Radiation and slip effects on MHD Maxwell nanofluid flow over an inclined surface with chemical reaction

The numerical solutions of the upper-convected Maxwell (UCM) nanofluid flow under the magnetic field effects over an inclined stretching sheet has been worked out. This model has the tendency to elaborate on the characteristics of “relaxation time” for the fluid flow. Special consideration has been given to the impact of nonlinear velocity slip, thermal radiation and heat generation. To study the heat transfer, the modified Fourier and Fick's laws are incorporated in the modeling process. The mass transfer phenomenon is investigated under the effects of chemical reaction, Brownian motion and thermophoresis. With the aid of the similarity transformations, the governing equations in the ordinary differential form are determined and then solved through the MATLAB's package “bvp4c” numerically. This study also brings into the spotlight such crucial physical parameters, which are inevitable for describing the flow and heat transfer behavior. This has been done through graphs and tables with as much precision and exactitude as is possible. The ascending values of the magnetic parameter, the Maxwell parameter and the angle of the inclined stretching sheet cause decay in the dimensionless velocity while an assisting behavior of the thermal and concentration buoyancy parameters is noticed.     

Understanding consumer resistance to the consumption of organic food. A study of ethical consumption,purchasing, and choice behaviour

Although the demand for organic food is growing globally, the mainstream consumption of organic food is far less. The present study attempts to understand the underlying reasons for consumer resistance toward consuming organic food using the theoretical framework of innovation resistance theory (IRT). The study further examines the association between different consumer barriers and purchase decisions (purchase intentions, ethical consumption intentions, and choice behaviour) at different levels of buying involvement and environmental concerns. The collected data, consisting of 452 consumers, were analyzed by structural equation modeling approach. The results showed that value barrier shared a negative association with purchase intentions and ethical consumption intentions. Ethical consumption and purchase intention were found to have a direct influence on choice behaviour. Additionally, the relationship between ethical consumption intention and choice behaviour is mediated by purchase intention. However, no significant differences have emerged based on the level of buying involvement and environment concerns. The findings of the study provide insight into public policymakers, marketers, suppliers, and consumer associations by enhancing their current understanding of buying behaviour of the growing organic food community.     

Preparation and desalination performance of porous planar cordierite membranes using industrial solid waste as main silica source

Silica is a main component of cordierite ceramic, in the present work, industrial solid waste was used as main silica source to prepare porous planar cordierite membranes by a solid-phase sintering process with starch as pore-forming agent. It is shown that the concentration of starch plays a critical role in the pore structure and mechanical property and the cordierite membranes with a starch concentration of 40?wt% (M-40) have a desirable pore structure and flexural strength after sintering at 1300?°C for 5?h. After grafted with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (FAS, C₈), the ceramic membranes were used for desalination by vacuum membrane distillation (VMD). The results show that the membranes(M-40) possess an average flux of 11.43?kg/m² h, a high salt rejection of 99.9% under the following operation conditions: a NaCl concentration of 3.5?wt%, a feed rate of 300?ml/min and a temperature of 80?°C. After desalination for 120?h, the water contact angle decreases to 130°. The cordierite membranes exhibit poor resistance to thermal acid/alkali solution(boiling, pH?=?1 and 14, respectively, soaked for 8?h) but excellent resistance to ambient temperature acid/alkali solution (25?°C, pH?=?1 and 14, respectively, soaked for 120?h).     

Fire hazard in transportation infrastructure: Review,assessment, and mitigation strategies

This paper reviews the fire problem in critical transportation infrastructures such as bridges and tunnels. The magnitude of the fire problem is illustrated, and the recent increase in fire problems in bridges and tunnels is highlighted. Recent research undertaken to address fire problems in transportation structures is reviewed, as well as critical factors governing the performance of those structures. Furthermore, key strategies recommended for mitigating fire hazards in bridges and tunnels are presented, and their applicability to practical situations is demonstrated through a practical case study. Furthermore, research needs and emerging trends for enhancing the “state-of-the-art” in this area are discussed.     

Corrosion of Li-ion battery cathode materials on mullite insulation materials during calcination

A specially designed experimental device was used in laboratory to investigate the corrosion of mullite during the calcination of Li(Ni_xCo_yMn_z)O₂ (LNCM) materials. The anti-corrosion tests were carried out at 1000, 1100, 1200 and 1300 °C, and characterized with X-ray diffraction and scanning electron microscopy. The influence of temperature on the interactions between mullite insulation materials and LNCM materials was determined. In addition, the high-temperature creep properties of the mullite insulation materials before and after corrosion were tested. The laboratory scale tests, thermodynamic and kinetic calculations allowed a more comprehensive understanding of the evolution of the mullite insulation materials during serving for the roasting process of LNCM materials. Through this research, it is suggested that the upgrading of the kiln lining in the lithium battery industry should select materials with excellent resistance to alkali corrosion, especially excellent resistance to Li⁺ corrosion.     

Improvement in the properties of low carbon MgO-C refractories through the addition of graphite-SiC micro-composite

Graphite–SiC micro-composites have been prepared in–house by carbothermal reduction process. Controlling the process parameters including the weight ratio of SiO₂ to graphite as well as carbothermal reduction temperature during the micro-composite preparation favors the homogeneous formation of SiC with preferred morphologies like ribbons and whiskers/fibers. The micro-composite modified low carbon MgO-C refractories have exhibited significantly improved bulk properties over the standard composition. To understand the beneficial role of SiC reinforcement on hot strength performance under air oxidizing conditions, we propose a scaling parameter known as strength factor (fs) based on the ratio of hot strength (HMOR) to cold strength (CCS). Correlating the strength factor data (fs) with oxidative damage provides new insights into the reinforcing effects of distinct SiC morphologies in this new class of micro-composite fortified refractory systems over the standard compositions.     

Characterization of anisotropic gas permeability and thermomechanical properties of highly textured porous alumina

Porous alumina with a highly textured microstructure was fabricated by pulse electric current sintering (PECS) using alumina platelets. Highly oriented porous alumina with a porosity of 3%–50% was obtained by a pressure-controlled method of PECS. The properties of the highly textured porous alumina were measured in two directions. The nitrogen gas permeance and thermal conductivity at room temperature were higher in the direction along the platelet length due to the higher continuity of pores and the connectivity of alumina platelets, respectively. The anisotropy of the thermal conductivity at room temperature was investigated and explained by the effect of grain size of platelets as well as morphology and orientation of pores. The bending strength was higher with the loading direction along the platelet thickness. The thermal shock strength was clearly different in the two directions. The difference in the thermal shock strength was investigated by the measurement of properties and thermal stress analysis.     

Application of Cr3C2/C composite powders synthesized via molten-salt method in low-carbon MgO–C refractories

High-performance and low-carbon MgO–C refractories are important refractories for smelting ultra-low carbon steel and clean steel. Based on this, Cr₃C₂/C composite powders were synthesized by the molten-salt method, and used as an additive to prepare low-carbon MgO–C refractories under nitrogen atmosphere. The phase, morphology and oxidation kinetics of Cr₃C₂/C composite powders were studied. In addition, the effect of Cr₃C₂/C composite powders on the morphology, mechanical properties, thermal shock resistance, and corrosion resistance of MgO–C refractories was investigated. The results indicated that the Cr₃C₂/C composite powders exhibited superior oxidation resistance than flake graphite. Moreover, the Cr₃C₂/C composite powders were introduced into the MgO–C refractories. Compared with the sample without Cr₃C₂/C composite powders, the introduction of 1 wt% Cr₃C₂/C composite powders significantly improved the thermomechanical properties and corrosion resistance of the material, its CMOR, CCS before and CCS after thermal shock were 9.06 MPa, 50.40 MPa and 32.60 MPa, respectively, and the corrosion index was significantly reduced from 44.6% to 26.5%.     

A comparative study on the effect of carbon-based and ceramic additives on the properties of fiber reinforced polymer matrix composites for high temperature applications

Ablative composites have been in use for thermal protection of space vehicles for decades. Carbon-phenolic composites have proven to perform exceptionally well in these applications. However with development in aerospace industry their performance needs improvement. In this field, different carbon-based and ceramic additives have been introduced into ablative composite systems. This review article gives a comparative analysis of researches done in this field in the recent past. Density, ablative, thermal and mechanical properties of ablative composites with different ultra-high temperature ceramic particles i.e. ZrSi₂, Cenosphere, nano-SiO₂, BN etc. and carbon-based nanoparticles i.e. CNTs, nano-Diamonds, Graphene oxide etc. used as additives, have been compared and discussed. Emphasis is put on carbon-phenolic composite systems although some epoxy matrix systems have also been discussed for comparison.