Limited Depth Research Articles

Sampling Error Analysis in Quantum Krylov Subspace Diagonalization

Quantum Krylov subspace diagonalization (QKSD) is an emerging method used in place of quantum phase estimation in the early fault-tolerant era, where limited quantum circuit depth is available. In contrast to the classical Krylov subspace diagonalization (KSD) or the Lanczos method, QKSD exploits the quantum computer to efficiently estimate the eigenvalues of large-size Hamiltonians through a faster Krylov projection. However, unlike classical KSD, which is solely concerned with machine precision, QKSD is inherently accompanied by errors originating from a finite number of samples. Moreover, due to difficulty establishing an artificial orthogonal basis, ill-conditioning problems are often encountered, rendering the solution vulnerable to noise. In this work, we present a nonasymptotic theoretical framework to assess the relationship between sampling noise and its effects on eigenvalues. We also propose an optimal solution to cope with large condition numbers by eliminating the ill-conditioned bases. Numerical simulations of the one-dimensional Hubbard model demonstrate that the error bound of finite samplings accurately predicts the experimental errors in well-conditioned regions.

Fluid depth-dependent biofilm characteristics and their influence on sulfate-reducing bacteria-induced corrosion of carbon steel

This study investigates the response of biofilm characteristics to variations in fluid depth and their influence on the corrosion behavior of carbon steel (C1020) under low-flow fluid conditions, utilizing Desulfovibrio vulgaris. The experiments were conducted in an anaerobic chamber at 30 °C, utilizing modified Baar's medium as the testing medium. The findings reveal that fluid depth significantly impacts biofilm-corrosion product composite formation, with deeper depths promoting thicker and more heterogeneous biofilm-corrosion product layer compared to shallower depths, where a thinner and more uniform biofilm-corrosion product layer is observed. Moreover, the characteristics of initially attached biofilms was verified as the primary factor affecting subsequent corrosion behavior during prolonged exposure. Corrosion analysis reveals that greater fluid depth leads to increased weight loss (91 ± 13.2 mg/cm2) and deeper pit depths (540 ± 69 μm), surpassing those observed in shallower test media (21 ± 2.3 mg/cm2 and 105 ± 17 μm) after 28 days of exposure. The corrosion products within the biofilm were predominantly FeS and Fe3(PO4)2·8H2O. A direct relationship was observed between the thickness of this biofilm-corrosion product layer and the progression of pit depth, suggesting a strong correlation between carbon steel corrosion and biofilm development in limited fluid depths (e.g., 5–15 mm). Furthermore, a significant association between the deepest pits (average) and the number of sessile cells within the biofilm underscores the pivotal role of sessile cell numbers in carbon steel corrosion.

X-ray triggered scintillator versatile nanocatalytic platform for synergistic photodynamic/chemodynamic therapy

Nanocatalysts with photodynamic therapy (PDT) and chemodynamic therapy (CDT) are excellent for tumor therapy. However, it is still challenging to achieve complete tumor eradication due to the drawbacks of limited penetration depth of intratumoural tissues, hypoxia and complexity of the tumor microenvironment (TME). Herein, we fabricated an integrated multifunctional nanoreactor (LuAG:Tb/Ce-RB@ZIF-8-Au2Pt-HA, LRZAPH) combining scintillating nanoparticles (SCNPs, LuAG:Tb/Ce), a metal-organic framework (ZIF-8), and bimetallic Au2Pt for X-ray-triggered PDT and dual noble-metal nanozyme catalyzed CDT. Such a nanoreactor not only significantly enhanced the PDT effect under X-ray irradiation through full resonance energy transfer from LuAG:Tb/Ce scintillator to Ross Bengal (RB), but also facilitated the reactive oxygen species (ROS) and oxygen (O2) production through the excellent peroxidase-like (POD-like) and catalase-like (CAT-like) catalytic properties of Au2Pt nanozymes. O2 also alleviates hypoxia in intratumoural tissues during coordinated PDT. In addition, the dissociation behavior of ZIF-8 with pH-responsive and targeted of hyaluronic acid (HA) in acidic TME significantly enhanced the therapeutic efficacy of LRZAPH nanocatalysts. Significantly, the high tumor growth inhibition rate of 93 % was revealed due to radiotherapy (RT)/PDT/CDT synergetic therapy in vivo, which minimized the toxic and side effects of conventional clinical radiotherapy/chemotherapy on human. The synergistic effect of LRZAPH nanocatalysts on PDT and catalytically induced CDT is expected to provide new pathways for effective treatment of deep tumors.

REWARE: a seismic processing algorithm to retrieve geological information from the water column

SUMMARY When interpreting marine very high-resolution (VHR) single-channel seismic reflection data, the signal in the water column is generally considered as noise and is often eliminated by a water-mute application to focus on geological information under the seafloor. Alternatively, the signal in the water column can be used to study ocean currents or gas/fluid emissions. To provide images of the sedimentary formations and tectonic structures beneath the seafloor in shallow water regions, such as continental shelves and lakes, marine seismic reflection profiles are often acquired using a single-channel streamer and sparker-type source, providing VHR data, with limited penetration depth. To exploit the full potential of these single-channel data, we propose a simple algorithm, called REWARE (Recovery of Water-column Acoustic Reflectors). This algorithm allows to extract further geological information from the water-column data using open-source codes (Seismic Un*x), adding the coherent signal from the previous shots, recorded in the water column, to the previous traces. The record length becomes longer while maintaining a very high trace-to-trace consistency. To demonstrate its efficiency, we present two examples of the REWARE processing in two different geological contexts: the East Sardinia shelf (Italy) and the North Evia Gulf (Greece). This method provides deeper images than with original data for seismic data acquired across steep slopes, such as canyons or continental shelf breaks. Thus, depending on the seafloor geometry and subseafloor structures, it is possible to image or map sediment layers and tectonic structures at depth, keeping a very high structural resolution.

Distinct cognitive and functional connectivity features from healthy cohorts can identify clinical obsessive-compulsive disorder.

Improving diagnostic accuracy of obsessive-compulsive disorder (OCD) using models of brain imaging data is a key goal of the field, but this objective is challenging due to the limited size and phenotypic depth of clinical datasets. Leveraging the phenotypic diversity in large non-clinical datasets such as the UK Biobank (UKBB), offers a potential solution to this problem. Nevertheless, it remains unclear whether classification models trained on non-clinical populations will generalise to individuals with clinical OCD. This question is also relevant for the conceptualisation of OCD; specifically, whether the symptomology of OCD exists on a continuum from normal to pathological. Here, we examined a recently published "meta-matching" model trained on functional connectivity data from five large normative datasets (N=45,507) to predict cognitive, health and demographic variables. Specifically, we tested whether this model could classify OCD status in three independent clinical datasets (N=345). We found that the model could identify out-of-sample OCD individuals. Notably, the most predictive functional connectivity features mapped onto known cortico-striatal abnormalities in OCD and correlated with genetic brain expression maps previously implicated in the disorder. Further, the meta-matching model relied upon estimates of cognitive functions, such as cognitive flexibility and inhibition, to successfully predict OCD. These findings suggest that variability in non-clinical brain and behavioural features can discriminate clinical OCD status. These results support a dimensional and transdiagnostic conceptualisation of the brain and behavioural basis of OCD, with implications for research approaches and treatment targets.

EVALUATION OF DEFORMATION PARAMETERS OF SILO FOUNDATIONS REINFORCED WITH SOIL-CEMENT ELEMENTS

The mandatory controlled criterion for steel silos is the limitation of foundation settlement and tilting, which is regulated by DBN V.2.6-221:2021. The threshold value of silo settlement is Smax,u = 150 mm. The most economical foundation solution is a large-sized slab on a natural base or a soil cushion. It is possible to stabilise the weak base by reinforcing it with vertical soil-cement elements (SCE). In Ukraine, most foundations have an underground gallery or silo floor. When the silos are first loaded, there is geodetic monitoring of the vertical settlement of the silo base and comparison of its data with the threshold values of settlement and tilting. The objective is to investigate the effect of limited-depth soil reinforcement on the stabilisation of the soil base and the average total foundation settlement. The task of the study is to create a methodology for predicting the impact of reinforcement with soil-cement elements on the parameters of the soil base general stiffness for a silo foundation. The research methods are geodetic monitoring of settlements around the perimeter of silo foundations during initial loading at four different elevators with different geological conditions. Thus, the predicting method of the impact while reinforcing with soil-cement elements on the general stiffness parameters of the soil base for the silo foundation was tested on the bases of silos for four elevators. These elevators represent different engineering and geological conditions. The proof of the methodology’s validity is the coincidence with the results of geodetic subsidence monitoring along the perimeter of silo foundations. According to the research results, it is possible to state that the reinforcement of the foundation base with vertical soil-cement elements allows for the effective stabilisation of soil parameters. We propose an evaluation method of the reinforcement effect with soil-cement elements in the form of the stabilisation coefficient for the soil base, kEi. We further prove the primary role of the soil-cement reinforcing elements operation and their length while stabilising the base. The base stiffness is stabilised at the compressible stratum depth and beyond the foundation boundaries. It is possible to use the method of reinforcement influence evaluation to determine the actual parameters of the stabilised soil base, n, according to geodetic monitoring data. The authors have studied the effect of limited depth reinforcement for stabilising the foundation. The research obtained the empirical dependence of the reinforcement required depth at given depth values for the base compressible layer. The authors proposed using the linearly deformed layer method, considering the operation of soil-cement elements as discrete soil reinforcement. The numerous experiments with the Finite Element Method confirm the high convergence of the calculated results with those obtained analytically. Keywords: foundation settlement, soil-cement element, geodetic monitoring, steel silo, foundation stiffness.

A bifunctional lactoferrin-derived amyloid coating prevents bacterial adhesion and occludes dentinal tubules via deep remineralization

Dentin hypersensitivity (DH) manifests as sharp and uncomfortable pain due to the exposure of dentinal tubules (DTs) following the erosion of tooth enamel. Desensitizing agents commonly used in clinical practice have limitations such as limited depth of penetration, slow remineralization and no antimicrobial properties. To alleviate these challenges, our study designed a lactoferrin-derived amyloid nanofilm (PTLF nanofilm) inspired by the saliva-acquired membrane (SAP). The nanofilm utilises Tris(2-carboxyethyl)phosphine (TCEP) to disrupt the disulfide bonds of lactoferrin (LF) under physiological conditions. The PTLF nanofilm modifies surfaces across various substrates and effectively prevents the early and stable adhesion of cariogenic bacteria, such as Streptococcus mutans and Lactobacillus acidophilus. Simultaneously, it adheres rapidly and securely to demineralized dentin surfaces, facilitating in-situ remineralization of HAP through a simple immersion process. This leads to the formation of a remineralized layer resembling natural dentin, with an occlusion depth of dentinal tubules exceeding 80 µm after three days. The in vivo and vitro results confirm that the PTLF nanofilm possesses good biocompatibility and its ability to exert simultaneous antimicrobial effects and dentin remineralization. Accordingly, this innovative bifunctional PTLF amyloid coating offers promising prospects for the management of DH-related conditions. Statement of significance1.We design a simple, fast, inexpensive, and easy-to-process PTLF nanofilm for nearly any material surface or shape.2.The PTLF nanofilm modifies surfaces across various substrates and effectively prevents the adhesion of cariogenic bacteria, such as Streptococcus mutans and Lactobacillus acidophilus.3.The abundant functional groups on the surface of PTLF nanofilm facilitate bioactive hydroxyapatite (HAP) formation and maintain stability at the HAP remineralization interface.

Dual-Locked Probe with Activatable Sonoafterglow Luminescence for Precise Imaging of MET-Induced Liver Injury.

Metformin (MET) is currently the first-line treatment for type 2 diabetes mellitus (T2DM). However, overdose and long-term use of MET may induce a serious liver injury. What's worse, diagnosis of MET-induced liver injury remains challenging in clinic. Although several probes have been reported for imaging MET-induced liver injury utilizing upregulated hepatic H2S as a biomarker, they are still at risk of nonspecific activation in complex physiological environments and rely on light excitation with limited imaging depth. Herein, we rationally designed and developed a dual-locked probe, DPA-H2S, for precise imaging of MET-induced liver injury by H2S-activated sonoafterglow luminescence. DPA-H2S is a small molecule consisting of a sonosensitizer protoporphyrin IX (PpIX) and an afterglow substrate that is dual-locked with a H2S-responsive 2,4-dinitrobenzene group and a 1O2-responsive electron-rich double bond. When employing DPA-H2S for imaging of MET-induced liver injury in vivo, since the PpIX moiety can produce 1O2 in situ at the liver site under focused ultrasound (US) irradiation, the two locks of DPA-H2S can be specifically activated by the highly upregulated H2S at the liver injury sites and the in situ generated 1O2, respectively. Thus, the sonoafterglow signal of DPA-H2S is significantly turned on, enabling precise imaging of the MET-induced liver injury. In vitro results showed that, through H2S-activated sonoafterglow luminescence, DPA-H2S was capable of imaging H2S with good sensitivity and high selectivity and realized deep tissue imaging (∼20 mm, signal-to-background ratio (SBR) = 3.4). Furthermore, we successfully applied DPA-H2S for precise in vivo imaging of MET-induced liver injury. We anticipate that our dual-locked probe, DPA-H2S, may serve as a promising tool in assisting the diagnosis of MET-induced liver injury in clinics and informing the clinical utilization of MET in the near future.

Self-Chemiluminescence-Triggered Ir(III) Complex Photosensitizer for Photodynamic Therapy against Hypoxic Tumor.

The limited optical penetration depth and hypoxic tumor microenvironment (TME) are key factors that hinder the practical applications of conventional photodynamic therapy (PDT). To fundamentally address these issues, self-luminescent photosensitizers (PSs) can achieve efficient PDT. Herein, a self-chemiluminescence (CL)-triggered Ir complex PS, namely, IrL2, with low-O2-dependence type I photochemical processes is reported for efficient PDT. The rational design achieves efficient chemiluminescence resonance energy transfer (CRET) from covalently bonded luminol units to the Ir complex in IrL2 under the catalysis of H2O2 and hemoglobin (Hb) to generate O2•- and 1O2. Liposome IrL2H nanoparticles (NPs) are constructed by loading IrL2 and Hb. The intracellular H2O2 and loaded Hb catalyze the luminol part of IrL2H, and the Ir2 part is then excited to produce types I and II reactive oxygen species (ROS) through CRET, inducing cell death, even under hypoxic conditions, and promoting cell apoptosis. IrL2H is used for tumor imaging and inhibits tumor growth in 4T1-bearing mouse models through intratumoral injection without external light sources. This work provides new designs for transition metal complex PSs that conquer the limitations of external light sources and the hypoxic TME in PDT.

The use of peritoneum in female genital gender-affirming surgery: A systematic review

Genital gender-affirming surgery (GAS) plays a crucial role in alleviating psychological discomfort and assisting transgender patients in achieving their transition goals. One of the most common procedures for primary genital reconstruction in transwomen is penile inversion vaginoplasty. But it presents a risk of vaginal stenosis and limited depth, particularly in cases with inadequate penile and scrotal tissue. This limitation becomes more relevant as transgender individuals increasingly seek early hormone therapy and puberty blockade. We conducted a literature review focusing on studies published between 2000 and 2022 to explore the application of peritoneal vaginoplasty, a technique primarily used in cisgender women with congenital vaginal agenesis, to address these challenges in transwomen.Data were extracted from 13 selected articles reporting 313 patients who underwent peritoneal vaginoplasty.Peritoneal vaginoplasty was found to offer advantages in terms of neovaginal depth and width, with an average depth of 13.8 cm and width of 3.5 cm. Patient reporting satisfaction rates for sexual intercourse and dilatation achievement were high, with 96.2% and 94.4% respectively. The technique did not result in an increased rate of complications compared to traditional penile inversion vaginoplasty.This review suggests that peritoneal vaginoplasty could be consider first for transwomen genital GAS, especially in cases with limited penile tissue. The well-vascularized peritoneum provides tissue with regenerative capacities and reduces the risk of stenosis. Moreover, peritoneum remains unaffected by hormonal treatments and allows deep enough neovaginal canals. This method is safe and does not lead to increased complications compared to traditional techniques.

Kinetic simulation of uranium migration in granite fissure media of beishan, gansu, China: A case study based on the Laplace transform and inverse transform methods

Deep geological disposal is currently considered the most practical and feasible method for disposing high-level radioactive wastes (HLWs). One of its key scientific issues is the migration of nuclides in fissure media. However, studies on the migration of nuclides like U-238 are relatively limited. In this study, the granite rock masses in Beishan, Gansu were selected to construct a physical and mathematical model of U-238 migration using the Laplace transform and inverse transform methods. Based on the numerical methods, the kinetic migration of nuclide U-238 in the fissure media of granite was simulated, and the effects of parameters such as fissure width, hydraulic gradient, diffusible area ratio and rock porosity on the migration of U-238 were investigated. The following insights were obtained: (1) After 100,000 years, U-238 has a very limited diffusion depth in the matrix domain, with a diffusion range of only a few tens of millimeters, whereas it migrates relatively quickly in the fissure domain, with a maximum migration distance of about 1500 m. (2) Under the same migration time and distance, the relative concentration of nuclide U-238 in the fissure domain increases with larger gap width, hydraulic gradient, and diffusible area ratio, but decreases with higher rock porosity. (3) In the same time range, the rock masses with larger gap widths, hydraulic gradients, and diffusible area ratios have larger migration ranges, while those with higher porosities have smaller migration ranges. (4) While selecting a site for diposal of HLWs, it is recommended to choose rock masses in the granite area of Beishan with no fissures or few fissures; additionally, areas with smaller fissure widths, hydraulic gradients, and diffusible area ratios but higher rock porosity should be prioritized. This study can provide important theoretical support for understanding nuclide migration in the future geological disposal of HLWs.

Metoda za postizanje značajnih sila sidrenja unutar ograničenih dubina ugradnje u tanke betonske ploče i ljuske ojačane vlaknima

Contemporary fibre-reinforced concrete provides new opportunities for the design of thin concrete elements with substantial bending strength. To realise the full benefits of reduced weights owing to the reduced structural thickness, new anchorage elements must be developed that can sustain high anchorage forces within limited embedment depths in thin plates. This paper introduces a new anchorage design for concrete plates or shells that provides high tensile forces between 4 and 6 kN within a small embedment depth of 5 mm. The proposed design concept includes a two-stage anchorage mechanism that provides the required tensile strength and ductility for the anchorage. Achieving such anchorage capabilities within the limited embedment depth of thin concrete elements enables the production of lightweight concrete plates and shells.

Blood-brain barrier permeable carbon nano-assemblies for amyloid-β clearance and neurotoxic attenuation

Abnormal amyloid β-protein (Aβ42) fibrillation is a key event in Alzheimer's disease (AD), and photodynamic therapy (PDT) possesses great potential in modulating Aβ42 self-assembly. However, the poor blood-brain barrier (BBB) penetration, low biocompatibility, and limited tissue penetration depth of existing photosensitizers limit the progress of photo-oxidation strategies. In this paper, novel indocyanine green-modified graphene quantum dot nano-assemblies (NBGQDs-ICGs) were synthesized based on a molecular assembly strategy of electrostatic interactions for PDT inhibition of Aβ42 self-assembly process and decomposition of preformed fibrils under near-infrared light. Combining the small-size structure of graphene quantum dots and the near-infrared light-responsive properties of ICGs, the NBGQDs-ICGs could achieve BBB penetration under 808 nm irradiation. More importantly, the neuroprotective mechanism of NBGQDs-ICG was studied for the first time by AFM, which effectively weakened the adhesion of Aβ42 aggregates to the cell surface by blocking the interaction between Aβ42 and the cell membrane, and restored the mechanical stability and adhesion of the neuron membrane. Meanwhile, NBGQDs-ICG promoted phagocytosis of Aβ42 by microglia. In addition, the good biocompatibility and stability ensured the biosafety of NBGQDs-ICG in future clinical applications. We anticipate that such multifunctional nanocomponents may provide promising avenues for the development of novel AD inhibitors.

Intraoperative laparoscopic ultrasound during laparoscopic myomectomy: a narrative review.

Intraoperative laparoscopic ultrasound (IOLUS), a dynamic imaging technique, has emerged as a valuable instrument for guiding surgery in various medical specialties. As IOLUS provides accuracy, improved visualization, and real-time guidance, the integration of IOLUS into many surgical procedures has occurred and IOLUS assists surgeons during advanced procedures. Today, laparoscopic myomectomy has become a prominent surgical procedure in gynecology. Despite its benefits, laparoscopic myomectomy presents certain challenges. The risk of residual fibroids is higher in laparoscopic myomectomy compared to abdominal surgery. The limited depth perception and restricted range of motion can also be obstacles for surgeons, especially when dealing with deeply embedded fibroids. IOLUS has the potential to overcome these limitations. In this study, our aim was to conduct a review of the literature concerning the use of IOLUS during laparoscopic myomectomy.

Development of an Underwater Adaptive Penetration System for In Situ Monitoring of Marine Engineering Geology.

In recent years, offshore wind farms have frequently encountered engineering geological disasters such as seabed liquefaction and scouring. Consequently, in situ monitoring has become essential for the safe siting, construction, and operation of these installations. Current technologies are hampered by limitations in single-parameter monitoring and insufficient probe-penetration depth, hindering comprehensive multi-parameter dynamic monitoring of seabed sediments. To address these challenges, we propose a foldable multi-sensor probe and establish an underwater adaptive continuous penetration system capable of concurrently measuring seabed elevation changes and sediment pore water pressure profiles. The reliability of the equipment design is confirmed through static analysis of the frame structure and sealed cabin. Furthermore, laboratory tests validate the stability and accuracy of the electrical and mechanical sensor measurements. Preliminary tests conducted in a harbor environment demonstrate the system's effectiveness.

Breadth versus depth: whole transcriptome sequencing has reduced sensitivity for detection of clinically relevant fusions compared to RNA comprehensive genomic profiling.

While there is great potential for unbiased next-generation sequencing (NGS) approaches-eg, whole transcriptome sequencing (WTS)-for exploration, discovery, and clinical application in the realm of oncology, there are limitations that should be considered when relying on these methodologies for clinical decision making. When using WTS for the detection of clinically relevant gene fusions in tumor specimens, a key consideration is whether a limited coverage depth (approximately 30-50X) is sufficient for detecting these events, especially in samples with low tumor purity. We demonstrate the reduced sensitivity of both a commercial WTS assay for the detection of clinically relevant fusions in analytical validation control samples and of a research use only (RUO) WTS assay for the detection of clinically relevant fusions in real-world clinical samples compared to RNA comprehensive genomic profiling (CGP). Notably, the RUO WTS assay would not have reported 30% (6/20) of fusions detected using RNA CGP assays in fusion-positive tumor samples, highlighting a potential disadvantage of broader sequencing.

An NSCT-Based Multifrequency GPR Data-Fusion Method for Concealed Damage Detection

Ground-penetrating radar (GPR) is widely employed as a non-destructive tool for subsurface detection of transport infrastructures. Typically, data collected by high-frequency antennas offer high resolution but limited penetration depth, whereas data from low-frequency antennas provide deeper penetration but lower resolution. To simultaneously achieve high resolution and deep penetration via a composite radargram, a Non-Subsampled Contourlet Transform (NSCT) algorithm-based multifrequency GPR data-fusion method is proposed by integrating NSCT with appropriate fusion rules, respectively, for high-frequency and low-frequency coefficients of decomposed radargrams and by incorporating quantitative assessment metrics. Despite the advantages of NSCT in image processing, its applications to GPR data fusion for concealed damage identification of transport infrastructures are rarely reported. Numerical simulation, tunnel model test, and on-site road test are conducted for performance validation. The comparison between the evaluation metrics before and after fusion demonstrates the effectiveness of the proposed fusion method. Both shallow and deep hollow targets hidden in the simulated concrete structure, real tunnel model, and road are identified through one radargram obtained by fusing different radargrams. The significance of this study is producing a high-quality composite radargram to enable multi-depth concealed damage detection and exempting human interference in the interpretation of multiple radargrams.

Controlling η phase distribution and its effects on carburized graded cemented carbides via extrusion additive manufacturing

Functionally Gradient cemented carbides (FGCCs) are promising substrates for polycrystalline diamond composite (PDC). Carburization is the mainstream method for preparing FGCCs, but limited carburizing depth often leads to excessive retention of brittle low-carbon phase (η phase) in the core. This study used Powder Extrusion 3D Printing (PEP) to create dual-layered cemented carbide parts with varying thicknesses of low-carbon outer layers. After pre-sintering and carburization, three new FGCCs were produced. Results showed the η phase was confined to the interface region before carburization. With 3.84 mm carbon-depleted layer, the maximum η phase thickness was 1/10 compared to homogeneous FGCCs, with Co gradient of about 4.5 wt%. The two FGCCs with thinner low-carbon layers had smaller Co gradient with no detected η phase. Additionally, the novel FGCCs displayed enhanced fracture toughness in the core. This study achieved controlled η phase distribution, offering new insights for fabricating high-toughness carburized FGCCs without the η phase.

Roof stability analysis for a shallow-buried cylindrical tunnel in Hoek-Brown rock strata

Roof stability of shallow-buried cylindrical tunnels in rock strata following the generalized Hoek-Brown criterion (GHB) is analyzed in this work. Based on the limit analysis method, a three-dimensional (3D) shallow-buried collapse mechanism for tunnel roofs is developed to derive various stability measures. Optimization codes are programmed to capture the optimal stability measure solutions. The effects of the 3D geometric characteristics, the rock mass strength parameters, and the buried depth on tunnel roof stability are investigated by a parametric analysis. The critical buried depth ratios corresponding to the transition between the shallow-buried and deep-buried tunnel roof collapse mechanisms are also presented. Thereafter a series of stability charts of the required supporting pressure and the factor of safety (FoS) is proposed for design purposes. This study provides a theoretical basis for design and engineering of tunnels with limited buried depth.

Dynamic Analysis of Crane Vessel and Floating Wind Turbine during Temporary Berthing for Offshore On-Site Maintenance Operations

With the increased scale and deployment of floating wind turbines in deep sea environments, jack-up installation vessels are unable to conduct maintenance operations due to limitations in water depth. This has led to the recognition of the advantages of floating cranes in offshore maintenance activities. However, the dynamic coupling between the crane and the floating wind turbine under wave and wind action can result in complex responses, which also relate to complex mooring configurations. The ability to maintain stability during maintenance operations has become a primary concern. In order to address this issue, a method of connecting a floating crane with a floating wind turbine is proposed, simulating the berthing of a floating offshore wind turbine (FOWT) to a crane. Thus, a systematic comparison was conducted with frequency- and time-domain simulation using ANSYS-AQWA software. The simulation results demonstrated the feasibility and dynamic efficiency of this novel berthing approach. Connecting the crane vessel to a floating wind turbine significantly reduced the crane tip movement. Simulations showed that the crane tip movement in the X-, Y-, and Z-directions was reduced by over 30%, which implies that it may be feasible to conduct offshore on-site maintenance operations for the FOWT by using floating crane vessels if the two bodies were properly constrained.