Twisted Pair Research Articles

Enhanced Biocidal Activity of Heterophase Zinc Oxide/Silver Nanoparticles Contained within Painted Surfaces

Today, one of the biggest challenges is infections in the painted walls of hospitals. Acrylic-based paints are a target of antibiotic-resistant microorganisms since they contain cellulosic compounds as thickeners. The aim of this study was to synthesize and investigate the biocidal activity and toxicity of heterophase ZnO-Ag nanoparticles fixed in water-based acrylic paint layers in reference to a nontreated water-based paint. The ZnO-Ag nanoparticles with average particle sizes of about 80 nm were simply obtained by electrical explosion of two twisted wires in an oxygen-containing atmosphere. The nanoparticles and modified paint were characterized using SEM, TEM, XPS, and XRD techniques. The antimicrobial activity of the nanoparticles and modified paint layers was tested against P. aeruginosa, S. aureus, MRSA, E. coli bacteria, and C. albicans using ISO 22196. The antiviral activity against smallpox virus was tested according to ISO 21702. Flow cytometry tests were used to investigate the toxicity of the modified paint coating. As-synthesized nanoparticles had “Janus-like” morphology, with a clear interface inside the nanoparticle. Nanoparticles had enhanced antibacterial activity, which is based on the nanoparticle photocatalytic activity in water decomposition and reactive oxygen species generation. The paint coating with a ZnO-Ag nanoparticle mass ratio of 1.0 wt.% displayed significant antibacterial activity (more than a 99% reduction) and 100% antifungal activity. In addition, this coating inactivates >99% of the virus after 2 h of contact relative to a nontreated control paint. The paint coating showed low toxicity against the sensitive 3T3 fibroblast cell line. More than 90% cell viability was observed after 24 h of incubation with the sample extract. Therefore, heterophase ZnO-Ag nanoparticles have high biocidal activity and low toxicity use and can be applied to other commercial water-based paints to improve their performance against pathogens.

Measuring residual stresses in individual on-chip interconnects using synchrotron nanodiffraction

As the dimensions of interconnects in integrated circuits continue to shrink, an urgent need arises to understand the physical mechanism associated with electromigration. Using x-ray nanodiffraction, we analyzed the stresses in Blech-structured pure Cu lines subjected to different electromigration conditions. The results suggest that the measured residual stresses in the early stages of electromigration are related to relaxation of stresses caused by thermal expansion mismatch, while a developing current-induced stress leads to reductions in the residual stress after longer test times. These findings not only validate the feasibility of measuring stress in copper lines using nanodiffraction but also highlight the need for a further understanding, particularly through in situ electromigration experiments with x-ray nanodiffraction analysis.

Twisted pair transmission line coil – a flexible, self-decoupled and robust element for 7 T MRI

ObjectiveThis study evaluates the performance of a twisted pair transmission line coil as a transceive element for 7 T MRI in terms of physical flexibility, robustness to shape deformations, and interelement decoupling. MethodsEach coil element was created by shaping a twisted pair of wires into a circle. One wire was interrupted at the top, while the other was interrupted at the bottom, and connected to the matching circuit. Electromagnetic simulations were conducted to determine the optimal number of twists per length (in terms of B₁+ field efficiency, SAR efficiency, sensitivity to elongation, and interelement decoupling properties) and for investigating the fundamental operational principle of the coil through fields streamline visualisation. A comparison between the twisted pair coil and a conventional loop coil in terms of B₁+ fields, maxSAR₁₀g, and stability of S₁₁ when the coil was deformed was performed. Experimentally measured interelement coupling between individual elements of multichannel arrays was also investigated. ResultsIncreasing the number of twists per length resulted in a more physically robust coil. Poynting vector streamline visualisation showed that the twisted pair coil concentrated most of the energy in the near field. The twisted pair coil exhibited comparable B₁+ fields and improved maxSAR₁₀g to the conventional coil but demonstrated exceptional stability with respect to coil deformation and a strong self-decoupling nature when placed in an array configuration. DiscussionThe findings highlight the robustness of the twisted pair coil, showcasing its stability under shape variations. This coil holds great potential as a flexible RF coil for various imaging applications using multiple-element arrays, benefiting from its inherent decoupling.

Reducing Richtmyer–Meshkov instability jet velocity via inverse design

In this work, we detail a novel application of inverse design and advanced manufacturing to rapidly develop and experimentally validate modifications to a shaped charge jet analog. The shaped charge jet analog comprises a copper liner, a high explosive (HE), and a silicone buffer. We apply a genetic algorithm to determine an optimal buffer design that can be placed between the liner and the HE that results in the largest possible change in jet velocity. The use of a genetic algorithm allows for discoveries of unintuitive, complex, yet optimal buffer designs. Experiments using the optimal design verified the effectiveness of the buffer and validated the machine learning approach to hydrodynamic design optimization.

Study of Iron and Stony Meteorite Ablation Based on Simulation Experiments in an Arc Heater

To observe meteorite ablation, simulation experiments were conducted on the L5 ordinary chondrite and IAB-MG iron meteorites in an arc-heated facility and three flight conditions were reproduced. To mimic the high heating rates and the significant shear stress that meteorites experience during Earth entry, the samples were machined into 9° spherical cones with a 20 mm nose radius. High-quality video, the surface temperature, a time-resolved spectrum, and infrared video were recorded. The atom species were determined via spectroscopy to analyze the ablation products. Due to the electrode erosion and dissociation of air, the atomic lines of copper, nitrogen, and oxygen were detected in all the tests. Although the copper atom is a pollutant to the flow field, the five copper lines were used to determine the flow-field temperature. The ablation rates and effective heat of ablation of both the samples were measured under different conditions. The results indicate that shear stress is the dominant factor influencing meteorite ablation. Furthermore, the diversity between stony and iron meteorites suggests that the mass loss of stony meteorites depends on the fragmentation of the main body and that of iron meteorites depends on the shearing loss of the molten layer. Then, the fusion crusts were analyzed, the microstructures of the samples were obtained, the crust thicknesses were measured, and the elemental distribution of the stony meteorites was determined via energy dispersion spectroscopy. The study results explain the differences in the ablation and recrystallization process between stony and iron meteorites.

Modulate the laser phase to improve the ns-LIBS spectrum signal based on orbital angular momentum.

Aiming to enhance the ns-LIBS signal, in this work, we introduced orbital angular momentum to modulate the laser phase of the Gaussian beam into the vortex beam. Under similar incident laser energy, the vortex beam promoted more uniform ablation and more ablation mass compared to the Gaussian beam, leading to elevated temperature and electron density in the laser-induced plasma. Consequently, the intensity of the ns-LIBS signal was improved. The enhancement effects based on the laser phase modulation were investigated on both metallic and non-metallic samples. The results showed that laser phase modulation resulted in a maximum 1.26-times increase in the peak intensities and a maximum 1.25-times increase in the signal-to-background ratio (SBR) of the Cu spectral lines of pure copper for a laser energy of 10 mJ. The peak intensities of Si atomic spectral lines were enhanced by 1.58-1.94 times using the vortex beam. Throughout the plasma evolution process, the plasma induced by the vortex beam exhibited prolonged duration and a longer continuous background, accompanied by a noticeable reduction in the relative standard deviation (RSD). The experimental results demonstrated that modulation the laser phase based on orbital angular momentum is a promising approach to enhancing the ns-LIBS signal.

Analysis of the Radiation from a Complex Multi-Conductor Transmission Line

The Deployment of Power Line Transmission (PLT) and the development of new broadband services over the telephone network through technology like xDSL (x Digital Subscriber Line), requires higher data rates, consequently higher bandwidths, and operating frequencies. So it is generally accompanied with electromagnetic compatibility (EMC) phenomena, in particular the radiated emissions associated to the deployed system and used cables characteristics. In fact the electrical cable presents variations in their geometry, causing an increase in the electromagnetic radiation. This paper presents a theoretical approach to study a complex transmission line network over ground plane. This approach leads to an analytical expression for the evaluation of P.U.L. parameters of finite length twisted wires lines. These expressions give the capacitances and the inductances values in every point of the cable, the theoretical results are compared to measurements. The formalism is also derived to determine the distribution of the electromagnetic field radiated by Shielded or Unshielded Twisted Pair cables with discontinuity. The obtained results are compared to those provided by a code based on the antenna theory.

Simulation of Eddy Current Losses in Twisted Wires

Twisted wires made of insulated strands, known as stranded conductors or litz wires, are used in various areas where the eddy current loss within the wire needs to be reduced. These areas include induction heating, resonance-based wireless energy transfer, and certain radio frequency devices. Some litz wires consist of thousands of individual conductor strands that are twisted together in multiple stages, creating a hierarchical bundle structure. Computer simulations (typically using finite element analysis) are used in the optimal design of the bundle structure. However, detailed three-dimensional models are computationally demanding. In this work, a two-dimensional finite element model was presented for simulating the eddy current loss in cables made of twisted wires. The key element of the model is considering the bundle structure (generally referred to as 3D configuration conditions) within the cross-sectional model domain. The accuracy of the proposed model is tested against 3D finite element simulations. The new method is shown to be accurate, and its computational cost is by orders of magnitude lower than that of 3D models.

Compact Nanosecond Pulse Generator Based on Distributed Inductive Energy Storage of Twisted Pair Wire

Compact Nanosecond Pulse Generator Based on Distributed Inductive Energy Storage of Twisted Pair Wire

Elemental composition, corrosion resistance and mechanical properties of computer-aided design and computer-aided manufacturing fixed retainers versus conventional fixed retainers.

To investigate the elemental composition, corrosion resistance, and mechanical properties of computer-aided design and computer-aided manufacturing (CAD-CAM) retainers versus conventional fixed retainers (FRs). Eight different retainer wires were investigated. Energy dispersive X-ray spectroscopy was used to determine the elemental composition. Leakage was analysed according to ISO 10271:2020 guidelines. Hardness was tested using the Vickers method with a load of 0.3 kg. The tensile force and tensile strength were evaluated. Multiple comparisons among wires of hardness, tensile force, and strength were conducted using the Welch t-test, with Bonferroni correction. Nickel was present in all wires. The CAD-CAM-FR wire, which contained more nickel than the other wires, had no measurable leakage. The gold-plated wires had the highest total leakage, but did not exceed the ISO standard limit. The hardness of the stainless-steel twisted wires was the highest and that of the CAD-CAM-FR wire was the lowest. The tensile strength of the CAD-CAM-FR wire was significantly lower than that of the other wires and similar to the other twisted-wire retainers. The CAD-CAM-FR wire is likely to have high corrosion resistance and flexibility due to its low hardness.

Comparison of Foiled and Non-Foiled Twisted-Wire Pairs Characteristics due to Coiling Stresses using the Feature Selective Validation Method

This paper presents a technique to evaluate the impact of coiling stresses on foiled and non-foiled twisted pair cables using the Feature Selective Validation Method. The use of twisted pair cables for Internet of Things (IOT) continues to grow due increasing demand for such applications. One of the ways devised by cable designers to minimize electromagnetic interference is the use of foils which comes with additional costs. However, in typical installations, cables could be subjected to repeated coiling and uncoiling stresses which affect performance. There is limited knowledge in literature on the evaluation of the impact of foils on the performance of unshielded twisted pair (UTP) cables when subjected to coiling stresses anticipated during installation, hence the need to conduct this research. In this paper, four UTP cables (foiled and non-foiled) were subjected to three rounds of coiling and uncoiling tests to mimic handling stress expected in typical installations. The Feature Selective Validation (FSV) method was used to assess the impact of the coiling stress test on major performance parameters like return loss, crosstalk and impedance of the four twisted pair cables. The result of the assessment shows that the foiled cables gave the highest resilience to the coiling stress tests in all the pairs for crosstalk, while for return loss and impedance it is in two pairs. The approach presented can be used by cable installers and engineers to undertake an evaluation of cables selected for deployment.

Pengenalan Internet dan Jaringan Serta Pembuatan Kabel Unshielded Twisted Pair (UTP) pada Mahasiswa Universitas Muhammadiyah Jambi

Community Service Activities in the form of internet and network training as well as Making Unshielded Twisted Pair (UTP) Cables for Muhammadiyah Jambi University Students aims to increase students' knowledge of network technology and the benefits of the internet as well as encouraging students to be able to independently manage networks and the internet. The training method used is a form of training outside the classroom using lecture, discussion and question and answer methods as well as direct networking practice. The lecture method used is intended to provide a theoretical explanation of internet and network material. The discussion method is used to explore students' understanding of the material given in lectures. The practical method is used to show directly how to make Unshielded Twisted Pair (UTP) cables. The benefits gained from this training activity are that students are able to make network connections with Unshielded Twisted Pair (UTP) cables and know the benefits of the internet.

Ic measurement of twisted multifilamentary MgB2 wires with non-magnetic sheath over a wide range of temperatures and fields

All-superconducting rotating machines have the potential for meeting the high power density and high efficiency required for electrical aircraft applications. However, very high AC loss encountered in superconducting armature windings could hinder their development. Multifilamentary MgB2 wires are one of the promising candidates for the stator windings, due to their potentially low AC loss properties with small filament size and twist pitches. As the first step, the dependence of critical current and n-value on magnetic fields and temperatures Ic(B, T) and n(B,T), which are basic input parameters for AC loss simulation, needs to be measured. In this work, we present transport Ic measurements in three non-magnetic multifilamentary MgB2 wires (MgB2/Nb/CuNi/CuZn): one large wire with a 0.70 mm diameter and 25 mm twist pitch, and two small wires with a 0.48 mm diameter each and a 10 mm and 30 mm twist pitch respectively. A four-probe direct current method is used to measure Ic of the MgB2 wires with variations in temperature (15 – 35 K) and magnetic field (0 – 5.5 T). Full Ic data for the small wire with 10 mm twist pitch was obtained, and the n-values were mostly less than 20. While the Ic data for the large wire at low fields was more limited due to heating, the n-values were higher and could be up to around 100. The difference is attributed to the different filament sizes. Experiments also found that there is no significant hysteresis in the transport critical current measured by decreasing or increasing magnetic fields due to the non-magnetic sheaths. This non-hysteretic characteristic is critical for lowering AC loss because the additional losses from magnetic sheaths can be eliminated. From the magnetic-field dependence of critical current density, an empirical expression has been developed that provides suitable extrapolations to lower fields for the large wire.

Heat transport with a twist.

Despite the desirability of polymers for use in many products due to their flexibility, light weight, and durability, their status as thermal insulators has precluded their use in applications where thermal conductors are required. However, recent results suggest that the thermal conductance of polymers can be enhanced and that their heat transport behaviors may be highly sensitive to nanoscale control. Here we use non-equilibrium molecular dynamics simulations to study the effect of mechanical twist on the steady-state thermal conductance across multi-stranded polyethylene wires. We find that a highly twisted double-helical polyethylene wire can display a thermal conductance up to three times that of its untwisted form, an effect which can be attributed to a structural transition in the strands of the double helix. We also find that in thicker wires composed of many parallel strands, adding just one twist can increase its thermal conductance by over 30%. However, we find that unlike stretching a polymer wire, which causes a monotonic increase in thermal conductance, the effect of twist is highly non-monotonic, and certain amounts of twist can actually decrease the thermal conductance. Finally, we apply the Continuous Chirality Measure (CCM) in an attempt to explore the correlation between heat conductance and chirality. The CCM is found to correlate with twist as expected, but we attribute the observed heat transport behaviors to structural factors other than chirality.

Fault detection and localization in unshielded twisted pair cable based on observability analysis and reflectometry experimental measurements

In this paper, an efficient method is proposed for detecting and locating a soft fault, i.e. a physical degradation, in a Y-shaped network of unshielded twisted pair cables. The method uses jointly the observability analysis and time-frequency domain reflectometry experimental measurements. The fault detection consists in checking the consistency between the known characteristics of the cable under no-fault and faulty conditions, with the maximum value of a normalized time-frequency cross-correlation function computed on a sliding time window whose length is equal to the boundary exact observability time. The cable transmission speed and the wired network observability time are combined to locate precisely the fault. Soft faults are artificially created by connecting resistors of different values to the test cable. Experimental results show the efficiency of our fault detection and localization method.

A light-powered liquid crystal elastomer semi-rotary motor

Self-excited oscillators are characterized by active energy harvesting from the stable external environment, autonomy and portability, which allow them to act as engines to drive other working devices. Taking inspiration from the pump drill, a semi-rotary motor consisting of a motor rotor and three liquid crystal elastomer (LCE) fibers is constructed in this paper, which can realize self-rotation under stable illumination. Considering the existing twisted wire model and the dynamic LCE model, a nonlinear dynamics model for the semi-rotary motor under stable illumination is established. Numerical calculations witness the existence of two motion modes for the semi-rotary motor under stable illumination, namely the static mode and the self-rotation mode. Under stable illumination, the light-driven contraction of twisted segments in LCE fibers for the winding state can trigger the self-rotation and maintain the continuous periodic motion through the interrelationship between optical energy and damping dissipation. The critical conditions required to trigger the self-rotation are also investigated in detail, as well as the crucial system parameters affecting the self-rotation frequency and amplitude. The proposed self-rotating semi-rotary motor has a simple structure, customizable dimensions and high speed, prompting its potential use in soft robots, energy harvesters, and micro-machines.

Steganographic Techniques for High-Capacity Covert Communication in Images and Videos

Steganography is the art of concealing information within other data to obscure the transmission process. Digital photos are the preferred carrier files due to their ubiquity online. Various steganography techniques exist for hiding sensitive data in video frames, each with distinct strengths and weaknesses. Some applications require total invisibility for critical information, while others can accommodate larger secret messages. Our project conceals messages within visuals, enabling users to select replacement bits instead of employing less secure LSB substitution. Data transmission, the process of sending data from source to destination, often involves slower mediums like coaxial cables and twisted pair wires, which can result in data leaks or losses. To address these issues, fiber optics are employed. Fiber optics transmited data as light beams, minimizing data leakage and incorporating security measures. In our proposed system, we enhance fiber optic encryption through the use of images. Key Words: Steganography, data concealment, digital photos, steganography techniques, data invisibility, LSB substitution, data transmission, coaxial cables, twisted pair wires, fiber optics, data security, image encryption.

On the Frequency Dependence of the PDIV in Twisted Pair Magnet Wire Analogy in Dry Air

This paper presents an experimental verification of a PDIV model for twisted-pair magnet wires (TPMW). The model is physically rooted in an inception criterion based on secondary electron feedback and parametrizes the PDIV of wedge-shaped gas gaps (such as TPMW) solely in terms of its reduced coating thickness—the ratio of coating thickness to its relative permittivity. According to the literature, the coating’s permittivity and thickness should play a significant role in determining the PDIV. Still, no explicit quantification of their concurrent effects is often given, and they are frequently treated as decoupled parameters. Therefore, extensive measurements of PDIV of samples analogous to TPMW coated with dielectric materials of different permittivity (sealed and unsealed alumina, silicone polyester, and perfluoroalkoxy alkane) and thickness (≈45 to 80 μm) are performed. The PDIV of the test samples is determined under sinusoidal test voltage in the frequency between 10 to 60 000 Hz. It is shown that the PDIV can be predicted based on the relative permittivity and thickness of the coating, and the frequency dependence is due only to the change of permittivity with frequency. Temperature and pressure are kept approximately constant at their ambient values (ca. 23 °C & 970 mbar), and only dry air is used to exclude the effect of humidity on the insulation’s permittivity. Ultimately, the role of surface charge is discussed qualitatively by comparing the PDIV with the partial discharge extinction voltage (PDEV) and their repetitive counterparts (RPDIV, RPDEV).

High toughness of nanotwinned copper lines after annealing

High toughness and tensile strength are favorable factors to advance the applications of Cu lines. In this study, 60-μm-wide nanotwinned Cu (NT-Cu) and regular Cu lines were electroplated and further heat-treated. The annealing-induced effect on the mechanical properties was then investigated. Results showed that the tensile strength of the NT-Cu lines was apparently greater than that of the regular Cu counterparts. Under annealing, the tensile strength of the NT-Cu lines dropped slightly due to thermal-induced detwinning effect. However, such a heat treatment at 150 °C for 3 h greatly enhanced their elongation (7.0%–13.4%) and toughness (32.0 MJ/m3 to 64.9 MJ/m3). No obvious grain growth was observed in the NT-Cu after annealing at 250 °C for 3 h. Meanwhile, grain coarsening occurred in the regular Cu lines leading to significant decrease in the tensile strength, and their toughness was only 6.6 MJ/m3 after the annealing at 150 °C for 3 h. Additionally, the microstructures of the NT-Cu were analyzed by transmission electron microscopy and electron backscattered diffraction. Hall-Petch equation and confined layer slip (CLS) model were also employed to estimate and correlate the yield strength of the NT-Cu lines with twin spacing and average grain size.

Degradation-Sensitive Health Indicator Construction for Precise Insulation Degradation Monitoring of Electromagnetic Coils.

Electromagnetic coils are indispensable components for energy conversion and transformation in various systems across industries. However, electromagnetic coil insulation failure occurs frequently, which can lead to serious consequences. To facilitate predictive maintenance for industrial systems, it is essential to monitor insulation degradation prior to the formation of turn-to-turn shorts. This paper experimentally investigates coil insulation degradation from both macro and micro perspectives. At the macro level, an evaluation index based on a weighted linear combination of trend, monotonicity and robustness is proposed to construct a degradation-sensitive health indicator (DSHI) based on high-frequency electrical response parameters for precise insulation degradation monitoring. While at the micro level, a coil finite element analysis and twisted pair accelerated degradation test are conducted to obtain the actual turn-to-turn insulation status. The correlation analysis between macroscopic and microscopic effects of insulation degradation is used to verify the proposed DSHI-based method. Further, it helps to determine the threshold of DSHI. This breakthrough opens new possibilities for predictive maintenance for industrial equipment that incorporates coils.