Test Methods Research Articles

Consolidating Lime Mortar with Nanolime: The Effect of the Ethanol:Water Ratio

ABSTRACT Over the last twenty years, more research has been conducted on the application of nanolime as a consolidant. However, a limitation in consolidation with nanolime is the back-migration of the product to the absorption surface during the drying phase, resulting in insufficient product deposition in depth. In this paper, a solvent composition is adapted to the substrate properties to examine the theory that a nanolime with low kinetic stability should be applied to prevent back-migration to the absorption surface for a substrate with large pore size. The common solvent composition of 100% ethanol has a kinetic stability considered too high. Nanolime dispersions (CaLoSiL® E 20 g/L) with different ethanol:water (100:0, 95:5, 90:10, 80:20) ratios were tested on lime mortar samples. The treated samples were subjected to several test methods to evaluate the effectiveness of the consolidation treatment. After comparing the results, the theoretical propositions were substantiated: a back-migration was noticeable in samples treated with the nanolime containing 100% ethanol, while no back-migration was observed in the other solvent compositions. Samples treated with a nanolime dispersion with the addition of 10% deionised water showed promising results regarding mechanical strength, product deposition over the entire depth profile of the sample, and porosity properties.

Determination on Effective Drainage Radius of In-Seam Borehole Based on Gas Content Test and Numerical Simulation Calculation Method.

In order to accurately and efficiently determine the effective drainage radius of the in-seam borehole, the advantages and disadvantages of the current effective drainage radius test methods are analyzed, and the method of combining the gas content field and numerical simulation calculation is proposed to accurately determine the effective drainage radius of the borehole, which is applied in the mine. The results show that the method combining gas content test and numerical simulation calculation has the advantages of a short measurement period and advanced means. The effective drainage radius of the borehole increases rapidly at the initial stage of gas drainage and then gradually slows, eventually reaching a limit value. The relationship between the effective drainage radius and drainage time follows a Langmuir function relationship. When the drainage time exceeds 300 days, the effect of the drainage time on the effective drainage radius becomes relatively small. The average error between the numerical simulation results of effective drainage radius and the field verification results of gas content is 2.2%, which validates the rationality of the constructed coal seam gas-solid coupling model. The research can provide theoretical references for accurately determining and reasonably laying out the effective drainage radius of the bedding borehole in the mining seam of the coal mine, which is of great practical significance for the safety production of the mine.

OpenHW3 – An open-source, low-cost temperature-controlled orbital shaker

The current lack of standardized testing methods to assess the binding isotherms of ions in cement and concrete research leads to uncontrolled variability in these results. In this study, an open-source and low-cost apparatus, named OpenHW3, is proposed to accurately measure the binding isotherms of ions in various cementitious material systems. OpenHW3 provides two main options, a temperature-controlled orbital shaker, as well as an option to retrofit a commercial orbital shaker for temperature control. The effectiveness of these device options is validated via comparison with conventional binding isotherms experiments. The binding isotherm results were comparable to conventional Waterbath shakers, while providing more reliable results compared to horizontal commercial shakers. It also provided accurate temperature control between 25 °C and 75 °C. The results here are critical for allowing open access to scientific equipment, and providing high-quality binding isotherm data for reliable service life models of urban infrastructure assets throughout the world.

Tensile constitutive relationship of UHPFRC from crack hinge based inverse analysis of notched beams

The structural applications of ultra-high performance fiber reinforced concrete (UHPFRC) in the construction industry can be promoted if proper constitutive models can be established for design. The various tension test methods for UHPFRC are being adopted to develop a complete stress-crack width or strain response for design. This study aims to understand the fracture behavior of UHPFRC by testing notched beams under a three-point bending configuration. This testing method helps in quality control checks and obtaining complete tension stress-crack opening behavior that can be used for design. The tensile stress-crack width response of UHPFRC is obtained using the load-CMOD response. The variables considered in this study are the volume fraction of fibers (1 % and 2 %), types of steel fibers (straight, combination of straight and hooked ended), and different cross-section dimensions (100×100×500 mm and 75×75×500 mm). A crack hinge-based inverse analysis method is used for UHPFRC to obtain the complete tensile stress-crack opening response. Stress-strain relations from inverse analysis and direct tension stress-crack opening results are compared and found to be similar. A data-driven tension stress-crack opening response UHPFRC is verified by simulating the girder's response using nonlinear finite element analysis (NFEA). Thus, the proposed inverse analysis can be used to obtain the multi-linear tensile stress-crack opening response which is adequate for capturing the structural response.

The Method and Experiment of Detecting the Strength of Structural Components Utilizing the Distributed Strain of Sensing Optical Fibers Demodulated by OFDR.

Defects occurring during the welding process of metal structural components directly affect their overall strength, which is crucial to the load-bearing capacity and durability of the components. This signifies the importance of accurate measurement and assessment of weld strength. However, traditional non-destructive testing methods such as ultrasonic and non-contact camera inspection have certain technical limitations. In response to these issues, this paper analyzes the detection principle of weld strength, revealing that weld defects reduce the effective area of the structural bearing section and cause stress concentration around them. Through repeated experimental data analysis of samples, strain distribution data along the one-dimensional direction caused by defects such as slag inclusion and porosity were obtained. Experimental results show that this method can identify defect types in welds, including slag inclusion, porosity, and unevenness, and accurately measure the location and size of defects with a precision of 0.64 mm, achieving qualitative analysis of weld defects. Additionally, by deploying distributed optical fiber sensors (DOFS) at different vertical distances along the weld direction, the propagation law of stress induced by different types of weld defects on samples was thoroughly analyzed. This further validates the advantages of this method in weld strength detection, including high spatial resolution, high sensitivity, and non-destructive measurement.

Determining the effects of timber strength and wood species on the mechanical properties of CLT using non-destructive and destructive methods

ABSTRACT This study aimed to determine the effects of production parameters such as wood species and timber strength classes on some mechanical properties of CLT panels using both non-destructive and destructive methods. Additionally, the study compared the strength values obtained from non-destructive and destructive testing methods on CLT panels and elucidated the relationship between them through regression analyses. CLT panels were produced using spruce and alder timbers, as well as hybrid panels formed from combinations of these two wood species. According to the TS EN 338 standard, the C and D strength classes of the timbers were determined non-destructively using an acoustic testing device. Among the timbers whose strength classes were determined, a total of 6 different strength classes were selected for spruce and alder. The bending strength, modulus of elasticity, and screw withdrawal force tests were performed on the CLT panel groups both non-destructive and destructive. As a result of the regression analyzes, the determination coefficient (R2) between non-destructive screw withdrawal force and destructive bending strength values varied between 0.6135–0,9997. Moreover, the R2 value calculated between non-destructive and destructive modulus of elasticity values for CLT panels was found to be between 0.7076–0.9997.

Crack Detection Method for Wind Turbine Tower Bolts Using Ultrasonic Spiral Phased Array.

High-strength bolts are crucial load-bearing components of wind turbine towers. They are highly susceptible to fatigue cracks over long-term service and require timely detection. However, due to the structural complexity and hidden nature of the cracks in wind turbine tower bolts, the small size of the cracks, and their variable propagation directions, detection signals carrying crack information are often drowned out by dense thread signals. Existing non-destructive testing methods are unable to quickly and accurately characterize small cracks at the thread roots. Therefore, we propose an ultrasonic phased array element arrangement method based on the Fermat spiral array. This method can greatly increase the fill rate of the phased array with small element spacing while reducing the effects of grating and sidelobes, thereby achieving high-energy excitation and accurate imaging with the ultrasonic phased array. This has significant theoretical and engineering application value for ensuring the safe and reliable service of key wind turbine components and for promoting the technological development of the wind power industry.

Development of a Highly Sensitive Electrochemical Detection of Salivary Glucose and pH Sensors Based on Glucose Oxidase Using Interdigitated Microelectrodes

The use of electrochemical nanosensors has seen a significant uptick in recent years, largely due to the improved chemical and physical properties that result from the modification of nano or microelectrode devices with nanomaterials.[1] These electrodes play a crucial role in enhancing electrochemical-based nanosensors, offering benefits such as a higher signal-to-noise ratio, lower detection limits, cost-effectiveness, ease of fabrication, and the ability to achieve steady-state currents. The interest in electrochemical nanosensors is considerable, given their broad application spectrum, which includes areas like animal health, human health, environmental monitoring, and bioprocess monitoring.[2] The focus of this research is the development of on-chip salivary glucose and pH sensors that are integrated on silicon wafers. These sensors are specifically designed to identify two frequently occurring bovine diseases: bovine respiratory disease (BRD) and scour. Both of these diseases are highly contagious, often resulting in fatal outcomes for calves, and cause economic losses amounting to millions of euros across Europe. Therefore, early detection of BRD and scour is essential to prevent, oversee, or delay the progression of the disease and its related complications. However, the current methods of blood glucose testing for calves have a significant disadvantage, as they require regular invasive blood sampling. Encouragingly, the analysis of saliva has surfaced as a non-invasive and convenient alternative for monitoring glucose levels in calves with above-mentioned disease.[3] Thus, it is necessary to develop a highly sensitive electrochemical nanosensor for early detection of BRD and scour by using biomarkers (glucose, pH) in a calf's saliva. The proposed electrochemical nanosensor is based on a micro fabricated device that integrates a silicon microelectrode, reference electrode, and counter electrode with six individual sensor that can be used for the detection of six different biomarkers i.e. glucose, pH, lactate, electrolytes, etc. The sensing mechanism is based on the measurement of changes in current that occur because of glucose and pH interactions with the modified silicon surface. The sensors are designed to detect small changes in glucose and pH concentrations that can be indicative of the onset of BRD and scour. The main advantage of the proposed electrochemical nanosensor is its ability to provide rapid and accurate detection of BRD and scour in calves. Early detection of these diseases can significantly improve treatment outcomes and reduce the risk of transmission to other animals. In addition, the low cost and ease of fabrication of these sensors make them an attractive option for large-scale deployment in agricultural settings. In conclusion, the development of on-chip electrochemical nanosensors for the early detection of bovine respiratory disease and scour by using saliva as a medium is a promising approach for improving animal health and reducing economic losses. The proposed sensors offer high sensitivity, low cost, and easy fabrication, making them an attractive option for widespread deployment in agricultural settings. Future research can focus on optimizing the sensor design for improved performance and expanding the range of biomarkers that can be detected.This work represents the microfabrication and characterization of gold interdigitated electrodes (IDE) on silicon using standard microfabrication methods i.e., lithography and etching techniques. The sensor have six individual working electrodes (WEs) along with on-chip gold counter and platinum reference electrodes and can be modified individually for glucose and pH sensor. A two-step electrodeposition process was carried out for platinum platting thus incorporating glucose oxidase (GOx) onto a platinum-modified gold IDE with an o-phenylenediamine (o-PD). The enzymatic based nanosensor demonstrated a linear reduction response to wider range of glucose from 0.02-7mM using chronoamperometric measurements in artificial saliva (Figure 1a,b). In addition, real calf samples have been used to detect the glucose level in calf saliva and compared with commercial glucometer (Figure 1c). Furthermore, at gold IDE, the sensor exhibits linear responses for pH ranging from pH 5-8 using cyclic voltammetric analysis (Figure 1d,f).

The Self-Powered Thermoelectric System Driving an Electric Field for Raman-Spectrum Glucose Quantitative Analysis

For a long time, blood glucose monitoring has been a challenging issue in the field of medicine. Although it is possible to visit a hospital for regular blood tests to track blood sugar concentration, the physiological reactions triggered by blood collection might lead to feeling weak, dizzy, or even vomiting. Therefore, especially for diabetic patients, they need to frequently monitor their blood sugar concentration in their daily lives to ensure their health. Currently, the primary methods for blood glucose testing still rely on invasive techniques, such as using fingertip glucose meters and other methods which require skin puncture to obtain blood samples. Although these methods provide a quick assessment of current blood glucose concentration, they come with the pain and discomfort of blood collection process and the potential risk of infection. As a result, in recent years, many researchers have been dedicated to developing non-invasive blood glucose monitoring methods. However, accurately measuring glucose concentration inside the human body remains a challenging task. One of the primary issues is the presence of strong noise and background noise. To avoid this challenge, we have developed an innovative detection platform that is combines surface-enhanced Raman spectroscopy (SERS) and external electric field sensing technology. With the electromagnetic effect, we add external electric field in our platform to excite more the surface plasmon resonance. By using this method, we can achieve signal amplification to detect lower concentrations of glucose. Now, we can detect down to 0.001mM of glucose. We also exhibit self-powered electric field system, using the flexible themoelctric device to combine our platform. By the property of self-powered, we success to create a self-powered electric field system. We focus on driving themoelectric through the temperature different between body temperature and environment. The approach is aimed at generating power from the human body, providing a self-powered thermoelectric system for Raman-spectrum glucose sensors. This innovative approach holds promise for advancing non-invasive blood glucose monitoring and benefiting a larger population of diabetes patients in the future.

Electrochemical Quantification of Tobramycin Retention in Pseudomonas Aeruginosa as Antimicrobial Susceptibility Indicator

The emergence and spread of bacterial resistance to antibiotics has developed into one of the most challenging threats to public health. Antibiotic susceptibility tests (ASTs) for bacterial infections are now essential, because they provide guidance for physicians in the selection of antibiotics, to which bacteria will respond. Most current AST methods require long periods of time, because of bacterial growth and incubation, leading to a prolonged and overuse of broad-spectrum antibiotics. Thus, there is a growing demand for methods and technologies that enable rapid antibiotic susceptibility assessment. Due to advantages related to cost-effectiveness, rapid response time and high sensitivity,electrochemical detection methods are promising analytical tools that can successfully quantify antibiotic uptake and retention in clinically relevant bacterial strains. This study presents the electroanalytical quantification of tobramycin (TOB) retention in susceptible and resistant bacterial strains of Pseudomonas aeruginosa. The electrochemical behavior of TOB was characterized by voltammetry, identifying redox potentials, the current dependence on pH conditions, and the detection limit at unmodified glassy carbon electrodes. The presented methodology was able to distinguish between susceptible and resistant bacterial strains, and is also capable of identifying varying degrees of resistance against TOB. The presented approach detects the immediate interaction of bacteria with an antibiotic, without the need of complex and cost-intense equipment related to genomic testing methods

Spatiotemporal Variation Characteristics and Driving Factors of Cultivated Land NPP in the Shandong Area Around the Bohai Sea

The Bohai Rim Plain is an important grain-producing area in China. The cultivated land resources have great potential for production, but there are many influencing factors. Understanding the spatiotemporal change characteristics and driving factors of the net primary productivity （NPP） of cultivated land vegetation in this region is of great significance to improve the regional cultivated land production conditions, excavate and enhance the production capacity of cultivated land, and ensure national food security. In this study, Theil-Sen Median trend analysis, Mann-Kendall significance test, Hurst index, and other methods were used to explore the spatiotemporal change characteristics, stability, and sustainability of regional cultivated land NPP. The influence of driving factors on the spatial heterogeneity of cultivated land NPP was analyzed by using optical parameters-based geographical detectors. The results showed that： ① From 2001 to 2019, due to the expansion of construction land during industrialization and urbanization, the cumulative decrease in the area of cultivated land in the Shandong area around the Bohai Sea was 2 004.51 km2. ② During the selected research period, the interannual variation of average cultivated land NPP showed a fluctuating and increasing trend. In terms of spatial distribution, the NPP of cultivated land was bounded by the Dongying District, with the spatial heterogeneity in the north being significantly lower than that in the south. ③ The area with increasing NPP of cultivated land accounted for 88.06% of the total area of cultivated land, mainly with low and medium fluctuations. The NPP of cultivated land will maintain an overall sustained trend of increase across the region in the future. ④ The average annual relative humidity study area had the strongest explanatory power for the spatial variability of NPP in cropland, with a q-value of 0.26, followed by surface soil salinity and subsoil salinity, with q-values greater than 0.2. The interactions between the different drivers all showed either nonlinear enhancement or bifactorial enhancement. The results of this study will help to reveal the characteristics of the changes in cultivated land production capacity and its driving forces in the Bohai Sea region and also provide a theoretical basis for the ecological protection and sustainable development of the region.

Non-contact defect imaging of carbon fiber composites using laser excited acoustic shearography

The performance of carbon fiber reinforced polymer (CFRP) composites is significantly affected by the presence of subsurface defects, which originate from manufacturing processes or during operations. Although many non-destructive testing (NDT) methods have been employed to inspect CFRP materials and structures, the existing techniques are often time-consuming and sometimes require contact measurement. This paper presents a non-contact and rapid inspection method utilizing laser-excited acoustic shearography to detect subsurface defects in CFRP composites. In this method, a pulsed nanosecond laser is used to generate ultrasonic waves through thermoacoustic effect, and a shearography sensor is used to image the full-field wave-defect interactions. It is found that the proposed method can efficiently image various subsurface defect sizes in a non-contact way. The identified defects were validated through comparison with X-ray computed tomography (XCT).

A comparative study of constitutive models for EPS foam under combined compression and shear impact loading for helmet applications

Virtual testing of helmets using finite element (FE) analysis can be a valuable tool during product development. Still, its usefulness is limited by the quality of the constitutive model of the energy-absorbing material, usually foam. Built-in constitutive models in commercial FE software are developed for traditional linear compression loading. However, modern oblique test methods load the foam in combined compression and shear. Therefore, we aim to evaluate to what extent built-in constitutive models in commercial FE software can represent Expanded Polystyrene (EPS) foam during combined compression and shear loading (CCSL). EPS foam is tested experimentally in a newly developed test rig for CCSL (V-test). The response is compared against the simulation using three different constitutive models available in LS-DYNA (M83, M126, and M181). The models are assessed by their ability to capture the correct response, focusing on how well the continuum models can capture the phenomenological events seen in the experiments. The results show that the models perform well in compression, as expected. However, we point out limitations in the shear response and significant limitations in the unloading response, both important for oblique helmet testing. Due to these limitations, we conclude that the existing models are inadequate for accurately simulating oblique helmet impacts. There is a clear need to develop and implement new constitutive models focused on capturing CCSL including the unloading. Additionally, frictional sliding was found to substantially influence the measured response in the V-test method. Minimizing interface sliding is therefore critical for isolating the material behavior.

Multiprobe Amplification (MPA) with Melting Curve Analysis: A Highly Stable and Cost-Effective Platform for the Simultaneous Detection of Eight Potential Bacterial Bioterrorism Agents in Complex Samples.

We aimed to develop an efficient detection platform that can identify a larger number of suspicious samples in a single test, saving time, manpower, and material costs, and providing vital support to the public health system in coping with the current challenging and dynamic bioterrorism threat landscape, particularly in regions of turmoil and conflict. We have successfully developed a high-throughput, multitarget fluorescent array detection platform by effectively combining integrating multiprobe amplification (MPA) with melting curve analysis. Specifically, we have established reliable laboratory testing methods for eight highly pathogenic bacteria, including Bacillus anthracis, Yersinia pestis, Brucella spp., Burkholderia pseudomallei, Francisella tularensis, Vibrio cholerae, Salmonella typhi, and Staphylococcus aureus. Our method achieves sensitive and specific simultaneous detection of eight target bacteria in one well by optimizing the reaction conditions of MPA. In the assessment of 192 simulated environmental samples, both positive and negative coincidence rates were 100.00%. Among 48 simulated clinical samples, the positive coincidence rate reached 97.73%, while maintaining a perfect negative coincidence rate of 100.00%. Moreover, the detection platform holds immense potential for attaining a more comprehensive bioterrorism screening, and its high cost-effectiveness enables the provision of diverse and adaptable diagnostic methods for public health quarantine in underdeveloped countries and regions.

The impact of homocysteine on patients with diabetic nephropathy: a mendelian randomization study.

Homocysteine (Hcy) has been associated with an increased risk of diabetic nephropathy (DN) in patients, but there is still controversy. This study aims to investigate the causal relationship between plasma Hcy and DN. A Mendelian randomization (MR) study using data from 2 samples was employed to infer causal relationships. The aggregated genetic data associated with Hcy was derived from the largest genome-wide association study (GWAS) to date, involving 44,147 individuals of European ancestry.Data on SNP-diabetic nephropathy, creatinine, and urea nitrogen were obtained from the IEU GWAS database. The analysis method employed a fixed-effect or random-effect inverse variance-weighted approach to estimate effects.Additional analysis methods were used to assess stability and sensitivity. The potential for pleiotropy was evaluated using the MR-Egger intercept test. Using 12 SNPs as instrumental variables, two-sample MR analysis revealed no evidence of a causal relationship between genetically predicted plasma Hcy levels and diabetic nephropathy, as well as creatinine and blood urea nitrogen levels. This finding is consistent with the results obtained from other testing methods. Two-sample Mendelian Randomization analysis found no evidence of a causal relationship between plasma homocysteine levels and diabetic nephropathy, creatinine, or urea.

Skipped wells and scientific error during fosfomycin agar dilution and broth microdilution lead to inconsistent minimal inhibitory concentrations and may be cause for reevaluating testing methods for Klebsiella pneumoniae.

Despite the first-line recommendation of fosfomycin for uncomplicated urinary tract infections (UTIs), there are pressing barriers for optimizing its use for the treatment of non-Escherichia coli Enterobacterales UTI. There are no approved breakpoints for oral use against other Enterobacterales, and the recommended agar dilution (AD) reference method for minimal inhibitory concentration (MIC) determination is largely impractical. Using 160 clinical Klebsiella pneumoniae isolates, we sought to understand rates of skipped wells and MIC imprecision in broth microdilution (BMD) and how that compares to rates of error using AD. Though the Clinical and Laboratory Standards Institute refers to the skipped well phenomena in their recommendation against the use of BMD, there is a paucity of data on its frequency. While AD and BMD produced similar MIC50/90 values (32/256 µg/mL for AD and 64/256 µg/mL for BMD), essential agreement was poor. No-growth wells at concentrations below the MIC occurred in up to 10.9% of wells at a given concentration, as the most frequent scientific error. Growth in concentrations above the measured MIC occurred in up to 3.3% of wells and was seen within three dilutions of the MIC for BMD. Observation of single colonies either at or beyond the measured MIC for AD was also common and occurred up to 8.3% and 2.5% of the time, respectively. The frequent scientific error in both testing methods should prompt re-evaluation of AD guidelines and expansion of MIC testing methods for fosfomycin susceptibility testing, as poor agreement with another method prone to scientific error should not be the main detractor from BMD use.IMPORTANCEDespite the recommendation of fosfomycin for uncomplicated urinary tract infections (UTIs), there are barriers for optimizing its use. There are no approved breakpoints for oral use against other Enterobacterales, and the recommended agar dilution (AD) reference method for MIC determination is largely impractical. The use of broth microdilution (BMD) for fosfomycin testing is not recommended by the Clinical and Laboratory Standards Institute due to unsatisfactory precision and skipped wells-occurrence of no-growth in a single well before the minimal inhibitory concentration (MIC)-and trailing endpoints. We sought to understand rates of skipped wells and growth at concentrations above measured MICs in BMD and how that compares to scientific error using AD. No-growth wells at concentrations below the MIC occurred in up to 10.9% of wells for BMD and single colonies at or beyond measured MICs for AD were also common. Frequent scientific error in both methods should prompt re-evaluation of both AD and BMD for fosfomycin susceptibility testing.

StrawSnake: A Real-Time Strawberry Instance Segmentation Network Based on the Contour Learning Approach

Automated harvesting systems rely heavily on precise and real-time fruit recognition, which is essential for improving efficiency and reducing labor costs. Strawberries, due to their delicate structure and complex growing environments, present unique challenges for automated recognition systems. Current methods predominantly utilize pixel-level and box-based approaches, which are insufficient for real-time applications due to their inability to accurately pinpoint strawberry locations. To address these limitations, this study proposes StrawSnake, a contour-based detection and segmentation network tailored for strawberries. By designing a strawberry-specific octagonal contour and employing deep snake convolution (DSConv) for boundary feature extraction, StrawSnake significantly enhances recognition accuracy and speed. The Multi-scale Feature Reinforcement Block (MFRB) further strengthens the model by focusing on crucial boundary features and aggregating multi-level contour information, which improves global context comprehension. The newly developed TongStraw_DB database and the public StrawDI_Db1 database, consisting of 1080 and 3100 high-resolution strawberry images with manually segmented ground truth contours, respectively, serves as a robust foundation for training and validation. The results indicate that StrawSnake achieves real-time recognition capabilities with high accuracy, outperforming existing methods in various comparative tests. Ablation studies confirm the effectiveness of the DSConv and MFRB modules in boosting performance. StrawSnake’s integration into automated harvesting systems marks a substantial step forward in the field, promising enhanced precision and efficiency in strawberry recognition tasks. This innovation underscores the method’s potential to transform automated harvesting technologies, making them more reliable and effective for practical applications.

Parallel-beams magnetic actuator for in-situ transmission electron microscope observation of mechanical testing

Abstract Understanding the microscopic mechanisms behind mechanical fractures is essential for enhancing material properties and increasing reliability through fatigue suppression. Conventional mechanical testing methods, such as indentation tests that press a sharp needle into a specimen or tensile tests using hydraulic pumps, are unable to capture nanoscale deformations under applied forces. As a result, the microscopic mechanisms that influence mechanical properties are often inferred indirectly, and material design largely depends on the engineer’s intuition and occasional serendipity. To overcome these challenges, in-situ observation techniques utilizing transmission electron microscopes (TEMs) have been developed to enable the observation of sample deformations at the nanoscale. However, despite their high resolution, conventional TEMs are limited by a small available space -often just a few millimeters- that restricts the application of sufficient force to fracture specimens. Traditional actuation methods, such as thermal expansion, electrostatic force, and piezoelectric actuators, fail to generate significant forces within such confined spaces. In response to these limitations, our research involved the development of a micromachine with multiple parallel beams. This device leverages the Laplace force generated by an electric current passing through the beams and the magnetic field of the TEM. We demonstrated the capability to produce significant force using the magnetic field from the microscope’s magnetic lens. The actuator developed in our study successfully generated forces exceeding 50 µN, marking a significant advancement in the in-situ observation capabilities for mechanical testing.

Investigation of the Dewatering Process with Geotextile Tubes by Sedimentation, One- and Two-Dimensional Filtration Test Methods

AbstractDewatering applications are carried out with geotextile tubes for the disposal or reuse of industrial wastes with high water content. Class F Seyitomer thermal power plant fly ash, an industrial waste, was selected in this study. Turbidity, sedimentation and filtration experiments were carried out using anionic and cationic polymers and polypropylene synthetic fiber to investigate the effect of polymers and fibers on the dewatering of fly ash. The use of polymers was determined to significantly accelerate filtration and soil sedimentation speed while leading to a slight increase in the volume of the filter cake. When effective polymer and dosage are used, slurry filtration time can be reduced up to one-eighth of the time and dewatering can be achieved much faster. The addition of synthetic fiber accelerated the sedimentation of the slurry and increased the filtration in the vertical direction, while it did not show a significant effect on the total filtration in two-dimensional filtration. In geotextile tube applications, although one-dimensional filtration experiments might give misleading results in terms of estimating the effectiveness of the polymers used in solid–liquid separation and dewatering times, the jar test, sedimentation and two-dimensional filtration experiments were determined to give compatible and more realistic results. In two-dimensional filtration experiments, approximately 75% of the filtration occurred in the radial direction and the dewatering time was approximately 21–55% of the time estimated by one-dimensional filtration experiment. Geotextile tube dewatering design can be made more predictable and cost-effective in the field by performing small-scale laboratory experiments with the two-dimensional filtration test system designed for this study and various dewatering applications.

Reviewing the progress of corrosion fatigue research on marine structures

This paper reviews the state-of-the-art progress of research into corrosion fatigue on marine structures, both theoretical and experimental. This includes corrosion fatigue life prediction models/methods, load–environment interaction/coupling test methods, accelerated corrosion methods in corrosion fatigue testing, fatigue crack measurement, and corrosion fatigue life assessment in the whole life period. To date, some theoretical models and methods for predicting the corrosion fatigue life of metallic materials or structures have been proposed and applied. Meanwhile, load–environment interaction/coupling testing on metallic material specimens has been maturely developed and widely applied. Some newly developed corrosion fatigue theoretical and experimental methods, based on data-driven machine learning and at-sea monitoring, have received preliminary application. This review of accelerated corrosion methods, fatigue crack measurement methods, and corrosion fatigue life assessment for marine structures in the whole-life period has been undertaken by extensive reference to relevant studies conducted worldwide. Challenges and recommendations for further developing and improving corrosion fatigue assessment methods and test techniques are also reported and discussed.