Reinforcement Mechanism Research Articles

Dynamic Compaction of High Groundwater Level Subgrade of Buildings: A Model Test-Based Analysis of Stress Distribution and Reinforcement Mechanisms

Dynamic Compaction of High Groundwater Level Subgrade of Buildings: A Model Test-Based Analysis of Stress Distribution and Reinforcement Mechanisms

Phenyl, propyl polysiloxane modified epoxy resin II: The co-continuous phase, concurrently strengthening and toughening mechanism

The applications of epoxy resins are restricted in certain areas due to their brittleness, while improving the epoxy toughness always compromises their strength. We reported a phenyl, propyl polysiloxane modified epoxy resins with excellent tensile strength and toughness before. In this study, the mechanism of strengthening and toughening are studied and elaborated. Compared to cured EP resin (EP), cured P/E resin (P/E20) significantly improved the tensile strength, elongation at break, impact strength, and critical strain energy release rate (GIc) by 45 %, 248 %, 18 %, and 512 %, respectively. Fracture analysis of the P/E20 revealed the appearance of parabolic markings, typical and convincing evidence of ductile fracture, indicating good toughness of the resin. AFM height and Young's modulus plots reveal the complex details of the dimples and the co-continuous phases, which provide the strong evidence to explain the reinforcement and toughening mechanism.

Synergistic reinforcement mechanisms of Cu/graphite composites with MAX phase Ti2AlN and ZrO2-B4C ceramics: Enhancements in mechanical, thermal, and tribological properties

In braking materials field, MAX phase has been introduced into Cu-based composite materials to address issues such as inadequate wetting between ceramic particles and the metal matrix. This study focuses on preparing Ti2AlN-ZrO2-B4C reinforced Cu-based materials via the powder metallurgy method, and investigates the effects and mechanisms of different Ti2AlN/ZrO2 ratios on the mechanical, thermal, and tribological properties of these materials. The addition of an appropriate amount of Ti2AlN (3 wt%) can enhance the densification and mechanical properties of Cu-based materials, as the diffusion of Al atoms promotes the sintering process. Similarly, the diffusion of Al also improves the thermal conductivity at grain boundaries, resulting in samples with higher Ti2AlN content exhibiting superior thermal diffusivity. When the Ti2AlN content reached 7 wt%, the material exhibited optimal hardness (43.35 ± 1.05 HBW), moderate shear strength (19.84 ± 1.86 MPa), as well as excellent high initial braking speed friction coefficient and stability. The reinforcement primarily arises from the diffusion bonding between Ti2AlN and Cu, leading to the formation of Cu-Ti compounds at the interface, which facilitates Ti2AlN in providing frictional force during the friction process and promotes the formation of a friction film due to the “pinning effect”. Additionally, the layered structure of Ti2AlN and the subsequent formation of amorphous Al2O3 after oxidation contributed to the enhancement of friction stability.

Understanding and Mitigating Leadership Fear-Based Behaviors on Employee and Organizational Success

Leadership behavior profoundly influences organizational culture, serving as a cornerstone for environments that foster safety, innovation, and employee satisfaction. This article utilizes research from the primary literature to demonstrate how leaders’ actions and underlying fears influence organizational dynamics and employee outcomes, highlighting the importance of respect, transparency, and trust. Studies have shown that leadership styles shape the work environment, driving innovation and performance. However, concerns over productivity, evaluation, and control can lead to poor communication, low transparency, reduced innovation, and diminished performance, creating a culture of mistrust and anxiety. Authoritarian control or neglect of employees’ needs exacerbates these issues, stifling creativity. The Pygmalion and Golem effects demonstrate how positive reinforcement enhances morale, productivity, and retention, while negative reinforcement is detrimental. Leaders operating under fears of failure or loss of control or political capital inadvertently create a culture of fear and increasingly severe feedback loops of reduced employee trust, satisfaction, and commitment. Addressing these fears fosters open communication, psychological safety, transparency, and mutual respect. Strategies for transforming leadership fears into positive change include promoting open communication, decentralizing decision-making, and implementing positive reinforcement mechanisms. Constructive feedback mechanisms encourage bidirectional communication and help mitigate the negative impacts of leadership fears. Leaders who address their fears can strengthen team trust, enhancing collaboration and engagement. Ultimately, managing leadership fears proactively catalyzes organizational learning and development, promoting a mindset where challenges are seen as opportunities for growth. This approach enhances adaptability and resilience while fostering continuous improvement. Addressing leadership fears and fostering a supportive culture is essential for sustainable productivity and success, serving as a starting point for exploring strategies that support employee performance and development, ultimately contributing to organizational success.

Carbon nanotubes perpendicularly grown on graphene oxide nanosheets derived from metal-organic frameworks: Synergistic reinforcement of poly(l-lactic acid) scaffold

The construction of the nanohybrid composed of two carbonaceous nanomaterials is a promising strategy to inhibit their aggregation, and effectively exert the advantages of their excellent mechanical properties as reinforcement for polymers. Here, carbon nanotubes (CNTs) were in situ perpendicularly growing on the surface of graphene oxide (GO) through metal-organic frameworks (MOF)-derived strategy by chemical vapor deposition (CVD), aiming to facilitate their dispersion on poly(l-lactic acid) (PLLA) bone scaffold fabricated by selective laser sintering (SLS). Specifically, GO provided nucleation sites for the growth of MOF, and worked as the templates when CNTs grew, in which MOF provided catalysts and carbon sources simultaneously. The precursor was heated to 550 °C and kept for 2 h, then heated to 900 °C and kept for 2 h before cooling. The obtained nanohybrid (GO@CNT) exhibited a superior dispersion state than the pure GO in the scaffold at the same loading, especially when the loading was 0.75 wt%. Adding 0.75 wt% GO@CNT endowed the scaffold with a remarkable increment in tensile strength and compressive strength of 13.36 MPa and 24.72 MPa with enhancement of 55.35% and 18.85%, respectively, compared to the scaffold containing 0.75 wt% GO. A crack extension model combined with experiment results was proposed to better understand reinforcement mechanisms. Additionally, the scaffold containing GO@CNT exhibited benign cytocompatibility with a cell-spreading area of 86.31% and cell density of 564 cells/mm2 after culturing for 5 d according to the results of cell adhesion and immunofluorescence tests, making it a promising candidate for bone defect repair.

Enhanced marmatite activation by copper with ammonium sulfate: An experimental and DFT investigation

The presence of iron atoms on the marmatite surface hinders effective interaction between the activator and the mineral, leading to unsatisfactory flotation performance through direct copper (Cu) activation. Hence, this study introduced ammonium sulfate to enhance the marmatite-activation capability by Cu ions. Additionally, the reinforcement mechanism was investigated through microflotation tests, atomic force microscopy (AFM), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and density-functional theory (DFT) calculations. Microflotation results demonstrated that the addition of ammonium sulfate as a complexing reagent increased the flotation recovery of marmatite by 17.36%. AFM analysis revealed that marmatite subjected to enhanced activation (i.e., in the presence of ammonium sulfate) exhibited a considerably higher surface roughness than that subjected to direct Cu activation. Moreover, the average height of hill-shaped materials on the marmatite surface notably increased to 9.6 nm after enhanced Cu activation. SEM-EDS analysis revealed that the concentration of Cu atoms (2.2%) on the marmatite surface after enhanced Cu activation was nearly three times that (0.8%) after direct Cu activation. Additionally, XPS results indicated a considerably higher presence of the Cu–S component on the marmatite surface after enhanced Cu activation than after direct Cu activation. ToF-SIMS analysis indicated an increase in the fragment peaks of Cu+, CuOCS2+, OCS2−, and OC2H2S2− on the surface of enhanced-activated marmatite. Additionally, DFT calculations indicated that the presence of NH3 molecules enhanced electron transfer between Cu and S on the hydrated marmatite surface. The marmatite (1 1 0) surface exhibited more negative adsorption energy of Cu ions after the action of NH3 molecules, and NH3–Cu showed a more stable adsorption configuration than Cu. Therefore, the addition of ammonium sulfate enhanced the Cu activation for marmatite, thereby improving flotation performance.

Experimental study on bending fatigue performance of ambient-cured ultra-high-performance concrete thin plate with embedded steel wire mesh

Ambient-cured ultra-high-performance concrete (ACUHPC) with embedded steel wire mesh (SWM) was studied experimentally. ACUHPC-SWM thin plates having different SWM wire ratios and fatigue load stress levels were tested to clarify the effects of SWM on static and fatigue bending behavior. Subsequently, the fatigue equations for ACUHPC-SWM materials (with different failure probabilities) and reinforcement efficiency of the SWM were proposed. Finally, the reinforcement mechanism of the SWM was revealed by comparing it with ACUHPC thin plates. The results show that the inclusion of wire mesh significantly improved the cracking strength, ultimate static strength, energy dissipation performance, and fatigue ultimate strength of ACUHPC, with maximum increases of 23.63 %, 260.32 %, 940.42 %, and 196.34 %, respectively. As the wire mesh ratio increased, the improvement in fatigue ultimate strength initially increased and then decreased once the wire mesh ratio exceeded 1.884 %. The mechanism according to which SWM enhances ACUHPC involves the action of the mesh as a bridge to delay crack development and increase toughness.

A finite element analysis method for random fiber-aggregate 3D mesoscale concrete based on the crack bridging law

Mesoscale modeling is an emerging analytical method that can be used to study fiber-reinforced concrete. However, fine fibers with micrometer diameters are distributed in millions in a standard specimen, so it is impossible to establish a mesoscale model and further analyze it, which severely limits the investigation of the reinforcement mechanism of fine fibers on concrete. This paper efficiently established a highly applicable mesoscale analytical model for random fiber-polyhedral aggregate concrete in Abaqus software based on a comprehensive examination of the crack bridging law and the supplementation of the fiber spacing theory, combined with the improvement of the algorithms of aggregate generation, fiber arrangement, and the judgment of the fiber-aggregate contact by the secondary development method of Python, as well as the matrix-dual arrangement method. Additionally, basalt fiber concrete and mortar specimens were prepared and tested, and the parameters of the model were calibrated to verify the model's authenticity. The result shows that the method proposed in this paper can accurately and efficiently perform mesoscale concrete analysis with fine fibers. In the peak load stage, the fiber has the strongest alleviation effect (Δ = 0.033) on the matrix damage, 10 times that of the crack initiation stage (Δ = 0.003). With the development of damage, fiber stress increases gradually from the crack initiation stage (0.68 σfu), and the growth rate (41.53 %) is the largest at the peak load stage (σfu), which reveals the complex dynamic bridging effect of fiber on the matrix. This investigation proposes a novel and broad applicability methodology for the finite element analysis of fiber-reinforced aggregate mesoscale concrete.

Improving erosion resistance of calcareous sand slope with zinc sulfate solution

Loose and uncemented calcareous sand slopes are prone to collapse under rainstorm erosion. In order to improve the erosion resistance stability of slopes, it is crucial to enhance the erosion resistance of calcareous sand. In this study, a new method of cementing calcareous sand with zinc sulfate solution (ZSS) is proposed. The ZSS reinforcement technique can effectively cement calcareous sand, enhance the mechanical properties and help reduce erosion on calcareous sand slopes. A series of laboratory experiments were conducted, including uniaxial compression tests, Brazilian splitting tests, surface penetration tests, microscopic tests, and rainfall scouring tests. The test results show that the uniaxial compressive strength of calcareous sand achieved 8.3 MPa reinforced with ZSS. Microscopic analyses revealed the mechanism of reinforcement, discovering the formation of environmentally friendly compounds such as ZnCO3 and CaSO4·2 H2O between calcareous sand particles, which enhanced the soil mechanical properties. The calcareous sand slope reinforced with ZSS forms a hard shell on the slope surface, which effectively improves the erosion resistance of the slope. After being reinforced with a ZSS concentration of 1.0 mol/L, the slope remained stable after 20 min of scouring at a rainfall intensity of 80 mm/h. This method provides a quick solution for reinforcing calcareous sand slopes and holds promising potential for practical engineering applications.

Single overall ‘H-shaped’ multifunctional compound achieves fire safety, durability, enhanced strength, and smoke suppression of cotton fabrics

Challenges currently faced by phosphorus-based flame retardants for cotton fabrics include reduced fabric strength after treatment, high smoke release during combustion, formaldehyde release from commercial phosphorus-based flame retardants and poor flame retardant durability after treatment. In the present work, a P/N/B synergistic flame retardant TBST is synthesized using phosphoric acid, cyanuric acid, boric acid, pentaerythritol, etc. The phosphorus‑nitrogen‑boron atomic ratio is 2:3:1, and it is successfully prepared on cotton fabric to prepare TBST/Cotton. When the weight gain rate is 29.8 %, the LOI value is 41.6 ± 0.3 %, indicating that TBST/Cotton has excellent flame retardant performance. At the same time, in the vertical flame test, the length of residual carbon is 5.6 cm. In addition, the THR and HRR are reduced by 58.4 % and 91.9 % respectively compared to Cotton, indicating that TBST/Cotton has excellent combustion performance. In addition, compared to the residual carbon content of Cotton at 710 °C, the residual carbon content of TBST/Cotton in nitrogen increased by 27.79 %. For a 30 % increase in weight, the increase in longitudinal mechanical strength is 23.1 %. Inferred the decomposition mechanism and flame retardant mechanism of TBST/Cotton. TBST/Cotton has the advantages of good flame retardant durability and enhanced mechanical properties, and the reinforcement mechanism of TBST has been speculated.

Preparation of high-strength and low-shrinkage composite salt cores by binder jetting and vacuum impregnation

ABSTRACT Binder jetting (BJ) technology was employed combined with vacuum impregnation to fabricate alumina-reinforced Na2SO4-NaCl water soluble composite salt cores (WSCSC), intended for manufacturing aluminum alloy castings featuring intricate cavity structures. The bending strength and sintering shrinkage rate of WSCSC were investigated to discern the influences of alumina content, vacuum impregnation pressure and time, accompanied by a detailed analysis of the microstructure and reinforcement mechanism. The findings reveal that WSCSC containing 40 wt.% alumina exhibits exceptional mechanical properties, demonstrating a bending strength of 29.13 MPa, which is 197% higher than that of WSCSC without alumina. Furthermore, when the vacuum impregnation of saturated brine is conducted at a pressure of 30 KPa for 90 s, the resulting WSCSC possesses a sintering shrinkage rate of 4.94%, reflecting a significant reduction of 73.5% compared to that of WSCSC without vacuum impregnation treatment. Microstructural analyses show that alumina, as a stable secondary phase, can refine the NaCl grains within WSCSC, deflecting cracks and elongating their propagation paths, thereby remarkably enhancing the bending strength. Moreover, the fine inorganic salt particles crystallized and precipitated from saturated brine during the drying process are filled in the internal pores of WSCSC through vacuum impregnation, dramatically reducing the sintering shrinkage rate. Ultimately, the high-strength and low-shrinkage WSCSC parts were successfully manufactured.

Study of Interlaminar Fracture Toughness and Flexural Properties of Carbon Fibre Composites Reinforced with Polyethersulfone/Graphene Oxide Films

Unidirectional carbon fibre reinforced plastic (CFRP) composites were prepared by inserting polyethersulfone (PES) films or polyethersulfone/graphene oxide (GO) films into the composites and used to improve the interlaminar fracture toughness as well as the flexural properties. The effect of low-temperature cycling (35, 70, 105, and 140 cycles between −55 °C and room temperature (25 °C)) on the flexural properties of the specimens was also investigated, and the damage caused to the reinforcement layer was directly detected by comparing the interlaminar images. The results of the double cantilever beam (DCB) test and the end notched flexure (ENF) test were used to verify the optimisation of the interlaminar fracture toughness and flexural properties of the new composite film (PES/GO film). The results show that the performance of PES/GO film under both DCB test and ENF test is superior to that of PES film. Regarding the effect of low-temperature cycling on the specimens, the flexural properties of the specimens containing PES/GO films were improved. Finally, the matrix interface and failure mechanism of the interlayer reinforcement were investigated by scanning electron microscopy (SEM).

Dodging reality, striking the virtual: An undulating strategy for effectively enhancing CF/PEEK interfacial adhesion!

The design of carbon fiber (CF)-reinforced polyetheretherketone (PEEK) composite materials with suitable interfaces has consistently been challenging. In this study, we sulfonated poly (phthalazinone ether sulfone ketone) (PPESK) and PEEK to prepare water-soluble SPPESK and SPEEK. Subsequently, we prepared a water-soluble sizing agent (SPPESK/SPEEK) via a straightforward blending process. This sizing agent tended to accumulate randomly on the surfaces of CFs, forming a thin film with a heterogeneous structure in the nanoscale. At the molding temperature of the composite material, the two components on the fiber surface exhibited different rheological behaviors, with PEEK preferentially infiltrating the SPEEK region, forming strong molecular entanglements. Meanwhile, the SPPESK region provided a rigid supportive structure, offering the potential for the mechanical interlocking of PEEK in the interface layer. The performance of the prepared composite materials was significantly enhanced, with their interlaminar shear strength and flexural strength reaching 87.1 MPa and 975.8 MPa, respectively. With respect to those of commercial fiber-reinforced PEEK composites, an 89.8 % increase in interlaminar shear strength and a 79.39 % increase in flexural strength were observed. This interface reinforcement mechanism presents a universally applicable strategy for the future development of fiber-reinforced composite materials.

Molecular Dynamics Analysis of Surface-Modified Carbon Nanoparticle Reinforced Epoxy Resin.

Surface-modified carbon nanoparticles (CNPs) as reinforcement materials have attracted significant attention due to their potential for substantially enhancing mechanical properties. However, the development and application of CNP-enhanced polymeric materials are constrained by an incomplete understanding of their reinforcement mechanisms, impeding sustainable progress. In this study, we employed molecular dynamics simulations to investigate the mechanical properties of surface-modified CNP-reinforced epoxy resin composites at the microscopic scale. The simulations focused on the tensile process and the nanopinning effect of CNPs within the epoxy resin matrix. Our results indicate that surface-modified CNPs form stronger interfacial connections with the epoxy resin, leading to enhanced mechanical strength of the composites. Quantitative analysis revealed that these composites exhibit higher tensile strength compared to nonmodified counterparts, with a significant improvement in stability due to the robust noncovalent interactions between CNPs and the epoxy matrix. This study elucidates the reinforcement mechanisms of surface-modified CNPs in polymers, providing valuable insights for further optimization and sustainable development of CNP-reinforced polymeric materials.

Strength test and reinforcement mechanism of gangue-building solid waste-based cement filling material improved by soda residue

To utilize solid soda residue (SR) and building solid waste (BSW), this study proposes to use SR for modification and preparation of mining-used soda residue-gangue-building solid waste-based cement filling material (SGBCFM). In this study, we studied the influence of fly ash (FA) content, SR content, BSW content, and mass concentration (MC) on the early strength and later strength of SGBCFM. Through XRD and SEM tests, we analyzed the hydration products and microstructure of SGBCFM and investigated the mechanism of SR enhancing the later strength of SGBCFM. The results show that these influencing factors have a weaker impact on the early strength of SGBCFM, but a significant impact on later strength. These influencing factors can be ranked from the most significant impact to the least impact as follows: MC, SR content, FA content, and BSW content. A proper amount of SR can effectively improve the later strength of the material, but an excessive amount of SR leads to a decrease in strength; SR has combined effects such as micro-aggregate filling, alkali activation, and promoting cementation reactions. These effects can increase the original cementitious substances and generate new compounds, effectively enhancing the later strength of SGBCFM.

Parameters affecting performance of fully instrumented model testing of strip footings on geocell-reinforced soils

A thorough study was conducted to assess the performance of the strip footing reinforced with geocells in sand, focusing on understanding the enhancement effects and geocell reinforcement mechanisms. Critical factors such as geocell modulus, height, soil relative density and load eccentricity were examined through fully instrumented model tests. Measurements included surface displacement profiles, strains on the geocell layer, subsurface pressure distribution and other relevant parameters. Results revealed that the strip footing on geocell-reinforced sand beds exhibited better performance compared to those on unreinforced soil, characterized by increased load-carrying capacity and reduced settlements. Notably, stiffer geocells improved performance significantly, with a 40% higher modulus enhancing the bearing pressure by up to 25%, due to better confinement and anchorage effects. Conversely, geocells with a lower modulus demonstrated more effective vertical stress distribution. Furthermore, increased geocell height moderately enhanced footing performance by improving confinement, although wall buckling under eccentric loading limited major gains. Dense soils under centric loading exhibited up to a 20% better improvement in bearing pressure than loose soils due to higher strain mobilization within the geocell layer. These findings highlight the crucial role of geocell and soil properties, as well as loading conditions, in optimizing reinforcement effects for strip footings.

Exploring the reinforcing mechanism of graphene oxide in cementitious materials through microstructural analysis of synthesised calcium silicate hydrate

Graphene oxide (GO) has been shown to enhance the mechanical properties and durability of cementitious materials, although the exact reinforcement mechanism is not fully understood. Given the critical role of calcium silicate hydrate (CSH) in determining these materials' properties, this study investigates the microstructural changes in CSH with the incorporation of GO. Using a co-precipitation method, CSH samples with and without GO were synthesised and characterised through thermogravimetric analysis (TGA), X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and nuclear magnetic resonance (29Si NMR and 1H NMR). The results demonstrated that GO incorporation enhances the polymerisation and crystallinity of CSH, as evidenced by TGA and XRD. FTIR and SEM analyses indicated that the CSH structures became more ordered and denser with GO addition. NMR analysis further confirmed improved structural order and reduced interlayer spacing. Overall, incorporating GO into CSH significantly increases crystallite size and promotes a more ordered CSH structure. These effects collectively result in enhanced load transfer, improved crystal interlocking, and a synergistic improvement in the mechanical properties and durability of cementitious materials.

Bioprinting with superelastic and fatigue-resistant bioinks for large-sized tissue delivery

3D bioprinting technology is advancing rapidly to construct multi-scale preformed architectures that satisfy the demands of tissue regeneration. However, challenges remain in accurately delivering large-sized preformed architectures to the defect sites without being damaged by the mechanical environment in vivo. In this study, we proposed a versatile bioprinting strategy to fabricate large-sized architectures with remarkable injection capacity for geometry-independent minimally invasive tissue delivery. We design a novel hydrogel by mixing gelatin methacryloyl with poly(ethylene glycol) diacrylate (PEGDA) and photocrosslinking the mixture under a white light source. The hydrogel forms a reinforced crosslinking network, exhibiting superelasticity and fatigue resistance. We infer that the flexible chains of high-molecular-weight PEGDA and interconnected macropores of hydrogel contribute to the reinforcement mechanisms. With a decoupled bioprinting strategy, the bioink can be 3D printed into large-sized architectures with different geometries and tunable Poisson’s ratio. The printing architectures displayed excellent deformation and shape recovery capacity by compressing to less than 1% of the original size and fully recovering after injection. The injection capacity is geometry-independent, indicating the intrinsic properties of the hydrogel and allowing higher freedom for the structural design and geometry size of the architectures. The bioprinting process is compatible with genome-edited hepatic cells with high cell-bioprinting suitability, demonstrating high cell viability, a minimally altered transcriptomic profile after bioprinting, and a biocompatible microenvironment that supports cell survival and hepatic function maintenance. The cell-laden architectures express uncompromised injection capacity with unaffected cell viability after injection. This study presents a generalizable strategy for preparing and bioprinting with superelastic and fatigue-resistant bioinks into customized cell-laden architectures to facilitate minimally invasive large-sized tissue delivery.

Study on short fiber reinforcement mechanism for mechanical performance improvement of 3D‐printed short‐continuous carbon fiber reinforced thermoplastic composites

Study on short fiber reinforcement mechanism for mechanical performance improvement of <scp>3D</scp>‐printed short‐continuous carbon fiber reinforced thermoplastic composites

AlN reinforced Fe activated sintered tungsten matrix composites: Mechanical properties, fracture behaviors and reinforcement mechanisms

In this study, AlN particles were proposed as the reinforcement to prepare Fe activated sintered tungsten matrix composites. The results indicated that the AlN particles stably existed inside the W(Fe) matrix and exhibited a significant strengthening and toughening effect. Compared with the W(Fe) material, the maximum microhardness, flexural strength and fracture toughness of the composites were increased by 101.42%, 66.29% and 64.63%, respectively. An AlN content-AlN particle size-composite fracture mode map was constructed to classify the four fracture modes of the composites. In addition to the fine grain strengthening and residual stress strengthening, a novel “oxygen purification strengthening effect” was found, which resulted from the thin (Fe,Al)2O3 reaction layer formed at the AlN/W(Fe) matrix interface.