Generalized Magneto-thermoelastic Interaction in a Fiber-Reinforced Anisotropic Hollow Cylinder

In this article, an estimation is made to investigate the transient phenomena in the magneto-thermoelastic model in the context of the Lord and Shulman theory in a perfectly conducting medium. A finite element method is proposed to analyze the problem and obtain numerical solutions for the displacement, temperature, and radial and hoop stresses. The boundary conditions for the mechanical and Maxwell’s stresses at the internal and outer surfaces are considered. An application of a hollow cylinder is investigated where the inner surface is traction free and subjected to thermal shock, while the outer surface is traction free and thermally isolated. The displacement, incremental temperature, and the stress components are obtained and then presented graphically. Finally, the effects of the presence and absence of reinforcement on the temperature, stress, and displacement are studied.     

Thermomechanical Analysis of (Cu0.5Tl0.5)-1223 Substituted by Pr and La

The thermomechanical analysis (TMA) of Cu 0.5 Tl 0.5 Ba 2 Ca 2 x R x Cu 3 O 10 δ,where R=Pr and La,with 0.0≤x≤0.15,was carried out in temperature range from 450 to 1145 K.The samples were prepared by singlestep solid state reaction technique.The prepared samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).The superconductivity of the prepared samples was investigated by electrical resistivity measurement.The results showed that low substitution content enhanced the (Cu 0.5 Tl 0.5)1223 phase formation,while the higher substitution content degraded this phase.The higher superconducting transition temperatures T c were found to be 114 K and 109 K at x= 0.025 for Pr-and La-substitutions,respectively.The average linear thermal expansion coefficient increased as x increased,while the shrinkage temperature decreased as x increased.Those results were emphasized by porosity and Vickers microhardness calculations.Debye temperature θ D was calculated from the linear thermal expansion coefficient data and correlated to T c to estimate the electron-phonon coupling λ ep.     

The effects of Ni3Al binder content on the electrochemical response of melt-infiltration processed TiC–Ni3Al cermets

TiC–Ni₃Al samples were successfully fabricated with varying amounts of the Ni₃Al intermetallic binder (alloy IC-50), ranging from 10 to 40?wt-%, through a simple melt-infiltration method. Each sample was then tested to determine the degree of resistance of that composition to electrochemical corrosion in an aqueous solution containing 3.5?wt-% NaCl, using a range of testing procedures including open-circuit potential, potentiodynamic polarisation and cyclic polarisation. Results indicate that the lowest binder content results in greater potential to resist corrosion. It is demonstrated that the Ni₃Al binder undergoes dissolution for the examined conditions, which was confirmed through the high amount of Al and Ni in the electrolyte solutions following testing. It was also confirmed from the electrochemical experiments and the SEM that localised corrosion was visible.     

Prioritizing HAZOP analysis using analytic hierarchy process (AHP)

Hazard and operability (HAZOP) analysis is one of the most widely used methods for process hazard analysis. However, the outcome of HAZOP analysis could result in identifying large number of hazards, thus posing a challenge for assessors to take actions in dealing with all the hazards. The common practice in prioritizing the critical hazards is based on assessors’ experience through deductive judgment using rating scale, taking into consideration safety and the associated costs. Although being simple and straightforward, HAZOP has the disadvantage of lacking systematic approach to elucidate different conclusions into an integrated outcome, thus susceptible to inaccurate and unjustified decisions. In this paper, we present a structured methodology for incorporating prioritization in HAZOP analysis using analytic hierarchy process. Through this approach, the hazards of a process identified using HAZOP will be quantitatively weighted and ranked based on their priority along with the appropriate counter measures to be taken. The proposed methodology is a thorough decision-making tool as it does not only prioritize the hazards identified from the HAZOP assessment, but also provides medium for the assessors to quantitatively analyze the hazards. To show its efficacy, the approach will be applied to a simple reactor unit and a more complex system of dividing wall column pilot plant as case studies. The result shows that the proposed methodology is capable of identifying and ranking the most significant hazards in a process following HAZOP analysis. This is particularly useful, especially to process designers/engineers in prioritizing their efforts and resources on more significant hazards, hence aiding toward achieving an inherently safer chemical process.     

Ni/Pd-promoted Al2O3–La2O3 catalyst for hydrogen production from polyethylene terephthalate waste via steam reforming

Ni/Pd-co-promoted Al₂O₃–La₂O₃ catalysts for selective hydrogen production from polyethylene terephthalate (PET) plastic waste via steam reforming process has been investigated. The catalysts were prepared by impregnation method and were characterized using XRD, BET, TPD-CO₂, TPR-H₂, SEM, TGA and DTA. The results showed that Ni-Pd-co-impregnated Al₂O₃–La₂O₃ catalyst has excellent activity for the production of hydrogen with a prolong stability. The feed conversion of 87% was achieved over 10% Ni/Al₂O₃ catalyst which increased to 93.87% in the case of 10% Ni-1% Pd/Al₂O₃–La₂O₃ catalysts with an H₂ fraction of 0.60. The catalyst performance in term of H₂ selectivity and feed conversion was further investigated under various operating parameters, e.g., temperatures, feed flow rates, feed ratios and PET concentrations. It was found that the temperature has positive effects on H₂ selectivity and conversion, yet feed flow rate has the adverse effects. In addition, PET concentrations showed improved in H₂ selectivity in comparison to when only phenol as a solvent was involved. The Ni particles, which are the noble-based active species are more effective, thus offered good hydrogen production in the PET steam reforming process. Incorporation of La₂O₃ as support and Pd as a promoter to the Ni/Al₂O₃ catalyst significantly increased catalyst stability. The Ni–Pd/Al₂O₃–Al₂O₃ catalyst showed remarkable activity even after 36 h along with the production of carbon nanotubes, while H₂ selectivity and feed conversion was only slightly decreased.     

Innovation in hydrogen production

In this study, the critical perspectives of innovation are introduced for specifically for hydrogen production under a new concept (so-called: 18S concept), covering source, system, service, scope, staff, scale-up, safety, scheme, sector, solution, stakeholder, standardization, subsidy, stimulation, structure, strategy, support and sustainability. The roles of these specific conceptual items are discussed, and their importance is highlighted. Furthermore, the innovative methods in hydrogen production are assessed by using a ranking method for comparison and evaluation purposes. The results show that renewable sources, particularly hydro, geothermal and solar show a unique potential to support these innovative H₂ production systems. When the H₂ production systems are compared, the ones supporting heat recovery (thermal) and the photonic based options show better performance in terms of emissions, cost and efficiency.     

Performance improvement study of an integrated photovoltaic system for offshore power production

Sustainable energy is one of the main options for resolving energy problems and climate change issues. Solar energy is one of the main promising renewable energy sources, which can be captured and converted to electrical energy through photovoltaic (PV) panels. In the open literature, it is shown that having two PV panels integrated into a back‐to‐back configuration placed on naturally reflective surfaces provides the potential of doubling the total power produced by a single‐faced PV panel with the appropriate location and orientation. This paper presents a case study of two‐PV panel systems for offshore power production. The relevance to offshore has the water surface as the reflective surface to produce power from the back facing panel. The city of Ottawa in Canada is selected as the location for a case study. Various conditions and operating parameters are considered in assessing the performance of the proposed system, including solar radiation intensity, system orientation, time of year in terms of months, and the variations in parameters throughout the day. The assessment of the proposed system is carried out through modeling and simulating the proposed double PV panels in the COMSOL Multiphysics software. It is found that the minimum improvement in the total power production over the single face conventional PV is 38% in January for the east‐facing PV front face. For the two PV systems, the optimal overall power production for the various time conditions and orientations, at the specified location, is found to be the north orientation of the PV panel. In this case, the power it produces is 89% of that of the east orientation. A similar trend is observed for the single‐faced PV panel, where the north‐facing PV provides 62% of what it could produce in the east‐facing orientation.     

Evaluation of a new geothermal based multigenerational plant with primary outputs of hydrogen and ammonia

Increasing environmental concerns and decreasing fossil fuel sources compel engineers and scientists to find resilient, clean, and inexpensive alternative energy options Recently, the usage of renewable power resources has risen, while the efficiency improvement studies have continued. To improve the efficiency of the plants, it is of great significance to recover and use the waste heat to generate other useful products. In this paper, a novel integrated energy plant utilizing a geothermal resource to produce hydrogen, ammonia, power, fresh water, hot water, heated air for drying, heating, and cooling is designed. Hydrogen, as an energy carrier, has become an attractive choice for energy systems in recent years due to its features like high energy content, clean, bountiful supply, non-toxic and high efficiency. Furthermore in this study, hydrogen beside electricity is selected to produce and stored in a hydrogen storage tank, and some amount of hydrogen is mixed with nitrogen to compound ammonia. In order to determine the irreversibilities occurring within the system and plant performance, energy and exergy analyses are then performed accordingly. In the design of the plant, each sub-system is integrated in a sensible manner, and the streams connecting sub-systems are enumerated. Then thermodynamic balance equations, in terms of mass, energy, entropy and exergy, are introduced for each unit of the plant. Based on the system inputs and outputs, the energy and exergy efficiencies of the entire integrated plant is found to be 58.68% and 54.73% with the base parameters. The second part of the analysis contains some parametric studies to reveal how some system parameters, which are the reference temperature, geothermal resource temperature and mass flow rate, and separator inlet pressure in the geothermal cycle, affect both energy and exergy efficiencies and hence the useful outputs.