Interfacial Strength Research Articles

Stabilizing Metal Coating on Flexible Devices by Ultrathin Protein Nanofilms.

The significant modulus difference between a metal coating and a polymer substrate leads to interface mismatches, seriously affecting the stability of flexible devices. Therefore, enhancing the adhesion stability of a metal layer on an inert polymer substrate to prevent delamination becomes a key challenge. Herein, an ultrathin protein nanofilm (UPN), synthesized by disulfide-bond-reducing protein aggregation, is proposed as a strong adhesive layer to enhance adhesion between polymer substrate and metal coating. Unlike traditional biopolymer adhesives with micrometer-scale thicknesses, the UPN layer is minimized to nanometer/single-molecular scale. Such UPN thereby effectively enhances the interfacial adhesive strength and reduces the cohesion contribution in the entire adhesion system by directly connecting two interfaces with a nearly single-molecular thickness. Using UPN as the adhesive layer, a multifunctional metal coating could be reliably adhered on flexible polymer substrates by ion sputtering, delivering unprecedented adhesion stability even under repetitive mechanical deformation. Applications of this design include reversible transparency control, tension-responsive encryption, reusable optical sensing, and wearable capacitive touch sensors. This work highlights UPN's potential to create strong bonding strength between flexible polymers and metal coatings, offering a biocompatible solution with high surface activity and low cohesion, facilitating the development of hybrid devices with stable metal nano-coating.

Interfacial adhesion enhancement in high‐modulus carbon fiber/poly (ether ether ketone) composites: through the flexible macromolecule‐grafted‐carbon nanotubes sizing treatment

AbstractIn this study, a flexible macromolecule‐grafted‐carbon nanotube (t‐CTN‐SPEEK) is developed and utilized as bridge to enhance the interfacial properties of high‐modulus carbon fiber (HM‐CF) reinforced poly (ether ether ketone) (PEEK) composites. With t‐CTN‐SPEEK sizing, the wettability of HM‐CF is enhanced, thereby promoting better resin wetting. The increased roughness induced by the t‐CTNs‐SPEEK on the surface of the HM‐CF affords improved mechanical interlocking among interface. Additionally, SPEEK enhances the interfacial compatibility of the composites. Thus, after the t‐CTN‐SPEEK sizing treatment, the composite exhibits the best interfacial shear strength (IFSS), as evaluated using the interfacial strength evaluation instrument. This paper also discusses in detail the interfacial strengthening mechanism after sizing and presents a promising approach to enhancing the interfacial properties of HM‐CF composites.

Asymmetric Proton-Exchange-Enhanced Lithium Niobate and Silicon Low-Temperature Direct Bonding with an Ultrathin Heterogeneous Interface.

The integration of lithium niobate (LiNbO3 or LN) and silicon (Si) has emerged as a promising heterogeneous platform for microelectromechanical systems (MEMSs) and photonic integrated circuits (PICs). Particularly, the lithium niobate on silicon (LNOS) architecture leverages the superior piezo-optomechanical properties of LN, making it compatible with superconducting circuits and quantum systems. This opens an avenue for the development of advanced quantum sensors and processors. However, existing LN and Si bonding methods suffer from inherent limitations, such as low interfacial strength and the formation of thick, amorphous interlayers. In this work, we present an asymmetric surface activation strategy to address these challenges. By employing proton-exchange-enhanced chemical activation on the LN surface and oxygen plasma treatment on the Si side, we have achieved remarkable bonding strengths of up to 10 MPa at a moderate annealing temperature of 150 °C. Notably, the bonding mechanism in our approach differs from that in conventional diffusion-based processes. Here, the dehydration condensation of surface functional groups results in an exceptionally thin interfacial layer, less than 2 nm thick, without the presence of amorphous LN. This innovative fabrication method for LNOS demonstrates superior reliability, piezoelectric performance, thermal management capabilities, and optical transmission qualities, paving the way for cutting-edge photonic and quantum applications.

Effect of Particle Shape on Cyclic Shear Behavior of Granular Mixtures–Geogrid Interface

The cyclic shear stiffness and damping ratio of angular and round particle geogrid interfaces is of much concern in reinforcement structure seismic analysis. In this study, various component percentages of crushed limestone and spherical granular medium mixtures were used to investigate the role of particle regularity in static and cyclic direct shear tests. The test results revealed that an increase in the proportion of round particles decreased cyclic shear strength and volume change. The phenomenon of shear softening was observed with a high amplitude of shear displacement when the proportion of round particles was increased in the mixture. As the percentage of round particles increased, the maximum interface shear stiffness decreased significantly from, 39.69 to 28.28 MPa/m, but a reverse trend in the maximum damping ratio was observed, from 0.308 to 0.37. The effect of cyclic shear history and proportion of round particles on interface strength parameters was also analyzed. A linear regression model was fitted to the data for quantifying the relationship between the proportion of round particles and friction angle. The results suggest that different percentages of round and angular particles can produce varying degrees of particle interlock between aggregate and geogrid, influencing the macro-mechanical behavior of the reinforced soil interface.

Exploring the multi-scale evolution mechanism of the ultra-high-temperature mechanical behaviour of carbon/carbon composites

The microstructure and mechanical properties of Carbon/Carbon (C/C) composites were investigated after ultra-high-temperature heat treatment (HTT) in the range of 30 – 2950 °C. The evolutionary mechanisms of the mechanical behaviour were explained at three scales: graphene sheets, carbon fibre (CF) monofilaments and the C/C composites. The results displayed that the tensile strength of CF monofilaments decreases monotonically as the HTT increases, while C/C composites present a tendency to decrease and then increase, demonstrating that CF/matrix interfacial properties play a decisive role in the tensile properties. Obvious microstructure change of C/C composites after HTT at 2700 °C was observed, meanwhile the high temperature tensile strength (measured at 2000 °C and 2500 °C) for the composites treated at temperature beyond 2600 °C was higher than that of room temperature. The high-temperature mechanical properties of C/C composites were regulated by the competing mechanisms of the graphite crystallite structure and the skin-core structure of CF monofilament, the CF/matrix interfacial strength and the porosity of C/C composites.

Strength gradient in impact-induced metallic bonding

Solid-state bonding can form when metallic microparticles impact metallic substrates at supersonic velocities. While the conditions necessary for impact-induced metallic bonding are relatively well understood, the properties emerging at the bonded interfaces remain elusive. Here, we use in situ microparticle impact experiments followed by site-specific micromechanical measurements to study the interfacial strength across bonded interfaces. We reveal a gradient of bond strength starting with a weak bonding near the impact center, followed by a rapid twofold rise to a peak strength significantly higher than the yield strength of the bulk material, and eventually, a plateau covering a large portion of the interface towards the periphery. We show that the form of the native oxide at the bonded interface—whether layers, particles, or debris—dictates the level of bond strength. We formulate a predictive framework for impact-induced bond strength based on the evolution of the contact pressure and surface exposure.

Study on Low-Temperature Deposition of Diamond-like Carbon Film on the Surface of Bionic Joint Thread and Its Properties

The double-connection structure of bionic joints of mining drill pipes has solved the problem of drill drop caused by fatigue cracks. However, with low-melting-point elastic–ductile alloy filling in the bionic joint, the thread on the joint cannot be hardened by high-temperature surface hardening treatments such as quenching and nitriding, making it prone to thread gluing or excessive wear. In this paper, the feasibility of diamond-like film deposition on the surface of a bionic drill pipe thread was studied. A tungsten transition film was used to improve the thickness of the film and the interfacial bond strength between the film and the substrate. The test results show that the total thickness of the DLC film is about 3~5 μm, the roughness is less than 2 μm, the hardness of the film reaches 24.4 GPa, the friction coefficient is 0.04, and the critical load is 56 N. SEM and EDS analyses show that the tungsten film and the bionic joint thread form a metallurgical structure. The morphology of the diamond-like carbon film is uniform and dense, and there is no obvious stratification between the substrate material. The joint with a diamond-like coating treatment has a longer service life than joints receiving conventional high-temperature nitriding treatment.

Three-dimensional cohesive finite element simulations coupled with machine learning to predict mechanical properties of polymer-bonded explosives

Developing multifactorial predictive models for the design of polymer-bonded explosives (PBXs) is of importance for their further application in insensitive munition fields. As a popular method, finite element simulations can provide a reliable prediction, but are laborious and expensive if considering the extensive design parameter space. In light of this challenge, we proposed a coupled strategy that includes machine learning (ML) and three-dimensional cohesive finite element simulation for effciently predicting the mechanical properties of PBXs. The strain rate, particle volume fraction, interface strength, fracture energy, and the binders are considered as the main factors of tailoring the tensile strength of PBXs. To improve the prediction performance, an augmented database of 2500 data sets utilizing GANs neural network were established and then processed to train and test six ML models. The results show the accuracy and generalizability of the low-computational-cost ML models in predicting the mechanical properties of PBX composites. The predicted values from these models are in good agreement with the experimental ones. Feature contribution analysis demonstrates that the tensile modulus and failure strain are most affected by the binders, while the tensile strength are most affected by the fracture energy. Using the above conclusions as design guidelines, we can develop the new PBX formulations according to different mechanical property requirements for their optimal use across insensitive ammunitions. This strategy can be a viable machine-learning-assisted solution to designing PBXs.

Analysis of serum phase proteins and emulsifiers on the whipping capabilities of aerated emulsions: From the perspective of air-liquid interface rheology

In aerated emulsions, the serum phase plays a crucial role in determining whipping capabilities. However, the effects of serum phase components on emulsion properties remain largely unexplored and continue to be a mystery. This study takes a micro-level approach, focusing on the air-liquid interfacial rheology by incorporating different types of surfactants (proteins and emulsifiers) into the serum phase. It systematically explores the effects on the serum phase interface, emulsion properties, whipping capabilities, and foam stability in a stepwise manner. Proteins only slightly affect the strength of the air-liquid interface, primarily improving the capacity to trap bubbles at the initial whipping stage, thereby boosting the overrun of the aerated emulsion. The high viscoelastic modulus of the interface membrane is greatly influenced by the presence of solid lipid nanoparticles of glycerol monostearate (GMS SLN), leading to a reduction in whipping time and improved surface-mediated partial coalescence. This ultimately enhances the quality and stability of the foam system. Tween 80, due to its hydrophilic properties, is able to quickly adsorb at the air-liquid interface using the Gibbs-Marangoni mechanism. This helps to expedite the end of the whipping process and ultimately improves the foam quality. On the contrary, glycerol monooleate (GMO), a lipophilic emulsifier for liquids, struggles to effectively adsorb at the interface, leading to decreased stability of the air-liquid interface in the system and resulting in poor whipping capabilities. This paper delves into the mechanism by which different surfactants affect the whipping capabilities of aerated emulsions through an analysis of serum phase composition, laying the groundwork for enhancing formulation design.

The synergistic effect of nano-Al2O3 size and concentration on the interfacial adhesion properties of SMA/PDMS composites and their enhancement mechanism

Soft actuators composed of shape memory alloy (SMA) wires embedded in polydimethylsiloxane (PDMS) matrix hold potential for shape-morphing structures and soft robots. However, SMA exhibits poor bonding with PDMS due to its smooth and nonpolar surfaces. Nanoparticles show promise in interfacial strengthening of polymer composites. In this work, KH590 was used to modify nano-Al2O3 particles and deposited on the SMA surface, creating a three-dimensional nanostructure bridging SMA and PDMS to enhance interface strength. The synergistic effects of particle size and content of nano-Al2O3 particles on the interface strength were investigated in detail. It founds that interfacial strength decreased exponentially with particle size at content of 1 wt%, while when the content exceeds 1 wt%, the interface strength firstly increases with the particle size and then decreases in a logarithmic trend. Specifically, the interface strength is enhanced by 110 % with 3 wt% 50 nm particles. The interface enhancement mechanism was also discussed. The proposed nanoparticle modification approach was to strengthen SMA/PDMS interphase by increasing and extending fracture path, consuming more fracture energy. Chemical cross-linking also contributed to interface enhancement. This work enhances understanding of interfacial bonding mechanisms and provides valuable guide for interfacial strengthening of SMA/PDMS.

Plastic strain localization in Bouligand structures

The Bouligand structure represents helicoidal stacking of aligned fibers; such a structure is widely observed in biological composites. Despite the progress in characterization of toughening caused by Bouligand arrangement of fibers, the inelastic deformation mechanisms of this structure remain elusive. In this study, we carry out calculations for plastic deformation of Bouligand structure, crossed-lamellar structure and the single lamellar structure. It is found that the single lamellar structure and crossed-lamellar structure can undergo necking, while in the Bouligand structure, plastic strain localization bands develop, which is accompanied by plastic rotating of fibers, lamellar twisting and lamellar delamination. Compared with crossed-lamellar structure, the Bouligand structure exhibits lower plastic energy dissipation. However, the Bouligand pattern can activate delamination of lamellae, generating high level of damage energy dissipation. The plastic deformation of Bouligand structure depends on the fracture properties of interface between adjacent lamellae. It is identified that the plastic dissipation of Bouligand structure increases with increasing cohesive strength of lamellar interface, and dominant shear bands emerge in the case of weak lamellar interface. The high strength of lamellar interface plays a role in promoting twisting of lamellae. We have further revealed the effect of the thickness of individual lamella on plastic deformation of the Bouligand structure. The thick lamella is capable of suppressing plastic strain localization in Bouligand structure, thereby giving rise to high plastic dissipation. The findings of this study shed new light on the development of bioinspired Bouligand-type materials.

Deep learning assisted prediction on main factors influencing shear strength of sintered nano Ag-Al joints under high temperature aging

Bonding strength of sintered nano silver (Ag) joints has been an important index for evaluating the reliability of power module packages, which has been reported to be influenced by many factors. However, it is hard to evaluate and predict those factors affecting bonding strength. With the help of artificial intelligence (AI), the utilization of AI tools to assist in finding science solutions has become a mainstream consensus. In this paper, we will show how to evaluate and predict those sintered nano Ag-Al bonded joints bonding strength with deep learning (DL) methods. Firstly, a reliable extended dataset was obtained using the conditional formal condition table generation Induction Network (CTGAN) based on the die shear test dataset of sintered Ag-Al interface shear strength with four different metallization layers under different high-temperature aging time. Subsequently, four DL models were adopted to predict the shear strength of Ag-Al interface under different metallization layers to evaluate the interface bonding strength, all with high level of determination coefficient (R2, above 0.99) and classification accuracy (above 85%). Last but not least, factors influencing the shear strength of Ag-Al interface were analyzed and ranked by weight analysis and SHapley Additive exPlanations (SHAP) method. This research could provide a novel perspective on understanding those factors affecting the shear strength of sintered nano Ag interconnect layer in power devices.

Influence of elevated temperature on the interfacial adhesion properties of cement composites reinforced with recycled coconut fiber

Magnesium phosphate cement (MPC) is the preferred material for rapid repair due to its rapid setting and early strength properties. However, its inherent brittleness renders it less suitable for use in assembled building nodes. To address the brittleness of MPC, coconut fiber (CF), a natural fiber known for its toughness, is often employed as a reinforcement. However, CF-MPC encounter difficulties in high-temperature settings, such as fire emergencies, which may compromise the interfacial bonding properties of this materials. This paper presents an investigation into the interfacial bonding properties of CF-MPC at elevated temperatures. The study employed microscopic analysis to observe the material changes of CF at elevated temperatures, evaluated the mechanical property changes by means of Fiber Tensile Test, and assessed the interfacial bonding performance by means of Fiber Drawing Test between CF and MPC. The findings indicated that as the temperature increased, the carbonized residue of the CF gradually decomposed, resulting in a notable decline in mechanical strength. Upon exceeding 400°C, the carbonization of CF was complete, resulting in the loss of its mechanical properties. Besides the results also demonstrated that the interfacial bond strength of CF-MPC at a burial depth of 7.5 mm reaches its maximum value of 2.14 MPa at 20°C. As the temperature rises to 200°C, the interfacial bond strength at a burial depth of 12.5 mm reaches its maximum value of 1.08 MPa at this temperature. The findings of this study are conducive to promoting the application of CF-MPC at high temperatures and provide a theoretical basis for the subsequent optimization of this material.

Microdroplet Pull-out Testing: Significance of Fiber Fracture Results

Fiber reinforced composites are used in structural materials that required light weight and stiffness. The properties of the fibers or matrix are important, but the interfacial properties have a significant impact on the properties of fiber reinforced composite. In this study, the interfacial shear strength (IFSS) was measured using acrylic resin and epoxy resin as base materials. The chemical composition of acrylic and epoxy matrix materials was analyzed to predict the effects on IFSS. Additionally, IFSS was measured through a microdroplet pull-out test. The reliability of the experimental results was enhanced by applying a statistical analysis to IFSS results. In the case of epoxy, GF/epoxy exhibited higher IFSS to twice and half times than CF/epoxy specimens. It means that the surface treatment of the fibers has a significant impact on the interface. In the case of acrylic, IFSS could be measured for GF. But in the case of CF, IFSS was too low to get accurate results of IFSS. Through this research, methods to improve the accuracy of composite interfacial strength measurement experiments were examined, and the study suggested the need for standardized criteria to evaluate composite interfacial adhesion.

Enhanced interfacial joining strength of joined high chromium gray cast iron/low carbon steel joint via graphite coating

Liquid-state bonding is one of the most crucial methods in joining dissimilar materials to manufacture composites with structural design. The high chromium gray cast iron (HCGCI)/low carbon steel (LCS) composite structure is attractive in mining industries due to its superior mechanical properties and low density. However, the decarburization of the faying surface of HCGCI leads to the formation of a coarse-grained brittle interlayer between HCGCI and LCS which seriously deteriorates the mechanical properties of welded joints. In this work, high chromium gray cast iron/low carbon steel composite was fabricated by diffusion bonding via graphite coating layer. The results showed that the graphite coating on the fusion surfaces prevented the decarburization of HCGCI and the growth of coarse grains which improved the bonding quality. The ultimate tensile strength and total elongation of the graphite-free sample are 335.6 MPa and 8.9%, respectively. In contrast, the ultimate tensile strength and total elongation of the graphite-contain sample are 435.6 MPa and 17.9%, separately. This work opens a new strategy for fabricating high chromium gray cast iron/low carbon steel composite, and the flexibility to achieve complex structures through liquid-state bonding is extended.

A simple two-step reaction for synthesizing demulsifiers for a high salt crude oil emulsion

In this paper, two demulsifiers (PDA-L and GDA-L) were synthesized by grafting lauric acid on polyethylene glycol diglycidyl ether or glycerol triglycidyl ether. The structure of PDA-L and GDA-L were analyzed by FTIR and 1HNMR, and the demulsification performance in water-in-oil emulsion was detailly evaluated by the bottle test. The results showed that PDA-L exhibited higher demulsification efficiency (DE) compared to GDA-L, attributed to its more appropriate amphiphilic characteristics. Judging by the results, when the dosage of PDA-L was 500 mg/L, the DE could achieve 100 % within 4 h at a temperature of 50 °C, and it also had excellent demulsification performance in a wide pH range (4–10) and high salinity. The competitive adsorption behavior of asphaltenes and PDA-L at the oil–water interface was studied by interfacial tension and three-phase contact angle. Moreover, the effect of PDA-L on the interfacial film strength was studied by coalescence time of droplets and viscoelastic modulus. Based on previous tests, a possible demulsification mechanism was proposed. PDA-L features a hydrophilic core and two extended hydrophobic alkyl chains, allowing it to readily move to the oil–water interface. This process facilitates the replacement of asphaltene and the formation of an unstable composite film, thereby promoting demulsification.

Effects of argon plasma treatment on carbon fiber surface characteric and its reinforcing polyimide composites interfacial properties at room and elevated temperatures

In high temperature conditions, this can cause considerable changes in the mechanical properties of the composite. In order to determine the structural and mechanical property changes that occur in composite materials at elevated temperatures, to elucidate the damage mechanisms at elevated temperatures, and to improve the stability and durability of the materials. This paper studies how plasma treatment time affects the surface polarity, roughness, wettability and mechanical properties of carbon fibers. The results showed that the best wettability was attained after 10 min of plasma treatment, and new oxygen-containing functional groups (COO- and -C=O) developed on the fiber surface. The fundamental explanation is that during plasma surface treatment, the CH group in the bisphenol A part chain segment present in the epoxy resin sizing agent's composition is oxidized, forming an organic oxide layer. In this paper, the plasma modification technology was utilized to improve the interfacial compatibility of carbon fiber and Polyimide (PI) resin, and the interlaminar shear strength reached 103.98 MPa, up 10.49 %, and the strength retention rate was 84.3 % at 300 °C. In this paper, the plasma modification technique was employed to increase the interfacial compatibility of carbon fiber and PI resin. It was found that the Inductively Coupled Plasma (ICP) treated carbon fiber surfaces underwent physical and chemical changes that effectively enhanced the interfacial compatibility with the resin. However, the chemical groups and physically etched regions on the surface of the plasma-modified fibers are able to impede the relative motion of the resin to a certain extent, thus improving the interfacial strength.

Micro-mechanical evaluations of adhesion properties for Cr-coated accident tolerant fuel cladding

The development of accident tolerant fuel (ATF) cladding has been encouraged to satisfy increased nuclear safety demands under accident conditions since Fukushima accident. Coating techniques using oxidation-resistant materials, such as Cr and Al, on existing Zr-alloy claddings have been widely applied as short-term solutions. However, coating delamination due to poor adhesion may reduce its benefits, such as low waterside corrosion/oxidation rates and fretting resistance, which necessitates accurate evaluation of coating adhesion suitability. In this study, micro-mechanical tests, micro-cantilever bending test and surface and interfacial cutting analysis system test, were conducted to qualitatively and quantitatively evaluate adhesion properties on a coated ATF cladding. In situ scanning electron microscopy-based micro-cantilever bending tests were performed using a pico-indenter equipped with a diamond flat tip. We present the results for magnetron-sputtered Cr-coated ATF claddings in detail. Micro-cantilever tests on the Cr-Zr interface revealed that deformation and failure primarily occurred in the Zr substrate, rather than at the interface. And the Cr-coated cladding showed highly adherent mechanical bonds, as evidenced by the interfacial strength and elastic modulus. SAICAS tests confirmed that peeling of the coating layer occurred only when the applied force exceeded the cutting force of the coating layer. The experimental results suggest that the Cr-coated cladding exhibited a sufficiently adherent mechanical bond to prevent delamination of the coating.

Ion-Mediated Molecular Bridging at Buried Interface Enhances Perovskite Solar Cell Durability.

Engineering heterointerfaces via molecular bridging has been crucial for achieving perovskite solar cells (PSCs) featuring optimal power conversion efficiencies (PCEs) and environmental durability. However, the challenge remains in ensuring interfacial mechanical reliability to enhance the long-term durability of PSCs. Herein, an ion-mediated molecular bridging strategy is intentionally exploited to improve the mechanical integrity between the perovskite bottom and electron-transport layers (ETLs) through balancing interfacial toughness and strength. As a demonstration of the concept, a zwitterionic guanylurea phosphate additive is preburied onto the SnO2 ETL, in which the guanylurea with bifacial NH2 groups servers as a molecular bridge connecting the perovskite and ETL through electrostatic coupling, while the phosphate can interact with charged species at the heterointerface to strengthen the mechanical contact. Benefiting from the robust heterointerfaces, the mechanical durability of flexible PSCs is significantly enhanced, retaining 91.3% of the original efficiency following 6000 bending cycles (bending radius = 3 mm). Additionally, the enhanced mechanical integrity at the buried interface also benefits the charge transfer and chemical stability in rigid PSCs, contributing to PCEs of over 25% as well as thermal stability with T86 of 1200 h under aging at 85 °C.

Damage characteristics and mechanisms of shear strength at the interface between fiber-reinforced concrete and rock under freeze-thaw cycles

In concrete reinforcement projects conducted in cold regions, freeze-thaw cycles contribute to the deterioration of the 'concrete-rock' interface strength. To examine the characteristics of shear stress and the evolution of damage at the interface of PVA fiber-reinforced concrete and rock under freeze-thaw conditions, a series of freeze-thaw shear tests were performed utilizing a self-developed fully saturated shear apparatus. This experimental approach was complemented by CT and scanning SEM analyses to investigate the structural changes at the interface under varying degrees of freeze-thaw damage. The findings revealed that the ECC-S specimens with PVA fibers exhibited an approximate 17.64 % increase in porosity and a 46.5 % reduction in rock strength after 45 freeze-thaw cycles. In contrast, OC-S specimens without PVA fibers experienced an approximate 10.51 % increase in porosity and a strength reduction of about 22.9 % under identical conditions. Furthermore, the study indicated that as the number of freeze-thaw cycles increased, the strength did not consistently rise with the angle of shear. A threshold was identified at an angle of 45°, beyond which the strength did not exhibit significant increases. This research holds considerable theoretical significance and practical implications for enhancing concrete reinforcement methodologies in cold regions, thereby ensuring the safe and efficient operation of rock engineering projects in such environments.