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For high-temperature superconducting (HTS) cables carrying substantial currents, the current carrying capacity of a single YBCO tape is limited, and multiple tapes need to be connected in parallel. The current sharing design of parallel YBCO tapes has emerged as a central concern in the HTS cable design. However, various tape parameters, including critical current I c , n-value, and joint resistance, can significantly influence the current distribution in the system. In this paper, the influence of YBCO tape parameters on the current distribution characteristics of the cable was studied. The results showed that the current distribution and quench characteristics were regulated by tape I c , tape n-value, and tape joint resistance together, and that meanwhile, the total current also served as an important factor. Significant influence of the joint resistance was also observed in the event of a limited total current, which was no longer obvious for a total current close to the total I c . For the parallel tapes with the same I c , the one with higher resistance quenched later, while in the case of the same resistance, the effect of the tape I c is greater than that of the tape n-value. [ABSTRACT FROM AUTHOR]

3D-printed anodes for bioelectrochemical systems are increasingly being reported. However, comparisons between 3D-printed anodes and their non-3D-printed counterparts with the same material composition are still lacking. In addition, surface roughness parameters that could be correlated with bioelectrochemical performance are rarely determined. To fill these gaps, slurries with identical composition but different mass fractions were processed into SiOC anodes by tape-casting, freeze-casting, or direct-ink writing. The current generation was investigated using electroactive biofilms enriched with Geobacter spp. Freeze-cast anodes showed more surface pores and the highest surface kurtosis of 5.7 ± 0.5, whereas tape-cast and 3D-printed anodes showed a closed surface porosity. 3D-printing was only possible using slurries 85 wt% of mass fraction. The surface pores of the freeze-cast anodes improved bacterial adhesion and resulted in a high initial (first cycle) maximum current density per geometric surface area of 9.2 ± 2.1 A m−2. The larger surface area of the 3D-printed anodes prevented pore clogging and produced the highest current density per geometric surface area of 12.0 ± 1.2 A m−2. The current density values of all anodes are similar when the current density is normalized over the entire geometric surface as determined by CT-scans. This study highlights the role of geometric surface area in normalizing current generation and the need to use more surface roughness parameters to correlate anode properties, bacterial adhesion, and current generation. [ABSTRACT FROM AUTHOR]

The insulating structure near the slot outlet of high-voltage generator stator coils is the typical bushing structure, which is prone to corona and has a decisive impact on the safety of the generator. In engineering, nonlinear resistance anti-corona tapes are usually bound with around the main insulation surface of the stator coils near the slot, to achieve the effect of homogenizing the electric field. Usually, the resistance nonlinearity is increased by adding semi conductive or conductive materials into the anti-corona tape. However, after the process of adding semi conductive or conductive materials, the breakdown strength of anti-corona tape is often reduced, resulting in that anti-corona tapes with good nonlinear cannot be applied. In order to have both good nonlinear resistance and breakdown strength, epoxy resin (EP) is used as a matrix, which is blended with one-dimensional structured carboxyl-functionalized multi-walled carbon nanotubes (MWCNTs) and zero-dimensional structured polyaniline (PANI) to obtain nonlinearly good materials in this paper. The nonlinear conductivity characteristics and breakdown characteristics were tested separately. The results show that compared to MWCNTs/EP composite materials, PANI-MWCNTs/EP composite materials have higher nonlinear coefficients and breakdown strength. The breakdown field strength of 0.5wt% MWCNTs/EP composites is 2.11 kV/mm, and the nonlinear coefficient is 1.41. In contrast, the breakdown field strength of 3wt% PANI-0.5wt% MWCNTs/EP was increased by 106.16%, and the nonlinear coefficient is as high as 5.32. In addition, with the increase in PANI doping amount, the nonlinear coefficient of PANI-MWCNTs/EP gradually increases, and the breakdown strength also gradually increases. It can be seen that doping PANI can improve the breakdown strength while maintaining the range of resistivity variation within the nonlinear material working field strength. This discovery can provide reference for the development of nonlinear anti-corona materials for subsequent high-voltage generators. [ABSTRACT FROM AUTHOR]

A superhydrophobic surface is an ideal choice to enhance the corrosion resistance of aluminum (Al) and Al-based alloys which are widely used in various industrial fields. However, there are limitations in the complex fabrication process, high cost, and easy damage of micro-nano structures for processing superhydrophobic Al surface. To address the aforementioned limitations, we presented an efficient and facile method via acid wet blasting method to fabricate micro-nano composite structures on the Al substrate and subsequently low surface energy modification to obtain superhydrophobic Al surface (SHP-AWBM-Al), which had a water contact angle of 162° and rolling angle of 3°. The fabricated SHP-AWBM-Al had excellent self-cleaning performance, anti-fouling ability, and good fog collection ability. Tape peeling test, sandpaper friction test, acidic solution corrosion test, alkaline solution corrosion test, and natural environment corrosion test showed that the SHP-AWBM-Al had good mechanical stability and chemical stability compared with the superhydrophobic Al surface (SHP-H-Al) obtained by chemical etching. In addition, the electrochemical corrosion test showed that the SHP-AWBM-Al was more corrosion-resistant than the SHP-H-Al. This finding could enhance the technology for fabricating superhydrophobic Al surfaces. [ABSTRACT FROM AUTHOR]

The article presents the results of computer simulation and experimental rolling of 0.55 mm thick, 100 mm wide tapes made of AD33 aluminium alloy on an industrial 175 × 300 double-roll mill under different contact friction conditions. The study quantifies the impact of technological lubricants on the distribution of rolling forces, moments, and powers along the tape length. It has been shown that the use of technological lubricants reduces the force and power parameters compared to dry rolling. When simulating the rolling process of tapes made of AD33 alloy with I40 technological lubricant (5%), the rolling force decreases by 6.72 kN (7.9%), the rolling moment—by 0.026 kNm (12.6%) and the rolling power—by 0.098 kW (12.8%) compared to dry rolling. When the rolls are lubricated with kerosene, the rolling force decreases by 8.8%, the rolling moment—by 18.8%, and the rolling power—by 18.6%. The results of computer simulation of rolling with various technological lubricants have led to the development and implementation of a new rolling mode on a 175 × 300 double-roll mill using I40 industrial oil as the technological lubricant. The new mode ensures the specified thickness accuracy of 0.55 ± 0.01 mm along the length of AD33 alloy tapes, significantly reduces the deformation time, and decreases the loads on equipment (by 5–8%) at the machine-building plant in Dong Nai city. [ABSTRACT FROM AUTHOR]

The alloy-reinforced Bi-2223 composite tapes can be used to realize high-magnetic field magnets, and its equivalent mechanical properties are important because of the great stress during the manufacturing and operation of magnets. Since the alloy-reinforced Bi-2223 tape has a complex structure, suitable analytical methods and equivalent models are necessary. The analysis of the equivalent mechanical properties is achieved by the mixture rule method and finite element simulation of simplified models. By using different simplified models, it is found that the single-filament elliptical model reduced computation time at most compared with the multi-filaments model, while the deviation from the experimental results is the minimum. It also shows that the details of the geometry in the models have little effect on the results. The results of the mixture rule method also agree with the experimental results, demonstrating that using the mixture rule method and simulation method of a single-filament elliptical model for mechanical analysis of alloy-reinforced Bi-2223 tapes is feasible. [ABSTRACT FROM AUTHOR]

Pressure-sensitive adhesive tapes are used in automotives, railway vehicles and construction, where flame retardancy is of major importance. This is why industrial applicants often buy, and industrial tape manufacturers often produce, flame-retardant adhesive tapes, advertised for their good flammability characteristics. Yet, how flame-retardant tapes influence the fire behavior of bonded materials is a rather open question. To investigate this issue, three different substrates were bonded, using eight double-sided adhesive tapes containing two different carriers and two different flame retardants. The bonded substrates were compared to their monolithic counterparts in terms of flammability, fire behavior and fire stability. The fire behavior of adhesive tape bonded materials differed significantly from the monolithic substrates. The usage of different adhesive tapes let to different burning behavior of the bonded materials mainly due to different carrier systems. In contrast, the implementation of flame retardant into the adhesive had rather minor or no effect on the burning behavior of the bonded substrates despite their positive effect on the flammability of the free-standing tape. The carrier changed the HRR curve in the cone calorimeter and was able to both, reduce and increase fire hazards. Using the carrier with the better fire performance can lower the fire growth rate by 20%, the peak of heat release rate by 27%, and the maximum average rate of heat emission by 30% in cone calorimeter tests. Overall, the fire behavior of bonded materials is a complex interaction between substrate, adhesive, and carrier, and depends on the fire scenario the materials are exposed to. [ABSTRACT FROM AUTHOR]

Circular pipe heat exchangers, widely used in process industries, rely on passive heat transfer augmentation techniques like twisted tape inserts to enhance thermal performance. The challenge lies in identifying the optimal insert design. This study applies hybrid multi-criteria decision-making (MCDM) techniques to address this challenge, aiming to identify the best twisted tape insert configuration for maximizing heat exchanger efficiency. For developing the method, twenty-one passive enhancement techniques have been identified. This study employs a holistic approach, considering eight parameters (surface–volume ratio, Nusselt number, friction factor, thermal performance factor, total investment cost, cost per efficiency and CO2 emissions) across four criteria (geometric, thermo-hydraulic, economic and environmental criteria) to optimize resource utilization while reducing environmental impact and minimizing costs. The Entropy-CRITIC (Criteria importance through inter-criteria correlation) weighing method (ECWM) was employed to find the weights of all parameters, and ranking of alternatives was done by TOPSIS (Technique of order preference similarity to ideal solution), COPRAS (Complex proportional assessment) and CoCoSo (Combined compromise solution) MCDM methods. These hybrid approaches, combining objective weighting with MCDM ranking, facilitated the identification of ideal twisted tape inserts. To ensure the robustness of the MCDM methods, sensitivity analysis, Spearman rank correlation and rank reversal techniques were employed for validation. COPRAS emerged as the most robust MCDM method, indicating cross-cut twisted tape as the optimal solution for heat transfer augmentation. This research demonstrates the effectiveness of MCDM techniques in selecting optimal sustainable passive inserts for enhancing the thermal performance of circular pipe heat exchangers. [ABSTRACT FROM AUTHOR]