• Computers and Concrete
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• 제15권3호
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• pp.473-484
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• 2015

In this study, the availability of Schmidt hammer has been investigated as a reliable method to determine the quality of concrete in irrigation networks. For this purpose, the 28-day compressive strength of concrete material used in the construction irrigation channel of Bafra lowland, which is one of the most fertile plains in Turkey was examined by means of concrete compression and as well as concrete Schmidt hammer in laboratory conditions. This study was carried out on cylindrical samples to represent the everyday concrete party ($150m^3$) produced by contractor firm as 3 replications. The statistical analysis of experimental data showed that the correlations between the values of 28-day compressive strength of Schmidt hammer and the rebound number was found to be 0.98. Differences of the compressive strength between compression testing and Schmidt hammer were statistically significant at P<0.01. In this context, it was found that the reliability of compressive strength of the concrete compression test are excellent, also the reliability of compressive strength of Schmidt hammer are fair in assessing the quality of concrete irrigation channels.

• Journal of Electrochemical Science and Technology
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• 제15권2호
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• pp.242-252
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• 2024

To date, methods used to assess the interfacial transition zone (ITZ), which represents the boundary between the aggregate and paste inside concretes, have primarily relied on destructive tests, and non-destructive tests has received little attention until recently. This study assessed the interfaces of concretes with lightweight aggregates based on electrochemical impedance spectroscopy (EIS) for high-strength concretes and examined the possibility of estimating the compressive strength of concretes through non-destructive testing using EIS. The experimental results revealed that the impedance of the hardened cement increased with increasing compressive strength and aggregate density. In particular, when the results of impedance measurement were displayed as a Nyquist plot, the intercept of the x-axis depicting the effective conductivity was proportional to the compressive strength. Furthermore, an equivalent circuit was selected to interpret the correlation between cement aggregates and impedance. Consequently, the compressive strength was found to increase with the value of the resistances of the electrolyte filled in continuous pores in the cement aggregate. And, the pores formed in the ITZ affect this value. The resistance at the ITZ for different aggregates was also obtained, and it was found that the resistance was consistent with the results predicted by SEM images of the ITZ and correlated with the strength of the concretes. The proposed method can be used as a way to easily determine the strength of cement according to differences in aggregate.

• 농업과학연구
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• 제39권1호
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• pp.117-123
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• 2012

Pathogenic fungi and bacteria such as Pectobacterium atrosepticum, Clavibacter michiganensis subsp. sepedonicus, Verticillium albo-atrum, and Rhizoctonia solani were the major microorganism which causes diseases in seed potato during postharvest process. Current detection method for disease-infected seed potato relies on human inspection, which is subjective, inaccurate and labor-intensive method. In this study, a reflectance spectroscopy was used to classify sound and disease-infected seed potatoes with the spectral range from 400 to 1100 nm. Partial least square discriminant analysis (PLS-DA) with various preprocessing methods was used to investigate the feasibility of classification between sound and disease-infected seed potatoes. The classification accuracy was above 97 % for discriminating disease seed potatoes from sound ones. The results show that Vis/NIR reflectance method has good potential for non-destructive sorting for disease-infected seed potatoes.

• Journal of the Korean Wood Science and Technology
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• 제33권5호통권133호
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• pp.21-28
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• 2005

For the proper conservation of wooden cultural properties, non-destructive evaluation (NDE) method, which can be used to quantitatively evaluate the internal state of wood members, are needed. In this study, an ultrasonic CT system composed of portable devices was attempted, and the capacity of this system was verified by reconstructing the CT images for two phantoms and two artificially defected specimens. Results from this study showed that the sizes of detected defects were enlarged and the shapes were distorted on the CT images. Also, the positions were shifted somewhat toward the surface of specimen, which is regarded due to the anisotropic property of wood. Compared to the filtered back-projection method, SIRT (simultaneous iterative reconstruction technique) method was determined to be more efficient as the algorithm of image reconstruction for wood. A new ultrasonic CT system is thought to be used as a NDE method for wood. However wood characteristics and wave diffraction within wood made it difficult to accurately evaluate the size, shape and position of defects. To improve the quality of CT image of wood, more research including the relationship between wood and ultrasound is needed, and wood properties should be taken into consideration on the image reconstruction algorithm.

• Computers and Concrete
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• 제20권1호
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• pp.49-56
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• 2017

A clear correlation exists between the compressive strength and elastic modulus of concrete. Unfortunately, determining the static elastic modulus requires destructive methods and determining the dynamic elastic modulus is greatly complicated by the shape and size of the specimens. This paper reports on a novel approach to the prediction of compressive strength in concrete cylinders using numerical calculations in conjunction with the impact-echo method. This non-destructive technique involves obtaining the speeds of P-waves and S-waves using correction factors through numerical calculation based on frequencies measured using the impact-echo method. This approach makes it possible to calculate the dynamic elastic modulus with relative ease, thereby enabling the prediction of compressive strength. Experiment results demonstrate the speed, convenience, and efficacy of the proposed method.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 춘계 학술발표회 초청강연 및 논문집
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• pp.766-777
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• 2008

Currently in increasing number of urban tunnels with small overburden are excavated according to the principle of the New Austrian Tunneling Method (NATM). Successful design, construction and maintenance of NATM tunnel demands prediction, control and monitoring of ground displacement and support stress high accuracy. A magnetic anisotropy sensor is used for nondestructive measurement of stress on surfaces of a ferromagnetic material, such as steel. The sensor is built on the principle of the magneto-strictive effect in which changes in magnetic permeability due to deformation of a ferromagnetic material is measured in a nondestructive manner, which then can be translated into the absolute values of stresses existing on the surface of the material. This technique was applied to measure stresses of H-beams, used as tunnel support structures, to confirm expected measurement accuracy with reading error of about 10 to 20 MPa, which was confirmed by monitoring strains released during cutting tests The results show that this method could be one of the promising technologies for non-destructive stress measurement for safe construction and maintenance of underground rock structures encountered in civil and mining engineering.

• Fisheries and Aquatic Sciences
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• 제25권5호
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• pp.264-275
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• 2022

A non-destructive environmental DNA protocol for the genetic analysis of sea cucumber (Apostichopus japonicus) resources DNA was established. Among the several commercial DNA extraction kits, the DNeasy^® Plant Mini Kit was selected as the best choice to obtain the high-quality genomic DNAs from the mucous sea cucumber. As the temperature and incubation time increased, the amount of extracted environmental DNA was also large, but it was judged that the increased amount did not affect as much as 2-3 times. Therefore, these conditions were not considered to be the main factors to consider in actual environmental DNA extraction. However, the amount of seawater relative to the size of the sample was judged as a major consideration, and a sufficient amount of environmental DNA for analysis was secured when stored within 1 min while stirring the volume of seawater corresponding to the total sea cucumber weight (g). In securing the environmental DNA of sea cucumbers, the mortality rate of sea cucumbers in all experiments was 0, and it was judged that the effects of sea cucumbers were not significant through this treatment. Through the results of this study, sea cucumber DNA research, which has been conducted in a destructive method, can be conducted non-destructively through environmental DNA analysis. Through this study, we have secured a standard protocol that can successfully extract the sea cucumber DNA through environmental DNA. It is not only excellent in terms of time and cost of traditional DNA analysis method currently used, but it is completely non-destructive in the ecosystem of the survey area. It is believed that the system can be transformed in a way that does not affect it. However, it is thought that various standard protocols should be established considering the characteristics of each type.

• Journal of Mechanical Science and Technology
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• 제18권9호
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• pp.1493-1499
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• 2004

This paper describes the speckle shearing interferometry, a non-destructive optical method, for quantitative estimation of void defect and monitoring separation defect inside of a pneumatic tire. Previous shearing interferometry has not supplied quantitative result of inside defect, due to effective factors. In the study, factors related to the details of an inside defect are classified and optimized with pipeline simulator. The size and the shape of defect can be estimated accurately to find a critical point and also is closely related with shearing direction. The technique is applied for quantitative estimation of defects inside of a pneumatic tire. The actual traveling tire is monitored to reveal the cause of separation and the starting points. And also unknown void defects on tread are inspected and the size and shape of defects are estimated which has good agreement with the result of visual inspection.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 춘계 학술발표회 제16권1호
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• pp.408-411
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• 2004

The presence of voids behind tunnel linings results in their deterioration. One proposed method of effectively detecting such voids by non-destructive means is radar. This research is devoted to quantitatively evaluating the efficiency of such non-destructive tests with radar. As a foundation to this ongoing research, which aims to acquire directional information and estimate the shape of specific voids using radar of three-dipole antenna type, an investigation of microwave polarization methods is carried out with various void orientations and void geometries. As the results, it is clarified that the response of microwave polarization modes depends on void geometry and thus there is a possibility of identifying the geometry and orientation of specific voids using radar of three-dipole antenna type.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.315-318
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• 2007

Non-Destructive Health Monitoring using PZT sensors is a major concern and has great significance for research about NDT (Non-Destructive Test). In this paper, we study about the guided wave measurement method using PZT sensors to find cracks and estimate locations. Two aluminum beams bonded with PZT sensors were tested for estimating about the guided wave propagation characteristics and shape of each beam are decided in terms of analytical purpose. NI Signal Acquisition Device and specially designed LabVIEW VI program were used for data acquisition and analysis. The measured data were progressed by using a high-pass filtering.