bluuebunny/crossref_metadata_2025_split huggingface dataset:
Numerical investigation on the influence of secondary flaw lengths on the mechanical characteristics and cracking behaviour of red sandstone containing orthogonal cross flaws
Authors: Xu Rongchao , Dou Baoyang , Zhao Ying , Peng Wenbin , Li Zhen 
Published: April 2024

AbstractFlaw length has a significant effect on the cracking behaviour of fractured rock. PFC2D was used to simulate the uniaxial compression of red sandstone samples with secondary flaw lengths L2 of 0 mm, 5 mm, 10 mm, 15 and 20 mm under different primary flaw angles α(α = 0°, 15°, 30°, 45°, 60°, 75°, and 90°). Based on the simulation results, the effects of the secondary flaw length on the mechanical parameters, crack initiation location and crack evolution process of the fractured rock were analysed. Then, a method for judging the initiation location of the first cracks was proposed. Finally, the characteristics of the particle displacement field at preexisting flaw tips during first and secondary crack initiation were analysed. The results of this study are helpful for more deeply understanding the cracking behaviour of fractured rock.
Semi‐implicit material point method for simulating infiltration‐induced failure of unsaturated soil structures
Authors: Hidano Soma , Yamaguchi Yuya , Takase Shinsuke , Moriguchi Shuji , Kaneko Kenji , Terada Kenjiro 
Published: April 2024

AbstractThis study presents a semi‐implicit MPM to adequately characterize the mechanical behavior of unsaturated soil based on Biot's mixture theory. To represent the dependency of the degree of saturation on the suction, we employ the VG model along with a soil‐water characteristic curve, which determines a functional form of permeability called the Mualem model. Hencky's hyperelastic model and the Drucker‐Prager model assuming nonassociativity are adopted for elastic and plastic deformations, respectively. The novelty of this study is the incorporation of the fractional‐step method into the MPM framework so that the pore water pressure is obtained by implicitly solving the pressure Poisson's equation, which reduces numerical instability and improves computational efficiency. Also, because the drag force between solid and liquid phases is evaluated using the intermediate velocity of pore water relative to the intermediate velocity of solid skeleton, the time increment can be chosen without considering the magnitude of water permeability. In addition, to suppress “odd‐even” oscillation, we employ a sub‐grid method in which two grids with different spatial resolutions are used for the velocities and pore water pressure. Furthermore, considering the advantages and disadvantages of two different interpolation schemes for pore water pressure, we suggest switching the schemes depending on the model conditions. Several numerical examples are presented to demonstrate the performance of the proposed method. Specifically, unidirectional consolidation and leak flow analyses are performed for verification purposes, followed by validation analysis of a model experiment of infiltration‐induced landslides.
Numerical modelling of thermal jet assisted rock cutting with double PDC cutters
Authors: Saksala Timo 
Published: April 2024

AbstractPreconditioning of rock for drilling operations is a potential method to facilitate the mechanical breakage and mitigate the tool wear. This paper numerically investigates one such preconditioning technique, namely, the thermal jet assisted rock cutting. For this end, a numerical method for solving the governing thermo‐mechanical problem is developed and validated. The continuum approach is chosen to describe the rock failure, being based on a damage‐viscoplasticity model with the Drucker–Prager yield surface and the modified Rankine surface as the tensile cut‐off. In the damage part, separate scalar damage variables are employed for tension and compression. The cutters are modelled as rigid bodies and their interaction with the rock is modelled by imposing contact constraints by the forward increment Lagrange multiplier method, which is compatible with the chosen explicit time integration scheme. A damage‐based erosion criterion is applied to remove the contact nodes surrounded by heavily damaged elements. The thermal jets are modelled with a moving external heat flux boundary condition. The global thermo‐mechanical problem is solved with a staggered approach explicitly in time while applying mass scaling to increase the critical time step. The novel 3D numerical simulations involving two cutters demonstrate the capabilities of the method with a special emphasis on cutter‐thermal jet configurations. Therefore, the present method provides a potential tool for the bit design in thermal jet assisted drilling.
Analysis of laterally loaded floating piles using a refined Tajimi model
Authors: Zheng Changjie , Kouretzis George , Ding Xuanming 
Published: April 2024

AbstractThis paper presents a novel mathematical model for the analysis of laterally loaded floating piles embedded in a homogeneous soil layer of finite thickness. The governing equations of the soil surrounding the pile are established by treating soil as a Tajimi‐type continuum, and their solution yields a closed‐form expression that provides the lateral force developing to resist pile deflection. Accordingly, analytical expressions are obtained for the swaying, swaying‐rocking and rocking pile head stiffness, as well as for pile displacement and rotation along its length. The derived expressions are functions of parameters that have direct physical meaning, such as pile and soil elastic stiffness. As such, they pose as an attractive alternative to numerical methods for the low‐cost calibration of Winkler‐based model empirical parameters associated with small pile deflections. The presentation concludes with a parametric study focused on exploring the sensitivity of pile stiffness and deformations to the main problem parameters, and on highlighting differences in the lateral response of floating and end‐bearing piles.
A first‐order hyperbolic arbitrary Lagrangian Eulerian conservation formulation for non‐linear solid dynamics
Authors: Di Giusto Thomas B. J. , Lee Chun Hean , Gil Antonio J. , Bonet Javier , Giacomini Matteo 
Published: April 2024

SummaryThe paper introduces a computational framework using a novel Arbitrary Lagrangian Eulerian (ALE) formalism in the form of a system of first‐order conservation laws. In addition to the usual material and spatial configurations, an additional referential (intrinsic) configuration is introduced in order to disassociate material particles from mesh positions. Using isothermal hyperelasticity as a starting point, mass, linear momentum and total energy conservation equations are written and solved with respect to the reference configuration. In addition, with the purpose of guaranteeing equal order of convergence of strains/stresses and velocities/displacements, the computation of the standard deformation gradient tensor (measured from material to spatial configuration) is obtained via its multiplicative decomposition into two auxiliary deformation gradient tensors, both computed via additional first‐order conservation laws. Crucially, the new ALE conservative formulation will be shown to degenerate elegantly into alternative mixed systems of conservation laws such as Total Lagrangian, Eulerian and Updated Reference Lagrangian. Hyperbolicity of the system of conservation laws will be shown and the accurate wave speed bounds will be presented, the latter critical to ensure stability of explicit time integrators. For spatial discretisation, a vertex‐based Finite Volume method is employed and suitably adapted. To guarantee stability from both the continuum and the semi‐discretisation standpoints, an appropriate numerical interface flux (by means of the Rankine–Hugoniot jump conditions) is carefully designed and presented. Stability is demonstrated via the use of the time variation of the Hamiltonian of the system, seeking to ensure the positive production of numerical entropy. A range of three dimensional benchmark problems will be presented in order to demonstrate the robustness and reliability of the framework. Examples will be restricted to the case of isothermal reversible elasticity to demonstrate the potential of the new formulation.
Weight management in rural health clinics: Results from the randomized midwest diet and exercise trial
Authors: Gorczyca Anna M. , Washburn Richard A. , Ptomey Lauren T. , Mayo Matthew S. , Krebill Ron , Sullivan Debra K. , Gibson Cheryl A. , Stolte Sarah , Donnelly Joseph E. 
Published: April 2024

AbstractIntroductionRural living adults have higher rates of obesity compared with their urban counterparts and less access to weight management programs. Previous research studies have demonstrated clinically relevant weight loss in rural living adults who complete weight management programs delivered by university affiliated interventionists. However, this approach limits the potential reach, adoption, implementation, and maintenance of weight management programs for rural residents. Weight management delivered through rural health clinics by non‐physician clinic associated staff, for example, nurses, registered dieticians, allied health professionals, etc. has the potential to improve access to weight management for rural living adults. This trial compared the effectiveness of a 6‐month multicomponent weight management intervention for rural living adults delivered using group phone calls (GP), individual phone calls (IP) or an enhanced usual care control (EUC) by rural clinic associated staff trained by our research team.MethodsRural living adults with overweight/obesity (n = 187, age ∼ 50 years 82% female, body mass index ∼35 kg/m2) were randomized (2:2:1) to 1 of 3 intervention arms: GP, which included weekly ∼ 45 min sessions with 7–14 participants (n = 71), IP, which included weekly ∼ 15 min individual sessions (n = 80), or EUC, which included one‐45 min in‐person session at baseline.ResultsWeight loss at 6 months was clinically relevant, that is, ≥5% in the GP (−11.4 kg, 11.7%) and the IP arms (−9.1 kg, 9.2%) but not in the EUC arm (−2.6%, −2.5% kg). Specifically, 6 month weight loss was significantly greater in the IP versus EUC arms (−6.5 kg. p ≤ 0.025) but did not differ between the GP and IP arms (−2.4 kg, p > 0.025). The per participant cost per kg. weight loss for implementing the intervention was $93 and $60 for the IP and GP arms, respectively.ConclusionsWeight management delivered by interventionists associated with rural health clinics using both group and IP calls results in clinically relevant 6 months weight loss in rural dwelling adults with overweight/obesity with the group format offering the most cost‐effective strategy.Clinical trial registration: ClinicalTrials.gov (NCT02932748).
Coordination as the flagship to the efficacy of humanitarian aid: Research on the influence of different coordination types on the efficacy of humanitarian aid operations in Africa
Authors: Ruiter David , de Vries Michiel S. 
Published: April 2024

AbstractAnnually, global populations need humanitarian aid due to various crises. Whilst numerous actors aim to provide assistance in these critical situations, this aid is often deemed ineffective due to duplication of efforts and a failure to ensure that all individuals in need are reached. This research aims to raise awareness of the significance of coordination in this field, as well as setting the stage for further research of issues and potential solutions within this policy domain. While “Coordination” is a widely accepted term that is regarded as a comprehensive solution, it lacks specificity regarding the type of coordination required. This research uses a meta‐evaluation to contend that despite extensive research on coordination within humanitarian interventions, there is still considerable room for improvement in this area. The findings, drawing on evaluations of humanitarian assistance in Africa, indicate that the success of coordination efforts varies depending on the type of coordination employed. They emphasize that humanitarian coordination positively impacts effectiveness, but this influence is contingent on the operationalization of the concept and the presence of various conditional factors. Several recommendations follow from these findings, including improvements on information exchange, short‐ and long‐term strategies and joint resource mobilization.
Nano clay treated jute fiber reinforced epoxy composites: Thermo‐kinetic, morphological and mechanical analysis
Authors: Yadav Brijesh Kumar , Vandna  , Gond Devendra Kumar , Yadav Vijay Laxmi 
Published: April 2024

AbstractCurrent scientific research prioritizes sustainable and cost‐effective materials due to the depletion of traditional non‐renewable sources. Natural fiber reinforced composite materials emerge as promising solutions. However natural fibers being hydrophilic in nature are less compatible with hydrophobic epoxy matrix, to address this issue nano clay treatment of jute fibers have been done and epoxy composites were formed with their reinforcement. Through FT‐IR, thermal, mechanical, and morphological analyses, both treated and untreated composites are evaluated. The treated composites exhibit a notable 19% increase in activation energy (FWO and KAS methods) compared to untreated ones (217.5–259 KJ/mol), indicating improved thermal stability. Moreover, the treated composite demonstrates a significant 38% boost in tensile strength (30–41.4 MPa) and a 28% enhancement in flexural strength (50–64 MPa), highlighting the impact of alkali‐nano clay treatment in reinforcing structural integrity. These enhancements suggest the potential applicability of composites manufactured with alkali‐nano clay treated jute fibers (A/NC/J fiber) across various industries. This innovative approach not only bridges the gap in sustainable material development but also offers cost‐effective solutions for commercial utilization.Highlights
Analyzed alkali‐nano clay treatment effects on jute fiber in epoxy composites.
Studied activation energy (FWO, KAS) for untreated and treated composites.
Treated composites show a 19% increase in activation energy: Thermal stability
Significant improvements: 38% rise in tensile, 28% increase in flexural strength.
The role of arousal in the estimation of time‐to‐collision of threatening stimuli
Authors: Li Caiwen , Xuan Yuming , Bruns Patrick , Fu Xiaolan 
Published: April 2024

AbstractThe accurate estimation of time‐to‐collision (TTC) is essential for the survival of organisms. Previous studies have revealed that the emotional properties of approaching stimuli can influence the estimation of TTC, indicating that approaching threatening stimuli are perceived to collide with the observers earlier than they actually do, and earlier than non‐threatening stimuli. However, not only are threatening stimuli more negative in valence, but they also have higher arousal compared to non‐threatening stimuli. Up to now, the effect of arousal on TTC estimation remains unclear. In addition, inconsistent findings may result from the different experimental settings employed in previous studies. To investigate whether the underestimation of TTC is attributed to threat or high arousal, three experiments with the same settings were conducted. In Experiment 1, the underestimation of TTC estimation of threatening stimuli was replicated when arousal was not controlled, in comparison to non‐threatening stimuli. In Experiments 2 and 3, the underestimation effect of threatening stimuli disappeared when compared to positive stimuli with similar arousal. These findings suggest that being threatening alone is not sufficient to explain the underestimation effect, and arousal also plays a significant role in the TTC estimation of approaching stimuli. Further studies are required to validate the effect of arousal on TTC estimation, as no difference was observed in Experiment 3 between the estimated TTC of high and low arousal stimuli.
The synthesis of polymers with ultra‐high molecular weight by combining ROMP and acyclic metathesis reaction
Authors: Xie Linzhi , Zhou Yunfeng , Zhu Xiaoming , Huang Geng , Xiao Lifen , Li Wei 
Published: April 2024

AbstractRing opening metathesis polymerization (ROMP) is widely used to prepare functional materials with various topological structures. However, it is difficult to prepare polymers with ultra‐high molecular weight (UHMW) directly. We found a new method to prepare UHMW polymers by combining ROMP and acyclic metathesis reaction. First, monomer NB‐2OH was polymerized by ROMP with different feed ratio of NB‐2OH/G3, and obtained well‐defined polymers P(NB‐2OH)n (n = 50, 200, and 463). Then acyclic metathesis reaction was used to synthesize UHMW polymers. The results indicated that polymer P(NB‐2OH)z with higher molecular weight (Mw = 6067.3 kg mol−1) and narrower distribution (PDI = 1.58) could be obtained at 80°C for 5 min, when P(NB‐2OH)463 was used as raw material with H2SO4/G3 = 10/1. Compared with polymer P(NB‐2OH)1990 (Mw = 5343.1 kg mol−1, PDI = 1.61) prepared by ROMP directly, the new method tremendously shortens reaction time, lowers the requirement for the purity of monomer and produces UHMW polymers with narrower distribution. The compositions of prepared polymers were also confirmed clearly by post‐modification and 1H NMR characterization.
Static ignition hazards with plastic containers
Authors: Snyder Mike , Robinson Kelly 
Published: April 2024

AbstractPlastic containers present unique challenges in flammable liquid service, as most plastics are highly electrically insulating, cannot be grounded, and can easily accumulate electrostatic charges. These electrostatic charges result in elevated risks of electrostatic ignitions where the potential for ignitable mixtures exists, including unique and different exposures on the inside and outside surfaces of plastic containers. In this primer, four specific ignition risks are overviewed: (1) flow electrification, (2) splash filling, (3) triboelectrification, and (4) charge accumulation on workers.
Sequential sampling for functional estimation via Sieve
Authors: Benevento Alessia , Ahadi Pouya , Gupta Swati , Pacella Massimo , Paynabar Kamran 
Published: April 2024

AbstractSequential sampling methods are often used to estimate functions describing models subjected to time‐intensive simulations or expensive experiments. These methods provide guidelines for point selection in the domain to capture maximum information about the function. However, in most sequential sampling methods, determining a new point is a time‐consuming process. In this paper, we propose a new method, named Sieve, to sequentially select points of an initially unknown function based on the definition of proper intervals. In contrast with existing methods, Sieve does not involve function estimation at each iteration. Therefore, it presents a greater computational efficiency for achieving a given accuracy in estimation. Sieve brings in tools from computational geometry to subdivide regions of the domain efficiently. Further, we validate our proposed method through numerical simulations and two case studies on the calibration of internal combustion engines and the optimal exploration of an unknown environment by a mobile robot.
Transport Spectroscopy of Donor/Quantum Dot Interactive System in Silicon Nano‐Transistors
Authors: Chakraborty Soumya , Yadav Pooja , Moraru Daniel , Samanta Arup 
Published: April 2024

AbstractDonor‐atom‐based nano‐devices in silicon represent a breakthrough for individual control of electrons at atomic scale. Here, a finite‐bias characterization of electrical transport through such a device, fabricated on a silicon‐on‐insulator (SOI) wafer with low phosphorus (P) doping, is presented. In this device, multiple quasi‐periodic current peaks are observed at low temperatures in the electrical transfer characteristics. Such behavior of the transport characteristics is generally observed in devices having high doping concentration or with selective doping in the channel region to form a multi‐donor cluster quantum dot. However, in the present device donor–cluster formation is highly improbable owing to low doping concentration. The observed electrical transport characteristics of the device are explained with a model of two non‐interacting donors coupled in series with an unintentionally larger quantum dot, likely formed within the channel due to roughness. Theoretical simulation is also presented here for such a circuit supporting the experimental observations.
Respiratory maze: An anatomical variant of tracheal bronchus
Authors: Gullapalli Dedeepya , Tangutoori Shivendra , Ganti Subramanya Shyam 
Published: April 2024

Key messageThis case highlights an uncommon anatomical variation in the airway known as Tracheal bronchus, which can sometimes lead to recurrent pneumonia. It is crucial to exercise caution during intubation in patients with this condition.
Effect of corrugated steel angle on the damage characteristics and anti‐explosion performance of corrugated steel–concrete composite structures
Authors: Cao Kelei , Fu Qiaofeng , Zhang Jianwei , Tang Changxing , Huang Jinlin , Wang Chao , Bai Weifeng 
Published: April 2024

SummaryA three‐dimensional refined numerical simulation model of a corrugated steel–concrete slab composite structure under contact explosion load was established by the finite element model and smoothed particle hydrodynamics(FEM‐SPH) coupling method to explore the anti‐knock properties of corrugated steel reinforced concrete slabs with different angles. The effects of corrugated steel angle on the dynamic response, damage evolution characteristics, damage mode, anti‐knock property, and propagation mechanism of the shock wave in the composite structure were investigated, and the damage prediction and anti‐knock property evaluation of the composite structure were carried out. The results show that the simulation results of the mid‐span displacement of the corrugated steel are consistent with the experimental results, and the maximum error is 2.3%, which verifies the effectiveness of the contact explosion simulation process. The mid‐span displacement, peak stress, acceleration at the center point, and energy absorption value of 90° corrugated steel are 17.9%, 70.5%, 88.6%, and 59.4% lower than those of 30° corrugated steel. The damage range of the composite structure gradually decreases with increasing angle of the corrugated steel. The failure volume of the concrete slab reinforced by corrugated steel with different angles decreases with increasing angle of the corrugated steel, and the energy absorption value of the composite structure increases with increasing of angle of the corrugated steel, mainly because the corrugated steel increases the number of reflections of the stress wave. The research results can provide a theoretical basis for the application of composite structures in the field of structural anti‐explosion protection.