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Keywords = internal and packaging stresses

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12 pages, 3788 KiB  
Article
On-Wafer Gate Screening Test for Improved Pre-Reliability in p-GaN HEMTs
by Giovanni Giorgino, Cristina Miccoli, Marcello Cioni, Santo Reina, Tariq Wakrim, Virgil Guillon, Nossikpendou Yves Sama, Pauline Gaillard, Mohammed Zeghouane, Hyon-Ju Chauveau, Maria Eloisa Castagna, Aurore Constant, Ferdinando Iucolano and Alessandro Chini
Micromachines 2025, 16(8), 873; https://doi.org/10.3390/mi16080873 - 29 Jul 2025
Viewed by 383
Abstract
In this paper, preliminary gate reliability of p-GaN HEMTs under high positive gate bias is studied. Gate robustness is of great interest both from an academic and industrial point of view; in fact, different tests and models can be explored to estimate the [...] Read more.
In this paper, preliminary gate reliability of p-GaN HEMTs under high positive gate bias is studied. Gate robustness is of great interest both from an academic and industrial point of view; in fact, different tests and models can be explored to estimate the device lifetime, which must meet some minimum product requirements, as specified by international standards (AEC Q101, JESD47, etc.). However, reliability characterizations are usually time-consuming and are performed in parallel on multiple packaged devices. Therefore, it would be useful to have a faster method to screen out weaker gate trials, already on-wafer, before reaching the packaging step. For this purpose, a room-temperature stress procedure is presented and described in detail. Then, this screening test is applied to devices with a reference gate process, and, as a result, high gate leakage degradation is observed. Afterwards, a different process implementing a dielectric layer between p-GaN and gate metal is evaluated, highlighting the improved behavior during the stress test. However, it is also observed that devices with this process suffer from very high drain leakage, and this effect is then studied and understood through TCAD (technology computer-aided design) simulations. Finally, the effect of a surface treatment performed on the p-GaN is analyzed, showing improved gate pre-reliability while maintaining low drain leakage. Full article
(This article belongs to the Special Issue III–V Compound Semiconductors and Devices, 2nd Edition)
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28 pages, 1971 KiB  
Review
Radon Anomalies and Earthquake Prediction: Trends and Research Hotspots in the Scientific Literature
by Félix Díaz and Rafael Liza
Geosciences 2025, 15(8), 283; https://doi.org/10.3390/geosciences15080283 - 25 Jul 2025
Viewed by 238
Abstract
Radon anomalies have long been explored as potential geochemical precursors to seismic activity due to their responsiveness to subsurface stress variations. However, before this study, the scientific progression of this research domain had not been systematically examined through a quantitative lens. This study [...] Read more.
Radon anomalies have long been explored as potential geochemical precursors to seismic activity due to their responsiveness to subsurface stress variations. However, before this study, the scientific progression of this research domain had not been systematically examined through a quantitative lens. This study presents a comprehensive bibliometric analysis of 379 articles published between 1977 and 2025 and indexed in Scopus and Web of Science. Utilizing the Bibliometrix R-package and its Biblioshiny interface, the analysis investigates temporal publication trends, leading countries, institutions, international collaboration networks, and thematic evolution. The results reveal a marked increase in research output since 2010, with China, India, and Italy emerging as the most prolific contributors. Thematic mapping indicates a shift from conventional geochemical monitoring toward the integration of artificial intelligence techniques, such as decision trees and neural networks, for anomaly detection and predictive modeling. Notwithstanding this methodological evolution, core research themes remain centered on radon concentration monitoring and the analysis of environmental parameters. Overall, the findings highlight the coexistence of traditional and emerging approaches, emphasizing the importance of standardized methodologies and interdisciplinary collaboration. This bibliometric synthesis provides strategic insights to inform future research and strengthen the role of radon monitoring in seismic early warning systems. Full article
(This article belongs to the Section Natural Hazards)
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10 pages, 1770 KiB  
Proceeding Paper
Design and Analysis of Sustainable Kraft Paper-Based Cushioning System for Packaging
by A. P. Mohanraj, S. Kamatchi, A. Deepthisri, P. Parameshwaran and B. P. Sivasubramaniyan
Eng. Proc. 2025, 93(1), 4; https://doi.org/10.3390/engproc2025093004 - 30 Jun 2025
Viewed by 393
Abstract
In this design, foam packaging for consumer products is replaced by the kraft paper cushioning system. The kraft paper is made into a cylindrical structure, with small cylindrical structures pasted to its outer walls. The cylindrical structure can withstand a high amount of [...] Read more.
In this design, foam packaging for consumer products is replaced by the kraft paper cushioning system. The kraft paper is made into a cylindrical structure, with small cylindrical structures pasted to its outer walls. The cylindrical structure can withstand a high amount of stress, internally and externally. These cylindrical structures’ center points make an imaginary equilateral triangle. Therefore, the applied load is distributed equally across the cylinders and hexagonal structures. We can replace foam packaging with this kraft paper packaging. This design is expected to provide a more eco-friendly product than a normal packaging system. The interior design for the kraft paper is created as integrated cylindrical structures designed using Computer Aided Drawing (CAD). Various tests, such as on compression, impact, and vibration, were carried out. In this design, stimulation, cost comparison of the design, and manufacturing feasibility were examined. Full article
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20 pages, 3536 KiB  
Article
Printability Optimization of LDPE-Based Composites for Tool Production in Crewed Space Missions: From Numerical Simulation to Additive Manufacturing
by Federica De Rosa and Susanna Laurenzi
Aerospace 2025, 12(6), 530; https://doi.org/10.3390/aerospace12060530 - 11 Jun 2025
Viewed by 397
Abstract
Fused filament fabrication (FFF) is a 3D printing technology that has been successfully demonstrated aboard the International Space Station (ISS), proving its suitability for space applications. In this study, we aimed to apply FFF to the 3D printing of recycled space beverage packaging, [...] Read more.
Fused filament fabrication (FFF) is a 3D printing technology that has been successfully demonstrated aboard the International Space Station (ISS), proving its suitability for space applications. In this study, we aimed to apply FFF to the 3D printing of recycled space beverage packaging, made of LDPE and a PET-Aluminum-LDPE (PAL) trilaminate. To minimize material waste and optimize the experimental process, we first conducted numerical simulations of additive manufacturing. Using Digimat-AM 2021.1 software, we analyzed residual stresses and warpage in an LDPE/PAL composite with a 10 wt% filler content, processed through the FFF technique. Three key printing parameters, including printing speed and infill pattern, were varied across different levels to assess their impact. Once the optimal combination of parameters for minimizing residual stresses and warpage was identified, we proceeded with the experimental phase, printing objects of increasing complexity to validate the correlation between numerical predictions and the 3D-printed models. The successful fabrication of all geometries under optimized conditions confirmed the numerical predictions, particularly the reduction in warpage and residual stress, validating the material’s viability for additive manufacturing. These findings support the potential application of the LDPE/PAL composite for in situ resource utilization strategies in long-term space missions. Full article
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31 pages, 6902 KiB  
Review
Overview of Research Progress and Application Prospects of Thermal Test Chips
by Lina Ju, Peng Jiang, Yu Ren, Ruiwen Liu, Yanmei Kong, Shichang Yun, Yuxin Ye, Binbin Jiao, Qixing Hao and Honglin Sun
Micromachines 2025, 16(6), 669; https://doi.org/10.3390/mi16060669 - 31 May 2025
Viewed by 3354
Abstract
The development of semiconductor processes and advanced packaging technology has promoted significant advancements in the miniaturization and integration of electronic devices and systems. However, these developments present substantial challenges to the thermal and stress design of current chips, necessitating novel approaches to address [...] Read more.
The development of semiconductor processes and advanced packaging technology has promoted significant advancements in the miniaturization and integration of electronic devices and systems. However, these developments present substantial challenges to the thermal and stress design of current chips, necessitating novel approaches to address these issues. Traditional finite element simulation-assisted design methods have proven inadequate in meeting the demands of highly integrated electronic devices and microsystems due to their inability to effectively simulate the integration process, cross-scale, and multi-physical field coupling. To address these challenges and shorten the design and development period of electronic devices and microsystems, rigorous thermal and stress testing and analyses must be conducted. A promising approach is the utilization of TTC (thermal test chip) technology, a novel in situ testing method, as the primary tool for thermal/stress testing and analyses of the internal interfaces of electronic devices and microsystems. This technology has emerged as a crucial element in validating thermal/stress processes during packaging, as well as in the design of effective heat dissipation solutions. This paper is structured as follows: first, it introduces the principle of thermal test chips; second, it summarizes the domestic and international research progress and index parameter comparison of thermal test chips, as well as the application progress in chip packaging and heat dissipation; and finally, it looks forward to the application prospect of thermal test chips in microsystem design and advanced packaging. Full article
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28 pages, 4957 KiB  
Article
Enhancing Integrated Circuit Quality Control: A CNN-Based Approach for Defect Detection in Scanning Acoustic Tomography Images
by Yung-Tsan Jou, Vicky Pratama Putra, Riana Magdalena Silitonga, Ronald Sukwadi and Maria Magdalena Wahyuni Inderawati
Processes 2025, 13(3), 683; https://doi.org/10.3390/pr13030683 - 27 Feb 2025
Cited by 1 | Viewed by 1624
Abstract
The demand for integrated circuit (IC) chips has risen markedly across various industries in conjunction with advancements in global technology. Prior to packaging, IC elements undergo several processes, including wafer dicing, wire bonding, and encapsulation. Scanning Acoustic Tomography (SAT) effectively analyzes the internal [...] Read more.
The demand for integrated circuit (IC) chips has risen markedly across various industries in conjunction with advancements in global technology. Prior to packaging, IC elements undergo several processes, including wafer dicing, wire bonding, and encapsulation. Scanning Acoustic Tomography (SAT) effectively analyzes the internal structures of integrated circuit products, thereby preventing the supply of defective components, including chip fractures, delamination, voids, and adhesion issues. The study aims to reduce operator eye strain, enhance productivity, and minimize employee turnover rates by proposing the use of convolutional neural networks (CNN) to develop a predictive model for automating defect detection in integrated circuit (IC) products within SAT images, replacing traditional visual inspections. To enhance the accuracy of the CNN model, we implement the flood-fill algorithm as the primary augmentation strategy and create an image augmentation model in Python. This method produces a training set that accurately reflects the true characteristics of defects, thereby mitigating the problem of limited defect data and ensuring the model is trained on reliable information. The incorporation of various rates and scaling factors into SAT defect images, along with the manipulation of the original defect, contributes to the development of a robust dataset suitable for real-world testing. The CNN model is trained using various batch sizes, resulting in customized training datasets and predictive models to improve accuracy. Key findings indicate that employing 40× augmentation alongside a batch size of 32 enhances the model’s performance, yielding a missed detection rate below 0.4% and a false alarm rate of 0.1%. This model offers an improved solution to the issue of manual inspections on assemblies, thereby alleviating operator stress and establishing a robust framework for automated integrated circuit quality management. Full article
(This article belongs to the Section Manufacturing Processes and Systems)
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16 pages, 9350 KiB  
Article
Simulation of Mechanical Stresses in BaTiO3 Multilayer Ceramic Capacitors during Desoldering in the Rework of Electronic Assemblies Using a Framework of Computational Fluid Dynamics and Thermomechanical Models
by Adam Yuile, Erik Wiss, David Barth and Steffen Wiese
Materials 2024, 17(11), 2702; https://doi.org/10.3390/ma17112702 - 3 Jun 2024
Cited by 3 | Viewed by 1158
Abstract
Multilayer ceramic capacitors (MLCCs) are critical components when thermal processes such as reflow desoldering are used during rework of electronic assemblies. The capacitor’s ferroelectric BaTiO3 body is very brittle. Therefore, thermomechanical stresses can cause crack formation and create conductive paths that may [...] Read more.
Multilayer ceramic capacitors (MLCCs) are critical components when thermal processes such as reflow desoldering are used during rework of electronic assemblies. The capacitor’s ferroelectric BaTiO3 body is very brittle. Therefore, thermomechanical stresses can cause crack formation and create conductive paths that may short the capacitor. In order to assess the thermally induced mechanical stresses onto an MLCC during reflow desoldering, simulations were carried out, which make use of a framework of computational fluid dynamics and thermomechanical models within the ANSYS software package. In the first step, CFD simulations were conducted to calculate the transient temperature field in the surrounding of the MLCC component, which was then used as an input for FEM simulations to compute the arising mechanical stresses inside the MLCC. The results of the simulations show that the major contribution to mechanical stresses within the MLCC component comes from the mismatch in thermal expansion between the printed circuit board and the MLCC. The temperature gradients along the MLCC component are rather small and account only for moderate internal stresses within the brittle BaTiO3 body. Full article
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15 pages, 3185 KiB  
Article
Finite-Element Modeling of the Temperature Effect on Extended Avalanche Damage of Gas Main Pipelines
by Nurlan Zhangabay, Ulzhan Ibraimova, Alpysbay Ainabekov, Svetlana Buganova and Arman Moldagaliev
Materials 2024, 17(9), 1963; https://doi.org/10.3390/ma17091963 - 24 Apr 2024
Cited by 6 | Viewed by 1061
Abstract
The dynamic stress–strain state and fracture of a steel main gas pipe section between supports with a straight-through crack was analyzed with consideration of the temperature effect on changes in the mechanical properties of the pipe material. The numerical solution of the problem [...] Read more.
The dynamic stress–strain state and fracture of a steel main gas pipe section between supports with a straight-through crack was analyzed with consideration of the temperature effect on changes in the mechanical properties of the pipe material. The numerical solution of the problem was implemented in the ANSYS-19.2/Explicit Dynamics software package. The process of fracture in a section of the gas pipeline “Beineu–Bozoy–Shymkent” with a linear crack in the temperature range of −40 °C to +50 °C at the operating pressure of 7.5 MPa and critical pressure equal to 9.8 MPa was considered. As a result, it was found that at the initial growth of the internal pressure from working pressure to critical pressure, the length of the crack doubled. At the same time, the process had a local characteristic. Further development of the crack had the nature of avalanche fracture and depended on the temperature of the steel pipeline. With increasing temperature, there was also an increase in the length of the crack at the avalanche fracture. Thus, at a temperature of 40 °C, the crack lengthened 67.75-fold; at a temperature of −10 °C, the crack lengthened 68-fold; at a temperature of +20 °C, the crack lengthened 68.25-fold; and at a temperature of +50 °C, the crack lengthened 68.5-fold. In this work, this difference was 75% of the initial crack length. This fact will be used for further development of the technique of strengthening damaged pipe sections using bandages. Full article
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24 pages, 1810 KiB  
Article
Genetic Basis of Potato Tuber Defects and Identification of Heat-Tolerant Clones
by Sanjeev Gautam, Jeewan Pandey, Douglas C. Scheuring, Jeffrey W. Koym and M. Isabel Vales
Plants 2024, 13(5), 616; https://doi.org/10.3390/plants13050616 - 23 Feb 2024
Cited by 6 | Viewed by 3115
Abstract
Heat stress during the potato growing season reduces tuber marketable yield and quality. Tuber quality deterioration includes external (heat sprouts, chained tubers, knobs) and internal (vascular discoloration, hollow heart, internal heat necrosis) tuber defects, as well as a reduction in their specific gravity [...] Read more.
Heat stress during the potato growing season reduces tuber marketable yield and quality. Tuber quality deterioration includes external (heat sprouts, chained tubers, knobs) and internal (vascular discoloration, hollow heart, internal heat necrosis) tuber defects, as well as a reduction in their specific gravity and increases in reducing sugars that result in suboptimal (darker) processed products (french fries and chips). Successfully cultivating potatoes under heat-stress conditions requires planting heat-tolerant varieties that can produce high yields of marketable tubers, few external and internal tuber defects, high specific gravity, and low reducing sugars (in the case of processing potatoes). Heat tolerance is a complex trait, and understanding its genetic basis will aid in developing heat-tolerant potato varieties. A panel of 217 diverse potato clones was evaluated for yield and quality attributes in Dalhart (2019 and 2020) and Springlake (2020 and 2021), Texas, and genotyped with the Infinium 22 K V3 Potato Array. A genome-wide association study was performed to identify genomic regions associated with heat-tolerance traits using the GWASpoly package. Quantitative trait loci were identified on chromosomes 1, 3, 4, 6, 8, and 11 for external defects and on chromosomes 1, 2, 3, 10, and 11 for internal defects. Yield-related quantitative trait loci were detected on chromosomes 1, 6, and 10 pertaining to the average tuber weight and tuber number per plant. Genomic-estimated breeding values were calculated using the StageWise package. Clones with low genomic-estimated breeding values for tuber defects were identified as donors of good traits to improve heat tolerance. The identified genomic regions associated with heat-tolerance attributes and the genomic-estimated breeding values will be helpful to develop new potato cultivars with enhanced heat tolerance in potatoes. Full article
(This article belongs to the Special Issue Crop Improvement under a Changing Climate)
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18 pages, 3776 KiB  
Article
Global Research on Care-Related Burden and Quality of Life of Informal Caregivers for Older Adults: A Bibliometric Analysis
by Aliya Zhylkybekova, Gulbakit K. Koshmaganbetova, Afshin Zare, Nadiar M. Mussin, Asset A. Kaliyev, Shabnam Bakhshalizadeh, Nurgul Ablakimova, Andrej M. Grjibovski, Natalya Glushkova and Amin Tamadon
Sustainability 2024, 16(3), 1020; https://doi.org/10.3390/su16031020 - 25 Jan 2024
Cited by 7 | Viewed by 8023
Abstract
As global populations continue to undergo demographic aging, the role of caregivers in providing essential support and assistance to older adults has become increasingly prominent. This demographic shift has led to a growing reliance on informal caregivers, often family members, who take on [...] Read more.
As global populations continue to undergo demographic aging, the role of caregivers in providing essential support and assistance to older adults has become increasingly prominent. This demographic shift has led to a growing reliance on informal caregivers, often family members, who take on the responsibilities of caring for older adults. This not only affects immediate family dynamics but also holds broader implications for societal sustainability. The primary objective of this bibliometric analysis is to comprehensively examine the worldwide research output related to the quality of life and caregiver burden among individuals providing care to older adults. By understanding the worldwide research output related to caregivers and their quality of life and burden, we can assess the long-term sustainability of caregiving practices. We retrieved studies with titles containing the terms “caregivers”, “burden”, “quality of life”, and “aged” from the Web of Science (WOS) database. The collected publications were then subjected to analysis using the “bibliometric” package in the R programming environment. A total of 44 publications from 2006–2023 were included in the analysis. Spain emerged as the leading contributor in terms of the number of publications, accounting for 21.9%, followed by the USA at 16.5% and China at 13.6%. The most prolific institution was Kaohsiung Medical University, Taiwan, responsible for 25% of the publications. Among the authors, Cura-Gonzalez I.D. had the highest number of articles, contributing four publications, or 9.1% of the total output. An analysis of co-occurring keywords revealed that the predominant focus of the research revolved around caregiver burden, quality of life, health, care, stress, and impact, reflecting enduring areas of interest within this field. This bibliometric analysis may serve as a tool to provide insights into the current state of research on caregiver burden and quality of life among those caring for older adults. The results of this study can contribute to the assessment of research strategies and the encouragement of global cooperation in the field of care for older adults. By considering the multidimensional nature of caregiving challenges and promoting international cooperation, strides can be made towards sustainable caregiving practices that ensure the wellbeing of both caregivers and the aging population, thus safeguarding the sustainability of healthcare systems worldwide. Full article
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16 pages, 14028 KiB  
Article
The Geometric Configuration of Lubricant Recesses of the Polymer Sliding Layer of the Bearing
by Anastasia P. Bogdanova, Anna A. Kamenskikh and Yuriy O. Nosov
Designs 2023, 7(6), 144; https://doi.org/10.3390/designs7060144 - 18 Dec 2023
Cited by 1 | Viewed by 2219
Abstract
Polymers have gained a foothold in the international market and are actively utilized at a large scale in various industries. They are used as sliding layers in various types of friction units. However, there is a lack of research on their deformation behavior [...] Read more.
Polymers have gained a foothold in the international market and are actively utilized at a large scale in various industries. They are used as sliding layers in various types of friction units. However, there is a lack of research on their deformation behavior under different design conditions. This work is focused on studying the influence of the geometrical design of lubrication recesses in a polymer sliding layer operating under conditions of frictional contact interaction. The article investigated an element of bridge-bearing steel plate with recesses for lubrication. Two geometrical configurations of recesses are studied: the annular groove and spherical well in the engineering software package ANSYS Mechanical APDL. Polytetrafluoroethylene (PTFE) is considered an elastic-plastic sliding layer. A comparative analysis of two models with different geometrical configurations of cutouts for lubrication, with/without taking into account its volume in the recess, has been conducted. The article establishes that in the absence of lubrication in the recesses, large deformations of the polymer sliding layer occur. This effect negatively affects the structure as a whole. Changing the geometry of the recess for lubrication has the greatest effect on the intensity of plastic deformations. Its maximum level is lowered by almost ~60% when spherical notches are used for lubrication instead of grooves. The friction coefficient of the polymer has a great influence on the contact tangential stress. At the experimental coefficient of friction, it is lowered on average by ~85%. The friction coefficient of the lubricant has almost no effect on the deformation of the cell (<1%). Full article
(This article belongs to the Section Civil Engineering Design)
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17 pages, 22693 KiB  
Article
Simulation-Based Analysis of Micro-Damage to Recycled Concrete-Containing Brick Coarse Aggregates
by Lin Qi, Baoyang Yu, Mingxin Yu and Mingyue Zhang
Buildings 2023, 13(9), 2297; https://doi.org/10.3390/buildings13092297 - 9 Sep 2023
Cited by 1 | Viewed by 1366
Abstract
To achieve sustainable development during urbanization, construction waste is recycled for use as an aggregate in recycled concrete (RC). To determine the influence of the brick content in coarse recycled aggregates on the damage sustained by the resultant RC, the RC was first [...] Read more.
To achieve sustainable development during urbanization, construction waste is recycled for use as an aggregate in recycled concrete (RC). To determine the influence of the brick content in coarse recycled aggregates on the damage sustained by the resultant RC, the RC was first divided into seven phases: natural crushed stone, old gravel inside waste concrete, bricks, new mortar, old mortar on waste concrete surfaces, and new and old interface transition zones. The Monte Carlo method was then applied to establish a two-dimensional random aggregate model of the RC made with coarse brick aggregates. The ABAQUS software package was used to simulate a uniaxial compression test, the results of which were combined with those of a macro-test to determine the internal damage change rule of brick-containing RC. The stress–strain curves obtained from the simulation coincided well with that of the macroscopic tests. As the brick content increased, the damage zone inside the specimen and the number of microcracks increased. The stress concentration area decreased, as indicated by a lower compressive strength in the macro-test. The results indicate that higher brick contents in RC yield more initial damage inside the concrete and a lower compressive strength. Full article
(This article belongs to the Special Issue Current Progress of Concrete and Composite Structures)
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49 pages, 13251 KiB  
Article
Survey of Reliability Research on 3D Packaged Memory
by Shuai Zhou, Kaixue Ma, Yugong Wu, Peng Liu, Xianghong Hu, Guojian Nie, Yan Ren, Baojun Qiu, Nian Cai, Shaoqiu Xu and Han Wang
Electronics 2023, 12(12), 2709; https://doi.org/10.3390/electronics12122709 - 17 Jun 2023
Cited by 9 | Viewed by 5538
Abstract
As the core carrier of information storage, a semiconductor memory device is a basic product with a large volume that is widespread in the integrated circuit industry. With the rapid development of semiconductor manufacturing processes and materials, the internal structure of memory has [...] Read more.
As the core carrier of information storage, a semiconductor memory device is a basic product with a large volume that is widespread in the integrated circuit industry. With the rapid development of semiconductor manufacturing processes and materials, the internal structure of memory has gradually shifted from a 2D planar packaging structure to a 3D packaging structure to meet industry demands for high-frequency, high-speed, and large-capacity devices with low power consumption. However, advanced 3D packaging technology can pose some reliability risks, making devices prone to failure, especially when used in harsh environmental conditions, including temperature changes, high temperature and humidity levels, and mechanical stress. In this paper, the authors introduce the typical structure characteristics of 3D packaged memory; analyze the reasons for device failure caused by stress; summarize current research methods that utilize temperature, mechanical and hygrothermal theories, and failure models; and present future challenges and directions regarding the reliability research of 3D packaged memory. Full article
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25 pages, 6803 KiB  
Article
A Tiny Flexible Differential Tension Sensor
by Piotr Z. Wieczorek, Krzysztof Starecki, Krzysztof Gołofit, Maciej Radtke and Marcin Pilarz
Sensors 2023, 23(4), 1819; https://doi.org/10.3390/s23041819 - 6 Feb 2023
Cited by 1 | Viewed by 2236
Abstract
Modern applications of Internet of Things (IoT) devices require cheap and effective methods of measurement of physical quantities. Cheap IoT devices with sensor functionalities can detect a lack or excess of substances in everyday life or industry processes. One possible use of tension [...] Read more.
Modern applications of Internet of Things (IoT) devices require cheap and effective methods of measurement of physical quantities. Cheap IoT devices with sensor functionalities can detect a lack or excess of substances in everyday life or industry processes. One possible use of tension sensors in IoT applications is the automated replenishment process of fast moving consumer goods (FMCG) on shop shelves or home retail automation that allows for quick ordering of FMCG, where the IoT system is a part of smart packaging. For those reasons, a growing demand for cheap and tiny tension sensors has arisen. In this article, we propose a solution of a small flexible tension sensor fabricated in an amorphous InGaZnO (a-IGZO) thin-film process that can be integrated with other devices, e.g., near-field communications (NFC) or a barcode radio frequency identification (RFID) tag. The sensor was designed to magnify the slight internal changes in material properties caused by mechanical stress. These changes affect the dynamic electrical properties of specially designed inverters for a pair of ring oscillators, in which the frequencies become stress-dependent. In the article, we discuss and explain the approach to the optimum design of a ring oscillator that manifests the highest sensitivity to mechanical stress. Full article
(This article belongs to the Section Electronic Sensors)
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26 pages, 8029 KiB  
Article
Engineering Polypropylene–Calcium Sulfate (Anhydrite II) Composites: The Key Role of Zinc Ionomers via Reactive Extrusion
by Marius Murariu, Yoann Paint, Oltea Murariu, Fouad Laoutid and Philippe Dubois
Polymers 2023, 15(4), 799; https://doi.org/10.3390/polym15040799 - 5 Feb 2023
Cited by 3 | Viewed by 3358
Abstract
Polypropylene (PP) is one of the most versatile polymers widely used in packaging, textiles, automotive, and electrical applications. Melt blending of PP with micro- and/or nano-fillers is a common approach for obtaining specific end-use characteristics and major enhancements of properties. The study aims [...] Read more.
Polypropylene (PP) is one of the most versatile polymers widely used in packaging, textiles, automotive, and electrical applications. Melt blending of PP with micro- and/or nano-fillers is a common approach for obtaining specific end-use characteristics and major enhancements of properties. The study aims to develop high-performance composites by filling PP with CaSO4 β-anhydrite II (AII) issued from natural gypsum. The effects of the addition of up to 40 wt.% AII into PP matrix have been deeply evaluated in terms of morphology, mechanical and thermal properties. The PP–AII composites (without any modifier) as produced with internal mixers showed enhanced thermal stability and stiffness. At high filler loadings (40% AII), there was a significant decrease in tensile strength and impact resistance; therefore, custom formulations with special reactive modifiers/compatibilizers (PP functionalized/grafted with maleic anhydride (PP-g-MA) and zinc diacrylate (ZnDA)) were developed. The study revealed that the addition of only 2% ZnDA (able to induce ionomeric character) leads to PP–AII composites characterized by improved kinetics of crystallization, remarkable thermal stability, and enhanced mechanical properties, i.e., high tensile strength, rigidity, and even rise in impact resistance. The formation of Zn ionomers and dynamic ionic crosslinks, finer dispersion of AII microparticles, and better compatibility within the polyolefinic matrix allow us to explain the recorded increase in properties. Interestingly, the PP–AII composites also exhibited significant improvements in the elastic behavior under dynamic mechanical stress and of the heat deflection temperature (HDT), thus paving the way for engineering applications. Larger experimental trials have been conducted to produce the most promising composite materials by reactive extrusion (REx) on twin-screw extruders, while evaluating their performances through various methods of analysis and processing. Full article
(This article belongs to the Special Issue Progress in Polymer Composites for Different Applications)
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