This work focuses on the extraction and experimental characterization of pennisetum purpureum fibers extracted from stems and roots, harvested in the Batié Kingdom, in the West Region of Cameroon. After extracting fibers using the boiling water technique, they are chemically treated to improve their properties and performance and to facilitate their incorporation into various composite materials. For the physical characterizations, it is measured: the absolute and apparent densities, the linear mass, the water absorption rate, and the diameter via the microscope. The mean values of the diameters and the measure of their frequency distributions are calculated, followed by the statistical analysis using the maximum entropy principle, in order to find the most probable diameter necessary for technological applications. For the mechanical properties, only the tensile tests are performed, with the determination of the young modulus of both the stems and roots. The results thus obtained showed that the fibers of the stems have an absolute density of (1.35 g/cm3), a linear mass of (54.6 tex), an apparent density of (0.45 g/cm3), a water content of (12.73%), an absorption rate of (142.46%), a porosity of (65.91%), a mean diameter of (7 mm), an elastic modulus of (3.98 GPa), a tensile strength of value of (1186.59 MPa) and an elongation of 16.17%, while the root fibers have an absolute density of (1.34 g/cm3), a linear mass (16.76 tex), an apparent density of (0.37845 g/cm3), a water content of (12.25%), an absorption rate of (193.16%), a porosity of (71.92%), a diameter of (4 mm), an elastic modulus of (1.55 GPa), a tensile strength of a value of (1960.35 MPa) and an elongation of 60.6%. Thus, the fibers of the stems have good mechanical properties, which make them an appropriate material in several applications, such as the reinforcement of composite materials.

In the relentless evolution of technological innovation, the incorporation of engineered materials across numerous sectors is becoming increasingly widespread. Among them, ultra-high molecular weight polyethylene (UHMWPE) fiber, as a novel type of engineered material, has emerged as a critical hot topic in industries such as aerospace, national defense, and new energy due to its exceptional physical and chemical properties. This article attempts to introduce the characteristics of UHMWPE fibers, including their advantages and areas for enhancement, to provide researchers with a comprehensive overview and research trajectory of UHMWPE. Moreover, this article succinctly elucidates the preparation methodologies and advances of UHMWPE fibers, encompassing mainstream dry and wet spinning methods, revealing their research trajectories, pivotal positions, and practical significance in the realm of engineered materials. In summary, this review briefly discusses the research overview and recent advances in UHMWPE fibers, which contribute to accelerating comprehensive and sustainable progress in this field.

In order to enhance the value of local materials and contribute to reducing construction costs in Cameroon, rattan waste is used to reinforce compressed earth blocks (CEB). This main work’s objective is the study of the effect of rattan waste on the physical and mechanical properties of CEB. For this, a soil sample taken in the western region of Cameroon, more precisely in Bangangté, was analyzed, the analysis includes the granulometric analysis, the Atterberg limits, and the Proctor test. Then the CEB samples with different rattan waste contents, that is 0%, 2%, 4% and 6%, were developed for a compaction stress of 7.5 MPa. These different samples were characterized through mechanical and physical tests carried out in the laboratory. It appears that the blocks reinforced with 2% of rattan waste have better mechanical characteristics, respectively 0.70 MPa in three-point bending and 3.04 MPa in compression. On the other hand, the presence of rattan wastes has a positive effect on the mechanical behavior of the composite, by increasing its ductility compared to the fragile behavior of the control block, which is observed during crushing. Thus the mechanical properties of CEB improve with the incorporation of rattan waste, which is optimal for a content of 2%. But they increase the material's porosity, and then its sensitivity to water unlike the control CEB.

The microstructure and negative differential resistance (NDR) effect of nitrogen implanted rutile TiO2 were investigated by measuring the XPS, Raman spectra and current voltage curves. It was found that the light illumination has large influence on the NDR effect. Under the illumination of 60 mW laser light, a large NDR with a small electric field (1250 V/cm) is obtained. This electric field is about three orders smaller than that reported in literature (1×106 V/cm). The electric field induced tunneling is the possible mechanism of electric transport at higher field region. The NDR is thought to be related to the light and nitrogen dopant induced reaction including the destroying of water, the scavenging of electron, and the surface oxidation transform of non-stoichiometric TiO2−x to stoichiometric insulating state. The results of this paper are not only useful in understanding the mechanism of NDR, but also useful in providing an effective method in manipulation NDR.

Solid oxide fuel cells (SOFCs) are renowned for being effective energy sources that have potential to influence how energy is developed in future. SOFCs operate at low temperatures provides different benefits for widespread commercialization. In the present study a perovskite material Pr0.6Sr0.4Fe0.8Co0.2O3−δ (PSFCo) was investigated as cathode for SOFC in intermediate temperature range. Glycine nitrate process was used for the preparation of the samples. PSFCo exhibited cubic structure having small particle size (100–200 nm). The electrical conductivity of the PSFCo was measured as function of temperature up to 850 ℃. The sample displayed maximum electrical conductivity of 370 Scm−1 at around 550–600 ℃. The polarization behavior of PSFCo was calculated by means of AC impedance with Sm0.8Ce0.2O2 (SDC) as electrolyte. The value of area specific resistance (ASR) was calculated as 0.146 Ωcm2 at 800 ℃ and 0.248 Ωcm2 at 700 ℃.

In this study, Zr-doped HfO2 (HZO) based resistive random-access memory (RRAM) device were fabricated. The Hf:Zr (1:1) ratio in the HZO films were controlled by changing the HfO2 and ZrO2 cycle ratio during the atomic layer deposition (ALD) process. Next, we studied the structural and electrical properties of the Au/HZO/TiN RRAM device structure. The RRAM devices exhibits an excellent resistance ratio of the high resistance state (HRS) to the low resistance state (LRS) of ~103 A, and as well as good endurance (300 cycles) and retention (>103 s), respectively. Further, the device showed different conduction mechanism in LRS and HRS modes. The lower biased linear region is dominated by ohmic conductivity, whereas the higher biased nonlinear region is dominated by a space charge limited current conduction. This device is suitable for application in future high-density nonvolatile memory RRAM devices.

Only a few nanomedicines have entered clinical application after over a decade and billions of dollars of investments in nanoscience and nanotechnology around the world. So, what lower the development of nanodrug? Recently, at our recent Editorial and Editorial Advisory Board meeting, we asked ourselves to address these questions and accelerate the development of nano pharmaceuticals. We will work with leaders in the area of drug supply to share our experiences and compare efforts around the world.

In this study, Buxus sempervirens leaf ingredient (LP) and the carbon (LC) and the ash (LA) were obtained, which are the bio-originated materials. Carbon and ash obtained from this natural plant were prepared by heating and pyrolysis for 2 h at 250 ℃ and 700 ℃, respectively. Then, the solution casting method was used to prepare the composites of these bio-additives with polystyrene. Next, the effects of the additives on diffuse reflectance spectroscopy (DRS) and X-ray diffraction (XRD) spectra of polystyrene were investigated. In addition, the additives led to noticeable changes in X-ray diffraction results, implying a change in the morphology of the polymer. All of these observations imply the uniform formation of the polystyrene (PS) composites with the micro and bio-fillers.

This study examined the surfaces of non-passivated and passivated tinplate samples, as well as the impurities present on them, using SEM, EDS, and GDOES. Additionally, solutions were analyzed using ICP in order to identify any correlations between the elements present in the solutions and on the strip surfaces. The results from GDOES indicated the presence of unwanted elements, such as Sn, S, Cr, N, P, Zn, Fe, Mn, C, and Si, on both the passivated and non-passivated sample surfaces. SEM analysis of the passivated sample revealed light and dark regions in parallel lines, which were observed ahead of the rolling direction. EDS analysis indicated that the light areas were rich in Sn while the dark areas were rich in Fe, and C was identified as an unwanted element in both areas. O and Cr were only found in the dark areas. EDS analysis of the impurities revealed Na, S, Cl, Ca, Mg, Si, N, and Al as unwanted elements. The results suggest that unwanted elements are transferred from the steel strip surface to different solutions in the tinplate line, causing pollution in various solutions.

This study compared gas-metal arc welding (GMAW) and laser beam welding (LBW) for the superposed joining of two low-carbon steels. The motivation was to reduce the visible defects (notches) in the external part of one of the sheets. Both welding processes produced sound welds characterized by ferrite and pearlite; however, the notch disappeared when LBW was used. The hardness values of the fusion and heat-affected zones were similar for both processes, but the tensile strengths were very different. The shear tensile strengths of the LBW and GMAW were 415 and 84 MPa, respectively. Finite element analysis simulations indicated a more diffuse distribution of the von Mises stress throughout the welded component. The GMAW FEA model also presented a defect because of excessive heat transfer and residual stresses. In conclusion, LBW can replace GMAW in this particular case with improvements in appearance, productivity, and mechanical strength.