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Abdullahi Yakubu,Zaharaddeen Sani Gano,Omar Umar Ahmed,Suleiman Mohammed Shuwa,Abdulazeez Yusuf Atta,Baba Yakubu Jibril 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.5
Hydrophobic deep eutectic solvent (DES) was synthesized from TBAB and decanoic acid and used tostudy the extraction of aromatic hydrocarbon from contaminated water samples. DES was screened by selecting differentratios between the TBAB and decanoic acid. A ratio of 1 : 2 was observed to be the best among others and wasused for the desired application. Within the temperature range of 25-70 oC, physicochemical properties such as density(944-915 kg/m3), viscosity (1,636-179 mPa·s), conductivity (141-1,007 S/cm), and pH (3.14-2.73) of the synthesizedDES were determined. For the extraction study, benzene, toluene, and xylene (BTX)-doped water were used as a simulatedcontaminated water. Response surface methodology was employed in modeling and optimizing the effects oftemperature, time, and solvent mass fraction on the extraction efficiency of the DES. Extraction efficiency of 68.1%,70.84% and 77.73% for BTX, respectively, was recorded at optimum values of 25 oC, 60 min and 0.6 (solvent mass fraction). Extraction efficiency as high as 86.61%, 88.94%, and 92.71% for BTX, respectively, can be obtained within thedesign space. Effective regeneration and reuse of the DES after each extraction was carried out for five consecutivecycles; their results showed no significant decrease in their respective extraction efficiencies and recovery of the DES. This, therefore, improves the overall performance of hydrophobic DES for the extraction process.
Abdullahi Lawal,A. Shaari,R. Ahmed,L.S. Taura 한국물리학회 2018 Current Applied Physics Vol.18 No.5
The rapid demand of photodetector is increasing day by day due to its versatility of applications that affect our lives. However, it is still very challenging to produce low-cost high-performance broadband photo-detector that can detect light from near infrared to the ultraviolet frequency range for medical diagnosis and visible light communication applications. Regarding this, low-cost antimony selenide (Sb2Se3), with direct energy gap and strong light absorption over a wider range from near infrared to ultraviolet frequency, is considered a promising candidate material for such kind of applications. Therefore, to expose its hidden potential, detailed analysis of its structural, electronic and optical properties is very essential. To accomplish this purpose, different schemes of the first-principles calculations are used in this study. Structural properties of Sb2Se3 are calculated by first-principles methods realized within density functional theory (DFT) framework. Whereas, to compute the quasiparticle (QP) band structure, excitonic and optical properties, many-body perturbation theory (MBPT) based on oneshot GW (G0W0) and Bethe-Salpeter equation (G0W0-BSE) approaches are used. Our DFT calculations show that Wu-Cohen GGA (WC-GGA) reproduces lattice parameters of Sb2Se3 material consistent with the experimental measurements. Similarly, G0W0 calculations confirm the Sb2Se3 a direct bandgap energy material of 1.32 eV and show good agreement with the experimental results. Similarly, the results on the optical properties of Sb2Se3 with the inclusion of electron-hole interaction show that the exciton energy of the material is 1.28eV while its corresponding plasma energy is 10.86 eV. These values show that the investigated material can absorb photons from near infrared to ultraviolet wavelengths. It is, therefore, anticipated that this material will be useful for new-generation optoelectronic applications from near infrared to ultraviolet wavelengths.
Abdullahi Aminu Kazaure,Aman Jantan,Mohd Najwadi Yusoff Korea Institute of Science and Technology Informat 2024 Journal of Information Science Theory and Practice Vol.12 No.1
An online social network is a platform that is continuously expanding, which enables groups of people to share their views and communicate with one another using the Internet. The social relations among members of the public are significantly improved because of this gesture. Despite these advantages and opportunities, criminals are continuing to broaden their attempts to exploit people by making use of techniques and approaches designed to undermine and exploit their victims for criminal activities. The field of digital forensics, on the other hand, has made significant progress in reducing the impact of this risk. Even though most of these digital forensic investigation techniques are carried out manually, most of these methods are not usually appropriate for use with online social networks due to their complexity, growth in data volumes, and technical issues that are present in these environments. In both civil and criminal cases, including sexual harassment, intellectual property theft, cyberstalking, online terrorism, and cyberbullying, forensic investigations on social media platforms have become more crucial. This study explores the use of machine learning techniques for addressing criminal incidents on social media platforms, particularly during forensic investigations. In addition, it outlines some of the difficulties encountered by forensic investigators while investigating crimes on social networking sites.
Ketamine anaesthesia following premedication of rabbits with vitamin C
Abdullahi Elsa,Stephen Ubandawaki 대한수의학회 2005 Journal of Veterinary Science Vol.6 No.3
The effects of vitamin C on ketamine anesthesia was studied. In normal rabbits the onset and duration of ketamine induced anesthesia were 6.0 ± 0.5 and 36.0 ± 0.9 min, respectively. Pre-treatment of rabbits with 30, 60 and 240 mg/kg, i.m. of vitamin C followed by ketamine 40 mg/kg i.m. resulted in significant (p < 0.05) decrease in the onset and increase in duration of ketamine anesthesia to 5.0 ± 0.06 and 37.0 ± 0.7; 4.0 ± 0.5 and 39.0 ± 0.6; 2.0 ± 0.3 and 44.0 ± 0.8 min, respectively. There was also significant (p < 0.05) decrease in the heart rates in the animals treated with vitamin C and ketamine combinations. Serum analysis showed a significant (p < 0.05) increase in blood glucose. The observed decreased in serum calcium and phosphorous following ketamine injection was prevented by pretreatment with vitamin C. These results suggest that vitamin C at higher doses could potentiate ketamine anesthesia in rabbits.
Hybrid Encryption of ElGamal-AES with Huffman Coding for Efficient Data Communication
Abdullahi Yahaya Yusuf,Farouk Lawan Gambo,Hyeju Shin,Abubakar Muhamad Miyim 한국디지털콘텐츠학회 2023 The Journal of Contents Computing Vol.5 No.2
Information security or data transmission efficiency and reliability are unanimously considered as some of the most important things that are required whenever communication between parties is to be established. Inefficient data security and improper management of voluminous data during data communication increases data transmission cost, delay in data transmission, and risk of confidentiality and privacy to the transmitted data. Thus, this paper proposes an improved cryptosystem to ensure reliability and efficiency to data in communication channel. The work adopted two cryptographic methods (ElGamal cryptosystem) for the asymmetric key distribution; Advanced Encryption Standard (AES) was suggested for message encryption. In the other hand, Huffman coding (compression algorithm) was introduced along the way to reduce the size of the data to be transmitted. The results of our proposed scheme show that the entropy ensures reliability and encryption time ensures efficiency to data in communication channel. This hybrid scheme is promising with a potential of improving data security.
Simultaneous removal of particulates and NO by the catalytic bag filter containing V2O5-MoO3/TiO2
Abdullahi Abubakar,Changming Li,Lin Huangfu,Shiqiu Gao,Jian Yu 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.4
V2O5-MoO3/TiO2 based catalytic bag filters were developed for the simultaneous removal of particulates and NO in the temperature range of 200-250 oC. Good denitrification activity, dedust efficiency as well as high adhesion strength in the temperature range of 200-250 oC was exhibited. The study of catalyst powder for coating revealed that the increased V and Mo content in catalyst can elevate the low-temperature activity, and the chosen V10Mo10 sample for coating showed the best activity with 100% NO conversion at just 180 oC. The further research on catalytic bag filter found the low ratio of PTFE, high loading and long residence time (e.g., low filtration velocity or double layer filter) may help to achieve high DeNOx efficiency. The best performance was obtained with above 80% NO conversion at 200-250 oC even in the presence of SO2/H2O and 99.9% dust collection efficiency on the condition of 500 g/m2 loading, 10% PTFE, 0.5m/ min filtration velocity and double layers of filter, which demonstrated great feasibility for industrial application.