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This study aimed to develop a structural analysis method to replace and validate large-scale gas gun tests for evaluating the impact resistance of electronic equipment. By measuring projectile's deceleration through experiments and simulations, stress and strain during collisions were quantified. It was demonstrated that optimizing projectile and electronic equipment designs could enhance impact resistance. Simulation results indicated that changes in projectile velocity and head angle led to variations in maximum deceleration and penetration depth, with decreasing the head angle proving more effective in reducing maximum deceleration. Comparisons between experimental and simulation results showed good agreement, particularly in plots between maximum deceleration and target collision depth. As the head angle increased, there was a tendency for maximum deceleration to increase and target penetration depth to decrease. Comparing peak deceleration curves from gas gun tests and simulations revealed similar trends, indicating consistent results. This research provides important information for evaluating the impact resistance of electronic equipment and demonstrates that combining experiments with simulations can yield more reliable results.

The development of new advanced functionalities, miniaturization, and the aim of obtaining optimized performance in electronic devices significantly impacts their electromagnetic compatibility (EMC). As electronic components become more densely packed on a printed circuit board (PCB), unintended coupling between components can cause electromagnetic interference (EMI). These requirements result in design restrictions that make using a board level shield (BLS) essential in reducing intra-system EMI in PCB designs. This contribution focuses on studying and characterizing a BLS solution based on combining a noise suppression sheet (NSS) with an aluminum layer to reduce intra-system EMI coupling. This hybrid solution has the advantage of providing a shielding option that does not require any electronic redesign. It does not need a footprint or a ground connection as it can be affixed over the EMI source. The solution is expected to provide higher attenuation levels than using only an NSS by combining the absorbing properties of the magnetic material and the loss mechanism of the metal. In order to verify the effectiveness of the hybrid BLS proposed solution, the magnetic near-field emissions of an EMI source are analyzed in this study. The experimental measurements and simulated results demonstrate a significant increase (51.6 dB at 1 GHz) in the shielding effectiveness (SE) provided by the proposed solution compared to a conventional NSS. [ABSTRACT FROM AUTHOR]

Large deformation stress response characteristics of hydrocolloid mixture gel systems were investigated based on texture and rheological measurements. Agarose and xanthan mixtures at different ratios (1:0, 0.75:0.25, and 0.5:0.5) were chosen as the model systems. A decrease in failure stress from 2.65 to 1.82 MPa and an increase in failure strain from 0.08 to 0.13 with higher xanthan ratios were obtained based on the ring tensile test, indicating that xanthan molecules could improve the flexibility of the agarose network. The gels showed severe water loss by compression, particularly for the pure agarose gel (6.74%). Compared to the compression test, the gels presented low water loss after the ring tensile test (<1.3%) indicating that the ring tensile test could calculate the correct stress–strain relationship. Digital image correlation (DIC) and numerical simulation revealed that agarose-xanthan gel systems possess a deformation behavior with homogeneous strain distribution before failure. Elastic and viscous Lissajous–Bowditch curves from the large amplitude oscillatory shear (LAOS) measurement at different strains and frequencies elucidated that the agarose-xanthan gel was dominated by the agarose structure with a similar magnitude of elasticity at a low frequency. The large deformation approach from this study has great potential for elucidating and understanding the structure of food and biopolymer gels. [ABSTRACT FROM AUTHOR]

Temperature sensors have been widely applied in daily life and production, but little attention has been paid to the research on temperature sensors based on surface plasmon resonance (SPR) sensors. Therefore, an SPR temperature sensor with a triple structure of titanium dioxide (TiO2) film, gold (Au) film, and TiO2 nanorods is proposed in this article. By optimizing the thickness and structure of TiO2 film and nanorods and Au film, it is found that the sensitivity of the SPR temperature sensor can achieve 6038.53 nm/RIU and the detection temperature sensitivity is −2.40 nm/°C. According to the results, the sensitivity of the optimized sensor is 77.81% higher than that of the sensor with pure Au film, which is attributed to the TiO2(film)-Au-TiO2(nanorods) structure. Moreover, there is a good linear correlation (greater than 0.99) between temperature and resonance wavelength in the range from 0 °C to 60 °C, which can ensure the detection resolution. The high sensitivity, FOM, and detection resolution indicate that the proposed SPR sensor has a promising application in temperature monitoring. [ABSTRACT FROM AUTHOR]

• Thermal battery resilience under high-impact conditions was assessed to sustain continual power supply for electronic devices equipped with artillery projectiles. • Honeycomb buffering devices with different wall thicknesses were adopted to compare their energy-absorption capacities. • Large-scale gas-gun tests and finite element simulations comparing buffering devices revealed distinct deformation patterns influencing impact deceleration. • The thermal battery retrieved from the gas-gun test proved to have reliable impact resilience for the target performance. Modern warfare relies heavily on electronic equipment, necessitating reliable energy sources like thermal batteries. Assessing their impact resilience, a study employed honeycomb-structured Al plates as buffering devices in a large-scale gas gun simulating artillery fire. Comparison between peak curves from gas-gun tests and simulations with varying honeycomb wall thicknesses revealed unique patterns, attributed to the buffering device's deformation-restoration process. Different honeycomb wall thicknesses led to varying deformation behavior and impact deceleration, complicating effective energy absorption assessment. Stepped honeycomb wall designs aimed to balance compression, extending energy absorption and reducing deceleration peaks. Prototype honeycomb buffering devices showed improved energy absorption and reduced deceleration during gas-gun tests. Gas-gun tests highlighted complexities in energy absorption assessment, with designs proposing improved energy absorption and reduced deceleration. The actual gas-gun test launched a projectile equipped with a thermal battery and buffering device, resulting in slight casing deformation, while battery cells remained intact, exceeding the standard discharge time (1 h). [Display omitted] [ABSTRACT FROM AUTHOR]

Introduction The radiofrequency ablation (RFA) of liver cancer is a desirable treatment option, as it is minimally invasive. An accurate numerical simulation can greatly help physicians better plan their surgical protocols. Previously, the displacement current in the RFA process was considered negligible, and therefore RFA simulation was modeled as a direct current (DC) system instead of an alternating current (AC) system. Our study investigated the hypothesis that the displacement current in the RFA process should not always be considered negligible. Methods AC measurements of ex vivo bovine liver ablation were performed, and numerical simulations were also conducted to test the hypothesis that the relative permittivity would significantly decrease after the liver tissue reached a high temperature. Results The displacement current was observed to be a sizable fraction of the conduction current, especially before the onset of the first pause. The simulation results indicated that the relative permittivity is likely to decrease to several hundred or lower at elevated temperatures. Conclusions Our study results suggest that the DC model may be inadequate, especially before the first roll-off and that additional information could be available during RFA treatment by considering the AC nature of RFA, which could lead to improved numerical simulation. Additional measurements of tissue parameters are needed to reach the full potential of the AC model for further development of ablation control.

Large deformation stress response characteristics of hydrocolloid mixture gel systems were investigated based on texture and rheological measurements. Agarose and xanthan mixtures at different ratios (1:0, 0.75:0.25, and 0.5:0.5) were chosen as the model systems. A decrease in failure stress from 2.65 to 1.82 MPa and an increase in failure strain from 0.08 to 0.13 with higher xanthan ratios were obtained based on the ring tensile test, indicating that xanthan molecules could improve the flexibility of the agarose network. The gels showed severe water loss by compression, particularly for the pure agarose gel (6.74%). Compared to the compression test, the gels presented low water loss after the ring tensile test (

Thin AlN piezoelectric layers have been deposited on high resistivity Si and glass substrates by reactive RF magnetron sputtering, in order to manufacture one-port gigahertz operating surface acoustic wave (SAW)-type resonators to be used as temperature sensors. The growth morphology surface topography, crystallographic structure, and crystalline quality of the AlN layers have been analyzed. Advanced nanolithographic techniques have been used to manufacture structures having interdigitated transducers with fingers and finger interdigit spacing width in the range of 250–170 nm. High resonance frequency ensures the increase of the sensitivity, but also of its normalized value, the temperature coefficient of frequency (TCF). The resonance frequency shift versus temperature has been measured in the −267°C−+150°C temperature range, using a cryostat setup adapted for on wafer microwave measurements up to 50 GHz. The sensitivity and the TCF were determined in the 25 °C–150 °C temperature range. [ABSTRACT FROM AUTHOR]

Sensitivity is one of the most important parameters to put in the foreground in all sensing applications. Its increase is therefore an ongoing challenge, particularly for surface acoustic wave (SAW) sensors. Herein, finite element method (FEM) simulation using COMSOL Multiphysics software is first used to simulate the physical and electrical properties of SAW delay line. Results indicate that 2D configuration permits to accurately obtain all pertinent parameters, as in 3D simulation, with very substantial time saving. A good agreement between calculation and experiment, in terms of transfer functions (S21 spectra), was also shown to evaluate the dependence of the SAW sensors sensitivity on the operating frequency; 2D simulations have been conducted on 104 MHz and 208 MHz delay lines, coated with a polyisobutylene (PIB) as sensitive layer to dichloromethane (DCM). A fourfold increase in sensitivity was obtained by doubling frequency. Both sensors were then realized and tested as chem-sensors to detect zinc ions in liquid media. 9-{[4-({[4-(9anthrylmethoxy)phenyl]sulfanyl} methyl)]methyl] anthracene (TDP-AN) was selected as the sensing layer. Results show a comparable response curves for both designed sensors, in terms of limit of detection and dissociation constants Kd values. On the other hand, experimental sensitivity values were of the order of [7.0 ± 2.8] × 108 [°/M] and [16.0 ± 7.6] × 108 [°/M] for 104 MHz and 208 MHz sensors, respectively, confirming that the sensitivity increases with frequency.

Controlling the heat transport and thermal conductivity through a material is of prime importance for thermoelectric applications. Phononic crystals, which are a nanostructured array of specially designed pores, can suppress heat transportation owing to the phonon wave interference, resulting in bandgap formation in their band structure. To control heat phonon propagation in thermoelectric devices, phononic crystals with a bandgap in the THz regime are desirable. In this study, we carried out simulation on snowflake shaped phononic crystal and obtained several phononic bandgaps in the THz regime, with the highest being at ≈2 THz. The phononic bandgap position and the width of the bandgap were found to be tunable by varying the neck-length of the snowflake structure. A unique bandgap map computed by varying the neck-length continuously provides enormous amounts of information as to the size and position of the phononic bandgap for various pore dimensions. We have also carried out transmission spectrum analysis and found good agreement with the band structure calculations. The pressure map visualized at various frequencies validates the effectiveness of snowflake shaped nano-pores in suppressing the phonons partially or completely, depending on the transmission probabilities.

The first European superconducting winding pack (WP) and the first set of coil cases [toroidal field coil cases (TFCC)] for ITER are going to be delivered in 2017. The TFCC are steel structures that provide structural integrity to the WP, contribute to neutron shielding capacity, provide support to operating forces, and offer interface connections with the rest of the ITER machine. The TFCC assembly is formed by four main parts: two sectors with U-shaped section and two closure plates, which, after being welded together, enclose the WP. Each TFCC weights about 150 t and presents a wall thickness from 60 to 120 mm. The presence of distortions when welding such thick structures is particularly problematic in these components, which require tight tolerances and include several interfaces with other parts of the machine. In order to compensate the distortions, extra material is present in the critical areas to allow postwelding machining. The amount of extra material has to be optimized to reduce machining time and therefore the cost of the manufacturing. Thus, the evaluation of the welding-caused distortions is essential in order to confirm the extra-material strategy. In this scenario, an experimental and simulation campaign has been set up to predict the deformation of the TFCC during welding. First, welding coupons were welded in representative configurations. Then, these data were used to build a preliminary finite element method (FEM) model tool, using ANSYS software, which was then benchmarked against a "blind test" coupon and three TFCC-like mock-ups of 1-m length. Finally, a full FEM model was constructed using the previous outputs and is currently under assessment to predict the deformation of the TFCC during the welding process. This paper presents the numerical and experimental activities carried out so far, being EnginSoft S.p.A. the developer of FEM models, SIMIC S.p.A. the responsible of welding processes and data acquisition, and Fusion for Energy the contractual and technical supervisor. [ABSTRACT FROM AUTHOR]

Frequency trimming based on mass and stiffness modification is an important post-fabrication process for micro-shell resonators (MSRs). However, the trimming effects on the quality factor are seldom studied, although they may have great influence on the performance of the resonator. This paper presents a study on the quality factor (Q-factor) variation of trimmed micro-shell resonators (MSR). Thermoelastic damping (QTED) and anchor loss (Qanchor) are found to be the dominant energy loss mechanisms resulting in the reduction of the overall Q-factor, according to finite element method (FEM). The effects of different trimming methods on QTED and Qanchor are studied here, respectively. It is found that trimming grooves ablated in the rim of the resonator can cause a ~1−10% reduction of QTED, and the length of trimming groove is positively related to the reduction of QTED. The reduction of QTED caused by the mass adding process is mainly related to the thermal expansion coefficient and density of the additive and contact area between the resonator and additive masses. Besides, the first and second harmonic errors caused by asymmetrical trimming can cause a 10−90% reduction of Qanchor. Finally, trimming experiments were conducted on different resonators and the results were compared with FEM simulation. The work presented in this paper could help to optimize the trimming process of MSRs.

In this paper, a novel technique is proposed to improve the wireless power transfer efficiency for downhole logging environment. The method applies a soft ferrite layer on the oil pipe so that the magnetic coupling between the transmitter and the receiver is greatly enhanced. Power transfer efficiency is calculated via electromagnetic simulation using the finite element method. A prototype was built to demonstrate the effectiveness of the technique. [ABSTRACT FROM AUTHOR]

This study reports the controllable surface roughening of Au-Ag alloy nanoplates via the galvanic replacement reaction between single-crystalline triangular Ag nanoplates and HAuCl in an aqueous medium. With a combination of experimental evidence and finite element method (FEM) simulations, improved electromagnetic field (E-field) enhancement around the surface-roughened Au-Ag nanoplates and tunable light absorption in the near-infrared (NIR) region (~800-1,400 nm) are achieved by the synergistic effects of the localized surface plasmon resonance (LSPR) from the maintained triangular shape, the controllable Au-Ag alloy composition, and the increased surface roughness. The NIR light extinction enables an active photothermal effect as well as a high photothermal conversion efficiency (78.5%). The well-maintained triangular shape, surface-roughened evolutions of both micro- and nanostructures, and tunable NIR surface plasmon resonance effect enable potential applications of the Au-Ag alloy nanoplates in surface-enhanced Raman spectroscopic detection of biomolecules through 785-nm laser excitation. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

It is essential to characterize the in-plane thermal conductivity of polymer materials accurately in many applications. Although there exist a few appropriate steady and transient characterizing techniques to accomplish the task, the methods often require complicated micro-fabrication, calibration or additional property determination procedures (e.g. , some transient approaches only yield in-plane thermal diffusivity. Thus the volumetric heat capacity C V needs to be measured independently in order to calculate the thermal conductivity.). In this work, we have employed a membrane-based modified Ångström (MMA) method to directly measure the in-plane thermal conductivity of several micrometer thick polymer materials. The suspended polymer membranes are patterned with double metal strips made by simple shadow mask deposition. The metal strips are used to create periodical Joule heating and to perform temperature sensing. The measurement of the in-plane thermal conductivity is carried out without requiring the knowledge of the C V value. The accuracy of the approach has been verified by numerical calculations. The measured thermal conductivities for poly(tetrafluoroethylene) (PTFE) and polyimide (PI) samples were found to be comparable with available literature values. Since the in-plane thermal diffusivity of the membrane can be obtained simultaneously, its reliability was also evaluated. Moreover, the possibilities of applying the MMA method to other materials (e.g. , high thermal conductivity membrane) have been discussed. This study suggests that the MMA method coupled with shadow-masking technique may offer a straightforward and reliable way of measuring the in-plane thermal conductivity of several micrometer thick free-standing membranes. [ABSTRACT FROM AUTHOR]

Sensitivity is one of the most important parameters to put in the foreground in all sensing applications. Its increase is therefore an ongoing challenge, particularly for surface acoustic wave (SAW) sensors. Herein, finite element method (FEM) simulation using COMSOL Multiphysics software is first used to simulate the physical and electrical properties of SAW delay line. Results indicate that 2D configuration permits to accurately obtain all pertinent parameters, as in 3D simulation, with very substantial time saving. A good agreement between calculation and experiment, in terms of transfer functions (S21 spectra), was also shown to evaluate the dependence of the SAW sensors sensitivity on the operating frequency; 2D simulations have been conducted on 104 MHz and 208 MHz delay lines, coated with a polyisobutylene (PIB) as sensitive layer to dichloromethane (DCM). A fourfold increase in sensitivity was obtained by doubling frequency. Both sensors were then realized and tested as chem-sensors to detect zinc ions in liquid media. 9-{[4-({[4-(9anthrylmethoxy)phenyl]sulfanyl} methyl)]methyl] anthracene (TDP-AN) was selected as the sensing layer. Results show a comparable response curves for both designed sensors, in terms of limit of detection and dissociation constants Kd values. On the other hand, experimental sensitivity values were of the order of [7.0 ± 2.8] × 108 [°/M] and [16.0 ± 7.6] × 108 [°/M] for 104 MHz and 208 MHz sensors, respectively, confirming that the sensitivity increases with frequency. [ABSTRACT FROM AUTHOR]

Controlling the heat transport and thermal conductivity through a material is of prime importance for thermoelectric applications. Phononic crystals, which are a nanostructured array of specially designed pores, can suppress heat transportation owing to the phonon wave interference, resulting in bandgap formation in their band structure. To control heat phonon propagation in thermoelectric devices, phononic crystals with a bandgap in the THz regime are desirable. In this study, we carried out simulation on snowflake shaped phononic crystal and obtained several phononic bandgaps in the THz regime, with the highest being at ≈2 THz. The phononic bandgap position and the width of the bandgap were found to be tunable by varying the neck-length of the snowflake structure. A unique bandgap map computed by varying the neck-length continuously provides enormous amounts of information as to the size and position of the phononic bandgap for various pore dimensions. We have also carried out transmission spectrum analysis and found good agreement with the band structure calculations. The pressure map visualized at various frequencies validates the effectiveness of snowflake shaped nano-pores in suppressing the phonons partially or completely, depending on the transmission probabilities. [ABSTRACT FROM AUTHOR]

Introduction: The radiofrequency ablation (RFA) of liver cancer is a desirable treatment option, as it is minimally invasive. An accurate numerical simulation can greatly help physicians better plan their surgical protocols. Previously, the displacement current in the RFA process was considered negligible, and therefore RFA simulation was modeled as a direct current (DC) system instead of an alternating current (AC) system. Our study investigated the hypothesis that the displacement current in the RFA process should not always be considered negligible., Methods: AC measurements of ex vivo bovine liver ablation were performed, and numerical simulations were also conducted to test the hypothesis that the relative permittivity would significantly decrease after the liver tissue reached a high temperature., Results: The displacement current was observed to be a sizable fraction of the conduction current, especially before the onset of the first pause. The simulation results indicated that the relative permittivity is likely to decrease to several hundred or lower at elevated temperatures., Conclusions: Our study results suggest that the DC model may be inadequate, especially before the first roll-off and that additional information could be available during RFA treatment by considering the AC nature of RFA, which could lead to improved numerical simulation. Additional measurements of tissue parameters are needed to reach the full potential of the AC model for further development of ablation control.

Frequency trimming based on mass and stiffness modification is an important post-fabrication process for micro-shell resonators (MSRs). However, the trimming effects on the quality factor are seldom studied, although they may have great influence on the performance of the resonator. This paper presents a study on the quality factor (Q-factor) variation of trimmed micro-shell resonators (MSR). Thermoelastic damping ( Q TED ) and anchor loss ( Q anchor ) are found to be the dominant energy loss mechanisms resulting in the reduction of the overall Q-factor, according to finite element method (FEM). The effects of different trimming methods on Q TED and Q anchor are studied here, respectively. It is found that trimming grooves ablated in the rim of the resonator can cause a ~1-10% reduction of Q TED , and the length of trimming groove is positively related to the reduction of Q TED . The reduction of Q TED caused by the mass adding process is mainly related to the thermal expansion coefficient and density of the additive and contact area between the resonator and additive masses. Besides, the first and second harmonic errors caused by asymmetrical trimming can cause a 10-90% reduction of Q anchor . Finally, trimming experiments were conducted on different resonators and the results were compared with FEM simulation. The work presented in this paper could help to optimize the trimming process of MSRs., Competing Interests: The authors declare no conflict of interest.