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Multi-channeled nerve guidance conduit is a prospective way to repair peripheral nerve injury, which is still difficult to be fabricated. A novel extrusion-stretching method was utilized in this study to produce multi-walled carbon nanotubes (MWCNTs) loaded multi-channeled nerve conduits with improved flexibility and versatility. The channels and geography of the conduits were tunable. The results showed that the mechanical properties of the multi-channeled nerve conduits were suitable for peripheral nerve restoration. MWCNTs increased the biocompatibility of the multi-channeled nerve conduits. This study proved that the MWCNTs loaded multi-channeled produced by extrusion-stretching method have great potential to repair peripheral nerve injury. [ABSTRACT FROM AUTHOR]

Conduits are plastic tubes extensively used to safeguard electrical cables, traditionally made from PVC. Recent safety guidelines seek alternatives due to PVC's emission of thick smoke and toxic gases upon fire incidents. Polypropylene (PP) is emerging as a viable alternative but requires modification with suitable halogen-free additives to attain flame retardancy (FR) while maintaining high mechanical strength and weathering resistance, especially for outdoor applications. The objective of this study was to develop two FR systems for PP: one comprising a cyclic phosphonate ester and a monomeric N-alkoxy hindered amine adjuvant achieving V0, and another with hypophosphite and bromine moieties, along with a NOR-HAS adjuvant achieving V2. FR performance along with mechanical properties, physicochemical characterization, and dielectric behavior were evaluated prior to and after 2000 h of UV weathering or heat ageing. The developed FR systems set the basis for the production of industrial-scale masterbatches, from which further optimization to minimize FR content was performed via melt mixing with PP towards industrialization of a low-cost FR formulation. Accordingly, two types of corrugated conduits (ø20 mm) were manufactured. Their performance in terms of flame propagation, impact resistance, smoke density, and accelerated UV weathering stability classified them as Halogen Free Low Smoke (HFLS) conduits; meanwhile, they meet EU conduit standards without significantly impacting conduit properties or industrial processing efficiency. [ABSTRACT FROM AUTHOR]

Tissue engineering constitutes the most promising method of severe peripheral nerve injuries treatment and is considered as an alternative to autografts. To provide appropriate conditions during recovery special biomaterials called nerve guide conduits are required. An ideal candidate for this purpose should not only be biocompatible and protect newly forming tissue but also promote the recovery process. In this article a novel, multilayered biomaterial based on polyvinylpyrrolidone, collagen and chitosan of gradient structure modified with conductive nanoparticles is presented. Products were obtained by the combination of electrospinning and electrospraying techniques. Nerve guide conduits were subjected to FT-IR analysis, morphology and elemental composition study using SEM/EDS as well as biodegradation. Furthermore, their effect on 1321N1 human cell line was investigated by long-term cell culture. Lack of cytotoxicity was confirmed by XTT assay and morphology study. Obtained results confirmed a high potential of newly developed biomaterials in the field of nerve tissue regeneration with a special focus on injured nerves recovery. [ABSTRACT FROM AUTHOR]

The core-shell structure conduit with conductive, antibacterial, and highly piezoelectric properties was designed and fabricated by a multi-step process. First, the shell structure was fabricated by rolling the co-electrospun mats of polycaprolactone/polyvinylidene fluoride and gelatin incorporated with polyaniline/graphene (PAG) nanocomposites. Then, the fabricated mats were filled with gelatin/chitosan hydrogels containing PAG and zinc oxide nanoparticles. Characterization of the intermediate materials and the final conduit revealed high electrical conductivity and remarkable output voltage for shell and core materials. MTT assay and antibacterial tests confirmed bioactivity and antibacterial properties of shells and cores. The results confirmed appropriateness of the conduit for nerve regeneration applications. [ABSTRACT FROM AUTHOR]

To improve the efficiency and protection level of combustible gas explosion relief in urban underground pipeline corridors, we built a 150 × 150 × 2000 mm³ transparent pipeline experimental platform to simulate underground pipeline corridors and studied the effect of different positions and diameters of explosion relief conduits on the side of the pipeline on the characteristics of the explosion of methane in the pipeline. The results show that the flame is twisted and deformed at the bend, increasing the contact area between the fuel and oxygen, thus causing flame acceleration. Wall conduit relief bend in the flame has a certain hysteresis, in the front end of the bend, and the back end of the pipe wall conduit were installed, the flame propagation time of 254 ms, and 200 ms, respectively, increased by 71 ms, and 17 ms, the delay ratio of 38.80%, 9.29%, respectively. When the front part of the pipe wall conduit pipe diameter of 60 mm, 80 mm, and 100 mm, the flame propagation time was delayed 71 ms, 82 ms, and 105 ms, the delay ratio of 38.80%, 44.81%, 57.38%, and the position of the front of the pipe wall conduit pipe diameter is larger, the lower the peak explosion pressure. [ABSTRACT FROM AUTHOR]

The article deals with increasing the mechanical properties of stainless steel 316 Ln-IG, which is intended for work in cryogenic temperatures (liquid nitrogen and liquid helium), such as conductor conduits for the ITER magnet system. The strength and plastic properties were increased by a combination of cold and cryo-rolling and heat treatment. The mechanical properties of rolled material were investigated at 293 K, 77 K, and 4.2 K. The work-hardening rate of the steel increased continuously with a lowering of the temperature. The maximum yield strength and ultimate tensile strength were achieved by the cryo-rolling process with a total thickness deformation of 50%. The material properties tested at ambient temperature were 0.2YS = 1050 MPa, UTS = 1200 MPa, and at 4.2 K, the values were 0.2YS = 1804 MPa and UTS = 2081 MPa. Two types of long-term heat treatment were applied after experimental rolling (823 K and 1093 K for 10 h). The highest precipitation hardening of steel was achieved at a temperature of 823 K after 50% deformation. The resulting grain size decreased from the initial 216 μm (before the rolling process) to 70 μm after ambient rolling and 72 μm after cryo-rolling. [ABSTRACT FROM AUTHOR]

Transparent conductors (TC) have been widely applied in a wide range of optoelectronic devices. Nevertheless, different transparent spectral bands are always needed for particular applications. In this work, indium tin oxide (ITO)-free TCs with tunable transparent bands based on the film structure of TiO2/Ag/AZO (Al-doped ZnO) were designed by the transfer matrix method and deposited by magnetron sputtering. The transparent spectra and figure-of-merit (FOM) were effectively adjusted by precisely controlling the Ag layer's thickness. The fabricated as-deposited samples exhibited an average optical transmittance larger than 88.3% (400–700 nm), a sheet resistance lower than 7.7 Ω.sq−1, a low surface roughness of about 1.4 nm, and mechanical stability upon 1000 bending cycles. Moreover, the samples were able to hold optical and electrical properties after annealing at 300 °C for 60 min, but failed at 400 °C even for 30 min. [ABSTRACT FROM AUTHOR]

Polymers are one of the most widely used chemicals in the oil and gas industry. They are used for mobility control in enhanced oil recovery, in conformance control as a cross-linked plugging agent, as a fracking fluid for fracture propagation and proppant transportation, and in drilling fluids as an additive for drilling mud enhancement. This research characterizes the polymer injectivity in different pore sizes under different conditions and evaluates the polymer conditions after injection. Based on this, the ability to reinject the polymer in the porous media is discussed. The factors studied include the pore size, the polymer concentration, the polymer injection flowrate, and polymer injectivity. When the porous media size was reduced to 1.59 mm (1/16th of an inch), the injectivity value reduced significantly, reaching less than 0.2 mL/min/psi and the polymer degradation increased primarily due to shearing. Results also showed that the polymers underwent four main degradations during injection including dehydration, syneresis, shearing, and excessive hydrolysis. In continuous fractures, the degradation is a strong function of the fracture size, length, and the polymer structure. The experimental results showed that one or more of the polymer degradations resulted in the inability to reinject the polymer in most cases. [ABSTRACT FROM AUTHOR]

This study provides the operation recommendations for the tension fittings used on a 63 kV overhead transmission line conductor based on experimental tests. In this way, the tension fittings, including the dead-end clamp, the mid-span joint, and the repair sleeve, are assembled on the lynx conductor under different faulty and healthy assembly conditions in the laboratory. The lynx conductor is one of the widely used conductors in the 63 kV overhead power lines. The electric current injection test, along with thermal imaging and also tensile test, are conducted on the studied samples. The results show that the surface temperature of the lynx conductor is higher than the surface temperatures of the dead-end clamp and mid-span joint under normal and overload current conditions. Also, the crimping pressure of the aluminum and steel pipes less than the standard value, the crimping length of the steel cores of conductor less than the standard value, and the crimping length of the aluminum pipes more than the standard value can lead to a developmental defect which should be repaired or replaced at the first opportunity of the transmission line service outage. The repair sleeve is under more thermal stress than the dead-end clamp and mid-span joint, even in the standard assembly condition. A slight temperature difference of a repair sleeve compared with the same type fitting may be a severe operating condition. Also, the use of two consecutive repair sleeves to cover the conductor cut strands is not recommended. Furthermore, the loose connection of bolts at the junction of the jumper terminal to the dead-end clamp causes a very high temperature which should be repaired immediately. If the temperature difference between two defective and healthy dead-end clamp or mid-span joint is more than 13 °C, a critical defect is diagnosed; however, the temperature difference between two repair sleeve more than 7 °C indicates a critical operation condition for defective one. [ABSTRACT FROM AUTHOR]

We investigate theoretically the origins of observed variations in the critical currents of Nb/Al-AlO x /Nb Josephson junctions in terms of various types of disorder. We consider the following disorder sources: vacancies within the Al layer, thickness variations in the AlO x layer, and "pinholes" (i.e., point contacts) within the AlO x layer. The calculations are all performed by solving the microscopic Bogoliubov–de Gennes Hamiltonian self-consistently. It is found that a small concentration of vacancies within the Al layer is sufficient to suppress the critical current, while the presence of a small number of thick regions of the oxide layer induces a similar effect as well. The pinhole scenario is found to result in anomalous behavior that resembles neither that of a pure tunnel junction nor that of a superconductor–normal–superconductor junction but a regime that interpolates between these two limits. We comment on the degree to which each of the three scenarios describes the actual situation present in these junctions. [ABSTRACT FROM AUTHOR]

Dynamic resistance plays an important role in certain high-Tc superconducting (HTS) applications where an HTS coated conductor carries a DC current exposed to an AC magnetic field. Here, we report measurements of the dynamic resistance in a 4 mm-wide YBCO coated conductor under a perpendicular AC magnetic field at 77 K, 70 K, and 65 K. Dynamic resistance was measured at three different frequencies for the reduced current, i (It/Ic0), ranging from 0.04 to 0.9, where It is the DC current level and Ic0 is the self-field critical current of the conductor at each temperature. At all three temperatures, the threshold magnetic field (Bth) values increase with reducing DC current. These results show that, for a given set of applied conditions, dynamic resistance decreases with decreasing operating temperature, which we attribute to the temperature dependent increase in the critical current of the wire. We show that measured Bth values at all three temperatures agree well with the analytical values from nonlinear Mikitik and Brandt equation for i ≤ 0.2 and with a simple linear expression that assumes a current-independent penetration field for i > 0.2. We further show the measured Bth curves at different temperatures normalized by critical current density collapse into one common curve. The above result implies that dynamic resistance in coated conductors at different temperatures under perpendicular AC magnetic fields can be scaled simply using measured Ic0 values at those temperatures and analytical equations. [ABSTRACT FROM AUTHOR]

Experimental data reveal that the classical description of transport ac losses in high-temperature superconducting (HTS)-coated conductors (CCs), based on investigations at low frequencies, is incomplete in some aspects when transport currents in the kilohertz range are considered. More specifically, above a certain "transition frequency," the ac losses per cycle no longer increase with the frequency as the theory predicts. Using a finite element model to allow for loss separation, we find that this phenomenon is caused by a combination of several factors that appear only above the transition frequency: the hysteresis and ferromagnetic losses per cycle are no longer independent of the frequency, while the eddy current losses per cycle no longer increase proportionally to the frequency. Based on a circuit model, we propose that the physical reason for this is that when the frequency increases, part of the supercurrent starts migrating into the metallic path. We argue that the current in the metallic path is not an eddy current but a transport current inductively coupled to the superconducting current. Finally, we discuss the relationship between the magnetic material magnetization, the critical current, and the transport current frequency. This study provides explicit insights into the frequency-dependent transport ac losses of HTS CCs in a broad frequency band, which is valuable for the design and optimization of HTS CC-based power devices. [ABSTRACT FROM AUTHOR]

As an indispensable part of wearable devices and mechanical arms, stretchable conductors have received extensive attention in recent years. The design of a high-dynamic-stability, stretchable conductor is the key technology to ensure the normal transmission of electrical signals and electrical energy of wearable devices under large mechanical deformation, which has always been an important research topic domestically and abroad. In this paper, a stretchable conductor with a linear bunch structure is designed and prepared by combining numerical modeling and simulation with 3D printing technology. The stretchable conductor consists of a 3D-printed bunch-structured equiwall elastic insulating resin tube and internally filled free-deformable liquid metal. This conductor has a very high conductivity exceeding 104 S cm−1, good stretchability with an elongation at break exceeding 50%, and great tensile stability, with a relative change in resistance of only about 1% at 50% tensile strain. Finally, this paper demonstrates it as a headphone cable (transmitting electrical signals) and a mobile phone charging wire (transmitting electrical energy), which proves its good mechanical and electrical properties and shows good application potential. [ABSTRACT FROM AUTHOR]

The dynamic resistance of a superconductor appears if it carries a direct current (DC) current and is simultaneously exposed to alternative current (AC) magnetic fields if its amplitude is higher than its full penetrated field. Due to its strong anisotropy, the dynamic resistance of high-temperature superconducting (HTS) tape is not only affected by the magnitude of AC magnetic fields but also their orientations. In particular, the dynamic resistance has considerable effect on the current distribution in HTS cables (except for Roebel cables) and even cable-in-conduit conductors made from those HTS cables, except for dissipative loss. This paper presents the behavior of dynamic resistance in an HTS quasi-isotropic strand (Q-IS), which consists of four sub-stacked 2G HTS tapes proposed by our group at North China Electric Power University, while it carries a DC current and simultaneously experiences an AC magnetic field with different magnitudes and orientations. An angular dependence of dynamic resistance in a single 2G HTS tape in an AC magnetic field with various orientations is first performed in simulations and experiments, respectively. The experimental results are in good agreement with the simulated ones, which shows that the dynamic resistance of a Q-IS also exhibits quasi-isotropic characteristics and has an important effect on the distribution of DC transport current. The related results are promising for the design and application of other DC HTS cables, feeders and magnets. [ABSTRACT FROM AUTHOR]

This paper presents a simple but rigorous method to extract correctly the resistivity of the superconducting Rare-Earth Barium Copper Oxide (REBCO) layer of High Temperature Superconductor coated conductors, when the latter are characterized in over-critical current conditions using ultrafast V - I pulsed current measurements. The pulsed current measurement method is used to reduce the amount of heat generated by the strong current flowing in the sample, but it cannot prevent it completely at current levels well above the critical current. In order to estimate accurately the temperature rise, we developed the so-called "Uniform Current" (UC) model, which consists in a static current sharing model coupled with a 2D thermal solver. The model assumes that the electric field is uniform over the sample cross section. It has been shown that this hypothesis works fine at high currents, but for lower current levels, although still higher than the critical current, one must wait until the magnetic relaxation effects disappear before using the outputs of the UC model. We also derived a theoretical bound for the error related to magnetic relaxation, which can be estimated experimentally by using a rectangular pick-up coil located just above the sample surface. After applying the UC model on an experimental set of data, one obtains a whole set of data points defining the resistivity ρ (J , T) of the REBCO superconductor being characterized. [ABSTRACT FROM AUTHOR]

Approximately 58% of wire failures are caused by slippage and fracture of electrical connectors, and the crimping quality analysis of connectors is based on equivalent cross-sectional stiffness. First, a JL/GLA 400/35 steel cord aluminum strand and NY-400/35 strain clamp are selected to fabricate 26 groups of specimens with different pipe penetration depths, opposite edge distances, inner diameters of the aluminum tube, and die widths. Then, through crimping tests on the aluminum tube and conductor and the steel core and steel anchor, five main crimping failures, namely, the slip at the outlet of the clamp, the slip at the outlet of the clamp with some broken aluminum strands, fracture of the aluminum tube in the non-pressure area, wire fracture at the outlet of the clamp, and separation of steel anchors, are observed. Finally, a failure analysis method for conductor crimping is proposed based on equivalent cross-sectional stiffness. Through the analysis of grip force and crimping quality, four failure modes and simplified curves of the load–displacement curve are obtained, and the failure principle of the conductor crimping is further elaborated. The results show that the stress release caused by the steel core and steel anchor of the crimping wire and the crimping aluminum tube and wire is the main reason for the slippage and fracture of the transmission line conductors and that it is also the key to improve the installation quality of the transmission line. [ABSTRACT FROM AUTHOR]

In a typical Nb3Sn cable for fusion applications, the knowledge of the strain state of Nb3Sn filaments is important to predict and interpret the conductor performance in operation. Amongst the relevant strain sources, the predominant is the thermal strain that arises during the cool-down of the conductor to operating temperature, due to the different expansion of Nb3Sn and copper in the cable and the stainless steel conduit. This work addresses the characterization of Nb3Sn thermal strain in the React & Wind prototype (RW2) developed by EPFL-SPC for the toroidal field coil and the central solenoid of the EUROfusion DEMO fusion reactor. AC susceptibility measurements were performed on the RW2 prototype to assess the thermal strain distribution in the cable cross-section, before and after undergoing electromagnetic and thermal cyclic loading. The results of the analysis have shown that RW2 exhibits a significantly lower absolute mean strain value (about −0.3%), compared to many Wind & React ITER conductor samples investigated with the same method. In addition, the analysis highlighted that the assessed thermal strain distribution does not vary significantly before and after the electromagnetic and thermal cycles, confirming the small performance degradation in the RW2 conductor that has been recently reported. [ABSTRACT FROM AUTHOR]

In this article, the analysis of mechanical energy changes in a gas medium flow with stable and variable density was presented. To determine the energy losses, the various sources of momentum and mass were used, which had an influence on air flow through the conduit in the system without heat exchange with the environment. The occurrence of varying density gas flow in the conduit (caused by local inflow of mass and momentum) in inclined pipes generates a natural depression–internal mechanical energy. The local momentum sources can facilitate or hinder the gas flow through the conduit. This phenomenon often appears in the network of underground mine workings and in ventilation and air conditioning installations. The characteristic for gas flow through a pipe or mining excavation is the equivalent aerodynamic resistance, the value of which is influenced by the mass and momentum of local sources. This value determines the facilitation or difficulty in gas transport through a section of conduit in relation to the mass stream of the medium. In this article, the dependency of mass flow and gas momentum with different densities on the value of the gas medium flow resistance in the conduit was analyzed. On the basis of the obtained results, the loss of mechanical energy and energy efficiency of flows were determined. In this work, two cases of fan work in suction and blowing modes were analyzed. For these examples, a gas inflow with three different mass streams, a density higher than the main stream density, and with a zero momentum value for this stream was modeled. Ten cases of mass inflow sources were considered. The results of the gas mass flow calculation through the fan m ˙ w and gas m ˙ 0 and the coefficient of transport efficiency are graphically presented in the paper. [ABSTRACT FROM AUTHOR]

Liquid metal can create a renewable protective surface on plasma facing components (PFC), with an additional advantage of deuterium pumping and the prospect of tritium extraction if liquid lithium (LL) is used and maintained below 450 °C, the temperature above which LL vapor pressure begins to contaminate the plasma. LM can also be utilized as an efficient coolant, driven by the Lorentz force created with the help of the magnetic field in fusion devices. Capillary porous systems can serve as a conduit of LM and simultaneously provide stabilization of the LM flow, protecting against spills into the plasma. Recently, a combination of a fast-flowing LM cooling system with a porous plasma facing wall (CPSF) was investigated [A. Khodak and R. Maingi, Nucl. Mater. Energy 26, 100935 (2021)]. The system takes an advantage of a magnetohydrodynamics velocity profile as well as attractive LM properties to promote efficient heat transfer from the plasma to the LL at low pumping energy cost, relative to the incident heat flux on the PFC. In the case of a disruption leading to excessive heat flux from the plasma to the LM PFCs, LL evaporation can stabilize the PFC surface temperature, due to high evaporation heat and apparent vapor shielding. The proposed CPSF was optimized analytically for the conditions of a fusion nuclear science facility [Kessel et al., Fusion Sci. Technol. 75, 886 (2019)]: 10 T toroidal field and 10 MW/m2 peak incident heat flux. Computational fluid dynamics analysis confirmed that a CPSF system with 2.5 mm square channels can pump enough LL so that no additional coolant is needed. [ABSTRACT FROM AUTHOR]

Ni-rich NCM materials have the high electrochemical capacities and low costs. However, the disadvantage of poor cycle performance severely limits their large-scale use. In this work, the nanoscale ion-electron mix-conductor Li 7.5 La 3 Zr 1.5 Co 0.5 O 12 was prepared by ball milling and used to directly mix LiNi 0.83 Co 0.11 Mn 0.06 O 2. After annealing, a mixed conductive protective layer could be formed on the surface of the NCM. The coating layer can protect the structural integrity of the NCM particles during cycling. At a current density of 1C between 2.8 and 4.5 V, the modified sample exhibited a capacity of 196 mAh g−1, and the capacity retention rate was as high as 85.7 % after 200 cycles, which was a significant improvement of 23.8 % over the pristine sample. The lithium-ion diffusion coefficient is enhanced and the charge transfer resistance is reduced by the mixed conductor cladding. The modified material shows an excellent rate performance. The specific capacity at 5C was 181 mAh g−1. The proposed modification method is simple in process and suitable for large-scale applications. The method has reference significance for the modification of other cathode materials. [ABSTRACT FROM AUTHOR]

Assessment of the pressure drop that occurs in cable-in-conduit conductors (CICCs) requires a reliable predictive model. In this paper, a fractal model to predict the pressure drop of helium flows in CICCs is proposed based on the porous media analogy and fractal theory. A fractal friction factor correlation is also derived using the proposed pressure drop model. The good agreement between the predictions and the experimental data for conductors with n 1 = 3 verifies the validity of both the fractal pressure drop model and the friction factor correlation for such configuration conductors. The fractal correlation indicates that the friction factor of the cable bundle in a CICC is related not only to the void fraction but also to the average hydraulic diameter, the tortuosity of the fluid flow paths, the maximum pore size and the fractal dimension of the cable cross-section. This theoretical correlation does not contain any fitting constants and each parameter has a clear physical meaning. [ABSTRACT FROM AUTHOR]

The impact of electromagnetic (EM) and thermal cyclic loading (referred as warm-up-cool-down—WUCD) on the Nb3Sn cable in conduit conductors for the toroidal field magnets of the ITER tokamak should be carefully assessed for the proper operation of the machine. The experience gained during the production phases of the TF conductors revealed that a degradation occurs when thermal and EM cyclic loading is applied at the nominal operating conditions of 10.78 T and 68 kA. Since at the beginning of the tokamak operation the nominal conditions will not be achieved, it is worth investigating to what extent lower EM loads affect the conductor performance, and the threshold of EM load that triggers the WUCD degradation. The aim of this investigation is to identify critical levels which determine the onset of this degradation, both in terms of thermal and EM cycles, and to study the performance of strands from different suppliers. For this assessment, a set of conductor samples were manufactured including all types of strands to be used in the TF coils of the ITER machine. These samples were subjected to a set of EM and thermal cycles representing in a realistic way the actual operation of the conductors in the ITER machine. The tests were performed in the SULTAN facility of the Swiss Plasma Center at working conditions ranging from 5.4 T–34 kA to 10.78 T–68 kA. This work presents the results obtained in these tests in terms of current sharing temperature (Tcs), effective strain, rate of degradation at different working conditions and their implications for the prospected conductor performance in the machine. [ABSTRACT FROM AUTHOR]

In the material of xLi 2 MnO 3 ·(1-x) LiMO 2 (0 < x < 1), the Li 2 MnO 3 component is used to stabilize the layered LiMO 2 structure. However, the electrochemical inactive Li 2 MnO 3 makes Li-ion diffusion difficult, leading to a sluggish rate capability. In this work, Li 1.3 Ti 1.7 Al 0.3 (PO 4) 3 (LTA0.3), a NASICON-type Li-ion conductor, is applied to modified Li 1.2 Mn 0.54 Ni 0.13 Co 0.13 O 2 to overcome the above shortcoming. Additionally, the Li-ion conductivity of LiTi 2 (PO 4) 3 can be improved effectively by replacing tetravalent cation Ti4+ with trivalent Al3+ at the optimal ratio. At 1C rate, the LR cathode with 3 wt% LTA0.3 delivers 200 mAh g−1 after 170 cycles and maintains 140 mAh g−1 after 500 cycles. Moreover, the modified cathode shows an enhanced rate performance of 169.7 mAh g−1 at 5C. Enhanced cycle durability and rate capability are aroused by the 3D skeletal framework of LTA0.3, which is suitable for Li-ion diffusion. The LTA0.3 coating layer displays a robust shell which not only avoids the corrosion of electrode materials but also effectively facilitates Li-ion diffusion. [ABSTRACT FROM AUTHOR]

In this paper, we develop a partitioned scheme with multiple-time-step technique for the nonstationary dual-porosity-Stokes model. The proposed partitioned scheme allows different time steps in the different subdomains of the dual-porosity-Stokes model: conduits/macrofractures, microfractures, and matrix. Under a time step restriction which depends on the physical parameters of the model, we derived the stability of the partitioned scheme. The error estimates of this scheme are also provided. The numerical experiments confirm the theoretical analysis and demonstrate the proposed scheme is reliable, applicable, and consumes less CPU time. [ABSTRACT FROM AUTHOR]

High Temperature Superconductors (HTS) are promising materials for future fusion magnets. One of HTS conductors' main issues is the quench protection: the quench develops much slower than in LTS, delaying the quench detection by voltage monitoring and causing a massive temperature increase before detection. The Swiss Plasma Center (SPC), with the support of EUROFusion, has upgraded the SULTAN facility to test large current conductors during the whole quench evolution. The 100 kA superconducting transformer has been replaced by an 18 kA direct power supply, which allows sustaining the operating current in the sample during a quench. Five HTS conductors have been manufactured at SPC: they are sub-size of the HTS high-current cables designed by the group for an HTS high current high field cable proposed for EU-DEMO Central Solenoid (CS) hybrid magnet. Every conductor has a specific feature. The aim is to compare the quench behavior of the five conductors “parametrically”. The commissioning of the upgraded facility and the preliminary results of the measurements are presented in this work. [ABSTRACT FROM AUTHOR]

Vortex drop structure is used to convey water through underground conduits in urban sewers and drainage systems. During the plunge, a large volume of air is entrained into the water and then is released from the drop shaft downstream. Basically, volume of entrained air is comparatively hard to measure. In this research, a physical model was constructed to understand the mechanism of air circulation through vortex structure. In fact, experiments were tested to investigate effects of variables on the air circulation. Through the experiments, results of dimensional analysis results indicated that the approach flow Froude number (Fr), drop total height to shaft diameter ratio (L/D), and sump depth to shaft diameter ratio (Hs/D) had significant influences on the relative air discharge (β). To express the role of each independent variable on relative air discharge (β) in terms of regression analysis, response surface methodology, based on central composite face-entered design (RSM-CCFD) was examined. Hence, a regression-based-equation in form of quadratic polynomial was proposed to estimate β variable. Additionally, experimental design was to investigate simultaneous effects of Fr , L/D , and Hs/D on the β. Results of experimental study indicated that β variable had upward trends with an increase in Fr variable and L/D ratio. Analysis of variance for the proposed regression model demonstrated that simultaneous effect of L/D and Hs/D on β variable remained statistically significant, whereas other interaction effects of variables were insignificant. Ultimately, the optimum location for installation of air vent pipe ranged from D to 2.25D in a way that air vent pipe had the most satisfying level of air outlet flow performance. [ABSTRACT FROM AUTHOR]

Embolism spreading in dehydrating angiosperm xylem is driven by gas movement between embolized and sap‐filled conduits. Here we examine how the proximity to pre‐existing embolism and hydraulic segmentation affect embolism propagation. Based on the optical method, we compare xylem embolism resistance between detached leaves and leaves attached to branches, and between intact leaves and leaves with cut minor veins, for six species. Embolism resistance of detached leaves was significantly lower than that of leaves attached to stems, except for two species, with all vessels ending in their petioles. Cutting of minor veins showed limited embolism spreading in minor veins near the cuts prior to major veins. Moreover, despite strong agreement in the overall embolism resistance of detached leaves between the optical and pneumatic method, minor differences were observed during early stages of embolism formation. We conclude that embolism resistance may represent a relative trait due to an open‐xylem artefact, with embolism spreading possibly affected by the proximity and connectivity to pre‐existing embolism as a gas source, while hydraulic segmentation prevents such artefact. Since embolism formation may not rely on a certain pressure difference threshold between functional and embolized conduits, we speculate that embolism is facilitated by pressure‐driven gas diffusion across pit membranes. Application of the optical and pneumatic method shows that embolism spreading across xylem conduits may occur under different water potentials, depending on the proximity and interconduit connectivity to pre‐existing embolism. Hydraulic segmentation, however, may reduce this artefact considerably. [ABSTRACT FROM AUTHOR]

Poly(L-lactide (PLLA), nano-hydroxyapatite (nHA) and multi-walled carbon nanotube (MWCNTs) biodegradable scaffolds were produced through thermally induced phase separation (TIPS) and ultrasonically dispersed for use in tissue engineering. The results obtained showed that mechanical properties and conductivity improved with respect to the PLLA to which nanotubes had been added. Scaffolds with a nanotube weight of 1% and 5% showed the best properties, with a very uniform and well-arranged structure. The weight percentage of nanotubes is an essential parameter in determining the formation of agglomerates. Samples with a 10% carbon nanotube (CNT) weight showed aggregates, with the TIPS and ultra-sonication techniques found to be unsuitable for production with such high levels of reinforcement. The degradation process was modulated by morphology and not crystallinity, with the PLLA/nHA samples degrading more readily due to their smaller pores which did not allow degradation products to escape as easily, resulting in autocatalytic degradation. The addition of nanotubes had a significant impact on the dielectric properties of the samples, which ceased to be an insulator and became a conductor. [ABSTRACT FROM AUTHOR]

Nanohybridization of carbon nanotubes (CNTs) and Cu is a promising strategy to enhance the electrical performance of CNT films or fibers for applications in electromagnetic shielding and for further uses as conductors. However, overcoming the hydrophobic characteristics of CNTs is one of the most appropriate problem faced during the fabrication of hybrid materials with foreign materials. In this study, we report a fabrication method for highly conductive long multiwalled CNTs (LMWCNTs)/Cu hybrid films based on electroplating. The wettability of the Cu plating solution and the electrical conductivity of the LMWCNT films were rationally controlled by thermal deoxygenation in air at temperatures below 200 °C. The thermal modification provides a highly conductive and hydrophilic surface on the CNT structure; these physical changes eventually enable uniform Cu electrodeposition in an aqueous electrolyte. The periodic morphological, electrochemical, electrical, and crystallographic analyses indicate that Cu nucleated from the inside of the CNT film during the initial stage of electrodeposition; further, the Cu nuclei subsequently grew on the CNT surface, resulting in a densely packed CNT-Cu composite. Highly conductive long multiwalled CNTs (LMWCNTs)/Cu hybrid films are fabricated by electroplating, which was rationally controlled by modulating the wettability of the Cu precursor solution on the oxidized LMWCNT films by deoxygenation in air at 150 °C. Image 1 • Thermal deoxygenation alters electrical and surface properties of Ox-LMWCNT for electroplating. • Cu nucleates on the inner and outer surface of the CNT films during electrodeposition. • Cu is electroplated uniformly with high electrical conductivity through the CNT film. • CNT-Cu is nanohybridized by electrodeposition in an aqueous system. [ABSTRACT FROM AUTHOR]

166.6-MHz superconducting cavities have been chosen for the High Energy Photon Source (HEPS) as the main accelerating structures to provide 900 kW of beam power and 5.4 MV of accelerating voltage. A proof-of-principle cavity adopting the quarter-wave beta = 1 geometry was previously developed. Excellent performance was achieved in vertical tests at cryogenic temperatures. The cavity was later welded with a helium jacket, dressed with a power coupler and other ancillaries, and high-power tested in a test cryomodule. Performance degradation was observed and analyzed. Evidence from temperature sensor readout and heat loss measurement results suggested an overheating in the cavity–coupler interface region causing a "thermal runaway" and eventually quenching the cavity at its design voltage. Electromagnetic-fluid-thermal coupled simulation has thus been conducted, and the hypothesis was nicely validated. Finally, solutions were proposed including an elongated niobium extension tube at the coupler port and an optimized helium gas cooling of the power coupler's outer conductor. These modifications have been subsequently applied on the 166.6-MHz higher-order-mode damped superconducting cavities for the HEPS. Heat loss at 4.2 K contributed by the power coupler can be largely reduced with a modest gas cooling scheme. Similar design approaches can also be applied to other non-elliptical superconducting structures with on-cavity high-power coupler mountings. [ABSTRACT FROM AUTHOR]

The integration of fluctuating renewable sources, load growth and aging of the current power system is the major reasons for the development of the electric power engineering. Transmission lines are recently facing new technical and economic challenges. The immediate utilization of advanced technologies and modern methods could solve these issues. This study deals with the transmission and distribution of electrical energy with orientation on the calculation of operating temperature on the conductor of transmission line, which is under actual current load. The load of the transmission line is limited with allowable operating temperature. The operating temperature should not exceed the allowable operating temperature because the conductors of the transmission line have mechanical limit from the standpoint of deflection of conductors. The operating temperature as well as operating conditions of the conductor is determined by the type and material of the ACSR conductor. This article aims to propose the suitable calculation methods of the operating temperature of the overhead transmission line conductor in real operating conditions (external weather influences, current loading and corona effect). The originality of this proposed method (by differential equation) lies in considering corona effect. This improves the accuracy of the calculation of the operating temperature of the conductor under real conditions. In this article, the calculations are compared according to methodology of differential equation and methodology described in CIGRE Technical Brochure 601—guide for thermal rating calculations of overhead lines. The methodology of differential equation counts with or without losses by corona. The article also compares these methods of operating temperature during days in various different weather conditions like environment temperature, solar irradiance, wind speed and direction. It was found that under the action of the corona, the temperature of the conductor increases to a small extent. [ABSTRACT FROM AUTHOR]

This review focuses on investigations of groundwater flow and solute transport in karst aquifers through laboratory scale models (LSMs). In particular, LSMs have been used to generate new data under different hydraulic and contaminant transport conditions, testing of new approaches for site characterization, and providing new insights into flow and transport processes through complex karst aquifers. Due to the increasing need for LSMs to investigate a wide range of issues, associated with flow and solute migration karst aquifers this review attempts to classify, and introduce a framework for constructing a karst aquifer physical model that is more representative of field conditions. The LSMs are categorized into four groups: sand box, rock block, pipe/fracture network, and pipe‐matrix coupling. These groups are compared and their advantages and disadvantages highlighted. The capabilities of such models have been extensively improved by new developments in experimental methods and measurement devices. Newer technologies such as 3D printing, computed tomography scanning, X‐rays, nuclear magnetic resonance, novel geophysical techniques, and use of nanomaterials allow for greater flexibilities in conducting experiments. In order for LSMs to be representative of karst aquifers, a few requirements are introduced: (1) the ability to simulate heterogeneous distributions of karst hydraulic parameters, (2) establish Darcian and non‐Darcian flow regimes and exchange between the matrix and conduits, (3) placement of adequate sampling points and intervals, and (4) achieving some degree of geometric, kinematic, and dynamic similitude to represent field conditions. [ABSTRACT FROM AUTHOR]

Li 2 O-2B 2 O 3 coated Li 4 Ti 5 O 12 anode with protected particle surface and fast ion transfer exhibit desired rate capability and cycling stability for lithium ion batteries. Li 2 O-2B 2 O 3 (LBO) ionic conductor with high conductivity plays an important role in boosting the rate performance and cycling stability of Li 4 Ti 5 O 12 (LTO) anode for lithium-ion batteries by preventing direct exposure of LTO to the electrolyte. Herein, the effect of LBO coating layer on lithium ion (Li+) storage performance is investigated in detail by adjusting the adding amount of LBO precursor dispersion. LTO coated with 2 wt% LBO achieves an optimum performance with a specific capacity of 172.9 mA h g−1 at a current density of 0.1 A g−1, an improved rate capability (specific capacity of 127.9 mA h g−1 is maintained when the current density is 20 times than 0.1 A g−1) and a remarkable cycling stability (capacity retention of 94.2% after 4000 cycles at 2.0 A g−1). These LBO-LTO composites are competitive and promising candidates for electrochemical energy storage and other applications. [ABSTRACT FROM AUTHOR]

Thermal energy storage systems are used mainly in buildings and industrial processes. In this study, solar energy storage by using a circular conduit filled with porous media that is saturated by a non-Newtonian fluid at constant heat flux was represented. The fully developed region was studied by solving the equations analytically, the non- Newtonian fluid parameters used in this model are carboxymethyl cellulose (CMC) properties. In addition, graphite was used as porous media. The heat flux data for Amman city was used in the equations in this study. The effect of Porosity and particle diameter and pressure on the performance of the model were discussed and sketched. As a result, the temperature of storage filled with CMC fluid is better than water in porous media. It is found that the power index of the fluid, porosity, particle diameter, pressure drop, and conduit radius effect inversely the temperature in energy storage. In January, the temperature variation in conduit at the same conditions reach for CMC-1 to 35°C for n = 0.724 and to 85°C for n = 0.7182 and to 190°C for n = 0.7122. CMC-2 has a higher consistency index at the same concentration which means higher viscosity and less power index than CMC-1 so the temperature variation in conduit reaches 50°C for n = 0.599 and 200°C for n = 0.57. The stored energy of CMC-1 for n = 0.724, n = 0.7182, and n = 0.7122 is approximately 120 kJ, 300 kJ, and more than 600 kJ respectively, and the stored energy of CMC-2 n = 0.599 and n = 0.57 is 200 kJ and approach to 800 kJ at the same conditions and conduit. [ABSTRACT FROM AUTHOR]

Despite the common occurrence of heterogeneous andesitic eruptions, few studies have investigated the compositional effects on microlite crystallization and vesiculation in co-erupted natural samples. In 2006, Augustine Volcano erupted compositionally heterogeneous andesites that range from 56.4 to 63.3 wt% SiO2 and include two endmember lithologic groups: low-silica andesite (LSA) and high-silica andesite (HSA). Textural and compositional differences between LSA and HSA end members are explored for two discrete, sequential vulcanian explosions from January 17 (event 9) and 27 (event 10), 2006. Groundmass glass compositions of pyroclasts within LSA and HSA compositional suites are not colinear and do not correlate with plagioclase microlite crystallinities, indicating eruption from multiple isolated shallow magma reservoirs with various pressure-temperature pathways. HSA pyroclasts have lower crystallinities, 0.02–0.24, than most LSA pyroclasts, 0.16–0.39, demonstrating the influence of composition on crystallinity. Additionally, microlite textural and groundmass glass compositional differences exist between consecutive vulcanian explosions. The event 9 deposits have a typical bimodal density distribution and groundmass glass compositions range from 65 to 78 wt% SiO2. Plagioclase microlite number densities (MNV) are 104.6–6.4 mm−3 and crystallinities are 0.02 to 0.28, similar to products from other andesitic vulcanian eruptions. Deposits from the early phase of event 10 have a bimodal density distribution and contain a high proportion of LSA pyroclasts, similar to event 9. Groundmass glass compositions range from 72 to 79 wt% SiO2 and plagioclase MNV are 105.9–6.3 mm−3, forming narrower ranges compared to event 9. A transition occurred during the later phase of event 10 to a unimodal density distribution, a more homogeneous groundmass glass composition, 75–78 wt% SiO2, a higher proportion of HSA pyroclasts, and the highest MNV of 105.9–6.7 mm−3. We interpret this shift to reflect eruption from reservoir depths around 4–6 km and the cessation of pre-eruptive magma staging in the upper conduit, transitioning the eruption to continuous and effusive phases. Attention to heterogeneous andesitic erupted products reveals additional details about heterogeneous shallow magma storage, variable upper conduit magma staging, and a range of pressure-temperature paths prior to fragmentation. [ABSTRACT FROM AUTHOR]

The second-generation high-temperature superconducting tapes (2G-HTS) such as the REBCO coated conductors are known for their strong mechanical properties and high current carrying capacity with low ac losses compared with first-generation HTS tapes as well as low-temperature superconductors. Therefore, they seem to be good candidates to assemble coils for superconducting rotating electric machines (SuREMs). In this article, to investigate the influence of a soft magnetic composite (SMC) material on the dc and ac HTS coil performances at cryogenic temperatures, GdBCO- and YBCO-based commercial tapes from different manufactures were used to assemble ten HTS coils in double-pancake configuration. These tapes were wound using two different core structures, i.e., fixed and movable cores, having the same circular shape but different diameters as well as materials, i.e., fiberglass and SMC. Critical currents and ac transport current losses of these coils were measured using the electrical method. To evaluate the parallel and perpendicular components of the profile of magnetic flux density for each assembled HTS coil, a finite element model has been developed using Maxwell 2D. Eventually, the performance of different coils for SuREM application was discussed. [ABSTRACT FROM AUTHOR]

Conductive polymer composites (CPCs) are vital and indispensable for the emerging field of soft electronics. In this work, a new strategy for using carbon nanotubes (CNTs)/carbon nanofibers (CNFs) and liquid metal droplets as multiphase hybrid fillers for CPCs is presented. We found that CPCs with multiphase hybrid conductive fillers had advantages in electromechanical properties over those with single solid-phase conductive fillers. CNTs/CNFs can easily form conductive paths in the polymer due to their excellent electrical conductivity with large aspect ratio. Self-repair of conductive networks was realized since the exposed Galinstan under strains could bridge the gap between CNTs/CNFs to form new conductive pathways. In addition, the influences of the size and content of conductive fillers on the electromechanical properties of CPCs were investigated. We found CPCs with liquid metals can be served as a flexible strain sensor under mild strain, while as a conductor under large strain due to the robust stability of resistance, which has not been reported yet in the literature. The CPCs presented in this work could provide potential applications in wearable electronics and flexible electronics. [ABSTRACT FROM AUTHOR]

All‐solid‐state sodium‐ion batteries are highly promising for next generation grid energy storage with improved safety. Among the known sodium superionic conductors, the Na3PnS4 family and the recently discovered Na11Sn2PnS12 (Pn = P, Sb) have garnered major interest due to their extremely high ionic conductivities. In this work, comprehensive investigation of the Na3PnS4‐Na4TtS4 (Pn = P/As/Sb, Tt = Si/Ge/Sn) phase space of superionic conductors using density functional theory calculations, as well as AIMD simulations on the promising new Na11Sn2PnS12 (Pn=P/As/Sb) structures are presented. Crucial design rules on the effect of cation mixing are extracted on relative phase stability, electrochemical stability, moisture stability, and ionic conductivity. In particular, it is shown that while larger cations can substantially improve the ionic conductivity and moisture stability in these structures, there is an inherent trade‐off in terms of electrochemical stability. Na11Sn2AsS12 is also identified as a hitherto unexplored stable sodium superionic conductor with higher Na+ conductivity and better moisture stability than the Na11Sn2PS12 and Na11Sn2SbS12 phases already reported experimentally. [ABSTRACT FROM AUTHOR]

The impact melt‐bearing breccias at the Ries impact structure, Germany, host degassing pipes: vertical structures that are inferred to represent conduits along which gases and fluids escaped to the surface, consistent with hydrothermal activity that occurs soon after an impact event. Although the presence of degassing pipes has been recognized within the well‐preserved and long‐studied ejecta deposits at the Ries, a detailed mineralogical study of their alteration mineralogy, as an avenue to elucidate their origins, has not been conducted to date. Through the application of high‐resolution in situ reflectance imaging spectroscopy and X‐ray diffraction, this study shows for the first time that the degassing pipe interiors and associated alteration are comprised of hydrated and hydroxylated silicates (i.e., Fe/Mg smectitic clay minerals with chloritic or other hydroxy‐interlayered material) as secondary hydrothermal mineral phases. This study spatially extends the known effects of impact hydrothermal activity into the ejecta deposits, beyond the crater rim. It has been suggested that the degassing pipes at the Ries are analogous to crater‐related pit clusters observed in impact melt‐bearing deposits on Mars, Ceres, and Vesta. The results of this work may inform on the presence of crustal volatiles and their interaction during the impact process on rocky bodies throughout the solar system. The Mars 2020 Perseverance rover may have the opportunity to investigate impact‐related features in situ; if so, this work suggests that such investigations may provide key information on the origin and formation of clay minerals on Mars as well as hold exciting implications for future Mars exploration. [ABSTRACT FROM AUTHOR]

Although the involvement of hydrous fluids has been widely invoked in formation of podiform chromitites in ophiolites, there is lack of natural evidence to signify the role and mechanism of fluids. In this study, a new model for the genesis of podiform chromitite is proposed on basis of revisits of comprehensive petrological, mineralogical and geochemical results of the well-preserved Kızıldağ ophiolite and the well-characterized Luobusa chromite deposit. In this model, ascending magmas intruding oceanic lithospheric mantle would presumably form a series of small magma chambers continuously connected by conduits. Tiny chromite nuclei would collect fluids dispersed in such magmas to form nascent droplets. They tend to float upward in the magma chamber and would be easily transported upward by flowing magmas. Chromite-rich droplets would be enlarged via coalescence of dispersed droplets during mingling and circulation in the magma chamber and/or transport in magma conduits. Crystallization of the chromite-rich liquid droplets would proceed from the margin of the droplet inward, leaving liquid entrapped within grains as precursor of mineral inclusions. With preferential upward transportation, immiscible chromite-rich liquids would coalesce to a large pool in a magma chamber. Large volumes of chromite would crystallize in situ, forming podiform chromitite and resulting in fluid enrichment in the chamber. The fluids would penetrate and compositionally modify ambient dunite and harzburgite, leading to significant fractionations of elemental and isotopic compositions between melts and fluids from which dunite and chromitite respectively formed. Therefore, fluid immiscibility during basaltic magma ascent plays a vital role in chromitite formation. [ABSTRACT FROM AUTHOR]

Tunnel magnetoresistance (TMR), thermal stability, and critical switching current are important metrics of a magnetic tunnel junction (MTJ). In this work, a detailed study of these metrics is conducted for the down-scaling of the transverse dimensions of the MTJ. The quantum transport and the magnetization dynamics simulations are performed using non-equilibrium Green’s function in the mode-space approach and object-oriented micromagnetic framework (OOMMF), respectively. The study of areal size quantization effects on the TMR shows that most of the contribution to the TMR comes from lower energy sub-bands and that the TMR saturates for dimensions above 50 nm. An anomalous behavior is observed in the bias dependence of TMR for the lower energy sub-bands and is explained in terms of the modified Slonczewski’s analytical model for conductance around zero bias. The study of TMR scaling is extended to consider non-idealities by introducing elastic dephasing into our simulations. It is shown that with down-scaling of diameters, dephasing affects the zero bias TMR predominantly below 20 nm. Furthermore, TMR is also studied in terms of sensitivity to the variations in the interface layer and the asymmetric reduction of TMR with bias and its reversal at higher bias is observed. OOMMF simulations of the larger stack, including the free layer, are carried out to understand the qualitative link between magnet switching behavior, thermal stability, and critical current density with area scaling. It is shown that the area dependence of thermal stability and critical current follows each other qualitatively and the scaling of both these metrics is correlated with different regimes of magnetization switching, such as macrospin behavior or formation of metastable complex textures. The implications of scaling, on the various MTJ metrics, are discussed in terms of the application domain. [ABSTRACT FROM AUTHOR]

This article utilizes conductors with insulation of high thermal conductivity (ThC) combining suitable cooling methods to enhance the performance of traction motors for electric vehicles. The performance of a 10 kW interior permanent magnet (IPM) motor without forced cooling is considered as a benchmark. Then, the conductors with two conventional insulation materials and two with high ThC are applied to the IPM motor windings. Two cooling methods, finned housing (no forced cooling) and water cooling, are considered here. It is found that using conductors with high ThC insulation without forced cooling can only cool the windings by several degrees; however, the temperature can be considerably reduced by combining water cooling with an appropriate flow rate. The torque and power output of the IPM motor can also be significantly improved. This indicates that forced cooling can further enhance the effectiveness of conductors with insulation of high ThC. Two induction motors using conductors with two different insulation materials (0.1 and 3 W/ $\text{m}\cdot \text{K}$) are tested. The experimental results validate the analysis. [ABSTRACT FROM AUTHOR]

• Forced-flow cooling with helium gas is required for HTS fusion magnets at 20–30 K. • Temperature distribution is calculated with thermal interaction between conductors. • There exists an internal peak temperature, which may well be predicted by NTU. • Thermal insulation in axial contact can significantly improve cryogenic stability. A key design feature is presented to improve the cryogenic stability of forced-flow gas-cooled HTS conductors for fusion magnets. In order to realize the compact and economic fusion system, a variety of conductors are under development with stacked REBCO tapes so that the high-field magnets can operate at 20–30 K with the internal flow of helium gas. Thermal-hydraulic analysis is typically based on 1-D models under a prescribed thermal load along the conductors. In this study, the effect of thermal interaction between adjacent conductors in a winding pack is rigorously considered for the analysis. In a double pancake with single cooling loop, it is evidently verified that the conductor temperature may rise to a peak at inner layers, seriously affecting current sharing and thermal stability. The analytical results are useful in predicting the temperature and location of hot spot in terms of a dimensionless parameter, NTU. In theory, the gas-cooled magnet can be thermally stable by either infinitely increasing or infinitesimally decreasing the thermal interaction between conductors. In practice, however, the thermal insulation to minimize the contact between inbound and outbound flows in a double pancake is proposed as an effective way to improve the cryogenic stability. [ABSTRACT FROM AUTHOR]

LiCoO 2 has excellent volume energy density, and is the dominant cathode materials for 3 C electronic products. However, the capacity of LiCoO 2 is not fully utilized, and its cycle stability is not high enough. To preserve the structural stability of LiCoO 2 at high voltage, the mixed ion-electron conductor Li 0.33 La 0.557 Ti 0.8 Cr 0.2 O 3 is coated on LiCoO 2 particles, and the effects of coating amount and annealing temperature on the electrochemical performances are systematically investigated. The capacity retention of the pristine LiCoO 2 in the range of 2.8–4.5 V is only 51.0% after 200 cycles, which is related to the resistance increase of interface and cracks of cathode particles. The coating layer can improve the interface stability and keep the particles intact, and therefore, the capacity retention of the coated sample is significantly increased to 88.2%. • Mixed electron-ion conductor Li 0.33 La 0.557 Ti 0.8 Cr 0.2 O 3 is chosen as coating layer of LiCoO 2. • The coating material is coated on LiCO 2 particles by coprecipitation method. • The hard shell can maintain the particle integrity of LiCoO 2. • The coated particles have excellent cycle stability and rate performance. [ABSTRACT FROM AUTHOR]

Low-pressure silica polymorphs, e.g. quartz (Qtz), tridymite (Trd), and cristobalite (Crs), are common in silicic magmas, but the conditions of their formation are still unclear. The stability fields of these polymorphs have been determined in the SiO2, SiO2–H2O, and haplogranite systems, but these simple systems are not directly applicable to silica polymorph crystallization in natural silicic magmas. The present study compiles an experimental database of new and previously-published data documenting the crystallization of silica phases in natural silicic magmas and simple synthetic systems. Silica polymorphs are identified using Raman spectroscopy and their pressure-temperature domains of occurrence and chemical compositions are determined at pressures between 0·1 and 200 MPa, temperatures between 685 to 1200° C, and under H2O-saturated and H2O-undersaturated conditions.   Qtz is the stable silica polymorph at pressures higher than 25–30 MPa, temperatures between ∼700 and 950° C, and occurs for a narrow range of melt SiO2 contents (∼79–81 wt %). Constraints on Qtz stability derived from simple systems are mutually compatible with, and thus applicable to natural compositions. This is consistent with Qtz compositions being close to 'pure' SiO2, both in experiments and nature. In volcanic systems, Qtz crystallization may occur in magmatic reservoirs and deep volcanic conduits.   Trd did not crystallize in the experiments conducted as part of this study despite several experiments having been performed in the Trd stability field. This is consistent with results from the literature which show that Trd crystallization is kinetically inhibited in particular relative to Crs. Natural Trd have compositions deviating substantially from 'pure' SiO2, so that stability limits determined in simple systems should not be applied directly to natural cases.   Crs was encountered at pressures below 20–30 MPa (or H2O contents < ∼1·5 wt %), from sub-solidus (∼800° C) to near-liquidus (up to 1040° C), and coexisting with melts having a large range of SiO2 contents (70–81 wt %). The Crs stability field is much larger in natural magmas compared to pure SiO2 systems. Crs is a metastable phase stabilized by components (Al, Na, K; about 3 wt %) present in the silicic melt. In volcanic systems, Crs crystallization may thus be restricted to subsurface manifestations such as lava domes. [ABSTRACT FROM AUTHOR]

This paper presents an immersed phase field model designed to predict the fracture-induced flow due to brittle fracture in vuggy porous media. Due to the multiscale nature of pores in the vuggy porous material, crack growth may connect previously isolated pores, which leads to flow conduits. This mechanism has important implications for many applications such as disposal of carbon dioxide and radioactive materials and hydraulic fracture and mining. To understand the detailed microporomechanics that causes the fracture-induced flow, we introduce a new phase field fracture framework where the phase field is not only used as an indicator function for damage of the solid skeleton but also used as an indicator of the pore space. By coupling the Stokes equation that governs the fluid transport in the voids, cavities, and cracks and Darcy's flow in the deformable porous media, our proposed model enables us to capture the fluid–solid interaction of the pore fluid and solid constituents during crack growth. Numerical experiments are conducted to analyze how the presence of cavities affects the accuracy of predictions based on the homogenized effective medium during crack growth. [ABSTRACT FROM AUTHOR]

This study aims to characterize the effect of inflow pulsatility on the hydrodynamic power loss inside intersecting double-inlet, double-outlet pipe intersection (DIPI) with cross-flow mixing. An extensive set of computational fluid dynamics (CFD) simulations was performed in order to identify the individual effects of flow pulsatility parameters, i.e., amplitude, frequency, and relative phase shift between the inflow waveform oscillations, on power loss. An experimentally validated second order accurate solver is employed in this study. To predict the pulsatile flow performance of any given arbitrary inflow waveforms, we proposed three easy-to-calculate pulsatility indices. The frequency-coupled quasi-steady flow theory is incorporated to identify the functional form of pulsatile power loss as a function of these indices. Our results indicated that the power loss within the inflow branch sections, lumped outflow-junction section, and the whole conduit correlates strongly with the pulsatility of each inflow waveform, the total inflow pulsatility, and inflow frequency content, respectively. The complete CFD simulation matrix provided a unified analytical expression that predicts pulsatile power loss inside a one-degree offset DIPI geometry. The predictive accuracy of this expression is evaluated in comparison to the CFD evaluation of arbitrary multi-harmonic inflow waveforms. These results have important implications on hydrodynamic pipe networks that employ complex junctions as well as in the patient-to-patient comparison of surgically created vascular connections. Coupling the present analytical pulsatile power loss expression with non-dimensional steady power loss formulation provided a valuable predictive tool to estimate the pulsatile energy dissipation for any arbitrary junction geometry with minimum use of the costly CFD computations. [ABSTRACT FROM AUTHOR]