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The accuracy of the machining process is highly dependent on how well a workpiece is constrained in a fixture. A well-constrained workpiece has high stiffness and shows minimum deformation under the application of load. Workpiece can be constrained by the proper positioning of fixture elements. This research introduces a finite element-based numerical methodology to automatically select optimum number and position of clamps in the sheet metal, necessary for good quality of manufacturing process. The objective function is to minimize the total deformation normal to the plane of sheet metal while keeping maximum deformation of individual nodes upto 2 mm. The N-3-2-1 fixturing principle is used to place clamps on primary plane of the workpiece. The proposed method consists of two stages; in first stage, the initial number of clamps are determined. In second stage, initial number of clamps and their positions are optimized using genetic algorithm. The proposed method implemented on the case studies successfully reduced the total deformation with optimized number of clamps. The maximum deformation in individual nodes was kept upto 2 mm. An experimental setup was developed to verify the numerical results. The numerical and experimental results fully justify the proposed method. [ABSTRACT FROM AUTHOR]

Purpose: To examine the effect of match schedule on self-reported wellness and sleep in rugby union referees during the 2019 Rugby World Cup. Methods: Following an observational design, 18 international-level male referees participating in the 2019 Rugby World Cup completed a daily questionnaire to quantify wellness status (sleep quality, mood, stress, fatigue, muscle soreness, and total wellness) and sleep characteristics (bedtime, wake-up time, and time in bed) from the previous night across the tournament. Linear mixed models and effect sizes (Hedges gav) assessed differences in wellness and sleep characteristics between prematch and postmatch days surrounding single-game and 2-game congested match schedules (prematch1, postmatch1, prematch2, and postmatch2 days). Results: During regular schedules, all self-reported wellness variables except stress were reduced (gav = 0.33–1.05, mean difference −0.32 to −1.21 arbitrary units [AU]) and referees went to bed later (1.08, 1:07 h:min) and spent less time in bed (−0.78, 00:55 h:min) postmatch compared with prematch days. During congested schedules, only wellness variables differed across days, with total wellness reduced on postmatch1 (−0.88, −3.56 AU) and postmatch2 (−0.67, −2.70 AU) days, as well as mood (−1.01, −0.56 AU) and fatigue (−0.90, −1.11 AU) reduced on postmatch1 days compared with prematch days. Conclusion: Referees were susceptible to acute reductions in wellness on days following matches regardless of schedule. However, only single-game regular match schedules negatively impacted the sleep characteristics of referees. Targeted strategies to maximize wellness status and sleep opportunities in referees considering the match schedule faced should be explored during future Rugby World Cup competitions. [ABSTRACT FROM AUTHOR]

Cranial defects are often caused by trauma, diseases or malignancy. To repair such defects, skull reconstruction or cranial implants are required for protecting intracranial structures and normalizing cerebral hemodynamics. To relieve Intracranial Pressure (ICP) surgeons restore cranial defects using the preserved bone of a patient. In case of non-availability of natural bone cranial implants are fabricated using biocompatible materials including Titanium Alloys (Ti-6Al-4V) and polyether-ether-ketone (PEEK). Patient-specific implants (PSI) manufactured using 3D printing, 3D imaging technologies and 3D modeling software, are preferred over conventional manufacturing methods. During cranial fixation bone fragments, grafts and bone flaps are fixed to the cranium to offer stable closure in surgery. Effective attachment of an implant to a defective skull is influenced by the joints and fixture arrangements at the interface. These fixtures can have various designs, materials and joining procedures. PEEK behaves similarly to bone during deformation, which means it is receptive to titanium fixations and supports soft tissue adhesion due to its inert nature. This study considers PEEK as an implant material for reconstructing a bone-defected skull with Ti-6Al-4V fixtures attached at the skull-implant interface. This work compares Ti-6Al-4V fixture shapes (Linear, Square and Burrhole) with different orientation angles and topologies ('+' and 'X') attached to PEEK cranial implants of variable thicknesses (1–7 mm). Using Finite Element Method (FEM)/Finite Element Analysis (FEA), von Mises stress analysis was analyzed to identify the implant thicknesses that would bear an external load of 1780 N and ICP of 15 mmHg without failure. With a yielding limit of 100 MPa for PEEK, all proposed design arrangements for the fixture plates in the skull-implant assembly were well within these limits exhibiting a maximum von Mises stress of 51.985 MPa for the least implant thickness of 1 mm and weight 12.90 g. Considering all the designs, a Linear Fixture shape with 45° angular orientations placed in 'X' topology exhibited least stress of 18.477 MPa and was therefore proposed as the most optimized design for the skull-implant fixture assembly. Selection of an optimized design arrangement is also dependent upon other clinical factors, such as number of screws used, the Additive Manufacturing (AM) technique for fabricating/cutting of precise slots within the implant. The skull and flexibility of the fixture plates are also considered in relation to the required operating theatre time and skills of the surgical team. [ABSTRACT FROM AUTHOR]

People with special needs and people of determination are an integral part of society, that henceThe research discusses a new vision in dealing disabled people with buildings, so that they can be integrated into society and contribute to life in addition and production. This can be achieved by designing buildings, roads and even friendly cities by providing some conditions, updating and developing them according to modern design techniques. The research exposed to achieve and meet these needs within the service parts of the building, the technical devices and installations. As the research reviews its problem represented in neglecting those technical installations and the necessity of updating them according to modern and developed technology, then the importance of the research and its assumptions, limits and its theoretical methodology. The research also discusses the requirements proposed to work with and their application in the control tools of the building operation through the empty spaces, electrical outlets, taps, buttons, information signals, lighting panels and the uses of colours, as well as some technical installations to be developed in service architectural spaces in the building in public and private toilets inside the building in terms of location, toilets cabins, signs, doors, interior fittings, requirements for handles, lighting, and interior finishes. As well as the requirements that must be met by using modern technology in sanitary devices, such as a toilet device, sinks, urinals, bathtubs, shower rooms, cabins (showers), toilet accessories, and in changing rooms in toilets, that is explained with a proposal for the required sizes and figures shown, then making research recommendations and references.

Fixture layout is a complex task that significantly impacts manufacturing costs and requires the expertise of well-trained engineers. While most research approaches to automating the fixture layout process use optimization or rule-based frameworks, this paper presents a novel approach using supervised learning. The proposed framework replicates the 3-2-1 locating principle to layout fixtures for sheet metal designs. This principle ensures the correct fixing of an object by restricting its degrees of freedom. One main novelty of the proposed framework is the use of topographic maps generated from sheet metal design data as input for a convolutional neural network (CNN). These maps are created by projecting the geometry onto a plane and converting the Z coordinate into gray-scale pixel values. The framework is also novel in its ability to reuse knowledge about fixturing to lay out new workpieces and in its integration with a CAD environment as an add-in. The results of the hyperparameter-tuned CNN for regression show high accuracy and fast convergence, demonstrating the usability of the model for industrial applications. The framework was first tested using automotive b-pillar designs and was found to have high accuracy (≈ 100%) in classifying these designs. The proposed framework offers a promising approach for automating the complex task of fixture layout in sheet metal design. [ABSTRACT FROM AUTHOR]

Although nano and macro manufacturing encompass two different scales of machining, investigating both is essential for understanding machining distortions and deformations. In both macro and nano fabrication, the fixture is the primary means of securing the workpiece in place while performing the manufacturing operations. Understanding the fixture design is a critical aspect relating the two different scales of manufacturing. This paper describes a method involving atomistic simulation for understanding machining distortions for the macro scale by investigation of nano machining and work holding devices. This research aims to help bridge the knowledge gap in manufacturing of macro and nano scale applications. The simulations performed showed that the fixture influences the machining distortions and the critical stress concentrations on the workpiece.

Although nano and macro manufacturing encompass two different scales of machining, investigating both is essential for understanding machining distortions and deformations. In both macro and nano fabrication, the fixture is the primary means of securing the workpiece in place while performing the manufacturing operations. Understanding the fixture design is a critical aspect relating the two different scales of manufacturing. This paper describes a method involving atomistic simulation for understanding machining distortions for the macro scale by investigation of nano machining and work holding devices. This research aims to help bridge the knowledge gap in manufacturing of macro and nano scale applications. The simulations performed showed that the fixture influences the machining distortions and the critical stress concentrations on the workpiece.

Programmable logic controllers (PLCs) are used to control devices throughout the power system since they have fast control capabilities and can utilize multiple types of communication interfaces. Therefore, studying and mitigating their vulnerabilities to electromagnetic pulse is important for the reliability of PLC operations. In this article, an effective impedance measurement scheme is proposed and demonstrated for three PLCs to estimate their susceptibility to an electromagnetic pulse. The equivalent nonuniform transmission line model is established to eliminate the impact of the fixture in the de-embedding process. Then, different parameters of the impedance measurement setup are explored. Based on the measured impedance, the equivalent circuit is established to calculate the response of the device when subjected to the electromagnetic pulse. The voltage and current responses of different interfaces are compared utilizing the developed pulsed current injection (CI) method. Finally, the impedance measurement scheme is verified through testing using three measuring instruments. And the CI simulation experiments reveal the characteristics and susceptibilities of different PLCs interfaces, indicating that some protection measures are required for the reliable operation of the PLC. [ABSTRACT FROM AUTHOR]

A principal part of the Comprehensive Research Facility for Fusion Technology (CRAFT) is the toroidal field (TF) coil project, which aims at fabricating a prototype TF coil for China Fusion Engineering Test Reactor (CFETR). The TF coil is composed of 3-D-shaped subwinding packs (sub-WPs) enclosed in a stainless coil case, and the conductor core of medium and high field sub-WPs is Nb3Sn, following the “Winding & Reaction” manufacturing process. After heat treatment of the conductor, turn insulation will be automatically wrapped. Strictly restricted by the brittleness of the heat-treated Nb3Sn, the strain must be controlled during the wrapping process. Presented in this article is a description of the CRAFT TF coil and its turn insulation structure, followed by descriptions of the structural design of the wrapping unit and mathematical models about wrapping control of the wrapping machine. Turn insulation wrapping trials are performed with one-fourth part of the wrapping unit, and tapes with a fixed width and a uniform steel tube are used as specimens, verifying the correctness of the structure and models. The one-fourth part of the wrapping unit has been fabricated in March 2022 and it is foreseen that the fabrication will be finished in June 2022. [ABSTRACT FROM AUTHOR]

This paper examines the law of fixtures and chattels which governs the circumstances in which items of personal property that are attached to land become part of that land. Whether a chattel has become a fixture is crucial in a range of contexts including when land is sold or mortgaged. However, the law of fixtures has long garnered a reputation for complexity and obscurity; a position that endures today. Through examination of historical accounts and decided case law, this paper explores the reasons for this reputation; identifies the central deficiencies and defects inherent in the law and argues that the existing approach is anachronistic, inconsistent and incoherent. Building on this, the paper concludes by proposing a new framework for rationalisation and reform which would bring long-overdue certainty and clarity to the law in this area. [ABSTRACT FROM AUTHOR]

Designing and installing jigs and fixtures for new products are very costly tasks. In order to rapidly respond to frequent product changes in a manufacturing system, we developed a transformable pin array fixture system including reconfiguration planning software that finds the optimal position for mounting an assembly part and automatically generates a pin height control code. We first classified main fixturing quality factors such as type of contact, distance between a pin and a joining point, and part shape. We then formulate the part positioning problem as an alignment problem between the joining point set and the pin point set in the xy plane in consideration of the fixturing quality factors. A car door trim assembly module was used to verify the proposed method. Finite-element analysis results showed that in a car door trim assembly process such as ultrasonic welding and screwing, relocating an assembly part at the optimal position reduces its deformation. Note to Practitioners—Jigs and fixture systems are the fundamental manufacturing elements that are used for ensuring assembly quality. Traditionally, manufacturers have produced a small variety of products in massive quantities using dedicated jig and fixture systems. However, these dedicated workholding systems do not fit for the Today’s rapidly changing market. In order to enhance the reconfigurability of these systems, we propose a transformable pin array-based part fixturing system including part position optimization. Due to the system complexity, the assembly quality can be lower using the transformable fixtures than the conventional fixtures. Therefore, it is further necessary to develop a cost-effective reconfigurable fixture while preserving the assembly quality for the better chance of its industrial implementation. [ABSTRACT FROM AUTHOR]

In the mass production of electronic products, in-circuit-test (ICT) and printed circuit board assembly (PCBA) quality tests are performed. ICT measures resistance values and capacitance, but not only does it require the use of a fixture that is expensive and requires frequent replacement but also the fixture’s needles may cause PCBA defects. To overcome these limitations, various studies tried to replace ICT using visual inspection methods; however, visual inspection methods cannot be applied to chip resistors and chip capacitors that do not have externally visible characteristics. In this article, we propose a contactless inspection method that can detect PCBA defects without the use of the fixture and ICT by using the comparison of thermal images and deep learning (DL) analysis. We review the existing contactless inspection methods and compare them with our proposed thermal image analysis method. We analyzed thermal images by applying a structural similarity index map as a rule-based object detection method, and we used convolutional neural networks (CNNs), regions with CNN features, and an autoencoder as DL analysis methods. As a result, we achieved highly accurate defective component detection and location in real time. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to devise customized fixtures for the evaluation of three-point bending strength (TPBS) of resin-based dental composites (RBCs). Materials and Methods: A cube-shaped jig made out of wood with dimensions of 105×105×101 mm was prepared in this study. A 20-mm-diameter hole was made in the center of the wooden jig. In addition, a stainless steel probe with 175mm length, 3mm thickness, and 2 mm width was fabricated and then fitted in the upper gripping crosshead of the universal testing machine. Subsequently, bar-shaped specimens of two commercial RBCs, namely Filtek Z350 XT Supreme Ultra Universal (Z350) and Premium Nano-Hybrid Composite (PN) were placed over the center of the jig hole and subjected to TPBS test in accordance with ISO 4049 standards protocol. Results: The mean TPBS values of Z350 and PN RBCs were 82 and 86 MPa, respectively. Moreover, the standard deviation values for both mean TPBS values were low indicating the homogeneity of the findings and associated reliability of the employed fixtures. Conclusion: The fixtures for the TPBS test of RBCs were successfully designed and developed which would likely facilitate the researchers with a mechanical characterization of dental materials. A machine used for the testing of large industrial materials other than small dimensional dental materials can now be used to test TPBS of RBCs according to ISO 4049 with the help of the invented economical fixtures. This will enhance the quality of teaching and learning of materials science in developing countries.

With the rapid development of vehicle information systems, liquid crystal displays (LCDs) have been widely used to enhance information experience. A linear vibration motor is usually placed behind the LCD to provide sufficient haptic feedback. A linear vibration motor with a large permanent magnet causes massive flux leakage around the display. As a result, it may cause unpredictable harm to people with implanted medical devices. Therefore, in this article, a novel magnetic circuit design of a slim-width type linear vibration motor is introduced to reduce the static magnetic flux leakage. The haptic performance of the slim-width type linear vibration motor was analyzed using the electromagnetic–mechanical coupling method. Three types of experimental results were obtained to verify the analysis results. In conclusion, compared with the prototype motor, the slim-width type linear vibration motor proposed in this article exhibits significant flux leakage reduction of 94.01% and 96.34% at the measuring positions. Furthermore, the slim-width type linear vibration motor exhibits an acceleration similar to that of the prototype motor. [ABSTRACT FROM AUTHOR]

Fixtures are an important element of the manufacturing system, as they ensure productive and accurate machining of differently shaped workpieces. Regarding the fixture design or the layout of fixture elements, a high static and dynamic stiffness of fixtures is therefore required to ensure the defined position and orientation of workpieces under process loads, e.g. cutting forces. Nowadays, with the increase in computing performance and the development of new algorithms, machine learning (ML) offers an appropriate possibility to use regression methods for creating realistic, rapid and reliable equivalent ML models instead of simulations based on the finite element method (FEM). This research work introduces a novel method that allows an optimization of clamping concepts and fixture design by means of ML, in order to reduce manufacturing errors and to obtain an increased stiffness of fixtures and machining accuracy. This paper describes the preparation of a dataset for training ML models, the systematic selection of the most promising regression algorithm based on relevant criteria, the implementation of the chosen algorithm Extreme Gradient Boosting (XGBoost) and other comparable algorithms, the analysis of their regression results, and the validation of the optimization for a selected clamping concept. [ABSTRACT FROM AUTHOR]

A wideband circularly polarized (CP) endfire planar magneto-electric dipole antenna based on substrate integrated waveguide (SIW) is proposed for millimeter-wave (mm-wave) applications. The antenna mainly consists of an open-ended rectangular SIW radiating like a magnetic dipole, a parallel electric dipole, and a double-sided parallel-strip line which connects the two dipoles and provides 90° phase difference between them to generate CP radiation. To increase the axial ratio (AR) bandwidth, a pair of triangular slots are etched at the end of the upper and lower broad walls of the SIW, and moreover, a specific bowtie-shaped electric dipole is used instead of the traditional linear one. It has been shown that both the slots and the bowtie-shaped electric dipole can regulate or tune the magnitude of the radiation field of the electric dipole, making it tend to balance with radiation field generated by the magnetic dipole, and hence, leading to a good CP performance. The antenna has a single-layer planar structure, and it shows a −10 dB impedance bandwidth of over 50%, a 3 dB AR bandwidth of 36.6%, and a peak gain of 9.3 dBic. [ABSTRACT FROM AUTHOR]

This work presents a novel miniaturized waveguide cell with water filling for passive intermodulation (PIM) localization on planar circuits. The planar circuit as printed circuit board (PCB) is excited in a small waveguide, while its PIM product is detected simultaneously. The waveguide width is minimized by water filling (high permittivity dielectric), and the localization resolution is enhanced. During test, the PCB only needs move through the waveguide twice, once along its $X$ -direction and once along its $Y$ -direction. By crossing the peak PIM distribution line along two directions together, the regions on PCB have PIM responses that can be decided. The proposed method is intended for the planer PCB and other normal PCB with surface mount components. [ABSTRACT FROM AUTHOR]

Experimental characterization of high-strength fine wires often arises challenges greater than expected due to the difficulties encountered gripping the wire to the fixtures. To avoid premature breakage within the fixtures, capstan grips are widely utilized, but slippage might occur unless the wire is folded many times around the capstan. Further, estimating the actual elongation of the gauge section might be an issue since wires do not deform in the gauge section only but also within the folded length. This work proposes a simple clamping approach relying on sacrificial tabs made of soft and ductile material allowing to utilize classic wedge-shaped steel jaws to characterize high-strength fine wires without encountering any slippage or break within the gripping region. The suggested tabbing strategy further allows referring to the crosshead motion to evaluate the overall strain in the wire as its deformation concentrates only over the gauge length, hence excluding the use of an extensometer. This is particularly needed in the case of testing in a climatic chamber. On top of the experimental evidence, the proposed tabbing methodology is studied through analytical solutions and finite element analyses, which result in a generalized design tool that can be utilized to choose the best material and dimensions of the sacrificial tabs to correctly test wires other than the ones considered in this work.

Tektronix, Inc., in collaboration with Anritsu, has introduced a new PCI EXPRESS® 5.0 transceiver (Base and CEM) and reference clock solution, claiming to be the first company to offer early CEM fixtures for pre-compliance testing. The collaboration between Tektronix and Anritsu enables industry-leading receiver verification, complementing a world-class transmitter and reference clock test suite. [ABSTRACT FROM AUTHOR]

Aiming at the traditional design methods, there were some prominent problems, such as low design efficiency, long product development cycle and high work intensity of engineering designers, with the study of the design characteristics of turbine blade fixture, a Top-Down design method based on rule and case hybrid reasoning was proposed. Firstly, the serialized and parameterized parts of the blade fixture were established, the assembly constraints and parameter associations of each part were carried out, and the fixture instance library was constructed. Based on the top-down design idea and the fixture instance coding system, a similarity calculation method for the weighted average of the primary factors was proposed, and similar fixture instances were retrieved and reused. Finally, according to the needs of blades, strength and stiffness, etc., limited manual intervention was carried out on the clamps, and the new clamps that meet the functional requirements of U103 clamps were driven from the top down to generate. The results show that the Top-Down design of turbine blade fixture based on hybrid reasoning significantly improves the design efficiency, simplifies the complexity of the work. [ABSTRACT FROM AUTHOR]

High-end commercially available CAD/PLM systems support virtual simulation of assembly procedures using digital avatars. An advanced solution involves real people in virtual manufacturing environment. This work presents development of a Virtual Reality environment based on an open game engine. This is developed in order to test assembly plans executed on a purpose-designed workstation including specially designed fixtures and all necessary tools for manual assembly of a large centrifugal pump. The system allows the engineer to evaluate and suitably modify the fixtures and overall workstation layout as well as perform preliminary checks on productivity and ergonomics of product assembly before any equipment is built or commissioned. Due to its open nature such a system can further evolve in complexity. [ABSTRACT FROM AUTHOR]

Fixture design is one of the main factors which affect the final product quality. Proper design of fixture plays an important role in ensuring the required tolerance of the product. Proper placement of locators is one of the prominent factors in fixture design. Locators are elastic: they deform under clamping and machining forces causing rigid body displacement of the workpiece which in turn affects the part quality. In this article, a 3-2-1 type of fixturing system having elastic locators around a considerably rigid rectangular workpiece is considered. A genetic algorithm is proposed, which uses a fitness function that evaluates the positioning error of the workpiece under external forces and torque. Among several variables, 12 variables, which define the placement of locators, are chosen to be optimized while minimizing the positioning error of the workpiece at the point of action of machining force. The proposed algorithm optimizes the 12 interlinked variables, within the specified region, for machining force and torque at a single point. However, when the cutting tool moves to any other point on the workpiece, it is observed that either the workpiece loses its contact with any one of the locators or the positioning error increases by a large value. To overcome this issue, the proposed algorithm is further modified for placement optimization to cater for multi-point machining, and the isostatism of the workpiece is ensured by checking the magnitude and direction of displacement (of what?) at each point of workpiece-locator contact. Finally, the original and modified GA algorithms are explained through a case study where the single point optimized placement shows loss of contact when machining force is applied at other points. The placement optimized from the modified algorithm shows that the isostatism of the workpiece remains intact while all four positioning errors are converged towards the same value. The results obtained from the proposed and modified algorithm are verified using ANSYS simulation. [ABSTRACT FROM AUTHOR]

Press-pack insulated gate bipolar transistors (PP-IGBTs) are commonly connected in series and stacked together with heatsinks using an exterior clamping fixture in order to achieve high-voltage dc-link levels. A suitable contact area between the clamping fixture and the device is essential to ensuring optimal PP-IGBT thermomechanical performance, especially for the first and last devices in a stack. In this study, the effects of the clamping area on collector deformation, temperature, and stress distributions are investigated by means of the finite-element method (FEM). Moreover, this article analyzes the influence of heatsink thickness to maximize the stress evenness of the terminal PP-IGBT and reduce the overall length of the stack system. The results indicate that the collector lid is prone to warpage due to thermal expansion, which results in a decrease in the effective contact area between component layers. As the contact resistance increases, the chips accumulate considerable heat. Increasing the clamping area at this point can adequately compensate for the warp deformation and can also improve the stress uniformity of the chips. Finally, an experiment making use of stress-sensitive film has been carried out to verify the developed FEM models. [ABSTRACT FROM AUTHOR]

The accelerating commercialization of wide bandgap technology has led to increased demand for accurate characterization of parasitic impedances within packaging structures such as multichip power modules. However, the accuracy of known methods is not sufficient to characterize high-performance modules which have extremely low parasitics, with impedance values near the measurement floor of common instrumentation. To address this characterization gap, this article introduces a custom measurement methodology that utilizes a general-purpose instrument and fixture but reduces systematic and stochastic error to an acceptable level through an emphasis on rigorous calibration and measurement consistency. Additionally, fixture compensation is performed via post-processing in MATLAB to improve measurement fidelity via statistical techniques. The proposed methodology is validated with a series of known test samples in the impedance range of interest. Finally, the methodology is used to perform parasitic characterization of a high-performance power module with commutation loop inductance previously reported to be less than 1.6 nH. [ABSTRACT FROM AUTHOR]

In this study, a wideband rounded-shield calibration fixture or jig used to calibrate in-band injection probe is implemented based on 3D electromagnetic modelling in CST Microwave Studio; the Electromagnetic (EM) model is validated and then used in studying the effect of the jig layout parameters on its bandwidth. The impact of a rounded instead of the typical flat shield is studied too, and showed an improvement of about 15% in the bandwidth at Voltage Standing Wave Ratio (VSWR) level of 3. A new systematic rules procedure for extracting the circuit model of transmission lines based structures is proposed and applied in deriving a circuital model for the jig. The EM and developed circuital models are validated versus vectorial scattering parameters and VSWR. The estimation of the uncertainty shows small values at the band of measurement. The developed prototype meets DO-160 and MIL-STD-461E requirements and shows an improved high frequency performance when compared with reliable products. An application is presented in measuring the insertion loss of bulk current injection probe and in illustrating the effect of the shield slot distance on the probe High Frequency (HF) performance. [ABSTRACT FROM AUTHOR]

Global trade relies on the ability to reproducibly and accurately communicate the performance of products and to support these attestations. This standardization is essential for accurate, reproducible, reliable, and communicable characterization of the performance of these devices, to support technology and product advancement, product comparison and performance tracking, and device calibration and traceability. Standard terms and definitions, reproducible test methods, and accurate computational procedures are necessary for this communication and facilitate economic growth and technology evolution through the common understanding of technology. The IEEE Technical Committee 10 (TC-10), the Waveform Generation, Measurement, and Analysis Committee of the IEEE Instrumentation and Measurement Society (IMS), fulfills the global need for standardized terms and test and computational methods for describing and/or measuring the parameters that describe the performance of signal generators and waveform recorders and analyzers. The TC-10 has developed and maintains the following documentary standards: IEEE Std 181-2011, “Standard on Transitions, Pulses, and Related Waveforms” [1]; IEEE Std 1057-2017, “Standard for Digitizing Waveform Recorders” [2]; IEEE Std 1241-2010, “Standard for Terminology and Test Methods for Analog-to-Digital Converters” [3]; IEEE Std 1658-2011, “Standard for Terminology and Test Methods for Digital-to-Analog Converters” [4]; and the IEEE Std 1696-2013, “Standard for Terminology and Test Methods for Circuit Probes” [5]. In development is the IEEE Draft Std P2414 “Draft Standard for Jitter and Phase Noise.” The TC-10 comprises an international group of electronics engineers, mathematicians, professors and physicists with representatives from national metrology laboratories, national science laboratories, component manufacturers, the test instrumentation industry, academia, and end users. The status of the TC-10 standards is described herein. [ABSTRACT FROM AUTHOR]

A novel parameter extraction method for the Schottky diode’s large-signal equivalent-circuit model is proposed, and used to design high-efficiency microwave rectifying circuits. This method extracts the nonlinear SPICE parameters in the equivalent-circuit from measured I-V and C-V data, and the linear parasitic parameters from the broadband small-signal S-parameters. Moreover, it employs a de-embedding technology that adopts an equivalent circuit to remove the influence of the test fixture in the S-parameters measurement, thereby additional TRL calibration kits are not required. As a sample, large-signal equivalent-circuit parameters of the Schottky diode with model number MA4E1317 are extracted by the proposed method. Then it was used to design two Class-F microwave rectifying circuits working at 2.45 GHz and 5.8 GHz, respectively. Owing to the high accuracy of the extracted parameters by the proposed method, the simulation results such as the large-signal transient voltage waveforms across the diode agree well with the measured ones. Furthermore, two rectifying circuits exhibit very high rectifying efficiencies (e.g., 83.5% at 2.45 GHz and 82.1% at 5.8 GHz with 16.8 dBm input power). [ABSTRACT FROM AUTHOR]

The intermittent fault (IF) in electrical systems is considered to be one of the most challenging problems to tackle. At present, there remains a lack of understanding as to the mechanism of IF. Therefore, this letter is focused on the characteristics of IF in electrical connectors under vibration environment. Based on the mechanical structure of a certain kind of electrical connector, a dynamic model is constructed to analyze how its contact resistance varies under vibration environment. In addition, a vibration test rig intended for electrical connectors and a contact resistance acquisition system are developed. Under vibration environment, experiments are conducted on electrical connectors with IF injected. According to the results obtained from both sweep-frequency and fixed-frequency vibration test, some conclusions are summarized regarding the frequency, amplitude, and phase characteristics of the IF in electrical connectors, which is conducive to improving the understanding as to the fundamental mechanism of IF caused by vibration stress. [ABSTRACT FROM AUTHOR]

S-parameter de-embedding methods require multiple fixtures to be identical. However, due to manufacturing variations, the fixtures are never perfectly identical, which violates the assumptions for the de-embedding algorithms and, in turn, introduces errors. In this article, a novel methodology is proposed to estimate the errors due to de-embedding for practical transmission line measurements. The circuit models of the thru and total lines with fixtures are created. Perturbation in the fixtures is introduced based on the fixture variation estimated by time-domain reflectometry measurements. The method can predict the envelope and estimate the confidence interval of the de-embedded insertion loss using a limited number of simulation cases. [ABSTRACT FROM AUTHOR]

The adoption of lighting systems based on light-emitting diode (LED) technologies gains further significance as these technologies become mature, particularly within the context of homes and offices. LED technologies are well known for the superior reliability standards and extended lifetime. Unfortunately, power electronic technologies used to drive LED lighting systems are unable to reach identical levels of longevity. Particularly, active semiconductors pose one of the major hurdles to the full exploitation of the LEDs lifetime. This article proposes a fault-tolerant LED driver, derived from the single-inductor multiple-output (SIMO) topology, which combines the benefits of fault tolerance, multiple and independent fixture control, and full dimming range, on a single LED driver. Two alternative reconfiguration strategies ensure, whenever feasible, that none of the LED fixtures suffer significant depreciation of luminous flux during the postfault driver operation. Simulation and experimental results demonstrate the effectiveness of the proposed fault-tolerant LED driver. [ABSTRACT FROM AUTHOR]

Traditional printed circuit board (PCB) laminates such as FR4 types are formed using epoxy resin and glass fiber. The most important problem with waste PCB laminates is that their recycling cycle is too long. Herein, we aimed to show whether it is possible to use plant-based fibers instead of petroleum-based fibers. In this study, we have fabricated alternative eco-friendly Luffa fiber-reinforced/epoxy PCB (Luffa-PCB) laminates using Luffa fiber instead of glass fiber. We examined the properties of Luffa-PCB laminates for potential applications as PCBs in terms of frequency dependence of dielectric permittivity, capacitance, ac conductivity, impedance, and electric modulus by using impedance spectroscopy method in a frequency ranging from 10 Hz to 10 MHz. Furthermore, we investigated the electrical resistivity properties of Luffa-PCB laminates using electrometer/high resistance meter and resistivity test fixture. All the results were compared with commonly used FR2- and FR4-type PCB laminates. According to the results obtained, it has been found that the produced Luffa-PCB laminates have adequate properties as an alternative to traditional laminates. Thus, a very important step is taken to solve the recycling problem by using plant-based fibers instead of glass fibers. [ABSTRACT FROM AUTHOR]

The classical form of a flexural ultrasonic transducer is a piezoelectric ceramic disc bonded to a circular metallic membrane. This ceramic induces vibration modes of the membrane for the generation and detection of ultrasound. The transducer has been popular for proximity sensing and metrology, particularly for industrial applications at ambient pressures around 1 bar. The classical flexural ultrasonic transducer is not designed for operation at elevated pressures, such as those associated with natural gas transportation or petrochemical processes. It is reliant on a rear seal which forms an internal air cavity, making the transducer susceptible to deformation through pressure imbalance. The application potential of the classical transducer is therefore severely limited. In this study, a venting strategy which balances the pressure between the internal transducer structure and the external environment is studied through experimental methods including electrical impedance analysis and pitch-catch ultrasound measurement. The vented transducer is compared with a commercial equivalent in air towards 90 bar. Venting is shown to be viable for a new generation of low cost and robust industrial ultrasonic transducers, suitable for operation at high environmental pressure levels. [ABSTRACT FROM AUTHOR]

Flexible electronic products are becoming increasingly popular. Because of the large deformation that flexible products encounter, it is important to predict their performance in response to mechanical loadings. This article focuses on the mechanical and electrical behavior of the printed silver conductor under the adaptive curvature flexure test. In the adaptive curvature flexure test, the printed conductor is bent between two rigid parallel plates so that the bending strain will be generated through the conductor and, thus, cause resistance change. The resistance of the conductor was measured continuously by the four-wire method during the test for analysis. A series of conductors with different widths printed on two commonly used substrate materials—polyimide and polyethylene terephthalate—were tested. In the single load–unload tests, the resistance of the conductor increased nonlinearly as the gap distance between the parallel plates decreased. Cracks in the conductor were observed under a strain of approximately 3%. In the cyclic tests, the resistance of the conductor increased linearly with cycles after the first several cycles. In addition to the experimental tests, the strain distribution of the conductor was calculated by both finite-element method and theoretical analysis. Combined with the relationship between the resistivity of the conductor and the bending strain, an integral model has been developed to predict the resistance change of the printed conductor under bending. [ABSTRACT FROM AUTHOR]