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  • 1
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    Online Resource
    Experimental and analytical study of the elliptical vibration-assisted turning process with the dynamic friction model
    SAGE Publications ; 2014
    In:  Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture Vol. 228, No. 6 ( 2014-06), p. 837-846
    Details
    In: Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, SAGE Publications, Vol. 228, No. 6 ( 2014-06), p. 837-846
    Abstract: A novel analytical model for prediction of forces in elliptical vibration-assisted turning using a dynamic friction model is presented in this article and verified with experimental elliptical vibration-assisted turning tests. In elliptical vibration-assisted turning process, the main cause of force reduction is the reversal of the friction force direction in a fraction of vibration cycle time. In analytical modeling of elliptical vibration-assisted turning, the change of the relative sliding velocity direction causes a stick–slip condition which cannot be detected with static friction models like Coulomb model. In this research, a dynamic friction model, named LuGre model, is used to predict the machining forces in elliptical vibration-assisted turning. To derive the model coefficients, a series of orthogonal cutting experiments are performed on Al 6061, Al 7075 T6, Copper and Inconel 718, and the friction coefficients are identified using genetic algorithm optimization method. The cutting forces are determined by incorporating the friction forces calculated from LuGre model. To verify the results, a series of elliptical vibration-assisted turning experiments are performed on four above-mentioned workpiece materials using an elliptical vibration-assisted turning tool. The machining forces are then compared with the analytical results. The results achieved from the analytical solution using LuGre dynamic friction model are in a good agreement with experimental results.
    Type of Medium: Online Resource
    ISSN: 0954-4054 , 2041-2975
    URL: Article
    DOI: 10.1177/0954405413508943
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2014
    detail.hit.zdb_id: 2032745-6
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  • 2
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    Online Resource
    Ab Initio Study of Conformational Properties of ( Z,Z,Z )-Cyclonona-1,3,6-Triene
    SAGE Publications ; 2003
    In:  Journal of Chemical Research Vol. 2003, No. 9 ( 2003-09), p. 546-548
    Details
    In: Journal of Chemical Research, SAGE Publications, Vol. 2003, No. 9 ( 2003-09), p. 546-548
    Abstract: Ab initio molecular orbital and density functional theory (DFT) calculations, applied to ( Z,Z,Z)-cyclonona-1,3,6-triene (1) have revealed that the calculated energy barrier for ring inversion of the twist-boat ( C 1 symmetry) conformation of 1 as a most stable form is 8.41 kcal mol −1 , as calculated by the MP2/6-31G*//HF/6-31G* method
    Type of Medium: Online Resource
    ISSN: 1747-5198 , 2047-6507
    URL: Article
    DOI: 10.3184/030823403322597252
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2003
    detail.hit.zdb_id: 3010810-X
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  • 3
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    Online Resource
    Changes in Small Dense Low-Density Lipoprotein Levels Following Acute Coronary Syndrome
    SAGE Publications ; 2013
    In:  Angiology Vol. 64, No. 3 ( 2013-04), p. 216-222
    Details
    In: Angiology, SAGE Publications, Vol. 64, No. 3 ( 2013-04), p. 216-222
    Abstract: Low-density lipoprotein (LDL), especially small dense LDL (sdLDL), plays a role in atherogenesis. We compared baseline sdLDL levels between healthy controls and patients with acute coronary syndrome (ACS). Blood samples were taken from patients diagnosed with myocardial infarction ([MI] n = 104) and unstable angina ([UA] n = 100). Both sdLDL and high-sensitivity C-reactive protein (hsCRP) levels were determined on admission and in the next 24 hours after the onset of symptoms. Baseline concentration of sdLDL was significantly higher in patients presenting with ACS than controls ( P  〈  .05). In the 24 hours following ACS, the sdLDL levels decreased insignificantly in both groups of patients with ACS ( P  〉  .05). The changes in sdLDL values were not significantly different between MI and UA participants ( P  〉  .05). Patients with ACS have higher concentration of sdLDL compared with the controls.
    Type of Medium: Online Resource
    ISSN: 0003-3197 , 1940-1574
    URL: Article
    DOI: 10.1177/0003319712441855
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2013
    detail.hit.zdb_id: 2065911-8
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  • 4
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    Online Resource
    Development of Online Technique for International Validation of the AO Spine Subaxial Injury Classification System
    SAGE Publications ; 2022
    In:  Global Spine Journal
    Details
    In: Global Spine Journal, SAGE Publications
    Abstract: Global cross-sectional survey Objective To develop and refine the techniques for web-based international validation of fracture classification systems. Methods A live webinar was organized in 2018 for validation of the AO Spine Subaxial Injury Classification System, consisting of 35 unique computed tomography (CT) scans and key images with subaxial spine injuries. Interobserver reliability and intraobserver reproducibility was calculated for injury morphology, subtype, and facet injury according to the classification system. Based on the experiences from this webinar and incorporating rater feedback, adjustments were made in the organization and techniques used and in 2020 a repeat validation webinar was performed, evaluating images of 41 unique subaxial spine injuries. Results In the 2018 session, the AO Spine Subaxial Injury Classification System demonstrated fair interobserver reliability for fracture subtype (κ = 0.35) and moderate reliability for fracture morphology and facet injury (κ=0.45, 0.43, respectively). However, in 2020, the interobserver reliability for fracture morphology (κ = 0.87) and fracture subtype (κ = 0.80) was excellent, while facet injury was substantial (κ = 0.74). Intraobserver reproducibility for injury morphology (κ =0.49) and injury subtype/facet injury were moderate (κ = 0.42) in 2018. In 2020, fracture morphology and subtype reproducibility were excellent (κ =0.85, 0.88, respectively) while reproducibility for facet injuries was substantial (κ = 0.76). Conclusion With optimized webinar-based validation techniques, the AO Spine Subaxial Injury Classification System demonstrated vast improvements in intraobserver reproducibility and interobserver reliability. Stringent fracture classification methodology is integral in obtaining accurate classification results.
    Type of Medium: Online Resource
    ISSN: 2192-5682 , 2192-5690
    URL: Article
    DOI: 10.1177/21925682221098967
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2022
    detail.hit.zdb_id: 2648287-3
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  • 5
    Online Resource
    Online Resource
    Ab Initio Study of Geminal Steric Hindrance Effects on the Stability of Conformations of Cyclohexane Derivatives
    SAGE Publications ; 2005
    In:  Journal of Chemical Research Vol. 2005, No. 8 ( 2005-08), p. 508-515
    Details
    In: Journal of Chemical Research, SAGE Publications, Vol. 2005, No. 8 ( 2005-08), p. 508-515
    Abstract: Ab initio and density functional theory methods (HF/3-21G*//HF/3-21G*, MP2/3-21G*//HF/3-21G*, B3LYP/3-21G*//HF/3-21G*, B3LYP/LANL2DZ*//HF/LANL2DZ*, MP2/LANL2DZ*//HF/LANL2DZ* and HF/LANL2DZ*//HF/LANL2DZ*) used to investigate the conformational properties of cyclohexane, 1,1-dimethylcyclohexane, 1,1-di-tert-butylcyclohexane, 1,1-bis(trimethylsilanyl)cyclohexane, 1,1-bis(trimethylgermanyl)cyclohexane and 1,1-bis(trimethylstannyl)cyclohex ane showed that the energy difference between the chair and twist-boat conformations and also the ring flipping energy barrier decreases from cyclohexane, 1,1-dimethylcyclohexane to 1,1-di-tert-butylcyclohexane, and increases from 1,1-bis(trimethylsilanyl)cyclohexane, 1,1-bis(trimethylgermanyl)cyclohexane to 1,1-bis(trimethylstannyl)cyclohexane.
    Type of Medium: Online Resource
    ISSN: 1747-5198 , 2047-6507
    URL: Article
    DOI: 10.3184/030823405774663219
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2005
    detail.hit.zdb_id: 3010810-X
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  • 6
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    Online Resource
    More Benign Lymphoproliferative Disease after Liver Transplant in Infants
    SAGE Publications ; 2013
    In:  Progress in Transplantation Vol. 23, No. 2 ( 2013-06), p. 158-164
    Details
    In: Progress in Transplantation, SAGE Publications, Vol. 23, No. 2 ( 2013-06), p. 158-164
    Abstract: Despite the high frequency of liver transplants in infants, few data are available on the characteristics of posttransplant lymphoproliferative disorders in liver transplant patients (PTLD). Objective To analyze special features and behavior of PTLD arising after liver transplant in infants. Methods A comprehensive search of the literature was conducted for the available data on PTLD in infant liver transplant recipients through PubMed and Google scholar. An infant was defined as a liver recipient who was less than 2 years old at the time of transplant. Overall, 205 cases of PTLD were found in 24 reports, and the 100 infants with PTLD were compared with children and adults with PTLD. Results PTLD lesions in infants were more likely to be polymorphic whereas monomorphic lesions were more prevalent among older patients ( P= .05). Remission rates, metastasis frequency, and organ involvement did not differ significantly between the groups. Survival analysis showed that the infants had a significantly better outcome than did older patients ( P = .05). Conclusion PTLD is more benign and may have a better outcome in infant liver transplant recipients than in older recipients. A prospective multicenter approach is needed for future research studies.
    Type of Medium: Online Resource
    ISSN: 1526-9248 , 2164-6708
    URL: Article
    DOI: 10.7182/pit2013425
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2013
    detail.hit.zdb_id: 2864264-8
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  • 7
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    Online Resource
    A comparative study of limit diagram of ultrasonic-assisted and conventional hot incremental forming of Ti-6AL-4V alloy
    SAGE Publications ; 2023
    In:  Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering
    Details
    In: Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering, SAGE Publications
    Abstract: Electric hot incremental forming (EHIF) technique is a novel sheet metal forming method for low-formability materials like Mg and Ti-6Al-4V alloys. There are some defects in EHIF including low surface quality, unexpected sheet tear, and oxidation of the fabricated workpieces. These defects limit its widespread use. In this article, longitudinal ultrasonic vibrations of forming tools are used for Ti-6Al-4V sheets in the EHIF process. This technique led to a significant reduction of friction coefficient and improvement of workpieces’ surface quality. Also, a combination of mechanical vibrations and heat reduced the phase transformation temperature of α phase (HCP structure) to the more formable β phase (BBC structure) at 600 °C. It improved Ti-6Al-4V sheets’ formability. In this study, various tensile and compressive strains were created by manufacturing different geometries such as cone, frustum, torispherical, and five-lobe. These strains are used to compare the forming limit diagram of the ultrasonic-assisted and conventional hot incremental forming. The design of the experiment and analysis of variance were employed to identify the optimum condition for creating the largest strains. Also, effective parameters were optimized by response surface methodology. Then major and minor strains for both techniques were compared. Achieved strains in all types of geometries for ultrasonic-assisted technique were higher than those achieved by a conventional process.
    Type of Medium: Online Resource
    ISSN: 0954-4089 , 2041-3009
    URL: Article
    DOI: 10.1177/09544089231189657
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2023
    detail.hit.zdb_id: 2024897-0
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