Through Holes Research Articles

New results of the technological prototype of the CALICE highly granular silicon tungsten calorimeter

An extended version of the CALICE silicon–tungsten ECAL, with 15 active layers, was tested in November 2021 at the DESY beam test facility. Respectively with the previous design, it featured some complete layers with a thin PCB design, and a new compact DAQ handling 15 layers in a common set. The noise, self-trigger performance and response to punch-though electrons, without tungsten absorbers, was evaluated for each of the 15,360 channels, using an improved procedure. Showers of low-energy electrons (1 to 5 GeV) have been recorded in two configuration of absorber, and are being analysed. Some preliminary results will be shown here.

Reconfigurable Electrical Networks within a Conductive Hydrogel Composite.

Soft materials that exhibit compliance, programmability, and reconfigurability can have a transformative impact as electronic skin for applications in wearable electronics/soft robotics. There has been significant progress in soft conductive materials; however, achieving electricallycontrolled and reversible changes in conductivity and circuit connectivity remains challenging. To overcome this limitation, asoft material architecture with reconfigurable conductive networks of silver flakes embedded within a hydrogel matrix is presented. The conductive networks can be reversibly created/disconnected through various stimuli, including current, humidity, or temperature. Such stimuli affect electrical connectivity of the hydrogel by controlling its water content, which can be modulated by evaporation under ambient conditions (passive dehydration), evaporation through electrical Joule heating (active dehydration), or absorption of additional water (rehydration). The resulting change in electrical conductivity is reversible and repeatable, endowing the composite with on-demand reconfigurable conductivity. To highlight this material's unique properties, it is shown that conductive traces can be reconfigured after severe damage and revert to lower conductivity after rehydration. Additionally, a quadruped robot is demonstrated that can respond to stimuli by changing direction following exposure to excess water, thereby achieving reprogrammable locomotion behaviors.

Wireless-controlled cubic neural stimulator for free-moving animals.

An electrical stimulator transmitting information into selected neural circuits is a promising approach for neural prostheses or animal robots. However, traditional stimulators are based on rigid printed circuit board (PCB) technology; technological limitations hindered the development of stimulators, especially for experiments involving free-moving subjects. Here we described a small (1.6 × 1.8 × 1.6 cm), lightweight (4 g, including a 100 mA h lithium battery) and multi-channel (eight unipolar or four bipolar biphasic channels) cubic wireless electrical stimulator exploiting flexible PCB technology. In comparison with the traditional stimulator, an appliance of both flexible PCB and cube structure makes it smaller and lighter, and enhances its stability. Stimulation sequences can be constructed with 100 selectable current levels, 40 selectable frequency levels and 20 selectable pulse-width-ratio levels. Moreover, the distance of wireless communication can reach approximately 150 m. Both in vitro and in vivo results have demonstrated functionality of the stimulator. The feasibility of remote pigeon's navigation using the proposed stimulator was successfully verified.

Phosphorus-Containing Flame-Retardant Benzocyclobutylene Composites with High Thermal Stability and Low CTE.

As a component of printed circuit substrate, copper clad laminate (CCL) needs to meet the performance requirements of heat resistance, flame retardancy, and low coefficient of thermal expansion (CTE), which, respectively, affects the stability, safety, and processability of terminal electronic products. In this paper, benzocyclobutylene (BCB)-functionalized phosphorus-oxygen flame retardant composites were prepared through introducing the BCB groups, and the performance was researched by thermogravimetric analysis, microcombustion calorimetry, and thermomechanical analysis. The research results show that these phosphorus oxide compounds containing BCB groups show good thermal stability and low total heat release (THR) after thermal curing, and the more BCB groups on the phosphorus oxide monomers, the better the thermal stability and flame retardancy of cured resins. The Td5 and THR of the composite (M3) are as high as 443 °C and 23.1 kJ/g, respectively. In addition, the CTE of M3 is as low as 16.71 ppm/°C. Introduction of BCB groups which can be crosslinked through heat to improve the thermal stability, flame retardancy, and reduced CTE of traditional organophosphorus flame retardant materials. These materials are expected to be good candidates for CCL substrates for electronic circuits.

Engineering Solutions Live

On 23rd March at the British Motor Museum, Gaydon, Engineering Solutions Live will once again open its doors. Featuring FAST Live, Engineering Materials Live and PCB Design all under one roof in a one-day, one-stop shop format, the event promises once again to deliver for design engineers.

Lantern‐Inspired On‐Skin Helical Interconnects for Epidermal Electronic Sensors

AbstractEpidermal electronics have been attracting considerable attention due to their various potential applications in human‐computer interaction and health monitoring. However, because of the lack of a self‐adhesive and stable interconnect method between epidermal electronic sensors and rigid circuit boards, there remain difficulties in detecting body signals accurately by epidermal electronic sensors in daily life. Here, a 3D helical on‐skin interconnect is first introduced for epidermal electronics sensors. Inspired by the structure of the accordion lantern, the interconnect is composed of two electrospinning polyurethane (PU) fiber films and a helical metal fiber. The helical metal fiber acts as a stable conductor with stretchability, and the PU fiber film with polydimethylsiloxane provides a self‐adhesive substrate. Mechanical simulations and tests prove that the proposed interconnect can laminate conformally and unobtrusively onto human skin with excellent electrical stability (less than 0.5% electrical resistance change upon 100% elongation). Furthermore, based on the proposed interconnect, an all‐in‐one sensor‐interconnect design is presented, which endows the epidermal electronic systems with anti‐motion interference capability. A gesture identification wristband system realized by a single all‐in‐one strain sensor is demonstrated. Besides, a wireless on‐skin system that accurately monitors dynamic 12‐lead electrocardiographic is successfully built using all‐in‐one electrodes.

Achieving Good Bonding Strength of the Cu Layer on PET Films by Pretreatment of a Mixed Plasma of Carbon and Copper.

Cu layers were fabricated on PET films with and without pretreatment by a mixed plasma composed of carbon and copper using a magnetron sputtering technique for potential application as the flexible copper-clad laminate (FCCL) in 5G technology. In order to evaluate the effect of carbon plasma on the composited layer, the graphite target current was adjusted from 0.5 to 2.0 A. The microstructures and properties of Cu layers on PET films with different treatments were measured by an X-ray powder diffractometer, X-ray photoelectron spectroscope, Raman spectroscope, scanning electron microscope, transmission electron microscope, scratching test, indentation test, and four-probe detector. The results showed that the organic polymer carbon structure on the surface of PET films was changed to inorganic amorphous carbon due to the effect of the carbon plasma. At the same time, the active free radicals formed in the transition process react with metal copper ions to form organometallic compounds. Under the treatment of a mixed plasma of carbon and copper, the C/Cu mixed layer was formed on the PET film at the top of the substrate. Due to the presence of C/Cu mixed interlayers, the bonding strengths between the final Cu layers and the PET film substrates were improved, and the strongest bonding strength appeared when the graphite target current was 1.0 A. In addition, the presence of the C/Cu mixed interlayer enhanced the toughness of the Cu layer on PET film. It was proposed that the good bonding strength in combination and the enhanced toughness for the Cu layer on a PET film was due to the formation of a C/Cu mixed interlayer induced by the pretreatment of a mixed plasma of carbon and copper.

Biomonitoring of heavy metal signatures in urbanized contaminated ecosystems of Southern India: A case study using raptor, Athene brama

Background: Heavy metals remain tenacious in the environment which further leads to emerging bioaccumulation, rising through the food chain. Birds are great environmental sentinels that can spot even the smallest changes. The aim of this study was to determine the quantity of heavy metals, specifically Ni, copper (Cu), aluminum (Al), titanium (Ti), and Se, in the feathers, liver, kidney, muscle, and bones of spotted owlets (Athene brama), which were opportunistically collected from a variety of contaminated ecosystems in the urbanized landscapes of Visakhapatnam on India’s East Coast. Methods: Opportunistic sample collection was done followed by necropsy. Following standard protocols, organic samples were digested by adding 10 mL HNO3 , 5 mL of HClO4 , and 2 mL of H2 O2 to eliminate the excess organic matter. Results: Based on the GIS data, raptors were shown to occur in production landscapes and mostly in urban spaces, and currently, are under several anthropogenic threats. The findings showed that the sequence of heavy metal concentrations was Ti>Al>Cu>Ni>Se, but the tissues of birds in which metals accumulated are in the following order: liver>kidney>bones>muscle. The tissues of A. brama showed the signs of significant concentrations of Ti and Al. The results obtained were analyzed using Kruskal-Wallis non-parametric test. Conclusion: Heavy metal studies on various matrices of the environment have been performed over time with certain metals either neglected or not being documented properly. The main finding of this study is the first report of Ti and Al in bird species from India as there is a lacuna in this context.

Absenteeism and Self-Efficacy on 3D Schematic Drawing and PCB Design Course

Absenteeism and Self-Efficacy on 3D Schematic Drawing and PCB Design Course

Flexible Hybrid Electronics via Near‐Infrared Radiation‐Assisted Soldering of Surface Mount Devices on Screen Printed Circuits

AbstractThe development of flexible hybrid electronics (FHEs) with high‐throughput integration of electrical components onto digitally printed circuits has a wide range of applications, such as asset tracking, wearable electronics, and structural health monitoring. However, one of the major challenges with FHEs is the process of soldering the electrical components onto a printed circuit while having minimal thermal damage to the printed traces and their temperature‐sensitive polymeric substrates. Here, the possibility of utilizing near‐infrared (NIR) technology as a nondestructive photonic approach for rapid soldering and mounting electrical components onto printed circuits while keeping the polymer substrate at a relatively low temperature during the soldering process is investigated. Results of this systematic study show that FHEs prepared with the optimized NIR processing conditions produce the desired reflow of solder with effective electrical connection and metallic bonding of electrical components onto the conductive traces with excellent mechanical stability (no failure even after 1000 cycles of bending). Furthermore, using this technique and as a proof of concept, the fabrication of a wearable FHE device that provides a remote assessment of the wound exudate absorption in dressings and notifies caregivers of the appropriate time to change the dressing is demonstrated.

Autoencoder-extended Conditional Invertible Neural Networks for Unfolding Signal Traces

The reconstruction of cosmic ray-induced air showers from measurements of radio waves constitutes a major challenge. In this work, we focus on recovering the full three-dimensional electromagnetic field from two recorded signal traces of an antenna station covering two horizontal polarization directions. The simulated field is folded by a direction and frequency-dependent characteristic antenna response pattern, resulting in voltage signal traces as a function of time. Both signal traces are contaminated by simulated background noise. We use conditional Invertible Neural Networks (cINNs) to learn posterior distributions, from which the most likely electromagnetic field given a measured signal trace can be inferred. To improve robustness, we extend the method with an autoencoder by reducing the parameter phase space and decoupling the cINN from specific data shapes. Thereby, each signal trace is condensed into a small number of abstract parameters in the latent space on which the cINN operates. The presented method shows promising results and can be transferred to other unfolding problems where the recovery of the pre-measurement state is of interest.

Recent progress on polyphenylene oxide-based thermoset systems for high-performance copper-clad laminates

With the rapid development of electronic information technology in the 5G era towards high integration, short propagation delay, and elevated assembly temperatures, more academic and industrial attention has been focused on high-frequency and high-speed copper-clad laminates (CCLs). Compared with conventional polymeric matrices, thermoset polyphenylene oxide (PPO) has become one of the most attractive resins applied in high-performance CCLs (HPCCLs) because of its excellent comprehensive properties, including outstanding dielectric properties, high thermal stability, great processibility, and low moisture absorption, etc. This review focuses on the history of the development of PPO prepolymers/oligomers, PPO-based thermoset resin systems, and PPO/inorganic filler composites to optimize the dielectric constant, dielectric loss, thermal conductivity, coefficient of thermal expansion, and mechanical properties. Moreover, some current challenges of PPO-based thermoset systems have been identified, such as developing feasible solutions to ensure the anti-aging properties for long-term reliability under harsh environments of high temperature, high humidity, and even high-frequency electromagnetic radiation. In general, more in-depth investigations of PPO-based thermoset systems for HPCCLs are required in the future.

Constrained layer damping concept used on isolated gym floors. Better than Concrete?

As the global fitness trends continues in a post-pandemic world, intra-building disruptions from high-energy fitness create serious acoustical challenges. Solutions from simple roll-out mats and rubber tiles to concrete floating floors supported by spring jack-up isolators are used to achieve acoustical separation for gyms. Understanding the sources of sound and vibration produced in fitness environments and finding effective solutions was a journey that CDM Stravitec began in the 1970s and this area of the acoustics industry has been intensively researched as part of the development of our range of lightweight floating floors. As part of this research, we extensively investigated how the concept of constrained layer damping (CLD) could be employed to mitigate vibration radiation through structures. In the application of fitness flooring, the CLD functions to restrict the physical movement between the rigid board layers decreases the area of influence from the impact, reduces the energy radiation through the composite panel system to its support and subsequently reduces the energy transfer into the structure. Our research has also shown that elastomeric supports balance low-resonant frequency performance to prevent energy build-up at the driving frequencies and can achieve high levels of transmission loss which are comparable to concrete based solutions.

Prospects for 21 cm Galaxy Cross-correlations with HERA and the Roman High-latitude Survey

The cross-correlation between the 21 cm field and the galaxy distribution is a potential probe of the Epoch of Reionization (EoR). The 21 cm signal traces neutral gas in the intergalactic medium and, on large spatial scales, this should be anticorrelated with the high-redshift galaxy distribution, which partly sources and tracks the ionized gas. In the near future, interferometers such as the Hydrogen Epoch of Reionization Array (HERA) are projected to provide extremely sensitive measurements of the 21 cm power spectrum. At the same time, the Nancy Grace Roman Space Telescope (Roman) will produce the most extensive catalog to date of bright galaxies from the EoR. Using seminumeric simulations of reionization, we explore the prospects for measuring the cross-power spectrum between the 21 cm and galaxy fields during the EoR. We forecast a 12σ detection between HERA and Roman, assuming an overlapping survey area of 500 deg2, redshift uncertainties of σ z = 0.01 (as expected for the high-latitude spectroscopic survey of Lyα-emitting galaxies), and an effective Lyα emitter duty cycle of f LAE = 0.1. Thus the HERA–Roman cross-power spectrum may be used to help verify 21 cm detections from HERA. We find that the shot-noise in the galaxy distribution is a limiting factor for detection, and so supplemental observations using Roman should prioritize deeper observations, rather than covering a wider field of view. We have made a public GitHub repository containing key parts of the calculation, which accompanies this paper: https://github.com/plaplant/21cm_gal_cross_correlation.

English

The development of renewable energies is essential to meet the energy demand which is growing year after year. Africa has a strong solar potential which is, however, little exploited. The development of solar photovoltaic (PV) energy will be more favored with the democratization of performance monitoring and characterization tools for PV systems. Monitoring systems are very important because they allow the monitoring of the operation and control of PV installations in order to reduce maintenance costs and avoid undesirable power supply interruptions. There are several monitoring systems, more or less efficient, proposed on the market but they are often too expensive and not adapted to all existing systems. This paper presents a low-cost electronic board for monitoring and characterizing photovoltaic systems. The designed board is based on the ATMega328 microcontroller of the open-source development platform Arduino. It is composed of four blocks that allow the acquisition of electrical and environmental parameters. The board has been tested in monitoring mode with the follow-up of a small PV solar installation. The results of these experiments are consistent with what is found in the literature. Its use in characterization mode has allowed to obtain, in real time, the current-voltage and power-voltage characteristics. Compared to the results of the IV-500W tracer, the characterization results are consistent with an RMSE of 0.81 in voltage and 0.15 in current on all points measured. The design work is completed with the PCB design on Altium designer which resulted in the Gerber file. Key words: Microcontroller, photovoltaic (PV) monitoring, PV characterization, PCB.

Facet type determination based on combined atomic force microscopy and electron backscatter diffraction.

The distribution of facet types affects the functionality of the surfaces of polycrystalline films. However, we are not aware of a previously published convenient method to determine their distribution. This work describes and demonstrates a process to determine and map the Miller indexes (hkl) of crystal facets exposed at the surfaces of polycrystalline films. To find facet types in non-trivial cases, one must know the orientation of the crystal and the direction in which the facet is facing. The method presented here combines the crystal orientations obtained with electron backscatter diffraction with the topography of the same sample area measured with atomic force microscopy. A challenging step is to transfer the data from the two instruments into a common coordinate system. The sequence of steps in the data processing is presented, with methods to verify the results. The process is illustrated with the analysis of an etched copper clad laminate (CCL) and an electroless Cu film deposited on the CCL. This example relates to facet selection in electroless and galvanic plating processes in printed circuit board production, where an uncontrolled transition from epitaxial to non-epitaxial growth can lead to surfaces with unacceptable roughness.

Robert C. Ritchie. The Lure of the Beach: A Global History.

In The Lure of the Beach, Robert C. Ritchie explores the development of beach resorts, showing how something that “started out as a modest number of individuals seeking therapeutic relief in the ocean … has morphed into a staggering phenomenon” that now dominates global culture and leisure (224). He traces the massive rise of resorts in size and popularity as they changed in character and eventually proliferated around the world. Yet Ritchie also considers the problems, both social and environmental, that these sites have provoked throughout history and continue to pose in our present and our future. Ritchie begins with the ancient Roman port of Baiae, swiftly surveys medieval Europe, and gives most of his attention to the development of resorts in England and the United States in the eighteenth, nineteenth, and twentieth centuries, while also considering the broader global dimension of this phenomenon. Ritchie highlights the social, economic, and technological factors that contributed to the rise, and sometimes the decline, of these resorts. The first beach resorts were inspired by an emergent medical consensus in the seventeenth and eighteenth centuries on the virtues of salt water and were restricted to social elites who could afford the time and costs of travel. Economic prosperity, expanded holidays, and developments in transport like steam power, motor cars, and jet planes sequentially transformed who could access the beach, driving the growth of both established and new resorts. As the numbers of visitors continually increased, resorts had to adapt to their demands and requirements. Although health benefits never disappeared as a motivation for visiting, over time entertainment became the primary purpose of most resorts. Leisure and social diversions were always part of this story, from the assembly rooms and promenades of the eighteenth century onward, but new forms came to prominence, especially in the nineteenth and early twentieth centuries, ranging from pierrots, dance venues, and music halls to piers, amusement parks, and roller coasters, and later encompassing surfing and other water sports.

Stability Characteristics of an Actively Valved Resonant Pulse Combustor

Abstract Resonant pulse combustors, one of the deflagration-based pressure gain combustion devices, can significantly increase thermal efficiency in gas turbine engines. This experimental study investigates the stability characteristics of a newly designed actively valved resonant pulse combustor, capable of sustained operation and meaningful stagnation pressure gain. The resonant pulse combustor was fired with liquid gasoline fuel while ion and pressure sensors captured the temporally resolved heat release and chamber pressure. First, experimental results were used to demonstrate the general operating principle of the combustor. Then, the stability characteristics of the device were investigated through frequency domain analysis of the ion probe and pressure signal traces. A low frequency oscillation (also observed in steady flames and passively valved resonant pulse combustors), was observed as the device was brought near to its blowout limit. Finally, an index was defined to predict the stability characteristics of the resonant pulse combustor by quantifying the competition between low frequency oscillations and combustion-driven resonance. Experimental results demonstrated the ability of this index to provide early prediction of a blowout event for this device.

Combined Additive and Laser-Induced Processing of Functional Structures for Monitoring under Deformation

This research introduces a readily available and non-chemical combinatorial production approach, known as the laser-induced writing process, to achieve laser-processed conductive graphene traces. The laser-induced graphene (LIG) structure and properties can be improved by adjusting the laser conditions and printing parameters. This method demonstrates the ability of laser-induced graphene (LIG) to overcome the electrothermal issues encountered in electronic devices. To additively process the PEI structures and the laser-induced surface, a high-precision laser nScrypt printer with different power, speed, and printing parameters was used. Raman spectroscopy and scanning electron microscopy analysis revealed similar results for laser-induced graphene morphology and structural chemistry. Significantly, the 3.2 W laser-induced graphene crystalline size (La; 159 nm) is higher than the higher power (4 W; 29 nm) formation due to the surface temperature and oxidation. Under four-point probe electrical property measurements, at a laser power of 3.8 W, the resistivity of the co-processed structure was three orders of magnitude larger. The LIG structure and property improvement are possible by varying the laser conditions and the printing parameters. The lowest gauge factor (GF) found was 17 at 0.5% strain, and the highest GF found was 141.36 at 5%.

The geochemistry of zinc and copper stable isotopes in marine hydrothermal brine pools: Perspectives from metalliferous sediments of the Atlantis II Deep, Red Sea

This study provides a zinc and copper stable isotope characterization (δ66Zn, δ68Zn, and δ65Cu) of metalliferous seafloor sediments from the Atlantis II Deep, a hydrothermally influenced brine basin in the Red Sea. Samples collected from box cores that capture the entire stratigraphy in the Deep have δ66Zn and δ65Cu values of −0.31 to 0.34 ‰ (0.02 ‰ median) and − 1.81 to 1.02 ‰ (−0.34 ‰ median) relative to the JMC-Lyon and NIST SRM 976 standards, respectively. These results suggest enrichments of light stable isotopes in sediments compared to the hydrothermal inputs to the basin, which likely overlap the mantle-like isotopic signatures of basalts beneath the Deep. Such shifts to lower δ66Zn and δ65Cu values are consistent with widespread metal sulfide deposition from the brines because sulfide anions preferentially consume the light stable isotopes of zinc and copper. However, this interpretation contrasts with observations in the open ocean, where the fractionation of zinc and copper stable isotopes is strongly influenced by biological utilization and organic matter. Previous studies proposed that metal deposition in the Atlantis II Deep is also driven by adsorption onto iron oxides/hydroxides and their weakly crystalline (Si-)Fe-OOH precursor phases within the brines. However, because this process should accumulate heavy zinc and copper stable isotopes, its influence on isotopic fractionation is likely limited. Controls by metal sulfide precipitation are also indicated by spatial covariations between δ66Zn and concentrations of zinc and copper, that is, δ66Zn values increase whereas metal contents decrease with distance away from hydrothermal venting. Comparable trends are lacking for copper isotopes, perhaps because of additional influence by redox processes or, compared to zinc, a much stronger influence by adsorption onto (Si-)Fe-OOH phases, particularly in areas distal to hydrothermal venting where reduced sulfur could be scarce. Collectively, our results from the Atlantis II Deep indicate that zinc and copper stable isotopes could provide information about base and precious metals deposits from similar paleoenvironments. Firstly, zinc and copper stable isotopes shed light on metal sourcing and accumulation processes. Secondly, mineral precipitation in hydrothermally influenced brine pools produces zinc stable isotope patterns that, at least theoretically, could be of interest in mineral exploration at sub-basin and deposit scales.