In situ Transesterification/Reactive Extraction of Castor Bean Seeds Assisted by Flying Jet Plasma for Biodiesel Production

Elsheikh, Yasir A.,Abdul-Majeed, Wameath S.,Nasir, Qazi,Al-Rahbi, Balaqis,Al-Subhi, Noor,Mahmoud, Mohamed A.,AAl-Thani, Ghanim S. The Korean Society of Industrial and Engineering C 2022 공업화학 Vol.33 No.5

One of the most exciting areas for the development of alternative fuels is the production of biodiesel. To reduce the cost of biodiesel production, in situ trans-esterification has been introduced to simplify the production process by enabling extraction and trans-esterification to occur at a single stage in the presence of a catalyst. In this study, we investigated the feasibility of using non-corrosive and environmentally receptive flying jet plasma as an alternative catalytic route for in situ tran-sesterification of castor bean seeds (CBS). Upon optimizing the reaction conditions, it is elucidated that applying a low ratio of methanol to seeds (≤6:1) has resulted in hindering the in situ trans-esterification and leading to insignificant conversion. The yield of esters has increased from 80.5% to 91.7% as the molar ratio rose from 9:1 to 12:1. Excess alcohol beyond the ratio of 15:1 was shown to have a negative impact on the yield of the produced esters, attributed to an increase in the biodiesel portion prone to dissolving in the co-product (glycerol). An increase in the reaction bulk temperature from 40 to 55 ℃ led to a higher ester content by 50%. Further increases in the bulk temperature beyond 55 ℃ did not affect yields. Regarding the reaction period, the results have shown that 3 h of reaction is adequate for a higher biodiesel yield. The quality of the biodiesel obtained has demonstrated that all physicochemical properties meet the ASTM D6751 specifications.

Comparative optimization of Be/Zr(BH4)4 and Be/Be(BH4)2 as 252Cf source shielding assemblies: Effect on landmine detection by neutron backscattering technique

Elsheikh Nassreldeen A.A. 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.7

Monte Carlo simulations were used to model a portable Neutron backscattering (NBT) sensor suitable for detecting plastic anti-personnel mines (APMs) buried in dry and moist soils. The model consists of a 100 MBq 252Cf source encapsulated in a neutron reflector/shield assembly and centered between two 3 He detectors. Multi-parameter optimization was performed to investigate the efficiency of Be/Zr(BH4)4 and Be/Be(BH4)2 assemblies in terms of increasing the signal-to-background (S/B) ratio and reducing the total dose equivalent rate. The MCNP results showed that 2 cm Be/3 cm Zr(BH4)4 and 2 cm Be/3 cm Be(BH4)2 are the optimal configurations. However, due to portability requirements and abundance of Be, the 252Cf2 cm Be/3 cm Be(BH4)2 NBT model was selected to scan the center of APM buried 3 cm deep in dry and moist soils. The selected NBT model has positively identified the APM with a S/B ratio of 886 for dry soils of 1 wt% hydrogen content and with S/B ratios of 615, 398, 86, and 12 for the moist soils containing 4, 6, 10, and 14 wt% hydrogen, respectively. The total dose equivalent rate reached 0.0031 mSv/h, suggesting a work load of 8 h/day for 806 days within the permissible annual dose limit of 20 mSv

Esophageal Motility Abnormalities in Lung Transplant Recipients With Esophageal Acid Reflux Are Different From Matched Controls

( Mazen Elsheikh ),( Lekan Akanbi ),( Lisbeth Selby ),( Bahaaeldeen Ismail ) 대한소화기기능성질환·운동학회 2024 Journal of Neurogastroenterology and Motility (JNM Vol.30 No.2

Background/Aims There is an increased incidence of gastroesophageal reflux disease (GERD) after lung transplantation (LT) that can be associated with graft dysfunction. It is unclear if the underlying esophageal motility changes in GERD are different following LT. This study aimed to use esophageal high-resolution manometry (HRM) to explore GERD mechanisms in LT recipients compared to matched controls. Methods This was a retrospective study including patients with pathologic acid reflux who underwent HRM and pH testing at our healthcare facility July 2012 to October 2019. The study included 12 LT recipients and 36 controls. Controls were matched in a 1:3 ratio for age, gender, and acid exposure time (AET). Results LT recipients had less hypotensive esophagogastric junction (EGJ) (mean EGJ-contractile integral 89.2 mmHg/cm in LT vs 33.9 mmHg/cm in controls, P < 0.001). AET correlated with distal contractile integral and total EGJ-contractile integral only in LT group (r = -0.79, P = 0.002 and r = -0.57, P = 0.051, respectively). Conclusions Following LT, acid reflux is characterized by a less hypotensive EGJ compared to controls with similar AET. The strongest correlation with AET after LT was found to be esophageal peristaltic vigor. These results add to the understanding of reflux after LT and may help tailor an individualized treatment plan. (J Neurogastroenterol Motil 2024;30:156-165)

An acidic ionic liquid-conventional alkali-catalyzed biodiesel production process

Yasir Ali Elsheikh,Zakaria Man,Faheem Hassan Akhtar 한국화학공학회 2014 Korean Journal of Chemical Engineering Vol.31 No.3

A study was undertaken to prepare biodiesel via two-step process using ionic liquid as first step catalystdue to the unsuitability of using the straight alkaline-catalyzed transesterification of high FFA presented in crude palmoil (CPO). In the first step, esterification of the FFA presented in the CPO was carried out using butylimidazolium hydrogensulfate (BIMHSO4), in which the acid value was reduced from 6.93 to 1.02mg KOH/g and then, KOH-catalyzedtransesterification was applied. The conversion rate of FFA attained 85.3% when 4.8 wt% of BIMHSO4 was appliedto the reaction system containing methanol to CPO ratio of 12 : 1 reacted at 170 oC for 150min. The final yield in 97.3%revealed that the process proposed in this study could lead to an excellent biodiesel meeting the ASTM requirements. Furthermore, this new two-step catalysis process could solve the old conventional catalysis process drawbacks.

An overview of the role of ionic liquids in biodiesel reactions

Nawshad Muhammad,Yasir A. Elsheikh,Muhammad Ibrahim Abdul Mutalib,Zakaria Man,Ihsnullah khan,Aqeel Ahmed Bazmi,Rahmat Ali Khan,Hidayatullah Khan,Sikander Rafiq 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

The concerns on the depleting petroleum resources and increasing environmental problems have driventhe scientific community worldwide to develop large-scale non-petroleum-based alternative fuels, suchas bioethanol and biodiesel. Biodiesel produced through the transesterification of vegetable oils oranimal fats are highly attractive. On the other hand, ionic liquids which possess properties that aremoreenvironmental friendly have found significant applications as solvents and catalysts for reaction andseparation. It is also beginning to find its way in many of the chemical process applications and hasattracted significant attention including biodiesel production. This paper provides a brief overview onthe feasibility of applying ionic liquids in biodiesel production for the purpose of powering diesel enginesfor transportation and utility generation. The potential of applying ionic liquids as catalyst and solventfor enzymatic production of biodiesel from feedstock is particularly highlighted.

Reflections on the Mobilities, Immobilities, Inequalities, and Traveling Ideas in Qatar

Keith M. Graham,Aymen Elsheikh,Zohreh R. Eslami 아시아영어교육학회 2020 The Journal of Asia TEFL Vol.17 No.2

PWM Control Techniques for Single-Phase Multilevel Inverter Based Controlled DC Cells

Sayed, Mahmoud A.,Ahmed, Mahrous,Elsheikh, Maha G.,Orabi, Mohamed The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This paper presents a single-phase five-level inverter controlled by two novel pulse width modulation (PWM) switching techniques. The proposed PWM techniques are designed based on minimum switching power loss and minimum total harmonic distortion (THD). In a single-phase five-level inverter employing six switches, the first proposed PWM technique requires four switches to operate at switching frequency and two other switches to operate at line frequency. The second proposed PWM technique requires only two switches to operate at switching frequency and the rest of the switches to operate at line frequency. Compared with conventional PWM techniques for single-phase five-level inverters, the proposed PWM techniques offer high efficiency and low harmonic components in the output voltage. The validity of the proposed PWM switching techniques in controlling single-phase five-level inverters to regulate load voltage is verified experimentally using a 100 V, 500 W laboratory prototype controlled by dspace 1103.

PWM Control Techniques for Single-Phase Multilevel Inverter Based Controlled DC Cells

Mahmoud A. Sayed,Mahrous Ahmed,Maha G. Elsheikh,Mohamed Orabi 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.2

This paper presents a single-phase five-level inverter controlled by two novel pulse width modulation (PWM) switching techniques. The proposed PWM techniques are designed based on minimum switching power loss and minimum total harmonic distortion (THD). In a single-phase five-level inverter employing six switches, the first proposed PWM technique requires four switches to operate at switching frequency and two other switches to operate at line frequency. The second proposed PWM technique requires only two switches to operate at switching frequency and the rest of the switches to operate at line frequency. Compared with conventional PWM techniques for single-phase five-level inverters, the proposed PWM techniques offer high efficiency and low harmonic components in the output voltage. The validity of the proposed PWM switching techniques in controlling single-phase five-level inverters to regulate load voltage is verified experimentally using a 100 V, 500 W laboratory prototype controlled by dspace 1103.

Group B Streptococcus Colonization, Antibiotic Susceptibility, and Serotype Distribution among Saudi Pregnant Women

Amr Mohamed Mohamed,Mubashir Ahmad Khan,Aftab Faiz,Jawwad Ahmad,Elsheikh Babiker Khidir,Mohammed Abubakar Basalamah,Akhmed Aslam 대한감염학회 2020 Infection and Chemotherapy Vol.52 No.1

Background: Group B Streptococcus (GBS) comprises the normal flora of the female urogenital tract and can be transferred to neonates during delivery, causing invasive diseases. This study was performed to investigate the colonization rate, antibiotic susceptibility, and serotype of GBS among Saudi pregnant women. Materials and Methods: In this cross-sectional study, vagino-rectal swabs from 400 pregnant women were collected over a period of one year. Identification of GBS isolates and determination of their antibiotic susceptibility were performed using the Microscan Walk Away system. The isolates were then typed using both latex agglutination and capsular genebased multiplex polymerase chain reaction assays. Results: Sixty (15.0%) subjects were colonized by GBS, with serotype Ia as the dominant type (30.0%) followed by serotype III and V (25.0%, each). Only 43 (71.7%) isolates were typed by latex agglutination, whereas the remaining isolates were not typable or were non-specifically typed as compared to the genotyping assay, which revealed the specific type of each GBS isolate. The highest resistance rates were observed for erythromycin and clindamycin (16.7%, each), which were mainly restricted to the prevalent serotypes. Conclusion: This study is the first to report the distribution of GBS serotypes based on molecular genotyping in Saudi Arabia. GBS colonization was evident among pregnant women, and resistance to erythromycin and clindamycin was predominant among serotypes Ia, III, and V. Molecular genotyping using capsular gene-based multiplex PCR provided reliable typing of the investigated GBS isolates in terms of sensitivity and specificity as compared to conventional serotyping using latex agglutination.

Heart failure in children and adolescents: an update on diagnostic approaches and management

Amit Agrawal,Dalwinder Janjua,Abdulrahman Ahmed Alsayed Ali Zeyada,Ahmed Taher Elsheikh 대한소아청소년과학회 2024 Clinical and Experimental Pediatrics (CEP) Vol.67 No.4

Cardiac failure is a clinical syndrome that may develop in children owing to cardiac dysfunction or underlying structural heart diseases. Considering the differences indiagnostic and therapeutic approaches for pediatric heart failure (PHF) and adult heart failure, we have reviewed the current literature on PHF. Relevant studies wereextracted from MEDLINE/PubMed, Google Scholar, and Clinical Trial Registries using the terms “pediatric heart failure” or “heart failure in children” and “management” or “decongestive therapy.” Recent advances in diagnosticapproaches, such as cardiac magnetic resonance, speckletracking echocardiography, tissue Doppler imaging, and molecular diagnostic techniques, have increased our understanding of PHF.Itis imperative that clinicians evaluate the interrelated factors responsible for the development of PHF, including myocardial function, pulmonary and systemic blood flow, heart rhythm, valve function, and nutritional status. Although recent advances have demonstrated the efficacy of many new drugs in adult heart failure trials, it cannot be concluded that these drugs will show similar efficacy in children, considering the heterogeneous nature of the underlying mechanisms and variable pharmacodynamics and pharmacokinetics. Therefore, the underlying pathophysiology of PHF and the mechanisms of actionof different drugs should be considered when selecting appropriate therapies.Further trials areneededto establish the efficacy and safety of these drugs, and a combined multidisciplinary strategy will help enhance PHF outcome