Electrical Interconnects Research Articles

Package Design Thermal Optimization for Metal-Oxide Gas Sensors by Finite Element Modeling and Infra-Red Imaging Characterization.

We designed a 3D geometrical model of a metal-oxide gas sensor and its custom packaging and used it in finite element modeling (FEM) analysis for obtaining temperature and heat flux distribution. The 3D computer simulation, performed with GetDP software (version 3.5.0, 13 May 2022), accurately predicted the temperature distribution variation across the entire assembly. Knowing the temperature variation and the location of the hot spots allowed us to select the best electrical interconnect method and to choose the optimal materials combination and optimal geometry. The thermal modeling also confirmed the need to use a low thermal conductivity material to insulate the MOX sensor since the latter is heated to its operational temperature of 250 °C. For that purpose, we used the in-house formulated xerogel-epoxy composite of thermal conductivity of 0.108 W m-1 K-1, which is at least 30% less compared to the best-in-class among commercially available materials. Based on the 3D FEM outputs, we designed, assembled, and characterized a fully functional packaged MOX gas sensor in several configurations. We measured the temperature distribution on all parts of the MOX gas sensor assembly using a thermal imaging infrared (IR) microscope. The results of 3D FEM are in good agreement with the temperature distribution obtained by the non-contact IR thermal characterization.

Highly conductive and stretchable filament for flexible electronics

Conductive and stretchable filaments are crucial for advancing additive manufacturing, particularly in flexible electronics. However, existing conductive filaments suffer from limitations in conductivity and stretchability. To overcome these challenges, this study presents a highly conductive and stretchable filament for material extrusion type 3D printing. The developed filament achieves an initial electrical conductivity of 558 S/cm and maintains low resistance up to 60 % strain with 10 vol% silver loading. This significantly surpasses the performance of commercial filaments and previous literature reports. The addition of polyethylene glycol (PEG) as a plasticizer for the silver filled thermoplastic polyurethane (Ag-TPU) composite enhances extrusion and improves filament surface quality. The printability of the filament in material extrusion 3D printing was evaluated, and the electrical conductivity of the printed objects was assessed. Two demonstrator structures, an electrical interconnection and a capacitive strain sensor, were successfully prototyped, showcasing the potential applications of this filament in stretchable electronics. The developed filament paves the way for creating intricate and stretchable electronic devices using material extrusion printing techniques. These advancements contribute to the field of additive manufacturing and enable the fabrication of flexible electronic components with enhanced conductivity and stretchability.

A special method for simultaneous optimization of electrical grid interconnections and cable size in wind farms

<span lang="EN-US">Modern wind farms are considered one of the most important sources of energy today. The biggest cost of the farm is the cost of electrical connection to the farmers (constituting the largest part of the aesthetic cost of the farm) and finding the best method for electrical connection (the optimal method) for wind turbines (WTS), as well as the optimal size and measurement of electrical cables. Here, the (harmonious) search algorithm solves the optimization problem and the method of digging the soil in order to lay the cables in it. Two cases will be discussed in order to calculate the optimal size of the cables, namely partial calculation and optimal calculation for connection schemes in the best method for wind farms (OWFS). Also, the total cost, shipping methods, methods of digging extensions into the soil and the different classifications for turbines (wind turbines) will be addressed in order to obtain the best investment for them, so that we reach the optimal delivery and the lowest possible cost in a coordinated and thoughtful manner.</span>

Development of 3D Printable Highly Flexible Siloxane Elastomers for Direct Ink Writing (DIW) of Soft Robotic Actuators for Space Applications

There is an interest in soft robotics for various space applications within low gravity and tight space environments to navigate, observe and even service various components within space assets, spacecraft and planetary stations. As an example, in an emergency, such as a pipe system failure occurring in a spacecraft, a soft robot may be able to assist in navigating the structure to detect the location and means of failure. The manufacturing of soft robotic actuators in space can be crucial. In addition, the fabrication of soft robotic tooling in a single step plays a critical role in space. 3D printing systems allow the manufacturing of soft robotic actuator parts in a single step. Stereolithography (SLA) and digital light processing (DLP) systems are not convenient because of the space environment. However, direct ink writing (DIW) which is the most commonly available and affordable system compared to SLA or DLP can be utilized to produce 3D objects, in addition, the DIW process permits the ability to in situ produce composite structures during the printing process. Various inorganic particles can be inserted within the elastomer print to control the mechanical, electrical and magnetic properties on-demand to produce smart or multi-functional soft robotic actuators and structures.The current work focuses on the development of a highly flexible and low (or nearly no) cytotoxicity silicone-based elastomer via thiol-ene click reaction that allows rapid polymerization of an elastomer to prevent the collapse of the structure during the printing. The work also demonstrates the use of this novel UV-durable elastomer to produce structures with embedded electrical interconnects and sensors for in-situ measurement of temperature and strain. In this study Poly(mercaptopropylmethylsiloxane-co-dimethylsiloxane) (M-MPS) was first prepared through the cohydrolysis-condensation reaction of 3-Mercaptopropylmethyltrimethoxysilane (MPS) and dimethyldimethoxylsilane (DMDES) with water and hydrochloric acid. Then M-MPS was compounded with various molecular weight vinyl-terminated polydimethylsiloxane (VPS) (MW~800-25000) and different dosage (0.1- 4.0 wt%) of a photoinitiator (1:1 weight ratio of 2-Hydroxy-2-methyl-phenyl-propane-1-one (PI 1173) and phenyl bis (2,4,6-trimethylbenzoyl) phosphine oxide (PI819)). For example, Figure 1 depicts the change in the viscosity of (M-MPS)-VPS 6000 2 wt% when it exposes to UV light irradiation. When (M-MPS)-VPS 6000 2 wt% was exposed to UV light irradiation, it polymerized at ~2 sec which is enough time to retain the structure during printing. To elucidate the properties of synthesized elastomer, FTIR, NMR, SEM, and tensile test measurements were performed. Furthermore, the synthesized elastomer was loaded with conductive inorganic particles so as to utilize the printed material as a temperature and tactile sensor (and sensor array). In addition, other printing variables were evaluated to produce 2D/3D structures of the pure and composite elastomers, such as the effect of the power and wavelength of UV light source, loading different types of conductive powders, and thiol-ene ratio. Acknowledgments: Work supported by a subcontract under the NASA-EPSCOR program (project number is 80NSSC20M0218). The authors would like to thank our NASA technical monitor Mr. Curtis Hill and project manager Dr. Melanie Page due to their contributions. Material characterization and imaging work were made possible with the support of the West Virginia University Shared Research Facilities (SRF). Figure 1

(Invited) multi-Modal Nanoarray Sensors for Chemical Differentiation and Quantification

Integration of multiple sensors in a so-called sensor array platform allows multi-analyte detection and enhanced selectivity. However, the demanding requirement of device integration comes along with less than desired sophistication of electrical interconnects with increasing circuit complexity. In the past decade, we have been focused on establishing a multi-modal sensing platform based on a single nanostructured device. Such a single device platform can be operated with different modes such as photocurrent, resistance, potential, and impedance. These nanoarray sensors have been fabricated with a good scalability using vapor to solution phase depositions. The array composition could be rationally designed from pristine to heterogeneous across metals, ceramics, and polymers. Depending on the comprised material composition, decoration of nanoparticle sensitizers such as perovskite, metal oxide, or noble metal may enable drastic boosting of sensor performance under various gaseous mixtures such as nitrogen oxide (NOx), hydrocarbons (HCs), carbon mono-oxide (CO), and hydrogen in atmospheres. Toward mixed multi-analyte conditions, such a new chemical sensor allows differentiated detection as well as low-concentration quantification of multiple species in a single-device platform. Machine learning as driven by the multimodal sensor datasets is utilized to add and enhance the single sensor platform performance in terms of accuracy, detection range, and speciation differentiation.

Gold Nanoparticles-Functionalized Cotton as Promising Flexible and Green Substrate for Impedometric VOC Detection.

This work focuses on the possible application of gold nanoparticles on flexible cotton fabric as acetone- and ethanol-sensitive substrates by means of impedance measurements. Specifically, citrate- and polyvinylpyrrolidone (PVP)-functionalized gold nanoparticles (Au NPs) were synthesized using green and well-established procedures and deposited on cotton fabric. A complete structural and morphological characterization was conducted using UV-VIS and Fourier transform infrared (FT-IR) spectroscopy, atomic force microscopy (AFM), and scanning electron microscopy (SEM). A detailed dielectric characterization of the blank substrate revealed interfacial polarization effects related to both Au NPs and their specific surface functionalization. For instance, by entirely coating the cotton fabric (i.e., by creating a more insulating matrix), PVP was found to increase the sample resistance, i.e., to decrease the electrical interconnection of Au NPs with respect to citrate functionalized sample. However, it was observed that citrate functionalization provided a uniform distribution of Au NPs, which reduced their spacing and, therefore, facilitated electron transport. Regarding the detection of volatile organic compounds (VOCs), electrochemical impedance spectroscopy (EIS) measurements showed that hydrogen bonding and the resulting proton migration impedance are instrumental in distinguishing ethanol and acetone. Such findings can pave the way for the development of VOC sensors integrated into personal protective equipment and wearable telemedicine devices. This approach may be crucial for early disease diagnosis based on nanomaterials to attain low-cost/low-end and easy-to-use detectors of breath volatiles as disease markers.

Electrically conductive adhesive-free interconnection of shingle solar cells

This work deals with the usage of electrically conductive adhesives (ECA) for the interconnection of shingle solar cells. In a detailed study on small-format shingle modules characterized by current-voltage, electroluminescence and magnetic field imaging measurements, the impact of an ECA reduction (usage of ECA dashes instead of a continuous ECA line) as well as the complete omission of ECA is investigated with regards to the electrical interconnection quality. Inter alia, it is demonstrated that lamination can improve interconnection quality in ECA-containing shingle joints and establish interconnection in ECA-free shingle joints by pressing adjacent shingles together and thereby forming a busbar-to-busbar contact of decent electrical quality. In a follow-up experiment, the approach of simply omitting the usage of ECA for shingle interconnection is tested with regards to thermal cycling, damp heat and dynamic mechanical load tests finding only minor compromises, if at all, in terms of long-term stability.

Inter-comparison of spatial models for high shares of renewable electricity in Switzerland

This study presents an inter-comparison of three structurally different electricity system models (EXPANSE, Nexus-e, and OREES) with sub-national spatial resolution in Switzerland in 2035. We analyze technology and regional implications of three targets for electricity generation from new renewable sources (17 to 25 TWh/year from solar PV, wind, biomass, and waste incineration) and compare results at a national level as well as at a higher spatial resolution of Swiss cantons and municipalities. All three models align on high capacities of solar PV in 2035 as the key technology for reaching the three targets, but there is flexibility where PV can be placed to achieve the targets: either on roofs and facades or also on land. Electricity interconnection with Europe remains of key importance in Switzerland because any increases in electricity demand or lower deployment of new renewable generation are compensated by import. For the rest, the three models provide internally-consistent storylines of future strategies for Switzerland: a future with a diversified range of technologies (EXPANSE), a future with the focus on decentralized rooftop solar PV with batteries (Nexus-e), and a future with the prioritization of most productive areas for wind and solar PV, including open-field PV (OREES).

Exploration of a neural-network-based joint method of mapping and wavelength assignment in optical network-on-chip

Optical network-on-chip (ONoC) is promising to provide higher bandwidth and lower latency, compared with the traditional electrical interconnects at either chip-scale or wafer-scale. There is research on the impact of mapping or wavelength assignment on reliability in ONoC. However, mapping and wavelength assignment have an interactive influence on each other, pushing a necessity of research on the joint method. In addition, there are various ways to realize the joint method, which have an influence on the reliability and thus the power efficiency. In this paper, we propose a neural-network-based iterative joint method of mapping and wavelength assignment. Compared to the methods without considering the interactive influence, the proposed iterative joint method based on the continuous Hopfield neural network provides a worst-case optical signal-to-noise ratio (OSNRWC) improvement of at least 61% under the considered applications. Compared to the simultaneous joint method and two-step joint method, the proposed iterative joint method obtains an OSNRWC improvement of at least 17.9% and 64.6%, respectively, under the considered applications. Thanks to the improvement of OSNR, the laser power is reduced by 87.9% by using our method of wavelength assignment, compared to the random method of wavelength assignment.

Projects of common interest? Evaluation of European electricity interconnectors

This paper evaluates the new electricity interconnection projects on the fifth list of Energy Projects of Common Interest. A cost-benefit analysis is carried out with electricity market modelling. The results show that out of the 13 planned lines, 12 are socially beneficial. Moreover, the sensitivity checks highlight that most projects remain beneficial despite differing market assumptions. In those scenarios, where Europe's average wholesale electricity price is relatively higher, the projects yield greater social benefits. A complementarity index is also calculated, showing that PCI projects are generally weak competitors to each other.

Utilising blue laser over infrared laser to enhance control of penetration depth and weld strength for producing electric vehicle battery interconnects

Utilising blue laser over infrared laser to enhance control of penetration depth and weld strength for producing electric vehicle battery interconnects

Second Harmonic Current Suppression and Dynamic Response Improvement for V2G System

Electric vehicles interconnect and interact with the grid bidirectionally through a vehicle-to-grid (V2G) system. In V2G, the output power on the AC side pulsates at twice the grid frequency 2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> , which leads to the presence of a second harmonic current (SHC) on the DC side and reduces the reliability of the system. A bandstop filter (BSF) with a center frequency of 2 <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">o</sub> is introduced in the voltage sampling loop to suppress the SHC. A digital implementation of the BSF is proposed to apply at arbitrary frequencies, which avoids the cost increase and provides high simplicity and flexibility. An adaptive PI control method is further proposed to improve the dynamic performance, which adjusts the PI parameters in real-time according to the inductor current. A 3.5 kW V2G experimental prototype is built and tested to verify the feasibility and stability of the proposed strategies. The prototype offers an excellent dynamic and steady-state response in stand-alone and grid-tie modes.

Recent Trends in Wearable Electronic Textiles (e-Textiles): A Mini Review

Wearable electronic textiles (e-textiles) have the ability to sense, respond, and adjust in multiple environmental stimuli, which can interact with the human brain's capability for cognition, reasoning, and activation. Moreover, they have the ability to generate and store energy, keep track of the wearer's health, and react to varying situations. Conductive polymers, metal-wrapped yarns, as well as, carbon nanotubes with silver, copper, and gold nanoparticles are used in a variety of yarn structures to design circuits, switches, and fabrics directly. Knitting, stitching, embroidery, and other integration techniques are used to combine electronic components and electrical interconnects to develop flexible electronic clothing and smart wearables. For this purpose, controlled sensors, actuators, conductive embroidered or printed fabric, planer yarn, data transfer devices, conductive inks, electromagnetic shielding, power supply, and other components are incorporated in e-textiles design. Despite the progress made so far, wearable e-textiles still, lack the required performance and device features along with the issues related to complex fabrication techniques, end-of-life processing and sustainability. Hence, this review aims to discuss the recent developments, which address the future challenges concerning electronic (e-textiles).

Follow the Grid, Follow the Violence: The Project for a Transregional Mediterranean Electricity Ring

This paper draws on the project for a Mediterranean electricity ring to study questions of structural violence and exclusion. It focuses on how forms of containment at different sites of the envisaged ring connect with energy connectivities enabled by transregional electricity flows. It illustrates how seemingly local manifestations of violence at different nodes of the ring are not a testimony to the incompleteness of ongoing (energy) infrastructure projects, but instead an interconnected and distinct part of the latter. Specifically, it discusses the greenwashing of authoritarian power and colonial occupation, extractivism, climate, and anti-refugee violence. While trans-Mediterranean electricity interconnections enable the greater integration of renewables and may lead to more sustainable energy futures, they are also illustrative of the desire to find new ways to bypass and/or contain Arab populations, as well as refugees trying to cross the Mediterranean. The project for a transregional Mediterranean electricity ring both creates new connectivities and reinforces violent forms of containment while staging European sovereignty in and beyond the Mediterranean. It hides and thereby reproduces (colonial) violence behind a façade of common futures and interconnectivity for all, which reveals itself as deeply exclusionary and Eurocentric.

Capillary Self‐Assembly Register Microspheres to Fabricate Anisotropic Conductive Film Used for Ultra‐Fine Pitch Stable Electrical Interfacing Interconnection

AbstractThe trend to integrate more electronic components in a limited space range motivates the development of advanced electronic packaging. Conventional electronic packaging is difficult to perform in stable interfacing interconnection pitch below 7 µm due to the possibility of short‐circuit problems. Herein, a kind of anisotropic conductive film (μ‐ACF) containing periodically arranged conductive microspheres for microscale pitch electrical interfacing interconnection is developed. The periodic arrangement can avert the contact of conductive microspheres, thus enabling stable interconnection with a pitch as small as 5 µm. By coating conductive microspheres with a layer of silicon insulation, the pitch can be further reduced to 3 µm, which can prevent the formation of conductive pathways between electrodes even if they come into contact with each other. Such high‐quality arrangement is achieved by lithography and capillary self‐assembly method, which is expected to be used in high‐throughput production. Thanks to the delicate design, the μ‐ACF can achieve a low contact resistance of 4.62 mΩ mm−2 and a spatial resolution of 3 µm without short‐circuit failure. The spatial resolution can be further improved by adjusting the size of conductive microspheres, which is conducive to the development of highly integrated devices.

Effects of anthropogenic magnetic fields on the behavior of a major predator of the intertidal and subtidal zones, the velvet crab Necora puber

With the progress of the offshore renewable energy sector and electrical interconnection projects, a substantial rise in the number of submarine power cables is expected soon. Such cables emit either alternating or direct current magnetic fields whose impact on marine invertebrates is currently unknown and hardly studied. In this context, this study aimed to assess potential short-term exposure (30 min) effects of both alternating and direct magnetic fields of increasing intensity (72–304 μT) on the behavior of the high-ecological value velvet crab (Necora puber). Three experiments were designed to evaluate whether the strongest magnetic field intensities induce crabs’ attraction or repulsion responses, and whether foraging and sheltering behaviors may be modified. We extracted from video analyses several variables as the time budgets crabs spent immobile, moving, feeding, or sheltering as well as total and maximal distance reached in the magnetic field (MF) gradient. The crabs exposed to artificial MF did not exhibit significant behavioral changes compared with those exposed to the “natural” MF. Overall, our results suggest that, at such intensities, artificial magnetic fields do not significantly alter behaviors of N. puber. Nevertheless, future studies should be conducted to examine the effects of longer exposure periods and to detect potential habituation or resilience processes.

Safety risk assessment of aircraft EWIS based on the improved combined weight and cloud model

Purpose This study aims to conduct the aircraft electrical wiring interconnection system (EWIS) safety risk assessment process abundantly and hierarchically and establish the assessment index system considering the weights and interrelationships of different levels of indices. Design/methodology/approach Due to the failure of EWIS being multifactorial, hidden and diverse, this paper divides the factors influencing the failure of EWIS into 3 primary indices, 13 secondary indices and 38 tertiary indices. Taking open circuit failure (OCF) and short circuit failure (SCF) as examples, calculate the weights of assessment indices based on the triangular fuzzy number analytic hierarchy process (TFNAHP) and triangular fuzzy number decision-making trial and evaluation laboratory (TFNDEMATEL). The cloud model (CM) divides the risk levels and obtains the safety risk assessment results. The comparative analyses of different weight calculation methods, different failure modes and different aircraft EWIS zones verify the effectiveness and practicability of the proposed method. Findings The results show that the proposed method aligns more with the actual situation than other methods. Also, the results identify key focus objects in EWIS safety risk assessment, such as the surrounding environmental factors among the primary indices having the most significant influence on OCF and SCF, the risk level of SCF being higher than that of OCF, etc. Originality/value This paper proposes a safety risk assessment index system for aircraft EWIS based on the cable parameters, surrounding environmental factors, installation and protection methods. The weight assignment is added to the assessment index system, and the safety risk assessment model is constructed by combining TFNAHP, TFNDEMATEL and CM.

Impact of impedance compensation structure in coaxial‐microstrip transition section on near‐field radiation

AbstractCoaxial‐microstrip transition sections are extensively used in radio frequency (RF) circuits, providing electrical interconnection and signal transmission. However, an antipad used for impedance compensation in the coaxial‐microstrip transition section leads to signal return path discontinuity and radiation emission. Accordingly, in this current work, the impact of impedance compensation structure on the near‐field radiation in the coaxial‐microstrip transition section was investigated by theoretical analysis and experimental testing. A 3D electromagnetic field model of a circuit board with an anti‐pad was developed to calculate the S‐parameters and radiation electric field. Based on the characteristics of the electric near‐field probe, a transfer function model was also developed to convert the radiation electric field obtained by the electromagnetic field model into the output voltage for better comparison with the test results. In addition, the effect of the rise time of the input signal on near‐electric field radiation was also studied in this work. The experimental results are in good agreement with the simulation results obtained from the transfer function model. The results of this study provide a better understanding of the electromagnetic radiation characteristics caused by the impedance compensation structure and theoretical support for compensation optimization strategy in engineering.

Magneto-transport behavior of disordered three dimensional NixCo1−x inverse opal networks

Herein we report on the magneto-transport properties of disordered three dimensional inverse opals (3D-IOs) fabricated by a standard three-probe electrodeposition technique into the interstices of porous membranes made of 150 nm diameter self assembled poly(methyl methacrylate) spheres. This approach has allowed the synthesis of large scale nanocomposites with exact ferromagnetic NixCo1−x alloy compositions and complex interconnected structure. Particularly, the microstructure of Co-rich 3D-IOs is consistent with the hexagonal close packed hcp texture and its corresponding magnetoresistance is explained in terms of the hcp Co magnetocrystalline anisotropy contribution. Conversely, the magnetoresistive behavior of Ni-rich 3D-IO networks is explained in terms of only their magnetostatic field. The control of these features is made possible by the reduced dimensions of necks and walls, in the 40 nm to 60 nm range, of the 3D-IO structure. Despite the disordered morphology of these 3D-IO nanoarchitectures, their microstructural and magneto-transport properties can be fine tuned due to the reduced nanoscale dimensions of the electrical interconnections. These properties have been found to be comparable to those obtained in other 3D networks, making them interesting systems for their potential use for magnetic sensing and spintronic applications.

Market Design for Cross-Border Co-Optimised Energy-Reserve Allocation

To achieve its energy goals, the European Union (EU) needs to establish a geographically large market by initially improving its cross-border electricity interconnections. The Hungarian project focuses on this topic. A geographically large market, based on imports and exports of electricity, could increase the level of competition, boost the EU’s security of electricity supply through creating alternative routes to the customers and integrate more renewables into energy markets. Electricity should, as far as possible, flow between Member States as easily as it currently flows within Member States, in order to increase sustainability potential and real competition, as well as to drive economic efficiency of the energy system. To this end, Facilitating Regional CROSS-border Electricity Transmission (FARCROSS) aims to address this challenge by connecting major stakeholders of the energy value chain and demonstrating integrated hardware and software solutions that will facilitate the “unlocking” of the resources for the cross-border electricity flows and regional cooperation. The targets of the project are to optimise the usage of the available cross-border capacity for reserve procurement while transitioning from ATC to Flow-based mechanism, to achieve simultaneous interconnector reservation for energy and balancing capacity to enable reserve market coupling and to create state-of-art technologies to materialise market coupling platforms.