An inventory of terrestrial small mammals was conducted at five sites in southeastern Sierra Leone with the aim of documenting species diversity, abundance and distribution. Trapping was done using Sherman live traps, Victor traps, Tomahawk live traps and pitfall traps in five habitats across five sites. Based on morphological and DNA barcode-based identification, we recorded a total of 28 terrestrial small mammal species, including 20 rodents and eight shrews in 13,770 trap nights with an average trap success rate of 7 %. We document a possible country record for the rodent species Dephomys cf. eburneae , raising the total known rodent species for the country to 42 species. Furthermore, we document first country record for the shrew species Crocidura longipes , raising the total known shrew species for the country to 15. This study contributes to the knowledge and conservation of terrestrial small mammal diversity and occurrence in Sierra Leone and also provides baseline information for the five study sites. Finally, this study further demonstrates the potential importance of the study sites for conservation of terrestrial small mammals in Sierra Leone.
In this paper we investigate the Ratliff-Rush property, the reduction number, and powers of monomial ideals in multivariables. This is done by extending some tools that have been recently used for the case of two variables. These extensions allow us to give an explicit and shorter proof of the main result of Gasanova (“Powers of monomial ideals and the Ratliff–Rush operation,” J. Symbolic Comput. , vol. 104, pp. 66–89, 2020) and lead to an effective computation of the Ratliff-Rush closure. In addition, we conjecture a procedure for computing the reduction number of certain monomial ideals, and under some condition, we obtain the exact reduction number. Also, we conjecture some decompositions of the powers of ideals; this allows us to count the number of generators and hence producing ideals with consecutive tiny powers in higher dimensions.
This work performed a nonlinear numerical analysis of Armox 500T and Hardox 450 armor steels, Kevlar 29/epoxy laminate, and aluminum honeycomb materials under ballistic conditions, validating the results via experimental data. The ballistic performance of 20 distinct armor configurations was investigated, including monolithic steel, steel-composite, and steel-composite-honeycomb panels produced by various material arrangements. Ballistics tests were conducted using 7.62 × 51 mm full metal jacket bullets with a muzzle velocity of 838 ± 15 m s −1 under the NIJ 0108.01 III protection level standard. The effect of Kevlar29/epoxy layer thickness in multi-layered panels was examined extensively. The results showed that the ballistic performance of the composite armors was significantly improved due to the combination of monolithic steel plates with Kevlar 29/epoxy and aluminum honeycomb layers. Steel-Kevlar 29/epoxy and steel-Kevlar 29/epoxy-honeycomb multi-layered plates provide identical ballistic protection to monolithic steel counterparts while being 51 wt.% and 57 wt.% lighter than monolithic steel armor. Comprehensive finite element simulations of the ballistic impact events were conducted to elucidate the phenomena of defeat and penetration with greater precision.
Impact-resistant cold-work tool steels are utilized in striking tools like metal cutting dies, chisels, and hammers. Similarly, wear-resistant cast irons such as ductile iron, NiHard-4, and high-Cr-Mo white cast iron (WCI) are extensively used in mining and heavy-duty environments due to their superior hardness and microstructural stability. In this study, the microstructural characteristics and adhesive wear behaviors of nodular cast iron, NiHard-4, high-Cr-Mo WCI, and high-speed tool steels were comparatively analyzed. Microstructural phases and elemental distributions were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), elemental mapping, microhardness, and X-ray diffraction (XRD) analyses. The findings reveal that the morphology and distribution of hard carbide phases play a decisive role in wear resistance. The presence of Ni and Si decreased the interfacial energy between the carbides and the matrix, thereby promoting carbide nucleation and uniform dispersion. Consequently, finer and harder carbides formed more homogeneously, resulting in enhanced hardness and improved wear resistance. These results emphasize the critical role of alloying design in optimizing the microstructural integrity and tribological performance of cast and tool steels.
Cadmium contamination in water remains a critical environmental and health concern due to its persistence, bioaccumulative nature, and toxicity even at trace levels. In this study, commercial activated carbon (AC) was optimized as an adsorbent for Cd(II) removal using response surface methodology (RSM) based on a central composite design (CCD). The effects of adsorbent mass (0.2–1.0 g), contact time (15–75 min), and initial Cd(II) concentration (1–9 ppm) on removal efficiency were evaluated. The quadratic model demonstrated strong statistical significance ( p < 0.0001) with a high coefficient of determination (R 2 = 0.9957). The optimized conditions was 0.8 g AC, 60 min contact time, and 3 ppm initial concentration which yielded a predicted removal efficiency of 95 %. Experimental validation using optimum condition and point prediction using real sample produced an average removal of 98.19 % and RSE below 5 %, confirming the model’s reliability. FTIR analyses indicated that surface functional groups contribute to Cd(II) adsorption. The findings confirm that RSM is an effective optimization tool and that AC is a promising low-cost, high-efficiency adsorbent for Cd(II) removal.
This study involved the development of a mathematical model to simulate the structure of a head human, encompassing three layers: skin, bone, and brain. The model was designed to apply to individuals of different age groups, including both children and adults. The study utilized the concept of delay times to assess the internal thermal response occurring in the human head due to chemical processes. The governing equations were formulated within the framework of a dual phase-lag model (DPL). By applying Laplace transforms and employing a numerical approximation approach, the inverse solutions were obtained. The study focused on the effect of electromagnetic waves emitted by cellular device on the human head. The variations of temperature within the head were calculated and analysed considering different parameters such as energy density, power transmission frequency, and different heat conduction models. Notably, the power waves density and power transmission frequency due to the electromagnetic wave have significant impacts on the temperature increments and the thermal damages quantity passing through the three studied layers of both adult’s and child’s heads. Moreover, the differences between the three studied heat conduction are major. The comparative evaluation among Pennes, SPL, and DPL models is presented.
The current model explores the role of dual simulations of Casson fluid and Sisko fluid in mass diffusion and heat energy on expanding and shrinking disk, considering tri- and hybrid nano-fluid, which investigates the performance between fluid flow and heat energy for the cases of the lower branch and the upper branch. The correlations of tri, mono and di nanofluid are called Hamilton Crosser and Yamada Ota models. The desired form of PDEs (partial differential equations) is obtained using transformations. The numerical simulations of ODEs (ordinary differential equations) are attained using a finite element approach. Soret and Dufour influences are considered with Joule heating and thermal conductivity (variable). Such a model is applicable in heat exchangers, thermal insulation, and engine cooling systems. The Taguchi approach is used for heat transfer rate. The results reveal the simulations of motion, concentration and heat energy in view tables, graphs and contour graphs. Skin friction and temperature gradient are discussed for UBS (upper branch solution) and LBS (lower branch solution) with various parameters. The opposite trend in momentum boundary layer thickness occurs when N and Ba are enhanced. The mass diffusion can be reduced when Sc and Kc are enhanced.
Rutting in asphalt concrete is a widespread phenomenon affecting the strength and overall performance of pavements, especially in regions with intense environmental variabilities and transitions, where excessive temperatures and heavy traffic loads exacerbate pavement deformation. This study reviews and synthesizes research on the causes, consequences, and mitigation strategies for rutting with a particular emphasis on Saudi Arabia’s asphalt pavements. Key factors contributing to rutting, advanced asphalt mixtures, and environmental conditions were extensively discussed. Moreover, the work explores the current pavement design requirements, particularly in Saudi Arabia, highlighting unique policies aimed at addressing rutting issues. Comparisons with other nations with relatively distinct climatic challenges were equally addressed to provide a broader understanding of global exceptional practices. The review also identifies key areas for future research, coupled with the development of superior asphalt mixtures, the incorporation of revolutionary components, and the implementation of tracking technology. By consolidating knowledge on rutting in Saudi Arabia, this review aims to inform and guide ongoing and future efforts to enhance pavement overall performance and durability in the region. In the end, recommendations were proposed based on materials, environmental impact, sustainability, and soil conditions that are essential for effective utilization in Saudi Arabia and other countries in the Arabian Peninsula.