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Stress measurement plays a crucial role in geomechanics and rock engineering, especially for the design and construction of large-scale rock projects. This paper presents a novel method, based on the traditional stress relief approach, for indirectly measuring rock stress using optical techniques. The proposed method allows for the acquisition of full-field strain evolution on the borehole's inner wall before and after disturbance, facilitating the determination of three-dimensional (3D) stress information at multiple points within a single borehole. The study focuses on presenting the method's theoretical framework, laboratory validation results, and equipment design conception. The theoretical framework comprises three key components: the optical imaging method of the borehole wall, the digital image correlation (DIC) method, and the stress calculation procedure. Laboratory validation tests investigate strain field distribution on the borehole wall under varying stress conditions, with stress results derived from DIC strain data. Remarkably, the optical method demonstrates better measurement accuracy during the unloading stage compared to conventional strain gauge methods. At relatively high stress levels, the optical method demonstrates a relative error of less than 7% and an absolute error within 0.5 MPa. Furthermore, a comparative analysis between the optical method and the conventional contact resistance strain gauge method highlights the optical method's enhanced accuracy and stability, particularly during the unloading stage. The proposed optical stress measurement device represents a pioneering effort in the application of DIC technology to rock engineering, highlighting its potential to advance stress measurement techniques in the field.

Optical monitoring technologies can be used to monitor membrane fouling in real-time and online with the in-situ, fast and nondestructive advantages, which are of great significance for the in-depth understanding of membrane fouling and the optimization of fouling control strategies. In this paper, several kinds of optical real-time monitoring technologies for membrane fouling that had been studied and developed rapidly in recent years were reviewed, including microscopic imaging techniques such as direct observation through membrane, optical coherence tomography and laser confocal microscopy, molecular spectroscopies such as excitation-emission matrix and Raman spectroscopy, and particle image velocimetry. The principles, the typical applications in fouling characterization of these techniques and the derivative techniques were described comprehensively, and the advantages and disadvantages of each technique were analyzed from the aspects of monitoring area and foulant information provided. Finally, the future development direction of the optical monitoring technologies was put forward, which would promote the application of these technologies in the membrane water treatment industries.

As the Internet of Things (IoT) progresses, federated learning (FL), a decentralized machine learning framework that preserves every participant's data privacy, has grown in prominence. However the IoT data possessed by corporations and enterprises frequently has different distributed properties (Non-IID), which has a negative influence on their federated learning. Throughout the local training stage, this issue makes client forget about global information, which therefore slows convergence in general and reduce accuracy. The suggested technique called FedARD, which depends on relationship-based insight distillation, to improve the mining of higher grade global knowledge through local algorithms from a superior dimensions viewpoint over their term of local training in order to maintain global knowledge and prevent forgetting. In order for students to further efficiently acquire global knowledge, it also established an entropy-wise adaptive weights module to control the proportional of loss in single sample knowledge distillation against relational knowledge distillation. FedARD performed stronger than other sophisticated FL approaches in terms of convergence speed along with classification accuracy, as determined by a set of studies on CIFAR10 as well as CIFAR100. [ABSTRACT FROM AUTHOR]

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Medical applications of optical technology have increased tremendously in recent decades. Label-free techniques have the unique advantage of investigating biological samples in vivo without introducing exogenous agents. This is especially beneficial for a rapid clinical translation as it reduces the need for toxicity studies and regulatory approval for exogenous labels. Emerging applications have utilized label-free optical technology for screening, diagnosis, and surgical guidance. Advancements in detection technology and rapid improvements in artificial intelligence have expedited the clinical implementation of some optical technologies. Among numerous biomedical application areas, middle-ear disease is a unique space where label-free technology has great potential. The middle ear has a unique anatomical location that can be accessed through a dark channel, the external auditory canal; it can be sampled through a tympanic membrane of approximately 100 microns in thickness. The tympanic membrane is the only membrane in the body that is surrounded by air on both sides, under normal conditions. Despite these favorable characteristics, current examination modalities for middle-ear space utilize century-old technology such as white-light otoscopy. This paper reviews existing label-free imaging technologies and their current progress in visualizing middle-ear diseases. We discuss potential opportunities, barriers, and practical considerations when transitioning label-free technology to clinical applications. [ABSTRACT FROM AUTHOR]

The proliferation of Mobile Ad hoc Networks (MANETs), where nodes connect with one another to offer the required real-time entertainment services, is where academics are focusing more attention as a result of recent breakthroughs in wireless communication. Decentralised design and wireless connection of MANETs, however, make building safe routing a difficult problem. Artificial Intelligence (AI) and optical technologies have attracted a lot of attention as a way to address these security issues and improve network performance. This study uses a machine learning model to provide a unique security management and routing management method for MANETs. Here, trust-based multi-tier honey pot analysis with stacked reinforcement learning (MHSRL) is used to monitor the security of the network. The linear gradient Distance Vector dynamic Mamdani routing system (LGDVDMR) is used to regulate network routing. For different security-based datasets, experimental analysis is done in terms of throughput, end-end latency, packet delivery ratio, and trust analysis. Generated graph executes both the performance graph and the packet drop. The results of research studies indicate that our method locates the closest node that is the safest and finds problematic nodes with a tolerable load. Proposed technique attained throughput 96%, trust analysis 98%, end-end delay of 59%, packet delivery ratio of 79%. [ABSTRACT FROM AUTHOR]

Singularity phenomena are rare events that occur only with a probability of one in tens of thousands and yet play an important role in the fate of the entire system. Recently, an ultra-wide-field microscopy imaging systems, AMATERAS, have been developed to reliably capture singularity phenomena. However, to determine whether a rare phenomenon captured by microscopy is a true singularity phenomenon—one with a significant impact on the entire system—, causal analysis is required. In this section, we introduce the CALI method, which uses light to inactivate molecules as one of the techniques enabling causal analysis. In addition, we discuss the technical innovations of the CALI method that are required to contribute to the future development of singularity biology.

The formation and decomposition process of natural gas hydrate (NGH) involves many disciplines and theories. Comprehensively evaluating the mechanical and physical properties of hydrate-bearing sediments (HBS) and clarifying the influence law of hydrate decomposition on reservoir structure. It is of great significance to realize the safe exploitation of NGH. At present, the test research on HBS shows the characteristics of diversification, multi-scale and multi-discipline. In order to enhance the comparison of test conclusions and promote the correlation of science and technology. In this study, based on different experimental test methods, the existing test methods are categorized into two types: direct test methods and indirect test methods. By summarizing and analyzing the triaxial test and direct shear test of hydrates, the commonalities and differences of different types of hydrates are pointed out. Meanwhile, the mechanical behavior of hydrate under different influencing factors is reviewed in particular to guide practical works. Then, by combing the visualization techniques of hydrate laboratory tests. The applications of X-ray computed tomography (X-CT) and nuclear magnetic resonance (NMR) in microstructure, pore space, and morphology observation are emphasized. Additionally, an overview of the acoustic and electrical characterization of hydrates in geophysical methods is presented. The correlation of acoustic wave detection and resistivity test with hydrate distribution morphology and saturation estimation is discussed. Finally, the problems existing in the current HBS experimental research are analyzed and targeted suggestions are given. The future development trend of HBS experimental research is discussed, with a view to providing ideas and references for HBS experimental research. • Mechanical and physical properties of HBS are analyzed. • The results of triaxial test and direct shear test on HBS are summarized. • The visualization method of HBS are introduced. • The application of geophysical methods to hydrate research is illustrated. • The current status and challenges of experimental hydrate research are outlined. [ABSTRACT FROM AUTHOR]

The number of layers of 2D materials is of great significance for regulating the performance of nanoelectronic devices and optoelectronic devices, where the optimal thickness of the target sample should be determined before further physical research or device manufacturing steps. At present, a variety of different optical technologies have been proposed to determine the thickness of samples by using the relationship between the number of layers and optical properties, including optical contrast, optical imaging, Raman spectra, photoluminescence spectra, nonlinear spectra, near-field optical imaging, ellipsometry spectra, and hyperspectral imaging. In the past decade, the rapidly growing number of 2D materials and their heterostructures has exceeded the capacity of traditional experimental and computational methods. In recent years, machine learning (ML) is emerging as a powerful tool to support such traditional methods, which brings new opportunities to tap the potential of optical technology in a more perspicacious way. The application of optical technology has greatly facilitated the acquisition of optical information of materials, while ML algorithms provide a fast, high-throughput, and intelligent way to complete back-end data processing and inference. A profound integration of conventional optical technologies and ML algorithms significantly helps 2D materials progress in basic studies and practical applications and further promotes industrial manufacturing. [ABSTRACT FROM AUTHOR]

Wheat quality detection is essential to ensure the safety of wheat circulation and storage. The traditional wheat quality detection methods mainly include artificial sensory evaluation and physicochemical index analysis, which are difficult to meet the requirements for high accuracy and efficiency in modern wheat quality detection due to the disadvantages of subjectivity, destruction of sample integrity and low efficiency. With the rapid development of optical technology, various optical-based methods, using near-infrared spectroscopy technology, hyperspectral imaging technology and terahertz, etc., have been proposed for wheat quality detection. These methods have the characteristics of non-destructiveness and high efficiency which make them popular in wheat quality detection in recent years. In this paper, various state-of-the-art optical-based techniques of wheat quality detection are analyzed and summarized in detail. Firstly, the principle and process of common optical non-destructive detection methods for wheat quality are introduced. Then, the optical techniques used in these detection methods are divided into seven categories, and the comparison of these technologies and their advantages and disadvantages are further discussed. It shows that terahertz technology is regarded as the most promising wheat quality detection method compared with other optical detection technologies, because it can not only detect most types of wheat deterioration, but also has higher accuracy and efficiency. Finally, the research of optical technology in wheat quality detection is prospected. The future research of optical technology-based wheat quality detection mainly includes the construction of wheat quality optical detection standardization database, the fusion of multiple optical detection technologies and multiple quality index information, the improvement of the anti-interference of optical technology and the industrialization of optical inspection technology for wheat quality. These studies are of great significance to improve the detection technology of wheat and ensure the storage safety of wheat in the future.

Hepatic ischemia-reperfusion injury (HIRI) is defined as liver tissue damage and cell death caused by reperfusion during liver transplantation or hepatectomy. Oxidative stress is one of the important mechanisms of HIRI. Studies have shown that the incidence of HIRI is very high, however, the number of patients who can get timely and efficient treatment is small. The reason is not hard to explain that invasive ways of detection and lack of timely of diagnostic methods. Hence, a new detection method is urgently needed in clinic application. Reactive oxygen species (ROS), which are markers of oxidative stress in the liver, could be detected by optical imaging and offer timely and effective non-invasive diagnosis and monitoring. Optical imaging could become the most potential tool of diagnosis of HIRI in the future. In addition, optical technology can also be used in disease treatment. It found that optical therapy has the function of anti-oxidative stress. Consequently, it has possibility to treat HIRI caused by oxidative stress. In this review, we mainly summarized the application and prospect of optical techniques in oxidative stress-induced by HIRI.

Assessment of microcirculation and tissue perfusion parameters is extremely important during surgical interventions, especially during operations on the brain and abdominal organs. Such a system must be handy, non-invasive, and directly integrated into the surgical workflow. To date, there is no standard procedure for assessing blood circulation in routine clinical practice. All the technical proposals are in the stage of research and development. This paper is discussing features of imaging photoplethysmography (IPPG) application to intraoperative visualization and quantitative assessment of tissue perfusion. Measurement of perfusion using photoplethysmography has been known since the 30s of the last century. Nevertheless, discussions of the physiological model underlying this method are still ongoing. An alternative model of light modulation in interaction with blood vessels in vivo was proposed in our group in 2015. Based on this model, we developed a system of intraoperative visualization of blood flow, which uses only video recording of a tissue under study followed by appropriate data processing. Distinguishing feature of the system is synchronous recording of video frames and electrocardiogram. The developed system allows for contactless monitoring of blood flow in cortex and abdominal organs in real time with high spatial resolution. This report is an overview of recent pilot studies on monitoring blood flow parameters during open brain and abdominal surgeries using the IPPG system. It was demonstrated that the quantitative assessment of blood perfusion by IPPG is in good agreement with that obtained by ICG-fluorescence angiography. IPPG can become an objective quantitative monitoring system for tissue perfusion in the operating room due to its simplicity, low cost and no need for any agent injections. [ABSTRACT FROM AUTHOR]

• The optical technology used in the field of viscosity measurement. • The advantages of low sample volumes required and non-contact measurement. • Excellent performance at both macro and micro levels. Viscosity, as a crucial property of liquids, plays a vital role in various fields, including food, chemical, pharmaceutical, personal care, and biomedicine. Therefore, it is of great significance to develop methods that can accurately measure the viscosity of liquids in various environments. To this end, researchers have developed a variety of viscosity measurement techniques. In view of the complexity of viscosity measurement, viscosity measurement in many cases depends on optical technology. Optical-based viscosity measurement technology has demonstrated excellent performance at both macro and micro levels because of its suitability for low sample volumes and the advantages of non-contact measurement. Besides, it can be easily combined with other technologies and is suitable for a wide range of application scenarios. In this paper, we reclassify the optical technology used in the field of viscosity measurement, summarize the latest developments of optical technology in viscosity measurement, and discuss its future development direction. This review aims to assist researchers in mastering the latest developments in optical viscosity measurement techniques and to encourage experts in related fields to utilize and develop these techniques to address specific engineering requirements. [ABSTRACT FROM AUTHOR]

Surgical excision is the golden standard for treatment of intestinal tumors. In this surgical procedure, inadequate perfusion of the anastomosis can lead to postoperative complications, such as anastomotic leakages. Imaging photoplethysmography (iPPG) can potentially provide objective and real-time feedback of the perfusion status of tissues. This feasibility study aims to evaluate an iPPG acquisition system during intestinal surgeries to detect the perfusion levels of the microvasculature tissue bed in different perfusion conditions. This feasibility study assesses three patients that underwent resection of a portion of the small intestine. Data was acquired from fully perfused, non-perfused and anastomosis parts of the intestine during different phases of the surgical procedure. Strategies for limiting motion and noise during acquisition were implemented. iPPG perfusion maps were successfully extracted from the intestine microvasculature, demonstrating that iPPG can be successfully used for detecting perturbations and perfusion changes in intestinal tissues during surgery. This study provides proof of concept for iPPG to detect changes in organ perfusion levels. [ABSTRACT FROM AUTHOR]

Bladder monitoring, including urinary incontinence management and bladder urinary volume monitoring, is a vital part of urological care. Urinary incontinence is a common medical condition affecting the quality of life of more than 420 million people worldwide, and bladder urinary volume is an important indicator to evaluate the function and health of the bladder. Previous studies on non-invasive techniques for urinary incontinence management technology, bladder activity and bladder urine volume monitoring have been conducted. This scoping review outlines the prevalence of bladder monitoring with a focus on recent developments in smart incontinence care wearable devices and the latest technologies for non-invasive bladder urine volume monitoring using ultrasound, optical and electrical bioimpedance techniques. The results found are promising and their application will improve the well-being of the population suffering from neurogenic dysfunction of the bladder and the management of urinary incontinence. The latest research advances in bladder urinary volume monitoring and urinary incontinence management have significantly improved existing market products and solutions and will enable the development of more effective future solutions.

Introduction: The objective of the study was to evaluate the performance of the Abbott Alinity hq advanced multi angle polarized scatter separation (MAPSSTM)‐based optical RBC technology, for the differentiation between iron deficiency anemia (IDA) and β‐thalassemia carrier status. Methods: Four hundred and sixty‐four samples were analyzed. 228 were healthy controls, 30 were β‐thalassemia carriers, and 40 were IDA. Receiver operating characteristics analysis evaluated the performance of red cell parameters and mathematical formulas. Results: RBC concentration was the most efficient discriminant (area under the curve; AUC of 0.963, Youden Index of 0.88) followed by red blood cell distribution width in size distribution (AUC of 0.960 and YI of 0.86), and red blood cell distribution width coefficient of variation (AUC of 0.924, and YI of 0.74). The absolute reticulocyte concentration showed good diagnostic efficiency, with AUC of 0.808. Hemoglobin distribution width, the %CV of directly measured cellular hemoglobin concentration, and CHCr, the average hemoglobin concentration of reticulocytes have emerged as novel discriminating parameters, with AUC of 0.749 and 0.785, respectively. The England and Fraser index was the best discriminating mathematical formula based on Youden Index of 0.91. The Ricerca, red blood cell distribution width index, Green and King, and Mentzner Index formulas also showed strong discriminative power. The Shine and Lal index, together with the recent mathematical formula M/H, (ratio of percent microcytic and hypochromic red blood cells) demonstrated moderate performance with AUC of 0.796 and 0.740, respectively. Conclusion: Extended red cell analysis delivered by the advanced optical technology on the Alinity hq hematology analyzer has efficient diagnostic utility in the initial discrimination of the two most common microcytic anemias: IDA and β‐thalassemia trait. [ABSTRACT FROM AUTHOR]

Biomarkers are the primary indicators of human health. Measurements traditionally rely on targeted binding and assays, which, in turn, rely on specific “labels” that define the biomarker or molecule of interest. While selective and specific, label‐based approaches limit the range of biomarkers a technology can detect. Technologies that can detect and analyze a broad range of biomarkers offer versatility, especially rapid repurposing for new targets. Optical technologies for label‐free biomarker sensing enable noninvasive, minimal‐contact, and wearable or point‐of‐care rapid diagnostic measurements. Herein, label‐free biomarker detection is reviewed with an emphasis on progress toward miniaturized and noninvasive wearable devices. Compact light‐emitting devices and optical detection technologies are presented, tailored for a large range of biomarkers, including recent advances in battery‐free devices. Label‐free detection is reusable, reagent‐free, and allows continuous long‐term monitoring. The potential for optical technologies for label‐free detection in terms of integration, device design, and future applications is summarized.

Surgical excision is the golden standard for treatment of intestinal tumors. In this surgical procedure, inadequate perfusion of the anastomosis can lead to postoperative complications, such as anastomotic leakages. Imaging photoplethysmography (iPPG) can potentially provide objective and real-time feedback of the perfusion status of tissues. This feasibility study aims to evaluate an iPPG acquisition system during intestinal surgeries to detect the perfusion levels of the microvasculature tissue bed in different perfusion conditions. This feasibility study assesses three patients that underwent resection of a portion of the small intestine. Data was acquired from fully perfused, non-perfused and anastomosis parts of the intestine during different phases of the surgical procedure. Strategies for limiting motion and noise during acquisition were implemented. iPPG perfusion maps were successfully extracted from the intestine microvasculature, demonstrating that iPPG can be successfully used for detecting perturbations and perfusion changes in intestinal tissues during surgery. This study provides proof of concept for iPPG to detect changes in organ perfusion levels.

Abstract Background Breast cancer surgeons struggle with differentiating healthy tissue from cancer at the resection margin during surgery. We report on the feasibility of using diffuse reflectance spectroscopy (DRS) for real-time in vivo tissue characterization. Methods Evaluating feasibility of the technology requires a setting in which measurements, imaging and pathology have the best possible correlation. For this purpose an optical biopsy needle was used that had integrated optical fibers at the tip of the needle. This approach enabled the best possible correlation between optical measurement volume and tissue histology. With this optical biopsy needle we acquired real-time DRS data of normal tissue and tumor tissue in 27 patients that underwent an ultrasound guided breast biopsy procedure. Five additional patients were measured in continuous mode in which we obtained DRS measurements along the entire biopsy needle trajectory. We developed and compared three different support vector machine based classification models to classify the DRS measurements. Results With DRS malignant tissue could be discriminated from healthy tissue. The classification model that was based on eight selected wavelengths had the highest accuracy and Matthews Correlation Coefficient (MCC) of 0.93 and 0.87, respectively. In three patients that were measured in continuous mode and had malignant tissue in their biopsy specimen, a clear transition was seen in the classified DRS measurements going from healthy tissue to tumor tissue. This transition was not seen in the other two continuously measured patients that had benign tissue in their biopsy specimen. Conclusions It was concluded that DRS is feasible for integration in a surgical tool that could assist the breast surgeon in detecting positive resection margins during breast surgery. Trail registration NIH US National Library of Medicine–clinicaltrails.gov, NCT01730365. Registered: 10/04/2012 https://clinicaltrials.gov/ct2/show/study/NCT01730365

(1) Background: The modeling, characterization, and mitigation of transient lasers, thermal stress, and thermo-optic effects (TOEs) occurring inside high energy lasers have become hot research topics in laser physics over the past few decades. The physical sources of TOEs are the un-avoidable residual absorption and scattering in the volume and on the surface of passive and active laser elements. Therefore, it is necessary to characterize and mitigate these effects in real laser systems under high-power operations. (2) Methods: The laboratory setup comprised a 10-kW continuous wave laser source with a changeable beam diameter, and dynamic registration of the transient temperature profiles was applied using an infrared camera. Modeling using COMSOL Multiphysics enabled matching of the surface and volume absorption coefficients to the experimental data of the temperature profiles. The beam quality was estimated from the known optical path differences (OPDs) occurring within the examined sample. (3) Results: The absorption loss coefficients of dielectric coatings were determined for the evaluation of several coating technologies. Additionally, OPDs for typical transmissive and reflective elements were determined. (4) Conclusions: The idea of dynamic self-compensation of transient TOEs using a tailored design of the considered transmissive and reflecting elements is proposed.

Abstract The optical fibers which are considered as waveguides can be applied to light transmission applications. The core part of the optical fiber is surrounded by a glass or plastic layer called cladding which is characterized by the refractive index that is lower compared to the core refractive index. The total internal reflection phenomena are necessary for the fine confinements of the light within the waveguide. Basically, optical fibers can be categorized based on the structure, modes number, refractive index profile, dispersion, signal processing ability, and polarization. In this report, we focus on the first three common types of optical fibers. As a common application of the fibers, these can be used in fiber lasers to create and amplify a narrow intense beam of coherent and monochromatic light. Fabrication of optical fiber involves three stages such as the preform formation. Modified chemical vapor deposition (MCVD) method is a known technique, which can be used to fabricate the optical fibers. Optical fiber sensors are well known for wide range applications in optics and photonics. As a sensing application, optical biosensors can be made based on the refractive index changes that used widely for detection of biomolecules in their natural forms. [ABSTRACT FROM AUTHOR]

In the Internet of Things (IoT), a huge number of sensors, actuators and other equipment for data acquisition and processing will be interconnected by means of an omnipresent communication network able to efficiently support heterogeneous transmission technologies and applications. On the one hand, advanced optical communication systems, which already play a significant role in modern networks, are currently evolving to meet very high requirements of modern applications. On the other hand, there are already many ways to utilize optical components and effects for building precise, efficient, and reliable sensors. Thus, optical technologies have the potential to greatly help in realizing future smart infrastructures and systems. This paper gives an overview of currently available and emerging optical technologies for sensing and communication applications and reviews their possible application in the context of the IoT for realizing smart systems and infrastructures.

ITU-T (International Telecommunication Union - Telecommunication Standardization Sector) Study Group (SG) 15 was reorganized for the study period from 2017 to 2020. The new structure of SG15, which includes 3 Working Parties (WPs) and 19 Questions, has been approved. WP chairmen, vicechairmen, and rapporteurs have been appointed. The results of the first SG15 meeting for this study period and the activity plans for the Questions are reported in this article. [ABSTRACT FROM AUTHOR]

In this paper, we report the characterization of the viscosity of biodiesel produced from jatropha curcas . The viscosity measurement has been carried out by using a modified falling ball viscometer as well as optical technology. The viscosity was measured from 28 to 70 °C, which is the interest for determining the quality of biodiesel. We found that the falling ball optical viscometer offers a resolution of a viscosity measurement of ±0.039 mPa s with a relative error of 1.47933%. The measurement process was compared with a commercial viscometer, and it has been demonstrated that the biodiesel produced in Chiapas has good quality. [ABSTRACT FROM AUTHOR]

Inspired by the celebration of the year of light in 2015, this article considers the long lasting interaction among man, vision and light. [ABSTRACT FROM AUTHOR]