The processes involved to extract chitosan biopolymers from natural resources often employ hazardous chemicals and long processing time. This work provides a sustainable direct extraction method of chitosan from snail shells. Previous attempts using acetogenin in graviola extracts succeeded in the extraction of chitosan from marine shells. However, the slow reaction has prompted the addition of hydrogen bond acceptor solution into the graviola extract. Choline chloride is an excellent hydrogen bond acceptor mixed with acetogenin as hydrogen bond donor to form natural deep eutectic solvent (NADES) for the direct extraction of chitosan. Chitosan obtained from this method has a degree of deacetylation of 91% and a molecular weight of 481 kDa with fiber-like morphology. The direct extraction of chitosan from NADES consisting of choline chloride and acetogenin has proven to extract chitosan with comparable properties to commercial chitosan.

The website of higher educational institutes is considered a vital communication channel to provide main resources to their stakeholders. It plays an important role in disseminating information about an institute to a variety of visitors at a time. Thus, the quality of an academic website requires special attention to respond to the users’ demands. This study aims to explore the quality of the PSAU website based on data mining techniques. The first step: was collecting opinions about the PSAU website using a survey. After that, data mining processes were used as descriptive and predictive models. The descriptive model was applied to describe and extract the major indicators of website quality. Besides, the predictive model was applied to create models for predicting the website quality level. More than one classification algorithm was used. Naive Bayes and Support Vector Machine have given the best results in all performance indicators, and the achieved accuracy rate for both algorithms was 86% and 84% respectively. The results revealed that the overall quality level of the PSAU website is very good. The usability quality and content quality were very good. The service quality needs more attention. which indicated that the service level is inadequate and needs to be further enhanced. The results of the study should be useful to the deanship of Information Technology at PSAU, and website developers, in redesigning with high quality in terms of its usability, content, and service.

This study used 30 cm long packed by 3 kg soil columns to explore the effects of peat, compost, and charcoal at 5% on the movement of fipronil (99.9 % purity) in clay loam soil and sandy clay loam soil. The soil columns were preconditioned with calcium chloride solution (0.01 M) before applying the pesticide and potassium iodide. Potassium iodide solution (0.2 M) was added at a rate of 10 mL as a water tracer and a quantity of fipronil solution (10 µg g^-1soil) was applied on the soil surface of each column. Next, fipronil was leached from the soil columns with a calcium chloride solution (0.1 M) and the leachates were collected and analyzed. The results show that water tracer I^- leached fast in soil columns. The breakthrough curve of fipronil appeared from leachates of soil columns after iodide for a while, indicating that fipronil is a moderate or lower mobile compound depending on type of soil and type of soil amendments. In general, adding soil amendments (peat, compost, and charcoal) to clay loam soil and sandy clay loam soil resulted in improved fipronil adsorption and decreased the amount of fipronil that leached into groundwater. This study is very useful for preserving groundwater from pollution, especially in the Middle East due to the lack of water sources.

In the present work, we synthesized new thiosemicarbazone based Schiff base ligands and their Mn(II), Ni(II), Cu(II) and Zn(II) complexes. The synthesized compounds were characterized and their antimicrobial activities were studied. Elemental analysis, IR, ¹H-NMR and mass spectrometry were done to fully characterize all the compounds. The ligands and their complexes were screened for in-vitro biological study against Gram positive (Bacillus subtilis) and Gram negative (E. coli, Klebsiella pneumonia, Pseudomonas aeruginosa) bacteria for the Zone of Inhibition method. The thiosemicarbazone based complexes showed better activity than the ligands.

In 2019, the COVID-19 epidemic swept throughout the globe. The virus was first identified in Wuhan, China. By the time several months had gone by, this virus had spread to numerous locations throughout the world. Consequently, this virus has become a worldwide pandemic. Multiple efforts have been made to limit the transmission of this virus. A possible course of action is to lock down the territory. Unfortunately, this strategy wrecked the economy, worsening the terrible situation. The world health organization (WHO) would breathe a sigh of relief if there were to be no new cases. However, the government should explore employing data from the future in addition to the data it already has. Prediction of time series may be utilized for this purpose. This study indicated that the Gaussian processes method outperformed the least median squared linear regression method (LMSLR). Applying a Pearson VII-based global kernel produces MAE and RMSE values of 23.12 and 53.43, respectively.

As customers' orientation towards environmental products increases, manufacturers and other members of the supply chain are looking for ways to conduct their operations in an environmentally and cost-effective manner. To find a solution that compensates these requests, a game theoretical approach is developed for a two-stage green supply chain consisting of a supplier and a producer. A Stackelberg game model based on asymmetric information structure is developed to find the optimal lot sizes and raw material sales price for raw material supplier, and the product sales price and the environmental cost for the producer. The developed approach is illustrated on a real-world case study that deals with production and raw material procurement processes of a plastic plug and compared to a scenario in which no environmental expenditures exist. The effect of changes in the model has been observed by tuning some significant parameters with the experimental design approach.

A potentiometric titration study has been undertaken to determine the cationic surfactant influence on mixed ligand complexes in ternary systems consisting of cobalt (II), nickel (II), copper (II), and zinc (II) with aspartic and citric acids at various concentrations (0.0–2.5% w/v) of the CTAB (Cetyltrimethyl ammonium bromide)-surfactant solution while maintaining an ionic strength of 0.16 mol L^-1 (NaCl) at 30 °C. Titrations were performed in the presence of different ratios (M:L:X = 1:2:2, 1:4:2, and 1:2:4) of metal (M) and aspartic acid (L) to citric acid (X) using sodium hydroxide. Model systems were developed based on statistical parameters and residual analysis. For Co(II), Ni(II), Cu(II), and Zn(II), the species detected were MLXH₂, MLX₂H₅, and MLX₃. The electrostatic relationship of the ligands' side chains, charge neutralization, chelate effect, stacking interactions, and hydrogen bonding are used to explain the trend in the variation of logarithm of stability constants (log β) values with changing dielectric constant and mole fraction of the surfactant. The variation in species distribution as a function of pH and surfactant composition is also presented and discussed, as are plausible equilibria for the formation of the species and structures of the ternary complexes are also presented and discussed.

The purpose of this article is to investigate the effect of various process parameters such as compaction pressure, sintering temperature, and time on the physio-mechanical properties of a powder metallurgy-fabricated composite made of pure aluminium/alumina. Temperatures (580°C, 600°C, and 630°C), periods (1.5, 2, and 2.5 hr), compacting loads (30KN-65KN), and alumina percentages (2, 4, 6, and 8weight percent) are all considered. X-ray diffraction (XRD) and X-ray fluorescence spectroscopy (XRF) studies are carried out to determine the phases present and their proportions. Crystallite size study is performed using XRD data, and the Al+4 weight % alumina composite has the smallest size of any composite tested. For optimization, sintering density, porosity, and microhardness are calculated. Scanning electron microscopy (SEM) is used to analyse the different microstructures. At 600°C, 2 hr of operating time, and 4weight% alumina additions, the highest sintering density and microhardness are found.

This study considers an integrated inventory planning and distribution problem based on an applied case at the Turkish Red Crescent’s Central Anatolian Regional Blood Center. We define two echelons, the first echelon being the regional blood center and the second echelon being the districts. The blood products are perishable so that the outdated products are disposed of at the end of their lives. We aim to minimize the cost of inventory keeping at both echelons, the shortage, and disposal amounts at the second echelon. We consider two distribution strategies: all deliveries are realized by the regional blood center (current implementation), and the deliveries are directly from the regional blood center or the other districts. We develop a mixed-integer linear programming model for each strategy. Our experimental results show that the decentralized strategy brings significant cost reductions over the centralized strategy. The mathematical model for the centralized distribution strategy can handle large-sized instances. On the other hand, the model for the decentralized distribution strategy is more complex and could not handle large-sized instances in our pre-specified termination limit of two hours. For large-sized instances of the decentralized distribution strategy, we design a decomposition-based heuristic algorithm that benefits from the optimal solutions of the original model and finds near-optimal solutions very quickly.

The interaction of nicotinic acid and thiourea with the chloride salts of Ca(II), Mg(II), Co(II), Ni(II), Cu(II), and Fe(III) ions led to the synthesis of a unique series of metal chelates. All formed metal complexes were clarified using a variety of analytical and spectral techniques, besides magnetic moment and thermal tests. The electronic and magnetic measurements indicated that the paramagnetic chelates (3) and (4), as well as the diamagnetic complexes (1) and (2), were responsible for the tetrahedral geometrical structure. The outcomes also led to the production of square-planar, and high-spin octahedral structures for chelates (5) and (6). Thermodynamic studies using activation energy values revealed that complex (1) is more thermally stable than complex (2) and complex (3) is more stable than complex (4). Fe(III) complex exhibits higher antibacterial and antifungal activities than other metal complexes. Chelate (6) exhibits the highest rate of germination in wheat.