Depth Ratio Research Articles

Improved 3D characterization of in-situ soil desiccation cracking by multi-source data integration

Desiccation cracking is a common and natural phenomenon under a drought climate. The geometric and morphologic characteristics of the crack pattern are critical to understanding the response of soil mechanical and hydraulic properties to drought climate. It is always a big challenge to obtain the refined geometric structure of the in-situ soil desiccation crack network. This study proposes an integrated method named ERT+ for determining the three-dimensional geometry of in-situ soil desiccation crack networks by integrating multi-source data from electrical resistivity tomography (ERT), surface image analysis, and depth investigation. The proposed method was applied to three in-situ expansive soil sites with different crack geometries and soil properties. The results showed that the joint application of ERT with other investigations reduced the ambiguity of interpreting each technique independently. The crack network model characterized the three-dimensional geometric structure of the desiccation crack accurately and quantitatively, verifying the effectiveness and feasibility of the ERT+ method. Field and laboratory experiments showed that heterogeneity in soil properties resulted in different cracking morphologies (width, depth, and width-depth ratio). The crack geometric data suggested that the width-depth ratio of the crack network was related to the cracking modes and the soil properties, indicating the non-homology of different crack networks. In addition, the correction gradients calculated from the ERT+ method also varied with the cracking modes and soil properties, further suggesting the reliability and prospect of the proposed method.

Garlic (Allium sativum) and mushroom (Agaricus bisporus) powder: Investigation of performance, meat quality, serum profile lipid, and intestinal morphology in broilers.

With the ban on the use of antibiotics in poultry nutrition, the opinion of nutritionists turned to their alternatives. Garlic and mushroom are the two important phytobiotic compounds in poultry nutrition. This experiment was done to investigate the effect of garlic powder (GP) and mushroom powder (MP) on the growth performance, meat quality, serum lipid profile, and intestinal morphology of broilers. Five hundred and seventy-six one-day-old male Ross 308 broiler chicks were assigned to eight treatments with six replications based on a completely randomized design in a factorial arrangement of 4*2 with four levels of GP (0.00, 0.50, 1.00, 1.50%) and two levels of MP (0.00, 1.00%). No significant effects of GP and MP on the performance were observed. With increasing levels of GP in the diets, the lightness and redness of breast meat decreased and increased, respectively (p < 0.05). The effect of increasing the amount of GP on the reduction of total cholesterol level was similar in the absence or presence of MP. With increasing levels of GP in the diets, the villus height (VH) and VH to crypt depth ratio (VH: CD) increased. The use of MP in the diets significantly increased VH and VH: CD (p < 0.05). The addition of GP and MP to the broilers' diets did not have any negative effect on the performance. These pharmaceutic herbs improved intestinal morphology. In addition, increasing the level of GP amended the meat color and reduced the level of serum cholesterol.

Stability analysis of tunnel heading in clay with nonstationary random fields of undrained shear strength

The stability problem of a tunnel heading in clay remains a significant challenge in geotechnical engineering. Specifically, when considering the spatial variability of the soil, the stability factor may be influenced by geographically random fields. This study investigates the effect of random fields on a probabilistic analysis of a tunnel heading in undrained clay. The study assumes that the undrained shear strength of the clay increases linearly with depth due to a strength gradient factor. The random adaptive finite element limit analysis is employed to calculate the stability numbers for tunnel headings. Nonstationary random fields with varying vertical correlation lengths are simulated using Monte Carlo simulation technique. The stability analysis takes into account geometry parameters (i.e., cover depth ratio) and nonstationary random field of undrained shear strength parameters. (i.e., strength gradient, coefficient of variation, and vertical correlation length). The results of tunnel face stability using random adaptive finite element limit analysis have also been utilised to assess the probability of design failure over a practical range of deterministic factors of safety. In the context of probabilistic failure analysis, the failure mechanism resulting from varying vertical correlation lengths could influence the probability of design failure. The findings of this study can be of significant interest to tunnel engineering practitioners during the design phase of tunnel heading projects.

Impact of Lactobacillus- and Bifidobacterium-Based Direct-Fed Microbials on the Performance, Intestinal Morphology, and Fecal Bacterial Populations of Nursery Pigs.

Weaning is a critical stage in the swine production cycle, as young pigs need to adjust to sudden and dramatic changes in their diet and environment. Among the various organ systems affected, the gastrointestinal tract is one of the more severely impacted during this transition. Traditionally, challenges at weaning have been managed by prophylactic use of antibiotics, which not only provides protection against diarrhea and other gut dysfunction but also has growth-promoting effects. With banning or major restrictions on the use of antibiotics for this purpose, various alternative products have been developed as potential replacements, including direct-fed microbials (DFMs) such as probiotics and postbiotics. As their efficiency needs to be improved, a continued effort to gain a deeper understanding of their mechanism of action is necessary. In this context, this report presents a study on the impact of a Lactobacillus-based probiotic (LPr) and a Bifidobacterium-based postbiotic (BPo) when added to the diet during the nursery phase. For animal performance, an effect was observed in the early stages (Day 0 to Day 10), as pigs fed diets supplemented with either DFMs were found to have higher average daily feed intake (ADFI) compared to pigs fed the control diet (p < 0.05). Histological analysis of intestinal morphology on D10 revealed that the ileum of supplemented pigs had a higher villus height/crypt depth ratio (p < 0.05) compared to controls, indicating a benefit of the DFMs for gut health. In an effort to further explore potential mechanisms of action, the effects of the DFMs on gut microbial composition were investigated using fecal microbial communities as a non-invasive representative approach. At the bacterial family level, Lactobacillaceae were found in higher abundance in pigs fed either LPr (D10; p < 0.05) or BPo (D47; p < 0.05). At the Operational Taxonomic Unit (OTU) level, which can be used as a proxy to assess species composition, Ssd-00950 and Ssd-01187 were found in higher abundance in DFM-supplemented pigs on D47 (p < 0.05). Using nucleotide sequence identity, these OTUs were predicted to be putative strains of Congobacterium massiliense and Absicoccus porci, respectively. In contrast, OTU Ssd-00039, which was predicted to be a strain of Streptococcus alactolyticus, was in lower abundance in BPo-supplemented pigs on D47 (p < 0.05). Together, these results indicate that the DFMs tested in this study can impact various aspects of gut function.

Comparison of Liquefaction Damage Reduction Performance of Sheet Pile and Grouting Method Applicable to Existing Structures Using 1-G Shaking Table

This study conducted 1-G shaking table tests to compare methods of reducing liquefaction damage during earthquakes. The sheet pile and grouting methods were selected as applicable to existing structures. Model structures were manufactured for two-story buildings. A sine wave with an acceleration of 0.6 g and a frequency of 10 Hz was applied to the input wave. Certain experiments determined the effect of various sheet pile embedded depth ratios and grouting cement mixing ratios on reducing structural damage. The results confirmed that when the sheet pile embedded depth ratio was 0.75, the structure’s settlement decreased by approximately 79% compared to the control model. When the grouting cement mixing ratio was 0.45, the structure’s settlement decreased by approximately 85% compared to the untreated ground. In addition, the sheet pile method suppressed the increase in pore water pressure compared to the grouting method but tended to interfere with the dissipation of pore water pressure after liquefaction occurred. Additionally, comparing the effect of each method on reducing liquefaction damage revealed that the grouting method resulted in less settlement, rotation of the structure, and pore-water-pressure dissipation than the sheet pile method. Overall, the grouting method is more effective in reducing liquefaction damage than the sheet pile method. This study forms a basis for developing a liquefaction-damage reduction method applicable to existing structures in the future.

Reducing Load Transfer to Buried Pipes Through Coupled Use of Geogrid Reinforcement and Sand Rubber Zone in the Backfill Material

A laboratory study, consisting of 21 tests, was conducted to examine precisely the impact of using a sand-rubber mixture with three different ratios of rubber (3, 5, and 7%) in a particular zone within the backfill and a geogrid reinforcement on the pressure transferred to buried pipes from surface loads. The pipe was buried at two different burial depths of 1.5 and 2 times the pipe diameter. Tests were conducted with a geogrid-reinforcement layer placed above and below the sand-rubber zone to determine the optimal performance of the proposed system. The findings from these tests are expected to contribute valuable insights into the development of effective strategies for reducing the impact on buried pipes and enhancing their overall resilience, particularly in the face of increasing surface loading. The results revealed that using a rubber ratio of 5% would present the optimum rubber ratio and using a geogrid layer above the sand-rubber zone would provide additional stability, where the bearing capacity of the system was increased by 33.7%, independent of the pipe burial depth and rubber ratio. Furthermore, the use of a sand-rubber mixture and a geogrid layer contributed to decreasing the pressure transferred to the pipe crown and the deformation of the soil surface, respectively.

Chlomito: a novel tool for precise elimination of organelle genome contamination from nuclear genome assembly.

Accurate reference genomes are fundamental to understanding biological evolution, biodiversity, hereditary phenomena and diseases. However, many assembled nuclear chromosomes are often contaminated by organelle genomes, which will mislead bioinformatic analysis, and genomic and transcriptomic data interpretation. To address this issue, we developed a tool named Chlomito, aiming at precise identification and elimination of organelle genome contamination from nuclear genome assembly. Compared to conventional approaches, Chlomito utilized new metrics, alignment length coverage ratio (ALCR) and sequencing depth ratio (SDR), thereby effectively distinguishing true organelle genome sequences from those transferred into nuclear genomes via horizontal gene transfer (HGT). The accuracy of Chlomito was tested using sequencing data from Plum, Mango and Arabidopsis. The results confirmed that Chlomito can accurately detect contigs originating from the organelle genomes, and the identified contigs covered most regions of the organelle reference genomes, demonstrating efficiency and precision of Chlomito. Considering user convenience, we further packaged this method into a Docker image, simplified the data processing workflow. Overall, Chlomito provides an efficient, accurate and convenient method for identifying and removing contigs derived from organelle genomes in genomic assembly data, contributing to the improvement of genome assembly quality.

Scattering of Oblique Water Waves by Two Vertical Barriers Over Trench-Type Bottom

The problem of scattering of oblique water waves by two surface-piercing vertical thin rigid barriers over a trench-like bottom is investigated within the framework of linear water wave theory. The eigenfunction expansion technique is used to obtain a system of algebraic equations, which is further solved using the algebraic Least squares method. The reflection and transmission coefficients are computed and contrasted with the prior results. Physical characteristics such as surface elevation and horizontal force on both barriers are also determined and depicted graphically against various parameters to see their behavior. It is possible to strategically construct barriers and trench-like bottoms to regulate how waves reflect and propagate. This might mitigate the wave impact on ships, improving the safety, effectiveness and longevity of ships navigating through the channels. The highlights of the given problem include comparing the impacts of different depth ratios and barrier placements, followed by a study of the modulation parameter to evaluate standing wave patterns in the trench region. The specific circumstances for the formation of the standing wave are identified. Hence, understanding this study is critical for safe navigation because standing waves may produce hazardous conditions for boats, making navigation difficult and causing substantial damage.

Use of Periplaneta americana as a Soybean Meal Substitute: A Step towards Sustainable Transformative Poultry Feeds.

Insects are becoming increasingly popular as a sustainable and nutritious alternative protein source in poultry feeds, due to their high protein content, low environmental impact, and efficient feed conversion rates. Using insect-based feeds can reduce the need for traditional protein sources like soybean meal (SBM), which often contribute to environmental issues such as deforestation and high water consumption. The current experiments were devised to assess the impacts of the partial replacement of SBM with the American cockroach Periplaneta americana and black soldier fly Hermetia illucens on the performances, hematology, gut morphometry, and meat quality of male broilers (Ross 308). A total of 350, 1-day-old chicks weighing 40.05 ± 0.27 g were divided into 7 dietary treatments (5 pens/treatment and 10 birds/pen) at random, i.e., a 4, 8, or 12% SMB replacement with P. americana and H. illucens. Soybean meal was used as a basal diet and taken as a control. The results indicated that broilers fed on 12% P. americana or H. illucens showed significant improvements (p < 0.05) in feed conversion ratio, live weight, and daily weight gain. Hematological traits significantly improved (p < 0.05). A gut histology showed increased villus height, villus width, crypt depth, and villus height/crypt depth ratios, indicating improved nutrient absorption. Broiler meat fed on 12% P. americana meal had significantly higher redness and yellowness (p < 0.05). Substituting soybean meal with up to 12% P. americana or H. illucens meal in poultry feed can enhance the broilers' growth performance, hematology, gut morphometry, and meat quality. Hence, these findings imply that P. americana or H. illucens meal are viable and constructive alternative protein sources in poultry nutrition, offering a sustainable approach to meet the increasing demand for animal protein across the world.

Impact of porosity distribution and grading parameters on free vibration of functionally graded beams

This study focuses on investigating the free vibration of porous functionally graded (FG) beams based on neutral surface position and the impact of porosity distribution on the properties and performance of materials. To achieve this, the study assumes that the beam’s material characteristics vary continuously along its thickness direction. The volume fraction of constituents is specified using the modified rule of the mixture, which includes porosity volume fraction with changed porosity patterns across the cross-section. The study uses the parabolic shear deformation theory without shear correction factors to derive the equations of motion by applying Hamilton’s principle. The study employs Navier’s method to obtain analytical results for the free vibration of porous FG beams. To verify the proposed formulation, the study compares the results with relevant findings from the literature. The study also examines the relationship between frequency of vibration and grading parameter in homogeneous porosity distributions, as well as the frequency of vibration in beam structures with different porosity patterns. Additionally, numerical examples are provided to investigate the impact of parameters like power-law index, span to depth ratio, porosity distribution pattern, and porosity volume fraction on the natural frequencies of FG beams.

Linear stability analysis of a Couette-Poiseuille flow: A fluid layer overlying an anisotropic and inhomogeneous porous layer

We investigate the temporal stability analysis of a two-layer flow inside a channel that is driven by pressure. The channel consists of a fluid layer overlying an inhomogeneous and anisotropic porous layer. The flow contains a Couette component due to the movement of the horizontal impermeable upper and lower walls binding the two layers. These walls of the channel move at an identical speed but in opposite directions. The flow dynamics for the porous medium are modelled by the Darcy-Brinkman equations, and the Navier-Stokes equations are employed to describe the motion within the fluid layer. The hydrodynamic instability of infinitesimal disturbance is investigated using Orr-Sommerfeld analysis. The corresponding eigenvalue problem is derived and solved numerically using the Chebyshev polynomial-based spectral collocation method. Results reveal that stability features are strongly affected by the axial and spatial permeability variations of the porous medium. Further, the ratio of the depth of the fluid layer to the porous layer and the strength of the Couette component play a crucial role. The destabilization of the perturbed system is noticed by strengthening the Couette flow component. The combined impact of increasing the anisotropy parameter and depth ratio, decreasing Darcy number, and reducing the inhomogeneity factor stabilizes the system. This facilitates us to have greater control over the instability characteristics of such fluid-porous configuration by suitably adjusting various flow parameters. The outcome will be beneficial in relevant applications for enhancing or suppressing the instability of perturbation waves, as preferable.

Real-time simulation of ship overtake maneuvering at different water depths with a ship motion controller

This study aimed to predict ship trajectories in deep and shallow waters in real-time by properly accounting for the effects of hydrodynamic interactions on ship maneuvering. Ship maneuverability and motion control were investigated under hydrodynamic interactions arising from the effects of water depth, ship speed, and lateral distance between interacting ships on parallel courses. The Maneuvering Modeling Group (MMG) model was used, and the hydrodynamic interaction effect was estimated using an efficient three-dimensional potential-flow code that can run in real time. The influence of water depth on ship maneuverability was analyzed. The ship velocity response to the hydrodynamic interactions and maneuvering motion was simulated during the overtaking process of two ships at a range of water depths, lateral distances, and speeds. The findings suggest that, in shallow waters, changing the heading of the ship becomes more difficult, and the course deviation associated with the overtaking maneuver of two ships also increases. A conventional proportional-integral-derivative (PID) controller was employed for course-keeping. When the ratio of the water depth to ship draft was less than 2.0, the PID controller continued to perform effectively for the overtaking ship. For the overtaken ship, the effectiveness of the controller was diminished owing to the relatively low rudder effect at slow speeds.

A Semi-Analytical Solution of Two-Dimensional Unsteady Groundwater Flow Outside a Long-Strip Excavation Pit with a Cut-Off Wall

In deep excavation engineering, the implementation of cut-off walls stands as a crucial measure to ensure structural support stability. However, the existing theories for dewatering design often overlook the variations in cut-off wall penetration depths, potentially compromising the efficacy of groundwater control strategies. Addressing this gap, this study conducts a comprehensive investigation into the dynamics of groundwater levels within confined aquifers during the dewatering process of strip excavation pits with cut-off walls. Central to this inquiry is the conceptualization of the entire excavation pit as a singular large-diameter well, with the open part beneath the cut-off wall in the confined aquifer serving as a constant-flux boundary. Employing an advanced analytical modeling approach, the study formulates a robust framework to describe the intricate interplay of unsteady groundwater flow phenomena. Leveraging the techniques of the Laplace and finite cosine transform methods, a semi-analytical solution is derived to elucidate groundwater drawdown patterns over time. The validation of the proposed solution against finite element method results underscores its fidelity and applicability. The parametric analysis reveals a dynamic evolution in drawdown characteristics within the confined aquifer, transitioning from initially cone-shaped distributions to more linear profiles that eventually stabilize with prolonged dewatering. This evolution is governed by the aquifer’s inherent anisotropy and the barrier effect exerted by the depth of cut-off wall penetration. The parametric research also underscores the critical role of lateral boundary distance in influencing groundwater drawdown patterns. The presented solutions can be used to identify optimal penetration depth ratios tailored to specific parameters, thereby offering insights for optimizing dewatering strategies for deep excavation groundwater control. Moreover, a case study was included in this study using the proposed analytical solution, and a comparison was made with field data to validate the practical applicability of the approach.

Comparative evaluation of solid particle erosion resistance in milled carbon fiber‐reinforced basalt fiber epoxy composites: Impact of abrasive shape variations

AbstractThe solid particle erosive wear performance of basalt fiber‐reinforced epoxy composites with the incorporation of different percentages of milled carbon fiber fillers (0–10 wt%) is evaluated under various abrasive materials (garnet and ceramic beads) and impingement angles (30° and 90°). Erosion tests have been carried out following ASTM G76 standards using a factorial design method. The data indicate that the erosion rates, crater depths, and areas of craters are all strongly dependent on erodent material type and milled carbon fiber filler ratio. Compared to ceramic beads, garnet abrasives caused severe erosion, with erosion rates reaching approximately 500 mg/g at a 90° impingement angle without milled carbon fiber fillers. Erosion by both abrasives was significantly reduced by the introduction of milled carbon fiber fillers into the basalt fiber composites, with the erosion rate decreasing to around 100 mg/g with 3 wt% milled carbon fiber fillers. The maximum crater depth was also influenced; garnet abrasives produced craters as deep as 1000 μm without fillers at 90°, which was reduced to 451 μm with 3 wt% milled carbon fiber fillers when ceramic beads were used. Of the three factors for the erosion rate and crater depth, inorganic erodent material and ratio of carbon fiber filler were prominent, but the impingement angle effect was much smaller. Among the three factors for the erosion rate and crater depth, erodent material and carbon fiber filler ratio were prominent, while the impingement angle effect was significantly less.Highlights The garnet abrasives cause more severe erosion than ceramic beads at 90°. Composites exhibit optimal erosion resistance with 3–5 wt% milled carbon fiber fillers. Filler ratio and erodent material type significantly impact erosion rates and depths. Factors affecting wear performance identified using factorial design and ANOVA.

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.

Instability, bifurcation and nonlinear dynamics of Poiseuille flow in fluid overlying an anisotropic and inhomogeneous porous domain

The present study focuses on the finite amplitude analysis of Poiseuille flow in an anisotropic and inhomogeneous porous domain that underlies a fluid domain. The nonlinear interactions are studied by imposing finite amplitude disturbances to the Poiseuille flow. The former interactions in terms of modal amplitudes dictate the fundamental mode, the distorted mean flow, the second harmonic and the distorted fundamental mode. The harmonics are solved progressively in increasing order of the least stable mode obtained from the linear theory to ascertain the cubic Landau equation, which in turn helps to determine the bifurcation phenomena. The presented weakly nonlinear theory predicts the existence of subcritical transition to turbulence of Poiseuille flow in such superposed systems. In general, on moving away from the bifurcation point, it is found that a decrease in the value of inhomogeneity (in terms of Ai), Darcy number (δ) and an increase in the value of depth ratio (dˆ; the ratio of fluid domain thickness to that of porous domain) favours subcritical bifurcation. For the considered variation of parameters, the bifurcation, either subcritical or supercritical, remains the same irrespective of the value of media anisotropy (ξ) in the vicinity of the bifurcation point except for dˆ=0.2,Ai=1. In such a situation, subcritical (supercritical) bifurcation is witnessed for ξ=0.001,0.01,0.1 (1,3). Furthermore, in contrast to isotropic and homogeneous porous media, both subcritical and supercritical bifurcations are observed when moving away from the bifurcation point. A correspondence between the type of mode via linear theory and the type of bifurcation via nonlinear theory is witnessed, which is further affirmed by the secondary flow patterns. Finally, the presented theoretical results reveal an early onset of subcritical transition to turbulence in comparison with isotropic and homogeneous porous media.

Effects of wheat-based fermented liquid feed on growth performance, nutrient digestibility, gut microbiota, intestinal morphology, and barrier function in grower-finisher pigs.

Fermented liquid feed (FLF) can improve dietary nutrient absorption levels, degrade anti-nutrient factors in diets, and increase beneficial bacteria abundance in animal guts. However, few systematic studies have been conducted on WFLF in pigs. The present study evaluates the effects of WFLF on the growth performance, nutrient digestibility, gastric volume, intestinal morphology, intestinal health, intestinal barrier function, serum biochemical immunity, gut microbiota, and intestinal microbial diversity of grower-finisher pigs. In total, 80 weaned pigs were randomly allocated to two treatment groups based on their initial body weight: a basal diet with pellet dry feeding (CON) and a basal diet with wheat-based fermented liquid feed (WFLF), with four replicate pens per group. The experiment lasted 82 d. Compared with CON pigs, those fed WFLF were heavier significantly at 60-82 d and had significantly higher average daily feed intake, average daily gain, and gain: feed ratio at 60-82 d and 1-82 d. WFLF pigs had significantly greater jejunum, total tract, and ileal digestibility for all nutrients and amino acids, excluding arginine, than CON pigs. WFLF intake influenced villus height, villus height: crypt depth ratio of the anterior segment of the jejunum(A-jejunum), crypt depth, and redox potential of the posterior segment of the jejunum (P-jejunum) while significantly affecting body weight. Additionally, FLF improved gastric capacity significantly. Furthermore, mRNA expression of occludin and claudin-1 in the mucosa of the ileum and jejunum was significantly higher in WFLF pigs than in CON pigs. WFLF increased serum concentrations of alanine transaminase and reduced low-density lipoprotein cholesterol, total cholesterol, and total bile acid content. The alpha diversity (Shannon and Simpson indices) in the stomachs of WFLF pigs was significantly higher than in CON pigs. Microbial diversity in the stomach, ileum, and cecum, as well as the abundance of lactic acid bacteria, were increased in WFLF pigs compared to CON pigs. In conclusion, WFLF intake may positively influence intestinal ecology by improving digestive tract structure, upregulating intestinal barrier-related genes, and improving intestinal morphology to enhance intestinal digestive function and health. Collectively, the present study shows that WFLF intake can increase growth performance while maintaining beneficial nutrient digestibility in grower-finisher pigs.

Flexural and fracture performance of fiber reinforced self compacting alkali activated concrete– A DOE approach

Owing to their much-reduced carbon footprint and lower embodied energy, compared to conventional Portland Cement (OPC-based) Concrete mixes, Alkali Activated Concrete (AAC) mixes represent a pivotal advancement towards achieving sustainability goals. The fracture properties were investigated using Three-Point Bending Tests (3-PBT) under the mode I failure mechanism. This study utilises Taguchi analysis to analyse and optimise Self-Compacting Alkali-Activated Concrete (SAAC), focusing mainly on its flexural strength and fracture characteristics. An L-16 orthogonal array of experiments with three input parameters − replacement of Blast Furnace Slag (BFS) with Fly ash (FA) (0 %, 30 %, 40 %, and 50 %), Steel Fibers (SF) volume content (0 %, 0.25 %, 0.5 % and 0.75 %) and Notch to Depth (a0/d) ratio (0.2,0.3,0.4 and 0.5), at four levels each, was adopted. The Work of Fracture Method (WFM) and Double K Fracture Criterion (DKFC) were utilised to determine the Fracture Energy (GF) and fracture toughness, respectively. The results obtained from all the sixteen mixes showed that the F0-S0.75-N0.5 mix demonstrated better values in several parameters, such as flexural strength of 7.82 MPa,KICini of 0.928 MPa√m, KICuns of 6.99 MPa√m and KICini/ KICuns of 0.133. A maximum GF of 2350 N/m was obtained with F50-S0.75-N0.2 mix. However, all the inferior values of these parameters were observed with F50-S0-N0.5 mix, which recorded a flexural strength of 4.90 MPa, KICini of 0.612 MPa√m,KICuns of 1.16 MPa√m, KICini/ KICuns of 0.528 and GF of 125 N/m. Through Taguchi analysis, the optimal combination for flexural strength was identified as FA 0 %, SF 0.75 %, and a0/d 0.5 and for both Initial Fracture Toughness (KICini) and Unstable Fracture Toughness (KICuns) at FA 0 %, SF 0.75 % and a0/d 0.4. For both the ratio of initial to unstable fracture toughness (KICini/ KICuns) and fracture energy (GF), the optimum combination was FA 0 %, SF 0.75 % and a0/d 0.2. Furthermore, the results indicate that FA significantly influences KICini, while SF predominantly affects all other parameters. The predictive performance of the regression equations demonstrates good agreement with experimental outcomes.

Calculation Method of New Assembled Corrugated Steel Initial Support Structure of Highway Tunnel

The assembled corrugated steel initial support structure is a new prefabricated structure in highway tunnel engineering, achieving a balance between economy and safety. This study proposes a simplified calculation method and elucidates the mechanical mechanisms of assembled corrugated steel initial support structures. Firstly, the stiffness characteristics of corrugated steel plates were studied based on full-scale tests. A general equivalent stiffness coefficient table was established. Numerical simulations of corrugated steel flange joints were conducted to explore their bending mechanical properties. A two-stage rotational stiffness model for corrugated steel flange joints was proposed. Finally, a plane strain-spring simplified calculation method for the assembled corrugated steel initial support structure was developed, and the monitoring data from the Qipanshan Tunnel validated the correctness and reliability of the proposed method. The results demonstrate that (1) the plane strain-spring simplified model consists of the planar strain equivalent calculation method for corrugated steel plates and the two-line stiffness equivalent spring of the corrugated steel flange joint. The simplified model was validated as effective by monitoring data. (2) Corrugated steel plates exhibit two stages under loading, namely gap elimination and elastic stages. The elastic stage stiffness of corrugated steel plates decreases with increasing ratio of depth to pitch (RDP), positively correlating with plate thickness when the RDP exceeds 0.333 and otherwise negatively correlated. (3) Corrugated steel lining flange joints exhibit distinct elastic and plastic stages in their linear moment–rotation curves under loading.

Dietary vitamin B6 supplementation alleviates heat stress-induced intestinal barrier impairment by regulating the gut microbiota and metabolites in broilers

Heat stress (HS) brings great challenges to the poultry industry. Vitamin B6 (VB6) is an essential micro-nutrient for animals to maintain normal physiological functions and possesses antioxidant and anti-inflammatory properties. This study aimed to explore the effect of VB6 on alleviating HS-induced intestinal barrier impairment in broilers. A total of 250 broilers (609.76 ± 0.34 g) were randomly allocated to 5 groups with 5 replicate cages of 10 birds each. The broilers in thermoneutral (TN) group were raised in thermoneutral conditions (23 ± 1°C) and fed with a basal diet. The birds in other four groups were housed under cycle high temperature (34 ± 1°C for 8 h/d) from d 21 to 35 and fed with the basal diet (HS group) or basal diet supplemented with 6, 12, or 24 mg/kg VB6 (HB-6, HB-12, HB-24 groups). The results showed that HS reduced the growth performance, increased ileum inflammatory cytokines levels, and impaired the gut barrier function (P < 0.05). Compared to the HS group, final body weight, average daily gain, and average daily feed intake, and the feed conversion ratio were improved by VB6 supplementation. The diamine oxidase, interleukin (IL)-1β, tumor necrosis factor-α, IL-18, IL-10, and interferon-γ levels were reduced by VB6 supplementation (P < 0.05). Moreover, VB6 supplementation linearly or quadratically enhanced villus height and villus height-to-crypt depth ratio of duodenum and jejunum, and decreased crypt depth of duodenum and ileum. The mRNA expression of Occlaudin, ZO1, Mucin2, Mucin4, E-cadhein, and β-catenin were increased by VB6 treatment (P < 0.05). Furthermore, dietary VB6 altered the diversity and community of gut microbiota (P < 0.05). A total of 83 differential metabolites associated with the amelioration of VB6 were identified, which were primarily enriched in glycerophospholipid metabolism, caffeine metabolism, and glutathione metabolism pathway. Collectively, VB6 may improve the growth performance and intestinal barrier function of heat-stressed broilers by regulating the ileal microbiota and metabolic homeostasis.