Effect of Gravel Size and Weir Height on Flow Properties of Gabions

لقد تم دراست العلاقة بين عمق الماء المتجمع امام السداد الحجرية والتصريف القادم من اعالي المجاري المائية في قناة مختبرية. حيث تم دراسة السطح الحر للماء في حالة التدفق الانتقالي وفي حالة الفيضان فوقه. تضمنت الدراسة تأثير ارتفاع جسم السداد الحجرية وخشونة المواد المستخدمه في الانشاء على عمق تدفق المنبع عن طريق اختبار أربعة ارتفاعات مختلفة من الهدارات وأربعة أحجام مختلفة من الحصى. أظهر تحليل النتائج المختبرية أن الانخفاض النسبي في عمق الماء المتجمع امام الهدارات يتراوح ما بين 38٪ و17٪ لنوع الجريان " التدفق خلال " عندما يزداد كل من خشونة المادة والتصريف، وفي نظام "التدفق الانتقالي"، تؤدي زيادة خشونة المواد والتصريف إلى انخفاض متوسط في عمق التدفق النسبي بين 7.6٪ و4.4٪ لارتفاع الهدارات الحجرية 15 سم و30 سم، على التوالي. يبدأ السداد الجرية في العمل كهدار يفيض الماء من فوقه عندما يكون متوسط عمق الماء إلى ارتفاع السداد (H / P) هو 1.19، في حين أن متوسط الزيادة الإجمالية في التصريف نسبة إلى تصريف السد الصلب هو 15 ٪. كما تم أقتراح علاقات تجريبية للتنبؤ بعمق الماء المتجمع أمام السداد الحجرية لكل من أنظمة التدفق الثلاثة. كما تم اقتراح علاقة تجريبية عديمة الابعاد للتنبؤ بمعامل التصريف لهذة السداد وبدقة جيدة.The variation between flow depth generated in front of gabion barrier and flow rate has been studied in open laboratory flume. Flow profiles have been observed for each of "Transition Flow" and "Overflow" regimes. Effects of gabion height and material coarseness on the upstream flow depth are studied by testing four different gabion heights and four different medium aggregate sizes. The analysis of experimental results showed that the relative decrease in flow depth varies between 38% and 17% for "Through Flow" type when material coarseness and discharge increase. In "Transition Flow" regime, increasing material coarseness and discharge causes an average decreases in relative flow depth of 7.6% and 4.4% for gabion heights 15cm and 30cm, respectively. Gabion begins to operate as an overflow weir when the average water depth to the gabion height (H/P) is 1.19. While the overall average increase in discharge relative to solid weir is 15%. Prediction relationships for flow depth upstream the gabion for each of the three flow regimes is suggested. Also, dimensionless relation to predict discharge coefficient are proposed with good accuracy

Process optimization of methylene blue adsorption onto eggshell-treated palm oil fuel ash

Palm oil fuel ash (POFA) and eggshell (EG) were explored towards efficient methylene blue (MB) removal. Calcined EG, with a high content of CaO was used as a low-cost activation replacement for the alkali treatment of POFA. The adsorption performance of EG–POFA was studied by comparing its performance with untreated POFA, calcined EG and commercially treated Ca–POFA, and the competency was following the order of EG < POFA < EG–POFA ≈ Ca–POFA, indicating that EG effectively enhanced the efficiency of POFA. The response surface methodology (RSM) was executed to optimize the operating conditions of MB adsorption onto EG–POFA by investigating the effect of EG–POFA dosage (X1), initial pH (X2) and initial MB concentration (X3) towards MB removal (Y). X1=1.18 g/L, X2=6, and X3=182 mg/L, with Y=80.36% were found to be optimal conditions. The experimental data disclosed that the MB adsorption onto EG–POFA was in accordance with the Langmuir isotherm model (qm=714.29 mg/g) and followed pseudo-second-order kinetic model. The thermodynamic study discovered the endothermic and spontaneous natures of MB adsorption onto EG–POFA. This study discovered the feasibility of EG as an eco-friendly activation alternative for the alkali treatment towards remarkable MB adsorption

Effect of Ni-Ta ratio on the catalytic selectivity of fibrous Ni-Ta/ZSM-5 for dry reforming of methane

A series of Ni-Ta catalysts supported on fibrous ZSM-5 were synthesized by microemulsion and impregnation method. Catalytic activity and selectivity were influenced by incorporation of Ta into Ni catalyst. The side reaction (Boudouard, methane cracking, and reverse water gas shift reaction) tests gave more insights on source of coking, where 10Ni catalyst was more inclined towards methane cracking. The 7Ni-3Ta catalyst showed the best performance (CO2 and CH4 conversions of 95% and 93%, respectively) due to the inherent activity of Ni, and anti-sintering impact of Ta as affirmed by TEM and Raman spectra. Its TGA analysis revealed 9.8% carbon content after 100 h. Furthermore, activation energy of CO2 and CH4 conversions were reduced by 15% and 10% respectively. Thus, addition of small amount of Ta to Ni catalyst was able to dilute Ni surface and limit the degree of graphitization of carbon which is prerequisite for stable performance in DRM

The unforeseen relationship of Fe2O3 and ZnO on fibrous silica KCC-1 catalyst for fabricated Z-scheme extractive-photooxidative desulphurization

Fibrous silica KAUST Catalysis Centre (KCC-1) was prepared via a hydrothermal-microwave method, followed by incorporation of Fe2O3 and ZnO by an electrochemical technique to give ZnO-Fe2O3/KCC-1 (ZFK) catalysts. XRD, FESEM, N2 physisorption, FTIR, XPS, ESR and UV–Vis DRS were employed to characterize the catalysts. A varied amount of Fe2O3 and ZnO seems have insightful impact on the physicochemical behaviours of the KCC-1 while prominently enhanced the extractive-photooxidative desulphurization of dibenzothiophene (DBT). 5Z10FK demonstrated the best performance mainly due to a well distribution of both metal oxides on KCC-1, the highest Si-O-Fe and Si-O-Zn bonds, an appropriate amount of surface defect and suitable band gap energy. Besides, the suitable band positions of 10FK and 5ZK in 5Z10FK composite has allowed the formation of Z-scheme heterojunction for conserved strong redox potential. Kinetic studies revealed that the adsorption of DBT was the rate determining step, thus this reaction obeyed the Langmuir-Hinshelwood pseudo-first order

Shari’ah Compliance as a Matter for Financial Performance

Islamic banks must comply with the Shari'ah rulings fully as it is the foundation of Islamic banks. However, the level of Shari'ah compliance is not the same among the Islamic banks. Similarly, despite performing well, the financial performances of Islamic banks differ from each other. Therefore, the chapter explores the association between financial performance and Shari'ah compliance. The chapter used both the primary and secondary data. The primary data was collected through surveying 300 bank executives from six full-fledged Islamic banks operated in Bangladesh with a structured questionnaire on Shari'ah compliance, whereas information on financial performance were extracted from the annual reports of the sample banks. Descriptive statistics and regression analysis were used to analyze the data and conclude the findings. The findings show that Shari'ah compliance has a positive and significant impact on the financial performance with respect to the total liabilities and total assets.</p