bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Fine Aggregates and Test Settings on the Self-sensing Response of Cement-Based Composites with Carbon Nanotubes as Conductive Filler
Authors: dos Santos T. C. , Carísio P. A. , Martins A. P. S. , Paiva M. D. M. , Gomes F. M. P. , Reales O. A. M. , Toledo Filho R. D. 
Published: July 2023

AbstractCement-based self-sensing composites with carbon nanotubes (CNT) have attracted attention due to their multifunctional properties and great potential for their application in the smart monitoring of concrete structures. In this study, the self-sensing properties of one paste and three mortars containing 0.50 and 0.75 wt% of CNT, and 1.5 and 1.0 sand/cement ratio were investigated, aiming to evaluate their impact on the piezoresistive response of the composites. The inclusion of sand in the cement paste with CNT led to a reduced gauge factor and a higher electrical noise response. The inert aggregates modified the compressive loading mechanical response of the composites and possibly acted as barriers to electronic mobility, by increasing the CNT conductive paths’ tortuosity or even interrupting them. The mortar containing 0.50% of CNT showed a higher electrical resistivity and, at the same time, greater sensitivity and a more linear self-sensing response than the one with 0.75% CNT, which can be explained by the CNT content being closer to its percolation threshold in the first. In this way, a lower CNT concentration generated a conductive network with a higher capacity to be rearranged under loading, generating significant changes in resistivity, but a higher CNT concentration presented a more stable and conductive network. The results suggested that both the conductive and non-conductive phases affect the detection performance of the composites and, therefore, must be dosed appropriately. Additionally, the test setup modifications positively affected the self-sensing response signal, which is particularly useful to reduce the deleterious effects of the sand additions in the matrix. This overall approach can make the use of self-sensing mortars in structural monitoring a viable option.
A New Dispersion Strategy to Achieve High Performance Graphene-Based Cement Material
Authors: Zhang Z. , Yao Y. , Liu H. , Zhuge Y. , Zhang D. 
Published: July 2023

AbstractThe addition of graphene and its derivatives can enhance the mechanical and functional properties of cement-based composites, but most of the current technologies have limited dispersion and are costly. The creation of a cost-effective graphene-reinforced cement material with uniform graphene dispersion remains difficult. We used glucose as an economical carbon source to induce the in-situ formation of graphene on cement particles. Our proposed method is approximately 80% less expensive than commercial techniques. Evaluation of the microscopic morphology demonstrated uniform distribution of graphene in the cement matrix, which improved the mechanical properties of the cement paste. The compressive strengths of the test groups with 3% carbon source improved by almostly 38% and 48.9%, respectively, compared with pure cement paste. This newly established technique is essential for the future design of excellent graphene-based cement materials and the achievement of multifunctional cementitious applications.
Co-effects of Graphene Oxide and Silica Fume on the Rheological Properties of Cement Paste
Authors: Lu D. , Sheng Z. , Yan B. , Jiang Z. 
Published: July 2023

AbstractPolycarboxylate superplasticizer is typically used to prepare a high-quality graphene oxide (GO) solution before mixing with cement grains. However, even if GO is well dispersed in water, they tend to re-agglomerate in the alkaline cement hydration environment, thus seriously decreasing the workability of the fresh mixture. In this study, we propose a more targeted method by synthesizing GO-coated silica fume (SF) to promote the utilization of GO in cement-based materials. Specifically, the surface of pristine SF was modified to convert their zeta potential (modified SF: MSF), then GO-coated SF (i.e., MSF@GO) was prepared via electrostatic adsorption of GO onto the MSF surface. The experimental results revealed that adding 5MSF@GO hybrid (0.04% GO and 5% MSF, by weight of binder) significantly reduced yield stress and plastic viscosity by 51.5% and 26.2%, respectively, relative to the 0.04% GO-modified sample. These findings indicated that application of GO-coated SF is an effective and environmentally friendly way to develop sustainable cementitious composites.
Automated 3D-Printer Maintenance and Part Removal by Robotic Arms
Authors: Andrews K. , Granland K. , Chen Z. , Tang Y. , Chen C. 
Published: July 2023

Abstract3D printing by means of fused filament fabrication involves extruding and depositing melted material in layers to produce a 3D part. Current 3D printing requires manual intervention from a human operator between prints, leading to inefficiency. The focus of this study was facilitating the automation of the additive manufacturing process. Based on suggestions for future works in this field, this study extended on automated 3D-part removal systems by implementing additional operations to automate the production process. The proposed system uses robotic arms and grippers to operate and maintain 3D printers; specifically, the removal of 3D-printed parts, the cleaning of printer beds, the application of glue to the printer beds to assist with print adhesion, and the monitoring of bed levelness. The importance of this contribution is the improved efficiency of 3D-printing production, allowing for continuous 3D-printer operation and decreasing the requirement for human interaction and monitoring in the production process. The system is demonstrated using a 7 degrees of freedom KUKA robotic arm and ROBOTIQ gripper to autonomously operate and maintain an Ender 3 V2 printer. Sensor data and information from the 3D printers was used to determine the required operation or function to be performed by the robotic system. Tasks were performed by automated movement sequences of the robotic arm and gripper using supplied data. System status was recorded for monitoring and alerting human operators when intervention was required. The implementation of these functions using an automated robotic system allows 3D-printing production to operate continuously for longer periods, increasing production efficiency as downtime and human involvement for maintenance between prints is minimized.
Electrical and Sulfate-Sensing Properties of Alkali-Activated Nanocomposites
Authors: Davoodabadi Maliheh , Liebscher Marco , Sgarzi Massimo , Riemenschneider Leif , Wolf Daniel , Hampel Silke , Cuniberti Gianaurelio , Mechtcherine Viktor 
Published: July 2023

AbstractWe investigated the formation of the conductive network of carbon nanotubes (CNTs) in alkali-activated nanocomposites for sulfate-sensing applications. The matrix was a one-part blend of fly ash and ground granulated blast-furnace slag, activated by sodium silicate and water. Sodium dodecylbenzenesulfonate was used as the surfactant for dispersion of the CNTs in the aqueous media. The nanocomposites were investigated by a laboratory-developed setup to study the electrical and sensing properties of the alkali-activated material. The electrical properties (i.e., conductivity) were calculated and assessed to discover the percolation threshold of the nanocomposites. Furthermore, the sensing behavior of nanocomposites was studied upon sulfate ($${\mathrm{SO}}_{4}^{2-}$$

SO

4

2
-

) exposure by introduction of sulfuric acid ($$({\mathrm{H}}_{2}{\mathrm{SO}}_{4})$$

(

H
2

SO
4

)

) and magnesium sulfate ($${\mathrm{MgSO}}_{4}$$

MgSO
4

). The sensors were able to preliminarily exhibit a signal difference based on the introduced media ($${\mathrm{H}}_{2}{\mathrm{SO}}_{4} \&\mathrm{ Mg}{\mathrm{SO}}_{4}$$

H
2

SO
4

&
Mg

SO
4

), CNT content and $${\mathrm{H}}_{2}{\mathrm{SO}}_{4}$$

H
2

SO
4

volumetric quantity. The results of this research demonstrated a sensing potential of CNT alkali-activated nanocomposites and can be applied in the concrete structural health monitoring.
Investigation on Superhydrophobicity and Piezoresistivity of Self-sensing Cement-Based Sensors Using Silane Surface Treatment
Authors: Dong W. K. , Li W. G. , Lin X. Q. , Shah S. P. 
Published: July 2023

AbstractCement-based sensors are highly susceptible to the effects of watery environments due to the hydrophilic properties of the cement matrix. In this paper, we applied a surface treatment using a silane/isopropanol solution to graphene/cement-based sensors to achieve superhydrophobicity and mitigate piezoresistive instability in watery environments. After treatment, impressive water contact angles of 163.4° and 142.0° were achieved for the surface and inner cement-based sensors, respectively. Moreover, the piezoresistivity of the coated cement-based sensors exhibited greater stability compared to their untreated counterparts. These results provide valuable insights into the piezoresistivity of hydrophobic cement-based sensors in moist environments, offering promising prospects for future structural health monitoring applications.
Roads Issues and the Social License to Operate
Authors: Young W. , Shackleton M. 
Published: July 2023

AbstractBecause it is agreed that the transport system needs the support and engagement of the public in its development and implementation, we explored the concept of the “social license to operate the road system” (SLORS) to show how it can assist in road policy and network implementation. We looked at 18 policy issues and identified their placement in a SLORS framework. The policy issues were categorized into 5 zones: User Advocacy Zone, Support Zone, Equilibrium Zone, Tolerance Zone and Opposition Zone. The relevant zone provides information to policy makers on the public’s view of the policy. For instance: in the Advocacy Zone issues such as Driver behavior should improve, Roads must be safe for all users, the Physical quality of the road and their surface should improve, and Road travel should be more environmentally sustainable in the future are supported—and should be relatively easy to implement. In the Opposition zone People paying a toll or road charge for each trip, Private companies having a large role in planning and management of roads, Increased congestion and Increased traffic on roads in the future receive less support and thus will require considerable effort marketing their implementation. SLORS may assist in pointing the policy maker in the best direction to get the policy supported.
Machine Learning-Aided Nonlinear Dynamic Analysis of Engineering Structures
Authors: Feng Y. , Wang Q. , Wu D. , Gao W. 
Published: July 2023

AbstractA machine learning (ML) technique was used to assist in the dynamic analysis of mixed geometric and material nonlinearities of real-life engineering structures. Various types of inputs of system properties were considered in the 3D dynamic geometric elastoplastic analysis, giving a series of realistic nonlinear descriptions of complex, large deformation structural behaviors. To resolve the numerical challenges of solving the mixed nonlinear problems, a newly established ML technique using a new cluster-based extended support vector regression (X-SVR) algorithm was applied. With this technique, a surrogate model can be built at each time step in the Newmark time integration process, which can then be used to predict the deflection, force and stress of the relevant structural performance at different loading time stages. To demonstrate the accuracy and efficiency of the proposed framework, practical engineering applications with linear and nonlinear properties are fully demonstrated, and the nonlinear behavior of the structure under predicted working conditions in the future was predicted and verified in numerical studies.
Deterioration Modeling of Concrete Bridges and Potential Nanotechnology Application
Authors: Tran H. , Setunge S. 
Published: July 2023

AbstractManagement of aging concrete bridges with limited resources can be a challenge for state authorities. Deterioration modeling of concrete bridges at the component level is essential to optimize maintenance actions and ensure the safety and serviceability of the bridge network. In this study we examined the Level 2 visual inspection data of a concrete bridge’s components collected over 4–5 inspection cycles with the objective of predicting deterioration of components and the bridge’s life cycle. With the increasing application of nanotechnology to increase the mechanical properties and durability of concrete material for bridge structures, the deterioration of nano-based concrete could be significantly different from conventional concrete. A range of deterioration prediction methods, including deterministic models and stochastic models, were examined to understand the validity of the different methods in predicting the deterioration of bridge components made of conventional and nano-based materials. A case study with a demonstration on a concrete open girder was investigated with regard to linear regression models and the stochastic Markov deterioration model. The outcomes can be used to support future study on the performance of conventional and nano-based concrete materials and their lifecycles in the asset management of bridges.
A Novel Concrete Mix Design Methodology
Authors: Kumar D. , Alam M. , Sanjayan J. 
Published: July 2023

AbstractConcrete mix design is the methodology for mixing binder, aggregate and water to achieve required physical, mechanical, and thermal properties. In particular, the physical properties depend on the volume fraction of each element in the concrete recipe. In this study we considered cement mortar, complying with ASTM C105, as the reference concrete with cement as the binder and silica sand as the aggregate. The reference mortar was denser with high thermal conductivity and compressive strength at given rheological properties. A denser concrete presents difficulty in material handling and imposes a safety risk, and high thermal conductivity increases building energy consumption. Therefore, lightweight concrete (LWC) has been developed by replacing silica sand with porous materials. LWC includes cement as the binder, with silica sand and other porous materials as the primary and binary fillers. The mass of the filler materials is determined by their particle density and volume fraction. LWC has low thermal mass, thereby exacerbating the summertime overheating and peak cooling demand of buildings. Therefore, there is a need to design a LWC with high thermal mass by incorporating phase change materials (PCM), which are mainly incorporated as tertiary filler. Here, we propose a novel concrete mix design methodology to incorporate PCM composite as a partial replacement of the porous material without changing binding materials.
Characterization of the Nano- and Microscale Deterioration Mechanism of the Alkali–Silica Reaction in Concrete Using Neutron and X-ray Scattering Techniques: A Review
Authors: Nsiah-Baafi E. , Tapas M. J. , Vessalas K. , Thomas P. , Sirivivatnanon V. 
Published: July 2023

AbstractAlkali–silica reaction (ASR) is one of the most recognized chemical reactions that lead to the deterioration and premature failure of concrete. The severity of ASR is largely dependent on the expansive nature of the reaction product (ASR gel). As such, it is important to expound the developed knowledge on the formation, structure, composition, and swelling mechanism of ASR gel, to provide a greater understanding of ASR deterioration and to facilitate the development of more reliable prediction and mitigation methods. We present a summary of existing methods for assessing ASR and the state-of-the-art techniques that use neutron and X-ray scattering methods to characterize the nano- and microstructural properties of concrete and elucidate the potential transport dynamics of reactants that determine the mechanism and extent of ASR.
Harmonic Vibration of Inclined Porous Nanocomposite Beams
Authors: Chen D. , Zhang L. 
Published: July 2023

AbstractThis work investigated the linear harmonic vibration responses of inclined beams featured by closed-cell porous geometries where the bulk matrix materials were reinforced by graphene platelets as nanofillers. Graded and uniform porosity distributions combined with different nanofiller dispersion patterns were applied in the establishment of the constitutive relations, in order to identify their effects on beam behavior under various harmonic loading conditions. The inclined beam model comprised of multiple layers and its displacement field was constructed using Timoshenko theory. Forced vibration analysis was conducted to predict the time histories of mid-span deflections, considering varying geometrical and material characterizations. The findings may provide insights into the development of advanced inclined nanocomposite structural components under periodic excitations.
Influence of Carbon Nanotubes on the Fracture Surface Characteristics of Cementitious Composites Under the Brazilian Split Test
Authors: Gao Y. , Xiang J. , Yu Z. , Han G. , Jing H. 
Published: July 2023

AbstractTo better analyze the reinforcing mechanisms of carbon nanotubes (CNTs) in cementitious composites, the micromorphological characteristics of the fracture surface of cement-based specimens under the Brazilian split test were investigated. The results demonstrated that the addition of CNTs promoted nucleation and pore filling effects that optimized the pore structure and inhibited the development of microcracks in the cement matrix during loading. Due to the ultra-high specific surface area and bridging effects of CNTs, the formation of hydration products was promoted, internal microcracks and micropores were effectively reduced, and the regularity and integrity of the samples also improved. Therefore, under tensile loading, CNT-reinforced cementitious composites absorbed more energy, resulting in more complex stress paths and rougher fracture surfaces.
Behavior of Hybrid Engineered Cementitious Composites Containing Nanocellulose
Authors: Withana H. , Zhang Y. X. 
Published: July 2023

AbstractNanocellulose (NC) is a promising reinforcing material for cementitious composites, but its effect on the mechanical properties of hybrid engineered cementitious composites (ECCs) has not been studied. In this paper, we investigated a hybrid polyethylene (PE)-steel fibre ECC reinforced with NC and the effect of NC dosages ranging from 0.1% to 0.4% on the compressive strength of the hybrid ECC. The optimum quantity of NC for the best mechanical property of ECC was determined. Enhancement of compressive strength was observed for all the mixes with NC compared with the reference mix, and the mix containing 0.2% NC showed the maximum improvement.
Covariant bit threads
Authors: Headrick Matthew , Hubeny Veronika E. 
Published: July 2023

Abstract
We derive several new reformulations of the Hubeny-Rangamani-Takayanagi covariant holographic entanglement entropy formula. These include: (1) a minimax formula, which involves finding a maximal-area achronal surface on a timelike hypersurface homologous to D(A) (the boundary causal domain of the region A whose entropy we are calculating) and minimizing over the hypersurface; (2) a max V-flow formula, in which we maximize the flux through D(A) of a divergenceless bulk 1-form V subject to an upper bound on its norm that is non-local in time; and (3) a min U-flow formula, in which we minimize the flux over a bulk Cauchy slice of a divergenceless timelike 1-form U subject to a lower bound on its norm that is non-local in space. The two flow formulas define convex programs and are related to each other by Lagrange duality. For each program, the optimal configurations dynamically find the HRT surface and the entanglement wedges of A and its complement. The V-flow formula is the covariant version of the Freedman-Headrick bit thread reformulation of the Ryu-Takayanagi formula. We also introduce a measure-theoretic concept of a “thread distribution”, and explain how Riemannian flows, V-flows, and U-flows can be expressed in terms of thread distributions.
Delaying ACL reconstruction is associated with increased rates of medial meniscal tear
Authors: Erard Julien , Cance Nicolas , Shatrov Jobe , Fournier Gaspard , Gunst Stanislas , Ciolli Gianluca , Porcelli Pasquale , Lustig Sébastien , Servien Elvire 
Published: July 2023

AbstractPurposeThe aim of this study was to evaluate the relationship between the time from injury to ACL reconstruction (ACLR) and the rate as well as repairability of meniscal tears. Secondary aims were to evaluate the relationship between meniscal injury and Tegner Activity Scale, age, BMI, and gender.MethodsBetween 2012 and 2022, 1,840 consecutive ACLRs were performed. A total of 1,317 ACLRs were included with a mean patient age of 31.2 years ± 10.5 [16–60]. Meniscal tear was assessed during arthroscopy using the ISAKOS classification. Time from injury to ACLR, Tegner Activity Scale, age, BMI and gender were analysed in uni‐ and then in multivariate analyses. Patients were divided into four groups according to the time from injury to surgery: < 3 months (427; 32%), 3–6 months (388; 29%), 6–12 months (248; 19%) and > 12 months (254; 19%).ResultsDelaying ACLR > 12 months significantly increased the rate of medial meniscal (MM) injury (OR 1.14; p < 0.001). No correlation was found between a 3‐ or 6‐month time from injury to surgery and MM tear. Performing ACLR > 3, 6, or 12 months after injury did not significantly increase the rate of lateral meniscal (LM) injury. Increasing Tegner activity scale was significantly associated with a lower rate of MM injury (OR 0.90; p = 0.020). An age > 30 years (OR 1.07; p = 0.025) and male gender (OR 1.13; p < 0.0001) was also associated with an increased rate of MM injury. Age > 30 years decreased the rate of MM repair (OR 0.85; p < 0.001). Male gender increased the rate of LM tear (OR 1.10; p = 0.001).ConclusionPerforming ACLR more than 12 months after injury was associated with increased rates of MM injury but not with lower rates of repairable lesions. An increased pre‐injury Tegner activity score was associated with a decreased rate of MM tear. Age > 30 years was associated with an increased rate of MM tear with concomitant ACL injury and a decreased rate of repairability of MM tear. ACLR should be performed within 12 months from injury to prevent from the risk of MM injury.Level of EvidenceLevel III.