Improved Current Controlled Doubly Fed Induction Generator Model with Grid Integration Under Sub and Super Synchronous Conditions

Arslan Ahmed Amin,Hamza Ahmad,Hassan Khalid,Neha Masroor,Huda Mahmood,Muhammad Abubakar 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.1

This paper presents the development and experimental verifi cation of the mathematical model of wind turbine and Doubly Fed Induction Generator (DFIG) using the current control and voltage estimation method between the DC link. The rotor of the induction generator (IG) is rotated with the wind turbine at a specifi c speed. The DFIG is directly coupled with a grid station and the synchronization between DFIG and the grid station is controlled by setting two converters: Machine Side Converter (MSC) implemented with the rotor side and Grid Side Converter (GSC) implemented with the grid. PI controllers have been utilized in the control loops and the parametric range is extracted to maximize the mechanical power transferred to the IG rotor. The model is tested under three conditions DFIG running at super synchronous speed, synchronous speed, and under synchronous speed using MATLAB Simulink. In the end, the same model is also tested through a series of experiments using lab modules. The results show that the proposed model is much simplifi ed and accurate as compared to previous versions available in the literature.

Foreign Capital Inflows and Stock Market Development in Pakistan

Ali SAJID,Muhammad Arsalan HASHMI,A,ABDULLAH,Muhammad Amin HASSAN 한국유통과학회 2021 The Journal of Asian Finance, Economics and Busine Vol.8 No.6

The study examines how foreign capital inflows affect stock market development in Pakistan for the period from July 2008 to June 2018. Several components of foreign capital inflows were used for empirical analysis, namely, foreign direct investment, foreign portfolio investment, and remittances. Further, market capitalization was used as a proxy for stock market development. The study uses an ARDL model for examining the long-run and short-run relationships between variables. We also analyze the bi-directional causality between the variables through the Granger causality test. Further, the presence of structural breaks was analyzed through the CUSUM and CUSUM Square test. The results suggest that in the long run, remittances have a positive and significant relationship with stock market development. However, foreign direct investment, foreign portfolio investment, and USD-PKR exchange rate do not have a significant impact on stock market development. The results also suggest that in the short run there is a negative relationship between FDI, USD-PKR exchange rate and market capitalization. Contrarily, we found a positive relationship between FPI and market capitalization. The results of Granger causality test suggest that remittances and USD-PKR exchange rate have a causal relationship with stock market development. Finally, we found no evidence of structural breaks in the dataset.

Diversity in Betasatellites Associated with Cotton Leaf Curl Disease During Source-To-Sink Movement Through a Resistant Host

Iftikhar Ali Khan,Khalid Pervaiz Akhtar,Fazal Akbar,Ishtiaq Hassan,Imran Amin,Muhammad Saeed,Shahid Mansoor 한국식물병리학회 2016 Plant Pathology Journal Vol.32 No.1

Cotton leaf curl is devastating disease of cotton characterized by leaf curling, vein darkening and enations. The disease symptoms are induced by DNA satellite known as Cotton leaf curl Multan betasatellite (CLCuMuB), dominant betasatellite in cotton but another betasatellite known as Chili leaf curl betasatellite (ChLCB) is also found associated with the disease. Grafting experiment was performed to determine if host plant resistance is determinant of dominant population of betasatellite in cotton (several distinct strains of CLCuMuB are associated with the disease). Infected scion of Gossypium hirsutum collected from field (the source) was grafted on G. arboreum, a diploid cotton species, resistant to the disease. A healthy scion of G. hirsutum (sink) was grafted at the top of G. arboreum to determine the movement of virus/betasatellite to upper susceptible scion of G. hirsutum. Symptoms of disease appeared in the upper scion and presence of virus/betasatellite in the upper scion was confirmed via molecular techniques, showing that virus/betasatellite was able to move to upper scion through resistant G. arboreum. However, no symptoms appeared on G. arboreum. Betasatelites were cloned and sequenced from lower scion, upper scion and G. arboreum which show that the lower scion contained both CLCuMuB and ChLCB, however only ChLCB was found in G. arboreum. The upper scion contained CLCuMuB with a deletion of 78 nucleotides (nt) in the non-coding region between Arich sequence and βC1 gene and insertion of 27 nt in the middle of βC1 ORF. This study may help in investigating molecular basis of resistance in G. arboreum.

Diversity in Betasatellites Associated with Cotton Leaf Curl Disease During Source-To-Sink Movement Through a Resistant Host

Khan, Iftikhar Ali,Akhtar, Khalid Pervaiz,Akbar, Fazal,Hassan, Ishtiaq,Amin, Imran,Saeed, Muhammad,Mansoor, Shahid The Korean Society of Plant Pathology 2016 Plant Pathology Journal Vol.32 No.1

Cotton leaf curl is devastating disease of cotton characterized by leaf curling, vein darkening and enations. The disease symptoms are induced by DNA satellite known as Cotton leaf curl Multan betasatellite (CLCuMuB), dominant betasatellite in cotton but another betasatellite known as Chili leaf curl betasatellite (ChLCB) is also found associated with the disease. Grafting experiment was performed to determine if host plant resistance is determinant of dominant population of betasatellite in cotton (several distinct strains of CLCuMuB are associated with the disease). Infected scion of Gossypium hirsutum collected from field (the source) was grafted on G. arboreum, a diploid cotton species, resistant to the disease. A healthy scion of G. hirsutum (sink) was grafted at the top of G. arboreum to determine the movement of virus/betasatellite to upper susceptible scion of G. hirsutum. Symptoms of disease appeared in the upper scion and presence of virus/betasatellite in the upper scion was confirmed via molecular techniques, showing that virus/betasatellite was able to move to upper scion through resistant G. arboreum. However, no symptoms appeared on G. arboreum. Betasatelites were cloned and sequenced from lower scion, upper scion and G. arboreum which show that the lower scion contained both CLCuMuB and ChLCB, however only ChLCB was found in G. arboreum. The upper scion contained CLCuMuB with a deletion of 78 nucleotides (nt) in the non-coding region between Arich sequence and ${\beta}C1$ gene and insertion of 27 nt in the middle of ${\beta}C1$ ORF. This study may help in investigating molecular basis of resistance in G. arboreum.

Analysis of Hereditary Nonpolyposis Colorectal Cancer in Malay Cohorts using Immunohistochemical Screening

Juhari, Wan Khairunnisa Wan,Rahman, Wan Faiziah Wan Abdul,Sidek, Ahmad Shanwani Mohd,Hassan, Muhammad Radzi Abu,Noordin, Khairul Bariah Ahmad Amin,Zakaria, Andee Dzulkarnaen,Macrae, Finlay,Zilfalil, B Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.9

Background: Lynch syndrome (LS) is an inherited predisposition to colorectal, endometrial (uterine) and other cancers. Although most cancers are not inherited, about 5 percent (%) of people who have colorectal or endometrial cancer have the Lynch syndrome. It involves the alteration of mismatch repair (MMR) genes; MLH1, MSH2, MSH6 or PMS2. In this study, we analyzed the expression of MMR proteins in colorectal cancer in a Malay cohort by immunohistochemistry. Materials and Methods: A total of 17 patients were selected fulfilling one of the Bethesda criteria: colorectal cancer diagnosed in a patient aged less than 50 years old, having synchronous and metachronous colorectal cancer or with a strong family history. Immunohistochemical staining was performed on paraffin embedded tumour tissue samples using four antibodies: MLH1, MSH2, MSH6 and PMS2. Results: Twelve out of 17 patients (70.6%) were noted to have a family history. A total of 41% (n=7) of the patients had abnormal immunohistochemical staining with one or more of the four antibodies. Loss of expression were noted in 13 tumour tissues with a negative staining score <4. Of 13 tumour tissues, four showed loss expression of MLH1. For PMS2, loss of expression were noted in five cases. Both MSH2 and MSH6 showed loss of expression in two tumour tissues respectively. Conclusions: Revised Bethesda criteria and immunohistochemical analysis constituted a convenient approach and is recommended to be a first-line screening for Lynch syndrome in Malay cohorts.