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  • 1
    Online Resource
    Online Resource
    Management of Extremity Venous Thrombosis in Neonates and Infants: An Experience From a Resource Challenged Setting
    SAGE Publications ; 2019
    In:  Clinical and Applied Thrombosis/Hemostasis Vol. 25 ( 2019-01-01), p. 107602961881435-
    Details
    In: Clinical and Applied Thrombosis/Hemostasis, SAGE Publications, Vol. 25 ( 2019-01-01), p. 107602961881435-
    Abstract: We aimed to evaluate the outcome of different treatment modalities for extremity venous thrombosis (VT) in neonates and infants, highlighting the current debate on their best tool of management. This retrospective study took place over a 9-year period from January 2009 to December 2017. All treated patients were referred to the vascular and pediatric surgery departments from the neonatal intensive care unit. All patients underwent a thorough history-taking as well as general clinical and local examination of the affected limb. Patients were divided into 2 groups: group I included those who underwent a conservative treated with the sole administration of unfractionated heparin (UFH), whereas group II included those who were treated with UFH plus warfarin. Sixty-three patients were included in this study. They were 36 males and 27 females. Their age ranged from 3 to 302 days. Forty-one (65%) patients had VT in the upper limb, whereas the remaining 22 (35%) had lower extremity VT. The success rate of the nonsurgical treatment was accomplished in 81% of patients. The remaining 19% underwent limb severing, due to established gangrene. The Kaplan-Meier survival method revealed a highly significant increase in both mean and median survival times in those groups treated with heparin and warfarin compared to heparin-only group ( P 〈 .001). Nonoperative treatment with anticoagulation or observation (ie, wait-and-see policy) alone may be an easily applicable, effective, and a safe modality for management of VT in neonates and infants, especially in developing countries with poor or highly challenged resource settings.
    Type of Medium: Online Resource
    ISSN: 1076-0296 , 1938-2723
    URL: Article
    DOI: 10.1177/1076029618814353
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2019
    detail.hit.zdb_id: 2230591-9
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  • 2
    Online Resource
    Online Resource
    Wind-driven permanent magnet synchronous generators connected to a power grid: Existing perspective and future aspects
    SAGE Publications ; 2022
    In:  Wind Engineering Vol. 46, No. 1 ( 2022-02), p. 189-199
    Details
    In: Wind Engineering, SAGE Publications, Vol. 46, No. 1 ( 2022-02), p. 189-199
    Abstract: Scholars are motivated to work in the field of renewable energy systems (RESs) especially on grid-connected wind generators because of the exciting and noticeable developments going on in this area. This progress is utilized to obtain the maximal, efficient, and stable electric power from the RESs and integrating it into existing systems to improve its efficiency, stability, reliability, and overall power quality. Recently, permanent magnet synchronous generators (PMSGs) have become the main pillar of advanced wind systems thanks to their fascinating pluses over other types of wind generators. This paper presents the up-to-date trends in converter topologies, control approaches, maximal power production methods, and grid integration issues for PMSG-based wind systems. The performed statistical analyses assure the dominance of the two-level back-to-back converter among the studied power converter topologies, field-oriented control method for the machine side converter, voltage oriented control method for the grid side converter control, perturb and observe algorithm amongst the studied maximum power point techniques, and fault ride-through capability out of grid integration issues. Further, recent general trends in technological advancements for PMSG wind system components are illustrated as a pie chart in terms of percentage figures. It is expected that the researchers working in this field would benefit from this article in terms of the presented state-of-the-art statistical analyses and its related literature given in this study.
    Type of Medium: Online Resource
    ISSN: 0309-524X , 2048-402X
    URL: Article
    DOI: 10.1177/0309524X211022728
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2022
    detail.hit.zdb_id: 2026065-9
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  • 3
    Online Resource
    Online Resource
    Dynamic evaluation of optimization techniques–based proportional–integral controller for wind-driven permanent magnet synchronous generator
    SAGE Publications ; 2021
    In:  Wind Engineering Vol. 45, No. 3 ( 2021-06), p. 696-709
    Details
    In: Wind Engineering, SAGE Publications, Vol. 45, No. 3 ( 2021-06), p. 696-709
    Abstract: Converters of permanent magnet synchronous generator (PMSG), driven by wind turbines, are controlled by a classical proportional–integral controller. However, many research studies highlighted the challenge in PMSG due to the poor performance of the classical proportional–integral controller, especially in the event of faults or wind speed variations. This article proposes a solution for the limitations of the classical proportional–integral controller with PMSG driven by a wind turbine. The proposed solution includes two optimization techniques: gray wolf optimizer and whale optimizer algorithm. To ensure the effectiveness of the proposed techniques, step change and random variation of wind speed are studied. Moreover, fault ride-through capability of the PMSG is studied with gray wolf optimizer and whale optimizer algorithm techniques during the occurrence of a three-phase fault incident. In this case, a braking chopper controlled by a hysteresis controller is connected to the DC-link capacitor. The simulated results show that compared with the classical proportional–integral controller, gray wolf optimizer and whale optimizer algorithm techniques are greatly efficient in improving the dynamic behavior of the PMSG during wind speed variations. Moreover, gray wolf optimizer and whale optimizer algorithm techniques present their effectiveness during the fault incident by suppressing the transient variations of all the PMSG parameters, improving the fault ride-through capability, and decreasing the total harmonic distortion of the current waveforms. All simulations are performed with MATLAB/ Simulink program package.
    Type of Medium: Online Resource
    ISSN: 0309-524X , 2048-402X
    URL: Article
    DOI: 10.1177/0309524X20930421
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2021
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  • 4
    Online Resource
    Online Resource
    An internal parallel capacitor control strategy for DC-link voltage stabilization of PMSG-based wind turbine under various fault conditions
    SAGE Publications ; 2022
    In:  Wind Engineering Vol. 46, No. 3 ( 2022-06), p. 983-992
    Details
    In: Wind Engineering, SAGE Publications, Vol. 46, No. 3 ( 2022-06), p. 983-992
    Abstract: In recent years, wind energy conversion systems (WECSs) have been growing rapidly. Due to various advantages, a permanent magnet synchronous generator (PMSG) is an appealing solution among different types of wind generators. As wind power penetration level in the grid increases, wind power impacts the grid and vice versa. The most essential concerns in the system are voltage sag and swell, and grid code compliance, particularly for low voltage ride-through (LVRT) and high voltage ride-through (HVRT) capability, is a pressing necessity. This paper presents a parallel capacitor (PC) control strategy to enhance the LVRT and HVRT capability of PMSG. Furthermore, this study presents a method for the sizing of a PC system for the reduction of the overvoltage of the DC-link during voltage sags and swell. Fast Fourier transform analysis is used to determine the total harmonic distortion (THD) for the injected current into the grid. The obtained results illustrate the effectiveness of the proposed system in keeping the DC-link voltage below the limit, power quality improvement, and increasing the LVRT and HVRT capability. Models of wind turbine, PMSG, and PC control system are built using MATLAB/SIMULINK software.
    Type of Medium: Online Resource
    ISSN: 0309-524X , 2048-402X
    URL: Article
    DOI: 10.1177/0309524X211060684
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2022
    detail.hit.zdb_id: 2026065-9
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  • 5
    Online Resource
    Online Resource
    Design and implementation of FLC system for fault ride-through capability enhancement in PMSG-wind systems
    SAGE Publications ; 2021
    In:  Wind Engineering Vol. 45, No. 5 ( 2021-10), p. 1361-1373
    Details
    In: Wind Engineering, SAGE Publications, Vol. 45, No. 5 ( 2021-10), p. 1361-1373
    Abstract: Fault ride-through (FRT) capability enhancement for the growth of renewable energy generators has become a crucial issue for their incorporation into the electricity grid to provide secure, reliable, and efficient electricity. This paper presents a new FRT capability scheme for a permanent magnet synchronous generator (PMSG)-based wind energy generation system using a hybrid solution. The hybrid solution is a combination of a braking chopper (BC) and a fuzzy logic controller (FLC). All proportional-integral (PI) controllers which control the generator and grid side converters are replaced with FLC. Moreover, a BC system is connected to the dc link to improve the dynamic response of the PMSG during fault conditions. The PMSG was evaluated on a three-phase fault that occurs on an electrical network in three scenarios. In the first two scenarios, a BC is used with a PI controller and FLC respectively. While the third scenario uses only FLC without a BC. The obtained results showed that the suggested solution can not only enhance the FRT capability of the PMSG but also can diminish the occurrence of hardware systems and reduce their impact on the PMSG system. The simulation tests are performed using MATLAB/SIMULINK software.
    Type of Medium: Online Resource
    ISSN: 0309-524X , 2048-402X
    URL: Article
    DOI: 10.1177/0309524X20981773
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2021
    detail.hit.zdb_id: 2026065-9
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  • 6
    Online Resource
    Online Resource
    Effect of combined occupational exposure to noise and organic solvents on hearing
    SAGE Publications ; 2012
    In:  Toxicology and Industrial Health Vol. 28, No. 10 ( 2012-11), p. 901-907
    Details
    In: Toxicology and Industrial Health, SAGE Publications, Vol. 28, No. 10 ( 2012-11), p. 901-907
    Abstract: Noise exposure has been commonly regarded as the main hazard of occupational hearing loss. Recent studies indicate that several chemicals, including organic solvents have ototoxic effects. This study aimed at evaluating the hearing of workers exposed to both noise and a mixture of organic solvents at concentrations anticipated as safe. The study comprised three groups. The first one included 70 workers exposed to noise only, the second group consisted of 93 workers exposed to organic solvents and noise, and the control group included 59 individuals exposed to neither noise nor organic solvents. The three groups were matched for age, socioeconomic status, and smoking habit. The results of this study revealed that there was no statistically significant difference between the two exposed groups as regards the duration of exposure. There was a highly statistically significant difference between the two exposed groups as regards the different types of hearing loss (conductive deafness, sensory neural hearing loss, and mixed type) compared with the control one. Our study reported that sensory neural hearing loss occurred earlier in subjects with combined exposure to noise and solvents at a mean duration of exposure (16.38 ± 9.44 years) compared to (24.53 ± 9.59 years) the subjects with sole exposure to noise. The difference between the two groups was statistically significant regarding this type of hearing impairment ( p 〈 0.05). There was a positive significant correlation between hearing impairment and duration of exposure in the two exposed groups. As regards the results of the environmental monitoring, both noise exposure levels (dB) and levels of different organic solvents measured (mg/m 3 ) in different work departments were less than the levels recommended by Egyptian Environmental Law No. 4 for 1994. It is recommended that in the case of combined exposure, noise and solvent levels should be lowered than the permissible limits recommended for either alone.
    Type of Medium: Online Resource
    ISSN: 0748-2337 , 1477-0393
    URL: Article
    DOI: 10.1177/0748233711427051
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2012
    detail.hit.zdb_id: 2010891-6
    SSG: 12
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  • 7
    Online Resource
    Online Resource
    Hypoxia Biomarkers, Oxidative Stress, and Circulating Microparticles in Pediatric Patients With Thalassemia in Upper Egypt
    SAGE Publications ; 2014
    In:  Clinical and Applied Thrombosis/Hemostasis Vol. 20, No. 5 ( 2014-07), p. 536-545
    Details
    In: Clinical and Applied Thrombosis/Hemostasis, SAGE Publications, Vol. 20, No. 5 ( 2014-07), p. 536-545
    Abstract: This study aimed to investigate the oxidative stress, hypoxia biomarkers, and circulating microparticles (MPs) in β thalassemia major. The study included 56 children with thalassemia and 46 healthy controls. Hypoxia biomarkers, oxidative stress biomarkers, and total plasma fragmented DNA (fDNA) were detected by the standard methods. The MPs were assessed by flow cytometry. Hypoxia and oxidative stress biomarkers, fDNA, and MPs were higher and total antioxidant capacity (TAC) was lower in patients with thalassemia than the controls. In splenectomized patients and those who had complications, vascular endothelial growth factor (VEGF), malondialdehyde, fDNA, endothelial, platelet, and activated platelet MP levels were higher while, TAC was lower than the nonsplenectomized patients. In conclusion, the increased tissue hypoxia, oxidative stress in β thalassemia, and its relationship with DNA damage and MPs release could explain many complications of thalassemia and may have therapeutic implications. The VEGF could serve as an important indicator for adequacy of blood transfusion in thalassemia.
    Type of Medium: Online Resource
    ISSN: 1076-0296 , 1938-2723
    URL: Article
    DOI: 10.1177/1076029612472552
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2014
    detail.hit.zdb_id: 2230591-9
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