Printed Wiring Boards Research Articles

Enhanced Corrosion Protection of Printed Circuit Board Electronics using Cold Atmospheric Plasma-Assisted SiOx Coatings.

The miniaturization and widespread deployment of electronic devices across diverse environments have heightened their vulnerability to corrosion, particularly affecting copper traces within printed circuit boards (PCBs). Conventional protective methods, such as conformal coatings, face challenges including the necessity for a critical thickness to ensure effective barrier properties and the requirement for multiple steps of drying and curing to eliminate solvent entrapment within polymer coatings. This study investigates cold atmospheric plasma (CAP) as an innovative technique for directly depositing ultrathin silicon oxide (SiOx) coatings onto copper surfaces to enhance corrosion protection in PCBs. A systematic investigation was undertaken to examine how the scanning speed of the CAP deposition head impacts the film quality and corrosion resistance. The research aims to determine the optimal scanning speed of the CAP deposition head that achieves complete surface coverage while promoting effective cross-linking and minimizing unreacted precursor entrapment, resulting in superior electrical barrier and mechanical properties. The CAP coating process demonstrated the capability of depositing SiOx onto copper surfaces at various thicknesses ranging from 70 to 1110 nm through a single deposition process by simply adjusting the scanning speed of the plasma head (5-75 mm/s). Evaluation of material corrosion barrier characteristics revealed that scanning speeds of 45 mm/s of the plasma deposition head provided an effective coating thickness of 140 nm, exhibiting superior corrosion resistance (30-fold) compared to that of uncoated copper. As a proof of concept, the efficacy of CAP-deposited SiOx coatings was demonstrated by protecting an LED circuit in saltwater and by coating printed circuits for potential agricultural sensor applications. These CAP-deposited coatings offer performance comparable to or superior to traditional conformal polymeric coatings. This research presents CAP-deposited SiOx coatings as a promising approach for effective and scalable corrosion protection in miniaturized electronics.

Corrosion-Resistant Ultrathin Cu Film Deposited on N-Doped Amorphous Carbon Film Substrate and Its Use for Crumpleable Circuit Board.

Copper (Cu) is widely used as an industrial electrode due to its high electrical conductivity, mechanical properties, and cost-effectiveness. However, Cu is susceptible to corrosion, which degrades device performance over time. Although various methods (alloying, physical passivation, surface treatment, etc.) are introduced to address the corrosion issue, they can cause decreased conductivity or vertical insulation. Here, using the nitrogen-doped amorphous carbon (a-C:N) thin film is proposed as a substrate on which Cu is directly deposited. This simple method significantly inhibits corrosion of ultrathin Cu (<20nm) films in humid conditions, enabling the fabrication of ultrathin electronic circuit boards without corrosion under ambient conditions. This study investigates the origin of corrosion resistance through comprehensive microscopic/spectroscopic characterizations and density-functional theory (DFT) calculations: i) diffusion of Cu atoms into the a-C:N driven by stable C-Cu-N bond formation, ii) diffusion of N atoms from the a-C:N to the Cu layer heading the top surface, which is the thermodynamically preferred location for N, and iii) the doped N atoms in Cu layer suppress the inclusion of O into the Cu lattice. By leveraging the ultrathinness and deformability of the circuit board, a transparent electrode and a crumpleable LED lighting device are demonstrated.

Tailoring three-dimensional conjugated microporous polymers for photo-enhanced gold extraction

Extracting gold from discarded electronic devices can alleviate the growing environmental problems associated with e-waste and provide a sustainable avenue for the secondary utilization of precious metal resources. Unfortunately, viable green recycling methods have not yet been implemented beyond the large-scale incineration of electronic circuit boards, mainly due to the lack of emerging strategies for efficient gold extraction. It is foreseeable that using green photocatalytic technology to extract gold can provide alternative to existing strategies. Herein, we explore the application of D-π-A-type thiazole-functionalized three-dimensional (3D) conjugated microporous polymer (CMP) (BTD-TEP) for photo-enhanced gold extraction from e-waste. With a large specific surface area, abundant high-affinity sites, good chemical stability, and excellent photocatalytic activity, BTD-TEP can be used as an advanced platform for selective extraction and photocatalytic reduction of gold, thus exhibiting a breakthrough gold recovery capacity (3217.8 mg/g). In the dark, BTD-TEP can selectively extract gold through thiazole motifs integrated on the highly accessible 3D skeleton. Meanwhile, the construction of a highly conjugated 3D D-π-A framework significantly increases the exposure of the catalytic center, enhances the photocatalytic activity of BTD-TEP, and allows for an additional gold photocatalytic reduction process under visible light, which greatly improves the recovery capacity and kinetics.

Development of Materials for Printed Wiring Boards for High-Speed Communication

Development of Materials for Printed Wiring Boards for High-Speed Communication

Design of Dry Friction Damper to Reduce Vibration Impacts to Circuit Cards at Critical Frequencies

Design of Dry Friction Damper to Reduce Vibration Impacts to Circuit Cards at Critical Frequencies

An artificial intelligence-based approach for identifying the in-plane orthotropic mechanical properties of electronic circuit boards

The finite element modeling of electronic boards is a challenging task due to the complexity of the multi-component board structure. Hence, it is acceptable to attain equivalent orthotropic in-plane mechanical properties and use them throughout the finite element analysis (FEA) simulations. This paper aims to present an artificial intelligence-based methodology, using the artificial neural networks (ANNs), to estimate the in-plane mechanical properties of the printed circuit boards (PCB). In this methodology, the ANN technique used FEA data to find the relationship between the first 10 natural frequencies and the mechanical properties, that is, modulus of elasticity, Poisson’s ratio and the shear modulus, of the test board. Subsequently, the experimentally derived natural frequency data is then imported to the ANN model to identify the equivalent orthotropic properties. The ANN-predicted properties are plugged back into FEA and provided natural frequencies and mode shapes that are in great match with experimental results.

Exploring the use of natural fiber-reinforced polymer composites in electronic circuit boards

Sustainable banana fiber has become potential alternative reinforcement materials instead of synthetic fibers for the development of the polymer composites. These natural fiber-reinforced polymer composites can be utilized for numerous applications. The current study aims to fabricate the epoxy/banana fiber composites under varying fraction of banana fibers. Compression molding process was employed to fabricate the composites since it is frequently used for production of large-scale composite parts like automotive components. Various weight percentages of banana fiber (50%, 60%, 70%, and 80% by weight) and epoxy (50%, 40%, 30%, and 20% by weight) were utilized for the development of the composites. Results revealed that the combination of the epoxy (40 wt. %)/banana fiber (60%) has the higher tensile strength of 22.67 MPa, flexural strength of 39.56 MPa, impact strength of 2.97 kJ/m2, and Barcol hardness of 35.24 among the various combinations of the epoxy and banana fiber composites. This work highlights the viability of sustainable materials within the materials engineering field, promoting the development of eco-friendly alternatives in composite fabrication.

Novel Space-Vector PWM Schemes for Enhancing Efficiency and Decoupled Control in Quasi-Z-Source Inverters

This paper investigates the development of pulse width modulation (PWM) schemes for three-phase quasi-Z-source inverters (qZSIs). These inverters are notable for their voltage boost capability, built-in short-circuit protection, and continuous input current, making them suitable for low-voltage-fed applications like photovoltaic or fuel cell-based systems. Despite their advantages, qZSIs confront challenges such as increased control complexity and a larger number of passive components compared to traditional voltage source inverters (VSIs). In addition, most existing PWM schemes for qZSIs lack the capability for independent control of the amplitude modulation index and duty cycle, which is essential in closed-loop applications. This study introduces innovative space-vector PWM (SVPWM) schemes, addressing issues of independent control, synchronization, and unintentional short-circuiting in qZSIs. It evaluates several established continuous and discontinuous PWM schemes, and proposes two novel decoupled SVPWM-based schemes that integrate dead time and in which the shoot-through occurrence is synchronized with the beginning of the zero switching state. These novel schemes are designed to reduce switching losses and improve qZSI controllability. Experimental validation is conducted using a custom-developed electronic circuit board that enables the implementation of a range of PWM schemes, including the newly proposed ones. The obtained results indicate that the proposed PWM schemes can offer up to 6.8% greater efficiency and up to 7.5% reduced voltage stress compared to the closest competing PWM scheme from the literature. In addition, they contribute to reducing the electromagnetic interference and thermal stress of the related semiconductor switches.

Multi-Modal Urban Traffic Transfer Schedule Timetable Bi-Objective Optimization: Model, Algorithm, Comparison, and Case Study

The optimization of the connection between urban rail transit and the bus is an essential issue that benefits passenger travel and the urban structure and has social benefits, which can be realized by reasonably adjusting the bus departure schedule. This study is necessary because the development status quo of China’s urban transportation network planning is unreasonable, travel efficiency is not high, and operating costs are high. This paper sets up the decision variables of bus departure time and departure interval at each station, establishes a dual-objective optimization model with the minimum schedule change and the minimum transfer time, and studies the application of the augmented Chebyshev algorithm in the dual-objective optimization model. Secondly, based on the Shenzhen metro and public transportation integrated circuit card data, the case analysis uses the generalized Chebyshev algorithm and the non-dominated sorting genetic algorithm, respectively. The optimization results show that using the improved augmented and generalized Chebyshev algorithm in the bus schedule alteration time within a reasonable range can maximize the total transfer time, which compared with the original scheme is shortened by 68.06%. In contrast, genetic algorithms will make the complete bus schedule alteration prominent, and the whole transfer time is substantially increased. The results show that the improved augmented generalized Chebyshev algorithm is more suitable for solving the dual-objective rail transit connection problem.

Evaluation of Metals in Printed Wiring Boards of Selected Discarded Mobile Phones in Nigeria

Obsolete mobile phones form a major component of the e-waste stream. The Printed wiring boards (PWBs) of mobile phones are packed with economic and toxic metals. Regulatory bodies such as Restriction of Hazardous Substances (RoHS) directives regulate the amount of these toxic metals in electrical and electronic equipment. This study is aimed at evaluating selected critical metals present in PWBs of three popular brands of discarded mobile phones used in Nigeria to understudy the behaviour of original equipment manufacturers (OEMs) regarding toxicity, economic potentials, and level of compliance with international initiatives by regulatory bodies to reduce the level of toxic metals in electronic equipment. PWBs obtained from 60 discarded mobile phones of 3 popular mobile phone brands used in Nigeria were chopped into smaller particles, extracted according to EPA 3050B method, and analysed using the Inductive Coupled Plasma-Optical Emission Spectrometry technique. It was observed that Mn, Fe, Zn, and Cu, had the highest concentration range across all brands studied. Notable toxic metals such as Pb, Cd, Cr, and As have mean and standard deviation values of 0.43±0.38 mg/kg, 0.62±0.160 mg/kg, 5.16±1.06 mg/kg, and 84.97±13.83 mg/kg respectively. Economic metals: Cu, Ag, and Au had mean and standard deviation values of 80.37±16.89 mg/kg, 2.12±0.43 mg/kg, and 0.95±0.19 mg/kg respectively. Results from the study indicate that PWBs of mobile phones are a perfect secondary source of a large variety of metals vital for the recycling industry. Also, the low levels of toxic metals suggest that some OEMs are already adopting the 'design-for-environment' option. Therefore, PWBs studied seem eco-friendly; however, need to be handled with care as there are still some toxic metals of concern not determined in this study.

Freeze Drying of Organically Modified Layered Silicates as Key Step to Improve the Barrier Properties of Organic Coatings for High Power Electronics Protection

AbstractOrganically modified layered silicates can be used as barrier pigments in organic coating systems to reduce the permeation of water vapor and gases, e.g., oxygen as well as harmful gases that promote corrosion. Unmodified layered silicates are not sufficient to reduce the permeation significantly. However, the arrangement and orientation of the particles have an enormous impact on the later performance in the barrier film. In organic solvents or non‐aqueous polymer matrices the non‐modified layered silicates cannot exfoliate adequately. The organic modification influences the layer spacing and the compatibility to organic solvents. Layered silicates are modified with dodecylamine to enhance the spacing layer. The spacing layer is enhanced by 55% caused by the organic modification as it is commonly known. In contrast to previous work freeze drying of the organically modified layered silicates improved the particle distribution and by this barrier properties significantly. The modified particles reduce the diffusion of water and oxygen by ≈99.6% and 97.2%, respectively. The corrosive gas test of electronic circuit boards shows no growth of dendrites and no failure of the electronics in contrast to protective coating without the layered silicates.

Secure Transactions in a Chip: A Contemporary Review of Smart Card Innovations

Smart card technology has emerged as a powerful tool in the field of secure identification, authentication, and transaction processing. This abstract provides a comprehensive overview of smart card technology, highlighting its key features, applications, and benefits. Smart cards, also known as integrated circuit cards, are portable devices that incorporate a microprocessor and memory to securely store and process information. These cards have revolutionized various industries by enabling secure access control, secure payment transactions, and secure storage of sensitive data. The abstract begins by exploring the fundamental components and architecture of smart cards. It delves into the different types of smart cards, such as contact-based and contactless cards, and explains the communication protocols employed in their operation. Furthermore, the abstract discusses the extensive range of applications where smart cards have found widespread adoption. These applications include identification cards, payment cards, healthcare cards, transportation cards, and more. The abstract highlights the advantages of using smart cards in each of these domains, such as enhanced security, convenience, and interoperability.

Design of a Biohybrid Materials Circuit with Binary Decoder Functionality.

Synthetic biology applies concepts from electrical engineering and information processing to endow cells with computational functionality. Transferring the underlying molecular components into materials and wiring them according to topologies inspired by electronic circuit boards has yielded materials systems that perform selected computational operations. However, the limited functionality of available building blocks is restricting the implementation of advanced information-processing circuits into materials. Here, a set of protease-based biohybrid modules the bioactivity of which can either be induced or inhibited is engineered. Guided by a quantitative mathematical model and following a design-build-test-learn (DBTL) cycle, the modules are wired according to circuit topologies inspired by electronic signal decoders, a fundamental motif in information processing. A 2-input/4-output binary decoder for the detection of two small molecules in a material framework that can perform regulated outputs in form of distinct protease activities is designed. The here demonstrated smart material system is strongly modular and can be used for biomolecular information processing for example in advanced biosensing or drug delivery applications.

Adhesion Characterization and Enhancement between Polyimide-Silica Composite and Nodulated Copper for Applications in Next-Generation Microelectronics.

As the need for high-speed electronics continues to rise rapidly, printed wiring board (PWB) requirements become ever-more demanding. A typical PWB is fabricated by bonding dielectric films such as polyimide to electrically conductive copper foil such as rolled annealed (RA) copper and is expected to become thinner, flexible, durable, and compatible with high-frequency 5G performance. Polyimide films inherently feature a higher coefficient of thermal expansion (CTE) than copper foils; this mismatch causes residual thermal stresses. To attenuate the mismatch, silica nanoparticles may be used to reduce the CTE of PI. A nodulated copper surface can be used to enhance the Cu/PI adhesion by additional bonding mechanisms that could include a type of mechanical bonding, which is a focus of this study. In this investigation, a 90° peel test was used to measure the peel strength in copper/polyimide/copper laminates containing nodulated copper and polyimide reinforced with 0, 20, and 40 wt % silica nanoparticles. The influence of silica nanoparticles on the peel strength was quantitatively evaluated. Laminates incorporating polyimide films lacking silica nanoparticles had a ∼3.75× higher peel strength compared with laminates reinforced with 40% silica. Their failure surfaces were analyzed by using scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy to identify the mode of failure and to understand bonding mechanisms. The key bonding mechanism, mechanical interlocking, was achieved when the polyimide surrounded or engulfed the copper nodules when the laminate was created. Post-testing failure surface analysis revealed the presence of copper on the polyimide side and polyimide on the copper side, indicating mixed mode failure. An analytical model was developed to determine the impact of applied pressure, temperature, and time on the polyimide penetration and mechanical interlocking around the copper nodules. The model was validated by measuring the peel strength on another set of specimens fabricated using increased temperature and pressure that showed a 3× increase in peel strength compared to lower temperature/pressure processing conditions. This enhanced adhesion resulted from the lower polymer material viscosity at higher temperatures, which fosters deeper and more complete penetration around the copper nodules during processing at higher pressures for longer durations. The methodology of combining peel testing, viscosity and CTE measurement, SEM/EDX, surface chemical analysis, and penetration depth calculation developed herein enables the calculation of the desired processing parameters to enhance functionality and improve adhesion.

Evaluation and Analysis of Printed Wiring Boards with Micro Via Connections: Advance in Methods Using Micro-resistance Measurement

Evaluation and Analysis of Printed Wiring Boards with Micro Via Connections: Advance in Methods Using Micro-resistance Measurement

Exploring Hybrid Models For Short-Term Local Weather Forecasting in IoT Environment

This paper explores using and hybridizing simple prediction models to maximize the accuracy of local weather prediction while maintaining low computational effort and the need to process and acquire large volumes of data. A hybrid RF-LSTM model is proposed and evaluated in this research paper for the task of short-term local weather forecasting. The local weather stations are built within an acceptable radius of the measured area and are designed to provide a short period of forecasting - usually within one hour. The lack of local weather data might be problematic for an accurate short-term valuable prediction in sustainable applications like agriculture, transportation, energy management, and daily life. Weather forecasting is not trivial because of the non-linear nature of time series. Thus, traditional forecasting methods cannot predict the weather accurately. The advantage of the ARIMA model lies in forecasting the linear part, while the SVR model indicates the non-linear characteristic of the weather data. Both non-linear and linear approaches can represent the combined model. The hybrid ARIMA-SVR model strengthens the matched points of the ARIMA model and the SVR model in weather forecasting. The LSTM and random forest are both popular algorithms used for regression problems. LSTM is more suitable for tasks involving sequential data with long-term dependencies. Random Forest leverages the wisdom of crowds by combining multiple decision trees, providing robust predictions, and reducing overfitting. Hybrid Random forest-LSTM potentially leverages the robustness and feature importance of Random Forest along with the ability of LSTM to capture sequential dependencies. The comparison results show that the hybrid RF-LSTM model reduces the forecasting errors in metrics of MAE, R-squared, and RMSE. The proposed hybrid model can also capture the actual temperature trend in its prediction performance, which makes it even more relevant for many other possible decision-making steps in sustainable applications. Furthermore, this paper also proposes the design of a weather station based on a real-time edge IoT system. The RF-LSTM leverages the parallelized characteristics of each decision tree in the forest to accelerate the training process and faster inferences. Thus, the hybrid RF-LSTM model offers advantages in terms of faster execution speed and computational efficiency in both PC and Raspberry Pi boards. However, the RF-LSTM consumes the highest peak memory usage due to being a combination of two different models.

Mekanik Tahrikli Rastgele Kısa Desen Yapan Makine Prototipi

One of the important producers of the industrial industry in our country is the textile sector. The importance of the textile industry for our country is growing day by day with increasing production and employment. In order to keep up with this growth, manufacturers need to go beyond their existing systems, show their differences and make the right innovations in their production. Considering these values, changes to be made in the yarn structure or dyeing process come to the fore. In this study, the dyeing process is discussed. Weaving and home textiles, which are an important part of the textile industry, have a wide market. There are different dyeing systems that have an important market for the products made in these areas. Spaced and smart painting, which are among these painting systems, do not meet the needs in the desired direction. A new machine design is needed to provide the desired features. In the study conducted in this direction; A commercially unavailable machine has been implemented, designed and manufactured to generate random short patterns with mechanical drive. In project scope; First of all , the paint stand to be integrated into the system was designed . Different yarn lifters and godet systems have been designed. Paint container, drive system and electronic panel are also mounted on the system. In addition, new software has been developed within the scope of the project to provide automatic control of the system. Studies were carried out with PLC and Arduino electronic circuit board. In the first stage, motor driver circuits were designed with PLC and Arduino. Then, with the software loaded on the PLC and Arduino processor board, the frequency values to be given to the inverter were started by changing the threshold ranges we wanted. Lifters and painting cylinders are connected to each other so that the same sequence is not repeated. Thus, in this study carried out in line with the needs, both a new machine and a new textile product with different dye patterns emerged.

Empirical analysis of power side-channel leakage of high-level synthesis designed AES circuits

&lt;span&gt;Many internet of things (IoT) devices and integrated circuit (IC) cards have been compromised by side-channel attacks. Power-analysis attacks, which identify the secret key of a cryptographic circuit by analyzing the power traces, are among the most dangerous side-channel attacks. Gen-erally, there is a trade-off between execution time and circuit area. However, the correlation between security and performance has yet to be determined. In this study, we investigate the cor-relation between side-channel attack resistance and performance (execution time and circuit area) of advanced encryption standard (AES) circuits. Eleven AES circuits with different performances are designed by high-level synthesis and logic synthesis. Of the eleven AES circuits, six are circuits with no side-channel attack countermeasures and five are circuits with masking countermeasures. We employ four metrics based on a T-test to evaluate the side-channel attack resistance. The results based on the correlation coefficient show the correlation between side-channel attack resistance and performance. The correlation varies according to four metrics or masking countermeasure. We argue that designers should change their attitudes towards circuit design when considering security.&lt;/span&gt;

Synergistic red dominancy over green upconversion studies in PbZrTiO3: Er3+/Yb3+ phosphor synthesized via two different modified technique and flexible thin-film thermometer demonstration on C1: PbZrTiO3 @PDMS substrates

Owing to its efficient wide range sensing using a noncontact mechanism with a decimal accuracy level, quick, non-invasive temperature sensors utilizing upconversion (UC) phosphor were examined. These sensors are perfect for cutting-edge applications such as measuring the intracellular temperature and identifying microelectronic issues. It may be possible to modify the performance of phosphor temperature sensors through nanoscale engineering. Despite were potential, it has been discovered that modern nanothermometers are ineffective in maintaining stability over a wide temperature range. Motivated by previous studies on efficient UC based solar cell demonstrations of Er3+/Yb3+: PbZrTiO3 (lead zirconate titanate) phosphors, the UC properties of Er3+/Yb3+: PbZrTiO3 for a wide range of temperature sensing and practical thermometer applications have been investigated. The UC emission properties of the Er3+/Yb3+: PbZrTiO3 phosphors synthesized via different routes, with the same dopant concentration, were compared. We have also investigated the formation of two different crystal symmetry, and an approach for the fine-tuning of the emission from the green to the red region upon changing the synthesis technique. The strategy of choosing an optimized synthesis route, based upon structural investigations, could be a way forward where dopant modification in phosphors is ruled out. Based on the UC optimization, the green and red dominant phosphors under 980 nm excitation with different pulse widths and power densities or at different temperatures were studied; the possible mechanisms were discussed in detail. The sensitivity of Er3+/Yb3+: PbZrTiO3 was independent of the pumping laser characteristics since it was essentially consistent when utilising both continuous wave and laser pulse width modulation or varying power densities. To assess the temperature of the microelectronic components, a flexible thin-film thermometer was made of Er3+/Yb3+: PbZrTiO3 on a polyDiMethylSiloxane substrate. This thermometer shows great repeatability and can measure the temperature of an electronic circuit board correctly. The findings suggested that the current non-contact UC temperature sensor might potentially replace conventional thermometers because of its steady green emission over a wide temperature range (313–673 K) and thermometric sensitivity.

Applicability of Weibull distribution in Generating Model for Evaluating Lifespan Closed Circuit Television System (CCTV)

CCTV is an expedient tool for monitoring and investigating. Since it can record emergency and routine events in memory of the electronic circuit board. However, in the process of operating CCTV, it is necessary to carry out a sampling inspection on its lifetime to predicate its availability and reliability. According to previous literature, most of the parameter estimation methods used only one parameter estimation method, which is not sufficient for identifying two explicit parameters of Weibull distribution. Moreover, the bad parameter estimation method cannot achieve reliable analysis results. Therefore, this paper presented the four methods of estimation in both graphical and analytical methods for estimating parameters of Weibull distribution. These methods have measured the accuracy by using mean square error (MSE). In addition, the real data set confirmed that there is the Weibull distribution by using the Kolmogorov-Smirnov test. The simulation results found that the maximum likelihood method (MLM) can outperform the other estimator because it can provide a minimum MSE, there is an optimal parameter in which the shape is 4.3881 and the scale is 86.8207. Finally, the two optimal parameters are applied to real data sets of the CCTV. As a result, the optimal parameter fits with real data sets, and it can evaluate the lifespan of CCTV by using the mean time to failure (MTTF) as 6.6 years.