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High-Performance Elevator Traction Using Direct Torque Controlled Induction Motor Drive
Arafa, Osama Mohamed,Abdallah, Mohamed Elsayed,Aziz, Ghada Ahmed Abdel The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.3
This paper presents a detailed realization of direct torque controlled induction motor drive for elevator applications. The drive is controlled according to the well-known space vector modulated direct control scheme (SVM-DTC). As the elevator drives are usually equipped with speed sensors, flux estimation is carried out using a current model where two stator currents are measured and accurate instantaneous rotor speed measurement is used to overcome the need for measuring stator voltages. Speed profiling for a comfortable elevator ride and other supervisory control activities to provide smooth operation are also explained. The drive performance is examined and controllers' parameters are fine-tuned using MATLAB/SIMULINK. The blocks used for flux and torque estimation and control in the offline simulation are compiled for real-time using dSPACE Microlabox. The performance of the drive has been verified experimentally. The results show good performance under transient and steady state conditions.
Colorectal Cancer in the Arab World - Screening Practices and Future Prospects
Arafa, Mostafa A,Farhat, Karim Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.17
Colorectal cancer (CRC) incidence and mortality rates have dropped 30% in the US in the last 10 years among adults ages 50 and older due to the widespread uptake of colonoscopy, yet incidences in the Arab countries have been increasing in the past ten years, albeit with lower figures when compared with developed countries. Lifestyle changes, food consumption patterns and obesity have been observed during the past years where the regular consumption of traditional foods is being replaced with more Western-style and ready-made foods. Most high income countries have implemented population based colorectal cancer screening programs, which aid in decreasing the incidence and mortality of cancer, while these are lacking in most of the Arab world countries due to many cultural and religious barriers to CRC screening as well as lack of high education or familiarity. What is needed is health education to modify risky lifestyle, and to increase motives and enhance positive attitudes towards early screening especially amongst high risk groups in addition to policy designed to encourage healthier living.
Arafa, Mostafa A.,Rabah, Danny M.,Wahdan, Iman H. Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.9
The current study aimed at exploring the knowledge and beliefs of men aged forty years and over towards prostate cancer screening and early detection in three Arab countries. The field work was conducted in three countries; Saudi Arabia, Egypt and Jordan, during the period February through December 2011. Our target population were men aged 40 years and over. It was a population-based cross sectional study comprising 400 subjects at each site. In addition to socio-demographic data, history of the present and past medical illness, practice history of prostatic cancer examination, family history of cancer prostate; participants were inquired about their knowledge and attitude towards prostate cancer and screening behavior using two different likert scales. The percentage of participants who practiced regular prostate check up ranged from 8-30%. They had poor knowledge and fair attitude towards prostate cancer screening behavior, where the mean total knowledge score was $10.25{\pm}2.5$, $10.76{\pm}3.39$ and $11.24{\pm}3.39$ whereas the mean total attitude score was $18.3{\pm}4.08$, $20.68{\pm}6.4$ and $17.96{\pm}5.3$ for Saudi Arabia, Egypt and Jordan respectively. The respondents identified the physicians as the main sources of this information (62.4%), though they were not the main motives for regular checkup. Knowledge was the only significant predictor for participants' attitude in the multiple regression models. Participants' attitudes depends mainly on level of knowledge and quantity of information provided to the patients and their families. Such attitudes should rely on a solid background of proper information and motivation from physicians to enhance and empower behaviors towards prostate cancer screening practices.
Modifiable Risk Factors for Cardiovascular Disease in Korea and Japan
Ahmed Arafa,Hyeok-Hee Lee,Ehab S. Eshak,Kokoro Shirai,Keyang Liu,Jiaqi Li,Naharin Sultana Anni,Sun Young Shim,Hyeon Chang Kim,Hiroyasu Iso 대한심장학회 2021 Korean Circulation Journal Vol.51 No.8
Cardiovascular disease (CVD) is the leading cause of death and a major contributor to disability worldwide. Since the majority of cardiovascular events are preventable, identification of modifiable CVD risk factors and implementation of primordial prevention strategies should be a public health priority. In this aspect, the American Heart Association declared a strategic goal to reduce total CVD mortality in the US by 20% within 10 years via eliminating 7 major CVD risk factors (hypertension, diabetes, dyslipidemia, cigarette smoking, physical inactivity, obesity, and poor-quality diet) in 2010, and their strategy has been achieving. However, the applicability of similar metrics to prevent CVD among East Asians requires an in-depth investigation of the modifiable CVD risk factors based on national and regional evidence-based findings. Herein, this review article aims to discuss several modifiable risk factors for CVDs, using epidemiological evidence from cohort studies and nationally representative data of 2 East Asian countries: Korea and Japan.
Two-Stages Sliding Fourier Transform for High Performance Phase Angle and Frequency Tracking
Osama Mohammed Arafa 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.5
Sliding discrete Fourier transform (SDFT) gives excellent performance at nominal frequency operation. However, at off - nominal frequency, it generates errors in both magnitude and phase angle due to spectral leakage. Moreover, its harmonic rejection ability is greatly impaired in this case. This paper introduces a method to apply sliding Fourier transform under off -nominal frequency at fi xed sampling rate while fi xing the defects associated with it off -nominal frequency operation. This method involves the use of two stages sliding Fourier transform (SFT). A fi xed window-width SFT in the fi rst stage is used to drive the variable window-width SFT in the second stage. The proposed technique (SFT–SFT) is tested in real time on dSPACE MicroLabBox using pre-generated voltage vectors to simulate the most inconvenient grid conditions. The testing scenarios proved its superior performance compared to the decoupled stationary reference frame PLL method.
High-Performance Elevator Traction Using Direct Torque Controlled Induction Motor Drive
Osama Mohamed Arafa,Mohamed Elsayed Abdallah,Ghada Ahmed Abdel Aziz 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.3
This paper presents a detailed realization of direct torque controlled induction motor drive for elevator applications. The drive is controlled according to the well-known space vector modulated direct control scheme (SVM-DTC). As the elevator drives are usually equipped with speed sensors, flux estimation is carried out using a current model where two stator currents are measured and accurate instantaneous rotor speed measurement is used to overcome the need for measuring stator voltages. Speed profiling for a comfortable elevator ride and other supervisory control activities to provide smooth operation are also explained. The drive performance is examined and controllers’ parameters are fine-tuned using MATLAB/SIMULINK. The blocks used for flux and torque estimation and control in the offline simulation are compiled for real-time using dSPACE Microlabox. The performance of the drive has been verified experimentally. The results show good performance under transient and steady state conditions.
Asmaa M. Arafa,Afaf E. Abdel-Ghany,Samih I. El-Dahmy,Sahar Abdelaziz,Yassin El-Ayouty,Ashraf S. A. El-Sayed 한국미생물·생명공학회 2020 Journal of microbiology and biotechnology Vol.30 No.4
Phenylalanine ammonia-lyase (PAL) catalyzes the reversible deamination of phenylalanine to cinnamic acid and ammonia. Algae have been considered as biofactories for PAL production, however, biochemical characterization of PAL and its potency for myristicin biotransformation into MMDA (3-methoxy-4, 5-methylenedioxyamphetamine) has not been studied yet. Thus, PAL from Anabaena flos-aquae and Spirulina platensis has been purified, comparatively characterized and its affinity to transform myristicin was assessed. The specific activity of purified PAL from S. platensis (73.9 μmol/mg/min) and A. flos-aquae (30.5 μmol/mg/min) was increased by about 2.9 and 2.4 folds by gel-filtration comparing to their corresponding crude enzymes. Under denaturing-PAGE, a single proteineous band with a molecular mass of 64 kDa appeared for A. flos-aquae and S. platensis PAL. The biochemical properties of the purified PAL from both algal isolates were determined comparatively. The optimum temperature of S. platensis and A. flos-aquae PAL for forward or reverse activity was reported at 30oC, while the optimum pH for PAL enzyme isolated from A. flos-aquae was 8.9 for forward and reverse activities, and S. platensis PAL had maximum activities at pH 8.9 and 8 for forward and reverse reactions, respectively. Luckily, the purified PALs have the affinity to hydroaminate the myristicin to MMDA successfully in one step. Furthermore, a successful method for synthesis of MMDA from myristicin in two steps was also established. Gas chromatography-mass spectrometry (GC-MS) analysis was conducted to track the product formation.