Fatigue failure of solder joints is one of the major causes of failure in electronic devices. Fatigue life prediction models of solder joints were first put forward in the early 1960s, and since then, numbers of methods were used to model the fatigue mechanism of solder joints. In this article, the majority fatigue life models are summarized, with emphasis on the latest developments in the fatigue life prediction methods. All the models reviewed are grouped into four categories based on the factors affecting the fatigue life of solder joints, which are: plastic strain-based fatigue models, creep damage-based fatigue models, energy-based fatigue models, and damage accumulation-based fatigue models. The models that do not fit any of the above categories are grouped into “other models.” Applications and potential limitations for those models are also discussed.

The pandemic created by SARS-CoV-2 has caused a shortage in the supplies of N95 filtering facepiece respirators (FFRs), disposable respirators with at least 95% efficiency to remove non-oily airborne particles, due to increasing cases all over the world. The current article reviewed various possible decontamination methods for FFR reuse including ultraviolet germicidal irradiation (UVGI), hydrogen peroxide vapor (HPV), microwave-generated steam (MGS), hydrogen peroxide gas plasma (HPGP), and 70% or higher ethanol solution. HPV decontamination was effective against bacterial spores (6 log 10 reduction of Geobacillus stearothermophilus spores ) on FFRs and viruses (> 4 log 10 reduction of various types of viruses) on inanimate surfaces, and no degradation of respirator materials and fit has been reported. 70% or higher ethanol decontamination showed high efficacy in inactivation of coronaviruses on inanimate surfaces (> 3.9 log 10 reduction) but it was lower on FFRs which filtration efficiency was also decreased. UVGI method had good biocidal efficacy on FFRs (> 3 log 10 reduction of H1N1 virus) combined with inexpensive, readily available equipment; however, it was more time-consuming to ensure sufficient reduction in SARS-CoV-2. MGS treatment also provided good viral decontamination on FFRs (> 4 log 10 reduction of H1N1 virus) along with less time-intensive process and readily available equipment while inconsistent disinfection on the treated surfaces and deterioration of nose cushion of FFRs were observed. HPGP was a good virucidal system (> 6 log 10 reduction of Vesicular stomatitis virus ) but filtration efficiency after decontamination was inconsistent. Overall, HPV appeared to be one of the most promising methods based on the high biocidal efficacy on FFRs, preservation of respirator performance after multiple cycles, and no residual chemical toxicity. Nonetheless, equipment cost and time of the HPV process and a suitable operating room need to be considered.

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Hand-arm vibration (HAV), which potentially causes vibration white finger (VWF), and occupational noise are serious issues in the agricultural and forestry industries. Generally, agricultural workers operate as single-family/small businesses and thus are exempted from Occupational Safety and Health Administration (OSHA) regulations/laws for noise and HAV otherwise applicable to other industries in general. The agricultural/forestry sectors are at increased risk as working hours are longer than a typical 8-h work shift putting them at greater risk of hearing loss. The study was conducted to assess the possible association between hearing sensitivity on combined exposure to noise and hand-arm vibration. A systematic literature review was conducted on exposure to noise and HAV in the agricultural/forestry sector and the resulting impacts on hearing. The peer-reviewed articles in English were searched with 14 search words in three databases of PubMed, Ergo Abstracts, and Web of Science without any filter for the year for fully available article text. The database literature search resulted in 72 articles. Forty-seven (47) articles met the search criteria based on the title. Abstracts were then reviewed for any relationship between hearing loss and hand-arm vibration/Raynaud’s phenomenon/VWF. This left 18 articles. It was found that most agricultural workers and chainsaw workers are exposed to noise and VWF. Hearing is impacted by both noise and aging. The workers exposed to HAV and noise had greater hearing loss than non-exposed workers, possibly due to the additive effect on temporary threshold shift (TTS). It was found that VWF might be associated with vasospasm in the cochlea through autonomous vascular reflexes, digital arteries narrowing, vasoconstriction in the inner ear by noise, ischemic damage to the hair cells and increased oxygen demand, which significantly affects the correlation between VWF and hearing loss.

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Abstract.Spinner-disc spreaders are commonly used for application of granular fertilizers with components (divider, spinner-discs, and vanes) influencing material flow behavior and distribution. Fertilizer ricocheting off these components is an uncontrolled aspect of material flow that negatively impacts spread uniformity. Therefore, an investigation using potash (KCl) was conducted to understand the impact of vane shape on fertilizer flow, ricocheting and distribution for a dual-disc spinner spreader. Four different vane shapes were used in this study. The first two vanes (Vanes 1 and 2) were common to this type of spinner spreader with a tapered and open-faced design. However, Vane 1 had a forward tapered top edge at an angle of 32° while Vane 2 had a top edge that was tapered backwards at 15°. Vanes 3 and 4 both had C-channel cross sections with Vane 3 tapered from inside out but Vane 4 had a constant height. Treatments included application rates of 220 and 440 kg/ha using three spinner disc speeds (600, 700, and 800 rpm). Stationary tests were conducted using a collection device that mounted around the spinner discs and vanes in order to estimate fertilizer particle exit points off the vanes. Standard pan tests were conducted to characterize resulting spread patterns, effective spread width, and spread uniformity. Results indicated that the level of ricocheting was significantly impacted by top edge design of a vane and increased with disc speed. The forward, upward facing top edge of Vane 1 caused on average, 26% of the material flow to be ricocheted by the vanes thereby inducing an uncontrolled nature of spread. However, the rearward facing top edge of Vane 2 reduced ricocheting by 13% plus generated a backward particle rotation for those contacting it. The majority of ricocheting occurred when particles contacted the vanes compared to the spinner discs. Ricocheting generated an uncontrollable aspect of the spread pattern with these particles applied along the centerline of the spreader. The effective spread width increased with disc speed. All four vane shapes generated equal effective spread widths of 18.3 and 21.3 m at 600 and 700 rpm, respectively. However, at 800 rpm, Vane 4 generated the greatest effective spread width of 24.4 m compared to 22.9 m for the other three vanes. The wider spread width for Vane 4 was contributed to the rectangular U cross-section maximizing the horizontal velocity of potash particles when exiting the vanes compared to the other three, more open faced vanes. Finally, the spread uniformity varied by vane shape with Vane 2 consistently generating the lowest CVs. Keywords: Distribution, Ricocheting, Vane Design, Spread uniformity, pattern.