Mechanical Properties of Kenaf/Polyester Composites

In this study, the reinforced kenaf fibers using polyester resin composites were processed through vacuum infusion method. Before infusion and reinforced applied, the long kenaf fibers were treated by various concentration of sodium hydroxide(NaOH). The effects of the modification on fiber and also the effect of fiber alkalization on composites then is analyzed for mechanical properties and by using the scanning electron microscopy (SEM). The results showed that the alkalization treatment has improved the mechanical properties of the composites as compared to the composites with untreated kenaf fiber. In addition, a general trend of the mechanical performances of alkalized kenaf fiber composites observed showed increase with the increments of NaOH concentration. In this study, the vacuum infusion method used also offers benefits over hand lay-up method due to the better fiber to resin ratio that resulting in stronger and lighter laminates. By vacuum infusion process, the kenaf-polyester composite manufactured provides an opportunity for replacing the existing materials with a higher strength, low cost alternatives, and environmental friendl

Current trends in MXene-based nanomaterials for energy storage and conversion system: A mini review

MXene is deemed to be one of the best attentive materials in an extensive range of applications due to its stupendous optical, electronic, thermal, and mechanical properties. Several MXene-based nanomaterials with extraordinary characteristics have been proposed, prepared, and practiced as a catalyst due to its two-dimensional (2D) structure, large specific surface area, facile decoration, and high adsorption capacity. This review summarizes the synthesis and characterization studies, and the appropriate applications in the catalysis field, exclusively in the energy storage systems. Ultimately, we also discussed the encounters and prospects for the future growth of MXene-based nanomaterials as an efficient candidate in developing efficient energy storage systems. This review delivers crucial knowledge within the scientific community intending to design efficient energy storage systems.The publication of this article was funded by Qatar National Library. This work was carried by the NPRP grant # NPRP11S-1221-170116 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors. The publication of this article was funded by the Qatar National Library.Scopu

Fabrication of zno-fe-mxene based nanocomposites for efficient co2 reduction

A ZnO-Fe-MXene nanocomposite was fabricated and examined with diverse spectroscopic techniques. The hexagonal structure of ZnO, MXene, and ZnO-Fe-MXene nanocomposites were validated through XRD. FTIR showed the characteristic vibrational frequencies of ZnO and MXene. The micrographs of the SEM showed nanoparticles with a flower-like structure. The electrocatalytic reduction efficiency of ZnO-Fe-MXene nanocomposite was analyzed through cyclic voltammetry and electrochemical impedance spectroscopy methods. The ZnO-Fe-MXene electrode was confirmed to have a high current density of 18.75 mA/cm2 under a CO2 atmosphere. Nyquist plots also illustrated a decrease in the impedance of the ZnO-Fe-MXene layer, indicating fast charge transfer between the Zn and MXene layers. Additionally, this electrochemical study highlights new features of ZnO-Fe-MXene for CO2 reduction.Funding: This work was carried by the NPRP grant # NPRP11S-1221-170116 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Immune function in female B6C3F1 mice is modulated by DE-71, a commercial polybrominated diphenyl ether mixture

Polybrominated diphenyl ethers (PBDEs) are an important class of flame-retardants that are environmentally persistent and bioaccumulative. Toxicity of these compounds has become a concern because detectable levels of PBDEs are present in humans and wildlife and they are structurally similar to polychlorinated biphenyls (PCBs). This study examined the effects of the commercial penta-BDE mixture, DE-71, in adult female B6C3F1 mice on hematology, serum clinical chemistry, thyroid hormones, tissue histology, and several immunotoxicity end-points (lymphocyte proliferation, NK cell activity, splenic immunophenotypes, and SRBC-specific-IgM production). Mice were exposed via oral gavage for 28 days to achieve total administered doses (TAD) of 0, 0.5, 5, 50, or 100 mg/kg. No changes in histology, clinical chemistry, body or organ weights were observed. Serum total T3 and T4 levels were not altered by any of the DE-71 treatments. Peripheral blood monocyte numbers were decreased by the 0.5, 5, and 50 mg/kg treatments, but not by the 100 mg/kg TAD concentration. Compared to controls, mitogen-stimulated T- and B-cell proliferation was increased by the 100 mg/kg TAD concentration (ED50 = 60 mg/kg TAD [2.14 mg/kg/day] and 58 mg/kg TAD [2.57 mg/kg/day], respectively). NK cell activity was decreased compared to controls by the 100 mg/kg TAD concentration (ED50 = 20 mg/kg TAD [0.7 mg/kg/day]). No alterations were noted in thymic T-cell populations or in SRBC-specific-IgM production. Numbers of CD19+CD21−, CD19+CD21+, CD4+CD8−, CD4−CD8+, CD4−CD8−, and MHC-II+ cells in the spleen were not affected. However, the numbers of splenic CD4+CD8+ cells were decreased compared to the controls by 0.5, 5, and 100 mg/kg TAD. This study provides an assessment of the systemic toxicity and immunotoxicity of DE-71, and indicates that immune parameters are modulated at exposure concentrations lower than previously reported

A Reverse Logistics Network Model for Handling Returned Products

58827Due to the emergence of e-commerce and the proliferation of liberal return policies, product returns have become daily routines for many companies. Considering the significant impact of product returns on the company’s bottom line, a growing number of companies have attempted to streamline the reverse logistics process. Products are usually returned to initial collection points (ICPs) in small quantities and thus increase the unit shipping cost due to lack of freight discount opportunities. One way to address this issue is to aggregate the returned products into a larger shipment. However, such aggregation increases the holding time at the ICP, which in turn increases the inventory carrying costs. Considering this logistics dilemma, the main objectives of this research are to minimize the total cost by determining the optimal location and collection period of holding time of ICPs; determining the optimal location of a centralized return centre; transforming the nonlinear objective function of the proposed model formulation by Min et al. (2006a) into a linear form; and conducting a sensitivity analysis to the model solutions according to varying parameters such as shipping volume. Existing models and solution procedures are too complicated to solve real-world problems. Through a series of computational experiments, we discovered that the linearization model obtained the optimal solution at a fraction of the time used by the traditional nonlinear model and solution procedure, as well as the ability to handle up to 150 customers as compared to 30 in the conventional nonlinear model. As such, the proposed linear model is more suitable for actual industry applications than the existing models.S