Papers by Keyword: Hybrid

Abstract: Maintaining safe pipeline conditions is crucial to ensure sustainable and reliable transportation for energy and water. Pipelines are generally laid underground due to larger transport capacity, rapid construction speed, space restriction, and safety precautions. Nevertheless, they are prone to failures due to mechanical problems, extreme operation, and aggressive surrounding environmental conditions. The usage of machine learning methods to predict buried pipeline failures has risen recently due to its effectiveness in addressing the aforementioned problems. This paper reviews making predictions on different buried pipeline failures by adopting machine learning approaches, particularly artificial neural networks (ANN) and hybrid methods. It highlights the detail of the machine learning algorithms as well as the parameters that were used in the predictive models with concise elaboration. Findings show that the ANN method gives accurate failure prediction, while the hybrid method enhances the prediction accuracy. Nevertheless, there is no single absolute algorithm that can work best to solve all pipeline failures. Finding the most suitable machine learning algorithm for a specific pipeline failure will be a challenge to overcome. This review is expected to give more comprehension to industry players related to machine learning methods as a potential tool to solve various buried pipeline problems. Further, this review may prompt other interested researchers to further discover machine learning potentials and ways to increase its effectiveness.

Abstract: This study examines the performance of hybrid steel-GFRP pipes compared to steel pipes, with a focus on bonding properties and the occurrence of internal corrosion. Some pipes were worn screw-shaped to mimic the effects of corrosion. The hybrid material was manufactured from two steel pipes reinforced with GFRP, bonded with polyester resin and 10% styrene to reduce viscosity and prevent bubble formation. Distortion problems during the manufacture of the specimens are addressed. Results indicate greater deformation in the worn pipes than in the steel-only specimens, whereas the hybrid material showed no significant difference between the two types. The hybrid material supported higher loads in some probes, but only two hybrid probes failed. Strain gauges measured the deformations, and the composite material's behavior was examined under a microscope. The hybrid material presented a lower flexural modulus and greater compliance to cracking. Despite the performance of the proposed hybrid material not being able to stand up to steel’s superior mechanical properties, the study offers useful insights and recommendations for future research, backed by stress-strain graphs.

Abstract: High-strength concretes made with a lot of cement and good quality aggregates added with additives and admixtures causing expensive costs. Conversely, cement manufacturing is not environment friendly due to using many natural raw materials and delivers CO₂ to atmosphere triggering global warming. Moreover, aggregates availability deriving from river reduces over time, almost 60% of civil engineering infrastructures in world are made with concrete. The purpose of this research is to study effectiveness of using cement substitute materials derived from natural geopolymer pozzolanic ash and aggregates substitute derived from palm oil mill waste in high-strength reinforced concrete beams. These local materials are abundantly available in nature but have not been used, which are utilized together to produce hybrid high-strength concrete. The test investigated was shear capacity of reinforced concrete beams in anticipating earthquake-prone areas of Indonesia. Hybrid reinforced concrete beams made with 10% pozzolanic ash as cement substitution, 20% palm oil blast furnace slag as fine aggregates substitution, and 40% palm oil shell chunks as coarse aggregates substitution. Dimensions of beams were 150 x 300 x 2200mm. To ensure shear failure emergence, beams were strengthened with longitudinal tensile reinforcement 4 D 18.9mm, longitudinal compression reinforcement 2 D 15.8mm, and shear reinforcement Ø 6 – 300 mm, resulting in capacity ratio of bending to shear 2.29. Results showed that hybrid high-strength reinforced concrete beam could reach 81.14% of shear capacity of plain beam without material substitutions, but compressive strength could significantly be increased by 130.54% and flexural tensile strength of 122.67% compared to plain high-strength concrete.

Abstract: Energy system plays an important role in the transition towards a sustainable urban life. Enhancing the quality of a livable environment through drastic reduction of pollutant emissions from fossil-fuelled generators can be achieved via the utilization of renewable energy sources. Hybrid renewable energy technologies can reliably meet the energy demands of base transceiver stations (BTS) located in off-grid rural villages. This paper aims to optimize and assess the performance of a hybrid energy system to meet the electrical load requirements of a BTS located in in Calabar, Nigeria using an off-grid hybrid system. Optimizing the control, sizing, and components of such a system aims to provide cost-effective power to these communities. The key objectives are minimizing cost of energy, total net present cost, CO2 emissions and unmet load using HOMER software. The results from the four different energy configurations were evaluated to determine the most optimized combination for the region. From the results obtained, there was a considerable variation in the optimum system configuration based on the different potential renewable energy resources. The result shows that the PV/wind/hydro/battery had a levelized cost of electricity (LCOE) as $2.40; PV/hydro/battery had $2.05; PV/wind/battery had $1.64; hydro/battery had $2.05; PV/battery had $1.38 & wind/battery had $5.44. However, due to the low wind and solar penetration in Ogoja, Nigeria, more storage systems were required for configurations without hydro component and large-scale hybrid energy systems with higher LCOE. The configuration system that showed moderate hybrid system sizes with LCOE of $1.38 was the PV/battery system with 0% energy unmet.

Abstract: In this study, the strength properties and durability of polymeric fibre-reinforced concrete containing renewable oil palm shell (ROPS) lightweight aggregate were investigated. The effect of individual Polyvinyl Alcohol (PVA) fibre, individual Polypropylene (PP) fibre and hybrid PVA-PP fibre with various percentage of volume fraction, V_f (0, 0.3 and ‘0.25+0.05’%) on the compressive strength and toughness indices of ROPS LWC were examined. The research outcomes show that compressive strength of ROPS lightweight concrete strengthened with individual PVA fibre or PP fibre enhanced with the increase of V_f fibre. From the results, toughness indices increased significantly by 38.3% compared to control mix. Furthermore, the hybrid ‘PVA0.25/PP0.05’ had revealed the optimum results as associated to other mixes. Thus, the outcomes of this paper showed that the blend of both PVA and PP polymeric fibre could potentially be utilized in concrete industry.

Abstract: Research on investigation of hybrid eco-friendly polymers modificated by humic substances are given in this article. The purpose of the research is to investigate a hybrid modification of eco-friendly polymers of polylactic acid by humic substances, it was found that the mechanism of hybrid modification in the matrix synthesis of the polylactic acid-humic substances system indicates an intermolecular bond between polylactic acid and humic substances, at the same time, due to increased crystallization and the emergence of intermolecular and ester bonds in the formation of more rigid mesh structure in the system polylactic acid-humic substances is increasing the mechanical properties of such materials. It was found that the increase in the impact strength and the breaking stress during bending in the polylactic acid-humic substances system in the hybrid modification occurs, while the optimal content of humic substances in the polylactic acid-humic substances systems is 0.5 % by mass.

Abstract: The fracture response of macro polypropylene fiber reinforced concrete (PPFRC) and hybrid blend of macro and micro polypropylene fiber reinforced concrete (HyFRC) are evaluated at 1, 3, 7 and 28 days. There is an improvement in the early-age fracture response of HyFRC compared to PPFRC. The changing cohesive stress-crack separation relationship produced by ageing of the concrete matrix is determined from the fracture test responses. An improved early-age cohesive stress response is obtained from the hybrid blend containing micro and macro fibers. The hybrid fiber blend also has a higher tensile strength at early age when compared to an identical volume fraction of macro polypropylene fibers.

Abstract: In this study, therefore, multi-walled carbon nanotubes (MWCNTs) were prepared on account of morphology, particle size and thermal properties of CNTs from high-density polyethylene (HDPE) waste and polypropylene (PP) using pyrolysis in the presence of Fe/Mn/Al catalyst. A comparison between the produced CNTs and commercially available CNTs was conducted to analyse if any deviations exist between both products. It was discovered that The commercial CNTs properties have similarities with the MWCNTs produced from plastic wastes. These materials were found to differ in purity with 1% error. The structures and morphologies of these materials are comparable as they were found to be crystalline and they revealed lattice fringes. They differ by the planes in the structural orientation. The MWCNTs synthesized from plastic wastes showed low thermal stability as opposed to the commercial CNTs.

Abstract: Mechanized arc welding is divided into two main varieties: with self-regulation of the electrode melting process and with automatic process control. The common thing between self-regulating mechanized arc welding and manual arc welding is that in the welding equipment there are no means for automatic control with feedback from the arc. The difference between them is that stabilization of the electrode melting process in mechanized welding is carried out by the source itself, which has a particular volt-ampere characteristic (CVC), by a corresponding spontaneous reaction to a change in the situation in the arc. This method is significantly inferior to the method with automatic process control in precisely maintaining the specified parameters and has a limitation on the minimum current density on the electrode. The method of pulse self-regulation of the electrode melting process proposed in the E.O.Paton EWI removes this problem. However, it requires the use of power sources with a complicated, multi-link CVC curve. Further improvement is revealed through the use of digital controlled, programmable power supplies that have an automatically generated CVC. The combination of automatic source control and self-regulation by the spontaneous reaction to the situation in the arc creates a new hybrid way to stabilize the process of arc welding with a consumable electrode and other related arc processes (surfacing, soldering, re-melting).

Abstract: Calcium-looping technology is defined as one of the most desirable methods of carbon capture, utilization and storage (CCUS). However, because of sintering, rapid deactivation of CaO-sorbents is currently a major barrier to this technology. The stability of calcium based sorbent may be enhance by incorporating them with inert support materials such as MgO, Al₂O_2, ZrO₂ and SiO₂. For this study, calcium based sorbent has been incorporate with silica obtained from rice husk ash. CaO-SiO₂ sorbents are prepared using physical dry mixing method which is much simpler compared to other available methods. The prepared CaO-SiO₂ sorbents were then characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). New crystalline phase, larnite (Ca₂SiO₄) was detected in XRD patterns and this phase possess good chemical durability and may help to prevent sintering effect of calcium based sorbents and enhance their cyclic capability. CaO-SiO₂ sorbent calcined at 700 oC with different grinding times have highest intensity of XRD peak at (104) with element of calcite. Sorbents with different weight composition of CaCO₃-RHA were observed to have different surface morphology. SEM images of the sorbent (90wt% CaCO₃-RHA) before calcination showed bigger particle size with irregular shape and more porosity. Then, SEM analysis was conducted for samples with different grinding times after calcination. CaO-SiO₂ sorbents with 20minutes grinding time exhibited small size of particles with some porosity. Besides that, the particles are well distributed without agglomeration occured. The CaO-SiO₂ sorbent calcined at 700 oC sorbents were tested for 20 consecutive carbonation and calcination cycles using Thermogravimetric Analysis (TGA). CaO-SiO₂ sorbent treated with 700 oC calcination temperature and 20 minutes of grinding shows better cyclic CO₂ sorption capacity.