Journal articles on the topic 'Paper Deterioration Testing'
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1
Mészáros, István, and János Ginsztler. "Magnetic Testing of Power Plant Steel Deterioration." Materials Science Forum 792 (August 2014): 183–88. http://dx.doi.org/10.4028/www.scientific.net/msf.792.183.
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Nowadays, there is increasing importance of the remaining life time estimation of engineering structures. In this work the thermal shock fatigue process induced deterioration of the three different power plant steels was investigated. The tested steels are widely used as steam pipeline base material of power plants. The applied thermal shock fatigue test can model the material degradation due to long term service in high temperature environment. A special AC magnetometer was designed and used for the magnetic measurements at the Department of Materials Science and Engineering of BUTE. In this paper a new high sensitivity magnetic measurement is presented for controlling the thermal shock fatigue deterioration. This measurement technique was developed for non-destructive testing of pipelines and pressure vessels of steam power plants.
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Woytowich, David L., Martin W. King, Myron G. Britton, and Jan A. Oleszkiewicz. "Accelerated testing of a filled polyester E-glass composite in acidic environments." Canadian Journal of Civil Engineering 18, no. 5 (October 1, 1991): 799–809. http://dx.doi.org/10.1139/l91-097.
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This paper describes the results of an accelerated laboratory investigation to measure the rate of deterioration of a newly developed filled plastic composite exposed to acidic (sewage) environments. The specific objective was to compare the relative rates of deterioration of an experimental filled filament wound (FFW) polyester composite immersed in sulfuric (pH 2.23) and acetic (pH 2.22) acid environments at 45 °C. Deterioration was measured in terms of changes in wet specimen weight, loss in dried (soluble) material weight and mechanical properties, the extent of chemical dissolution, and the depth of penetration. Based on regression analyses of these parameters, it was found that the rate of deterioration was a function of the square root of immersion time. Deterioration of the FFW composite in acetic acid was 1.6–3.9 times greater than in the sulfuric acid environment. The loss in wet flexural properties and the dissolution behavior of aluminum trihydrate were not influenced by the type of acid environment. Based on the findings of this study, sulfuric acid is recommended as a standard laboratory test medium for fiberglass reinforced plastic composites used in construction of sewage facilities and pipelines where deterioration due to sulfur oxidizing bacteria is anticipated. Key words: accelerated, polyester, fillers, filament-wound, environment, acidic, durability, composite, septic tanks.
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Feng, Ju, Tianhua Meng, Yuhe Lu, Jianguang Ren, Guozhong Zhao, Hongmei Liu, Jin Yang, and Rong Huang. "Nondestructive Testing of Hollowing Deterioration of the Yungang Grottoes Based on THz-TDS." Electronics 9, no. 4 (April 9, 2020): 625. http://dx.doi.org/10.3390/electronics9040625.
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Terahertz (THz) spectroscopy is an important method in noninvasive detection and diagnosis for historic relics. A new nondestructive testing (NDT) method based on terahertz time-domain spectroscopy (THz-TDS) technology was developed to measure the hollowing deterioration of the Yungang Grottoes in this paper. Hollowing deterioration samples were strictly prepared, and a series of experiments were conducted to ensure the representativeness of the experimental results. A hollowing thickness model was established by the relationship between the thickness of the hollowing deterioration sample and the time difference of the front flaked stone surface and the stone wall surface of the hollowing deterioration samples. The results show that the R-squared value of the model equation reached 0.99795, which implies that this model is reliable. Therefore, the actual hollowing thickness of the Yungang Grottoes can be obtained by substituting the time difference in the proposed thickness hollowing model, where the time difference is obtained from measured THz spectra. The detection method of stone relic hollowing deterioration is easy to apply, which can not only realize qualitative NDT but also quantitative hollowing deterioration thickness determination. This method has crucial practical significance for the repair and strengthening of stone relics similar to the Yungang Grottoes.
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Zielińska, Monika, and Magdalena Rucka. "Non-destructive Testing of Wooden Elements." IOP Conference Series: Materials Science and Engineering 1203, no. 3 (November 1, 2021): 032058. http://dx.doi.org/10.1088/1757-899x/1203/3/032058.
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Abstract Examining the condition of wooden elements is crucial from the perspective of proper structure performance. If the deterioration in the internal wood condition, which displays no symptoms visible from the outside, is detected, the further spread of the deterioration can be prevented. Test results often point to the necessity of conducting repairs and, renovations, replacing the structure of wooden beams, or even substituting a significant part of the structure. To achieve acceptable results, test methods should take into account the anisotropic nature of wood, which includes the shape of annual rings, as well as the location of the core in crosssection. To adopt methods based on physical effects, profound knowledge of wood physics is needed, particularly of interdependence. Apart from simple tests such as a visual inspection or tapping that are used to determine near-surface defects, non-destructive testing (NDT) plays an important role in the process. This paper presents the methods of non-destructive testing of wooden elements. These methods include tests conducted with ground penetrating radar (GPR), thermal techniques, microwaves, acoustic emission, ultrasonic tomography, and X-ray tomography. The paper summarises the use of non-destructive methods, indicating their advantages, disadvantages as well as some limitations.
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Reiterman, Pavel, and Ondřej Holčapek. "Mechanical and Durability Properties of Selected Types of Sandstones." Applied Mechanics and Materials 827 (February 2016): 324–27. http://dx.doi.org/10.4028/www.scientific.net/amm.827.324.
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Present paper is focused on the experimental assessment of three sandstones from different quarries. Mechanical testing was carried out besides water absorption test and determination of frost resistance what is the crucial material parameter for all types of porous rocks. Gradual deterioration due to action of frost was monitored using non-destructive testing – ultrasonic pulse method. Obtained results well describe failure mechanism of studied sandstones of different basic physical properties. It was conducted that main part of deterioration was performed at the beginning of the freeze-thaw cycling.
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Mészáros, István. "Testing of Power Plant Steel Deterioration by Adaptive Nonlinear Harmonics Method (ANLH)." Materials Science Forum 812 (February 2015): 351–56. http://dx.doi.org/10.4028/www.scientific.net/msf.812.351.
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Nowadays, there is increasing importance of the remaining life time estimation of engineering structures. In this work the thermal fatigue process induced deterioration of the three different power plant steels was investigated. The tested steels are widely used as steam pipeline base material of power plants. The applied thermal fatigue test can model the material degradation due to long term service in high temperature environment. In this paper a new high sensitivity magnetic measuring technique is presented called Adaptive Nonlinear Harmonic (ANLH) method. The sensitivity of this measurement is optimized for controlling the thermal fatigue deterioration. The presented novel measurement was developed for non-destructive testing of pipelines and pressure vessels of power plants.
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Niu, Xiang Jie, and Bin Lan. "The Agricultural Products Deterioration Recognition Based on Computer Vision." Applied Mechanics and Materials 602-605 (August 2014): 2027–30. http://dx.doi.org/10.4028/www.scientific.net/amm.602-605.2027.
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The computer vision technology is an important branch of computer science and artificial intelligence which is regarded as a non-destructive testing technique in the field of agriculture with a broad application prospects. This paper introduces the application of the computer vision technology in the agricultural products deterioration recognition, builds foundations for the accurate measurement of the agricultural products quality with computer visions, and establish the relationship between the feature information and quality of the agricultural products. Meanwhile, this paper combined the computer vision technology with infrared, microwave, NMR techniques to extract and test the visual information of the internal quality of the agricultural products.
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Mechefske, C. K., and Y. Yang. "Failure diagnosis of a type of hydraulic knee joint controller." Prosthetics and Orthotics International 25, no. 2 (August 2001): 148–53. http://dx.doi.org/10.1080/03093640108726589.
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The development of the hydraulic artificial knee joint controller has significantly improved the quality of life for many amputees. Even though the controller unit is very reliable, gradual deterioration inevitably takes place because the unit consists of many moving parts and is subjected to repetitive loads. This paper describes a simple method to test the reliability of hydraulic artificial knee joint controllers. A life cycle testing machine for artificial knee controllers was designed as part of this programme. This study included life cycle testing of 5 knee controllers. Performance measurements representing the different degrees of deterioration were recorded and correlated against the actual deterioration found during refurbishment of the units. The results can be used (with care), together with simple tests, to judge performance of a given unit.
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ABDEL-KAREEM, OMAR. "Evaluating the Combined Efficacy of Polymers with Fungicides for Protection of Museum Textiles against Fungal Deterioration in Egypt." Polish Journal of Microbiology 59, no. 4 (2010): 271–80. http://dx.doi.org/10.33073/pjm-2010-041.
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Fungal deterioration is one of the highest risk factors for damage of historical textile objects in Egypt. This paper represents both a study case about the fungal microflora deteriorating historical textiles in the Egyptian Museum and the Coptic museum in Cairo, and evaluation of the efficacy of several combinations of polymers with fungicides for the reinforcement of textiles and their prevention against fungal deterioration. Both cotton swab technique and biodeteriorated textile part technique were used for isolation of fungi from historical textile objects. The plate method with the manual key was used for identification of fungi. The results show that the most dominant fungi isolated from the tested textile samples belong to Alternaria, Aspergillus, Chaetomium, Penicillium and Trichoderma species. Microbiological testing was used for evaluating the usefulness of the suggested conservation materials (polymers combined with fungicides) in prevention of the fungal deterioration of ancient Egyptian textiles. Textile samples were treated with 4 selected polymers combined with two selected fungicides. Untreated and treated textile samples were deteriorated by 3 selected active fungal strains isolated from ancient Egyptian textiles. This study reports that most of the tested polymers combined with the tested fungicides prevented the fungal deterioration of textiles. Treatment of ancient textiles by suggested polymers combined with the suggested fungicides not only reinforces these textiles, but also prevents fungal deterioration and increases the durability of these textiles. The tested polymers without fungicides reduce the fungal deterioration of textiles but do not prevent it completely.
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He, Ye, Kui Wang, Yuehui Ji, Guoyin Wu, and Mingjie Zhao. "Evaluation of Cumulative Damage of Sandstone under Cyclic Wetting and Drying through Acoustic Wave Parameters and Resistivity Testing." Journal of New Materials for Electrochemical Systems 23, no. 4 (December 31, 2020): 256–61. http://dx.doi.org/10.14447/jnmes.v23i4.a06.
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This paper carries out cyclic wetting and drying experiments on the sandstones from the bank slope of an inland port, and explores the deterioration features and acoustic wave parameters and resistivity (AWPR) of the sandstone. The variations in P-wave velocity, attenuation coefficient, nonlinear coefficient, resistivity, and other indices with the cycle number were discussed in details. Then, the correlations between P-wave velocity, resistivity, and physical-mechanical indices were analyzed based on the experimental results. Through the analysis on instantaneous damage analysis, a cumulative damage model was proposed, in the light of the AWPR. The results show that: the evolution of sandstone resistivity can accurately reflect the deterioration features of the sandstone under cyclic wetting and drying, providing a desirable tool to characterize rock strength deterioration and internal damage changes. Taking cycle number into account, the proposed theoretical model for cumulative damage can derive the damage and deterioration of sandstone excellently. By this model, the AWPR at any moment can be acquired in real time on site, which is convenient for engineering application.
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Dalgliesh, W. Alan, and Donald A. Taylor. "The strength and testing of window glass." Canadian Journal of Civil Engineering 17, no. 5 (October 1, 1990): 752–62. http://dx.doi.org/10.1139/l90-088.
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This paper presents some of the background to the new Canadian General Standards Board (CGSB) standard on the structural design of glass for buildings. It also describes strength testing of window glass at the Institute for Research in Construction of the National Research Council of Canada using three quite different testing machines. (i) A dynamic glass testing rig, with a large 2.35 m diameter piston, applies dynamic air pressures to large panes of glass in the vertical position. Results of 107 tests to failure show the considerable effect of loading rate on strength. (ii) A loading table applies linearly increasing pressures to panes of glass in the horizontal position. Results from 47 fifteen-year-old windows confirm assumptions about the deterioration of strength with in-service use in the new CGSB standard on the structural design of glass for buildings. (iii) A ring-on-ring tester applies linearly increasing loads to small 180 × 180 mm samples; the equivalent of coupon tests for steel or cylinder tests for concrete. The resulting uniform tensile stress fields avoid failures starting at the edges of the samples. Some results are given. Testing provides the basis for the structural design of glass cladding as it does for other structural materials. A great deal more testing of window glass is required. Key words: glass strength, window strength, testing, strength deterioration, rate effect, dynamic loading.
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Li, Wei Hong, Ying Ying Xu, and Yi Han Wang. "Design and Application of a Test Device for Concrete Durability under the Action of Multiple Factor Coupling." Key Engineering Materials 633 (November 2014): 490–93. http://dx.doi.org/10.4028/www.scientific.net/kem.633.490.
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This paper discusses the testing equipment of concrete deterioration under the coupled action of multiple factors. It discusses the classification, advantages and disadvantages which are related to the test system and studies the charge loading device design and the key problems. At last the paper forecasts the prospect of loading device design.
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Topolář, Libor, Peter Rypák, Kristýna Šamárková, and Pavel Rovnaník. "Non-Destructive Testing during the Hardening of Alkali-Activated Slag." Applied Mechanics and Materials 732 (February 2015): 329–32. http://dx.doi.org/10.4028/www.scientific.net/amm.732.329.
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Non-destructive acoustic analysis methods, Impact-echo method as a traditional and the Acoustic Emission method as nontraditional method for civil engineering, were used for experiment. This paper reports the experiment during hardening and drying of specimens of alkali activated slag mortars. Alkali activated slag is a material having a great potential to be used in practice. The main drawback of this material is a high level of autogenous and especially drying shrinkage, which causes a deterioration of the mechanical properties. The aim of this paper is introduce the effect of method used and time curing on the microstructure of alkali activated slag mortars. An understanding of microstructure–performance relationships is the key to true understanding of material behaviours.
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Guo, Jinjun, Wenqi Sun, Yaoqun Xu, Weiqi Lin, and Weidong Jing. "Damage Mechanism and Modeling of Concrete in Freeze–Thaw Cycles: A Review." Buildings 12, no. 9 (August 28, 2022): 1317. http://dx.doi.org/10.3390/buildings12091317.
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The deterioration of concrete microstructures in freeze–thaw (F-T) cycles is the primary reason for the reduction in the service life of concrete. This paper reviews recent progress in the theory of damage mechanisms and damage models of concrete in F-T cycles. It is a detailed review of the salt-freeze coupling condition, microstructure testing, and models for the evolution of concrete properties that are subjected to F-T damage. Summarized in this paper are the deterioration theory of water phase transition; the mechanism of chloride-F-T and sulfate-F-T damage; the microstructure testing of hydration products, pore structure, microcracks, and interfacial transition zones (ITZ). Furthermore, F-T damage models for the macrostructure are presented. Finally, the issues that are existing in the research and outlook of concrete F-T damage are highlighted and discussed. This paper is helpful in understanding the evolution of F-T damage, and also provides a comprehensive insight into possible future challenges for the sustainable design and specifications of concrete in cold environments.
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Mészáros, István, and János Ginsztler. "Magnetic Investigation of Thermal Shock Fatigue Process." Key Engineering Materials 345-346 (August 2007): 1283–86. http://dx.doi.org/10.4028/www.scientific.net/kem.345-346.1283.
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In the present paper we summarize some of our results obtained in the field of magnetic testing of thermal shock fatigue testing of power plant steels. In this work 15Mo3 type ferritic heat resistant steel was investigated. This steel and several similar grades are commonly used in power plants boilers as the material of reheating steam pipelines and pressure vessels. Their typical application temperature is about 500-550 °C. It is commonly accepted that a combined form of mechanical, thermal fatigue and the creep processes causes the long term deterioration of this structural steels. The applied thermal shock fatigue test can model the material degradation due to long term service in high temperature environment. A parallel motion vibrating sample magnetometer, an AC permeameter and a magnetic Barkhausen noise measuring device was used for testing the magnetic properties of the samples and several different magnetic properties were measured to characterize the microstructural processes of the deterioration.
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Ivanič, Andrej, and Samo Lubej. "Durability and Degradation of PVC-P Roofing Membrane—Example of Dynamic Fatigue Testing." Polymers 14, no. 7 (March 24, 2022): 1312. http://dx.doi.org/10.3390/polym14071312.
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This paper presents a study of PVC-P waterproofing membrane Specimens. The Specimens were taken from different segments of a flat roof after a service life of 11 years. The reason for analysing the condition of the Specimens was the apparent degradation of the waterproofing, which no longer guaranteed the watertightness of the roof. The analysis of the performance of the Specimens was based on the control of the mechanical properties, which were compared with the declared values. The mechanical properties of the degraded PVC-P waterproofing membranes with a polyester mesh backing, which are prescribed by the standards, do not usually deviate from the declared properties. This often poses a problem for liability and warranty claims due to the poor quality of the waterproofing membrane. There may be several causes of degradation of PVC-P. For this reason, in this paper, we present the possibility of controlling the properties of PVC-P waterproofing membranes using cyclic dynamic fatigue, microstructure analysis using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the cause of the deterioration of the PVC-P waterproofing membranes is often related to dehydrochlorination of the polymer. However, the deterioration of the mechanical properties of the PVC-P waterproofing membranes can be successfully demonstrated by cyclic dynamic fatigue.
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Nikolov, Nikolay, Yordanka Marcheva, and Veselin Tsonev. "Methods for preparation of corroded steel specimens for mechanical testing." MATEC Web of Conferences 287 (2019): 07004. http://dx.doi.org/10.1051/matecconf/201928707004.
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Steel parts and structures are often used in an aggressive environment, which causes corrosion. Corrosion leads to deterioration of the mechanical properties of steel in two ways. First, it reduces the area of the carrying cross sections. Second, it increases surface defects, which are stress concentrators. Therefore, it is necessary to study the impact of corrosion on the mechanical properties of steel. The paper reviews the methods for causing corrosion of steel specimens for mechanical testing. The impact that the corrosion method and the degree of corrosion have on the mechanical properties of steel is also discussed.
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Verma, Sanjeev Kumar, Sudhir Singh Bhadauria, and Saleem Akhtar. "Review of Nondestructive Testing Methods for Condition Monitoring of Concrete Structures." Journal of Construction Engineering 2013 (April 4, 2013): 1–11. http://dx.doi.org/10.1155/2013/834572.
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The deterioration of concrete structures in the last few decades calls for effective methods for condition evaluation and maintenance. This resulted in development of several nondestructive testing (NDT) techniques for monitoring civil infrastructures. NDT methods have been used for more than three decades for monitoring concrete structures; now it has been recognized that NDT plays an important role in the condition monitoring of existing RC structures. NDT methods are known to be better to assess and evaluate the condition of RC structures practically. This paper reviewed several available NDT methods developed and used in the last few decades.
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Brown, S. F., and C. J. Brown. "Laboratory Facility for Testing Road Iron work Installations." Transportation Research Record: Journal of the Transportation Research Board 1624, no. 1 (January 1998): 237–45. http://dx.doi.org/10.3141/1624-28.
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The term “road ironwork” is used to refer to covers that are placed over manholes, drainage gullies, water valves, and the like. Such ironwork can be found in virtually all highways, especially in urban areas. Highway engineers have to deal with a high incidence of premature failure in these installations, the total costs of which are estimated to be £207 million (U.S. $338 million 1998) per year in the United Kingdom alone. These failures are generally characterized by gradual deterioration of the surrounding asphalt surfacing, associated with failure of the bedding material that supports the ironwork frame. The reasons for this high incidence of failure were investigated in a research project involving the construction of a full-scale laboratory test facility to simulate field conditions. This paper contains a description of the development of this apparatus. The results recorded from the apparatus were later used to identify the failure mechanisms that develop within road ironwork installations.
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Brodņevs, Deniss, and Aleksandrs Kutins. "An Experimental Study of Ground-Based Equipment Real Time Data Transfer Possibility by Using Cellular Networks." Electrical, Control and Communication Engineering 12, no. 1 (July 1, 2017): 11–19. http://dx.doi.org/10.1515/ecce-2017-0002.
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Abstract An expanding mobile cellular network data transfer service offers cheaper wireless solutions for various data transfer needs. This paper presents an experimental testing of data transfer performance in 3G and 4G modes. The purpose of testing was to check the possibility of real-time and critical data transfer over the mobile cellular networks. The testing was performed in Riga in July and August 2016 using the most popular mobile service operators in Latvia: Tele2-LV, BITE-LV and LMT. The testing confirmed that the overload of Riga’s 4G networks causes serious service deterioration or even interruption. Riga’s 3G networks are more stable. However, 3G network service quality depends on a cell load. Lightly loaded 3G network meets real-time data transfer requirements of 100 ms one-way delay of the small packet traffic.
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Mohammad, Maziah, and Ros Asmah Zahari. "Structural Repair to Conserve Langkawi’s Main Tourist Attraction: Practical Approach." MATEC Web of Conferences 199 (2018): 10009. http://dx.doi.org/10.1051/matecconf/201819910009.
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Direct exposure to marine environment causes accelerated corrosion process of all reinforced concrete structures, consequently, causes cracks, deterioration and overall reduction in the sstructural integrity. The aim of this paper is to study the deterioration and technique of repair work at Eagle Square as a landmark of Langkawi Island. Most of the structural problems which occurred at the splash zone were spalling and delamination on beam, slab and pile cap. Material testing was carried out at selected locations to ob tain detailed information relating to the extent and causes of deterioration of the structure. The result showed that the carbonation depth was smaller than concrete cover and the amount of chloride ions was 0.23% by mass of cement and 50% of the splash zone was having 90% probability of corrosion. After obtaining the necessary data, the study directed towards deciding the remedial work. The Eagle Square structure members were successfully repaired in eight (8) months with proper works planning and repair technique appropriate to the damages.
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Mak, Michele Win Tai, Pieter Desnerck, and Janet M. Lees. "Correlation between surface crack width and steel corrosion in reinforced concrete." MATEC Web of Conferences 199 (2018): 04009. http://dx.doi.org/10.1051/matecconf/201819904009.
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Reinforced concrete structures are subjected to weather conditions, chemical attack and other sources of deterioration that can affect their performance. In particular, corrosion of the internal steel reinforcement is considered to be one of the main causes of structural deterioration. A possible consequence of corrosion is cracking of the surrounding concrete. Visual inspections are often used to inform asset management strategies. Finding a relationship between cracks that are visible on the outer surface of a structure and corrosion of the internal reinforcement can be helpful when making assessment decisions. To this end, unconfined cylindrical concrete specimens with an embedded steel bar have been subjected to accelerated corrosion using an impressed current density of 200µA/cm2, leading to steel mass losses between 5-24%. This paper discusses the measured correlation between corrosion-induced surface crack widths and degree of reinforcement corrosion. The tests highlighted some limitations of a set-up that is commonly adopted for accelerated corrosion and concentric pull-out bond testing. The findings of this study represent a first step towards the standardisation of accelerated corrosion testing procedures using an impressed current.
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Teng, Kah, Patryk Kot, Magomed Muradov, Andy Shaw, Khalid Hashim, Michaela Gkantou, and Ahmed Al-Shamma’a. "Embedded Smart Antenna for Non-Destructive Testing and Evaluation (NDT&E) of Moisture Content and Deterioration in Concrete." Sensors 19, no. 3 (January 28, 2019): 547. http://dx.doi.org/10.3390/s19030547.
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Concrete failure will lead to serious safety concerns in the performance of a building structure. It is one of the biggest challenges for engineers to inspect and maintain the quality of concrete throughout the service years in order to prevent structural deterioration. To date, a lot of research is ongoing to develop different instruments to inspect concrete quality. Detection of moisture ingress is important in the structural monitoring of concrete. This paper presents a novel sensing technique using a smart antenna for the non-destructive evaluation of moisture content and deterioration inspection in concrete blocks. Two different standard concrete samples (United Kingdom and Malaysia) were investigated in this research. An electromagnetic (EM) sensor was designed and embedded inside the concrete to detect the moisture content within the structure. In addition, CST microwave studio was used to validate the theoretical model of the EM sensor against the test data. The results demonstrated that the EM sensor at 2.45 GHz is capable of detecting the moisture content in the concrete with linear regression of R2 = 0.9752. Furthermore, identification of different mix ratios of concrete were successfully demonstrated in this paper. In conclusion, the EM sensor is capable of detecting moisture content non-destructively and could be a potential technique for maintenance and quality control of the building performance.
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Magda, Aurelian Vasile, and Cosmin Codrean. "Corrosion Resistance Testing of the Galvanized Sheet Metal Braze Welding Joints." Key Engineering Materials 627 (September 2014): 189–92. http://dx.doi.org/10.4028/www.scientific.net/kem.627.189.
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The joining of the galvanized sheet is normally difficult to be done with classical methods, requiring special attention to the specific problems involved during the welding process. This paper presents the development of the joint technology by Cold Metal Transfer (CMT) of galvanized steel sheet using as filler material a CuSi wire electrode. The salt fog corrosion test was made to certify anticorrosive protection of the galvanized sheet metal joints. This test revealed a minimal deterioration of the galvanized zinc coating during welding and also confirms that using adequate technology galvanized steel can be weld without affected anticorrosive protection of the zinc layer.Experimental researches include optimization of the welding technology using CMT concept; technical skill development solutions of the joints; elaboration and implementation of laboratory advanced technology; experimentation and demonstration of technology functionality by obtaining of braze welded joints corrosion resistant.
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MARZI, HOSEIN. "HIGH-SPEED RT MONITORING SYSTEM USING NEURAL NETWORKS." International Journal of Software Engineering and Knowledge Engineering 15, no. 02 (April 2005): 439–45. http://dx.doi.org/10.1142/s0218194005002312.
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This paper describes a high-speed reconfigurable neural networks for monitoring operational status of automated machinery. Continuous operation of precision machines may change their system performance due to wear, deterioration, or failure. A Learning Vector Quantization (LVQ) based technique is developed that is capable of monitoring system status accurately, and updating its knowledge base with new heuristic data. This method is adapted for practical application to solve problems of condition monitoring and fault diagnosis where a number of fault signatures are initially available. In these situations, the aim is health monitoring, including identification of deterioration of the healthy condition and identification of causes of the failures. A hard real-time system is designed and implemented. An early-warning system monitors sensitive parameters of pressure and current sensors. Their variations beyond a defined healthy threshold trigger a non-destructive testing, which produces transient signals. Correlating the transient pattern of a fault with a database of known failures determines the severity and degree of deterioration of the system. Vigorous tests on real machines indicated an accuracy of 92.3% for the LVQ based monitoring system.
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Gołaszewski, Jacek, Tomasz Ponikiewski, Grzegorz Cygan, and Małgorzata Gołaszewska. "Laser System for Testing Early Shrinkage of Concrete Elements in Conjuction with the Deterioration of the Setting Time." Transactions of the VŠB – Technical University of Ostrava, Civil Engineering Series. 16, no. 2 (December 1, 2016): 25–34. http://dx.doi.org/10.1515/tvsb-2016-0011.
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Abstract The paper presents a method for testing the shrinkage of concrete beams with dimensions of 10x10x50cm. Measurements followed from setting into the form until 24 hours after setting. It was used modified TLS system, which originally was meant for the determination of changes in the length of thin-mortar. Simultanously measured were the changes of speed propagation of sound waves by Vikasonic, what allows to specify the setting time of binders. It could be a base for determining the scratch resistance of the concrete in the first 24 hours after casting.
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Hauer, Ezra. "Statistical Test of Difference between Expected Accident Frequencies." Transportation Research Record: Journal of the Transportation Research Board 1542, no. 1 (January 1996): 24–29. http://dx.doi.org/10.1177/0361198196154200104.
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A primer on the testing of some common statistical hypotheses in road safety is presented. The basic notions of statistical hypothesis testing are reviewed and applied to the specific circumstance when one wishes to test a statistical hypothesis about a change in the expected accident frequency beyond what is the result of a change in traffic and similar influences. The hope is that this exposition will illumine the meaning and intricacy of such tests, inform the decision about when such tests are called for, help users choose the right significance or power, and, because software is now available, improve practice in this matter. A companion paper on the detection of deterioration in safety makes use of the foundation provided.
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Zhu, Fu Min, Quan Gan, and Ya Fei Li. "Weakened Support Detection Based on Road Slab Vibration Response." Applied Mechanics and Materials 319 (May 2013): 528–31. http://dx.doi.org/10.4028/www.scientific.net/amm.319.528.
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This paper presents a vibration testing method to monitor the deterioration and weakened support on slabs of cement concrete pavement. After discussing on methods for void evaluation, a dynamic finite element model of road slab with Winkler foundation assume is established according to the structure of slabs both in good condition and conditions with varying degrees’ defects, and computer simulation to vibration characteristic is conducted and a corresponding measuring system is proposed. Its results can be used to guide actual test.
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Rodrigues, J. Delgado, A. P. Ferreiro Pinto, A. E. Charola, L. Aires-Barros, and F. M. A. Henriques. "Selection of Consolidants for Use on the Tower of Belem / Auswahl eines Steinfestigers für den Turm von Belem." Restoration of Buildings and Monuments 4, no. 6 (December 1, 1998): 653–66. http://dx.doi.org/10.1515/rbm-1998-5323.
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Abstract During the exterior conservation project of the Tower of Belem, Lisbon, it was noticed that although most of the Lioz limestone used in its construction was in good condition, some specific areas presented severe powdering and flaking deterioration patterns. These are mainly due to the effect of natural weathering, including anthropogenic air-pollution, on poorer quality Lioz limestone. Since the deterioration affects mainly the immediate surface and subsurface of the stone blocks, the application of stone consolidants was considered as the most appropriate solution for this problem. This paper describes the difficulties encountered in the evaluation of the tested consolidants-an ethyl silicate ester, an acrylic resin and an epoxy resin-applied in situ. The laboratory and on-site testing used in the final selection are described as well as the actual approach to consolidating the different areas that required this treatment.
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Kailey, Allan, and Gupta Rishi. "Current State of Modern Rammed Construction: A Case Study of First Peoples House after Seven Years Exposure." Key Engineering Materials 666 (October 2015): 63–76. http://dx.doi.org/10.4028/www.scientific.net/kem.666.63.
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This paper presents a study on the current condition of the First Peoples House, located at the University of Victoria in British Columbia. The building houses two rammed earth walls that exemplify the use of stabilized rammed earth as a modern construction material. These rammed earth walls have been exposed to 7 years of natural weathering in a wet climate. A rebound hammer, infrared camera, and a new method developed to quantify surface deterioration were used in Non-Destructive Testing (NDT). The results provided insight into the compressive strength, thermal envelope and surface condition of the walls. Relationships between wind direction and wind speed are presented. It is postulated that the wall that is most exposed to a combination of both effects will exhibit the largest forms of deterioration. This hypothesis was addressed using results from NDT and local wind data.
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Ubanwa, B., A. Burnette, S. Kishan, and S. G. Fritz,. "Exhaust Particulate Matter Emission Factors and Deterioration Rate for In-Use Motor Vehicles." Journal of Engineering for Gas Turbines and Power 125, no. 2 (April 1, 2003): 513–23. http://dx.doi.org/10.1115/1.1559904.
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Recent measurements and modeling of primary exhaust particulate matter (PM) emissions from both gasoline and diesel-powered motor vehicles suggest that many vehicles produce PM at rates substantially higher than assumed in the current EPA PM emission factor model, known as “PART5.” The discrepancy between actual versus modeled PM emissions is generally attributed to inadequate emissions data and outdated assumptions in the PART5 model. This paper presents a study with the objective of developing an in-house tool (a modified PART5 model) for the Texas Natural Resource Conservation Commission (TNRCC) to use for estimating motor vehicle exhaust PM emissions in Texas. The work included chassis dynamometer emissions testing on several heavy-duty diesel vehicles at the Southwest Research Institute (SwRI), analysis of the exhaust PM emissions and other regulated pollutants (i.e., HC,CO,NOx), review of related studies and exhaust PM emission data obtained from literature of similar types of light and heavy-duty vehicle tests, a review of the current PART5 model, and analysis of the associated emission deterioration rates. Exhaust PM emissions data obtained from the vehicle testing at SwRI and other similar studies (covering a relatively large number and wide range of vehicles) were merged, and finally, used to modify the PART5 model. The modified model, which was named PART5-TX1, was then used to estimate new exhaust PM emission factors for in-use motor vehicles. Modifications to the model are briefly described, along with emissions test results from the heavy-duty diesel-powered vehicles tested at SwRI. Readers interested in a detailed understanding of the techniques used to modify the PART5 model are referred to the final project report to TNRCC (Eastern Research Group 2000).
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P N, Ojha, Adarsh Kumar N S, Brijesh Singh, Abhishek Singh, and Vikas Patel. "A case study on deterioration assessment and rehabilitation of fire damaged reinforced concrete structure." Journal of Building Materials and Structures 8, no. 1 (July 1, 2021): 72–81. http://dx.doi.org/10.34118/jbms.v8i1.1158.
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Fire is one of the most severe hazards that building structures may experience during their lifetime. A fire spread to the whole structure can cause unexpected damages to the structural elements. Mainly, the building type is crucially important for the type and the level of damage to the building because of the fire. Post fire investigation of damaged structure is required to determine the extent of damage to concrete elements and to work out system of effective repair/rehabilitation measures to maintain the structural integrity of fire effected structural components. The paper covers in brief the strength and durability study on fire damaged building in Delhi, India. The study reports the extent of fire damage. Optical Microscopy (OM), X-Ray Diffraction (XRD) and Deferential Thermal Analysis (DTA) studies were carried out on the sample concrete cores extracted from different identified portions of the fire exposed concrete are highlighted in this paper. Extent of damage occurred in the Reinforced Cement Concrete (RCC) i.e. RCC columns/beams/slabs are described based on the detailed evaluation by various Non-Destructive Evaluation Techniques covering Cover study & Ultrasonic Pulse Velocity (UPV) testing. Repair and remedial measures required for restoration and strengthening of the fire affected RCC columns/beams/slabs using indigenously available repair materials and techniques are also highlighted in this paper.
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Budziński, Rafał, and Lucjan Ślęczka. "Behaviour of steel sheeting connections with self-drilling screws under variable loading." Open Engineering 10, no. 1 (June 20, 2020): 527–35. http://dx.doi.org/10.1515/eng-2020-0058.
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AbstractConnections made by self-drilling screws are often used in steel cold-formed structures and sheeting. Their structural properties, such as resistance, flexibility and ductility are obtained by testing under monotonically increasing loading and can influence on overall behaviour of structures. This paper presents results of experimental study how variable load deteriorates those structural properties of lap shear connections with self-drilling screws. One monotonic and four variable loading histories were utilized, with displacement and force control. Applied loading histories were aimed to simulate persistent design situation, which referred to the conditions of normal use according to EN 1990. Deterioration of resistance and flexibility have been assessed for each variable loading history. It was observed that resistance deterioration is directly proportional to loading range. In case of flexibility, at small displacement range connectors become stiffer. Degradation of flexibility starts to increase at larger displacement range.
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Livneh, Moshe. "Determination of residual life in flexible pavements." Canadian Journal of Civil Engineering 23, no. 5 (October 1, 1996): 1012–24. http://dx.doi.org/10.1139/l96-908.
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In the field of pavement rehabilitation design, one finds a prominent absence of uniformity in the principles of calculation, a lack of clarity as to the testing methods, and a confusion of basic physical concepts. An example of this situation is the residual life of the pavement structure, which constitutes an important measure in the calculation of pavement bearing capacity. The basic question of how to establish such a parameter in practice is discussed in this paper by examining the relationships between the residual life parameter and the pavement surface state, the pavement structural state, the pavement functional state, and the effects of asphalt fatigue or the total structural deterioration on the residual life-span. Finally, this paper suggests a method for including the residual life parameter within the design process of flexible pavement rehabilitation. Key words: cracking, damages, deflection, permanent deformation, evaluation, fatigue, flexible pavements, overlay, rehabilitation, service level, visual testing.
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Chiang, W. K., and Y. C. Chan. "Reliability of Anisotropic Conductive Film Joints Using Bumpless Chip—Influence of Reflow Soldering and Environmental Testing." Journal of Electronic Packaging 127, no. 2 (June 1, 2005): 113–19. http://dx.doi.org/10.1115/1.1849236.
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This paper presents the reliability of anisotropic conductive film (ACF) joint tested under reflow soldering and environmental test effect. The ACF joint behaved differently under different reflow soldering profiles. The lower reflow temperature resulted in more reliable ACF joints by maintaining low contact resistance. By contrast, high contact resistance was found in assemblies treated with higher reflow. Under humidity aging (85°C/85%RH), bumpless chips proved to be unreliable due to corrosion mechanism. Moreover, ACF had shown degradation in chemical and physical properties, including modulus reduction, Tg depression, polymer hydrolysis, and surface swelling after exposing to humidity aging. The deterioration in reliability of aged ACF joint during reflow process was mainly caused by hydroscopic swelling-induced stress of ACF.
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Sun, Quan, Yebo Lu, Xiaobin Xu, Fengli Huang, and Chengli Tang. "Morphological evolution and migration behavior of silver thin films on flexible substrates during thermal cycle testing." Advances in Mechanical Engineering 10, no. 8 (August 2018): 168781401879596. http://dx.doi.org/10.1177/1687814018795961.
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To understand morphological evolution and migration behavior caused by stress migration and thermal fatigue of silver thin films on flexible substrates, bending tests were conducted with different bending angles for two types of thermal tests. Furthermore, the effect of stress migration and thermal fatigue on the electrical conductivity of the silver thin films was discussed. The experimental samples were silver thin films printed on flexible paper for these tests. In an ultra-low cycle thermal test, the electrical conductivity of a silver film decreased with increasing bending angle because of the occurrence of voids caused by stress migration. Meanwhile, a high-cycle thermal test caused cracks to form and caused further deterioration of the electrical conductivity owing to a combination of stress migration and thermal fatigue.
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Hruby, P., V. Bilek, L. Topolar, L. Kalina, M. Marko, F. Soukal, R. Dvorak, and T. Hercik. "Décalcification resistance of various alkali-activated materials." IOP Conference Series: Materials Science and Engineering 1205, no. 1 (November 1, 2021): 012015. http://dx.doi.org/10.1088/1757-899x/1205/1/012015.
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Abstract The resistance of alkali-activated materials (AAMs) to degradation processes, particularly the decalcification, was studied in this paper. The ground granulated blast furnace slag was alkali-activated using various activators with the same activator dosage 6% Na2O by slag weight (sodium hydroxide, sodium waterglass and sodium carbonate) and subjected to testing of decalcification resistance (immersion in 6M NH4 NO3) for 84 days. The reference samples were stored in water. The progress of degradation was studied using the phenolphthalein technique, mechanical properties testing (compressive and flexural strength), and dilatometry analysis or weight measurements. The results obtained were compared to the CEM III/A 32.5R. The significant loss of mass along with the deterioration of mechanical properties were observed for all binder types, still some of the AAMs showed better durability than the cementitious one.
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Hassani, Nacera, and Hocine Dehmous. "Experimental analysis of short concrete column under hygrothermo-mechanical accelerated aging." Frattura ed Integrità Strutturale 16, no. 60 (March 25, 2022): 363–79. http://dx.doi.org/10.3221/igf-esis.60.25.
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Concrete was considered to be very durable material for a long time. However many constructions have shown degradations during their service life. To ensure safety, stability and serviceability of civil engineering structures, understanding of deterioration processes and their effect on the residual structural load capacity is necessary. This paper is based on the experimental study of short prismatic concrete columns under the hygrothermo-mechanical accelerated aging. To investigate the effects of the exposure conditions on the strength of specimens, combined ultrasonic pulse velocity testing and compression loading testing was used. It can be observed from the results obtained in this work that the ultrasonic pulse velocity measurements agree well with the experimental results obtained from the compression loading testing. Results indicate that in first time, degradation of specimens occurs slightly. After that the degradation becomes notable. It also indicates that the degradation due to the combined effect of the hygrothermo-mechanical aging is higher than when we consider hygrothermal and mechanical process separately
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Grubic, Stefan, Jose Restrepo, Jose M. Aller, Bin Lu, and Thomas G. Habetler. "A New Concept for Online Surge Testing for the Detection of Winding Insulation Deterioration in Low-Voltage Induction Machines." IEEE Transactions on Industry Applications 47, no. 5 (September 2011): 2051–58. http://dx.doi.org/10.1109/tia.2011.2161972.
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A breakdown of the electrical insulation system causes catastrophic failure of the electrical machine and brings large process downtime losses. Preventive maintenance and online monitoring are some of the methods to improve the reliability and to reduce unscheduled downtime. One of the main reasons for the failure of the machine is the breakdown of the stator turn insulation. The offline surge test is the most commonly used offline test to assess the condition of the turn insulation. There is no online monitoring method that is applicable to low-voltage machines and has the same capabilities as the surge test. This paper introduces new concepts to implement an online surge test. The possibilities and limitations of the online surge test are presented, as well as the simulation and experimental results, to validate the concepts.
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Fayyadh, Moatasem Mohammed, and Hashim Abdul Razak. "DAMAGE IDENTIFICATION AND ASSESSMENT IN RC STRUCTURES USING VIBRATION DATA: A REVIEW." Journal of Civil Engineering and Management 19, no. 3 (June 14, 2013): 375–86. http://dx.doi.org/10.3846/13923730.2012.744773.
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Inspection of structural components for damage is essential to decision-making for the maintenance of such structures. There have been many studies to assess the reinforced concrete (RC) structural elements. However, the experimental approach is still based on the conventional static test, which is time-consuming, costly, has intensive equipment and labour requirements and causes major disruptions to the existing use. Modal testing provides an integrated approach, i.e. both local and global characteristics can be ascertained for structural assessment. Depending on the accessibility to damage elements, little or no disruption to the existing use is incurred during testing works. The approach towards structural assessment work provides not only a viable but also a robust, less expensive and powerful alternative to conventional techniques. This paper presents the background of the behaviour of the RC material at different loading and unloading conditions, in order to understand its effect on the modal parameters. The use of modal testing for support stiffness deterioration is highlighted and studies on the use of modal testing for classification of damage source are presented. Studies on the use of modal testing for detection of damage severity and location algorithms and procedures are also presented.
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Shelov, Eric, Naveen Muthu, Heather Wolfe, Danielle Traynor, Nancy Craig, Christopher Bonafide, Vinay Nadkarni, Daniela Davis, and Maya Dewan. "Design and Implementation of a Pediatric ICU Acuity Scoring Tool as Clinical Decision Support." Applied Clinical Informatics 09, no. 03 (July 2018): 576–87. http://dx.doi.org/10.1055/s-0038-1667122.
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Background and Objective Pediatric in-hospital cardiac arrest most commonly occurs in the pediatric intensive care unit (PICU) and is frequently preceded by early warning signs of clinical deterioration. In this study, we describe the implementation and evaluation of criteria to identify high-risk patients from a paper-based checklist into a clinical decision support (CDS) tool in the electronic health record (EHR). Materials and Methods The validated paper-based tool was first adapted by PICU clinicians and clinical informaticians and then integrated into clinical workflow following best practices for CDS design. A vendor-based rule engine was utilized. Littenberg's assessment framework helped guide the overall evaluation. Preliminary testing took place in EHR development environments with more rigorous evaluation, testing, and feedback completed in the live production environment. To verify data quality of the CDS rule engine, a retrospective Structured Query Language (SQL) data query was also created. As a process metric, preparedness was measured in pre- and postimplementation surveys. Results The system was deployed, evaluating approximately 340 unique patients monthly across 4 clinical teams. The verification against retrospective SQL of 15-minute intervals over a 30-day period revealed no missing triggered intervals and demonstrated 99.3% concordance of positive triggers. Preparedness showed improvements across multiple domains to our a priori goal of 90%. Conclusion We describe the successful adaptation and implementation of a real-time CDS tool to identify PICU patients at risk of deterioration. Prospective multicenter evaluation of the tool's effectiveness on clinical outcomes is necessary before broader implementation can be recommended.
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Dai, Quanmin, Guowei Mu, Fuwen Tan, Huidong Chen, Xianggang You, Yanxia Liu, and Guang Cheng. "The influence of aging time and moisture content on the tensile strength of transformer bushing insulating paper." AIP Advances 12, no. 11 (November 1, 2022): 115020. http://dx.doi.org/10.1063/5.0121821.
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The parameter of tensile strength for transformer bushing insulating paper occupies an important position in the structural design and life evaluation of transformer bushing. In order to precisely achieve the effect of aging time and moisture content on the tensile strength of transformer bushing paper, transformer insulating paper samples with a thickness of 0.13 mm were prepared for tensile strength and dielectric strength testing under different moisture contents and aging states. The results show that the tensile strength (MPa) of insulating paper decreases linearly in the range of 0–648 h under accelerated thermal aging at 130 °C. However, there is a more serious exponential decline in the tensile strength (MPa) of insulation paper with its moisture content is boosted. The moisture content in insulation paper is the most important factor for insulation paper deterioration in oil-impregnated paper insulation equipment, which could accelerate the end of insulation service life. The value of capacitance increment ΔC of the insulation paper samples displayed closely linear growth with a moisture content from 0.5% to 5.9%. Strictly controlling the moisture content by monitoring the ΔC value of transformer insulation paper is of significance for prolonging its service life.
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Zhou, Wensong, Shunlong Li, and Hui Li. "Damage Detection for SMC Benchmark Problem: A Subspace-Based Approach." International Journal of Structural Stability and Dynamics 16, no. 04 (March 28, 2016): 1640025. http://dx.doi.org/10.1142/s0219455416400253.
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A full-scale bridge benchmark problem was issued by the Center of Structural Monitoring and Control at the Harbin Institute of Technology. The data used in this problem were collected by an in situ structural health monitoring system implemented into a full-scale cable-stayed bridge before and after the bridge was damaged, which is very rare in structural health monitoring field. This benchmark problem will help to verify and/or make comparison of the condition assessment and the damage detection methods, which are usually validated by numerical simulation and/or laboratory testing of small-scale structures with assumed deterioration models and artificial damage. With respect to damage detection of girder, one of the benchmark problems, using the monitored and field testing acceleration data, this paper describes a damage detection method, based on a residual generated from a subspace-based covariance-driven identification method, to detect the damage, and give relative quantitative damage indexes. This method was applied on both two parts of the given benchmark problem, and then detailed discussions and results on this problem are reported in this paper.
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Kurakina, Elena, and Sergey Evtiukov. "Impact of static and dynamic loads of vehicles on pavement." E3S Web of Conferences 164 (2020): 03025. http://dx.doi.org/10.1051/e3sconf/202016403025.
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The present paper substantiates urgency of studies on early deterioration of pavement layers and on reasons entailing it. The aim was to investigate static and dynamic loads imposed on a road surface by vehicles in order to detect signs of early deterioration of pavement and understand its reasons. Certain tasks were set: to define diagnostic capacity for performing test works on road surface with the use of static and dynamic loading equipment; to carry out an elastic modulus analysis on the basis of static and dynamic loading tests performed; to assess strength properties of flexible pavement. The paper describes methods for determining strength properties of a road surface with the use of special static and dynamic loading equipment. The authors provide data on diagnostic capacity of tests of a pavement performed with the use of special testing equipment. The paper gives a list of potentials, advantages and fundamental features of the following units of equipment: apparatus for plate bearing tests, Dina-3M, UDN-NK, Dynatest apparatus. The main parameters of equipment for dynamic loading tests are provided. The results of both dynamic and static loading tests performed in Saint Petersburg and the Leningrad region are given. Deflection bowls and elastic modulus were determined. Coefficients of the dynamic elastic modulus being reduced to the static one were calculated. Strength properties of flexible pavement were assessed.
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Sokolović, Neda M., Milica Petrović, Ana Kontić, Suzana Koprivica, and Nenad Šekularac. "Inspection and Assessment of Masonry Arch Bridges: Ivanjica Case Study." Sustainability 13, no. 23 (December 2, 2021): 13363. http://dx.doi.org/10.3390/su132313363.
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The importance of masonry arch bridges as a traffic network element calls for a thorough analysis focused on both structural stability and loading capacity of these historical structures, considering the usage of these bridges in contemporary traffic conditions. This paper focuses on the analysis of longitudinal cracks in a single span masonry arch bridge to evaluate its influence on structural behaviour of the system. As longitudinal cracks do not necessarily present an inevitable collapse mechanism, analysis of the causes is crucial for evaluating the serviceability and functionality of the bridge investigated. The methodology is based on the following: literature review, observation of the stone bridge in Ivanjica, geological testing of the site, geophysical testing of the bridge, laboratory testing of mechanical characteristics of stone used for the bridge construction and biological analysis of the samples of implemented materials on the bridge. Finite element analysis of the bridge was conducted to define the causes of the longitudinal cracks. The 3D simulation model was based on the data collected through observation and experimental analysis. This paper provides extensive research on a single span masonry bridge, examining how different deterioration mechanisms, in conjunction, can lead to the appearance of cracks in masonry arch bridges and provide remedial measures accordingly.
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Hajšman, Jan, Ludmila Kučerová, and Karolína Burdová. "The Influence of Varying Aluminium and Manganese Content on the Corrosion Resistance and Mechanical Properties of High Strength Steels." Metals 11, no. 9 (September 13, 2021): 1446. http://dx.doi.org/10.3390/met11091446.
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The aim of this paper is to evaluate the influence of small variations in chemical composition on the corrosion resistance and mechanical properties of low-manganese and medium manganese high strength steels. Six different steels with manganese content varying from 1.5 to 4.0 wt.% and aluminium from 0.008 to 6.5 wt.% were subjected to the analysis. The other subjects for evaluation included the effect of aluminium as a replacement for silicon, niobium microalloying and the effect of heat treatment. The effect of non-metallic inclusions on localized corrosion initiation and propagation was also documented. Using potentiodynamic testing, exposure testing, tensile and impact testing, it was found that the improvement in corrosion resistance associated with increasing aluminium content is accompanied by a significant deterioration of the mechanical properties. Niobium microalloying and heat treatment was found to have no quantifiable impact on the anti-corrosion properties. The effect of aluminium content proved to be superior to the effect of nonmetallic inclusions in terms of determining the overall corrosion resistance of the experimental steels.
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Wang, Xiujuan, Zhihong Fu, Yao Wang, Renkuan Liu, and Lin Chen. "A Non-Destructive Testing Method for Fault Detection of Substation Grounding Grids." Sensors 19, no. 9 (May 2, 2019): 2046. http://dx.doi.org/10.3390/s19092046.
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The grounding grid is critical to the safety and stability of a power system. Corrosive cracking of the grounding conductor is the main cause of deterioration of grounding grid performance. Existing fault diagnosis methods for grounding grids are limited by the number and distribution of grounding leads, and some of them cannot be used for online detection. This paper proposes a grounding grid detection method based on magnetic source excitation. The measuring device consists of four coils, two horizontal excitation coils, and two vertical receiving coils. The secondary magnetic field signal is extracted from the primary field and the background field by properly positioning the coils, such that the measured signal can reflect the underground media more accurately. The measuring device of the method is portable, the measurement process is contactless with the grounding grid, and it is not limited by the grounding leads. Furthermore, it has a strong anti-interference ability and can realize online detection. It was proven by simulations and experiments that the proposed method has a higher measurement accuracy and stronger anti-interference ability when compared with existing methods. This paper also discusses the influence of various factors such as the number and the location of the breakpoints, the frequency of the excitation source, the soil resistivity, and stratification from the measurement data. It was proven that the method has high precision and a wide application range, and is important for guiding significance and reference value in engineering applications.
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Yoshida, Akihito, Linsheng Liu, Dong Tu, Shigenobu Kainuma, and Chao-Nan Xu. "Mechanoluminescent Testing as an Efficient Inspection Technique for the Management of Infrastructures." Journal of Disaster Research 12, no. 3 (May 29, 2017): 506–14. http://dx.doi.org/10.20965/jdr.2017.p0506.
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This paper reports on the mechanoluminescence inspection technology we have developed and its applications. The inspection technology is expected to identify deterioration and damage, such as fatigue cracks developed on steel members of steel structures, using particular mechanoluminescence (ML) phenomenon. In field testing at an urban highway bridge currently in service, fatigue cracks in steel box girders were successfully detected using the proposed technology. In addition, using a conventional crack detection method known as magnetic particle inspection (MT), similar results were obtained in terms of crack judgment, suggesting that the reliability of the ML method is equivalent to that of the MT method. An advantage of the ML inspection method is that it does not require removing corrosion protection coating, saving labor that is necessary in the MT method. The field testing also examined the possibility of evaluating precautionary measures (repair) as another application of the ML technique. As a result, the ML technique quantitatively evaluated that detected cracking had been properly repaired (removed). It is expected that the ML technique will contribute to effective maintenance and management of infrastructures from the perspective of preventive maintenance.
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SLOAN, JOHN C., TAGHI M. KHOSHGOFTAAR, BASSEM ALHALABI, and PIERRE-PHILIPPE BEAUJEAN. "STRATEGY AND APPLICATION OF DATA-DRIVEN TESTING OF AN OCEAN TURBINE DRIVETRAIN." International Journal of Reliability, Quality and Safety Engineering 18, no. 06 (December 2011): 555–71. http://dx.doi.org/10.1142/s021853931100424x.
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An ocean turbine generator will be subject to variations in water current velocity at one end and resistive load at the other. Measurements acquired during bench testing of the turbine's drivetrain can be used to predict the effect of these variables on the turbine during deployment. This paper outlines an ongoing series of tests involving vibration data captured at various velocities and loads. This data is analyzed to detect the machine's state using two approaches. In the first approach, machine learning techniques are used to discern between states given adjacent values for velocity or load. The purpose of that approach is to assess a learner's ability to draw the fine distinctions needed for subsequent fault identification. The second approach computes a power spectrum for each velocity and load combination over enough trials as to construct an operating envelope. The purpose of that approach is to identify as abnormal, incoming data having parts of its spectrum that fall outside that envelope. A case study applies each approach to baseline data and data for a deterioration scenario. The rationale behind each approach, their assumptions, and their limitations are also discussed.
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Topolář, Libor, Hana Šimonová, Pavel Rovnaník, and Pavel Schmid. "The Effect of the Carbon Nanotubes on the Mechanical Fracture Properties of Alkali Activated Slag Mortars." Applied Mechanics and Materials 617 (August 2014): 243–46. http://dx.doi.org/10.4028/www.scientific.net/amm.617.243.
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New nanomaterials such as carbon nanotubes and nanofibres considerably improve performance of current building materials and they can contribute to new application facilities. Alkali activated slag is a material having a great potential to be used in practice. The main drawback of this material is a high level of autogenous and especially drying shrinkage, which causes a deterioration of the mechanical fracture properties. The aim of this paper is introduce the effect of carbon nanotubes admixture on the microstucture and mechanical performance of alkali activated slag mortars. The three-point bending tests of specimens with central edge notch were performed. Method of acoustic emission was used during this testing.