The basics of antifriction coatings is to lower the frictional response of a surface. The coated material should either lower the interfacial shearing or increase stiffness of the surface. The latter should be reached by using carbon nano-fillers embedded in a polymer matrix. We choose PMMA as a matrix. The objective of this study is to gain knowledge on the influence of carbon nano-fillers on the surface response of PMMA nano-composites.

The mechanical properties and wear behavior of Dual Phase (DP) steels have been investigated and compared with those observed in normalized (N) steel that has the same chemical composition. The DP steels having different content and morphology of martensite were produced by varying intercritical annealing temperature and initial microstructures. Mechanical properties of four different DP steels and N steel have been investigated by carrying out tensile and macrohardness tests. Dry sliding wear tests have been conducted on four different the DP steels and the N steel using pin-on-plate to investigate their wear characteristics. It has been found that the yield and tensile strengths and macrohardness increase with increasing martensite content and decreasing martensite size. The yield and tensile strengths and macrohardness of the N steel were significantly lower than the DP steels whereas percentage of total elongation was higher. Wear properties are improved by increasing martensite volume fraction and size in the DP steels. The N steel specimen showed the highest wear rate.

Ventilation is part of the acceptable indoor air quality and thermal comfort problem. Carbon monoxide (CO) is a highly toxic gas that’s emitted from cars in vehicular spaces. A new strategy of ventilation called periodic supply exhaust strategy is used. The main advantage of PRESEV strategy is reducing air flow rate requirement and also achieve averaged CO ppm rise according to standards. With the PRESEV strategy a ventilation flow rate 27% of that required by conventional piston or mixed ventilation strategies could achieve the same maximum hourly averaged local CO ppm rise. This paper aims at applying the PRESEV strategy throughout different cases and check effectiveness on these cases.

Global warming and depletion of fossil fuels have compelled the researchers to study the sources of renewable energy. Biogas, one of the most promising alternative renewable biofuel, is produced from anaerobic digestion. It mainly consists of methane and carbon dioxide (CO 2 ) with traces of water vapor, hydrogen sulfide (H 2 S), siloxanes, hydrocarbons, ammonia, oxygen, carbon monoxide and nitrogen. The presence of high concentration of CO 2 in biogas lowers the energy content per unit mass/volume. This limits its utility to only low quality energy applications where as H 2 S is a highly toxic and corrosive gas. Therefore, it is extremely difficult to transport and store biogas. Thus, the need emerges for a unified approach for scrubbing, compression and subsequent storage of biogas for wider applications. The current work presents the scrubbing of biogas using the method of adsorption. The quality of the scrubbed biogas studied by gas chromatography is presented. The scrubbed biogas is then tested in a dual fuel diesel engine as a primary fuel to evaluate the performance and emission characteristics of the engine. The data obtained are compared with those of raw biogas run dual fuel diesel engine.

The diesel engine is widely used for marine vessel propulsion due to its relatively high efficiency compared to existing alternative propulsion systems. The majority of these engines are slow speed two stroke ones. Despite the improvement of their efficiency there now exists a demand for drastic reduction of daily fuel oil consumption as a result of the global financial situation and continuously increasing fuel prices. Towards this effort, slow steaming is a promising solution for the drastic reduction of daily and specific fuel consumption when expressed in tn/mile. This requires engine operation in the low load (low speed) range where these engines are not designed to operate for long term. The main problem related to slow-steaming, is the lack of air which has a negative impact on the engine and its subsystems. A promising solution to the problem is turbocharger (T/C) cut-out at low load when more than one T/C exists. In the present work a combined computational and experimental investigation is conducted to evaluate the operation potential of a large two stroke marine diesel engine equipped with two T/Cs using T/C cut-out, for which the specific technology presents various challenges. This is achieved using an in-house engine simulation model and measurements with and without T/C cut-out. From the results it is revealed that using this technique the scavenging air and peak firing pressure increase while the specific fuel consumption decreases. In this way, some major problems related with the long term operation of the engine under low load conditions, i.e. accumulation of carbon deposits on the exhaust gas side and continuous operation of the auxiliary air blowers, are surpassed. Moreover, a theoretical investigation is conducted considering fuel injection retard to minimize the peak firing pressure penalty while taking care to limit the corresponding negative impact on specific fuel consumption. For NOx emissions the effect of T/C cut-out is also considered using tail pipe emission data measured during the official shop tests. From the analysis conducted it has been revealed that the technique of turbocharger cut–out (one of two) is technically feasible and could offer certain advantages when slow-steaming is implemented. Moreover, comparing the calculated with the measured results, it has been revealed that the simulation model successfully estimates engine operation with and without T/C cut-out, being a valuable tool for the engineers to investigate combustion and pollutant formation mechanisms under various engine configurations.

Development of IC engines with low emissions and low fuel consumption causes interest in direct injection engine, especially diesel engines that work with lean mixture. This goal may be achieved with separation of mixture formation and combustion processes, in diesel engines. A practicable way to reach this target is the use of porous medium (PM) inside the combustion chamber. The PM has benefits to enhance the evaporation of droplets in liquid-fuel burners, reduce emissions and minimize instabilities. This paper represents the numerical study of liquid-fuel injection and combustion inside constant-volume chemically inert PM to stabilize lean mixture. 3D numerical results have obtained based on a modified version of KIVA-3V code. Diesel was directly sprayed inside hot and high pressure PM chamber. Complete evaporation and self-ignited was achieved due to the initial temperature of PM. The results in an especial condition have compared with an experimental data in the literature. Effect of injection in cold condition has investigated. Contours of diesel vapor, fluid and solid temperature of PM in a cross section, have shown. Also, effects of pore density on a constant high-porosity PM and mass of spray fuel were studied. The results show considerable reduction in carbon monoxide, nitrogen monoxide and elimination of soot.

Carbon Black (CB) and carbon nanotubes (CNTs) are both nano-scale forms of graphitic carbon (CB presents itself as nano-spheres of carbon). Both have excellent electrical, thermal and mechanical properties, what why they are often used in composite fabrication.

In roads building, classical asphalt mix manufacturing commonly requires the heating (at 160°C) and the complete drying of aggregates. The induced energy cost has opened the way to develop alternatives processes and materials with low energy/carbon materials such as Warm Mix Asphalt (WMA). In warm mixes processes, aggregates manufacturing temperatures are different and lower than the Hot Mix ones. However, manufacturing temperature reduction can locally lead to poor bonding between bitumen and aggregate during the mixing step, due to the bitumen viscosity increasing, although bonding quality measurement remained a challenge. The aim of our study was to presents two thermal inverse methods for bonding quality assessment. These methods are based on Thermal Contact Resistance (TCR) assessment between bitumen and aggregate, during asphalt mix manufacturing. The experimental test principle consisted of heating both bitumen and cylindrical aggregate to their manufacturing temperatures (over 100°C) and to put them into contact thanks to a special experimental device. According to initial samples temperatures, heat transfer occurs from the bitumen to the aggregate. Two variants of the sequential Beck’s method were used to solve the inverse heat conduction problem. The first one consisted of determining the TCR from heat flux and temperatures and the second one consisted of identifying directly the TCR. The TCR values were interpreted as bonding quality criteria. Results showed low sensitivity to temperature measurement noise in the second variant of the inverse method. Moreover our study showed that bonding quality depends on bitumen and aggregate temperatures. The higher the component’s temperatures, the lower the TCR values and better is the bonding quality.

The work developed in this paper is realized within the ecoDriver EU FP7 project that is shortly presented in the first part of the paper. Among the several main objectives underlined by this project, one consists in developing a vehicle and energy consumption model to be validated and then used to help the driver to better drive in terms of consumption and safety, advised by a HMI (Human-Machine Interface) module. Several experimental results are shown to illustrate the obtained energy saving with such an EDAS and the legal speed respect.

In this paper, nonlinear vibration characteristics of a viscoelastic microplate under electrostatic actuation have been obtained. The microplate has been assumed as a CNT-reinforced simply supported square plate and an electrostatic actuation applied on it. The nonlinear equations of motion have been derived and solved, by using combined Galerkin method and indeterminate coefficient procedure. Static pull-in instability of the microplate has been also derived. It has been shown that the pull-in voltage, natural frequency and deflection of the system depend on the value of electrostatic actuation and viscoelastic characteristics of the microplate and differ from those obtained in elastic one. So, good selection of composite components (nanotube, base matrix) can result in better controlling of the microplate due to increasing/decreasing of the pull-in voltage.

Fabric reinforced or textile composites are increasingly used in aerospace, automotive, naval and other applications. They are convenient material forms providing adequate stiffness and strength in many structures. In such applications they are subjected to three-dimensional states of stress coupled with hydro-thermal effects. Assuming that a composite material is a complex structure it is obvious that is hard to describe all its properties in terms of its parts properties. The properties of the composite depend not only on the properties of the components but on quality and nature of the interface between the components and its properties. As reinforcement two types of fiber fabric were used; first one is a simple type fabric of untwisted tows of carbon filaments while the second one is also simple type but as yarn and fill are used alternately untwisted tows of carbon and aramide filaments. There were some problems to be solved before molding: fabric stability during handling, cutting, imbuing the carbon and aramide tows are slipping one on each other leading to fabric defects; generally the epoxy systems do not adhere to the carbon fiber; in order to obtain a valuable material the nature of interface must be the same for polymer-carbon fiber and polymer aramide fiber. In order to solve these problems the two fabrics were covered (by spraying) with a thin film of PNB rubber. Into the rubber solution were also dispersed small amounts of clay (to create a better interface) and carbon black (to improve the electrical conductivity). The rubber presence solves the fabric stability problem; ensures the same type of interface between fibers and polymer matrix; ensures a more elastic interface between fibers and polymer matrix. This treatment induces modification on tensile behavior of fabrics. This study is about mechanical evaluation of such fabrics.

Among composites, the polymer matrix ones are the cheapest and the easiest to form but they show major disadvantages such as poor electrical and thermal conductivity, low fire resistance etc. In the case of any composite, some of the properties may be designed, some of them may be obtained by using an appropriate forming technique and, at least, some of them may be improved by special treatments. In the case of polymer matrix composites the first two ways are recommended if we are taking into account the polymers’ properties while the last one will turn the PMC into an expensive material due to the costs of metal or oxide thin film deposition on polymeric surface. Is it possible to solve all the problems by material design and by developing a convenient forming technique? Powders are used as fillers in order to obtain bi-components composites. The most important aim is about the uniform distribution of particles in matrix. If the fillers’ particles are arranged into the polymer volume is possible to change the electro-magnetic behavior of the obtained composite making this one to act as a meta-material. The powders can be dielectric as talc, clay or ferrite can be magnetic active as ferrite, or electric active as CNT or carbon nano-fibers. All these powders have effects on the electromagnetic, thermal and mechanical properties of the composite. This study is about the influence of fillers on the tribological behavior of particulate composites. Epoxy resin was used as matrix and various powders were used to fill the polymer: ferrite, zinc, clay. The materials were thermally treated in order to reach the best polymer properties. Pin on disk fixture on a CETR-UTM had been used to determine the friction coefficient for each filler concentration. The Wear resistance of each material had been evaluated using the same apparatus but with some modifications.

Performance and exhaust emission studies of Waste Chicken Oil Methyl Ester (WCOME)-diesel fuel blends has been presented in this paper. The production of biodiesel from waste chicken oil was carried out via transesterification method. Blending ratios were preferred as 5% (B5), 10% (B10), 25% (B25) and 50% (B50) respectively. Performance and emission studies were carried out in a commercial diesel engine. The performance results reveal that blends of WCOME with diesel fuel provide increase on the brake specific fuel consumption (bsfc) and decrease on the brake power output proportional to the reduction in the heating value of blends. As a result, while the carbon monoxide (CO) and the carbon dioxide (CO2) emissions were reduced, nitrogen oxides (NOx) emissions were stated higher compared with the diesel fuel emission characteristics.

The multi-component composites could represent the cheapest solution when controllable properties are required. In order to establish the right amount of filler it is necessary to analyze not only the electro-magnetic and mechanical properties but also, the thermal ones. The filler presence in the matrix produces discontinuities at the fibre-matrix interface with consequences regarding mechanical properties. Using a single filler it is possible to improve one or two properties electrical and thermal conductivity for instance and mean time to induce a decrease of other properties as bending strength, shock resistance etc. Using polymer layers with relatively high electrical conductivity as external layers of laminate and magnetic particles filled polymer as core layers. An electric circuit might be, at the same time, the reinforcement of a composite leading to lighter structures and, based on carbon fiber’s properties might transmit information about the material’s loading, temperature or integrity. Fabric reinforced or textile composites are used in aerospace, automotive, naval and other applications. They are convenient material forms providing adequate stiffness and strength in many structures. The microstructure of composite reinforced with woven, braided, or stitched networks is significantly different from that of tape based laminates. The properties of the composite depend not only on the properties of the components but on quality and nature of the interface between the components and its properties. Reinforced composites with filled epoxy matrix were formed using a hybrid technique consisting in layer-by-layer adding of reinforcement sheets into a glass mould. Various distributions of reinforcement sheets and filled polymer layers were realized in order to point out the ways in which the final properties might be controlled. Mechanical properties were analyzed.

This paper presents an analysis of several 3D parameters based on bearing area curve in order to use the information for establishing the influence of sliding regime against steel on the tribological behavior of a composite class with polyamide matrix and 1% of black carbon. There were done pin-on-disk tests for different concentrations of micro glass spheres (MGS): 2.5, 5, 10, 20, 30 and 50% (wt), respectively. The polymer was tested under similar conditions in order to have a reference basis and to point out the improvement in tribological behavior when adding this reinforcement material. The surface topographies were registered with the help of PRO500 3D (stylus) Profilometer. The test parameters in dry regime were: sliding speed 0.5, 1.0 and 1.5 m/s, average pressure 1, 2 and 3 MPa, respectively. There were analyzed the influence of MGS concentration and sliding regime on wear as mass loss of the composite discs, after 10,000 m of sliding, the friction coefficient and several 3D parameters related to the bearing area curve, determined from raw profiles (surface bearing index – Sbi, core fluid retention index – Sci, valley fluid retention index, Svi, reduced summit height, Spk, core roughness depth, Sk, and reduced valley depth, Svk).

In this study, mode I fatigue crack growth behavior of single edge notched thin aluminum plates repaired with single side composite patches is investigated experimentally. Three patches are investigated in this analysis, 1- three layers carbon/epoxy laminated composite patch, 2- smart patches contained shape memory alloy (SMA) wires without pre-strain embedded in between the carbon/epoxy layers, and 3- smart patches contained SMA wires with pre-strain embedded in between the carbon/epoxy layers. The results are compared with the results obtained for un-repaired notched plate and the influence of SMA wires is also studied. The experimental results show a significant increase in crack growth life in all repaired plates compared with un-repaired plate. The repaired plates with smart pre-strained SMA patches show greater life as compared to other plates repaired by other patches. The three layers carbon/epoxy patches show better results compared to smart SMA un-strained patches. Also, numerical modeling is done by ANSYS software to obtain the stress intensity factor in mode I fatigue loading and then applied to Paris law for prediction of the fatigue crack growth life. The results are compared with the experimental results and a good agreement is obtained.

Increasing the thermal efficiency of fossil fuel fired power plants in general and the gas turbine power plant in particular is of extreme importance. In the face of diminishing natural resources and increasing carbon emissions that lead to a heightened greenhouse effect and greater concerns over global warming, thermal efficiency is more critical today than ever before. In the science of thermodynamics, the best yardstick for a power generation system’s performance is the Carnot efficiency — the ultimate efficiency limit, set by the second law, which can be achieved only by a perfect heat engine operating in a cycle. As a fact of nature this upper theoretical limit is out of reach, thus engineers usually set their eyes on more realistic goals. For the longest time, the key performance benchmark of a combined cycle (CC) power plant has been the 60% net electric efficiency. Land-based gas turbines based on the classic Brayton cycle with constant pressure heat addition represent the pinnacle of fossil fuel burning power generation engineering. Advances in the last few decades, mainly driven by the increase in cycle maximum temperatures, which in turn are made possible by technology breakthroughs in hot gas path materials, coating and cooling technologies, pushed the power plant efficiencies to nearly 40% in simple cycle and nearly 60% in combined cycle configurations. To surpass the limitations imposed by available materials and other design considerations and to facilitate a significant improvement in the thermal efficiency of advanced Brayton cycle gas turbine power plants necessitate a rethinking of the basic thermodynamic cycle. The current paper highlights the key thermodynamic considerations that make the constant volume heat addition a viable candidate in this respect. First using fundamental air-standard cycle formulas and then more realistic but simple models, potential efficiency improvement in simple and combined cycle configurations is investigated. Existing and past research activities are summarized to illustrate the technologies that can transform the basic thermodynamics into a reality via mechanically and economically feasible products.

Atomistic models of polyaniline (PANI)-single walled carbon nanotubes (CNTs) were built in order to assess the effect of quantity and quality of CNTs and temperature on the calculated mechanical properties of PANI. Three different types of CNTs were considered: single walled carbon nanotubes m-polyaminobenzene sulfonic acid functionalized (CNTs-PABS), single walled carbon nanotubes octadecylamine functionalized (CNTs-ODA) and single walled carbon nanotubes carboxylic acid functionalized (CNTs-CX). Atomistic models were built for PANI-functionalized CNTs with a range of CNTs content, contained within periodic boundary conditions and were subject of multistage equilibration procedure. In order to test the mechanical behaviour of the models virtual uniaxial traction tests along the three perpendicular edges of the models were performed. The Young’s moduli generally increased with increasing of CNTs content and values range from 0.48 GPa in the case of pure PANI to 1.35–1.83 GPa in the case of PANI-CNTs-PABS composite system.

This paper demonstrates a comparison of product recovery methods, by carbon footprint calculation, for repaired products with remanufactured products and the environmental impact that they have when they reach their end-of-life (EOL). Growing concerns of climate change and government legislation have changed the way in which consumers can dispose of used or broken products. Items can no longer be sent to landfill and it is now the responsibility of the producers to dispose of products in a more sustainable manner and take into consideration all stages of the products life cycle. A standardised method for calculating carbon footprints has been used and a carbon footprint carried out for each product recovery method. Specific data was collected, from a manufacturing company in England’s North West region, about the processes involved during each recovery method and have identified that repairing has a lower carbon footprint than remanufacturing. However, repairing only extends the existing life cycle of a product, whereas remanufacturing can be carried out up to three times, and provides the product with a new life cycle. Therefore, remanufacturing is seen as the most preferable method of product recovery in terms of carbon emissions and sustainable waste disposal.

This research focuses on elucidating on the processing-structure-property relationship in hierarchically-structured polymer composites that are being developed for multifunctional structures. This is accomplished through characterization of the transition in mechanical behavior that occurs across length scales and compositions by: (a) development of model hierarchically-structured composite materials using a combination of model nanoscale and microscale ingredients (carbon nanofibers (CNFs) and carbon microfibers (CMFs)) reinforcing a High Impact Polystyrene (HIPS) thermoplastic polymer that can be extruded or solvent processed, (b) characterization and modeling of the transition compositions in the polymer nanocomposites through melt rheology, and (c) the effect of the CNF on the dynamic compressive behavior of CMF-reinforced polymer composites.