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The purpose of this paper is to investigate the thermomechanical response of four well-known lead-free die attach materials: sintered silver, sintered nano-copper particles, gold-tin solders and silver-tin transient liquid phase (TLP) bonds.

This examination is conducted through finite element analysis. The mechanical properties of all die attach systems, including elastic and Anand creep parameters, are obtained from relevant literature and incorporated into the numerical analysis. Consequently, the bond stress-strain relationships, stored inelastic strain energies and equivalent plastic strains are thoroughly examined.

The results indicate that silver-tin TLP bonds are prone to exhibiting higher inelastic strain energy densities, while sintered silver and copper interconnects tend to possess higher levels of plastic strains and deformations. This suggests a higher susceptibility to damage in these metallic die attachments. On the other hand, the more expensive gold-based solders exhibit lower inelastic strain energy densities and plastic strains, implying an improved fatigue performance compared to other bonding configurations.

The utilization of different metallic material systems as die attachments in power electronics necessitates a comprehensive understanding of their thermomechanical behavior. Therefore, the results of the present paper can be useful in the die attach material selection in power electronics.

This study aims to focus on the surface mount technology (SMT) mass production process of Sn-9Zn-2.5Bi-1.5In solder. It explores it with some components that will provide theoretical support for the industrial SMT application of Sn-Zn solder.

This study evaluates the properties of solder pastes and selects a more appropriate reflow parameter by comparing the microstructure of solder joints with different reflow soldering profile parameters. The aim is to provide an economical and reliable process for SMT production in the industry.

Solder paste wettability and solder ball testing in a nitrogen environment with an oxygen content of 3,000 ppm meet the requirements of industrial production. The printing performance of the solder paste is good and can achieve a printing rate of 100–160 mm/s. When soldering with a traditional stepped reflow soldering profile, air bubbles are generated on the surface of the solder joint, and there are many voids and defects in the solder joint. A linear reflow soldering profile reduces the residence time below the melting point of the solder paste (approximately 110 s). This reduces the time the zinc is oxidized, reducing solder joint defects. The joint strength of tin-zinc joints soldered with the optimized reflow parameters is close to that of Sn-58Bi and SAC305, with high joint strength.

This study attempts to industrialize the application of Sn-Zn solder and solves the problem that Sn-Zn solder paste is prone to be oxidized in the application and obtains the SMT process parameters suitable for Sn-9Zn-2.5Bi-1.5In solder.

The purpose of this study is to investigate the impact of titanium oxide (TiO₂) filler on the abrasive wear properties of bamboo fiber reinforced epoxy composites (BFRCs) using a Taguchi approach. The study aims to enhance the abrasive wear resistance of these composites by introducing TiO₂ filler as a potential reinforcement, thus contributing to the development of sustainable and environmentally friendly materials.

This study focuses on the fabrication of epoxy/bamboo composites infused with TiO₂ particles within the Wt.% range of 0–8 Wt.% using hand layup techniques. The resulting composites were subjected to wear testing according to ASTM G99-05 standards. Statistical analysis of the wear results was carried out using the Taguchi design of experiments (DOE). Additionally, an analysis of variance (ANOVA) was used to determine the influential control factors impacting the specific wear rate (SWR) and coefficient of friction (COF).

The study illuminates how integrating TiO₂ filler enhances abrasive wear in epoxy/bamboo composites. Statistical analysis of SWR highlights abrasive grit size (grit) as the most influential factor, followed by normal load, Wt.% of TiO₂ and sliding distance. Analysis of the COF identifies normal load as the primary influential factor, followed by grit, Wt.% of TiO₂ and sliding distance. The Taguchi predictive model closely aligns with experimental results, validating its reliability. The morphological study revealed significant differences between the unfilled and TiO₂-filled composites. The inclusion of TiO₂ improved wear resistance, as evidenced by reduced surface damage and wear debris.

This research paper aims to integrate TiO₂ filler and bamboo fibers to create an innovative hybrid composite material. TiO₂ micro and nanoparticles show promise as filler materials, contributing to improved tribological properties of epoxy composites. The utilization of Taguchi’s DOE and ANOVA for statistical analysis provides valuable guidance for academic researchers and practitioners in optimizing control variables, especially in the context of natural fiber reinforced composites.

This study aims to explore the feasibility of adding Si₃N₄ nanoparticles to Sn58Bi and provides a theoretical basis for designing and applying new lead-free solder materials for the electronic packaging industry.

In this paper, Sn58Bi-xSi₃N₄ (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 Wt.%) was prepared for bonding Cu substrate, and the changes in thermal properties, wettability, microstructure, interfacial intermetallic compound and mechanical properties of the composite solder were systematically studied.

The experiment results demonstrate that including Si₃N₄ nanoparticles does not significantly impact the melting point of Sn58Bi solder, and the undercooling degree of solder only fluctuates slightly. The molten solder spreading area reached a maximum of 96.17 mm², raised by 19.41% relative to those without Si₃N₄, and the wetting angle was the smallest at 0.6 Wt.% of Si₃N₄, with a minimum value of 8.35°. When the Si₃N₄ nanoparticles reach 0.6 Wt.%, the solder joint microstructure is significantly refined. Appropriately adding Si₃N₄ nanoparticles will slightly increase the solder alloy hardness. When the concentration of Si₃N₄ reaches 0.6 Wt.%, the joints shear strength reached 45.30 MPa, representing a 49.85% increase compared to those without additives. A thorough examination indicates that legitimately incorporating Si₃N₄ nanoparticles into Sn58Bi solder can enhance its synthetical performance, and 0.6 Wt.% is the best addition amount in our test setting.

In this paper, Si₃N₄ nanoparticles were incorporated into Sn58Bi solder, and the effects of different contents of Si₃N₄ nanoparticles on Sn58Bi solder were investigated from various aspects.

Lead is a well-established environmental contaminant that over the last 50 years has become recognized as a neurotoxin with its greatest concern for the developing child (i.e. both in-utero and postnatally). What is problematic is that children exposed to lead often come from lower socioeconomic status (SES), are largely Black communities and are further at increased risk for developing adverse childhood experiences (ACEs). The literature on ACEs had focused much on trauma, single parenting, child abuse, lack of finances and stress, etc., but has not considered the intersectionality of these ACEs as risk factors within environmental neurotoxic exposures such as lead poisoning. This is important as most low SES communities are Black. In particular, within the New York City Housing Authority (NYCHA), Black families have been neglected of proper lead-abatement to their apartments for nearly 70 years.

This is a viewpoint/perspective paper that examines the lived experiences of Black folxs in NYCHA through a Black critical theory (BlackCrit) and antiblackness framework pertaining to ACEs, and lead poisoning within the NYCHA system of New York City. This perspective paper draws upon the last three years of news reports, five decades of publicly available data sets from NYCHA and the comptroller to raise an awareness of how Black children are treated by NYCHA generation after generation which can be argued as a mass atrocity against NYCHA residents. Furthermore, the systematic and institutionalized racism and environmental injustices by NYCHA and the state can also be considered as a crime against humanity. As such, BlackCrit could help to position awareness, advocacy and knowledge about Black folxs residing in NYCHA to achieve fair, safe and affordable public housing to experience Black joy across future generations.

Thus, rather than civic and state government response efforts focusing their full attention and resources to serving and supporting individuals affected by ACEs they should equally consider the environments in which Black people live and also allocate funds proportionally to address these areas often overlooked. Moreover, proportions of these funds should be redirected especially to lead-abatement and removal of known sources of lead exposures, evaluation of suspected sources of lead exposures (i.e. drinking water, baby food and formula, children’s juice and cereal products, superfund and other waste sites, electronic recycling plants, etc.) and accompanied by all affected children undergoing full and comprehensive neuropsychological testing and follow up studies paid for by the state. The goal should have two fundamental objectives: (1) accepting accountability for failing to address these preventable neuropsychological issues directly affecting Black children generation after generation and (2) offering the proper waived or reimbursable supports and resources to help Black children sustain the best quality of life (QOL) trajectory possible when diagnosed with lead poisoning.

The manuscript is a viewpoint/perspective paper grounded in BlackCrit and an antiblackness framework. There are ample public news reports and public data available from NYCHA on these matters over the last three years. However, the scope of this paper was not to delve too deep into these numbers per se, but rather to address the concerns leading up to and arguably contributing to, at least in part, to these numbers of lead-exposed Black children in NYCHA. Lead poisoning has never been considered as an ACE and its relationship to mass atrocity research is novel which may pave a new avenue for research of this kind through the utility of BlackCrit and antiblackness framework to support and advocate for change so that Black children can be provided with a basic human right of safe housing and experience Black joy.

BlackCrit has not been used in the context of lead poisoning research. Mostly individuals and families of middle- and low-income have been studied in the context of poverty and lead poisoning. However, many people who live in poverty, in public housing, within New York are Black. Thus, Black children are generation after generation exposed to unaddressed lead-abatement and it appears that now more than ever BlackCrit should become the framework for how this work should be discussed in the literature to raise awareness to state governments regarding Black folx's persistent lead poisoning, NYCHA's neglect and mass atrocity research as a long overdue advocacy effort to bring the necessary voice, authentic narrative, and actual knowledge of the lived experiences of Black families in NYCHA with lead poisoning.

The goal of this viewpoint/perspective paper should have two fundamental objectives (1) NYCHA and New York State accepting accountability for failing to address these preventable lead poisoning issues directly affecting Black children; and (2) offering the proper support and resources to help Black children sustain the best QOL trajectory possible when diagnosed with lead poisoning.

Lead poisoning research has never been approached through a mass atrocity and BlackCrit framework and perspective. This is the first report on bridging these fields within the context of NYCHA public housing neglect of lead-abatement and continued poisoning of current and future generations of Black children. This failure of NYCHA lead-abatement contributes annually to economic loss in New York State for many years to come which could be entirely avoided.

This study aims to characterize the mechanical properties of sintered nano-silver under various sintering processes by nano-indentation tests.

Through microstructure observations and characterization, the influences of sintering process on the microstructure evolutions of sintered nano-silver were presented. And, the indentation load, indentation displacement curves of sintered silver under various sintering processes were measured by using nano-indentation test. Based on the nano-indentation test, a reverse analysis of the finite element calculation was used to determine the yielding stress and hardening exponent.

The porosity decreases with the increase of the sintering temperature, while the average particle size of sintered nano-silver increases with the increase of sintering temperature and sintering time. In addition, the porosity reduced from 34.88%, 30.52%, to 25.04% if the ramp rate was decreased from 25°C/min, 15°C/min, to 5°C/min, respectively. The particle size appears more frequently within 1 µm and 2 µm under the lower ramp rate. With reverse analysis, the strain hardening exponent gradually heightened with the increase of temperature, while the yielding stress value decreased significantly with the increase of temperature. When the sintering time increased, the strain hardening exponent increased slightly.

The mechanical properties of sintered nano-silver under different sintering processes are clearly understood.

This paper could provide a novel perspective on understanding the sintering process effects on the mechanical properties of sintered nano-silver.