EFFECTS OF NEGATIVE POISSON’S RATIO ON THE MECHANICS OF AUXETIC CARBON FIBER COMPOSITES UNDER TENSILE, BUCKLING AND LOW VELOCITY IMPACT

Carbon fiber reinforced polymer (CFRP) matrix composites exhibited superior properties, such as high specific stiffness and specific strength, excellent fatigue and corrosion resistance, and low coefficient of thermal expansion, have been popular across various industries including aerospace, marine, automotive, energy, civil infrastructure, and high-end sports over the past decades. However, one significant drawback of CFRP composites is the susceptibility to low velocity impact damage which, for aircraft, can be results of tool drop, runway debris, and bird strike during takeoff and landing. These impact events could lead to external and internal damages of a CFRP composite structure in various damage modes, such as fiber breakage, delamination, matrix cracking, which will significantly compromise the structural integrity. Introducing auxeticity or negative Poisson’s ratio is one potential solution to mitigate the low velocity impact damage of CFRP composites, which can be achieved by tailoring the layup of an anisotropic composite laminate. Such special layups involve use of nontraditional ply orientations other than the quad layups with ply orientations of 0°, 90°, +45°, -45°, and the effects of such layups on the other apparent mechanical properties are yet to be investigated. This work aims to investigates the impact of introducing in-plane or out-of-plane auxeticity (negative Poisson’s ratio) in carbon fiber reinforced polymer (CFRP) composite laminates to examine their mechanical performance, particularly under tensile, uni-axial bucking and low velocity impact through both experimental tests and numerical simulations. In this work, the in-plane auxetic and counterpart non-auxetic laminates have a layup of [15/65/15/65/15] and [35/60/-5/60/35]. For out-of-plane auxetic and non-auxetic laminates, the layups are [25/-25/25/-25/25] and [50/0/50/0/50], respectively. Tensile tests on laminates with various in-plane and out-of-plane Poisson’s ratios revealed that auxetic layups could significantly alter ultimate tensile strength. Laminates with in-plane negative Poisson’s ratios demonstrated considerably lower tensile strength (51.7% on average) than their Positive Poisson’s ratio counterparts, whereas out-of-plane auxetic laminates showed moderately lowered (23.1% on average) tensile strength than the counterpart non-auxetic laminates. Strain field analysis, supported by digital image correlation and finite element simulations, highlighted stress concentrations near specimen gage sections, influenced by the unbalanced layup designs. Auxetic laminates were found to have a more imminent first ply failure as well as ultimate tensile failure due to transverse strain aggregation. Experimental findings also reveal that auxetic laminates can triple the buckling strength under uniaxial compression compared to non-auxetic counterparts, attributed to the unique effects of negative Poisson’s ratios. A novel monoclinic plate-based approach was used to isolate the influence of auxeticity from changes in the bending stiffness matrix, confirming that auxeticity actively contributes to enhanced buckling strength, though this effect is sensitive to stiffness matrix elements, as well as the loading conditions and plate aspect ratios. Numerical simulations and experimental tests demonstrate that auxetic laminates experience significantly reduced delamination, matrix compressive damage, and fiber tensile damage under low velocity impacts at higher impact energies. The results underscore the potential of auxetic designs to improve the impact resistance and buckling stability of composite laminates but also highlight the need for careful consideration of other mechanical properties, such as tensile, compressive, and bending strengths. The findings provide critical insights for designing advanced composite structures with enhanced performance, leveraging the benefits of negative Poisson’s ratios while managing trade-offs in other structural properties

Convolutional Neural Networks and Feature Fusion for Flow Pattern Identification of the Subsea Jumper

The gas–liquid two-phase flow patterns of subsea jumpers are identified in this work using a multi-sensor information fusion technique, simultaneously collecting vibration signals and electrical capacitance tomography of stratified flow, slug flow, annular flow, and bubbly flow. The samples are then processed to obtain the data set. Additionally, the samples are trained and learned using the convolutional neural network (CNN) and feature fusion model, which are built based on experimental data. Finally, the four kinds of flow pattern samples are identified. The overall identification accuracy of the model is 95.3% for four patterns of gas–liquid two-phase flow in the jumper. Through the research of flow profile identification, the disadvantages of single sensor testing angle and incomplete information are dramatically improved, which has a great significance on the subsea jumper’s operation safety.publishedVersio

Sparse Online Learning for Collaborative Filtering

With the rapid growth of Internet information, our individual processing capacity has become over-whelming. Thus, we really need recommender systems to provide us with items online in real time. In reality, a user’s interest and an item’s popularity are always changing over time. Therefore, recommendation approaches should take such changes into consideration. In this paper, we propose two approaches, i.e., First Order Sparse Collaborative Filtering (SOCFI) and Second Order Sparse Online Collaborative Filtering (SOCFII), to deal with the user-item ratings for online collaborative filtering. We conduct some experiments on such real data sets as Movie- Lens100K and MovieLens1M, to evaluate our proposed methods. The results show that, our proposed approach is able to effectively online update the recommendation model from a sequence of rating observation. And in terms of RMSE, our proposed approach outperforms other baseline methods

Analysis of Microbial Diversity in Soil under Ginger Cultivation

Ginger is a perennial monocotyledonous herb, which can be used as both a vegetable and a medicinal plant. However, it is susceptible to various plant pathogens. Microbial diversity in soil is related closely to the health and productivity of plant crops including ginger. In the current study, we compared microbial diversity from soil samples under ginger cultivation (disease incidence of >50% [relatively unhealthy sample] versus disease incidence of <10% [relatively healthy sample]). The bacterial and fungal taxa were analyzed by Illumina-based sequencing, with 16S and ITS identification, respectively. Both bacterial and fungal OTUs were significantly more in the healthy soil sample than the unhealthy sample. Moreover, the dominant bacterial and fungal genera were detected to be different in each sample. Rhodanobacter and Kaistobacter were the dominant bacterial genera in the healthy sample, while Rhodoplanes and Bradyrhizobium were the dominant genera in the unhealthy sample. For fungal analysis, Cladosporium, Cryptococcus, and Tetracladium were the dominant genera in the healthy sample, while Lecanicillium, Pochonia, and Rhodotorula were the dominant genera in the unhealthy sample. Collectively, the basic information of microbial diversity in ginger soil is helpful for elucidating the ginger-microbe interactions and potentially selecting suitable plant growth-promoting rhizobacteria and biocontrol agents for ginger production

Efficacy and safety of a NiTi CAR 27 compression ring for end-to-end anastomosis compared with conventional staplers: A real-world analysis in Chinese colorectal cancer patients

OBJECTIVES: This study aimed to evaluate the safety and efficacy of a new nickel-titanium shape memory alloy compression anastomosis ring, NiTi CAR 27, in constructing an anastomosis for colorectal cancer resection compared with conventional staples. METHODS: In total, 234 consecutive patients diagnosed with colorectal cancer receiving sigmoidectomy and anterior resection for end-to-end anastomosis from May 2010 to June 2012 were retrospectively analyzed. The postoperative clinical parameters, postoperative complications and 3-year overall survival in 77 patients using a NiTi CAR 27 compression ring (CAR group) and 157 patients with conventional circular staplers (STA group) were compared. RESULTS: There were no statistically significant differences between the patients in the two groups in terms of general demographics and tumor features. A clinically apparent anastomotic leak occurred in 2 patients (2.6%) in the CAR group and in 5 patients (3.2%) in the STA group (p=0.804). These eight patients received a temporary diverting ileostomy. One patient (1.3%) in the CAR group was diagnosed with anastomotic stricture through an electronic colonoscopy after 3 months postoperatively. The incidence of postoperative intestinal obstruction was comparable between the two groups (p=0.192). With a median follow-up duration of 39.6 months, the 3-year overall survival rate was 83.1% in the CAR group and 89.0% in the STA group (p=0.152). CONCLUSIONS: NiTi CAR 27 is safe and effective for colorectal end-to-end anastomosis. Its use is equivalent to that of the conventional circular staplers. This study suggests that NiTi CAR 27 may be a beneficial alternative in colorectal anastomosis in Chinese colorectal cancer patients

Electrocardiographic features of immune checkpoint inhibitor-associated myocarditis.

Immune checkpoint inhibitors (ICIs) are associated with immune-related adverse events including myocarditis, whilst improving cancer-related outcomes. There is thus a clinical need to identify electrocardiographic manifestations of ICI-related myocarditis to guide clinical management. PubMed was searched for clinical studies and case reports describing electrocardiographic changes in patients with ICI-related myocarditis. A total of six clinical studies and 79 case reports were included. This revealed a range of presentations for patients on ICIs, including supraventricular arrhythmias, ventricular arrhythmias and heart block, and new changes of ST-T segment unrelated to coronary artery disease, ST-segment elevation or depression and T-wave abnormalities. Several patients showed low voltages in multiple leads and new onset Q-wave development. Patients with ICI-related myocarditis may develop new arrhythmia and ST-T changes, and infrequently low voltages in multiple leads. [Abstract copyright: Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.

B vitamins supplementation induced shifts in phytoplankton dynamics and copepod populations in a subtropical coastal area

IntroductionB vitamins play a crucial role in shaping phytoplankton and zooplankton communities in marine ecosystems, yet their impact on community dynamics remains poorly understood.MethodsWe carried out in situ incubation experiments of B vitamins supplementation to explore the response pattern of phytoplankton and zooplankton community compositions.ResultsThe results showed that vitamins B1, B2, B6 and B12 promoted the growth of phytoplankton, and the total Chl α in 87.5% of the supplemented B vitamin treatments showed a significant positive response (p &lt; 0.05). Supplementation with these B vitamins significantly altered the community composition of phytoplankton, and 75% of the B vitamin-supplemented treatments showed an increase in the relative abundance of Minutocellus, Thalassiosirales, Odontella, Prymnesiales and Ditylum, considered mainly to be the result of B vitamin auxotrophy. In contrast, a significant decrease in Copepoda, including Calanoida and Cyclopoida, was observed in 87.5% of treatments. The observed shifts in community composition were attributed to the auxotrophy of certain diatoms and Prymnesiales for B vitamins. These shifts subsequently led to negative correlations (Spearman Rho &lt; -0.8) between the abundance of these phytoplankton species and Copepoda populations.DiscussionThese findings advance our understanding of the complex interactions between micronutrient availability and plankton community dynamics

Sparse online collaborative filtering with dynamic regularization

Abstract(#br)Collaborative filtering (CF) approaches are widely applied in recommender systems. Traditional CF approaches have high costs to train the models and cannot capture changes in user interests and item popularity. Most CF approaches assume that user interests remain unchanged throughout the whole process. However, user preferences are always evolving and the popularity of items is always changing. Additionally, in a sparse matrix, the amount of known rating data is very small. In this paper, we propose a method of online collaborative filtering with dynamic regularization (OCF-DR), that considers dynamic information and uses the neighborhood factor to track the dynamic change in online collaborative filtering (OCF). The results from experiments on the MovieLens100K, MovieLens1M, and HetRec2011 datasets show that the proposed methods are significant improvements over several baseline approaches

Burden of heart failure attributable to chronic kidney disease in older adults (1990–2021): an analysis from the global burden of disease study

BackgroundHeart failure (HF) is a critical global health issue, with chronic kidney disease (CKD) as a significant contributing factor. Both primarily affect older adults, with prevalence rising substantially after age 60. This study examined global trends and disparities in CKD-associated HF among older adults from 1990 to 2021.MethodsUtilizing data from the Global Burden of Disease (GBD) 2021, the study analyzed the prevalence and years lived with disability (YLDs) of CKD-associated HF. Joinpoint regression assessed trends from 1990 to 2021 globally, regionally, and nationally. Health inequity analysis, including the slope index of inequality and health inequality concentration index, evaluated disparities across countries.ResultsFrom 1990 to 2021, the prevalence and YLDs of CKD-associated HF increased globally, with an average annual percentage change (AAPC) of 2.21% [95% confidence interval (CI), 2.17–2.25] and 2.20% (95% CI, 2.16–2.24), respectively. Males exhibited higher prevalence and YLDs but demonstrated a slower increase than females. The low-SDI region exhibited the highest burden, while the high-SDI region showed an unfavorable increase. Socioeconomic disparities were decreased but persisted. From 1990 to 2021, the inequality slope index for prevalence decreased from 143.66 (95% CI, 167.68–119.65) to 114.12 (95% CI, 151.59–76.65), whereas the health inequality concentration index improved from −0.21 (95% CI, −0.30 to −0.12) to −0.07 (95% CI, −0.14 to 0) for prevalence.ConclusionThe global burden of CKD-associated HF has increased substantially, with persistent disparities across gender and SDI levels. Strengthening preventive measures and implementing effective interventions are essential to addressing this escalating health challenge