Search

Decarbonizing heat-intensive industries by reusing the waste heat for power or combined heat and power systems is becoming increasingly important to address global warming. The Organic Rankine Cycle has shown a high level of feasibility and performed efficiently for utilizing medium-to-low-grade heat from renewable resources and heat-intensive industries for direct power generation. This study contributes to the field by conducting a techno-economic investigation of various Organic Rankine Cycle configurations to enhance energy conversion when real-life transient waste heat sources are available. These configurations were optimized to maximize energy output along with economic benefits. The non-linear programming by quadratic Lagrangian, a computational unintensive yet accurate optimization algorithm, was utilized for the multi-objective optimization. The optimized cycle configurations showed a 12.57% enhancement of turbine efficiency. Combining regeneration and recuperation enhanced the superheating by 32%, and the optimized air preheater cycle improved the overall objective by 64.2% compared to the pre-optimized conventional cycle, leading to a feasible 1.72-year payback period. [ABSTRACT FROM AUTHOR]

This study presents a pioneering methodology for the synthesis of aluminum matrix composites (AMCs) fortified with biochar, sourced from renewable biomass feedstocks. Employing a systematic approach, various biochar weight percentages were meticulously investigated to discern their impact on the mechanical and tribological properties of the resulting composites. Through a comprehensive battery of tests, encompassing evaluations of compressive strength and hardness, the study elucidated significant enhancements in mechanical robustness consequent to biochar integration. Notably, the mixture formulation with 7.5 wt. % biochar emerged as the optimal configuration, showcasing an impressive 8.83% augmentation in compressive strength and a notable 15% elevation in the hardness relative to the pristine aluminum pure matrix. The research extends beyond traditional analyses, introducing an exploration of tribological performance. The incorporation of biochar is anticipated to impart solid lubricating properties, influencing wear and friction characteristics. Future research directions may delve into the nuanced interplay between biochar content and tribological enhancements, offering insights into the tailored manipulation of mechanical and tribological properties in AMC through biochar reinforcement. The examination of wear and friction exhibited that the friction coefficient decreased by 6.4% when 10 wt. % of biochar was added. Furthermore, the wear resistance improved proportionally with the biochar weight percentage, regardless of the normal loads applied. The finite element model further demonstrated an enhancement in load-carrying capacity due to biochar incorporation. Finally, analysis of the texture of the rubbed surface presented that the inclusion of biochar in an AL matrix changed the way wear occurs and decreased the amount of weight lost during friction. The resulting materials not only exhibit improved mechanical strength but also hold promise for applications in industries that demand robust, environmentally conscious solutions with enhanced tribological performance. [ABSTRACT FROM AUTHOR]

Ankle and foot orthotics are suggested for gait rehabilitation therapy after a stroke. Clinical practice necessitates adjusting the ankle foot orthosis torque to accommodate each patient's unique stride and body function. The objective of this paper is to develop a customized, cost-effective footplate orthosis from carbon fibers, manufactured using 3D printing, for individuals with partial foot amputations. The footplate is designed for use in developing nations and aimed to be made available with a reduced lead time. The experiment work carried out in this research is used to design, analyze, and validate a prosthetic footplate. A foot of size UK 7 with a 2 mm thick model of the human foot was modeled using Unigraphics-NX. The footplate's design is being tested both conceptually and empirically. The footplate manufactured by applying load at toe and heel shows that the carbon fiber successfully restores leg length and reduces pressure on the feet's delicate distal end. [ABSTRACT FROM AUTHOR]

This study investigates the enhancement of mechanical and tribological behavior in polymethyl methacrylate (PMMA) composites reinforced with graphene oxide (GO) as a solid lubricant filler for advanced biomedical applications, particularly dental implants. PMMA/GO composites were prepared with varying weight percentages of GO (0, 0.2, 0.5, 0.7, and 1 wt. %) to assess their impact on material performance. A noteworthy improvement in both tensile strength and Young's modulus was detected, reaching up to 141% and 10.6%, respectively, at optimized GO loadings of 1%. Microstructural analysis utilizing scanning electron microscopy for the worn surface revealed enhanced dispersion and interfacial adhesion between GO and the PMMA matrix, reinforcing mechanical coherence. Tribological properties also demonstrated enhancement, with PMMA composites containing 1 wt. % GO exhibiting optimal mechanical and tribological characteristics compared to lower weight fractions. Moreover, microscopic examination revealed a shift in the wear mechanism of the PMMA-GO composite, which was attributed to the lower friction coefficient obtained by GO integration. [ABSTRACT FROM AUTHOR]

This research work highlights the tribomechanical investigations of using a low loading fraction of two ceramics combinations, Alumina (Al2O3) and Silicon Carbide (SiC) as reinforcement for Low-density Polyethylene (LDPE) matrix. The hybrid additives with different weight percentages (0.1 + 0.1, 0.25 + 0.25 and 0.5 + 0.5 wt%) were mixed with LDPE matrix and the degree of homogeneity was controlled using double-screw extruder prior to fabricating the composite samples via the injection molding machine. The nanoparticles fillers were characterized by field emission scanning electron microscope (FESEM), EDX and particle size analyzer to check its morphology, composition and size distribution. Thermogravimetric analyzer (TGA) and melting flow index (MFI) were performed for the fabricated nanocomposites samples. The mechanical properties of the nanocomposite were evaluated by performing tensile test, bending test and Shore-D hardness test, while the tribological performance was investigated using a ball on desk apparatus under different applied loads and sliding times. Moreover, in order to confirm the load-carrying capability of the composite, contact stresses was measured via finite element model using ANSYS software. The results show that the incorporation of low fraction hybrid ceramic nanoparticles can contributed positively in the tribological and mechanical properties. Based on the experimental results, the maximum improvement in the tensile strength was 5.38%, and 8.15% for hardness LDPE with 0.5 Al2O3 and 0.5 SiC, while the lowest coefficient of friction was noticed under normal load of 10 N, which was approximately 12.5% for the same composition. The novel approach of incorporating low fraction hybrid ceramic nanoparticles as reinforcement for LDPE matrix is investigated, highlighting their positive contributions to the tribological and mechanical properties of the resulting nanocomposites. [ABSTRACT FROM AUTHOR]

The efficient utilization of rice waste has the potential to significantly contribute to environmental sustainability by minimizing the waste impact on the environment. Through repurposing such waste, novel materials can be developed for various biomedical applications. This approach not only mitigates waste, but it also promotes the adoption of sustainable materials within the industry. In this research, rice-straw-derived nanofibers (RSNFs) were utilized as a reinforcement material for high-density polyethylene (HDPE). The rice-straw-derived nanofibers were incorporated at different concentrations (1, 2, 3, and 4 wt.%) into the HDPE. The composites were fabricated using twin-screw extrusion (to ensure homogenous distribution) and the injection-molding process (to crease the test samples). Then, the mechanical strengths and frictional performances of the bio-composites were assessed. Different characterization techniques were utilized to investigate the morphology of the RSNFs. Thermal analyses (TGA/DTG/DSC), the contact angle, and XRD were utilized to study the performances of the HDPE/RSNF composites. The study findings demonstrated that the addition of RSNFs as a reinforcement to the HDPE improved the hydrophilicity, strength, hardness, and wear resistance of the proposed bio-composites. [ABSTRACT FROM AUTHOR]