Visible-light-driven photocatalytic water oxidation catalysed by iron-based metal–organic frameworks

Horiuchi, Yu,Toyao, Takashi,Miyahara, Kenta,Zakary, Lionet,Van, Dang Do,Kamata, Yusuke,Kim, Tae-Ho,Lee, Soo Wohn,Matsuoka, Masaya The Royal Society of Chemistry 2016 Chemical communications Vol.52 No.29

<P>An iron-based metal-organic framework, MIL-101(Fe), promotes photocatalytic water oxidation to produce oxygen from aqueous silver nitrate solution under visible-light irradiation. The finely dispersed iron-oxo clusters embedded as nodes of the porous framework would contribute importantly to the efficient promotion of the reaction as compared to bulk hematite (alpha-Fe2O3).</P>

Evaluating ecotourism assets in the Cameroonian cities hosting the 33rd edition of the Africa Cup of Nations

Zakari Aretouyap,Janvier Domra Kana,Franck Eitel Kemgang Ghomsi,Mirelle Flore Chamba Nana 대한공간정보학회 2022 Spatial Information Research Vol.30 No.3

Considering the African Cup of Nations (AfCoN) as an important tourism opportunity, the present article aims to advertise Cameroon’s touristic potential by assessing the ecological conditions of 11 cities hosting matches of the competition and their respective dance patrimony. In addition to the urban thermal field variance index (UTFVI), the land surface temperature (LST) was computed. Both parameters are derived from Landsat-8 OLI images using a combined GIS-remote sensing method and spatially represented. According to the UTFVI values, the ecological conditions are at least acceptable everywhere except a thin zone in Ngaoundere where conditions are bad. Minimum values of UTFVI in those cities are respectively -0.12, -0.22, -1.05, -0.14, -0.08, -0.06, -0.50, -0.77, -0.50, -0.57 and -0.12 while maximum values are respectively 0.23, 0.29, 0.23, 0.14, 0.42, 0.11, 20, 0.35, 21, 56 and 0.14. LST range from 10 C (in Douala with a max value of 27 C) to 71 C (in Foumban with a min value of 59 C). Each city under study has a set of traditional dances that can attract potential visitors. The article contributes to the promotion of sustainability and ecotourism in Cameroon on the occasion of the 33rd AfCoN edition.

Contractors' Perception towards Safety and its Consequences on Construction Workers in Cape Coast Metropolis

Mustapha, Zakari Korea FoodHealth Convergence Association 2019 식품보건융합연구 (KJFHC) Vol.5 No.6

The construction environment has been declared as a hazard prone area due to high number of accident and death. The study aims to identify influential factors that contribute to poor safety practices and its consequences on construction workers in Cape Coast Metropolis. Seventy respondents were taken as the sample size for the study. Descriptive analysis was used to analyze the data obtained from the field. Findings show that poor site management, working without safety gadgets, failure to use their Personal Protective Equipment (PPE) and negligence of workers were the main causes of accidents on sites. Poor site management had the highest ranking among the seven variables. Effects of poor safety practices on building construction site and delays in work execution were due to injury of workers, extra cost due to payment of compensation to injured victims, not motivated due to injury of worker and declined reputation of firm. Management team should motivate workers for safe work done, provide adequate PPE for their workers on site and have documented health and safety policy on site. Site authorities and management team should be on site regularly to ensure proper safety practices on construction site.

Does Aid Effectiveness Differ per Political Ideologies?

Vincent Konadu Tawiah,Evans John Barnes,Abdulrasheed Zakari 한국국제경제학회 2019 International Economic Journal Vol.33 No.2

Despite the extensive empirical literature on aid effectiveness, existing studies have not addressed directly how political ideology affects the use of foreign aid in the recipient country. This study, therefore, uses a unique dataset of 12 democratic countries in Africa to investigate the impact of political ideologies on aid effectiveness. Our results indicate that each political party uses aid differently in peruse of their political, ideological orientation. Further analyses suggest that rightist capitalist parties are likely to use aid to improve the private sector environment. Leftist socialist on the other hand, use aid effectively on pro-poor projects such as short-term poverty reduction, mass education and health services. Our additional analysis on the lines of colonialisation shows that the difference in the use of aid by political parties is much stronger in French colonies than Britain colonies. The study provides insight on how the recipient government are likely to use foreign aid.

Protective effect of fisetin against subchronic chlorpyrifos-induced toxicity on oxidative stress biomarkers and neurobehavioral parameters in adult male albino mice

Akpa Amaka Rosita,Ayo Joseph Olusegun,Mika’il Hudu Garba,Zakari Friday Ocheja 한국독성학회 2021 Toxicological Research Vol.37 No.2

Chlorpyrifos (CPF), a chlorinated organophosphate insecticide that is widely used in agriculture and public health, has neurotoxic effects in animals. In addition to acetylcholinesterase inhibition, CPF has been shown to induce alterations such as oxidative stress and lipid peroxidation. Fisetin is a dietary flavonol that protects the brain tissue against oxidative stress by modulating the activity of antioxidant enzymes. This study was designed to investigate the protective role of fisetin against brain oxidative damages and neurobehavioral parameters induced by subchronic oral exposure to CPF in albino mice. Adult albino mice (males, n = 32, weighing 20 ~ 25 g) were assigned randomly into 4 groups and treated accordingly for 7 weeks as follows: Group 1(S/OIL): served as the control group and were given 2 ml/kg of soya oil; Group 2 (CPF): received CPF (6.6 mg/kg; 1/5th of the LD50); Group 3 (FIS): fisetin (15 mg/kg) and Group 4 (FIS + CPF): received fisetin at 15 mg/kg, followed by CPF (6.6 mg/kg) 30 min later. Co-treatment with FIS + CPF mitigated the increase in brain malondialdehyde concentration (0.28 ± 0.02 nmol/mg) and orchestrated the increase in the activities of catalase (81.35 ± 7.26 μ/ mg), superoxide dismutase (93.03 ± 6.63 IU/mL), glutathione peroxidase (68.76 ± 3.554 nmol/mL) and acetylcholinesterase (11.59 ± 0.72 nmol/min/mL) when compared to the CPF group. The result showed that deficits in motor strength and excitability scores induced by subchronic CPF were mitigated by fisetin administration. It was concluded that fisetin has a protective potential in mitigating against oxidative stress and damages in the brain tissues, induced by subchronic exposure to CPF in adult male albino mice.

Stress intensity factors for double-edged cracked steel beams strengthened with CFRP plates

Hai-Tao Wang,Gang Wu,Yu-Yang Pang,Habeeb M. Zakari 국제구조공학회 2019 Steel and Composite Structures, An International J Vol.33 No.5

This paper presents a theoretical and finite element (FE) study on the stress intensity factors of double-edged cracked steel beams strengthened with carbon fiber reinforced polymer (CFRP) plates. By simplifying the tension flange of the steel beam using a steel plate in tension, the solutions obtained for the stress intensity factors of the double-edged cracked steel plate strengthened with CFRP plates were used to evaluate those of the steel beam specimens. The correction factor <i>α</i>₁ was modified based on the transformed section method, and an additional correction factor <i>φ</i> was introduced into the expressions. Threedimensional FE modeling was conducted to calculate the stress intensity factors. Numerous combinations of the specimen geometry, crack length, CFRP thickness and Young's modulus, adhesive thickness and shear modulus were analyzed. The numerical results were used to investigate the variations in the stress intensity factor and the additional correction factor <i>φ</i>. The proposed expressions are a function of applied stress, crack length, the ratio between the crack length and half the width of the tension flange, the stiffness ratio between the CFRP plate and tension flange, adhesive shear modulus and thickness. Finally, the proposed expressions were verified by comparing the theoretical and numerical results.

Recent progress in the preparation, characterization, and applications of modified halloysite nanotubes as adsorbents for wastewater treatment

Garba Zaharaddeen Nasiru,Haruna Abdurrashid,Tanimu Abdulkadir,Bello Binta Zakari,Zango Zakariyya Uba 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.6

The application of halloysite nanotubes (HNTs) in water purification is attracting extensive attention because they are inexpensive raw materials with a hollow nanotubular structure in the sub-micrometer range, a large specific surface area, pore volume, pore size, and adequate hydroxyl groups on their surface, thus enhancing their ability to be modified. These modified halloysite nanotubes (m-HNTs) have been widely used for a variety of applications, including chemocatalysis, biocatalysis, antibacterial action, drug delivery, gas separation, and adsorbents for wastewater treatment. They were reported to have been produced using a variety of synthetic processes which include self-assembly/vacuum filtering, extraction, solution casting, dehydration condensation, thermal polycondensation, chemical vapor deposition, and hydrothermal carbonization. In this review, we focus on the compilation of the most recent developments in the manufacture of m-HNTs, their characterization and possible uses in wastewater treatment. Finally, we present our personal views on the opportunities and challenges of future researches involving m-HNTs, hoping to inspire more researchers into participating in this fascinating area.