68 research outputs found
First person – Meraj Hasan Khan
No full textABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Meraj Hasan Khan is the first author on ‘The Sharpin interactome reveals a role for Sharpin in lamellipodium formation via the Arp2/3 complex’, published in Journal of Cell Science. Meraj is a PhD student in the laboratory of Jeroen Pouwels at the University of Turku, Finland, investigating the cytoskeleton and protein early markers of metastasis.</jats:p
اردو کی ابتدائی نثری تصنیف" معراج العاشقین": تحقیق و تنقید کے آئینے میں
No full textThis research paper is divided into three main sections. The first part introduces the book titled Meraj-ul-Ashiqeen, analyses the subject and content with special emphasis on the terminology of mysticism used by the author. In the second part, excerpts and examples which are often quoted in the books of early history of literature are reproduced so as to enable a serious reader to sample Deccani language and literature; salient features of the prose style of the author are also highlighted and discussed here. In the last section, an attempt has been made to establish Kh. Banda Nawaz as the author of Meraj-ul-Ashiqeen, repudiating the arguments of Dr. Hafeez Qateel
Patient empowerment in dose adjustment of premixed insulin
No full textBackground: To compare the patient-led titration (intervention group) versus physician-led titration (control group) in optimizing the use of premixed insulin in patients with uncontrolled Diabetes treated DM-2.
Methods: This Prospective, Randomized, open-label controlled trial was carried out for 6 months at Endocrinology and Medicine Clinics of Shifa Hospital .Total of 50 patients ,25 in patient-led titration (intervention group) versus 25 in physician-led titration (control group) after written informed consent, fulfilling other inclusion criteria and exclusion criteria were enrolled. Fasting blood sugar were checked on Monday, Tuesday and Wednesday before injecting premixed insulin, average of three readings were calculated , if the average was more than 110mg/dl then 2 units of insulin was increased at night. When the average was between 80- 110mg/dl, night dose remained same and for below 80mg/dl, decreased 2 units of insulin. Simultaneously pre-dinner blood sugar was checked on Thursday, Friday and Saturday to adjust the morning dose. Patients were advised for follow up initially weekly for two weeks then monthly visits for two months. At the beginning and end of study, patient were advised to check fasting,pre-dinner blood sugar and ( PRE / Post HBA1c ) Both groups were provided with a booklet containing basic information about insulin hypoglycemia, injection technique and telephonic access to the clinical team.
Results: The primary efficacy criterion will be the change of HbA1c from baseline to study endpoint. Comparative analysis between the two groups PRE / Post HBA1c will be analysed by paired T-test. Significance of p value will be less than 0.05.
Conclusions: SMBG is an important self-management tool for insulin-treated patients with DM-2. With SMBG & guidance, patients can adjust their insulin dose quickly to achieve the good glycemic control Keywords: Self-monitoring of blood glucose glycated Heamoglobin (HBA1c ). DM-
Interleaved Multilevel Boost Converter With Minimal Voltage Multiplier Components for High-Voltage Step-Up Applications
No full textIn this article, a new interleaved multilevel boost converter (interleaved-MBC) is suggested with minimal voltage multiplier (VM) cells for high-voltage step-up applications. The interleaved-MBC is derived in such a way that the maximum utilization of the VM circuit operation can be achieved by the interleaved structure. Furthermore, compared to existing multilevel interleaved converters, the reduced number of capacitors and diode with equal voltage rating makes it more attractive. Similar to the existing multilevel converter, the feature of the interleaved-MBC provides the extension of the number of levels to achieve the necessary voltages just by adding similar capacitor-diode stages (single capacitor and single diode are required to increase the stage by one). The features like continuous input current, low-input ripples, high voltage conversion ratio, and reduced stress on devices make the proposed converter more suitable for the voltage step-up applications, such as dc link, hybrid distribution systems, hybrid photovoltaic systems, etc. The detailed analysis of the converter is carried out by considering the nonidealities in the power circuit. The operation of the interleaved-MBC is presented for continuous and discontinuous conduction modes with boundary conditions. The components selection criterion and the comparison of converters are presented with suitable discussions. The converter is experimentally tested, and the obtained results validate its performance and functionality.Manuscript received October 5, 2019; revised January 11, 2020 and March 20, 2020; accepted April 20, 2020. Date of publication May 5, 2020; date of current version July 31, 2020. This work was supported in part by the Qatar National Library, Doha, Qatar, and in part by the Qatar National Research Fund, Qatar Foundation, under NPRP Grant X-033-2-007. Recommended for publication by Associate Editor Y. Siwakoti. (Corresponding author: Atif Iqbal.) Mohammad Meraj, Atif Iqbal, and Nasser Al-Emadi are with the Department of Electrical Engineering Qatar University, Doha, Qatar (e-mail: Meraj@ qu.edu.qa; [email protected]; [email protected]).Scopu
Development and validation of a tool for assessing professionalism among Pakistani medical students
No full textData sets of study submitted at MedED Publis
Nonisolated Symmetrical Interleaved Multilevel Boost Converter with Reduction in Voltage Rating of Capacitors for High-Voltage Microgrid Applications
No full textThis article proposed a nonisolated symmetrical interleaved multilevel boost converter for high-voltage microgrid applications. The proposed converter configuration is derived from the integration of a voltage multiplier (VM) circuit with the front-end structure of the classical two-phase interleaved converter. Moreover, equal voltage rating capacitors and diodes are suitable to design multiple stages of the proposed converter. The proposed converter can feed from two independent sources or single source in the interleaved approach. The continuous input current, high-voltage gain, reduced voltage rating of capacitor (that causes reduction in cost), reduced components, and flexibility in number of sources make the proposed converter more attractive for renewable dc-microgrid applications such as, photovoltaic (PV) system, fuel cell (FC) system, and hybrid PV-FC system. Furthermore, the voltage gain of the converter can be increased by just adding similar stages of VM without preferring the high-voltage rating capacitors and without disturbing the front-end structure of the converter. Nonidealities are considered to analyze the proposed converter in a more practical way. The characteristics and operation of the proposed converter are discussed in this article with the continuous conduction mode and Discontinuous Conduction Mode boundary conditions. The design of the reactive components and selection of semiconductor devices are discussed. Additionally, the proposed converter is compared with recently proposed DC-DC multilevel converters. To support the proposed work, simulation and experimental results are provided which shows a good agreement with the analytical approach. - 1972-2012 IEEE.Manuscript received December 18, 2018; revised April 16, 2019; accepted August 1, 2019. Date of publication August 18, 2019; date of current version November 7, 2019. Paper 2018-HPC-1322.R1, and approved for publication in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS by the High Performance Power Electronic Converters: Topologies, Control, and Devices of the IEEE Industry Applications Society. This work was supported by the NPRP grant X-033-2-007 from the Qatar National Research Fund (a member of Qatar Foundation). (Corresponding author: Atif Iqbal.) M. S. Bhaskar, M. Meraj, and A. Iqbal are with the Department of Electric Engineering, Qatar University, Doha 2713, Qatar (e-mail: sagar25. [email protected]; [email protected]; [email protected]).Scopu
A New Triple-Switch-Triple-Mode High Step-Up Converter with Wide Range of Duty Cycle for DC Microgrid Applications
No full textDC microgrid is gaining attraction and a recent trend in distribution power generation system due to penetration of renewables (especially photovoltaic or fuel cell). In this paper, a new triple-switch-triple-mode high step-up converter (TSTM-HS converter) is presented for dc microgrid applications. In the proposed converter, voltage lift technique is employed and range of duty cycle is extended by incorporating an additional switch in converter circuitry. By doing this, high voltage conversion ratio is achieved without using a transformer, coupled inductor, and multiple stages of switched capacitors. Moreover, the TSTM-HS converter operated in three modes with two types of the duty cycles to achieve low to high voltage conversion without using high duty cycle for each switch. The effects of difference in the inductance values on the regulation and operating behavior of the TSTM-HS converter are discussed. The continuous conduction mode and discontinuous conduction mode characteristics of the TSTM-HS converter are discussed in detail with steady-state analysis and boundary condition. The comparison is provided to highlight the benefits of the TSTM-HS converter. The selection of semiconductor devices and the design of reactive components are discussed for the TSTM-HS converter. The experimental results of the proposed converter are provided which validate the theoretical approach, performance, and feasibility of converter. - 1972-2012 IEEE.Manuscript received December 19, 2018; revised April 5, 2019; accepted May 21, 2019. Date of publication June 2, 2019; date of current version November 7, 2019. Paper 2018-HPC-1346.R1, approved for publication in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS of the IEEE Industry Applications Society. This work was supported by NPRP under Grant X-033-2-007 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. (Corresponding author: Atif Iqbal.) M. S. Bhaskar, R. Alammari, M. Meraj, and A. Iqbal are with the Department of Electrical Engineering, Qatar University, Doha 2713, Qatar (e-mail: [email protected]; [email protected]; meraj@qu. edu.qa; [email protected]).Scopu
A Novel Modified Switched Inductor Boost Converter with Reduced Switch Voltage Stress
No full textRecently, switched inductor (SI) and switched capacitor techniques in dc-dc converter are recommended to achieve high voltage by using the principle of parallel charging and series discharging of reactive elements. It is noteworthy that four diodes, one high-voltage rating switch, and two inductors are required to design classical SI boost converter (SIBC). Moreover, in classical SIBC, the switch voltage stress is equal to the output voltage. In this article, modified SIBC (mSIBC) is proposed with reduced voltage stress across active switches. The proposed mSIBC configuration in this article is transformerless and simply derived by replacing the one diode of the classical SI structure with an active switch. As a result, mSIBC required low-voltage rating active switches, since the total output voltage is shared into two active switches. Moreover, the proposed mSIBC is low in cost, provides higher efficiency, and requires the same number of components compared with the classical SIBC. The continuous conduction mode and discontinuous conduction mode analysis, the effect of nonidealities on voltage gain, design methodology, and comparison are presented in detail. The operation and performance of the designed 500-W mSIBC are experimentally validated under different perturbations.Manuscript received July 14, 2019; revised October 15, 2019 and December 13, 2019; accepted January 3, 2020. Date of publication February 5, 2020; date of current version October 30, 2020. This work was supported by Qatar University High Impact under Grant QUHI-CENG-19/20-2, from the Qatar University. The publication charges are funded by the Qatar National Library. The statements made herein are solely the responsibility of the authors. (Corresponding author: Atif Iqbal.) S. Sadaf, M. Meraj, A. Iqbal, and N. Al-Emadi are with the Department of Electrical Engineering, Qatar University, Doha 2713, Qatar (e-mail: [email protected]; [email protected]; [email protected]; [email protected]).Scopu
A New Variable Frequency Control of 49-Level Cascaded Packed U-Cell Voltage Source Inverter
No full textRequirement of large number of levels with lower number of switching devices has made asymmetrical converters more popular than the symmetrical ones. Asymmetrical cascaded multilevel inverters (ACMLI) can achieve high efficiency by combining switching devices with different voltage ratings and technologies. The proposed ACMLI cascades two or more units of packed U-Cell (PUC) inverters using two or more isolated dc link supplies. In this article, one of the PUC unit is controlled using high switching frequency while the other PUCs are operated in a step mode at low switching frequencies, thus operating them in a variable frequency control mode. The cascading of two 7-level PUC inverters with dc link voltage ratio of 1:7 can produce an output voltage with 49 (7x7) levels. The multilevel output voltage waveform is nearly sinusoidal with very low THD content, and the low switching frequency operation leads to lower power dissipation and greater system efficiency. However, each PUC module requires two dc voltage sources. To address this concern, in this article, each PUC module consists of one dc voltage source and one dc bus capacitor. With the cascaded PUC topology and proposed control algorithm, load current and dc bus capacitor voltage control is achieved simultaneously. The proposed converter and its control technique lead to the breaking of the design tradeoff rule between switching frequency (efficiency) and filter size. This is very useful in various applications such as uninterruptible power supplies and grid-tie inverters. The converter and its control technique are simulated using MATLAB/Simulink software and simulation results for both open loop and closed loop are discussed. Hardware results are obtained by developing a 1-kW experimental prototype. Simulation and experimental results confirm the usefulness and effectiveness of the proposed topology and its control technique. - 1972-2012 IEEE.Manuscript received January 24, 2019; revised June 20, 2019; accepted August 11, 2019. Date of publication September 11, 2019; date of current version November 7, 2019. Paper 2018-HPC-1401.R1, approved for publication in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS by the High Performance Power Electronic Converters: Topologies, Control, and Devices Committee of the IEEE Industry Applications Society. This work was supported by NPRP-EP Grant # [X-033-2-007] from the Qatar National Research Fund (a member of Qatar Foundation). (Corresponding author: Mohd Tariq.) M. Meraj, S. Rahman, A. Iqbal, and L. Ben-Brahim are with the Department of Electrical Engineering, Qatar University, Doha 2713, Qatar (e-mail: [email protected]; [email protected]; [email protected]; brahim@ qu.edu.qa).Scopu
Design and Implementation of Cascaded Multilevel qZSI Powered Single-Phase Induction Motor for Isolated Grid Water Pump Application
No full textThis article presents the design and implementation of solar-powered V/f controlled single-phase capacitor-start induction motor. Multilevel quasi impedance source inverter controls the power flowing from the photovoltaic (PV) array to a single-phase induction motor. In solar powered drive systems, the main concern is stable intended operation of drive when subjected to variations in power generation of the PV array. For same environmental conditions, the PV power extraction is different at different torques for constant speed application. Due to this, the extraction of maximum power with an MPPT algorithm is not achieved with only motor load. To address this concern, concept of the battery storage system is introduced in the system that helps in achieving maximum power when the PV power generation capability exceeds rated motor input power. In addition to this, battery storage system can supply power to the load when the PV power generation is less than the rated motor input power. Conclusively, the design of control algorithm must address issues of the MPPT algorithm, control of battery storage system, and stable operation of V/f-controlled induction motor drive operation. MATLAB/Simulink model of the proposed system with 4 kW PV array rating is developed. The proposed control algorithm achieves satisfactory operation of single-phase motor drive in all the three operation modes (depending upon PV power generation). The variation of the solar irradiation and temperature are simultaneously considered for introducing perturbation in the PV power generation. Hardware results for this system are also presented, which validates the effectiveness of the control algorithm for the proposed system.Manuscript received July 20, 2018; revised October 29, 2018; accepted December 12, 2018. Date of publication December 15, 2019; date of current version March 17, 2020. Paper 2018-IACC-0679.R1, presented at the 2017 IEEE Energy Conversion Congress and Exposition, Cincinnati, OH, USA, Oct. 1-5, and approved for publication in the IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS by the Industrial Automation and Control Committee of the IEEE Industry Applications Society. This work was supported by the National Priorities Research Program�-Exceptional Proposals through Qatar National Research Fund (a member of Qatar Foundation) under Grant X-033-2-007. (Corresponding author: Mohd Tariq.) S. Rahman, M. Meraj, A. Iqbal, L. Ben-Brahim, and R. Al-ammari are with the Department of Electrical Engineering, Qatar University, Doha, Qatar (e-mail: [email protected]; [email protected]; [email protected]; [email protected]; [email protected]).Scopu
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