The effect of triacetin as a fuel additive to waste cooking biodiesel on engine performance and exhaust emissions

This study investigates the effect of oxygenated fuels on engine performance and exhaust emission under a custom cycle using a fully instrumented 6-cylinder turbocharged diesel engine with a common railinjection system. A range of oxygenated fuels based on waste cooking biodiesel with triacetin as an oxygenated additive were studied. The oxygen ratio was used instead of the equivalence ratio, or air to fuelratio, to better explain the phenomena observed during combustion. It was found that the increased oxygen ratio was associated with an increase in the friction mean effective pressure, brake specific fuel consumption, CO, HC and PN. On the other hand, mechanical efficiency, brake thermal efficiency, CO2, NOx and PM decreased with oxygen ratio. Increasing the oxygen content of the fuel was associated with a decrease in indicated power, brake power, indicated mean effective pressure, brake mean effective pressure, friction power, blow-by, CO2, CO (at higher loads), HC, PM and PN. On the other hand, the brakespecific fuel consumption, brake thermal efficiency and NOx increased by using the oxygenated fuels. Also, by increasing the oxygen content, the accumulation mode count median diameter moved toward the smaller particle sizes. In addition to the oxygen content of fuel, the other physical and chemical properties of the fuels were used to interpret the behavior of the engine.

Unexpected effect of tetraglyme plasticizer on lithium ion dynamics in PAMPS based ionomers

Li(+) cation conducting ionomers based on poly(2-acrylamido-2-methyl-1-propane sulphonic acid) (PAMPS) incorporating a low molecular weight plasticizer have been characterized. Previously we have observed an apparent decoupling of ionic conductivity and lithium ion dynamics from the Tg of this ionomer along with an increase in ionic conductivity obtained by incorporating a quaternary ammonium co-cation. The incorporation of tetraglyme as a coordinating plasticizer was investigated in order to further improve the ion dissociation and dynamics. Solid-state NMR, thermal analysis, impedance spectroscopy and infrared spectroscopy were used to characterize these systems. As expected, the glass transition temperature Tg decreased upon the addition of the plasticizer. However, in contrast to the previously reported Na-conducting systems, the ionic conductivity was also decreased by several orders of magnitude, indicating that the tetraglyme recouples the conductivity back to the polymer dynamics. Temperature dependent (7)Li NMR line width and T1 measurements were used to probe the Li(+) dynamics, which were found to be dependent on the Li(+) concentration, the nature of the co-cation and the presence or absence of tetraglyme.

Miscibility, UV resistance, thermal degradation, and mechanical properties of PMMA/SAN blends and their composites with MWCNTs

Poly(methyl methacrylate)/poly(styrene-co-acrylonitrile) (PMMA/SAN) blends, with varying concentrations, were prepared by melt-mixing technique. The miscibility is ensured by fixing the acrylonitrile (AN) content of styrene acrylonitrile (SAN) as 25% by weight. The blends were transparent as well. The Fourier transform infrared spectroscopic (FTIR) studies did not reveal any specific interactions, supporting the well accepted 'copolymer repulsion effect' as the driving mechanism for miscibility. Addition of SAN increased the stability of PMMA towards ultraviolet (UV) radiations and thermal degradation. Incorporation of even 0.05% by weight of multi-walled carbon nanotubes (MWCNTs) significantly improved the UV absorbance and thermal stability. Moreover, the composites exhibited good strength and modulus. However, at higher concentrations of MWCNTs (0.5 and 1% by weight) the thermo-mechanical properties experienced deterioration, mainly due to the agglomeration of MWCNTs. It was observed that composites with 0.05% by weight of finely dispersed and well distributed MWCNTs provided excellent protection in most extreme climatic conditions. Thus, PMMA/SAN/MWCNTs composites can act as excellent light screens and may be useful, as cost-effective UV absorbers, in the outdoor applications.

Rapidly cured epoxy/anhydride composites: effect of residual stress on laminate shear strength

The drive towards rapid cure thermosetting composites requires a better understanding of the residual stresses that develop during curing. This study investigates the impact of residual stresses on the interlaminar shear strength of resin-infused epoxy/anhydride carbon-fibre laminates. The magnitude of the residual stress was varied by changing the initial injection cure temperature between 75 °C and 145 °C. The corresponding cycle times and the final glass transition temperature of the resin were also measured. The experimentally measured chemical shrinkage and thermal expansion properties of the resin after vitrification were used as inputs to a finite element analysis to calculate the peak residual stresses in the composite. An increase in the initial cure temperature from 85 to 135 °C resulted in an increase of 25% in the residual stress, which led to an experimentally measured reduction in the composite's short beam shear strength of approximately 16% (8 MPa), in good agreement with model prediction.

Parametric study on thermal performance of horizontal earth pipe cooling system in summer

Rational use of energy and its associated greenhouse gas emissions has become a key issue for a sustainable environment and economy. A substantial amount of energy is consumed by today's buildings which are accountable for about 40% of the global energy consumption. There are on-going researches in order to overcome these and find new techniques through energy efficient measures. Passive air cooling of earth pipe cooling technique is one of those which can save energy in buildings with no greenhouse gas emissions. The performance of the earth pipe cooling system is mainly affected by the parameters, namely air velocity, pipe length, pipe diameter, pipe material, and pipe depth. This paper investigates the impact of these parameters on thermal performance of the horizontal earth pipe cooling system in a hot humid subtropical climate at Rockhampton, Australia. For the parametric investigation, a thermal model was developed for the horizontal earth pipe cooling system using the simulation program, FLUENT 15.0. Results showed a significant effect for air velocity, pipe length, and pipe diameter on the earth pipe cooling performance, where the pipe length dominated the other parameters.

One-way water-transport cotton fabrics with enhanced cooling effect

Two types of directional water transport fabrics are prepared by using cotton fabric as substrate and an electrospraying technique to apply a hydrophobic coating on one side of the fabric. The main difference between the two electrosprayed fabrics is that one of them was precoated with a hydrophilic thermoconductive resin over the fiber surface prior to electrospraying. As a result, the precoated fabric has a much higher thermoconductivity than the other, while they are similar in water transport and fibrous structure. In the wet state, the directional water-transport fabrics generate a temperature difference between the two fabric sides while drying naturally. The fabric with higher thermal conductivity shows smaller temperature difference, better thermal transfer within the fabric, stronger evaporation cooling effect, and accelerated moisture evaporation. Directional water transport fabrics with high thermal conductivity may be used to mitigate thermal burden in sportswear, summer clothing, medical fabrics, and workwear.

Dynamic mechanical-thermal, microstructural and mechanical analysis of ultra-light polymer-metal composites: influence of forming

A really particular and innovative metal-polymer sandwich material is Hybrix. Hybrix is a product developed and manufactured by Lamera AB, Gothenburg, Sweden. This innovative hybrid material is composed by two relatively thin metal layers if compared to the core thickness. The most used metals are aluminum and stainless steel and are separated by a core of nylon fibres oriented perpendicularly to the metal plates. The core is then completed by adhesive layers applied at the PA66-metal interface that once cured maintain the nylon fibres in position. This special material is very light and formable. Moreover Hybrix, depending on the specific metal which is used, can achieve a good corrosion resistance and it can be cut and punched easily. Hybrix architecture itself provides extremely good bending stiffness, damping properties, insulation capability, etc., which again, of course, change in magnitude depending in the metal alloy which is used, its thickness and core thickness. For these reasons nowadays it shows potential for all the applications which have the above mentioned characteristic as a requirement. Finally Hybrix can be processed with tools used in regular metal sheet industry and can be handled as solid metal sheets. In this master thesis project, pre-formed parts of Hybrix were studied and characterized. Previous work on Hybrix was focused on analyze its market potential and different adhesive to be used in the core. All the tests were carried out on flat unformed specimens. However, in order to have a complete description of this material also the effect of the forming process must be taken into account. Thus the main activities of the present master thesis are the following: Dynamic Mechanical-Thermal Analysis (DMTA) on unformed Hybrix samples of different thickness and on pre-strained Hybrix samples, pure epoxy adhesive samples analysis and finally moisture effects evaluation on Hybrix composite structure.

Temperature dependence of the electrode potential of a cobalt-based redox couple in ionic liquid electrolytes for thermal energy harvesting

Increasing the application of technologies for harvesting waste heat could make a significant contribution to sustainable energy production. Thermoelectrochemical cells are one such emerging technology, where the thermal response of a redox couple in an electrolyte is used to generate a potential difference across a cell when a temperature gradient exists. The unique physical properties of ionic liquids make them ideal for application as electrolytes in these devices. One of the keys to utilizing these media in efficient thermoelectrochemical cells is achieving high Seebeck coefficients, Se: the thermodynamic quantity that determines the magnitude of the voltage achieved per unit temperature difference. Here, we report the Se and cell performance of a cobalt-based redox couple in a range of different ionic liquids, to investigate the influence of the nature of the IL on the thermodynamics and cell performance of the redox system. The results reported include the highest Se to-date for an IL-based electrolyte. The effect of diluting the different ILs with propylene carbonate is also reported, which results in a significant increase in the output powers and current densities of the device.

Solar and thermal radiative effects during the 2011 extreme desert dust episode over Portugal

This paper analyses the influence of the extreme Saharan desert dust (DD) event on shortwave (SW) and longwave (LW) radiation at the EARLINET/AERONET Évora station (Southern Portugal) from 4 up to 7 April 2011. There was also some cloud occurrence in the period. In this context, it is essential to quantify the effect of cloud presence on aerosol radiative forcing. A radiative transfer model was initialized with aerosol optical properties, cloud vertical properties and meteorological atmospheric vertical profiles. The intercomparison between the instantaneous TOA shortwave and longwave fluxes derived using CERES and those calculated using SBDART, which was fed with aerosol extinction coefficients derived from the CALIPSO and lidar-PAOLI observations, varying OPAC dataset parameters, was reasonably acceptable within the standard deviations. The dust aerosol type that yields the best fit was found to be the mineral accumulation mode. Therefore, SBDART model constrained with the CERES observations can be used to reliably determine aerosol radiative forcing and heating rates. Aerosol radiative forcings and heating rates were derived in the SW (ARFSw, AHRSw) and LW (ARFLw, AHRLw) spectral ranges, considering a cloud-aerosol free reference atmosphere. We found that AOD at 440 nm increased by a factor of 5 on 6 April with respect to the lower dust load on 4 April. It was responsible by a strong cooling radiative effect pointed out by the ARFSw value (−99 W/m2 for a solar zenith angle of 60°) offset by a warming radiative effect according to ARFLw value (+21.9 W/m2) at the surface. Overall, about 24% and 12% of the dust solar radiative cooling effect is compensated by its longwave warming effect at the surface and at the top of the atmosphere, respectively. Hence, larger aerosol loads could enhance the response between the absorption and re-emission processes increasing the ARFLw with respect to those associated with moderate and low aerosol loads. The unprecedented results derived from this work complement the findings in other regions on the modifications of radiative energy budget by the dust aerosols, which could have relevant influences on the regional climate and will be topics for future investigations.

Effect of heat stress on milk production of goats from Alpine and Saanen breeds in Brazil.

The purpose of this bibliography review was to approach the thermal comfort rates on milk production of goats from Alpine and Saanen breeds in Brazil. The caloric stress caused by weather changes to which the animals are submitted, influence on the mechanisms of normal physiological processes of the body. Thus, the effect on the lactation process in goats can be mentioned, where it decreases the amount of water in the body with the consequent decrease in synthesis and milk ejection interfering in the production of hormone prolactin and growth hormone. The animal?s interaction with the environment must be considered when the aim in livestock farming is welfare, because the different responses of the animal to the peculiarities of each region are crucial for the success of the animal adaptation. So, the correct identification of the factors that influence the productive life of the animal, such as the stress caused by the seasonal fluctuations of the environment, allow production systems management, making it possible to make them sustainable and viable. The maintenance of these parameters in normal levels is very important, to the point of being used in the evaluation of climate adaptability of breeds to a certain environmental condition. In this way, the concerns about animal welfare and environmental comfort are due to the climatic variables and the behavioral, physiological and productive responses are prevailing when implementing the suitability of certain production systems.

Effect of acid alcoholic solution in waxy maize starch treatment.

O amido é o polissacarídeo mais abundante presente em plantas, composto por amilose e amilopectina. O amido de milho ceroso apresenta somente amilopectina. A modificação do amido é recomendada para melhorar suas aplicações. A hidrólise ácida é utilizada para alterar as propriedades físico-químicas sem modificar o grânulo e o meio alcoólico ajuda na recuperação da molécula após o tratamento. O objetivo do trabalho foi o tratamento químico com HCl 0,5 mol L-1 durante 1 hora em 100 ml de água, etanol ou metanol. Os equipamentos SETSYS Evolução TGADTA / DSC e Rápido Visco-Analisador (RVA-4) foram usados para avaliar as alterações dos amidos. As curvas TG mostraram três eventos (desidratação, estabilidade e decomposição), com resultados similares para todas as amostras. Este resultado pode estar relacionado a resistência da amilopectina para a hidrólise ácida. Na análise reológica (RVA) o tratamento das amostras mostrou valores mais baixos de perfis de viscosidade. A solução ácida forneceu mudanças nas propriedades de pasta do amido e a solução etanólica (solvente mais apolar) foi maior que as demais soluções. Conclui-se portanto que o tratamento dos amidos forneceu produtos com características térmicas similares e com diferentes respostas mecânicas

Effect of the KMnO4 Treatment on the "pinhão" starch.

O pinhão, sementes de Araucaria angustifolia, tem o amido como componente principal. Os amidos oxidados melhoram as características físico-química, de pasta e térmicas dos produtos em processos industriais. O amido de pinhão nativo foi tratado com soluções padronizadas de permanganato de potássio (KMnO4) e as amostras foram analisadas por técnicas termoanalíticas (TG-DTA) em atmosfera inerte. As amostras foram oxidadas da seguinte forma: quatro porções de 20 g (base seca) foram separadas e três foram suspensas em solução de KMnO4 (0,001; 0,002; 0,005 mol L-1) em agitação constante durante 30 minutos, a quarta amostra foi mantida como recebida. As suspensões de amido foram filtradas, lavadas, secas e analisadas. As modificações oxidativas provocaram mudanças estruturais das moléculas de amido, registradas pelos diferentes resultados calculados a partir das curvas TGA e DTA. A amostra (3) teve as mudanças mais significativas na degradação com o 3ª evento exotérmico com temperaturas acima de 330 °C.