Beam Experiments Research Articles

Enhancing Th17 cells drainage through meningeal lymphatic vessels alleviate neuroinflammation after subarachnoid hemorrhage

BackgroundSubarachnoid hemorrhage (SAH) is a severe cerebrovascular disorder primarily caused by the rupture of aneurysm, which results in a high mortality rate and consequently imposes a significant burden on society. The occurrence of SAH initiates an immune response that further exacerbates brain damage. The acute inflammatory reaction subsequent to SAH plays a crucial role in determining the prognosis. Th17 cells, a subset of T cells, are related to the brain injury following SAH, and it is unclear how Th17 cells are cleared in the brain. Meningeal lymphatic vessels are a newly discovered intracranial fluid transport system that has been shown to drain large molecules and immune cells to deep cervical lymph nodes. There is limited understanding of the role of the meningeal lymphatic system in SAH. The objective of this research is to explore the impact and underlying mechanism of drainage Th17 cells by meningeal lymphatics on SAH.MethodsTreatments to manipulate meningeal lymphatic function and the CCR7-CCL21 pathway were administered, including laser ablation, injection of VEGF-C geneknockout, and protein injection. Mouse behavior was assessed using the balance beam experiment and the modified Garcia scoring system. Flow cytometry, enzyme-linked immunosorbent assays (ELISA), and immunofluorescence staining were used to study the impact of meningeal lymphatic on SAH drainage. Select patients with unruptured and ruptured aneurysms in our hospital as the control group and the SAH group, with 7 cases in each group. Peripheral blood and cerebrospinal fluid (CSF) samples were assessed by ELISA and flow cytometry.ResultsMice with SAH showed substantial behavioral abnormalities and brain damage in which immune cells accumulated in the brain. Laser ablation of the meningeal lymphatic system or knockout of the CCR7 gene leads to Th17 cell aggregation in the meninges, resulting in a decreased neurological function score and increased levels of inflammatory factors. Injection of VEGF-C or CCL21 protein promotes Th17 cell drainage to lymph nodes, an increased neurological function score, and decreased levels of inflammatory factors. Clinical blood and CSF results showed that inflammatory factors in SAH group were significantly increased. The number of Th17 cells in the SAH group was significantly higher than the control group. Clinical results confirmed Th17 cells aggravated the level of neuroinflammation after SAH.ConclusionThis study shows that improving the drainage of Th17 cells by meningeal lymphatics via the CCR7-CCL21 pathway can reduce brain damage and improve behavior in the SAH mouse model. This could lead to new treatment options for SAH.

Numerical Modeling of Distributed Macro-Synthetic Fiber and Deformed Bar Reinforcement to Resist Shear

Macro-synthetic fibers are increasingly used in concrete as secondary reinforcement to control temperature and shrinkage cracks, improving durability by limiting crack widths. However, their impact on the shear strength of structural elements remains underexplored, particularly when used in combination with traditional steel reinforcement. To address this knowledge gap, this study developed and calibrated a non-linear numerical model to simulate the shear response of macro-synthetic fiber-reinforced concrete (PFRC) elements, using finite element software VecTor2. The model was calibrated with experimental data from PFRC panels subjected to pure shear loading, incorporating a custom concrete tension-softening model to capture the contribution of fibers. Validation against a broad range of PFRC beam experiments from the literature demonstrated the model’s accuracy, achieving an average predicted-to-experimental shear strength ratio of 0.99 (COV = 5.5%). Additionally, the model successfully replicated key response characteristics such as deformation patterns, crack propagation, and residual strength. The proposed modeling approach provides valuable insights into the interaction between fiber volume and transverse reinforcement. It also serves as a powerful tool for future numerical studies, addressing the existing data gap on PFRC behavior and exploring the synergistic effects of macro-synthetic fibers and steel reinforcement on shear strength.

Exploring the Behavioral Traits of Male Mutant Crup Mice as an Experimental Neurodegenerative Disease Model

The congenic BALB/c-crup (‘crup’ meaning ‘cruza-pernas’ in Portuguese or cross legs in English), a homozygous recessive mutant mouse derived from N-ethyl-N-nitrosourea mutagenesis, exhibits a unique phenotype characterized by hindlimb crossing when the mouse is suspended by its tail, along with age-related neuromotor issues. The study aimed to identify the genetic mutation causing the BALB/c-crup phenotype and evaluate the behavioral responses of the mice. Open field test, elevated plus maze, and elevated beam experiments were conducted to evaluate general activity, motor function, as well as sensorimotor and autonomic nervous systems. Genetic mapping and exome analysis identified a nonsynonymous (missense mutation), a single nucleotide variant, in the Taf15 gene. This mutation results in the p.G55S substitution, where glycine is replaced by serine at position 55 in the gene product. Longitudinal assessment by the open field test revealed altered locomotion, decreased mobility, and reduced rearing and grooming frequency in mutant mice. Sensorimotor function declines were observed through reduced surface righting reflex scores, grip strength, and increased hindquarter angle. In the elevated beam test, mutants exhibited tail hypotonia and aversion to traversing the beam. The elevated plus maze revealed altered behavior in closed arms, suggesting increased anxiety-like behavior or sensorimotor impairment. Our findings provide insights into neurologic and behavioral anomalies associated with a Taf15 gene mutation. The altered locomotion, sensory impairments, and disorientation observed in the crup phenotype indicate a progressive neuromotor condition, potentially serving as a novel mouse model for neurodegenerative diseases.

What does it take to stabilize a naphthalene anion?

We investigate attachment of slow electrons (0-10eV) to naphthalene (Np) clusters in a crossed beam experiment. Supersonic expansions under different conditions using different buffer gases generate the clusters: in He, Ne, and low pressure Ar, neat (Np)N clusters are formed, while we also observe mixed clusters of naphthalene with rare-gas atoms in co-expansion with Ar above 0.5bar and with Kr. Negatively charged (Np)n- and Rgm(Np)n- (Rg = Ar, Kr) clusters are analyzed by mass spectrometry, and electron energy dependent ion yields are measured. We show that the smallest stable naphthalene complex with an excess electron, the dimer (Np)2- anion, cannot be formed in a binary collision of a free electron with (Np)2 dimer, nor with (Np)3 trimer. Evaporation of a weakly bound Ar atom(s) from a mixed ArM(Np)2 cluster following electron attachment leads to the dimer (Np)2- anion. Larger (Np)n-, n > 3, transient cluster anions decay via evaporation of an Np unit on a timescale of tens of microseconds. The self-scavenging process opens around 6eV, where a naphthalene unit is electronically excited by the incoming electron, which is slowed down and trapped. However, the transient negative ion is efficiently stabilized only in the mixed clusters, from which Ar atom(s) can be evaporated.

A Euler-lagrange Model of dynamic internal friction

A Euler-Lagrange model of dynamic internal friction is proposed and is shown to match the frequency and decay of oscillations in both simple extension (pull) and cantilever beam experiments. The proposed dynamic internal frictional stress, τij, is proportional to the rate of change of the engineering stress, σ˙ij. i.e.τij=μmσ˙ij,with μm the dynamic internal friction coefficient. A single value of the dynamic internal friction coefficient is shown to match the results of the experiments for a number of different geometries of the silicon rubber, Dragon SkinTM. Dragon SkinTM is used in skin effects for movies and in prosthetics and cushioning applications. It is chosen here because of its ease of preparation and relatively simple non-linear stress-strain response. Because of these characteristics, it provides a simple starting place for simulating more complicated synthetic rubber and biological materials, which are used in a myriad of commercial applications.

Sputtering of targets in high-intensity heavy-ion beam experiments

Based on available models and experimental data, the sputtering of target atoms in long-term experiments with intense heavy ion (HI) beams has been considered. The experiments on the synthesis of superheavy nuclei (SHN), which are carried out in laboratories around the world, are examples of such experiments encountering the target atoms sputtering in specific conditions. Rotating wheels with a relatively large target annulus area are used in these experiments to reduce the temperature and radiation loads on the target. Large areas of rotating targets allow one to reduce the sputtering yields of target atoms significantly. The question arises about the reliability of these yields in experiments on the synthesis of SHN with Z>118. These nuclei can be produced with extremely low cross sections, requiring HI beam doses exceeding 10 20 particles passed through the target to observe several decay events of the thus synthesized SHN. Estimates based on approximations and simulations considered in this work are presented and compared with some data on actinide target sputtering obtained in experiments performed on the synthesis of SHN.

Medium and short-term effective prestress losses considering multiple factors: Laboratory and on-site beam experiments

The coupling between the creep and shrinkage of concrete, tendon relaxation, and temperature variations makes it difficult to determine the influence of each individual factor on prestress loss. This study investigates the influence of these multiple factors on the medium and short-term prestress of beam bridges, crucial for their durability and safety. Initially, laboratory experiments were conducted on six model beams to analyze medium and short-term prestress variations. Using a pre-designed scheme, the study isolated and quantified the impacts on effective prestress, with losses calculated through superposition. The findings were compared with existing models, leading to the proposal of a refined model for multiple factors affecting prestress. Then the prestress loss experiments on ten full-sized beams, with thirty-five strands, were calibrated based on the proposed model by regression analysis. Based on the modified model of prestress loss, the mentioned influencing factors would be calculated separately, which agree with the measured data from laboratory and in-situ experiments. In the end, the study concludes that creep has the greatest impact on prestress loss, with other factors contributing to varying degrees. Through full-scale tests, parameters for the prestress loss model were verified. The proposed model in this study effectively describes prestress loss within the tested timeframe. The study further concludes that there existed a time lag in prestress tendons and ambient temperature in both laboratory model beams and in-situ full-scale beams. For practical applications in lift-off tests of effective prestress, the appropriate testing time after tensioning to yield relatively stable results is recommended.

Selective Oxidation of Methanol to Methyl Formate on Gold: The Role of Low-Coordinated Sites Revealed by Isothermal Pulsed Molecular Beam Experiments and AIMD Simulations.

To elucidate the role of low-coordinated sites in the partial methanol oxidation to methyl formate (MeFo), the isothermal reactivity of flat Au(111) and stepped Au(332) in pulsed molecular beam experiments was compared for a broad range of reaction conditions. Low-coordinated step sites were found to enhance MeFo selectivity, especially at low coverage conditions, as found at higher temperatures. The analysis of the transient kinetics provides evidence for the essential role of Au x O y phases for MeFo formation and the complex interplay of different oxygen species for the observed selectivity. Ab initio molecular dynamic simulations yielded microscopic insights in the formation of Au x O y phases on flat and stepped gold surfaces emphasizing the role of low-coordinated sites in their formation. Moreover, associated surface restructuring provides atomic-scale insights which align with the experimentally observed transient kinetics in MeFo formation.

A combination of improved spline-kernelled chirplet transform and multi-synchrosqueezing technique for analyzing nonstationary signals and structural instantaneous frequency identification

To improve the accuracy of structural instantaneous frequency (IF) identified by the spline-kernelled chirplet transform, a combination of an improved spline-kernelled chirplet transform and a multi-synchrosqueezing technique is proposed for analyzing nonstationary signals and structural IF identification in this paper. Firstly, an improved spline-kernelled chirplet transform (ISCT) is put forward by introducing a three parameter Gaussian window function for an existing spline-kernelled chirplet transform. These three parameters are successfully obtained through an optimization algorithm and the energy concentration measure (CM). Then, combined with a multi-synchrosqueezing technique, a so-called improved multi-synchrosqueezing spline-kernelled chirplet transform (IMSSSCT) approach is further presented to improve the time–frequency energy concentration. Finally, the accuracy and practicability of the proposed IMSSSCT method are validated by analytical signals, a single-degree-of-freedom Duffing system, a three-layer shear frame, as well as a cantilever beam experiment. The research results indicate that the IMSSSCT technique can effectively and accurately identify the IFs of nonlinear and time-varying structures.

Thermal modeling of variable process parameter effects in powder bed fusion using electron beam

Purpose This study aims to develop a novel thermal modeling strategy to simulate electron beam powder bed fusion at part scale with machine-varying process parameters strategy. Single-bead and part-scale experiments and modeling were studied. Scanning strategies were described by the process controlling functions that enabled modeling. Design/methodology/approach The finite element analysis thermal model was used along with the powder bed fusion with electron beam experiments. The proposed strategy involves dividing a part into smaller sections and creating meso-scale models for each subsection. These meso-scale models take into consideration the variable process parameters, including power and velocity of the moving heat source, during part building. Subsequently, these models are integrated to perform partscale simulations, enabling more realistic predictions of thermal accumulation and resulting distortions. The model was built and validated with single-bead experiments and bulky parts with different features. Findings Single-bead experiments demonstrated an average error rate of 6%–24% for melt pool dimension prediction using the proposed meso-scale models with different scanning control functions. Part-scale simulations for three different geometries (cantilever beams with supports, bulk artifact and topology-optimized transfer arm) showed good agreement between modeled temperature changes and experimental deformation values. Originality/value This study presents a novel approach for electron beam powder bed fusion modeling that leverages meso-scale models to capture the influence of variable process parameters on part quality. This strategy offers improved accuracy for predicting part geometry and identifying potential defects, leading to a more efficient additive manufacturing process.

Low-Energy Electron Interactions with Methyl-p-benzoquinone: A Study of Negative Ion Formation.

Methyl-p-benzoquinone (MpBQ, CH3C6H3(=O)2) is a prototypical molecule in the study of quinones, which are compounds of relevance in biology and several redox reactions. Understanding the electron attachment properties of MpBQ and its ability to form anions is crucial in elucidating its role in these reactions. In this study, we investigate electron attachment to MpBQ employing a crossed electron-molecular beam experiment in the electron energy range of approximately 0 to 12 eV, as well as theoretical approaches using quantum chemical and electron scattering calculations. Six anionic species were identified: C7H6O2 -, C7H5O2 -, C6H5O-, C4HO-, C2H2 -, and O-. The parent anion is formed most efficiently, with large cross sections, through two resonances at electron energies between 1 and 2 eV. Potential reaction pathways for all negative ions observed are explored, and the experimental appearance energies are compared with calculated thermochemical thresholds. Although exhibiting similar electron attachment properties to pBQ, MpBQ's additional methyl group introduces entirely new dissociative reactions, while quenching others, underscoring its distinctive chemical behavior.

Unveiling the Reaction Mechanism of the N(2D) + Pyridine Reaction: Ring-Contraction versus 7-Membered-Ring Formation Channels.

Despite the relevance of the reactions of the prototypical nitrogen-containing six-membered aromatic molecule (N-heterocyclic) of pyridine (C6H5N) in environmental science, astrochemistry, planetary science, prebiotic chemistry, and materials science, few experimental/theoretical studies exist on the bimolecular reactions involving pyridine and neutral atomic/molecular radicals. We report a combined experimental and theoretical study on the elementary reaction of pyridine with excited nitrogen atoms, N(2D), aimed at providing information about the primary reaction products and their branching fractions (BFs). From previous crossed molecular beam (CMB) experiments with mass-spectrometric detection and present synergistic calculations of the reactive potential energy surface (PES) and product BFs we have unveiled the reaction mechanism. It is found that the reaction proceeds via N(2D) barrierless addition to pyridine that, via bridged intermediates followed by N atom "sliding" into the ring, leads to 7-membered-ring structures. They further evolve, mainly via ring-contraction mechanisms toward 5-membered-ring radical products and, to a smaller extent, via H-displacement mechanisms toward 7-membered-ring isomeric products and their isomers. Using the theoretical statistical estimates, an improved fit of the experimental data previously reported has been obtained, leading to the following results for the dominant product channels: C4H4N (pyrrolyl) + HCN (BF = 0.61 ± 0.20), C3H3N2 (1H-imidazolyl/1H-pyrazolyl) + C2H2 (BF = 0.11 ± 0.06), and C5H4N2 (7-membered-ring molecules or pyrrole carbonitriles) + H (BF = 0.28 ± 0.10). The ring-contraction product channels C4H4N (pyrrolyl) + HCN, C3H3N2 (1H-imidazolyl) + C2H2, C3H3N2 (1H-pyrazolyl) + C2H2, and C5H5 (cyclopentadienyl) + N2 have statistical BFs of 0.54, 0.09, 0.11, and 0.07, respectively. Among the H-displacement channels, the cyclic-CHCHCHCHNCN + H channel and cyclic-CHCHCHCHCN2 + H are theoretically predicted to have a comparable BF (0.07 and 0.06, respectively), while the other isomeric 7-membered-ring molecule + H channel has a BF of 0.03. Pyrrole-carbonitriles and 1H-ethynyl-1H-imidazole (+ H) isomeric channels have an overall BF of 0.03. Implications for the chemistry of Saturn's moon Titan and prebiotic chemistry, as well as for understanding the N-doping of graphene or carbon nanotubes, are noted.

A stiffness prediction method for variable cross‐section CFRP laminated beam

AbstractTo efficiently design the stiffness of the laminated composite blade‐like structure, an analytical method to assess deformation of variable cross‐section laminated beam under cantilever bending load was developed, in which a local ply density matrix method was introduced to characterize the ply‐up in arbitrary cross‐section after ply drop‐off process and infinitesimal element segment method was used to convert complex variable cross‐section specimen into local equal cross‐section beam structure. The model was validated by the cantilever beam experiment with relative predicted error of stiffness of 5.7%. Inner and outer ply drop‐off models were analyzed using the proposed analytical method. The results show that: (1) stiffness of the outer ply drop‐off model is the highest, at 13.07 N/mm, while that of the inner ply drop‐off model 2 is the lowest, about 17.8% lower than the outer ply drop‐off model; (2) maximum relative deformation difference between the inner ply drop‐off model 2 and outer ply drop‐off model is 21.7% at the free side of the cantilever beam. It indicates that anti‐deformation ability of the variable cross‐section laminated structure can be efficiently designed by the proposed analytical method, especially for the section close to the free side.Highlights Developed a bending stiffness prediction method for composite beam. Variable cross‐section feature of the composite laminate was considered. Local ply density matrix method was introduced to characterize ply drop‐off. Proposed method was validated by cantilever beam bending experiment. Inner and outer ply drop‐off models were compared by the proposed method.

Reliability of Cross Sections of the Photoneutron Reactions on 51V and 59Co Nuclei in the Bremsstrahlung Beam Experiments

Reliability of Cross Sections of the Photoneutron Reactions on 51V and 59Co Nuclei in the Bremsstrahlung Beam Experiments

The role of intersystem crossing in the reactive collision of S+(4S) with H2.

We report a study on the reactive collision of S+(4S) with H2, HD, and D2 combining guided ion beam experiments and quantum-mechanical calculations. It is found that the reactive cross sections reflect the existence of two different mechanisms, one being spin-forbidden. Using different models, we demonstrate that the spin-forbidden pathway follows a complex mechanism involving three electronic states instead of two as previously thought. The good agreement between theory and experiment validates the methodology employed and allows us to fully understand the reaction mechanism. This study also provides new fundamental insights into the intersystem crossing process.

Limit analysis and design recommendations for fiber‐reinforced concrete subjected to shear

AbstractIt is widely recognized in both research and practice that fibers have great potential to partially, or completely, substitute conventional transverse reinforcement in webs of girders subjected to moderate shear forces. However, despite extensive research in recent years, there is still no consensus in the research community on the mechanically sound modeling of the shear strength of fiber‐reinforced concrete (FRC). Accordingly, current code provisions for the design of FRC to resist shear rely on (semi‐)empirical approaches and are thus justifiably restrictive. This article addresses this knowledge gap by proposing the application of the theory of plasticity to the design of FRC webs. Limit analysis methods for conventionally reinforced concrete are extended to FRC by incorporating the residual crack‐bridging stress offered by the fibers in a consistent manner. This stress, as well as the limits of applicability of the theory of plasticity, are derived through a sensitivity analysis using the recently developed Cracked Membrane Model for FRC considering fixed, interlocking cracks. Based on these investigations, a straightforward and efficient mechanically based shear design model suitable for the design of FRC webs with and without conventional transverse bar reinforcement is proposed. The model is validated against a large database of panel and beam experiments, providing valuable insights into its reliability.

Mechanical Properties, Workability, and Experiments of Reinforced Composite Beams with Alternative Binder and Aggregate

Arguably the most important element in the sustainability of concrete development is the discovery of an optimal sustainable binder and substitution for the increasingly depleted reserves of natural aggregates. Considerable interest has been shown in alkali-activated materials, which possess good characteristics and could be considered environmentally friendly because of their use of secondary materials in production. The aim of this study was the determination of the mechanical properties of three different mixtures based on the same locally accessible raw materials. The reference mixture contained Portland cement, the second mix contained a finely ground granulated blast furnace slag instead of cement, and the third mixture contained a portion of light artificial aggregate. The experiments focused on the testing and mutual comparison of the processability of the fresh mixture and mechanical characteristics (like compressive and flexural strength, as well as resistance to high temperatures and surface layer tear strength tests). Reinforced concrete beams without shear reinforcement and with three levels of reinforcement were also tested with a three-point bend test. The results show that, overall, the mechanical properties of all the tested mixtures were similar, but each had its own disadvantages. For example, the blast furnace slag-based mixture had a more vulnerable surface layer or a debatable loss of bulk density in the light aggregate mix at the expense of the mechanical properties. One of the main results of the research is that it was possible to technologically produce beams from the alkali-activated concrete (AAC) mixture. Then, the performed beam experiments verified the mechanism of damage, collapse, and load capacity. The obtained results are essential because they present the use of AAC not only in laboratory conditions but also for building elements. In beams without shear reinforcement, the typical tensile cracks caused by bending and shear cracks appeared under loading, where their character was affected depending on the degree of beam reinforcement and loading.

New results on the two-body decay of neutrons shed new light on neutron stars

In attempts to resolve the neutron lifetime puzzle, there was suggested a hypothetical decay of neutrons into some unspecified dark matter (DM) particles. Later there were performed studies on how the hypothetical decay of neutrons would affect neutron stars. Recently it was shown that with the allowance for the second solution of Dirac equation for hydrogen atoms, the theoretical branching ratio (BR) for the two-body decay of neutrons (compared to their three-body decay) is amplified by a factor of 3300 from 0.000004. So, the BR becomes about 1.3% in the excellent agreement with the “experimental” BR = (1.15 ± 0.27)% required for reconciling the two distinct experimental values of the neutron lifetime: one from the beam experiments, another from the trap experiments. This meant that the two-body decay of neutrons in the beam experiments (that count only the protons) plays a much more sizable part in the overestimation of the lifetime of neutrons in these experiments than previously thought. Hydrogen atoms corresponding to the second solution of Dirac equations are called the second flavor of hydrogen atoms (SFHA) by the analogy with the flavors of quarks. The existence of the SFHA is evidenced by four different types of atomic/molecular experiments. The primary feature of the SFHA is that due to having only the s-states, they do not emit or absorb the electromagnetic radiation (except for the 21 cm line): they are practically dark. The SFHA became a candidate for a part of DM for the first time after the SFHA-based successful qualitative and quantitative explanation of the perplexing observation by Bowman et al. of the anomalous absorption in the redshifted 21 cm line from the early Universe. In the present paper we analyzed how this neutron decay into the SFHA affects neutron stars. We showed that old neutron stars could very slowly generate the new specific, described in detail baryonic DM in the form of the SFHA. Some old neutron stars would release it into their tiny atmospheres, while some other old neutron stars would release it into the interstellar medium. Besides, mergers of a neutron star with another neutron star or with a black hole, accompanied by the ejection of neutron-rich material, can also lead to the formation of SFHA as the ejecta cools down. This is another interesting aspect of the multi-messenger astronomy focused on studying these mergers through the gravitational waves they generate. These mechanisms of generating new baryonic DM in the universe should have the fundamental importance. We point out the indirect observational evidence of the continuing generation of new baryonic DM. We hope that our results will stimulate a further research in this direction.

Temperature-based damage detection for the commissioning dataset of the MX3D Bridge

Environmental and operational variations (EOV) remain a major obstacle for the successful transfer of structural health monitoring (SHM) techniques from laboratory experiments, such as cracked beam experiments, to full-scale structures, such as long-span bridges. With evidence that timely interventions significantly increase the service-life and reduce the overall life-cycle cost of ageing infrastructure, carrying out SHM in the presence of EOV, such as temperature, is therefore of high priority within the civil engineering community. The temperature-based measurement-interpretation (TB-MI) approach was developed to monitor the thermal response of an instrumented structure and detect changes linked to damage by minimising the impact that temperature variations have on anomaly detection techniques. The iterative regression-based thermal response prediction (IRBTRP) methodology is utilised in the TB-MI approach, and is trained on the healthy condition of the bridge to predict its undamaged response to temperature fluctuations. Thermal response predictions are compared to the measured response and deviations between them are indicative of a variation in the thermal response, due to structural change such as damage. Small deviations can then be identified using anomaly detection techniques, which results in earlier damage detection than if thermal response predictions had not been used. The TB-MI approach and the IRBTRP methodology have been applied to detect damage on the MX3D Bridge, the world’s first structure produced through metal additive manufacturing (i.e. 3D printing). This study demonstrates that the use of the TB-MI approach enables earlier and more widespread damage detection amongst multiple sensor groups, compared to when no temperature effects are considered. The adoption of the TB-MI approach can therefore greatly increase the reliability of and our reliance on SHM techniques for critical infrastructure.

Experimental Study of the Flexural Performance of GFRP-Reinforced Seawater Sea Sand Concrete Beams with Built-In GFRP Tubes.

The use of seawater sea sand concrete (SSSC) and fiber-reinforced polymer (FRP) has broad application prospect in island and coastal areas. However, the elastic modulus of FRP reinforcement is obviously lower than that of ordinary steel reinforcement, and the properties of SSSC are different from that of ordinary concrete, which results in a limit in the bearing capacity and stiffness of structures. In order to improve the flexural performance of FRP-reinforced SSSC beams, a novel SSSC beam with built-in glass FRP (GFRP) tubes was proposed in this study. Referring to many large-scale beam experiments, one specimen was used for one situation to illustrate the study considering costs and feasibility. Firstly, flexural performance tests of SSSC beams with GFRP tubes were conducted. Then, the effects of the GFRP tubes' height, the strength grades of concrete inside and outside the GFRP tubes, and the GFRP reinforcement ratio on the flexural behaviors of the beams were investigated. In addition, the concept of capacity reserve was proposed to assess the ductility of the beams, and the interaction between the concrete outside the GFRP tube, the GFRP tube and concrete inside the tube was discussed. Finally, the formulas for the normal section bearing capacity of beams with built-in GFRP tubes were derived and verified. Compared to the beam without GFRP tubes, under the same conditions, the ultimate bearing capacities of the SSSC beam with 80 mm, 100, and 200 mm height GFRP tubes were increased by 17.67 kN, 24.52 kN, and 144.42 kN, respectively.