Laser Cutting of Kevlar and Mild Steel Composite Structure: End Product Quality Assessment

In the present study laser cutting of composite structure, consisting of Kevlar laminate at the top and mild steel sheet at the bottom, is considered. The end product quality is assessed using the thermal cutting standards. To compare the end product quality of composite structure cuts, Kevlar laminate and mild steel sheet are cut using the same cutting parameters. The kerf widths for Kevlar laminate and mild steel sheet cuts are predicted from the analytical formulation based on the lump parameter analysis. It is found that the end product quality of composite structure cuts is lower than that corresponding to Kevlar laminate and mild steel sheet cuts.     

The Role of Biomass in Greenhouse Gas Mitigation

Abstract

Biomass can play a dual role in greenhouse gas mitigation related to the objectives of the UNFCCC, i.e., as an energy source to substitute for fossil fuels and as a carbon store. However, compared to the maintenance and enhancement of carbon sinks and reservoirs, it appears that the use of biomass has so far received less attention as a means of mitigating climate change. Modern biomass options offer significant, cost-effective and perpetual opportunities toward meeting emission reduction targets while providing additional ancillary benefits. Moreover, via the sustainable use of the accumulated carbon, biomass has the potential for resolving some of the critical issues surrounding long-term maintenance of biotic carbon stocks. In the case of Turkey, energy consumption and environmental pollution are increasing rapidly due to its economic growth. As for the energy consumption, in parallel to the demand for heat and electricity, greenhouse gas emissions (GHGs) from energy use increase accordingly. In this regard, biomass and other renewables are becoming an attractive solution to the GHG mitigation for Turkey and other countries throughout the world. Finally, wood products can act as substitutes for more energy-intensive products, can constitute carbon sinks, and can be used as biofuels at the end of their lifetime.     

Market penetration of fuel cell vehicles – Analysis based on agent behaviour

This paper discusses the market penetration of fuel cell vehicles (FCVs) in Germany from the perspectives of different stakeholders. There are several economic studies and models describing the introduction of hydrogen-powered vehicles, but most of them focus on only one segment of the car market. Most studies analyse the impacts of FCVs on the automotive industry or the demand for FCVs separately, while others look at the required hydrogen infrastructure, but none of these analyses examines the car market as a whole. The analysis takes into account the actions of the whole market (consumers, automotive manufacturers, filling station owners and policymakers) and their interactions.     

Conjugate heat transfer characterization in cooling channels

Cooling technology of gas turbine blades,primarily ensured via internal forced convection,is aimed towards withdrawing thermal energy from the airfoil.To promote heat exchange,the walls of internal cooling passages are lined with repeated geometrical flow disturbance elements and surface non-uniformities.Raising the heat transfer at the expense of increased pressure loss;the goal is to obtain the highest possible cooling effectiveness at the lowest possible pressure drop penalty.The cooling channel heat transfer problem involves convection in the fluid domain and conduction in the solid.This coupled behavior is known as conjugate heat transfer.This experimental study models the effects of conduction coupling on convective heat transfer by applying iso-heat-flux boundary condition at the external side of a scaled serpentine passage.Investigations involve local temperature measurements performed by Infrared Thermography over flat and ribbed slab configurations.Nusselt number distributions along the wetted surface are obtained by means of heat flux distributions,computed from an energy balance within the metal domain.For the flat plate experiments,the effect of conjugate boundary condition on heat transfer is estimated to be in the order of 3%.In the ribbed channel case,the normalized Nusselt number distributions are compared with the basic flow features.Contrasting the findings with other conjugate and convective iso-heat-flux literature,a high degree of overall correlation is evident.     

Spirulina platensis feeding inhibited the anemia- and leucopenia-induced lead and cadmium in rats

In the present investigation, the effect of Spirulina platensis (Sp) was undertaken on rats fed with lead and cadmium including diet by using physiological, enzymehistochemical and stereological methods. For this aim, 50 rats were equally divided into five groups as control (C), lead (Pb), Spirulina+lead (Sp+Pb), cadmium (Cd), and Spirulina+cadmium (Sp+Cd). Red blood cell (RBC) and white blood cell (WBC) counts, packed cell volume (PCV), and haemoglobine (Hb) concentrations were determined by haemocytometric methods in blood samples collected on 30th day. Population of T lymphocyte was counted by the alpha-naphthyl acetate esterase (ANAE) staining method, and reticulocytes were counted by stereological method. The counts of RBC, WBC, and ANAE positive T lymphocyte, and the values of Hb, PCV, and MCHC were decreased in the Pb and Cd groups compared to control group. Also, the number of reticulocytes (polychromatofilic erythrocyte) increased in the Pb groups, whereas it decreased in the Cd group. On the other hand, these values were ceased by S. platensis in the treated groups. These results suggest that S. platensis supplementation may be useful in adjuvant treatment of leukemia and anemia caused by lead and cadmium toxication.     

Deformation created by the impact of small angular and spherical particles on individual grains

Damage mechanism induced by 25 m, average size, angular and spherical particles impacting the surface of Cu-30% Zn (-brass) was investigated. Particles were impacted to the surface at normal incidence, with a velocity of 12 m/s. The primary characterization tools used were scanning electron microscopy (SEM) and atomic force microscopy (AFM). AFM allowed for the measurement of impact profiles, those of the cut surface and material pile-ups. Deformed volume by the particles was limited to a single grain. The impacts produced were asymmetrical and the chip formation was also highly directional. These asymmetries were the same in a single grain but they varied from grain to grain. Regardless of particle geometry, similar deformation features were observed on the target surface impacted by angular and spherical particles. The direction of the deformation appeared to be imposed by the mechanical response of the deforming grain. Since the deformation induced by a single impact is limited to a single grain, anisotropic mechanical properties of the individual grains observed were attributed to their impact damage morphology.     

PVA:Nano-eggshell microcomposite as an energy storage material for supercapacitors

Journal of Materials Science: Materials in Electronics - The development and advantages of wearable flexible electronics have become attractive issues with excellent electrochemical performances in...     

On modelling of surface tension of CMC-α-Fe2O3 nanoparticles by fuzzy-hybrid approach: A comparison study

Surface tension is one of the most important rheological parameters of nanoliquids. It influences the thermophysical and mass transfer properties of nanostructures. Accurate estimation of the surface tension from operating variables is critical for determining optimal production processes. However, the challenges of producing nanoparticles and measuring their properties introduce experimental errors in the data used for mathematical modelling. Crisp regression approaches provide adequate representation of the data, but they do not provide information about the experimental uncertainty. In this study, a fuzzy-hybrid approach is proposed for mathematical modelling of surface tension of carboxymethyl cellulose/chitosan-α-Fe₂O₃ nanoparticles. Then, the proposed model is compared with a crisp model from a previous study. Error analysis is conducted to validate the constructed fuzzy model. It is observed that the fuzzy-hybrid modelling approach has yielded significantly lower error values (a 60%–90% improvement in all error metrics on average), and thus, it is superior to the crisp approach. This study contributes to the subject of modelling rheological properties. It is shown that the fuzzy-hybrid approach has impressive potential to be utilized for modelling the rheological properties of nanostructures.