| 31. |
- Abbas, Muhammad Tahir, et al.
(författare)
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Towards zero-energy : Navigating the future with 6G in Cellular Internet of Things
- 2024
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Ingår i: Journal of Network and Computer Applications. - : Elsevier. - 1084-8045 .- 1095-8592. ; 230
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Tidskriftsartikel (refereegranskat)abstract
- The Cellular Internet of Things (CIoT) has seen significant growth in recent years. With the deployment of 5G, it has become essential to reduce the power consumption of these devices for long-term sustainability. The upcoming 6G cellular network introduces the concept of zero-energy CIoT devices, which do not require batteries or manual charging. This paper focuses on these devices, providing insight into their feasibility and practical implementation. The paper examines how CIoT devices use simultaneous wireless information and power transfer, beamforming, and backscatter communication techniques. It also analyzes the potential use of energy harvesting and power management in zero-energy CIoT devices. Furthermore, the paper explores how low-power transceivers can lower energy usage while maintaining dependable communication functions.
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| 32. |
- Abbas, Shahrukh, et al.
(författare)
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Impact Analysis of Large-Scale Wind Farms Integration in Weak Transmission Grid from Technical Perspectives
- 2020
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Ingår i: Energies. - : MDPI. - 1996-1073. ; 13:20
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Tidskriftsartikel (refereegranskat)abstract
- The integration of commercial onshore large-scale wind farms into a national grid comes with several technical issues that predominately ensure power quality in accordance with respective grid codes. The resulting impacts are complemented with the absorption of larger amounts of reactive power by wind generators. In addition, seasonal variations and inter-farm wake effects further deteriorate the overall system performance and restrict the optimal use of available wind resources. This paper presented an assessment framework to address the power quality issues that have arisen after integrating large-scale wind farms into weak transmission grids, especially considering inter-farm wake effect, seasonal variations, reactive power depletion, and compensation with a variety of voltage-ampere reactive (Var) devices. Herein, we also proposed a recovery of significant active power deficits caused by the wake effect via increasing hub height of wind turbines. For large-scale wind energy penetration, a real case study was considered for three wind farms with a cumulative capacity of 154.4 MW integrated at a Nooriabad Grid in Pakistan to analyze their overall impacts. An actual test system was modeled in MATLAB Simulink for a composite analysis. Simulations were performed for various scenarios to consider wind intermittency, seasonal variations across four seasons, and wake effect. The capacitor banks and various flexible alternating current transmission systems (FACTS) devices were employed for a comparative analysis with and without considering the inter-farm wake effect. The power system parameters along with active and reactive power deficits were considered for comprehensive analysis. Unified power flow controller (UPFC) was found to be the best compensation device through comparative analysis, as it maintained voltage at nearly 1.002 pu, suppressed frequency transient in a range of 49.88-50.17 Hz, and avoided any resonance while maintaining power factors in an allowable range. Moreover, it also enhanced the power handling capability of the power system. The 20 m increase in hub height assisted the recovery of the active power deficit to 48%, which thus minimized the influence of the wake effect.
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| 33. |
- Abbott, Jessica K., et al.
(författare)
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The microevolutionary response to male-limited X-chromosome evolution in Drosophila melanogaster reflects macroevolutionary patterns
- 2020
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Ingår i: Journal of Evolutionary Biology. - : Wiley-Blackwell. - 1010-061X .- 1420-9101. ; 33:6, s. 738-750
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Tidskriftsartikel (refereegranskat)abstract
- Due to its hemizygous inheritance and role in sex determination, the X-chromosome is expected to play an important role in the evolution of sexual dimorphism and to be enriched for sexually antagonistic genetic variation. By forcing the X-chromosome to only be expressed in males over >40 generations, we changed the selection pressures on the X to become similar to those experienced by the Y. This releases the X from any constraints arising from selection in females and should lead to specialization for male fitness, which could occur either via direct effects of X-linked loci or trans-regulation of autosomal loci by the X. We found evidence of masculinization via up-regulation of male-benefit sexually antagonistic genes and down-regulation of X-linked female-benefit genes. Potential artefacts of the experimental evolution protocol are discussed and cannot be wholly discounted, leading to several caveats. Interestingly, we could detect evidence of microevolutionary changes consistent with previously documented macroevolutionary patterns, such as changes in expression consistent with previously established patterns of sexual dimorphism, an increase in the expression of metabolic genes related to mito-nuclear conflict and evidence that dosage compensation effects can be rapidly altered. These results confirm the importance of the X in the evolution of sexual dimorphism and as a source for sexually antagonistic genetic variation and demonstrate that experimental evolution can be a fruitful method for testing theories of sex chromosome evolution.
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| 34. |
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| 35. |
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| 36. |
- Abdel-Rehim, Mohamed
(författare)
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Microextraction by packed sorbent (MEPS) : A tutorial
- 2011
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Ingår i: Analytica Chimica Acta. - : Elsevier BV. - 0003-2670 .- 1873-4324. ; 701:2, s. 119-128
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Tidskriftsartikel (refereegranskat)abstract
- This tutorial provides an overview on a new technique for sample preparation, microextraction by packed sorbent (MEPS). Not only the automation process by MEPS is the advantage but also the much smaller volumes of the samples, solvents and dead volumes in the system. Other significant advantages such as the speed and the simplicity of the sample preparation process are provided. In this tutorial the main concepts of MEPS will be elucidated. Different practical aspects in MEPS are addressed. The factors affecting MEPS performance will be discussed. The application of MEPS in clinical and pre-clinical studies for quantification of drugs and metabolites in blood, plasma and urine will be provided. A comparison between MEPS and other extraction techniques such as SPE, LLE, SPME and SBSE will be discussed. (C) 2011 Elsevier B.V. All rights reserved.
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| 37. |
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| 38. |
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| 39. |
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| 40. |
- Abdel-Rehim, Mohamed, et al.
(författare)
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Microextraction in Packed Syringe Online with Liquid Chromatography-Tandem Mass Spectrometry : Molecularly imprinted polymer as packing material for MEPS in selective extraction of ropivacaine from plasma
- 2006
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Ingår i: Journal of Liquid Chromatography & Related Technologies. - : Informa UK Limited. - 1082-6076 .- 1520-572X. ; 29:12, s. 1725-1736
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Tidskriftsartikel (refereegranskat)abstract
- The excellent performance of a new sample preparation method, microextraction in packed syringe (MEPS), was recently illustrated by online LC‐MS and GS‐MS assays of local anaesthetics in plasma samples. In the method, approximately 1 mg of solid packing material was inserted into a syringe (100–250 µL) as a plug. Sample preparation took place on the packed bed. The new method was easy to use, fully automated, of low cost, and rapid in comparison with previously used methods. This paper presents the use of molecularly imprinted polymers (MIPs) as packing material for higher extraction selectivity. Development and validation of a method for MIP‐MEPS online with LC‐MS‐MS using ropivacaine in plasma as model compound were investigated. A bupivacaine imprinted polymer was used. The method was validated and the standard curves were evaluated by means of quadratic regression and weighted by inverse of the concentration: 1/x for the calibration range 2–2000 nM. The applied polymer could be used more than 100 times before the syringe was discarded. The extraction recovery was 60%. The results showed high correlation coefficients (R 2 >0.999) for all runs. The accuracy, given as a percentage deviation from the nominal concentration values, ranged from -6% to 3%. The precision, given as the relative standard deviation, at three different concentrations (QC samples) was consistently about 3% to 10%. The limit of quantification was 2 nM.
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