| 1. |
- Heidari-Rarani, Mohammad, et al.
(författare)
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Experimental investigation and micromechanics-based damage modeling of tensile failure of polymer concrete reinforced with recycled PET bottles
- 2023
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Ingår i: Engineering Failure Analysis. - : Elsevier BV. - 1350-6307. ; 148
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Tidskriftsartikel (refereegranskat)abstract
- Epoxy-based polymer concretes (PCs) behave in a quasi-brittle manner and suffer from low tensile strength. Adding different kinds of fillers has been widely used to improve the ductility of these materials and change the failure mechanisms. In this study, we used polyethylene terephthalate (PET) fillers from recycled bottles to enhance the tensile strength and ductility of PCs and prevent sudden brittle failure. Two different sizes of fillers (i.e., fine and coarse) are considered and the Brazilian disk configuration is used to measure the indirect tensile strength of reinforced PCs. Experimental results showed that the addition of coarse PET fillers to the PC has more significant effects on tensile strength and failure mechanism than fine PET fillers. Then, micromechanical damage analyses are conducted via finite element simulations of two-dimensional representative volume elements. The effects of void content and recycled PET fillers on the tensile strength and ductility of reinforced PCs were studied in the micromechanical simulations. Since the Brazilian disk examines the indirect tensile behavior, a relationship was proposed between the direct micromechanical tensile strength and the indirect macro mechanical tensile strength. The new procedure is experimentally validated for the prediction of the tensile strength of both reinforced and unreinforced PCs.
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| 2. |
- Kim, Min Seo, et al.
(författare)
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Global burden of peripheral artery disease and its risk factors, 1990-2019 : a systematic analysis for the Global Burden of Disease Study 2019
- 2023
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Ingår i: The Lancet Global Health. - : Elsevier. - 2214-109X. ; 11:10, s. E1553-E1565
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Tidskriftsartikel (refereegranskat)abstract
- Background: Peripheral artery disease is a growing public health problem. We aimed to estimate the global disease burden of peripheral artery disease, its risk factors, and temporospatial trends to inform policy and public measures.Methods: Data on peripheral artery disease were modelled using the Global Burden of Disease, Injuries, and Risk Factors Study (GBD) 2019 database. Prevalence, disability-adjusted life years (DALYs), and mortality estimates of peripheral artery disease were extracted from GBD 2019. Total DALYs and age-standardised DALY rate of peripheral artery disease attributed to modifiable risk factors were also assessed.Findings: In 2019, the number of people aged 40 years and older with peripheral artery disease was 113 million (95% uncertainty interval [UI] 99 center dot 2-128 center dot 4), with a global prevalence of 1 center dot 52% (95% UI 1 center dot 33-1 center dot 72), of which 42 center dot 6% was in countries with low to middle Socio-demographic Index (SDI). The global prevalence of peripheral artery disease was higher in older people, (14 center dot 91% [12 center dot 41-17 center dot 87] in those aged 80-84 years), and was generally higher in females than in males. Globally, the total number of DALYs attributable to modifiable risk factors in 2019 accounted for 69 center dot 4% (64 center dot 2-74 center dot 3) of total peripheral artery disease DALYs. The prevalence of peripheral artery disease was highest in countries with high SDI and lowest in countries with low SDI, whereas DALY and mortality rates showed U-shaped curves, with the highest burden in the high and low SDI quintiles.Interpretation: The total number of people with peripheral artery disease has increased globally from 1990 to 2019. Despite the lower prevalence of peripheral artery disease in males and low-income countries, these groups showed similar DALY rates to females and higher-income countries, highlighting disproportionate burden in these groups. Modifiable risk factors were responsible for around 70% of the global peripheral artery disease burden. Public measures could mitigate the burden of peripheral artery disease by modifying risk factors.
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| 3. |
- Mahshid, Rasoul, et al.
(författare)
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Recent advances in development of additively manufactured thermosets and fiber reinforced thermosetting composites: Technologies, materials, and mechanical properties
- 2023
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Ingår i: Composites Part A: Applied Science and Manufacturing. - 1359-835X. ; 171
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Forskningsöversikt (refereegranskat)abstract
- Additive manufacturing (AM) has a great potential to create complex parts and systems lighter and stronger compared to traditional manufacturing operations. So far, several polymeric materials including different types of thermoset polymers and recently fiber reinforced thermosetting composites have been used in different additive manufacturing processes. Printed parts have shown an enhanced performance compared to their counterparts made by conventional techniques. This review article presents the state-of-the-art in the field of polymer-based additive manufacturing processes employed for thermoset resins, their corresponding fiber reinforced composites, main process parameters, build strategies, and their effects on the mechanical behavior of printed parts. This paper enlightens the basics of material extrusion, vat photopolymerization, and hybrid AM processes. In particular, these techniques involve Direct Ink Writing (DIW), Frontal Polymerization (FP), Reactive Extrusion (RE), In-bath print and cure (IBPC) that fall under extrusion-based AM system, and Stereolithography (SLA), Digital Light Processing (DLP) falling under vat photopolymerization AM.
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