On-line measurement and simulation of the in-core gamma energy deposition in the McMaster nuclear reactor

Mohammed Alqahtani 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.1

In a nuclear reactor, gamma radiation is the dominant energy deposition in non-fuel regions. Heat is generated upon gamma deposition and consequently affects the mechanical and thermal structure of the material. Therefore, the safety of samples should be carefully considered so that their integrity and quality can be retained. To evaluate relevant parameters, an in-core gamma thermometer (GT) was used to measure gamma heating (GH) throughout the operation of the McMaster nuclear reactor (MNR) at four irradiation sites. Additionally, a Monte Carlo reactor physics code (Serpent-2) was utilized to model the MNR with the GT located in the same irradiation sites used in the measurement to verify its predictions against measured GH. This research aids in the development of modeling, calculation, and prediction of the GH utilizing Serpent-2 as well as implementing a new GH measurement at the MNR core. After all uncertainties were quantified for both approaches, comparable GH profiles were observed between the measurements and calculations. In addition, the GH values found in the four sites represent a strong level of radiation based on the distance of the sample from the core. In this study, the maximum and minimum GH values were found at 0.32 ± 0.05 W/g and 0.15 ± 0.02 W/g, respectively, corresponding to 320 Sv/s and 150 Sv/s. These values are crucial to be considered whenever sample is planned to be irradiated inside the MNR core.

The Role of Technology in Facilitating, Connecting, and Ending CYBERCRIME, Drug Trafficking, and Money Laundering

Mohammed AlQahtani,Raymond Doug Partin,Back Sin-chul,Jo Sung-gu J-INSTITUTE 2019 International Journal of Terrorism & National Secu Vol.4 No.2

This research investigates and shows how technology helped to facilitate and to connect three types of trans-national crimes. More specifically, cybercrimes, drug trafficking, and money laundering. Moreover, technology has helped to facilitate cybercrimes by basically giving birth to them; without the evolution of technology, we would not have had cybercrimes. When ICTs(Information and communication technology) showed up, people all over the world can now have access to the internet which can make some of them vulnerable to cybercriminals. Examples of cybercrimes can include hacking, Ransomware, Identity theft, phishing emails, Internet Crime Against Children(ICAC), industrial espionage, and fraud. As for drug trafficking, technology has helped to facilitate this type of cybercrime by basically giving dealers and consumers a safe atmosphere where they can make deals and payments from anywhere in the world without the need of physical appearance which makes them less exposed to getting arrested. Examples of electronic drug trading are the hidden market places in the darknet. As for money laundering, technology has provided money launderers the ability to establish online offshore companies and banks that have fewer restrictions on money laundering; this method helps criminals to wash their money in countries with no or few laws that prohibit and investigate unknown income sources. Furthermore, technology has provided online banking which gives people the ability to make online transactions; cybercrimi-nals can easily blend their illicit transactions with the illicit ones with less chance of getting noticed. Other than facilitating those crimes, technology has also helped to connect those three types of crimes. Cy-bercriminals help drug dealers with coding and providing cyberspace, both cybercriminals and drug traffickers launder their money to have legit unquestionable income. As for recommended policy implications, nations should keep updating their laws in order to properly prose-cute those types of crimes, more education for law enforcement agencies should by implied as well along with more awareness to the public to avoid victimization.

Spectroscopic and cloud point studies of the interaction and thermodynamics of ciprofloxacin hydrochloride+surfactants mixture in different solvents: Effect of temperature and composition

Md. Anamul Hoque,Md. Mofaqkharur Rahman,Shamim Mahbub,Mezbah Hossain,Mohammed Abdullah Khan,Md. Ruhul Amin,Ali S. Alqahtani,Mohammad Z. Ahmed,Mohammed S. Alqahtani,Omar M. Almarfadi 한국화학공학회 2021 Korean Journal of Chemical Engineering Vol.38 No.7

Surfactant is one of the most important chemical entities in drug formulation which can bind with drug molecules. Herein, the binding interaction of ciprofloxacin hydrochloride (CFH) drug with two different surfactants (sodium dodecyl sulfate (SDS) and Triton X-100 (TX-100)) has been investigated through UV-Visible spectroscopic and cloud point measurement techniques at different conditions. The absorption spectrum of CFH was found to be dependent on presence of additives/temperature change. The binding constant (Kb) of CFH+SDS/CFH+TX-100 was found to be increased primarily, reached a maximum value and then decreased with the increase of temperature, except in water medium (pH=2.0) and 30% (v/v) methanol. The Kb values for CFH+SDS were found to be higher in the aqueous medium than almost all medium studied herein, while better binding was observed in the alcoholic medium in the case of the CFH+TX-100 system. The Gibbs free energy of binding (Gb o) for both CFH+SDS and CFH+TX- 100 systems were attained negative in each case studied, inferring the spontaneous binding phenomenon. The cloud point (CP) value of CFH+TX-100 mixture was lessened in ZnSO4·7H2O solution and the CP values exhibited a gradual reduction through the upsurge of electrolyte concentration. The positive values of the Gibbs free energy of clouding indicated the nonspontaneous clouding phenomena. To disclose the interaction between drug and surfactant, other thermodynamic parameters, e.g., enthalpy (Hb o) and entropy (Sb o), different transfer energies as well as entropyenthalpy compensation parameters of binding/clouding were evaluated and clarified with proper explanation.

Comparative study of mechanical behavior of low- and high-density polyethylene based on UVB sterilization for medical usage

Mohamed A. Aboamer,Ahmed A. Aboamer,Doaa H. Elgohary,Tarek M. Alqahtani,Ahmed Abdel-Hadi,Samiya M. Al-Mutairi,Tarek M. El-Bagory,Khaled M. Alshareef,Nader A. Rahman Mohamed 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

The aim of this research is to investigate the sterilizing effect of UVB radiation on the degradation and oxidation of low- and high-density polyethylene specimens using ASTM 638 and 695. Polyethylene is a reliable, efficient, and low-cost biomaterial and an alternative to various bone transplants. Twenty high-density polyethylene (HDPE) specimens and twenty low-density polyethylene (LDPE) specimens were used for tensile and compression testing. The dosage of 13.5 J/cm 2 was chosen with an exposure time of 48 minutes during the sterilization process. In terms of mechanical tensile properties, LDPE has a lower effect compared with HDPE. The p-value of yield stress equals 3.008×10 -4 , the p-value of ultimate stress equals 2.5×10 -4 , and the p-value of break stress equals 0.0075.

Physical characterization and radiation shielding features of B2O3-As2O3 glass ceramic

Mohamed Y. Hanfi,Ahmed K. Sakr,A.M. Ismail,Bahig M. Atia,Mohammed S. Alqahtani,K.A. Mahmoud 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.1

The synthetic B2O3eAs2O3 glass ceramic are prepared to investigate the physical properties and the radiation shielding capabilities with the variation of concentration of the As2O3 with 10, 20, 30, and 40%, respectively. XRD analyses are performed on the fabricated glasseceramic and depicted the improvement of crystallinity by adding As2O3. The radiation shielding properties are studied for the B2O3eAs2O3 glass ceramic. The values of linear attenuation coefficient (LAC) are varied with the variation of incident photon gamma energy (23.1e103 keV). The LAC values enhanced from 12.19 cm1e37.75 cm1 by raising the As2O3 concentration from 10 to 40 mol% at low gamma energy (23.1 keV) for BAs10 and BAs40, respectively. Among the shielding parameters, the halfevalue layer, transmission factor, and radiation protection efficiency are estimated. Furthermore, the fabricated samples of glass ceramic have low manufacturing costs and good shielding features compared to the previous work. It can be concluded the B2O3eAs2O3 glass ceramic is appropriate to apply in X-ray or low-energy gamma-ray shielding applications.

Vibration analysis of FG cylindrical shell: Evaluation of Ritz-polynomial mixed with ring terms

Mohamed A. Khadimallah,Muzamal Hussain,Muhammad Nawaz Naeem,Amjad Qazaq,Abdulaziz Alqahtani,Abdelouahed Tounsi 국제구조공학회 2021 Smart Structures and Systems, An International Jou Vol.27 No.5

Here the Rayleigh - Ritz method has been applied to derive the shell vibration frequency equation. This equation has been formed as an eigenvalue problem form. MATLAB software package has been utilized for extracting shell frequency spectra. Nature of materials used for construction of cylindrical shells also has visible impact on shell vibration characteristics. For isotropic materials, the physical properties are same everywhere, the laminated and functionally graded materials vary from point to point. Here the shell material has been taken as functionally graded material. Moreover, the impact of ring supports around the shell circumferential has been examined for the various positions along the shell axial length. These shells are stiffened by rings in the tangential direction. These ring supports are located at various positions along the axial direction round the shell circumferential direction. These variations have been plotted against the locations of ring supports for three values of exponents of volume fraction law. For three conditions, frequency variations show different behavior with these values of exponent law. The influence of the positions of ring supports for simply supported end conditions is very visible. The frequency first increases and gain maximum value in the midway of the shell length and then lowers down. The comparisons of frequencies have been made for efficiency and robustness for the present numerical procedure.

Size-controlled biofabrication of silver nanoparticles using the Merremia emarginata leaf extract: Toxicity on Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus (Diptera: Culicidae) and non-target mosquito predators

Raja Mohamed Sait Thameem Azarudeen,Marimuthu Govindarajan,Mashael Marzouq AlShebly,Fatma Saeed AlQahtani,Abubucker Amsath,Sengamalai Senthilmurugan,Periasamy Vijayan,Giovanni Benelli 한국응용곤충학회 2017 Journal of Asia-Pacific Entomology Vol.20 No.2

Mosquito-borne diseases represent a major human and animal health problem in all tropical and subtropical countries worldwide. The synthesis of eco-friendly metal nanoparticles is a fast-growing branch of current nanoscience with a number of biomedical and entomological implications. In this study, we investigated the one-pot synthesis of silver nanoparticles (Ag NPs) using a cheap leaf extract of Merremia emarginata (Convolvulaceae). Bio-reduced Ag NPs were characterized by UV–visible spectrophotometry, Fourier transform infrared spectroscopy, X-ray diffraction analysis, atomic force microscopy, scanning electron microscopy and transmission electron microscopy. SEM, TEM and AFM morphological nanocharacterization showed that this synthesis led to the production of size-controlled Ag NPs, ranging from 25 to 65 nm. The acute toxicity of M. emarginata leaf extract and biosynthesized Ag NPs was evaluated against third instar larvae of the malaria vector Anopheles stephensi, the dengue and Zika virus vector Aedes aegypti and the filariasis vector Culex quinquefasciatus. Compared to the leaf aqueous extract, Ag NPs showed higher toxicity against A. stephensi, A. aegypti, and C. quinquefasciatus with LC50 values of 8.36, 9.20 and 10.02 μg/mL, respectively. M. emarginata-fabricated Ag NPs were found safer to non-target aquatic biocontrol agents Anisops bouvieri, Diplonychus indicus and Gambusia affinis, with LC50 ranging from 415.61 to 25,153.46 μg/mL. However, although it has been proven the AgNPs fabricated in the present study are more effective if compared to the crude M. emarginata extract, they still exert some toxicity on biocontrol agents, thus further research is required to produce more eco-friendly formulations for field purposes.

Assessment of Sustainable Green Lightweight Concrete Incorporated in New Construction Technologies

Fahad K. Alqahtani,Mohamed A. Sherif,Amr M. Ghanem,Ibrahim S. Abotaleb 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.12

Recent studies have led to the development of approaches for recycling plastic waste and using it as an alternative for natural aggregates in concrete. The studies mainly focused on the material properties and sustainability aspects of such implementation, with little focus on the financial implications and the technical feasibility. The purpose of this research is to investigate the different lifecycle costs associated with the use of green recycled plastic lightweight aggregates (GLACs) in concrete construction in different structural systems. For that purpose, the authors evaluated a concrete structure with several variable design systems and conducted structural design once using conventional concrete and once using concrete with recycled plastic aggregates, resulting in a total of 36 distinct scenarios. The lifetime cost analysis was performed on such scenarios. Finally, a sensitivity analysis was carried out to determine how structural characteristics and critical element costs influence cost-effectiveness. According to the findings, this approach can save up to 6% in life-cycle expenses. The findings of this research will contribute to the upcoming paradigm shift of using recycled plastic in concrete, which will reduce the environmental impacts of both the concrete and plastic industries while also assisting developers in lowering their life cycle costs.

Epidemiological Trends of Histopathologically WHO Classified CNS Tumors in Developing Countries: Systematic Review

Khan, Ishaq,Bangash, Mohammed,Baeesa, Saleh,Jamal, Awatif,Carracedo, Angel,Alghamdi, Fahad,Qashqari, Hanadi,Abuzenadah, Adel,AlQahtani, Mohammed,Damanhouri, Ghazi,Chaudhary, Adeel,Hussein, Deema Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.1

Background: Many developing countries are lagging behind in reporting epidemiological data for individual central nervous system (CNS) tumors. This paper aimed to elicit patterns for the epidemiology of individual World Health Organization (WHO) classified CNS tumors in countries registered by WHO as "developing". Materials and Methods: Cyber search was carried out through 66 cancer networks/registries and 181 PubMed published papers that reported counts of CNS tumors for the period of 2009-2012. The relationship between the natural log of incidence Age Standardized Rate (ASR) reported by Globocan and Latitude/ Longitude was investigated. Results: Registries for 21 countries displayed information related to CNS tumors. In contrast tends for classified CNS tumor cases were identified for 38 countries via 181 PubMed publications. Extracted data showed a majority of unclassified reported cases [PubMed (38 countries, 45.7%), registries (21 countries, 96.1%)]. For classified tumors, astrocytic tumors were the most frequently reported type [PubMed (38 countries, 1,245 cases, 15.7%), registries (21 countries, 627 cases, 1.99%]. A significant linear regression relationship emerged between latitudes and reported cases of CNS tumors. Conclusions: Previously unreported trends of frequencies for individually classified CNS tumors were elucidated and a possible link of CNS tumors occurrence with geographical location emerged.

Assessment of radioactivity levels and radiation hazards in building materials in Egypt

Ahmed E. Abdel Gawad,Mohamed Y. Hanfi,Mostafa N. Tawfik,Mohammed S. Alqahtani,Hamed I. Mira Korean Nuclear Society 2024 Nuclear Engineering and Technology Vol.56 No.2

Different degrees of natural radioactivity found in quartz can have negative consequences on health. Quartz vein along the investigated Abu Ramad area, Egypt, had its natural radioactivity assessed. The HPGe spectrometer was used to determine the role played by the radionuclides ²³⁸U, ²³²Th, and ⁴⁰K in the gamma radiation that was emitted, and the results showed that these concentrations are 484.64 ± 288.4, 36.8 ± 13.1 and 772.2 ± 134.6 Bq kg^-1 were higher than the corresponding reported global limits of 33, 45, and 412 Bq kg^-1 for each radionuclide (²³⁸U, ²³²Th, and ⁴⁰K). Among the radiological hazard parameters, the excess lifetime cancer risk (ELCR) is estimated and it's mean value of ELCR (1.2) is higher than the permissible limit of 0.00029. The relationship between the radionuclides and the associated radiological hazard characteristics was investigated based on multivariate statistical methods including Pearson correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA). According to statistical research, the radioactive risk of quartz is primarily caused by the ²³⁸U, ²³²Thand ⁴⁰K. Finally, applying quartz to building materials would pose a significant risk to the public.