts with weights less than 0.1 g. The main feature of the new specimen and testing process is the combined positive and force-fitted locking, which enables a precise positioning of the micro specimen and an even application of the clamping force. In order to achieve reproducible clamping, testing and handling of the sample, the clamping and testing process are spatially separated. The shape of the test specimen enables a parameter optimization for the micro injection molding process.

APA, Harvard, Vancouver, ISO, and other styles

13

Stanley, P., and C. Karroum. "An evaluation of mechanical strength test specimens for brittle materials." Journal of Strain Analysis for Engineering Design 27, no. 2 (April 1, 1992): 101–11. http://dx.doi.org/10.1243/03093247v272101.

Full text

Abstract:

Several alternative test specimens for the determination of the fracture strength of a brittle material have been studied. These include a ring-supported ball-loaded thin circular disc, a disc symmetrically supported on three equispaced balls and loaded at the centre through a fourth ball, a cylinder under axial compressive point-loading, and a ‘pure shear’ beam specimen. The stress distributions in these specimens have been determined photoelastically and the stress data used to interpret fracture test data for batches of each specimen made from reactor-grade graphite. The stochastic nature of the fracture data has also been considered.

APA, Harvard, Vancouver, ISO, and other styles

14

Meneghetti, Giovanni, Carlo Dengo, and Fulvio Lo Conte. "Bending fatigue design of case-hardened gears based on test specimens." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 11 (May 30, 2017): 1953–69. http://dx.doi.org/10.1177/0954406217712278.

Full text

Abstract:

Different design methods against bending fatigue are reported in ISO 6336 standard. The standard suggests primarily the method based on reference test gears and provides the relevant fatigue curves. Additionally, the standard suggests the use of specimens (instead of gears) to generate the reference fatigue curves, but it also advices that specimen-based methods can be used when gears are not available and that specimens are particularly useful for comparing fatigue performances of gear materials relative to one another. The purpose of the present paper is to evaluate the accuracy of the specimen-based methods mentioned in the ISO standard when applied to design gears against bending fatigue. Experimental data were generated by means of pulsator fatigue tests on case-hardened gears used in off-highway vehicles. Afterwards, experimental results were compared with theoretical estimations according to the approaches based on reference test gears (as suggested by the ISO standard) and test specimens. Concerning the latter approach, the relevant fatigue design curves were generated by testing smooth as well as notched specimens made of the same case-hardened gear steel. It was found that the specimens-based methods are as accurate as the reference gears-based method, provided that the material notch sensitivity factor is properly calibrated on the experimental results obtained from specimens.

APA, Harvard, Vancouver, ISO, and other styles

15

Menu, Bruce, Marc Jolin, and Benoit Bissonnette. "Studies on the Influence of Drying Shrinkage Test Procedure, Specimen Geometry, and Boundary Conditions on Free Shrinkage." Advances in Materials Science and Engineering 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/9834159.

Full text

Abstract:

Although considerable progress has been made in enhancing the use and interpretation of free ring shrinkage test, little is known about the impact of the test procedure, the specimen geometry, the surface area-to-volume (S/V) ratio exposed to drying, and the boundary conditions (sealing configuration) on the measured shrinkage. This paper highlights recent findings illustrating the influence of the test procedure, the S/V ratio exposed to drying, the geometry of specimen, and the boundary conditions. A series of experimental results are presented from free shrinkage on ring test specimens to illustrate that the test procedure can significantly influence the measured free shrinkage. A second series of experimental results are presented from specimens with different geometries and S/V ratio exposed to drying to illustrate that drying shrinkage is dependent on both the specimen geometry and the surface exposed to drying. Test results further show that, even for the same S/V ratio exposed to drying, shrinkage is strongly dependent on the specimen’s geometry and boundary conditions.

APA, Harvard, Vancouver, ISO, and other styles

16

Tayebali, Akhtarhusein A., John A. Deacon, and Carl L. Monismith. "Development and Evaluation of Dynamic Flexural Beam Fatigue Test System." Transportation Research Record: Journal of the Transportation Research Board 1545, no. 1 (January 1996): 89–97. http://dx.doi.org/10.1177/0361198196154500112.

Full text

Abstract:

Although both mix variables and environmental variables are known to affect the fatigue response of asphalt-aggregate mixes, other factors—including specimen fabrication procedure and test equipment and procedures—are equally important. The development of a dynamic flexural beam fatigue test system is described, and the effects of specimen compaction method and equipment type on the precision of in situ fatigue lives of asphalt-aggregate mixes predicted by using laboratory strain-life relationships are discussed. Results indicate a coefficient of variation of 41 percent in fatigue life for the new fatigue equipment compared with one of 93 percent for an earlier electropneumatic version. The specimen compaction method was also found to influence significantly the precision of the predicted fatigue life. A 33 percent difference in coefficients of variation between the fatigue response of rolling wheel–compacted specimens and kneading-compacted specimens was observed. Consequently, twice as many specimens are required to achieve a given level of precision in in situ predicted fatigue life if kneading compaction is used instead of rolling wheel compaction. Similarly, if a pneumatic system and associated test procedure are used, approximately 12 times as many specimens are required to achieve similar precision in predicted fatigue life compared with the new servohydraulic fatigue test system.

APA, Harvard, Vancouver, ISO, and other styles

17

Chaney, RC, KR Demars, TE Cotten, MM Davis, and CD Shackelford. "Effects of Test Duration and Specimen Length on Diffusion Testing of Unconfined Specimens." Geotechnical Testing Journal 21, no. 2 (1998): 79. http://dx.doi.org/10.1520/gtj10746j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

18

Xu, Jia Xiong. "Analysis of Displacement Field of Asphalt Mixture in Uniaxial Compression Test." Applied Mechanics and Materials 423-426 (September 2013): 1055–58. http://dx.doi.org/10.4028/www.scientific.net/amm.423-426.1055.

Full text

Abstract:

In this paper, digital imaging technology is used to research the specimen deformation in asphalt mixture unconfined compressive strength test. We compare of the differences in the average vertical strain with a narrower range of local under three groups different specimens conditions, diameter height ratio of 1:1 specimens which are of specification and end untreateddiameter height ratio of 1:1 specimens which are wax to seal the deal and diameter height ratio of 1:1.5 specimens which are end untreated. We discover that the first two states can be easier to achieve the relatively stable state and better reflect the true stress-strain relationship than the last.

APA, Harvard, Vancouver, ISO, and other styles

19

Liew, Li-Anne, David T. Read, and Nicholas Barbosa. "Bend testing of micro-scale bulk metal specimens using a chip-scale test instrument." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2015, DPC (January 1, 2015): 000827–64. http://dx.doi.org/10.4071/2015dpc-tp36.

Full text

Abstract:

We describe bend testing on micro-scale specimens of 302 stainless steel, using a MEMS test instrument. Bend testing is a common way of measuring the flexural stiffness of structural materials across many size scales, from thin laminate sheets to large weldments. Whereas the stiffness of a material under tensile loading is given by the Young's Modulus, the flexural stiffness, or the stiffness in bending, is much lower. In the past two decades, conventional materials testing machines and the specimens themselves have undergone miniaturization for the purpose of evaluating the mechanical properties of miniaturized mechanical components such as sensors and biomedical implants, for which the smallest specimen dimension is typically around 1 mm [2]. Another driver for miniaturizing the testing apparatuses is to test materials with inherently small form factors such as wires and thin films [3]. Now the emerging 3D printing technology is creating another need for material property measurement at micrometer size scales, to accurately capture the property gradients resulting from the layered manufacturing. However, with ever increasing miniaturization comes increasing difficulty in specimen handling, gripping, and alignment. Concurrently, MEMS technology has been used over the past 2 decades to fabricate small actuators and sensors for mechanical testing of materials of thin films [4] or nanoscale materials such as nanowires. We seek to use the advantages of MEMS to study the mechanical properties of bulk materials rather than thin films, but at the micrometer scale. We believe this will result in greater accuracy and spatial resolution of property measurements of structural materials used in civil infrastructure, aerospace, transportation and energy industries, as well as characterizing manufacturing processes that lead to steep property gradients such as 3D printed components. Our approach is to use MEMS actuators as chip-scale re-useable test instruments into which small specimens sectioned from bulk materials can be inserted and tested [5], to reduce the cost and time to obtain large data sets and to allow the measurements to be done in-situ in harsh environments. We will describe the design of a micro-size 302 stainless steel specimen, and the use of a MEMS test instrument for performing the bend testing on the specimens. The specimen's gage section was 350 um long, 65 um wide and 25 um thick, and was made by lithographic etching of a foil. The MEMS test instrument was fabricated from silicon and glass wafers. The specimens were inserted into the MEMS test chip and the silicon actuator applied static bending loads to the specimen. Displacements were measured from optical microscope images, and the force was calculated from the applied voltage and the known (measured) stiffness of the silicon actuator. The applied force from the MEMS actuator was measured directly, without any specimen, using a custom table-top force probe and load cell apparatus, and was in agreement with the force calculated from the applied voltage. The flexural stiffness of the micro specimens were measured, using the MEMS test device, at 90 – 130 N/m. These values were validated by independently testing the specimens with the much larger table-top force probe. We thus show that our MEMS test chip can be used to perform bending tests on micro scale specimens of bulk materials, but with a 1000-fold reduction in size compared to table-top force-measuring apparatuses.

APA, Harvard, Vancouver, ISO, and other styles

20

Garcia, Victor M., and Alejandro Miramontes. "Understanding Sources of Variability of Overlay Test Procedure." Transportation Research Record: Journal of the Transportation Research Board 2507, no. 1 (January 2015): 10–18. http://dx.doi.org/10.3141/2507-02.

Full text

Abstract:

“Fatigue cracking” is defined as the accumulation of reflective cracking on hot-mix asphalt (HMA) layers under the repeated application of vehicular loads combined with climatic effects. Several highway agencies have either implemented or considered implementing the overlay tester (OT) to evaluate the fatigue cracking resistance of HMA specimens as a function of the number of cycles that the specimen may resist during the test until a reflective crack appears and propagates. The repeatability of the number of cycles to failure measured with the OT is considered as one of the main challenges in reliably evaluating the fatigue cracking resistance of asphalt mixtures. The objective of this paper is to discuss some of the sources and causes of variability of the parameters measured with the OT. Some of the possible causes of inconsistency in the results include the amount of torque applied to attach OT specimens, the amount of glue required for each OT specimen, the curing time of the glue, and the elapsed time between preparation and testing. For a better delineation of the uncertainties associated with the preparation process of HMA specimens and the mechanism of the OT equipment, a thorough study and practical laboratory evaluation of key steps involved in the overlay test protocol were performed on several synthetic and HMA specimens. Through the investigation of the important inconsistencies in the future guidelines, the variability and repeatability of the results from the OT on the number of cycles to failure may be improved.

APA, Harvard, Vancouver, ISO, and other styles

21

Taggart, E. William, Carrie L. Byington, David R. Hillyard, John E. Robison, and Karen C. Carroll. "Enhancement of the AMPLICOR Enterovirus PCR Test with a Coprecipitant." Journal of Clinical Microbiology 36, no. 11 (1998): 3408–9. http://dx.doi.org/10.1128/jcm.36.11.3408-3409.1998.

Full text

Abstract:

The incorporation of a commercially available coprecipitant into the AMPLICOR enterovirus PCR test specimen preparation enhanced the sensitivity and reproducibility of this assay. Fifty-five previously tested archived cerebrospinal fluids (CSF) specimens were tested in a blind study in duplicate with and without Pellet Paint coprecipitant (Novagen, Inc., Madison, Wis.). Of these specimens, 26 had previously been determined to be positive and 29 had previously been determined to be negative. All previously positive CSF specimens were positive when Pellet Paint was used and only 18 were positive without Pellet Paint. No previously negative specimens were positive on repeat testing with or without Pellet Paint. The background signal was not affected by the addition of Pellet Paint. These data support the utility of a coprecipitant in minimizing false-negative results.

APA, Harvard, Vancouver, ISO, and other styles

22

Davidson, B. D., R. Kruger, and M. König. "Three Dimensional Analysis and Resulting Design Recommendations for Unidirectional and Multidirectional End-Notched Flexure Tests." Journal of Composite Materials 29, no. 16 (November 1995): 2108–33. http://dx.doi.org/10.1177/002199839502901602.

Full text

Abstract:

Results are presented from a theoretical investigation of the effects of stacking sequence on the energy release rate in laminated composite end-notched flexure test specimens. Deflections and energy release rates of unidirectional and multidirectional ENF specimens are obtained by classical laminated plate theory, shear deformable plate theory, and three dimensional finite element analyses. It is shown that the distribution of energy release rate varies across the front of an initially straight delamination. The percentage of mode II and mode III energy release rates for the specimen, as well as the local peak values of the mode II, mode III and total energy release rates that occur at the specimen's free edges are shown to correlate with a nondimensional ratio comprised of the specimen's flexural rigidities. The results of the study are used as a basis for a proposed “ENF test design procedure” that may be used for the determination of appropriate specimen stacking sequences and test geometries for studying delamination growth at interfaces between plies at various orientations. The test design procedure minimizes the contributions to the energy release rate from residual thermal stresses, geometric nonlinearities, local mode II concentrations at the specimen's free edges and local mode III effects.

APA, Harvard, Vancouver, ISO, and other styles

23

Martínez-Pañeda, E., I. I. Cuesta, I. Peñuelas, A. Díaz, and J. M. Alegre. "Damage modeling in Small Punch Test specimens." Theoretical and Applied Fracture Mechanics 86 (December 2016): 51–60. http://dx.doi.org/10.1016/j.tafmec.2016.09.002.

Full text

APA, Harvard, Vancouver, ISO, and other styles

24

Chvostová, E., and J. Džugan. "Creep test with use of miniaturized specimens." IOP Conference Series: Materials Science and Engineering 179 (February 2017): 012032. http://dx.doi.org/10.1088/1757-899x/179/1/012032.

Full text

APA, Harvard, Vancouver, ISO, and other styles

25

Brosey, W. D. "Ultrasonic analysis of spherical composite test specimens." Composites Science and Technology 24, no. 3 (January 1985): 161–78. http://dx.doi.org/10.1016/0266-3538(85)90071-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

26

Barr, B. "Compact shear test specimens for FRC materials." Composites 18, no. 1 (January 1987): 54–60. http://dx.doi.org/10.1016/0010-4361(87)90008-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Martín, Vicente, Jesús Vázquez, Carlos Navarro, and Jaime Domínguez. "Fretting-Fatigue Analysis of Shot-Peened Al 7075-T651 Test Specimens." Metals 9, no. 5 (May 21, 2019): 586. http://dx.doi.org/10.3390/met9050586.

Full text

Abstract:

Shot peening is a mechanical treatment that induces several changes in the material: surface roughness, increased hardness close to the surface, and, the most important, compressive residual stresses. This paper analyzes the effect of this treatment on alloy Al 7075-T651 in the case of fretting fatigue with cylindrical contact through the results of 114 fretting fatigue tests. There are three independent loads applied in this type of test: a constant normal load N, pressing the contact pad against the specimen; a cyclic bulk stress σ in the specimen; and a cyclic tangential load Q through the contact. Four specimens at each of 23 different combinations of these three parameters were tested—two specimens without any treatment and two treated with shot peening. The fatigue lives, contact surface, fracture surface, and residual stresses and hardness were studied. Improvement in fatigue life ranged from 3 to 22, depending on fatigue life. The relaxation of residual-stress distribution related to the number of applied cycles was also measured. Finally, another group of specimens treated with shot peening was polished and tested, obtaining similar lives as in the tests with specimens that were shot-peened but not polished.

APA, Harvard, Vancouver, ISO, and other styles

28

Watanabe, Satoru, Yoshiki Ishida, Daisuke Miura, Taira Miyasaka, and Akikazu Shinya. "Development of a Weight-Drop Impact Testing Method for Dental Applications." Polymers 12, no. 12 (November 26, 2020): 2803. http://dx.doi.org/10.3390/polym12122803.

Full text

Abstract:

For evaluating the impact strength of dental materials, the Izod test or Charpy test has been used, but specimen preparation for these tests is difficult due to the adjustment of a notch on them. By contrast, a weight-drop impact test does not require notched specimens. Therefore, it might be possible to measure the impact strength more accurately than conventional methods. This study aimed to establish appropriate conditions for applying the weight-drop impact test on small specimens of acrylic resin. To determine the most reliable impact fracture energy of acrylic resins, different diameters and thicknesses of PMMA resin specimens, diameters and weights of the striker, and diameters of the supporting jig were compared. For all specimen thicknesses, when the striker diameter was 6–10 mm, the impact fracture energy was constant when the inner diameter of the specimen-supporting jig was 8–10 mm. In addition, the measured E50% value was mostly equal to the median value of the impact fracture energy. Thus, for the weight-drop impact test, this method was effective for material testing of small specimens, by clearly specifying the test conditions, such as the thickness of disc-shaped specimens, the diameter of the striker, and the inner diameter of the specimen-supporting jig.

APA, Harvard, Vancouver, ISO, and other styles

29

Chen, Jian, Yong Hao Fang, and Cheng Hui Zhu. "Effect of Shape and Size of Concrete Specimens on Test Result of Chloride Migration Coefficient." Applied Mechanics and Materials 395-396 (September 2013): 520–23. http://dx.doi.org/10.4028/www.scientific.net/amm.395-396.520.

Full text

Abstract:

The chloride migration coefficients of concrete specimens with different shapes and different sizes were tested with modified rapid chloride migration test. The results indicate that the shape and thickness of concrete specimens slightly affect the test results of chloride migration coefficient of concrete specimens; When the size of the diffusion face of the specimen is larger than the electrode plates of the cell, the measured chloride migration coefficient will be a little smaller. The thickness, thus the electrode space also has effect on the test results, the thicker the specimen, the smaller the chloride migration coefficient measured. The effect is larger for that the specimen with the migration face larger than the electrode plates of the cell than those about the same size with the electrode plates

APA, Harvard, Vancouver, ISO, and other styles

30

Lee, Kangjin, Sonja Pape, Cassie Castorena, and Y. Richard Kim. "Evaluation of Small Specimen Geometries for Asphalt Mixture Performance Testing and Pavement Performance Prediction." Transportation Research Record: Journal of the Transportation Research Board 2631, no. 1 (January 2017): 74–82. http://dx.doi.org/10.3141/2631-09.

Full text

Abstract:

The use of small specimen geometries in asphalt mixture performance testing to enable the testing of as-built pavement layers has been gaining attention in recent years. Small specimens could also improve the testing efficiency of laboratory-fabricated specimens by allowing the extraction of multiple test specimens per gyratory-compacted sample. Rigorous assessment of the small specimen geometries is required before the use of such geometries is standardized. In this study, small specimens were evaluated for dynamic modulus and simplified viscoelastic continuum damage fatigue. Three specimen geometries (100-mm- and 38-mm-diameter cylindrical specimens and 25- × 50-mm prismatic specimens) were compared by using five mixtures with a nominal maximum aggregate size (NMAS) ranging from 9.5 to 25.0 mm. The results show that the dynamic modulus and phase angle master curves agreed at low and intermediate temperatures, regardless of the NMAS values of the mixture. At the high temperature, the small specimen dynamic modulus values were slightly higher and the phase angle values were slightly lower than those of the large specimens. The specimen-to-specimen variability for the large and small specimens was comparable. The fatigue test results for the mixtures evaluated were comparable, except for the 25-mm mixture, which proved problematic in the testing of both small and large specimens. Pavement performance was predicted by the layered viscoelastic analysis for critical distresses program by using the test results for the small and large specimens. These results suggest that specimen geometry had a minimal effect on pavement fatigue damage predictions, which indicates promise for the use of small specimen geometries in practice.

APA, Harvard, Vancouver, ISO, and other styles

31

Li, Jian, T. Kevin O'Brien, and Carl Q. Rousseau. "Test and Analysis of Composite Hat Stringer Pull-off Test Specimens." Journal of the American Helicopter Society 42, no. 4 (October 1, 1997): 350–57. http://dx.doi.org/10.4050/jahs.42.350.

Full text

APA, Harvard, Vancouver, ISO, and other styles

32

Adebayo, Adeyinka, Joseph Temitope Stephen, and Gbenga Joshua Adeyemi. "Effects of Local Cooling Media on the Mechanical Properties of Heat Treated Mild Steel." European Journal of Engineering Research and Science 3, no. 4 (April 17, 2018): 27. http://dx.doi.org/10.24018/ejers.2018.3.4.655.

Full text

Abstract:

This paper reports the effects of local cooling media (groundnut oil, palm oil, shea butter and air) on the mechanical properties of heat treated mild steel. Tensile test, hardness test and microstructural analysis were carried out on the heat treated and as-purchased specimens. The results show significant differences in the mechanical properties of the heat treated specimens. The hardness profile showed higher values for palm oil-cooled, shea butter-cooled, and the groundnut oil-cooled specimens in an increasing of order respectively when compared with as-purchased specimen with 194.9 VHN, while a decrease in hardness was recorded for the air-cooled specimen. Furthermore, the yield strength and ultimate tensile strength of the heat treated specimens obtained through the tensile test analysis showed an increase in yield strength for the groundnut oil-cooled (464.4 MPa) and the shea butter-cooled (412.9 MPa) specimens, and a decrease in yield strength for the air-cooled (358.3 MPa) and palm oil-cooled (307.7 MPa) specimens when compared with the as-purchased specimens (376.9 MPa). Also, the same trend was observed in the ultimate tensile strength (UTS) of the specimens. In contrast, the ductility improved in air-cooled specimen (40.28) while decreased in the specimen cooled in the media when compared with as-purchased specimens (34.22). Furthermore, microstructural analysis revealed that the groundnut oil-cooled specimens gave a microstructural quality than the other heat treated specimens.

APA, Harvard, Vancouver, ISO, and other styles

33

Coudron, Philip E., Daniel P. Fedorko, Marilyn S. Dawson, Lisa G. Kaplowitz, Richard R. Brookman, Harry P. Dalton, and Bettie A. Davis. "Detection of Chlamydia Trachomatis in Genital Specimens by the Microtrak™ Direct Specimen Test." American Journal of Clinical Pathology 85, no. 1 (January 1, 1986): 89–92. http://dx.doi.org/10.1093/ajcp/85.1.89.

Full text

APA, Harvard, Vancouver, ISO, and other styles

34

Vincelette, Jean, Jurjen Schirm, Marc Bogard, Anne-Marie Bourgault, Dirk S. Luijt, Anne Bianchi, Pieter C. van Voorst Vader, Ann Butcher, and Maurice Rosenstraus. "Multicenter Evaluation of the Fully Automated COBAS AMPLICOR PCR Test for Detection of Chlamydia trachomatis in Urogenital Specimens." Journal of Clinical Microbiology 37, no. 1 (1999): 74–80. http://dx.doi.org/10.1128/jcm.37.1.74-80.1999.

Full text

Abstract:

The fully automated COBAS AMPLICOR CT/NG test for the detection ofChlamydia trachomatis was evaluated in a multicenter trial. Test performance was evaluated for 2,014 endocervical swab and 1,278 urine specimens obtained from women and for 373 urethral swab and 254 urine specimens obtained from men. Culture served as the reference test. Culture-negative, COBAS AMPLICOR-positive specimens that tested positive in a confirmatory PCR test for an alternative target sequence within the C. trachomatis major outer membrane protein gene were resolved as true positives. The overall prevalence of chlamydia was 4.3% in cervical swabs and 11.0% in urethral swabs from men. When the results for each specimen type were considered separately, the resolved sensitivities were 96.5% (83 of 86) for endocervical swab specimens, 95.1% (39 of 41) for urine specimens from women, 100.0% (41 of 41) for urethral swab specimens from men, and 94.4% (17 of 18) for urine specimens from men; the resolved specificities were 99.4% (1,912 of 1,924) for endocervical swab specimens, 99.8% (1,204 of 1,207) for urine specimens from women, 98.5% (325 of 330) for urethral swab specimens from men, and 100.0% (236 of 236) for urine specimens from men. For the subset of patients from whom both swab and urine specimens were collected, the combined results for both specimen types were used to identify all infected patients. Using these combined reslts as criteria, the resolved sensitivities for the COBAS AMPLICOR test were 82.6% (38 of 46) for endocervical swab specimens, 84.4% (38 of 45) for urine specimens from women, 84.2% (16 of 19) for urethral swab specimens from men, and 89.5% (17 of 19) for urine specimens from men. In comparison, the sensitivity of culture was only 56.5% (26 of 46) for endocervical specimens and 63.2% (12 of 19) for urethral specimens from men. The internal control provided in the COBAS AMPLICOR test revealed that 2.9% of specimens were inhibitory when they were initially tested. Nevertheless, valid results were obtained for 99.1% of specimens because 68.7% of the inhibitory specimens were not inhibitory when a second aliquot of the original sample was tested. Two additional COBAS AMPLICOR-positive specimens were detected by retesting inhibitory specimens. The COBAS AMPLICOR CT/NG test for the detection of C. trachomatis exhibited equally high sensitivities and specificities with both urogenital swab and urine specimens and, thus, is well-suited for use in screening.

APA, Harvard, Vancouver, ISO, and other styles

35

RYCHLIK, Arkadiusz, Krzysztof LIGIER, and Władysław KOZUBEL. "EFFECT OF HOLE-FORMING TECHNOLOGY ON THE DESTRUCTION OF MATERIAL DD11 USED TO MANUFACTURE WHEEL DISCS." Tribologia 279, no. 3 (July 1, 2018): 113–21. http://dx.doi.org/10.5604/01.3001.0012.7019.

Full text

Abstract:

This study presents the results of comparative tests concerning the destruction process of specimens made of material DD11, for which different hole-forming technologies (i.e. drilling and piercing) were applied. For the analysis of cross-sectional properties of a specimen in the process of destruction, relative vibrations of the specimen’s free end as a function of vibrations of a forcing mechanism (vibration inductor) were selected as the diagnostic signal. The tests were carried out on a test stand on which the destruction process of the material’s cross-section was induced by the specimen’s inertial force. Based on the conducted testing, it was found that the average value of cycles to damage a specimen with holes made using the drilling technique were more durable than the specimens with holes made using the piercing method.

APA, Harvard, Vancouver, ISO, and other styles

36

Huang, Tuo, Guo Ping Qian, and Jian Long Zheng. "Investigation into Shear Coefficient for Circle Shear Test Method of Asphalt Mixture." Advanced Materials Research 446-449 (January 2012): 2590–94. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.2590.

Full text

Abstract:

In order to efficiently evaluate the shear properties of asphalt mixture, the circle shear test method is proposed. However, the thickness of upper layer surface and the middle-surface of the asphalt pavement in China are usually less than the height of standard specimen in circle shear test, as well as some laboratory specimens. In order to determine the shear strength for samples at different height, the circle shear test is conducted to the specimens at different height, and the height calibration coefficient for non-standard specimens are proposed. With which the shear strength for samples at different height can be unified and easily determined.

APA, Harvard, Vancouver, ISO, and other styles

37

Gui, Le Le, Tong Xu, Bin An Shou, Han Kui Wang, and Jing Xiang. "Estimation of Fracture Toughness J_IC by Miniature Specimen Hydraulic Bulge Test." Materials Science Forum 898 (June 2017): 753–57. http://dx.doi.org/10.4028/www.scientific.net/msf.898.753.

Full text

Abstract:

The fracture toughness tests and a new miniature specimen technology named hydraulic bulge test (HBT) of 3Cr1Mo1/4V at four service time were carried out. Four J-R resistance curves by single-specimen method with one inch CT specimens were obtained to compute the JIC. Different definitions of equivalent fracture strain according to the section morphologies of HBT testing specimens were compared, and fracture energy of miniature specimens with three different thicknesses (0.4mm, 0.5mm and 0.6mm) were also calculated. Results showed that the typical HBT load-deflection curve can be divided into four sections like SPT curve. Equivalent fracture strain and fracture energy EHB can be chosen as two fracture parameters for the HBT specimen. Ductile fracture toughness JIC can be related approximately linearly to both the equivalent fracture strain and fracture energy EHB.

APA, Harvard, Vancouver, ISO, and other styles

38

Seok, Chang Sung, Jae Sil Park, Hyung Ick Kim, Young Min Lee, Won Hak Cho, and Weon Keun Song. "Evaluation of Fatigue Characteristic of a Real Waterworks Pipe." Key Engineering Materials 297-300 (November 2005): 2471–76. http://dx.doi.org/10.4028/www.scientific.net/kem.297-300.2471.

Full text

Abstract:

The fatigue characteristic of a material or a structure is derived from fatigue tests of standard specimens. However, many researches have reported that test results of standard specimens are very different from those of real structures or components. One reason for this difference is the constraint effects according to the geometrical difference. Therefore, to calculate more accurate fatigue life, the constraint effect must be considered by comparing test results of standard specimens with those of real structures or components. Another reason for this difference is the surface condition. All surfaces of a standard specimen are polished to obtain similar conditions in a fatigue test. However, in a piping system, surface conditions of components are different from each other and very different from that of a standard specimen. Because fatigue life is effected by a surface condition, to evaluate the fatigue life of a piping system, fatigue tests must be conducted with a specimen extracted from a pipe with the same surface condition. The objective of this paper is to evaluate the fatigue characteristic of a real waterworks pipe by conducting fatigue tests with standard specimens and non-standard specimens of base metal and weld metal. Standard fatigue specimens and non-standard specimens were extracted from a steel pipe used in waterworks. Also, fatigue tests of pipes used in water service were carried out and then compared with those of standard specimens and non-standard specimens. From these results the relation between the S-N diagram of a specimen and that of a pipe specimen was evaluated.

APA, Harvard, Vancouver, ISO, and other styles

39

Yang, Shan, Zhiyong Zhou, Yifei Zhao, and Wei Yang. "Study on Dynamic Mechanical Properties of Full Tailings Cemented Backfilling Impacted by Cement-Sand Ratio." Advances in Civil Engineering 2018 (September 23, 2018): 1–8. http://dx.doi.org/10.1155/2018/7184720.

Full text

Abstract:

In order to study the effect of cement-sand ratio on the dynamic mechanical properties of the full tailings cemented backfilling, three sets of full tailings cemented backfilling specimens with different cement-sand ratios were prefabricated. The uniaxial impact of the prefabricated specimens was performed by the Ф50 mm SHPB test system. Test results showed that full tailings cemented backfilling had strong reflection and damping effects on elastic wave propagation. At lower strain rates, specimens presented strength hardening, and at higher strain rates, the test specimens presented rapid-softening strength; the strength-hardened specimen reached the peak stress at 40 μs, and the softening specimen reached the peak stress at about 18 μs; with the increase of strain rate, dynamic compressive strength, growth factor of dynamic strength, peak strain, and dynamic-static strain ratio of specimens increased totally. When the cement-sand ratio increased, ultimate dynamic compressive strength, limit dynamic strength growth factor, and ultimate peak strain of the specimen were higher; at the same strain rate, with the increase of cement content, the dynamic compressive strength, dynamic strength growth factor, and dynamic-static strain ratio of the test piece all decreased. The failure mode of the specimen was crushing failure. Under the same strain rate, when the cement content decreased, there was a higher damage degree of specimens.

APA, Harvard, Vancouver, ISO, and other styles

40

Linh, Nguyen Ngoc, Nguyen Van Hung, Nguyen Xuan Huy, Le Minh Cuong, and Pham Xuan Dat. "Double-Curvature Test of Reinforced Concrete Columns Using Shaking Table: A New Test Setup." Civil Engineering Journal 5, no. 9 (September 1, 2019): 1863–76. http://dx.doi.org/10.28991/cej-2019-03091378.

Full text

Abstract:

This paper proposes a new test setup to study the double-curvature behavior of reinforced concrete (RC) columns using shaking table. In this setup, the seismic action is simulated by the horizontal movement of a long-heavy rigid mass sitting on the top of only one test specimen. The double-curvature mechanism of specimen is affected by the movement of the concrete mass on a test rig consisting four steel hollow-section columns fully anchored to the shaking table. Application of axial load on the specimen is made possible through a pre-stressing equipment connecting to its top and bottom bases. The current setup offers two improvements over the previous ones. First, it makes available greater ranges of test data for conducting bigger sizes of the specimens. Second, it allows to directly measure the variation of axial force in the test specimens while the test implementation can be fast and easy with a high safety margin even until the complete collapse of the test units. The current test setup has been successfully applied on two ½ scaled V-shaped columns. It has been shown that the column specimen with a low axial load level of 0.05f’cAg, where f’c is the concrete strength and Ag is the cross-sectional area of the specimen, can well survive at a ground peak acceleration up to 5.5 (m/s2) with a drift ratio of approximately 2.91%. Meanwhile, the column subjected to moderate axial load level of 0.15f’cAg can survive at a higher ground peak acceleration of 8.0 (m/s2) with a drift ratio of 3.75%. Furthermore, it is experimentally evidenced that the V-shaped cross-section does not deform in-plane under seismic action. The angle between two planes corresponding to the column web and flange are up to 0.03 (rad). This finding is significant since it contradicts the plane strain assumption available in the current design practice.

APA, Harvard, Vancouver, ISO, and other styles

41

Rao, Qiuhua, Zelin Liu, Chunde Ma, Wei Yi, and Weibin Xie. "A New Flattened Cylinder Specimen for Direct Tensile Test of Rock." Sensors 21, no. 12 (June 17, 2021): 4157. http://dx.doi.org/10.3390/s21124157.

Full text

Abstract:

In recent decades, researchers have paid more attention to the indirect tensile test than to the direct tensile test (DTT) of rocks, mainly due to difficulties in the alignment and the stress concentration at the end of an intact cylindrical specimen. In this paper, a new flattened cylinder specimen and a clamp device were designed to obtain the true tensile strength of the rock in DTT. Stress distributions of the specimen with different lengths (l) and cutting thicknesses (t) were analyzed, and damage processes of the specimen were monitored by the Digital Image Correlation (DIC), the fractured sections were also scanned. Different mechanical parameters were also obtained by the DTT of the flattened cylinder specimens and the intact cylinder specimens, as well as the Brazilian disc. Research results show that the tensile strength obtained by DTT is smaller than the Brazilian disc and is slightly greater than the intact cylindrical specimen. The flattened cylinder specimen with 0.20 ≤ 2t/D < 0.68 and 0.10 ≤ l/D ≤ 0.20 is recommended to measure the true tensile strength of rock material in DTT. This new shape of the specimen is promising to be extended in the uniaxial or triaxial direct tension test.

APA, Harvard, Vancouver, ISO, and other styles

42

Li, Peng Fei, and Jing Hui Liu. "Study on Semi-Circular Bending Test Using Digital Image Correlation Method." Applied Mechanics and Materials 438-439 (October 2013): 421–29. http://dx.doi.org/10.4028/www.scientific.net/amm.438-439.421.

Full text

Abstract:

Fracture toughnessJCis sensitive to the characteristic of the material itself, as an effective indicator to appreciate the fracture resistance of the asphalt mixtures, is adopted by more and more researchers. The Semi-Circular Bending Test (SCB) can evaluate the fracture resistance of asphalt mixtures with different kinds of molding means. But currently, the fracture toughnessJCis measured by multi specimens (at least two), the experimental consumption is high, the single specimen calculation formula didnt appear. Using Digital Image Correlation Method (DICM) can compute theJ-contour integral of a single specimen, compared with the results obtained from multi specimens, the repeatability is better, the accuracy is higher. Test and analytic results show that the DICM provide a new approach to study and investigate the fracture toughnessJC.

APA, Harvard, Vancouver, ISO, and other styles

43

Xiao, Quan Dong, Zheng Xing Guo, and Zhong Yuan Zhang. "Behavior of Double-Wall Precast Concrete Shear Wall under Low-Cyclic Reversed Loading Test." Advanced Materials Research 1079-1080 (December 2014): 354–58. http://dx.doi.org/10.4028/www.scientific.net/amr.1079-1080.354.

Full text

Abstract:

This paper describes an ongoing research program on the seismic resistance performance of the double-wall precast concrete (DWPC) shear wall. Low-cyclic reversed loading test of three new full scale specimens are carried out based on the previous studies. The test results indicate that DWPC shear walls have higher initial stiffness, cracking load, yielding load and ultimate load. The displacement ductility ratios of DWPC shear walls are no less than that of cast-in-situ shear wall. The hysteretic curves of all specimens are plump, and the trend of skeleton curves is basically the same. The seismic energy dissipation capacities of DWPC specimens are close to those of cast-in-situ specimen. All the specimens have shown favorable seismic resistance performance.

APA, Harvard, Vancouver, ISO, and other styles

44

Moon, Kyung Man, Sung Yul Lee, Jae Hyun Jeong, and Myeong Hoon Lee. "Evaluation on the Addition of Inhibitor and Surface Treatment to Corrosion Behavior of the Reinforced Steel Bar Embedded in Mortar Specimen." Key Engineering Materials 744 (July 2017): 114–20. http://dx.doi.org/10.4028/www.scientific.net/kem.744.114.

Full text

Abstract:

In this study, seven types of mortar test specimens were manufactured with parameters, that is, the surface of the reinforced steel bar was treated with hot dip galvanizing (Zn) and the surface of the test specimen was coated with underwater paint, and four types of inhibitors (DAW, MCI, DCI, and Silcon) were added in mortars respectively. And, the seven types of mortar test specimens were immersed in seawater for 4 years. The corrosion properties of the reinforced steel bars embedded in mortar test specimens were investigated using electrochemical methods. The corrosion potentials of the test specimens with painting on the surface of the specimen and Zn coating on the surface of the steel bar exhibited the noblest and lowest values respectively after one year, however, after 4 years, the specimens of underwater painting and of addition of Silcon inhibitor indicated the noblest and lowest values of corrosion potentials respectively. Furthermore, the painting specimen exhibited the smallest values of corrosion probability as welll as of the corrosion current density, while, addition of MCI inhibitor showed the highest values of both corrosion probability and corrosion current density. Moreover, the painting specimen showed the smallest value of neutralization degree among all the specimens, and the largest value of neutralization degree was observed at the specimen of natural condition (no adding of inhibitor, no painting and no Zn coating). As a result, it is considered that the addition of inhibitors, coating with hot dip galvanizing (Zn), and painting on the surface have the effects not only to inhibit the neutralization degree but also to increase the corrosion resistance of the embedded steel bar.

APA, Harvard, Vancouver, ISO, and other styles

45

Darcy, Teresa P., Samuel P. Barasch, Rhona J. Souers, and Peter L. Perrotta. "Test Cancellation: A College of American Pathologists Q-Probes Study." Archives of Pathology & Laboratory Medicine 140, no. 2 (February 1, 2016): 125–29. http://dx.doi.org/10.5858/arpa.2015-0022-cp.

Full text

Abstract:

Context Requests for laboratory testing are canceled after a specimen has already been collected from the patient for many reasons. Regardless of the cause, test cancellation represents a significant resource expenditure for laboratories, and many cancellation events impact patient care by delaying the reporting of test results. Objective To survey a wide variety of hospitals to determine the rate, causes, and circumstances surrounding laboratory test cancellation events. Design Institutions (N = 52) prospectively monitored their test cancellation events during a 6-week period or until 75 cancellation events occurred. Information regarding the test cancellation was recorded, including the primary reason for canceling the test. The rate of test cancellation was calculated based on laboratory specimen volume. Laboratory policies relevant to test cancellation were also surveyed. Results A total of 3471 canceled tests were recorded by participating laboratories of 1 118 845 specimens they accessioned, resulting in an aggregate test cancellation rate of 3.1 per 1000 accessions. The most frequently reported reason for test cancellation occurred in the preanalytical phase, and was a duplicate test request, followed by specimen quality reasons including hemolyzed/clotted specimens and insufficient sample quantity for testing. Very few cancellations occurred during the analytical phase of testing. Lower test cancellation rates were reported by larger institutions and by laboratories that received fewer specimens from inpatients. Conclusions Cancellation of patient tests after a specimen had been collected and received remains a significant issue for clinical laboratories. Laboratories should monitor causes of test cancellation to identify targets for process improvement efforts and to improve laboratory utilization. Cancellation events due to incomplete identification or poor specimen quality potentially delay patient care. Cancellations due to duplicate orders or excessive frequency of testing represent operational challenges for the laboratory and inefficiency in the health care system. Policies related to test cancellation should be clearly specified and communicated to users of laboratory services.

APA, Harvard, Vancouver, ISO, and other styles

46

Yang, Zheng, Chang Boo Kim, Chong Du Cho, Hyeon Gyu Beom, and Bin Ren. "The Static and Dynamic Fracture Test of X70 Pipeline Steel." Key Engineering Materials 340-341 (June 2007): 441–46. http://dx.doi.org/10.4028/www.scientific.net/kem.340-341.441.

Full text

Abstract:

The Charpy V notch specimens of X70 pipeline steel with different notch orientation are tested under the static and dynamic conditions at different temperatures. By analyzing the load versus displacement curves and fracture appearances of specimens the relation of fracture behavior and loading rate is investigated. The maximum load increases and the displacement corresponding to maximum load reduces with test temperature decreasing. Both under the static conditions are larger than that under the dynamic conditions. The fracture sections of all test specimens are reduced in the thickness direction and quantity reduced depends on the load rate, notch orientation and test temperature. At the higher temperature, delamination cracks are found on the fracture surface both under the static and dynamic conditions, which are perpendicular to the thickness direction in T-L specimen and perpendicular to the main crack propagation direction in T-S specimen. Influence of loading rate on the delamination crack size and amount is obvious. The fracture initiation energy and total fracture energy increase with test temperature increasing. Influence of loading rate on the total fracture energy is unobvious at the higher temperature, but is obvious at the lower temperature. So the loading rate effects on total fracture energy are relevant to test temperature and notch orientation.

APA, Harvard, Vancouver, ISO, and other styles

47

Myeong, No-Jun, Seung-Wook Han, Jung-Hoon Park, and Nak-Sam Choi. "Technical Review of Specimens under Ultrasonic Fatigue Test." Transactions of the Korean Society of Mechanical Engineers A 37, no. 8 (August 1, 2013): 967–73. http://dx.doi.org/10.3795/ksme-a.2013.37.8.967.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Tan, Seng C. "Analysis of ASTM D 3410 Compression Test Specimens." AIAA Journal 29, no. 8 (August 1991): 1344–46. http://dx.doi.org/10.2514/3.59961.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Kusumawardaningsih, Yuliarti, Ekkehard Fehling, and Mohammed Ismail. "UHPC Compressive Strength Test Specimens: Cylinder or Cube?" Procedia Engineering 125 (2015): 1076–80. http://dx.doi.org/10.1016/j.proeng.2015.11.165.

Full text

APA, Harvard, Vancouver, ISO, and other styles

50

Sumich, M. "MANUFACTURE OF COMPOSITE TEST SPECIMENS FOR DELAMINATION STUDIES." Experimental Techniques 13, no. 10 (October 1989): 20–22. http://dx.doi.org/10.1111/j.1747-1567.1989.tb00952.x.

Full text

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Test specimens'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles