| 1. |
- Abbafati, Cristiana, et al.
(författare)
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- 2020
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Tidskriftsartikel (refereegranskat)
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| 2. |
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| 3. |
- Ahmad Kiadaliri, Aliasghar, et al.
(författare)
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The prevalence of adulthood overweight and obesity in Tehran: findings from Urban HEART-2 study.
- 2015
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Ingår i: Medical Journal of the Islamic Republic of Iran. - 1016-1430. ; 29:178, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND:To estimate and compare prevalence of overweight and obesity among adult people across the 22 districts of Tehran in 2011. METHODS:This was a cross-sectional study using data on 47,406 women and 47,525 men aged≥ 15 years from a large population-based survey (Urban HEART-2). Age-standardized prevalence (ASP) of overweight (25≤BMI<30) and obesity (BMI≥30) were estimated for the Tehran's districts. Pearson Chi2 tests and logistic regression were used to examine any significant differences in prevalence of these disorders across sociodemographic groups. RESULTS: ASPs of overweight were 36.5% and 32.0 % among men and women, respectively (p<0.001). These figures for obesity were 10.7% and 15.3% among men and women, respectively (p<0.001). Crude prevalence of overweight and obesity rose with age up to the age of 54 years and decreased thereafter. Across education groups, the lowest prevalence of overweight/obesity was seen among most educated people. The results showed that being young, single and student were associated with lower odds of overweight/obesity. CONCLUSION:This study showed a high prevalence of overweight and obesity among adult in Tehran. There were significant associations between sociodemographic characteristics and prevalence of overweight/obesity among adults in Tehran. The results of this study might be used in identifying high risk groups of overweight and obesity in Tehran.
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| 4. |
- Alehojat, Mobin, 1982-, et al.
(författare)
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Electron beam-powder bed fusion of Alloy 718 : Effect of hot isostatic pressing and thermal spraying on microstructural characteristics and oxidation performance
- 2020
-
Ingår i: Surface & Coatings Technology. - : Elsevier BV. - 0257-8972 .- 1879-3347. ; 404
-
Tidskriftsartikel (refereegranskat)abstract
- Alloy 718 manufactured via electron beam-powder bed fusion (EB-PBF) was coated with a thermally- sprayed NiCoCrAlY coating for enhanced oxidation protection. A high-velocity air fuel technique was used to deposit the coating. The specimens were then subjected to hot isostatic pressing (HIP). Oxidation of the specimens was undertaken in an ambient air environment at 650 and 800 °C for 168 h. The oxidation performance of EB-PBF-built Alloy 718 was improved after the deposition of the coating, particularly at 800 °C. In this temperature, a thick Cr-rich oxide scale was found on the uncoated Alloy 718 specimen, whereas a thin and stable Al-rich oxide scale was formed on the surface of the coated specimen. HIPing enhanced the oxidation resistance of uncoated Alloy 718; however, the oxidation behavior of coated Alloy 718 was negatively affected by HIPing. © 2020 The Authors
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| 5. |
- Chen, Yang, et al.
(författare)
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Semiconductor nanowire array for transparent photovoltaic applications
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 118:19
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Tidskriftsartikel (refereegranskat)abstract
- The surface area of a building that could potentially be used for Building Integrated Photovoltaics would increase dramatically with the availability of transparent solar cells that could replace windows. The challenge is to capture energy from outside the visible region (UV or IR) while simultaneously allowing a high-quality observation of the outside world and transmitting sufficient light in the visible region to satisfactorily illuminate the interior of the building. In this paper, we show both computationally and experimentally that InP nanowire arrays can have good transparency in the visible region and high absorption in the near-infrared region. We show experimentally that we can achieve mean transparencies in the visible region of 65% and the radiative limit of more than 10% based on measured absorption and calculated emission. Our results demonstrate that nanowire arrays hold promise as a method to achieve transparent solar cells, which would fulfill the requirements to function as windows. In addition, we show that by optical design and by designing the geometry of nanowire arrays, solar cells can be achieved that absorb/transmit at wavelengths that are not decided by the bandgap of the material and that can be tailored to specific requirements such as colorful windows.
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| 6. |
- Gómez, Víctor J., et al.
(författare)
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Wafer-scale nanofabrication of sub-100 nm arrays by deep-UV displacement Talbot lithography
- 2020
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Ingår i: Nanotechnology. - : IOP Publishing. - 0957-4484 .- 1361-6528. ; 31:29
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Tidskriftsartikel (refereegranskat)abstract
- In this manuscript, we demonstrate the potential of replacing the standard bottom anti-reflective coating (BARC) with a polymethylglutarimide (PMGI) layer for wafer-scale nanofabrication by means of deep-UV displacement talbot lithography (DTL). PMGI is functioning as a developable non-UV sensitive bottom anti-reflective coating (DBARC). After introducing the fabrication process using a standard BARC-based coating and the novel PMGI-based one, the DTL nanopatterning capabilities for both coatings are compared by means of the fabrication of etched nanoholes in a dielectric layer and metal nanodots made by lift-off. Improvement of DTL capabilities are attributed to a reduction of process complexity by avoiding the use of O2 plasma etching of the BARC layer. We show the capacity of this approach to produce nanoholes or nanodots with diameters ranging from 95 to 200 nm at a wafer-scale using only one mask and a proper exposing dose. The minimum diameter of the nanoholes is reduced from 118 to 95 nm when using the PMGI-based coating instead of the BARC-based one. The possibilities opened by the PMGI-based coating are illustrated by the successful fabrication of an array of nanoholes with sub-100 nm diameter for GaAs nanowire growth on a 2″ GaAs wafer, a 2″ nanoimprint lithography (NIL) master stamp, and an array of Au nanodots made by lift-off on a 4″ silica wafer. Therefore, DTL possess the potential for wafer-scale manufacturing of nano-engineered materials.
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| 7. |
- Jafari Jam, Reza
(författare)
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Advanced patterning and processing for III-V nanowire device fabrication
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Semiconductor nanowires are widely considered as promising candidates for next generations of electronics and optoelectronics. Gold seed particles have so far been recognized as the most important catalyst for growth of nanowires. Costs related to substrates, lithography processes and gold consumption most strongly influence the final cost of nanowire-based devices. An optimum gold deposition process can facilitate reuse of substrates, avoid repetitive lithography processes and reduce the gold consumption in order to reduce the cost of the final device. Moreover, a novel deposition process is needed to deposit gold seeds in complex nanoscale templates used for guided growth of nanowires, and subsequent device fabrication, on commercially viable (001)-oriented Si and SOI substrates.In this work, we report on nanowire seed definition by gold electrodeposition. Electron microscopy inspection and optical spectroscopy confirm that the subsequently grown III-V nanowires have surface morphology and crystal quality comparable to those of nanowires grown from seed particles defined by conventional thermal evaporation. For seeding of substrates used in a typical growth run, we used around 650 times less gold compared to thermal evaporation. We also demonstrated the possibility of depositing seed particles in deep holes etched in thick templates to facilitate template-assisted growth of nanowires on (001) Si and InP substrates. In addition to a functional p-n junction on an (001) InP substrate, the first reported InP-InAs-InP axial heterostructures on an (001) substrate was demonstrated.In order to reuse the substrate for multiple growth runs, growth of AlAs-GaAs nanowires for epitaxial lift-off was realized. Using selective gold electrodeposition, we demonstrated deposition of seed particles on a substrate after nanowire peel-off. AlAs-GaAs nanowires were subsequently regrown demonstrating the potential of this novel technique for substrate reuse.
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| 8. |
- Jafari Jam, Reza
(författare)
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Gold Electrodeposition in Semiconductor Nanowire Technology
- 2017
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Semiconductor nanowires are widely considered as promising candidates for next generations of electronics and optoelectronics. Gold seed particles have so far been recognized as the most important catalyst for growth of nanowires. Costs related to substrates, lithography processes and gold consumption most strongly influence the final cost of nanowire-based devices. An optimum gold deposition process can facilitate re-use of substrates, avoid repetitive lithogra-phy processes and reduce the gold consumption in order to reduce the cost of the final device. In this work, we report on nanowire seed definition by gold electrodeposition. Electron microscopy inspection and optical spectroscopy confirm that the subsequently grown III-V nanowires have surface morphology and crystal quality comparable to those of nanowires grown from seed particles defined by conventional thermal evaporation. For seeding of substrates used in a typical growth run, we used around 650 times less gold with a 10 times higher throughput as compared to thermal evaporation. Using selective gold electrodeposition, we demonstrated redeposition of seed particles on a substrate after nanowire peel-off in order to reuse it for multiple growth runs. We also demonstrated the possibility of depositing seed particles in deep holes etched in thick masks to facilitate template-assisted growth of nanowires on (001) substrates.
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| 9. |
- Jafari Jam, Reza, et al.
(författare)
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III-V nanowire synthesis by use of electrodeposited gold particles
- 2015
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Ingår i: Nano letters (Print). - Washington, DC : American Chemical Society (ACS). - 1530-6984 .- 1530-6992. ; 15:1, s. 134-138
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Tidskriftsartikel (refereegranskat)abstract
- Semiconductor nanowires are great candidates for building novel electronic devices. Considering the cost of fabricating such devices, substrate reuse and gold consumption are the main concerns. Here we report on implementation of high throughput gold electrodeposition for selective deposition of metal seed particles in arrays defined by lithography for nanowire synthesis. By use of this method, a reduction in gold consumption by a factor of at least 300 was achieved, as compared to conventional thermal evaporation for the same pattern. Because this method also facilitates substrate reuse, a significantly reduced cost of the final device is expected. We investigate the morphology, crystallography, and optical properties of InP and GaAs nanowires grown from electrodeposited gold seed particles and compare them with the properties of nanowires grown from seed particles defined by thermal evaporation of gold. We find that nanowire synthesis, as well as the material properties of the grown nanowires are comparable and quite independent of the gold deposition technique. On the basis of these results, electrodeposition is proposed as a key technology for large-scale fabrication of nanowire-based devices.
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| 10. |
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| 11. |
- Jafari Jam, Reza, et al.
(författare)
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Template-assisted vapour-liquid-solid growth of InP nanowires on (001) InP and Si substrates
- 2020
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Ingår i: Nanoscale. - Cambridge : Royal Society of Chemistry. - 2040-3364 .- 2040-3372. ; 12:2, s. 888-894
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Tidskriftsartikel (refereegranskat)abstract
- We report on the synthesis of vertical InP nanowire arrays on (001) InP and Si substrates using template-assisted vapour-liquid-solid growth. A thick silicon oxide layer was first deposited on the substrates. The samples were then patterned by electron beam lithography and deep dry etching through the oxide layer down to the substrate surface. Gold seed particles were subsequently deposited in the holes of the pattern by the use of pulse electrodeposition. The subsequent growth of nanowires by the vapour-liquid-solid method was guided towards the [001] direction by the patterned oxide template, and displayed a high growth yield with respect to the array of holes in the template. In order to confirm the versatility and robustness of the process, we have also demonstrated guided growth of InP nanowire p-n junctions and InP/InAs/InP nanowire heterostructures on (001) InP substrates. Our results show a promising route to monolithically integrate III-V nanowire heterostructure devices with commercially viable (001) silicon platforms.
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| 12. |
- Jafari, Reza, et al.
(författare)
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High-temperature corrosion performance of HVAF-sprayed NiCr, NiAl, and NiCrAlY coatings with alkali sulfate/chloride exposed to ambient air
- 2019
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Ingår i: Corrosion Science. - : Elsevier BV. - 0010-938X .- 1879-0496. ; 160
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Tidskriftsartikel (refereegranskat)abstract
- The high-temperature corrosion of high velocity air-fuel (HVAF) thermal spray Ni21Cr, Ni5Al, and Ni21Cr7AlY coatings was investigated at 600 °C for 168 h in ambient air under KCl and 50-50 mol% KCl–K2SO4 salts. Chlorination-oxidation cycle and breakdown of the corrosion products layer were the dominant corrosion mechanism in the chromia-forming Ni21Cr and Ni21Cr7AlY coatings exposed to KCl. KCl–K2SO4 was less corrosive to the chromia-forming coatings as K2SO4 was less reactive to the protective Cr-rich oxide. The alumina-forming NiAl exhibited a better corrosion performance under KCl, though it partially suffered from selective sulfidation when exposed to the mixed salt. © 2019 Elsevier Ltd
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| 13. |
- Jafari, Reza, et al.
(författare)
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KCl-Induced High Temperature Corrosion Behavior of HVAF-Sprayed Ni-Based Coatings in Ambient Air
- 2018
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Ingår i: Journal of thermal spray technology (Print). - : Springer Science and Business Media LLC. - 1059-9630 .- 1544-1016. ; 27:3, s. 500-511
-
Tidskriftsartikel (refereegranskat)abstract
- KCl-induced high temperature corrosion behavior of four HVAF-sprayed Ni-based coatings (Ni21Cr, Ni5Al, Ni21Cr7Al1Y, and Ni21Cr9Mo) under KCl deposit has been investigated in ambient air at 600°C up to 168h. The coatings were deposited onto 16Mo3 steel - a widely used boiler tube material.Uncoated substrate, 304L and Sanicro25 were used as reference materials in the test environment.SEM/EDS and XRD techniques were utilized to characterize the as-sprayed and exposed samples.The results showed that the small addition of KCl significantly accelerated degradation to the coatings. All coatings provided better corrosion resistance compared to the reference materials. The alumina-forming Ni5Al coating under KCl deposit was capable of forming a more protective oxide scale compared to the chromia-forming coatings as penetration of Cl through diffusion paths was hindered. Both active corrosion and chromate formation mechanisms were found to be responsible for Page 1 of 23ASM the corrosion damages. The corrosion resistance of the coatings based on the microstructure analysis and kinetics had the following ranking (from the best to worst): Ni5Al >Ni21Cr> Ni21Cr7Al1Y>Ni21Cr9Mo.
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| 14. |
- Jafari, Seyyed Reza, et al.
(författare)
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Adaptive multi-objective control allocation with online actuator selection for over-actuated systems
- 2023
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Ingår i: International Journal of Dynamics and Control. - : Springer Nature. - 2195-268X .- 2195-2698. ; 11:3, s. 1220-1229
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents an adaptive control allocation technique for over-actuated systems. The online actuator selection algorithm is used to select the best group of actuators. Also, a multi-objective cost function is utilized for the allocation unit. The virtual and actual control signals in the control allocation methodologies are linked by the effectiveness matrix. In many practical systems, the elements of the effectiveness matrix may vary due to changing operating conditions, nonlinearities, ageing, disturbances and faults. Hence, an online algorithm for estimation of the entries of the effectiveness matrix is presented in this paper. Estimation of the effectiveness matrix will be used for the proposed adaptive actuator selection strategy, employing the Actuator Effectiveness Index (AEI). The AEI is calculated for all the actuators, and the best group of actuators will be subsequently selected. Finally, simulation results are used to show the effectiveness of the proposed methodology.
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| 15. |
- Kebria, Mohammad Reza Shirzad, et al.
(författare)
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Hyper-branched dendritic structure modified PVDF electrospun membranes for air gap membrane distillation
- 2020
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Ingår i: Desalination. - : ELSEVIER. - 0011-9164 .- 1873-4464. ; 479, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Dendrimers are a new class of polymeric materials owning unique properties such as hydrophobicity. In this study, hydrophobic hyper-branched dendritic (HB-Den) structures were synthesized via a polycondensation reaction between hydroxyl groups of boehmite and carboxylic groups of nitrilotriacetic acid (NTA) and was used to improve the hydrophobicity of electrospun nanofibrous membranes (ENMs). Effects of the different contents of HB-Den structures on membrane morphology, elemental properties, surface hydrophobicity, desalination performance and antifouling properties were assessed by field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), water contact angle measurements and air gap membrane distillation (AGMD) experiments. Digital microscopy images showed monodisperse dendrimers with a tree-like structure. The water contact angle and liquid entry pressure (LEP) increased from around 129.3 degrees and 101 +/- 3.1 kPa for a neat PVDF membrane to 138.3 degrees and 121 +/- 2.2 kPa upon loading with 0.075 wt% HB-Den structures. FTIR analysis of the HB-Den containing ENMs confirmed the presence of carboxylic groups of NTA on the membrane surface. After desalination experiments, the 0.075 wt% HB-Den ENM showed a stable flux of 10.7 kg/m(2) h and 99.9% NaCl rejection over 15 h filtration of a 3.5 g/l NaCI solution. The anti-fouling properties of the ENMs were also enhanced by incorporation of the dendritic structures. The 0.075 wt% HB-Den ENM showed flux recovery of about 94% after 20 h desalination experiment using real seawater as a feed solution.
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| 16. |
- Kharaziha, Pedram, et al.
(författare)
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Improvement of liver function in liver cirrhosis patients after autologous mesenchymal stem cell injection : a phase I-II clinical trial
- 2009
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Ingår i: European Journal of Gastroenterology and Hepathology. - 0954-691X .- 1473-5687. ; 21:10, s. 1199-1205
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: End-stage liver disease is a medical problem with high morbidity and mortality. We have investigated the feasibility, safety, and efficacy of using autologous mesenchymal stem cells (MSCs) as a treatment. METHODS: Eight patients (four hepatitis B, one hepatitis C, one alcoholic, and two cryptogenic) with end-stage liver disease having Model for End-Stage Liver Disease score > or =10 were included. Autologous MSCs were taken from iliac crest. Approximately, 30-50 million MSCs were proliferated and injected into peripheral or the portal vein. Liver function and clinical features were evaluated at baseline and 1, 2, 4, 8, and 24 weeks after injection. RESULTS: Treatment was well tolerated by all patients. Liver function improved as verified by the Model for End-Stage Liver Disease score, which decreased from 17.9±5.6 to 10.7±6.3 (P<0.05) and prothrombin complex from international normalized ratio 1.9±0.4 to 1.4±0.5 (P<0.05). Serum creatinine decreased from 114±35 to 80±18 µmol/l (P<0.05). Serum albumin changed from 30±5 to 33±5 g/l and bilirubin from 46±29 to 41±31 µmol/l. No adverse effects were noted. CONCLUSION: Our data show that MSCs injection can be used for the treatment of end-stage liver disease with satisfactory tolerability. Furthermore, this treatment may improve clinical indices of liver function in end-stage liver disease.
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| 17. |
- Li, Jun, et al.
(författare)
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Tolerance of metal halide perovskites to mechanical treatment enables the fabrication of patterned luminescence nano- and microstructures
- 2022
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Ingår i: Materials Advances. - : Royal Society of Chemistry (RSC). - 2633-5409. ; 27:35
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Tidskriftsartikel (refereegranskat)abstract
- Metal halide perovskites have shown a great performance in a broad range of optoelectronic devices. The variety of preparation methods makes perovskites especially attractive, yet preparation of complex nanostructures based on these materials remains challenging. Here we present a template assisted method allowing to achieve any pre-designed arrangement of methylammonium lead triiodide (MAPbI3) polycrystalline patterns with the spatial resolution defined by the template. We utilized a Si/SiO2 wafer with circular 180 nm deep recesses with diameters ranging from 200 to 1600 nm as a template. A polycrystalline perovskite powder was obtained by scratching off a thin perovskite film and mechanically introduced into the patterned template as a pigment. Scanning electron microscopy revealed that the recesses are filled with tightly packed sub-20 nm crystallites. Considering that the spin-coated film used as a source of MAPbI3 consisted of grains up to 2000 nm in diameter suggests that the initially prepared grains were crashed by rubbing to much smaller crystallites. In spite of this harsh mechanical treatment, the filled recesses showed a strong photoluminescence signal, demonstrating the applicability of this approach for the fabrication of diverse nanophotonic structures.
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| 18. |
- Löfstrand, Anette, et al.
(författare)
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Directed Self‐Assembly for Dense Vertical III–V Nanowires on Si and Implications for Gate All‐Around Deposition
- 2022
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Ingår i: Advanced Electronic Materials. - : Wiley. - 2199-160X. ; 8:9
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Tidskriftsartikel (refereegranskat)abstract
- Fabrication of next generation transistors calls for new technological requirements, such as reduced size and increased density of structures. Development of cost‐effective processing techniques to fabricate small‐pitch vertical III–V nanowires over large areas will be an important step toward realizing dense gate all‐around transistors, having high electron mobility, and low power consumption. It is demonstrated here, how arrays of III–V nanowires with a controllable number of rows, ranging from one single row up to bands of 500 nm, can be processed by directed self‐assembly (DSA) of block copolymer (BCP). Furthermore, it is shown that the DSA‐orientation with respect to the substrate's crystal direction affects the nanowire facet configuration, and thereby the nanowire spacing and gate all‐around deposition possibilities. A high χ poly(styrene)‐block‐poly(4‐vinylpyridine) BCP pattern directed by electron beam lithography‐defined guiding lines is transferred into silicon nitride. The silicon nitride is then used as a selective area metal‐organic vapor phase epitaxy mask atop an indium arsenide (InAs) buffer layer on a silicon platform to grow vertical InAs nanowires at 44–60 nm row pitch. Finally, deposition of high‐κ oxide and titanium nitride at this high pattern density is demonstrated, to further illustrate the considerations needed for next generation transistors. Directed self‐assembly of block copolymers is a cost‐effective technique suitable for high patterning densities. Here it is used to enable vertical III–V nanowire growth at ≈54 nm row pitch on a silicon platform in two different nanowire configurations. Furthermore, a path for gate all‐around deposition is explored, which could be of use for small footprint vertical transistor fabrication.
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| 19. |
- Löfstrand, Anette, et al.
(författare)
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Poly(styrene)- block-Maltoheptaose Films for Sub-10 nm Pattern Transfer : Implications for Transistor Fabrication
- 2021
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Ingår i: ACS Applied Nano Materials. - : American Chemical Society (ACS). - 2574-0970. ; 4:5, s. 5141-5151
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Tidskriftsartikel (refereegranskat)abstract
- Sequential infiltration synthesis (SIS) into poly(styrene)-block-maltoheptaose (PS-b-MH) block copolymer using vapors of trimethyl aluminum and water was used to prepare nanostructured surface layers. Prior to the infiltration, the PS-b-MH had been self-assembled into 12 nm pattern periodicity. Scanning electron microscopy indicated that horizontal alumina-like cylinders of 4.9 nm diameter were formed after eight infiltration cycles, while vertical cylinders were 1.3 nm larger. Using homopolymer hydroxyl-terminated poly(styrene) (PS-OH) and MH films, specular neutron reflectometry revealed a preferential reaction of precursors in the MH compared to PS-OH. The infiltration depth into the maltoheptaose homopolymer film was found to be 2.0 nm after the first couple of cycles. It reached 2.5 nm after eight infiltration cycles, and the alumina incorporation within this infiltrated layer corresponded to 23 vol % Al2O3. The alumina-like material, resulting from PS-b-MH infiltration, was used as an etch mask to transfer the sub-10 nm pattern into the underlying silicon substrate, to an aspect ratio of approximately 2:1. These results demonstrate the potential of exploiting SIS into carbohydrate-based polymers for nanofabrication and high pattern density applications, such as transistor devices.
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| 20. |
- Löfstrand, Anette, et al.
(författare)
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Sequential infiltration synthesis and pattern transfer using 6 nm half-pitch carbohydrate-based fingerprint block copolymer
- 2021
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Ingår i: Advances in Patterning Materials and Processes XXXVIII. - : SPIE. - 1996-756X .- 0277-786X. - 9781510640573 - 9781510640580 ; 11612
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Konferensbidrag (refereegranskat)abstract
- This study presents how sequential infiltration synthesis of trimethyl aluminium and water into a carbohydrate-based block copolymer was used to enable pattern transfer of 6 nm half-pitch horizontal cylinders into silicon. Specular neutron reflectometry measurements of poly(styrene)-block-maltoheptaose self-assembled into horizontal cylinders indicate an increasing content of alumina after each sequential infiltration cycle, comparing 0, 1, 2, and 4 cycles, with alumina content reaching 2.4 vol% after four infiltrations cycles. Dry etching processes in inductively coupled plasma reactive ion etching for sub-10 nm patterns were developed, using a two-step technique: O2-plasma for polymer removal and a reactive ion etching of Si using a mixture of SF6 and C4F8 gases. Etch selectivity of more than 2:1 of silicon over alumina-like etch mask material was achieved. To evaluate the etching process, the etched Si structures were measured and characterized by scanning electron microscopy. These results are expected to be of use for nanofabrication and applications in the sub-10 nm regime.
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| 21. |
- Mobaraki, H. A., et al.
(författare)
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Dynamic analysis of a laminated composite plate coupled with a piezoelectric energy harvester and traversed by a moving vehicle
- 2022
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Ingår i: Mechanics of Advanced Materials and Structures. - : Informa UK Limited. - 1537-6532 .- 1537-6494. ; 29:27, s. 6835-6853
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Tidskriftsartikel (refereegranskat)abstract
- The dynamic analysis is carried out of a laminated composite plate coupled with a piezoelectric energy harvester under the action of a moving vehicle. The finite element method along with Newmark’s method are applied to solve the discretized equations. Results are presented for two main cases: (i) free and forced vibrations of the laminated composite plate with no harvester and (ii) forced vibrations of the plate coupled with the energy harvester. Several parameters–such as the symmetric and anti-symmetric layups, length of the harvester, and piezoelectric material parameters–are considered to study their effects on the electrical output.
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| 22. |
- Mobaraki, H. A., et al.
(författare)
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Forced vibration analysis of laminated composite plates under the action of a moving vehicle
- 2022
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Ingår i: Frattura ed Integrita Strutturale. - 1971-8993. ; 16:59, s. 198-211
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a finite element analysis of laminated composite plates under the action of a moving vehicle. The vehicle is modeled as a rigid body with four suspension systems, each consisting of a springdashpot. Overall, the vehicle possesses three degrees of freedom: vertical, rolling, and pitching motions. The equations of motion of the plate are deduced based on first-order shear deformation theory. Using the EulerLagrange equations, the system of coupled equations of motion is extracted and solved by using the Newmark time discretization scheme. The algorithm is validated through the comparison of both the free and forced vibration results provided by the present model and exact or numerical results reported in the literature. The effects are investigated of several system parameters on the dynamic response.
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| 23. |
- Naeini, Hassan Sadeghi, et al.
(författare)
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Playground injuries in children
- 2011
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Ingår i: Open Access Journal of Sports Medicine. - UK : Dovepress. - 1179-1543. ; 2, s. 61-68
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Tidskriftsartikel (refereegranskat)abstract
- Background: Rapid urbanization and unplanned population development can be detrimentalto the safety of citizens, with children being a particularly vulnerable social group. In this review, we assess childhood playground injuries and suggest safety mechanisms which could be incorporated into playground planning.Methods: Inclusion criteria were “children” as the focus group, “playground” as the main field of study, and “unintentional injury” and “safety” as the concepts of study. The keywords used for the PubMed search were “playground”, “children”, and “injury”. Initially we accessed 182 articles. After screening according to inclusion criteria, 86 articles were found, and after reading the abstracts and then the full text, 14 articles were finally included for analysis. The papers reviewed included four case-control studies, three case studies, three descriptive studies, two interventional studies, one retrospective study, one cross-sectional study, and one systematic review.Results: Playground-related fractures were the most common accidents among children, underscoring the importance of safety promotion and injury prevention in playgrounds, lowrisk equipment and playing hours (week days associated with higher risk), implementation of standards, preventing falls and fall-related fractures, and addressing concerns of parents about unsafe neighborhoods. With the exception of one study, all of the reviewed papers had not implemented any practical safety plan. Safe engineering approaches were also ignored.Conclusion: We recommend a systematic safety approach based on the “safety circle” which includes three main areas, ie, equipment, environment, and children.
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| 24. |
- Sadeghi, Esmaeil, 1985-, et al.
(författare)
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Subsurface grain refinement in electron beam-powder bed fusion of Alloy 718 : Surface texture and oxidation performance
- 2020
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Ingår i: Materials Characterization. - : Elsevier. - 1044-5803 .- 1873-4189. ; 168
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Tidskriftsartikel (refereegranskat)abstract
- Subsurface grains of Alloy 718 additively manufactured via electron beam-powder bed fusion technique were refined using shot peening to improve the surface texture and oxidation performance. Oxidation of the specimens was performed at 650 and 800 degrees C in ambient air. Due to plastic deformation upon shot peening, compressive residual stress and high microstrain were generated in the subsurface region within a depth of approximately 50 mu m. The shot-peened specimen exhibited lower surface roughness, finer subsurface grains, and higher hardness compared to the as-built specimen. Shot peening, coupled with hot isostatic pressing and heat treatment (HIP-HT), yielded superior oxidation performance with substantially low oxidation kinetics at 800 degrees C. The smooth surface, as well as dense and refined subsurface microstructure resulting from shot peening, facilitated the formation of a continuous, protective, and adherent Cr-rich oxide scale.
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| 25. |
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| 26. |
- Sepanlou, Sadaf G., et al.
(författare)
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The global, regional, and national burden of cirrhosis by cause in 195 countries and territories, 1990-2017 : a systematic analysis for the Global Burden of Disease Study 2017
- 2020
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Ingår i: The Lancet Gastroenterology & Hepatology. - 2468-1253. ; 5:3, s. 245-266
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Tidskriftsartikel (refereegranskat)abstract
- Background Cirrhosis and other chronic liver diseases (collectively referred to as cirrhosis in this paper) are a major cause of morbidity and mortality globally, although the burden and underlying causes differ across locations and demographic groups. We report on results from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2017 on the burden of cirrhosis and its trends since 1990, by cause, sex, and age, for 195 countries and territories. Methods We used data from vital registrations, vital registration samples, and verbal autopsies to estimate mortality. We modelled prevalence of total, compensated, and decompensated cirrhosis on the basis of hospital and claims data. Disability-adjusted life-years (DALYs) were calculated as the sum of years of life lost due to premature death and years lived with disability. Estimates are presented as numbers and age-standardised or age-specific rates per 100 000 population, with 95% uncertainty intervals (UIs). All estimates are presented for five causes of cirrhosis: hepatitis B, hepatitis C, alcohol-related liver disease, non-alcoholic steatohepatitis (NASH), and other causes. We compared mortality, prevalence, and DALY estimates with those expected according to the Socio-demographic Index (SDI) as a proxy for the development status of regions and countries. Findings In 2017, cirrhosis caused more than 1.32 million (95% UI 1.27-1.45) deaths (440000 [416 000-518 000; 33.3%] in females and 883 000 [838 000-967 000; 66.7%] in males) globally, compared with less than 899 000 (829 000-948 000) deaths in 1990. Deaths due to cirrhosis constituted 2.4% (2.3-2.6) of total deaths globally in 2017 compared with 1.9% (1.8-2.0) in 1990. Despite an increase in the number of deaths, the age-standardised death rate decreased from 21.0 (19.2-22.3) per 100 000 population in 1990 to 16.5 (15.8-18-1) per 100 000 population in 2017. Sub-Saharan Africa had the highest age-standardised death rate among GBD super-regions for all years of the study period (32.2 [25.8-38.6] deaths per 100 000 population in 2017), and the high-income super-region had the lowest (10.1 [9.8-10-5] deaths per 100 000 population in 2017). The age-standardised death rate decreased or remained constant from 1990 to 2017 in all GBD regions except eastern Europe and central Asia, where the age-standardised death rate increased, primarily due to increases in alcohol-related liver disease prevalence. At the national level, the age-standardised death rate of cirrhosis was lowest in Singapore in 2017 (3.7 [3.3-4.0] per 100 000 in 2017) and highest in Egypt in all years since 1990 (103.3 [64.4-133.4] per 100 000 in 2017). There were 10.6 million (10.3-10.9) prevalent cases of decompensated cirrhosis and 112 million (107-119) prevalent cases of compensated cirrhosis globally in 2017. There was a significant increase in age-standardised prevalence rate of decompensated cirrhosis between 1990 and 2017. Cirrhosis caused by NASH had a steady age-standardised death rate throughout the study period, whereas the other four causes showed declines in age-standardised death rate. The age-standardised prevalence of compensated and decompensated cirrhosis due to NASH increased more than for any other cause of cirrhosis (by 33.2% for compensated cirrhosis and 54.8% for decompensated cirrhosis) over the study period. From 1990 to 2017, the number of prevalent cases snore than doubled for compensated cirrhosis due to NASH and more than tripled for decompensated cirrhosis due to NASH. In 2017, age-standardised death and DALY rates were lower among countries and territories with higher SDI. Interpretation Cirrhosis imposes a substantial health burden on many countries and this burden has increased at the global level since 1990, partly due to population growth and ageing. Although the age-standardised death and DALY rates of cirrhosis decreased from 1990 to 2017, numbers of deaths and DALYs and the proportion of all global deaths due to cirrhosis increased. Despite the availability of effective interventions for the prevention and treatment of hepatitis B and C, they were still the main causes of cirrhosis burden worldwide, particularly in low-income countries. The impact of hepatitis B and C is expected to be attenuated and overtaken by that of NASH in the near future. Cost-effective interventions are required to continue the prevention and treatment of viral hepatitis, and to achieve early diagnosis and prevention of cirrhosis due to alcohol-related liver disease and NASH.
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