Twisted Pair Research Articles

Expanding the Capability of a Legacy Combustion Flame Tube to Test High-Temperature Engine Materials in Relevant Environments

Abstract New materials and component designs are needed to advance gas turbine engine technology and provide the performance and efficiency needs for future applications. In order to advance these materials, testing in combustion environments is a critical step prior to engine testing. In this work, we detail the design and the fabrication of a materials test sector in a flame tube combustor facility. The facility simulates a combustion environment similar to that experienced by components in gas turbine engines. The flow regime is characterized by a combination of high-temperature, high-heat flux, and high-velocity that components experience in gas turbine engines. Exposure of components in this facility allows for the study of combined environmental effects and the impact on both coating and substrate durability. The test facility may operate across a wide range of pressures from 275 to 400 psig (1896–2758 kPa) and an air flowrate of 5 lb/s (2.27 kg/s). While combustion gas temperature is expected in excess of 3000 °F (1649 °C), 900 °F (482 °C) cooling air may be supplied to the backside of components or test articles. The flame tube combustor was previously used to evaluate fuel injectors and combustion products, and the new test configuration will also allow for materials exposure to complex, engine-like conditions. The interior of the test section was additively manufactured from GRCop-84 and cryogenically fit and brazed to a stainless-steel 304 housing. The use of a copper liner minimizes welds and, with active cooling, is expected to provide better durability over traditional hardware using stainless-steel or Inconel with a ceramic liner. The test section has two opposing 9.5 in × 3.125 in (241 mm × 80 mm) removable windows that can accommodate articles up to 3.5 in (89 mm) tall. This modular design allows for custom platforms to hold coupons, panels, or airfoil shapes to be tested with minimal re-engineering or fabrication. The bolted joint and sealing remains consistent, so any new testing only needs to work within the existing design footprint. This paper will provide an overview of the facility capabilities, design considerations, as well as thermal and structural analysis of the hardware. Future testing of ceramic matrix composite (CMC) airfoils and advanced environmental barrier coatings (EBCs) will also be discussed.

Transient induced response on cables by lightning electromagnetic pulse with different experimental conditions

The coupling of lightning electromagnetic pulse (LEMP) on cables can generate disruptive surge current and voltage, which may cause damage to devices or systems connected with cables. In this paper, a double toroidal magnetic field, through injection of an 8/20 μs lightning current into a double toroidal coil, is generated to induce indirect effects on nine communication/electrical cables. The impacts of different types and shielding methods of communication cables on induced surge current are evaluated, and the results show that twisted-pair cables with shielding layer have the best shielding effectiveness, with the ability to absorb more energy on the communication cables from LEMP. In addition, the study's findings demonstrate that the induction properties of cables are independent of the number of cores, but related to the shielding layer of cables. Meanwhile, simulation analysis in CST Studio Suite is carried out here, and results are basically similar to experimental results, with the difference attributed to the ignorance of some losses in the simulation environment. Finally, the magnetic field strength at each point of the LEMP is simulated, with some engineering proposals for the actual and simulated experiments.

Detecting Manufacturing Defects on Printed Circuit Boards Using Metamaterial-Based Circular Microstrip Patch Antenna

In this study, a microstrip circular patch antenna is designed having a metamaterial-based (MTM) ground plane to detect manufacturing defects of short circuits and open circuits on printed circuit boards (PCB). In that regard, PCB specimens of FR-4 as the substrate and copper microstrip lines as the conductive wiring lines are designed and manufactured. Five vertical copper lines printed side by side on the top of the substrate are used to demonstrate the working mechanism of the designed antenna sensor. Two different defect scenarios of open and short circuits with controlled locations are studied to determine variations in the return loss data of the proposed structure. MTM cell structures with cross lines enclosed by an octagon ring are periodically placed as part of the ground plane of the proposed antenna to obtain higher sensitivity of the designed and manufactured sensor. Antenna return loss behaviors in terms of the locations of the faults are employed to prepare a database to detect not only the presence of the faults but also determine their locations. Since the samples to be measured are not irreversibly damaged during the testing process, the proposed design can be considered a non-destructive measurement method to provide information about the type and location of defects with real-time measurement data.

Magnetically Activated Ingestible Pill with Archimedes Screw for On‐Demand Sampling of Intestinal Microbiome

AbstractTechnologies capable of noninvasively sampling different locations in the gut upstream of the colon will enable new insights into the role of organ‐specific microbiomes on human health. Herein, an ingestible pill for the sampling of gut lumen based on one of the earliest hydraulic machines known as an Archimedes screw is reported. The design contains twisted wires as Archimedes screw driven by a motor, wirelessly activated using a magnet. The sampling performance of the screw‐pump pill is characterized using realistic in vitro models and validated in vitro using E. coli expressing different fluorescent proteins. The use of the Archimedes screw enables the pill to sample the dense GI environment. The pill is also tested ex vivo in the pig intestine and in vivo in pigs. Herein, the results show that the bacterial populations recovered from the pill's chamber closely resemble the targeted bacterial population of the microenvironment to which the pill is exposed. Such ingestible devices have the potential to revolutionize the understanding of the spatial diversity of the gut microbiome and its response to medical conditions and treatments.

Fabrication of Shape‐Controlled Copper Line Arrays by Meniscus‐Confined 3D Microprinting on Insulating Substrates

Meniscus‐confined electrodeposition (MCED), as a 3D printing process, exhibits excellent capabilities in microstructure fabrication. However, it faces numerous challenges, particularly when integrating with different substrates, especially insulating ones and cross‐layer interconnection. This study intends to investigate the impact of factors such as nozzle diameter, flight height of the nozzle over insulating substrates, and applied current by MCED on micro/nanoscale metal structures, to fabricate shape‐controllable and nanogap copper lines. As the flight height of the nozzle increases, there is no significant variation in the line height (≈60 nm) or width (≈15 nm) of the printed copper lines. And copper lines are successfully fabricated with consistent feature size oversteps totaling 1.2 μm in height. Additionally, highly dense copper line arrays are fabricated, achieving a minimum wire spacing of 120 nm. Remarkable stability and simplicity are realized in producing high‐resolution copper microstructures, demonstrating an acceptable degree of variability in insulating substrates and promising applications in integrated microsystems.

Accuracy of lingual fixed retainers fabricated using a CAD/CAM bending machine.

Lingual fixed retainers, made from 0.0175-inch 3-strand twisted stainless steel wire (TW) and 0.016 × 0.022-inch straight rectangular wire (RW), are generally used in clinical practice. This study aimed to calculate their accuracy by comparing the discrepancy between computer-aided customized retainers made from these two types of wires. Eleven orthodontic patients were selected, resulting in 22 maxillary and mandibular three-dimensional printing dental models. Two types of lingual fixed retainers were bonded from canine to canine. To determine the accuracy, five points were chosen for each model, resulting in 110 selected points. The absolute values of the distances on the x-, y-, and z-axes were measured to compare the accuracy of the two types of computer-aided retainers. The accuracy of the two types of retainers did not differ significantly in the x- and z-axes, but only in the y-axis (P < 0.01), where RW-fixed retainers exhibited a slightly but significantly increased distance compared to the TW. Both types of retainers showed high accuracy; however, RW had a slight but statistically significant difference along the y-axis compared with TW. This type of computer-aided design/computer-aided manufacturing bending machine is limited to two dimensions, and the dental arch is curved. Therefore, RW may require slight manual adjustment by the practitioner after manufacturing.

Compact lab-on-printed circuit board (PCB) for free-surfactant silver nanomaterial synthesis

This study introduces a compact Lab-on-Printed Circuit Board (PCB) device featuring thermal integrated microfluidic channels designed for nanoparticle synthesis. Commonly, complex heating chambers are employed to expedite reactions and enhance nanomaterial productivity, yet they pose challenges in temperature control and mixing rates within the reaction chamber. To address these issues, we propose a compact device composed of PDMS microfluidic channels and a PCB platform. The PCB heater, constructed to precisely regulate temperature within the microfluidic channels, utilizes copper lines as heating resistors, while an Arduino kit is employed for temperature measurement and control. Leveraging a Proportional–integral–derivative (PID) controller through programming, the device achieves rapid temperature increase and stable control within the microfluidic channels. Experimental validation demonstrates the operational principles and capabilities of this device, showcasing observable changes in nanoparticle size and morphology. Discussions on these observed results are included in this work.

Interconnects Materials for Integrated Circuit Technology Below 5 Nm Node

As the integrated circuits is scaled few problems appear at the lowest levels of interconnects — high resistance of copper lines and copper electromigration. High resistance is connected with the increasing contribution of the electron surface scattering and grain boundary scattering. Moreover, copper lines require barrier layers decreasing the cross-section of the copper part of the line. Also the resistance of copper to electromigration is insufficient for the technology node below 5nm. Therefore, it is necessary to look for alternative materials to replace copper, which will provide high resistance to electromigration and low resistance of the lines. The most promising candidates are Ru, Mo, Rh, Ir. The advantages and disadvantages of these materials are considered in this paper.

Enhancing all-position weldability and weld quality via an innovative laser-GMAW hybrid welding technique with copper liner

The change in welding position results in varied effects of gravity on the weld pool behavior. Conventional welding methods face difficulties when adjusting to welding in different positions. To address these challenges, a novel all-position welding technology, laser-GMAW hybrid welding with copper liner (CL), was introduced. CL serves a dual purpose. First, from flat to vertical welding, it supports the weld pool across various positions, thereby preventing root sagging or burn-through defects at the root of the weld in this range. Second, it facilitates accelerated weld pool solidification and inhibits its downward movement during vertical to overhead welding positions, forming the back continuous reinforcement. To quantitatively analyze the impact of CL on the temperature field during welding, finite element software was employed in this study. Moreover, the study also explored the effects of the size of the forming groove, welding current, and laser power on the weld appearance during overhead welding. As a result, with constant welding parameters, ideal welds with continuous back reinforcement were successfully achieved at five representative positions within the 0–180° range.

Effects of a DC Offset on Lifetime and PD Activity During AC Aging Tests on Enameled Twisted Pairs

Effects of a DC Offset on Lifetime and PD Activity During AC Aging Tests on Enameled Twisted Pairs

P‐180: Dynamic Invocation of Liquid Crystal Overdrive Tables by Utilizing Temperature Sensor Integrated in the LCD Cell

We proposed a method for dynamic Invocation of LC OD tables based on temperature changes to improve LC response time. A temperature sensor utilizing copper line with an accuracy of ± 1℃ was integrated within the liquid crystal cell. Temperature range 0‐40℃ was divided into three segments, each with an assigned optimal OD table, and the circuit system realized dynamic invocation of LC OD tables based on temperature changes.

Combining Dipole and Loop Coil Elements for 7 T Magnetic Resonance Studies of the Human Calf Muscle.

Combining proton and phosphorus magnetic resonance spectroscopy offers a unique opportunity to study the oxidative and glycolytic components of metabolism in working muscle. This paper presents a 7 T proton calf coil design that combines dipole and loop elements to achieve the high performance necessary for detecting metabolites with low abundance and restricted visibility, specifically lactate, while including the option of adding a phosphorus array. We investigated the transmit, receive, and parallel imaging performance of three transceiver dipoles with six pair-wise overlap-decoupled standard or twisted pair receive-only coils. With a higher SNR and more efficient transmission decoupling, standard loops outperformed twisted pair coils. The dipoles with standard loops provided a four-fold-higher image SNR than a multinuclear reference coil comprising two proton channels and 32% more than a commercially available 28-channel proton knee coil. The setup enabled up to three-fold acceleration in the right-left direction, with acceptable g-factors and no visible aliasing artefacts. Spectroscopic phantom measurements revealed a higher spectral SNR for lactate with the developed setup than with either reference coil and fewer restrictions in voxel placement due to improved transmit homogeneity. This paper presents a new use case for dipoles and highlights their advantages for the integration in multinuclear calf coils.

On the frequency dependence of the PDIV in twisted pair magnet wire analogy in humid air

The partial discharge inception voltage (PDIV) of low-voltage induction motor turn-turn insulation analogy is investigated for variable relative humidity (RH) of the surrounding air (temperature and pressure are kept constant close to their ambient values). Three materials, perfluoralkoxy alkane, sealed and unsealed alumina (UA), are employed as the dielectric coating (insulation) of test samples. Each material’s dielectric properties change differently with RH—of these, relative permittivity is regarded as the most crucial, as it was previously proven to be, along with the coating’s thickness, the key factor in determining the PDIV in dry air conditions. To further vary the value of permittivity and thus provide larger data sets for the verification study, the frequency of the excitation voltage is also varied between 1 Hz and 50 kHz. The obtained experimental data are compared against the PDIV predictions obtained by a breakdown model based on the reduced thickness of the coating (ratio of the coating thickness to its relative permittivity). Satisfying agreement between the measured and predicted PDIV are obtained for the first two materials, whereas significant discrepancies are seen for the UA material. For this case, surface conductivity is introduced into the prediction model and much better fits to the experimental data are obtained for a suitable value of surface resistance. It is hence demonstrated that the model is able to satisfactorily predict the PDIV for three substantially different materials when the RH of the surrounding air is varied between 10% – 80% .

Evaluating the Impact of Geometric Dimensions of a Multi-Split Ring Resonator

In this paper, a metamaterial unit cell is designed and simulated based on the concept of multiple split-ring resonators (SRRs) in a compact size. The presented nested modified SRR resonator construct has the advantage of achieving more usable split gaps by increasing capacitance, resulting in a lower operational resonance frequency and improved sensitivity over typical SRR metamaterials. The impact of several split ring resonator geometric characteristics, such as the gap space, the width of the copper lines, the inner rings length, and the outer ring length on magnetic permeability and permittivity was analyzed. The modified metamaterial can be utilized for 5G mobile applications.

Machine learning optimization strategy of shaped charge liner structure based on jet penetration efficiency

Shaped charge liner (SCL) has been extensively applied in oil recovery and defense industries. Achieving superior penetration capability through optimizing SCL structures presents a substantial challenge due to intricate rate-dependent processes involving detonation-driven liner collapse, high-speed jet stretching, and penetration. This study introduces an innovative optimization strategy for SCL structures that employs jet penetration efficiency as the primary objective function. The strategy combines experimentally validated finite element method with machine learning (FEM-ML). We propose a novel jet penetration efficiency index derived from enhanced cutoff velocity and shape characteristics of the jet via machine learning. This index effectively evaluates the jet penetration performance. Furthermore, a multi-model fusion based on a machine learning optimization method, called XGBOOST-MFO, is put forward to optimize SCL structure over a large input space. The strategy's feasibility is demonstrated through the optimization of copper SCL implemented via the FEM-ML strategy. Finally, this strategy is extended to optimize the structure of the recently emerging CrMnFeCoNi high-entropy alloy conical liners and hemispherical copper liners. Therefore, the strategy can provide helpful guidance for the engineering design of SCL.

НАУКОВА КОНЦЕПЦІЯ CТВОРЕННЯ ВИСОКОВОЛЬТНИХ МОБІЛЬНИХ ЕЛЕКТРОТЕХНІЧНИХ СИСТЕМ РЕЗОНАНСНОГО ТИПУ ЗІ ШВИДКОДІЮЧИМИ КЕРУВАННЯМ І ПАРАМЕТРИЧНОЮ СТАБІЛІЗАЦІЄЮ РЕЖИМІВ НАВАНТАЖЕННЯ

A new scientific concept has been developed for the creation of high-voltage electro-technical systems (ETS) of a reso-nant type based on the implementation in them of series high-quality inductive-capacitive circuits (ICC) and high-frequency (HF) resonant currents. This makes it possible to repeatedly increase the alternating voltage on the reactive elements of the ICC and on the load connected in parallel to one of the elements, and to ensure a significant decrease in the impulse energy of the ETS without changing their average power, as well as to increase the speed of control and parametric stabilization of the load modes of the ETS even with a rapid decrease in the electrical resistance of this load to almost zero, as in the case of electrical breakdown of its insulation. The generation of resonant currents with a fre-quency of up to 40 kHz in the ICC, which has a coil with an inductance of ~ 25 mH and a Q factor up to 270 (made of multi-core twisted copper wires of the " litzendraht " type) and a ceramic capacitor with a capacity of ~ 3.5 nF and a Q factor &gt; 1000, ensures the realization of the QICC up to 260 and the corresponding increase in the ratio of the ETS out-put voltage to the input voltage without the use of step-up transformers. When connecting such an ETS to a source of alternating voltage of 220 V, a voltage of up to 40 kV can be generated at the output of the ETS. A significant increase in the frequency of currents leads to a significant decrease in the mass-dimensional characteristics of ETS and the pos-sibility of creating their samples mobile (weighing up to 5 kg), and if necessary, autonomous, in particular with power supply from batteries. The new scientific concept is aimed at creating a resonance-type ETS for safe and reliable moni-toring and diagnostics of the technical condition of high-voltage insulation of power cables, powerful electric machines and other energy objects of the critical infrastructure of Ukraine. Such ETS can also be effectively used for charging to high voltages capacitive energy storage (CES) in technological installations for the production of electro-spark micro- and nano-powders with unique properties, as well as for high-voltage electro-hydro-pulse processing of various mate-rials and environments. It has been established that the power of these ETS increases with a decrease in the ratio of the capacitances of the capacitors ICC and CES. References 40, figures 4.

Derivation of Ambient Enhancement Factors of Impregnated Twisted Pairs for Partial Discharge Risk Evaluation

Partial discharge (PD) is the main issue challenging the electrical machine (EM) insulation system for more electric aircraft (MEA) applications. Indeed, the trend of adopting higher DC link voltage and fast switching device further boost the risk of PD. Partial discharge inception voltage (PDIV) is mostly dominated by ambient conditions (i.e., temperature, pressure, and humidity), and their influence is accounted for through experimentally determined ambient enhancement factors. For non-impregnated windings, ambient enhancement factors are suggested by both IEC 60034-18-41 and recent literature. However, in many applications, EMs’ windings are often impregnated with resin to improve thermal performance, mechanical resistance, and electrical insulation. In this case, no indications of the enhancement factors for PD risk assessment are given. The ambient enhancement factors are experimentally determined in this paper to enable the PD risk evaluation for impregnated windings. These factors are obtained relying on an extensive PD investigation, where PDIV and partial discharge extinction voltage are measured under variable temperature, pressure, and humidity conditions. Finally, the tests are performed on different wire types and motorette samples to validate the applicability of the derived factors.

Comparative Analysis of Network Development Local Area Network (LAN) Fiber Optical Cable with Unshielded Twisted Pair (UTP) Cat 6 Cable at SMK Negeri 2 Tasikmalaya

The LAN Network at SMK Negeri 2 Tasikmalaya previously used media UTP Cat5e network with poor performance due to bandwidth UTP Cat5e is only 200 Mb/s, therefore the school choose to replace it network media with fiber optics, with a bandwidth that can reach 1 Gb/s. On the other there is still UTP Cat6 with the same bandwidth of 1Gb/s at a cost installation is lower than fiber optic network installation. Data collection on performance is carried out using the Quality of Service (QoS) approach with the parameters measured, namely Delay, Jitter, Packet loss and Throughput using Wireshark software. Performance of fiber optic and UTP Cat6 networks at SMK Negeri 2 Tasikmalaya in categorize “Good” according to Telecommunications and Internet Protocol Hormonization Over Network (TIPHON) standards. Test results from optical fiber obtained a delay of 2.58 ms, jitter of 2.38 ms, packet loss of 0.254 and throughput of 805.92 Mbps. The test results of the UTP Cat6 cable were obtained delay of 5.59 ms, jitter of 5.21 ms, packet loss of 0.559 and throughput of 623.73 Mbps.

Integration of craftsman spirit of great powers into the practical classroom teaching of computer network foundation

It is a trend in curriculum construction to extend ideological and political education from specialized ideological and political courses to curriculum ideological and political courses. Based on the characteristics of private applied undergraduate courses, this article takes the practice of "RJ-45 interface twisted pair" in computer network courses as an example to explore the spiritual power of ideological elements, and integrates curriculum education into teaching case design and teaching process to cultivate students' spiritual power and achieve the goal of comprehensive education.

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 &gt;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.