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Texture features analysis on micro-structure of paste backfill based on image analysis technology; 基于图像识别技术的膏体微观结构纹理特征分析;
摘要： The strength of cement-based materials, such as mortar, concrete and cement paste backfill (CPB), depends on its microstructures (e.g. pore structure and arrangement of particles and skeleton). Numerous studies on the relationship between strength and pore structure (e.g., pore size and its distribution) were performed, but the micro-morphology characteristics have been rarely concerned. Texture describing the surface properties of the sample is a global feature, which is an effective way to quantify the micro-morphological properties. In statistical analysis, GLCM features and Tamura texture are the most representative methods for characterizing the texture features. The mechanical strength and section image of the backfill sample prepared from three different solid concentrations of paste were obtained by uniaxial compressive strength test and scanning electron microscope, respectively. The texture features of different SEM images were calculated based on image analysis technology, and then the correlation between these parameters and the strength was analyzed. It was proved that the method is effective in the quantitative analysis on the micro-morphology characteristics of CPB. There is a significant correlation between the texture features and the unconfined compressive strength, and the prediction of strength is feasible using texture parameters of the CPB microstructure.
关键词： cement paste backfill,unconfined compressive strength,Tamura texture,microstructure,quantitative analysis,texture feature,GLCM feature
更新于2025-09-23 15:23:52
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Mitigating the electromagnetic radiation by coupling use of waste cathode-ray tube glass and graphene oxide on cement composites
摘要： With technological development, the rapid growing numbers of electronic devices generate severe electromagnetic interference (EMI) and radiation to human environment. In this study, the coupling effect of graphene oxide (GO) addition (up to 0.10 wt.% of cement) and waste cathode-ray tube (CRT) glass replacement for fine aggregates (30 and 60 wt.%) in cement-based composites on mitigating EMI was studied. The electric permittivity obtained using a decoupling method was applied for evaluating the EMI shielding capacity of cement-based composites, while direct current (DC) electrical resistance measurement is conducted using four-probe method. The DC electrical resistivity of specimens increases insignificantly with increasing in GO content, but remarkably with increasing CRT glass content from 30 to 60 wt.%. The 60 wt.% replacement of waste CRT glass with 0.1 wt.% GO addition increases the relative permittivity by about 50% and 200% when the frequency is in the ranges of 104–5 × 106 Hz and 101–103 Hz, respectively. It is concluded that a significant increase in the permittivity can be obtained owing to the synergetic interaction between waste CRT glass and GO. The improvement in the EMI shielding ability of cement-based composites not only enables the applications of these composites in mitigating electromagnetic pollution, but also promotes large-volume recycling of toxic waste CRT glass.
关键词： Permittivity,Waste CRT glass,Cement composite,Graphene oxide,Electromagnetic interference
更新于2025-09-23 15:23:52
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Hydration accelerator and photocatalyst of nanotitanium dioxide synthesized via surfactant-assisted method in cement mortar
摘要： To develop TiO2-based cement materials, the effect of TiO2 on the cement hydration and photocatalytic reaction should be investigated. The phase, size and shape of TiO2 are important factors for better understanding its application in cement. TiO2 nanoparticles were synthesized by a surfactant-assisted, reverse micelle method to control phase, size and shape by three selected surfactants namely: sodium dodecyl sulfate (SDS), cetyl trimethylammonium bromide (CTAB) and TritonX-100. The synthesized TiO2 nanoparticles were characterized by XRD, SEM and TEM for observation of phase, size and shape. The modified micro structures of admixed cements with the different synthesized TiO2 nanoparticles incorporated were also examined by SEM. Particularly, the hydration process and photocatalytic reaction of the cement mixture were evaluated by heat flow calorimetry and methylene blue (MB) degradation, respectively. Results showed that anatase-rich and smaller size TiO2 nanoparticles provided accelerated cement hydration and the ability to degrade MB photocatalytically at the surface of admixed-TiO2 cement.
关键词： Surfactant-assisted method,Photocatalytic activity,Hydration,Cement,Titanium dioxide nanoparticle
更新于2025-09-23 15:22:29
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Exact impact response of multi-layered cement-based piezoelectric composite considering electrode effect
摘要： Multi-layered cement-based piezoelectric composites could enable accurate real-time detection of the concrete structure deformation induced by impact load. An analytical method for quantifying the impact response of the multi-layered cement-based piezoelectric composite is established based on the piezo-elasticity, and a general transfer matrix description for the composite with any number of layers is derived. The motion of the composite is decomposed into natural modes according to its physical significance of vibration modes. The mechanical and electrical solutions are obtained via the mode summation method and the virtual work principle. In order to give a clear demonstration, some numerical simulations are conducted to verify the validity of the theoretical analysis. Moreover, the current analytical method considers the electrode as an extra layer and evaluates the effect of its thickness and material on the performance of the multi-layered cement-based piezoelectric composite. It can be seen that the mathematical model presented in this article provides a rigorous tool for the analysis of the multi-layered cement-based piezoelectric composite and therefore could benefit the design of certain types of smart devices under impact load.
关键词： multi-layered cement-based piezoelectric composite,Exact impact response,piezo-elasticity,electrode effect
更新于2025-09-23 15:21:01
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Pulmonary Bone Cement Embolism: CT Angiographic Evaluation with Material Decomposition Using Gemstone Spectral Imaging
摘要： We report a case of pulmonary bone cement embolism in a female who presented with dyspnea following multiple sessions of vertebroplasty. She underwent spectral CT pulmonary angiography and the diagnosis was made based on enhanced visualization of radiopaque cement material in the pulmonary arteries and a corresponding decrease in the parenchymal iodine content. Here, we describe the CT angiography findings of bone cement embolism with special emphasis on the potential benefits of spectral imaging, providing additional information on the material composition.
关键词： Bone cement,Spectral imaging,Pulmonary embolism,Dual-energy CT
更新于2025-09-23 15:21:01
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Groove Depth Detection Method Base on the Line Laser Vision Measurement on Cement Concrete Pavement
摘要： The groove depth has a decisive influence on the anti-sliding performance of cement concrete pavement, and it also plays an important role on the noise of cement concrete pavement. Aiming the shortcomings of traditional measurement methods of groove depth detection on the cement concrete pavement, a measurement method base on the structure light vision model was proposed. This method was realized by that the groove depth was obtained by 3D coordinate of the light strip according to the camera model and the structure light plane equation. A new algorithm based on double 2D plane pane target was proposed as the key step of this method.
关键词： groove depth,line laser vision,structure light vision model,cement concrete pavement
更新于2025-09-23 15:19:57
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Klinische Verbesserung und Wirtschaftlichkeit nach CT-gesteuerter Radiofrequenzsakroplastie und Zementsakroplastie – ein prospektiver randomisierter Methodenvergleich
摘要： Introduction The objective of this study was a comparative analysis of cement augmentation by means of RFS and CSP with regard to outcome and cost-effectiveness. Patients and Methods CT-guided cement augmentation was performed on 100 patients with a total of 168 non-dislocated insufficiency fractures, 50 patients being treated with RFS and 50 patients with CSP. Leakages were detected by CT. Pain intensity was determined on a VAS before and after the intervention. The patients? self-sufficiency was assessed using the Barthel index. Patients were asked about any complications and their level of satisfaction. Costs incurred for carrying out the procedure were compared with the respective reimbursements received. Results Both procedures were technically fully feasible. No leakages were found in the RFS group, as opposed to 8.1 % asymptomatic leakages in the CSP group. The mean value for pain before intervention was 8.8 in the RFS group and 8.7 in the CSP group. On the second postoperative day, there was a significant pain reduction with a value of 2.4 for both groups, which remained more or less constant over the follow-up period. The Barthel index increased significantly from an average of 30 before the intervention to 80 on the fourth postoperative day and 70 after 24 months. No differences were found between the two procedures with regard to pain, improvement in functional status and satisfaction. Taking into account the state-wide base rate used for calculating reimbursement, 3,834.75 € remained for RFS and 5,084.32 € for CSP. Conclusion RFS and CSP are minimally invasive procedures that achieve equally good and sustained pain reduction, leading to markedly improved self-sufficiency of the patients. With regard to possible cement leakages, RFS is the safer method. A profit can be generated with both techniques.
关键词： radiofrequency sacroplasty,pain therapy,insufficiency fracture,sacrum,cement sacroplasty
更新于2025-09-19 17:15:36
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Rapid determination of mercury in dust emission using Cold Vapour Inductively Coupled Plasma Optical Emission Spectrometer (CV ICP OES)
摘要： Mercury emissions generated by the human activities were ranged between 60% and 90% from total mercury content determined in some industrialised regions. It is well known that urban dust has adverse health effects, being related to respiratory diseases. In this study, Cold Vapour Inductively Coupled Plasma Optical Emission Spectrometer (CV ICP OES) was optimised, validated, and applied in routine analysis for the determination of vapour mercury in dust emission samples collected from different Egyptian cement plants. The estimated detection limit, practical quantification limit, linearity (linear dynamic ranges and method linearity), accuracy (trueness and precision), and measurement uncertainty parameters were studied under optimised (CV ICP OES) conditions. The method showed that the estimated detection limit was found to be equal to 0.12 μg/L, and the quantification limit was found to be equal to 0.5 μg/L. The mean recoveries ± standard deviations at different levels were varied between 88.60 ± 8.18 and 110.20 ± 5.93% with a coefficient of variation expressed as relative standard deviation ranged from 0.64 and 7.25%. The method trueness was confirmed by using four different certified references materials purchased from Food Analysis Performance Assessment Scheme (FAPAS) and all obtained results were within satisfactory ranges and had acceptable recovery and Z-score values. The method precision, in terms of relative standard deviation (RSD), was being below 7.74%. The method uncertainty expressed as expanded uncertainty was found to be ≤ 16.11%. The results obtained make the method suitable for accurate determination of vapour mercury in dust emission samples at low concentration. The validated method was used for the determination of mercury in fifty-eight dust emissions samples and the results were compared with the maximum limit stated by European standard on the incineration of waste.
关键词： CV ICP OES,cement plants,mercury,Method validation,Egypt
更新于2025-09-19 17:13:59
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High-Power Fiber Laser Cutting for 50-mm-Thick Cement-Based Materials
摘要： This experimental research highlights the applicability of laser cutting to cement-based materials using multimode ?ber lasers. A 9 kW multimode ?ber laser is used, and the experimental variables are the water-to-cement ratio, laser speed, and material compositions such as cement paste, cement mortar and ultra high performance concrete (UHPC). The laser cutting performance on the cement-based materials is investigated in the downward laser direction. The kerf width and penetration depth of the cement-based materials are quantitatively evaluated with the parameters in the surface and cross section of the specimens after the laser cutting. Moreover, the material removal zone of each specimen is compared in terms of the penetration shapes in the cross-sectional view. Based on experimental observations, the interaction mechanism between the laser and cement-based materials is proposed.
关键词： laser cutting,elliptical hole,cement-based material,multimode ?ber laser
更新于2025-09-19 17:13:59
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Microstructural Characteristics of Cement-Based Materials Fabricated Using Multi-Mode Fiber Laser
摘要： Cement-based materials are the most prevalent construction materials, and the conventional cutting techniques are still mostly used for fabricating the materials. However, these conventional cutting methods could generate undesirable micro-cracks and remove unintentional structural sections. This experimental study aims to evaluate the e?ects of the new fabricating method using laser on the microstructural characteristics of the cement-based materials. The experimental variables are laser cutting speed, water to cement ratio and material compositions. In order to compare the microstructure before and after the laser interaction, the microstructure of the cut surface is observed through scanning electron microscopy/energy dispersive X-Ray (SEM/EDX). After the laser interaction, the Material Removed Zone (MRZ) and Heat A?ected Zone (HAZ) are observed on the cut surface. In MRZ, it is found that the glassy layer is thickened by an increasing amount of silicate-based materials in cement-based materials. In addition, it concluded that the amount of silicate-based material mixed in the cement-based materials a?ects the laser cutting quality.
关键词： microstructure,laser cutting,cement-based materials,multi-mode ?ber laser,SEM/EDX analysis
更新于2025-09-19 17:13:59