Cable Applications Research Articles

Analysis of Insulation Properties for High Voltage Applications – A Review

Four popular plastic polymers (LLDPE, XLPE, LDPE and HDPE) that are frequently utilised in high voltage applications are thoroughly examined in the review. It highlights how crucial it is to choose the right insulating material based on your needs. HDPE is perfect for pipes and packaging due to its density and crystallinity. Because of its superior mechanical and thermal properties due to the cross-linking process, XLPE is the material of choice for electrical insulation. The low density, impact resistance and flexibility of LDPE are well known. The essay also examines initiatives to improve these materials, such as the use of nanofillers for XLPE in HVDC cable applications and the addition of alumina nanoparticles to HDPE to boost its dielectric qualities. In conclusion, XLPE excels in thermal stability and electrical insulation, HDPE in toughness and chemical resistance and LDPE in flexibility and impact resistance. The best material to use depends on the needs of the high voltage application. Overall, the essay offers a complete analysis of the characteristics and possible applications of LLDPE, XLPE, LDPE and HDPE in high voltage insulation.

Effects of Reynolds number and surface modification on wake-induced vibrations of two staggered circular cylinders

This study explores the role of Reynolds numbers (Re) in wake-induced vibrations (WIVs) of two cylinders, specifically wake galloping and two-degree-of-freedom coupled flutter on the downstream cylinder. The center-to-center distances between the cylinders were 3.0D −5.0D in along-flow direction and 0.0D −2.0D in cross-flow direction (D is the diameter of the cylinders). The Re ranged from 1.4 × 104–6.7 × 104, within the subcritical Re regime of a smooth cylinder. The supercritical Re regime was realized by winding 12 spiral protuberances along the cylinders to lower the critical Re. Descriptions of wake interference of two smooth cylinders at Re = 850–6.5 × 105 were summarized from the literature. Wake interference strongly depended on Re, even within the subcritical Re regime. WIVs mostly occurred in the upper subcritical Re regime with strong wake interference. In the supercritical Re regime, the wakes of the cylinders were narrowed and vortex shedding was suppressed. Consequently, the wake interference and WIVs were weakened or completely disappeared. The cylinders fitted with 12 spiral protuberances reportedly reached the supercritical Re regime at Re = 3.1 × 104. Resultantly, they were stable against WIVs above this Re even at close spacing, and suitable for stay cable applications.

Synergistically ceramization of rubber system for fire safety cable by sepiolite functionalized with boron-based nanoparticles

In this research, a novel ethylene propylene diene monomer rubber (EPDM) formulation for cable with high ceramization efficiency was prepared by the addition of functionalized sepiolite with boron fluxing compound nanoparticles (SEPTB) obtained by precipitation route. Non-functionalized sepiolite (SEP) has been incorporated to the system for reference. EPDM materials were characterized by standardized tests measuring their behavior against fire and important improvements were observed, especially in terms of smoke production (25% reduction of the smoke production compared with the formulation using SEP) presenting a remarkable behaviour against dripping and self-extinction when a flame is directly applied. The mechanism of ceramization under fire conditions was discussed. It was found that EPDM system with SEPTB additive transformed into a rigid ceramic after treating at 1000°C. In this particular case, the ceramization was more efficient due to the sepiolite transformation to enstatite at lower temperatures (∼750 vs ∼850°C) combined with the “in situ” formation of a glassy phase which notably enhances the reinforcement of the char layer by forming a reinforcing 3D enstatite fibers net structure that reduces smoke production and even totally avoids the dripping of melted polymer by the action of the heat in a fire event. This work provides new insights for the preparation of high-performance synergist additive based on sepiolite for the enhancement of fire retardance of EPDM system for cable applications.

Fundamental study on performances of fiber-superconducting composite CORC cable: electromagnetic, thermal, mechanical and quench behaviors

Abstract Common terminal voltage measurement can be hardly applied to detect quenches in long high temperature superconducting (HTS) conductor on round core (CORC) cable because not only the HTS normal zone propagation velocity (NZPV) is low but also immobilizing a large number of voltage leads is inconvenient. Distributed optical fiber sensing (DOFS) technology is a promising method for quench detection of long superconductors. To sense the thermal changes of CORC cables during quenches more directly and prevent optical fibers from damages by external stress, a fiber-superconducting composite (FSC) CORC cable was fabricated. For this cable, three optical fibers were placed in three grooves of the copper core respectively, then three HTS tapes were spirally wound on the copper core in sequence. Comparing to a traditional CORC cable, obviously, the FSC CORC cable structure has been changed. To promote FSC CORC cable engineering applications, it is necessary to study the fundamental performance of the cable. In this paper, we investigated the electromagnetic, thermal and mechanical properties of the FSC CORC cable by comparing those with a common one. The results demonstrated that, compared to the common one, the magnetic distribution of the FSC CORC cable hardly changed, but the current distribution of the copper core in the FSC CORC cable slightly changed which led to decreases of transport AC loss, in addition, the thermal characteristics of the FSC CORC cable was slightly changed and the bending tolerance ability of the cables reduced within a bending diameter range of 15 cm. What’s more, the embedded optical fibers combined with DOFS system are successfully used to detect the temperature changes of the cable surface. Finally, to study the quench behaviors of the cable, we built a quench detection platform, which equips with a voltage acquisition system, a thermocouple temperature acquisition system and the DOFS system. By using the platform to detect the quenches of the FSC CORC cable, minimum quench energy of the cable and NZPV of the tape and cable at different currents was tested.

Titanium Cable Cerclage Increases the Load to Failure in Plate Osteosynthesis for Distal Femoral Fractures.

Background and Objectives: The reduction of two-part oblique or spiral fractures of the distal femur using steel wire cerclage prior to plate osteosynthesis is a proven procedure. In addition to being useful in fracture reduction, wire cerclage was also shown to increase the stability of osteosynthesis. Nevertheless, metal corrosion and the allergenic potency of steel remain problematic disadvantages of this method. A biomechanical study was carried out to evaluate titanium cable cerclage as an alternative supplement for plate osteosynthesis of a distal femoral two-part fracture. Materials and Methods: An unstable AO/OTA 32-A2.3 fracture was created in eleven pairs of nonosteoporotic human cadaver femora. All the samples were treated with polyaxial angular stable plate osteosynthesis. One femur from each pair was randomly selected for an additional fracture fixation with multifilament titanium cable cerclage. Stepwise cyclic axial loading was applied in a load-to-failure mode using a servohydraulic testing machine. Results: All specimens (mean age: 80 years; range: 57-91 years) withstood a cycling force of at least 1800 N. With a mean load of 2982 N (95% CI: 2629-3335 N), the pressure forces resulting in osteosynthesis failure were significantly higher in specimens with an additional titanium cerclage (Group 1) than in samples that were solely treated with plate osteosynthesis (Group 2) at 2545 N (95% CI: 2257-2834 N) (p = 0.024). In both groups, cutting out the distal screws at the condyle region, resulting in shearing of the distal fragment proximal to the fracture line, was the most frequent cause of construct failure. Among the specimens assigned to Group 1, 36% exhibited a specific fracture pattern, namely, a fracture of the dorsal buttress above the cerclage. Analysis of axial stiffness (p = 0.286) and irreversible deformity of the specimens revealed no differences between the groups (p = 0.374). Conclusion: Titanium cable cerclage application, as a supplement to an angular stable plate, resulted in an increased load to failure. In terms of stability, the use of this adjunct for fracture fixation of supracondylar two-part oblique femoral fractures might, therefore, be an option, especially in patients who are sensitive to nickel.

The first engineering application of 10MN CFRP cables in cable-stayed bridge in China

Existing engineering applications typically involve carbon fiber reinforced polymers (CFRP) cables with relatively small ultimate tensile forces (less than 10MN). This study presents the engineering application of China's first thousand-ton-grade CFRP cable-stayed bridge. The optimal steel and CFRP hybrid cable system was determined through a comparative analysis of structural behavior and life cycle cost. Thereafter, the CFRP cable, consisting of 121 strands of φ7 CFRP tendons, along with its anchoring system, was designed and manufactured with a theoretical ultimate tensile strength of 10,710 kN (Pb). Subsequently, the mechanical properties of 7–121 CFRP cable were investigated and experimentally verified. The tensile test revealed a satisfied ultimate tensile bearing capacity of 10,805 kN. Furthermore, after two million fatigue cycles, the CFRP cables retained approximately 90 % of their theoretical ultimate force, highlighting their excellent fatigue resistance. Besides, no damage occurred with a maintained tension force of 0.45 Pb at a temperature of 150 °C for a duration of at least 30 min, meeting the requirements of specification. Moreover, the key procedures of CFRP cable installation were also claimed. This study aims to further promote the application and development of CFRP cables in larger span and even super-long span bridges.

Thermal propagation analysis of 2G HTS stacked wires based on a dimensional coupling method

Stacked structures of high-temperature superconducting (HTS) tapes are usually employed to enhance current-carrying capacity in cable or magnet applications, but their multilayer characteristics may result in local hot spots due to uneven cooling. Besides, the inconsistencies along the length of tapes introduced during manufacturing process and the significant transverse Lorentz forces experienced in magnet operations can lead to weak parts, bringing uncertainties to thermal stability. Finite-element methods are widely used to predict thermal propagations, but 3D models encounter challenges such as distorted mesh elements and convergence issues, particularly when combining electromagnetic and heat transfer modules for long-distance wires. In this work, we have developed a Dimensional Coupling Method (DCM) to assess the thermal impact of weak parts in stacked wires applying coupled 1D and 2D models. The 2D model analyzes the electromagnetic and heat characteristics of stacked surfaces, and provides an initial heat source for the 1D model, which evaluates thermal propagation longitudinally. Simulation results of the 1D module are then transferred back to update the 2D outcomes. Models of distinct dimensions are coupled sequentially in physical steps but simultaneously in the time domain. Our approach is verified by 3D model benchmarks and offers a computational cost reduction of approximately 60 % compared to the benchmarks, making it more suitable for applications with large Iop/Ic ratios. Specially, multi-layer stacked wires under low ratios cases are also been analyzed. What’s more, two influencing factors of heat propagation, the weak-part length and position, are also investigated.

Simulation and characterization of Co3O4/carbon nanotube-filled PVC nanocomposites for medium-voltage cable applications

Simulation and characterization of Co3O4/carbon nanotube-filled PVC nanocomposites for medium-voltage cable applications

Mixed-mode fracture analysis of CORC cables with double-edge cracks under tension and torsion

The Conductor on round core (CORC) refers to a circular cable that is helically wound with rare-earth-barium-copper-oxide ((RE)BCO) high-temperature superconducting (HTS) tapes. This type of cable finds extensive applications in large superconducting magnets. However, the mechanical–electrical performance of CORC cables is hindered by microscopic edge cracks that occur during the mechanical slitting process of HTS tapes. In this paper, the mixed-mode stress intensity factor (SIF) of cracks in CORC cables under different loading conditions is investigated using the extended finite element method (XFEM). The design variables of CORC cables are optimized by considering the effect of various factors such as the crack parameter, the winding angle, the core radius, and the Poisson’s ratio of the winding core on the SIF. The results indicate that the impact of each factor on the mixed-mode SIF varies depending on the loading mode. Notably, the influence of the winding angle on the SIF is particularly significant and intricate. In the case of tensile loading, a smaller winding angle proves advantageous in impeding crack propagation. Conversely, the most dangerous winding angle for torsional loads is 45°. The divergence of these effects can be indirectly indicated by theoretical solutions regarding the tape strain along the helix direction. For the cases examined, the results have shown that the crack propagation path is independent of these factors, and the direction of propagation is perpendicular to the edge of the tape.

Real-Time Monitoring of Cable Sag and Overhead Power Line Parameters Based on a Distributed Sensor Network and Implementation in a Web Server and IoT.

Based on the need for real-time sag monitoring of Overhead Power Lines (OPL) for electricity transmission, this article presents the implementation of a hardware and software system for online monitoring of OPL cables. The mathematical model based on differential equations and the methods of algorithmic calculation of OPL cable sag are presented. Considering that, based on the mathematical model presented, the calculation of cable sag can be done in different ways depending on the sensors used, and the presented application uses a variety of sensors. Therefore, a direct calculation is made using one of the different methods. Subsequently, the verification relations are highlighted directly, and in return, the calculation by the alternative method, which uses another group of sensors, generates both a verification of the calculation and the functionality of the sensors, thus obtaining a defect observer of the sensors. The hardware architecture of the OPL cable online monitoring application is presented, together with the main characteristics of the sensors and communication equipment used. The configurations required to transmit data using the ModBUS and ZigBee protocols are also presented. The main software modules of the OPL cable condition monitoring application are described, which ensure the monitoring of the main parameters of the power line and the visualisation of the results both on the electricity provider's intranet using a web server and MySQL database, and on the Internet using an Internet of Things (IoT) server. This categorisation of the data visualisation mode is done in such a way as to ensure a high level of cyber security. Also, the global accuracy of the entire OPL cable sag calculus system is estimated at 0.1%. Starting from the mathematical model of the OPL cable sag calculation, it goes through the stages of creating such a monitoring system, from the numerical simulations carried out using Matlab to the real-time implementation of this monitoring application using Laboratory Virtual Instrument Engineering Workbench (LabVIEW).

Performance investigation of hydrothermally stressed polyamide nanocomposites for insulation applications

This paper investigates the performance of novel nano ZnO filled polyamide nanocomposites under hydrothermal conditions for cable insulation applications. Neat polyamide (PA0) and its nanocomposite with 0 wt% (PA0), 1 wt% (PA1), 3 wt% (PA3), 5 wt% (PA5), and 7 wt% (PA7) of nano ZnO were prepared and subjected to accelerated hydrothermal aging conditions in a programmable chamber at 85 °C and 85% relative humidity for 300 h. The samples were analyzed with visual inspection, hydrophobicity evaluation, optical microscopy, Fourier Transform Infrared (FTIR) spectroscopy, leakage current and UV–vis spectroscopy after every 100 h of aging. Scanning Electron Microscopy (SEM) and x-ray Diffraction (XRD) were employed for analyzing filler dispersion. Maximum filler dispersion was achieved in the case of 3 wt% of nanofiller. All the samples expressed surface degradation and increase in leakage current after aging. Maximum surface roughness and highest leakage current of 7 μA were noticed for PA0, however PA3 expressed lowest leakage current and surface degradation. PA0 expressed the lowest hydrophobicity class of HC-3 and lowest contact angle of 75° after aging. Among the nanocomposites, PA3 expressed the highest hydrophobicity class (HC-1) and contact angle (112°) after aging. FTIR results expressed that all the samples suffered from oxidation and the C=O peaks at ∼1728 cm−1 increased by 120%, 100% and 120% for PA1, PA3 and PA7 respectively. The peaks of –OH group at ∼3500 cm−1 increased for all the sample indicating moister absorption. However, it is observed that the addition of nanofiller enhanced the overall performance of composites and among the composites PA3 performed better.

Secure and Efficient Federated Learning for Smart Optical Cable Monitoring Systems

This study presents a pioneering federated multi-modal data classification model tailored for smart optical cable monitoring systems. By harnessing federated learning techniques, the model ensures data privacy while achieving performance on par with centralized models. Through comprehensive experiments spanning various modalities, including vision and auditory data, our approach showcases promising outcomes, as evidenced by accuracy and precision metrics. Furthermore, comparative analyses with centralized models highlight the superior data security and reduced network strain offered by federated learning. Moreover, we delineate the design and deployment of a smart optical cable monitoring system leveraging edge computing, accentuating the pivotal role of information technology in elevating operational efficiency within the cable monitoring domain. Through meticulous analysis and simulations, our proposed system adeptly monitors environmental variables, thereby bolstering safety and efficiency in smart optical cable monitoring applications.

Novel dual‐resonance damped alternating current testing system for offline partial discharge measurement of power cables

AbstractTo accurately detect the early deterioration of electrical insulation in power cables, an energizing system is required for offline partial discharge (PD) measurements. The damped alternating current (DAC) testing system has emerged as an effective tool for inducing PD events. However, the existing systems often suffer from limitations such as signal interference, low sensitivity, and high costs. To address these issues, this study proposes a novel dual‐resonance DAC testing system that is simple in structure and cost‐effective. The prototype was built for testing 10‐kV distribution cables, and its effectiveness was validated through experimental tests on a cable sample. The results show that this approach significantly improves PD detection sensitivity and successfully completes PD localization. This research contributes to the development of more efficient and affordable DAC generation technology for power cable testing applications.

Artificial Intelligence Assisted Smart Self‐Powered Cable Monitoring System Driven by Time‐Varying Electric Field Using Triboelectricity Based Cable Deforming Detection

AbstractCable monitoring is essential for the prevention of machine malfunctions as machines are operated dynamically. Traditional methods of cable monitoring, conducted through portable or fixed devices, possess the inherent limitations in real‐time damage detection and precise location identification. Herein, a self‐powered, smart cable monitoring system is proposed, utilizing a triboelectric nanogenerator (TENG) as a sensor for the cable and an electric field energy harvester (EFEH) as a power source of the system. Also, the generated electrical outputs from the EFEH are theoretically and experimentally investigated according to the EFEH‐layer numbers, and the optimal number of EFEH‐layers is determined, generating an average electrical power of 2.04 mW. Through hybridization of TENG and EFEH, a synergistic effect is confirmed, resulting in a remarkable 155% enhancement in electrical energy. Consequently, the proposed system is endowed with self‐powered wireless communication capabilities. Additionally, employing a pre‐trained long short‐term memory‐based model, the system can predict the remaining lifespan of the cable with an accuracy rate of 93.7%. Considering these results, the proposed system demonstrates significant potential for industrial cable monitoring applications in the near future.

Dielectric Properties of Polypropylene Blended with Ethylene-Butene Elastomer for High Voltage Applications

In recent years, polypropylene (PP) has been tremendously explored in high voltage cable applications due to its outstanding thermal and electrical properties. Furthermore, PP is an environment-friendly material that can be recycled, thus making it a promising candidate to replace conventional crosslinked polyethylene. However, the stiffness and brittleness of PP need to be further modified so that it can be utilized for practical cable applications. Recently, elastomer blending has been one of the favorable methods used by the industry to modify PP flexibility. Unfortunately, different types of elastomers bring different compatibility in the PP matrix. In this paper, the dielectric performance of PP, when mixed with ethylene-butene elastomer (EBE), was investigated. The thermal behaviors and morphological analysis were identified by using a differential scanning calorimeter and scanning electron microscopy, respectively. Meanwhile, the direct current (DC) breakdown strength was set up referring to the ASTM D3755 standard. Based on the findings, EBE shows a certain degree of compatibility with PP, where uniformly distributed spots were observed. Although the addition of EBE slightly degraded the DC breakdown properties of PP, the performance of PP/EBE blends at low elastomer contents is still good enough compared to conventional XLPE.

Effect of Ethylene-Propylene-Diene Monomer Blending on the Dielectric Properties of Polypropylene for Power Cable Insulation

Thermoplastic materials such as polypropylene (PP) are ideal candidates to be used as power cable insulation materials. However, the mechanical properties of PP, which is brittle and stiff, need to be modified to meet the requirements of power cable insulation applications. To overcome this, ethylene-propylene-diene monomer (EPDM) can be melt blended with PP to improve PP’s mechanical properties. In the current work, the effect of blending different contents of EPDM with PP was investigated in terms of the morphology, chemical structure, dielectric response, electrical, and mechanical properties. The results show that the EPDM blended well with the PP as the EPDM dispersed in the PP structure. Meanwhile, the chemical structure and dielectric response of the EPDM and PP blend became slightly different with high contents of EPDM, which subsequently affected the breakdown strength and mechanical properties. Nevertheless, it is worth noting that PP blended with low contents of EPDM has the potential to be used as recyclable power cable insulation materials.

Tailoring electrical properties of PVC/PEC/Co3O4 nanocomposites by electron beam irradiation for advanced medium voltage cable applications

This study aimed to investigate the effects of electron beam irradiation on the structural, optical, and electrical properties of polyvinyl chloride/pectin (PVC/PEC) nanocomposites incorporating hexagonal nanoplate Co3O4. Hexagonal nanoplate Co3O4 was synthesized and incorporated into PVC/PEC blends at 5 wt%. The nanocomposites were subjected to electron beam irradiation at varying doses (0, 10, 20, and 30 kGy). Various characterization techniques, including XRD, UV–Vis spectroscopy, AC conductivity, and dielectric measurements, were employed to analyze the irradiated samples. Additionally, electric field distribution simulations were performed for a 33 kV cable model. XRD analysis revealed the retention of Co3O4 crystallinity up to 30 kGy, while the polymer matrix showed degradation above 10 kGy. The optical bandgap decreased from 2.25 eV to 1.90 eV with increasing irradiation dose, indicating changes in the electronic structure. The optimized AC conductivity (37.17 × 10−6 S m−1) and minimum relative permittivity (2.28) were achieved for the 30 kGy irradiated sample with 5 wt% Co3O4. The electric potential distribution gradually decreased from 33,000 V to zero V. The systematic variations in structural, optical, and electrical properties demonstrated controlled tuning of charge transport mechanisms, making these nanocomposites potentially suitable for advanced cable systems. The simulation results showed that the inclusion of Co3O4 at 30 kGy helped maintain a uniform electric field distribution in the 33 kV cable model compared to an unfilled cable.

Application of suspended inter-array power cables in floating offshore wind farms

The aim of the present study is to propose an engineering approach of designing suspended inter-array power cable configuration for offshore wind farms. To achieve this, a spar type and a semi-submersible type floating offshore wind turbines (FOWTs) are modeled in the dynamic analysis software OrcaFlex. The accuracy of these models is validated against reference studies. Several different cable configurations connecting two spar FOWTs are assessed based on Fitness Factors using static and dynamic analyses. The non-linear bending behavior and the marine growth effects are considered in the analyses. The number of buoys is found to be the main parameter affecting the maximum effective tension and the minimum bending radii of the cables. The buoy spacing determines whether the cable touches the seabed, floats fully submerged, or floats at the sea surface. The influence of the cable length and the marine growth on the observed cable tensions and curvatures is small for the investigated configurations. The optimum cable configuration found for the two spar FOWTs is employed to connect two semi-submersible FOWTs. The influence of the floater type on the suspended power cable tension and curvature is found to be negligible. Analysis of power cable behavior in an offshore wind farm layout shows that a two-turbine setup with different environmental load directions can be used as a representative case for the suspended power cables design of the entire wind farm.

A parameter-free fault location method for cross-bonding cable based on ranging equations

With the increasing application of long-distance high-voltage cables using the cross-bonding grounding method in urban power grids, the effectiveness and accuracy of the single-phase short-circuit fault location method for cross-bonded cables have gradually gained attention. To reduce positioning errors caused by inaccurate or unknown line parameters, a fault location method independent of line parameters is proposed. Firstly, the changes in sheath circulating current before and after the fault occurrence are analyzed, and based on these changes, a criterion for fault identification is established to determine the approximate range of fault occurrence. Secondly, considering the three-phase electromagnetic coupling of cross-bonded cables, an equivalent model for single-phase short-circuit faults in cross-bonded cables is established based on the double-π model. The along-line voltage and current are calculated by deducing electrical quantities at the ends of the cable. Then, the fault location equations are formulated based on the fault section, and the trust-region algorithm is employed to solve for fault distances and unit-length parameters of the cable in each equation group. Finally, a cable fault model is built using the PSCAD/EMTDC simulation platform, and the influence of different factors on the fault location method is analyzed. The results show that the fault location error of the proposed method is around 0.2 %, demonstrating high accuracy.

Enhanced Electrical Conductivity of Graphene-Incorporated Copper Wire and its Performances on Coaxial Cable Application at Sub 6 GHz

Intensive global research is focused on advanced conductive materials to meet the electrical requirements of the telecommunication and power industry. The primary aim is to enhance electrical conductivity, resulting of improved current-carrying capacity and reduced energy loss during transmission. Copper and its composites are vital for power transmission and telecommunications due to their electrical, thermal, and mechanical qualities. However, current methods have drawbacks, such as compromised conductivity with alloying. Graphene, an extraordinary carbon allotrope with exceptional properties and high conductivity, offers promising opportunities for the development of superior materials; such as graphene-incorporated copper (GrCu). The incorporation of graphene into copper wire holds significant potential for various industries, including electronics, energy transmission, and telecommunications, where high conductivity and reliability are paramount. This study investigates GrCu characteristics through mixing graphene and copper, vacuum melting, fine copper wire drawing, and GrCu coaxial cable manufacturing. Graphene infusion enhances conductivity and mechanical properties, altering microstructure and inducing twin boundaries in copper grains. Graphene's disruption during wire drawing triggers this effect, elevating wire conductivity to 103.5% by IACS. GrCu coaxial cable demonstrates performance coherence with HFSS simulation up to 6 GHz. Graphene's inclusion offers tailored material properties. Ongoing research promises further optimization and advancement of graphene-copper composites, paving the way for novel technological progress.