Tribological properties of hydrogen free DLC in self-mated contacts against ZDDP-added oil

The tribological properties of tetrahedral diamond-like carbon (DLC) films in self-mated contacts in the presence of additivated and non-additivated vegetable oils. DLC films have high practical value due to low friction and low wear properties were evaluated. On the other hand, vegetable oils are considered to be lubricants for future due to its resource renewability and biodegradability. Sometimes different chemical agents are added to vegetable oils to further improve its tribological properties. Thus, the tribological study of DLC films against additivated oils becomes important. The tribology tests were conducted in a four ball tribo-meter under the boundary lubricated conditions. Ta-C DLC exhibited 80% lower wear rate under Zinc dialkyldithiophosphates (ZDDP)-added oil compared to that of base oil. In contrast, the friction coefficient under additivated oil was slightly higher than the base oil lubricated case. Moreover, the carbonyl band area as well as the viscosity change of ZDDP-added oil was much smaller than that of base oil. Therefore, ZDDP reduced the wear of DLC film and prevented the oxidation of base oil during tribotests

Tribological properties of steel/steel, steel/DLC and DLC/DLC contacts in the presence of biodegradable oil

Tribological properties of tetrahedral diamond-like carbon (ta-C DLC) coating were investigated to assess the effects of the counter surfaces under the boundary condition in the presence of biodegradable oil. The tribological tests were performed using steel/steel, steel/DLC and DLC/DLC contacts, and found that the coefficient of friction was 0.062, 0.059 and 0.048, and the wear loss was 5.57×10–4, 9.81×10–4 and 6.02×10–4 mm3, respectively. DLC/DLC contacts showed the lowest friction coefficient and steel/steel contacts showed the lowest wear. The high wear of steel/DLC compared to the other two contacts might be due to the high affinity between iron and carbon. The high content of oleic acid may maintain the low friction in self-mated ta-C DLC contacts and tribochemical wear was prevented by nano-scale graphitization. Therefore, material combinations are important for tribological properties and canola oil is an effective lubricant for contacts coated with ta-C DLC films

Tribological performance of DLC/DLC and steel/DLC contacts in the presence of additivated oil

In this study, the tribological properties of ta-C DLC were largely influenced by the counter surfaces and additives. The DLC/DLC contact showed approximately 60% lower wear when tested with additivated oil compared to that of base oil and this result was 66% in steel/DLC contact. Friction coefficient in DLC/DLC contact was lower than in steel/DLC contact under both oils. But however, both contacts showed slightly higher friction coefficient under additivated oil compared to that of base oil. In steel/DLC, the thermo-chemical reaction between carbon and iron and/or the fusion of the transferred particles were prevented by additives which were present under base oil. The fracture found on DLC surface in steel/DLC contact under additivated oil indicates that the tribolayer formed on the steel surface would be of brittle nature. The passivation of surfaces in DLC/DLC contact by additives prevented the damage which was observed under base oil

Production of biodiesel from a non-edible source and study of its combustion, and emission characteristics: A comparative study with B5

This investigation deals with the production of Alexandrian laurel (Calophyllum inophyllum) biodiesel (ALB) and study of the effects of its fatty acid methyl ester (FAME) compositions and physicochemical properties on the engine performance, combustion, and emissions. The experiment had been conducted in a four cylinder turbocharged diesel engine under varying speeds and full loading condition. 10% (ALB10) and 20% (ALB20) blends of Alexandrian laurel biodiesel along with the Diesel and B5 fuel (95% diesel and 5% palm biodiesel) were used for this experiment. ALB consisted of 31.6% saturated and 68.4% unsaturated FAME. Longer chain fatty acids and 10.9% oxygen content of ALB greatly influenced the engine combustion and emission characteristics. Brake specific fuel consumption (bsfc) was found on average 6%-20% higher for B5, ALB10, and ALB20 blends compared to diesel fuel. It was observed that ALB operation shortened the ignition delay period, increased the mass fraction burnt (MFB), and reduced the pick cylinder pressure, heat release rate (HRR) and combustion duration. CO and HC emissions were decreased significantly while operating on B5, ALB10, and ALB20 blends compared to diesel fuel. ALB blends produced on average, 2.5%-3% higher NOX emissions with respect to diesel fuel

Polymer electrolyte liquid crystal mixtures as phase-dependent thermoelectric materials

Organic thermoelectric materials have gained a trajectory in recent years given its advantages of processability, low cost and flexibility. In this paper, polymer electrolyte liquid crystal (PELC) mixtures composed of polyvinyl alcohol, potassium iodide, and 4-Cyano-4'-pentylbiphenyl (5CB) liquid crystal are fabricated, the 5CB acts as a ‘temperature switch’, i.e., a strong correlation between the thermoelectric properties and the transition from Ne-Iso transition of the 5CB, is observed. The electrical conductivity and Seebeck coefficient of the PELC mixtures both decrease above the Ne-Iso transition temperature. This thermoelectric behavior is discussed in terms of the carrier concentration, carrier mobility, and order-disorder transition

Technical challenges and enhancements in smart grid applications

This chapter deals with novel technologies in terms of power electronics, power converters, information and communication technologies (ICTs), energy storage systems (ESSs), electric vehicles (EVs), and microgeneration systems in the context of smart grid applications. Although the smart grid was a concept defining ICT-enabled conventional grid at the beginning, it has now improved its own infrastructure with particularly tailored applications and technologies. During this improvement stage; researchers, engineers, and technology improving alliances have overcome many technical challenges. This chapter presents a number of innovative solutions enhanced against challenges met during improvement era. They have been introduced in terms of power electronics and power converters, integration of communication systems to power devices; improved microgrid, generation and transmission systems, the demand side management (DSM) policies, smart home management systems, ESSs and EVs. The surveyed device topologies and technologies are particularly selected in order to present a set of recent application in smart grid infrastructure. Therefore, widely known devices, systems, and methods that can be found in any regular textbook are not considered in this section