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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]

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]

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]

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]

In this study, a bio-composite conduit containing nano bioglass/gelatin/nanosilver particles (nBG/Gel/nAg) was developed by freeze-drying technique, for peripheral nerve regeneration. The present study aimed to develop nBG/Gel conduits enhanced with nanosilver to connect the two separated neural ends for peripheral nerve regeneration and decrease of the infection risk in particular with resistant nosocomial stains. First, the BG nanoparticles were synthesised via sol–gel method and characterised using transmission electron microscopy, X-ray diffraction analysis and Fourier transform infrared spectroscopy. The surface morphology and pore size of the nanocomposite were investigated through scanning electron microscopy and EDX analysis was used to determine the amount of energy for each element available in the conduit. Antibacterial properties were determined by (S. aureus) gram-positive and (E. coli) gram-negative bacterial strains by soaking the conduits in 2 × 10−4 µL to 9 × 10−4 µL of the colloidal nanosilver solution. Biocompatibility was assessed by MTT assay, which showed that nanosilver toxicity of all concentrations is not significant compared to the control. According to the results, 7 × 10−4 µL AgNs had the lowest cytotoxicity effect and the most antibacterial activity. Thus, these results suggest that nBG/Gel/nAg conduits have the potential of controlling scaffold-associated bacterial infection during nerve regeneration. [ABSTRACT FROM AUTHOR]

This paper presents a novel numerical approach to simulate H-plane rectangular-waveguide microwave circuits considering a reduced quasi-2D simulation domain with benefits for computational cost and time. With the aim to evaluate the attenuation of the full height 3D component, we propose a modified expression for the waveguide top/bottom wall conductivity. Numerical 2D simulations are validated against results from full wave 3-D commercial electromagnetic simulator. After a benchmark on a simple straight waveguide model, the method has been successfully applied to an asymmetric un-balanced power splitter, where an accurate power loss prediction is mandatory. Simulation time and memory consumption can be reduced by a factor ten and seven respectively, in comparison with complete 3D geometries. Finally, we show that, also for quasi-2D E-bend waveguide, a case where the translational H-plane symmetry is broken, the error on conductor losses computation is mitigated by our approach since the method remains still valid in a first approximation. [ABSTRACT FROM AUTHOR]

We report measurements of the splay and bend elastic constants of 4′-butyl-4-heptyl-bicyclohexyl-4-carbononitrile (CCN47). We find K11 to be largely constant across the nematic range, with a value of ∼10 pN. K33 has a slightly lower value with K33/K11 ∼ 0.9 pN far from the transition to the SmA. In the vicinity of the SmA phase, K33 diverges with critical exponent γ = –0.6, with K33/K11 exceeding 5 close to the transition. [ABSTRACT FROM AUTHOR]