Bio-diesel as an alternative fuel for diesel engines—A review

The present review aims to study the prospects and opportunities of introducing vegetable oils and their derivatives as fuel in diesel engines. In our country the ratio of diesel to gasoline fuel is 7:1, depicting a highly skewed situation. Thus, it is necessary to replace fossil diesel fuel by alternative fuels. Vegetable oils present a very promising scenario of functioning as alternative fuels to fossil diesel fuel. The properties of these oils can be compared favorably with the characteristics required for internal combustion engine fuels. Fuel-related properties are reviewed and compared with those of conventional diesel fuel. Peak pressure development, heat release rate analysis, and vibration analysis of the engine are discussed in relation with the use of bio-diesel and conventional diesel fuel. Optimization of alkali-catalyzed transesterification of Pungamia pinnata oil for the production of bio-diesel is discussed. Use of bio-diesel in a conventional diesel engine results in substantial reduction in unburned hydrocarbon (UBHC), carbon monoxide (CO), particulate matters (PM) emission and oxide of nitrogen. The suitability of injection timing for diesel engine operation with vegetable oils and its blends, environmental considerations are discussed. Teardown analysis of bio-diesel B20-operated vehicle are also discussed.     

Large eddy simulation of forced ignition of an annular bluff-body burner

The optimization of the ignition process is a crucial issue in the design of many combustion systems. Large eddy simulation (LES) of a conical shaped bluff-body turbulent nonpremixed burner has been performed to study the impact of spark location on ignition success. This burner was experimentally investigated by Ahmed et al. [Combust. Flame 151 (2007) 366–385]. The present work focuses on the case without swirl, for which detailed measurements are available. First, cold-flow measurements of velocities and mixture fractions are compared with their LES counterparts, to assess the prediction capabilities of simulations in terms of flow and turbulent mixing. Time histories of velocities and mixture fractions are recorded at selected spots, to probe the resolved probability density function (pdf) of flow variables, in an attempt to reproduce, from the knowledge of LES-resolved instantaneous flow conditions, the experimentally observed reasons for success or failure of spark ignition. A flammability map is also constructed from the resolved mixture fraction pdf and compared with its experimental counterpart. LES of forced ignition is then performed using flamelet fully detailed tabulated chemistry combined with presumed pdfs. Various scenarios of flame kernel development are analyzed and correlated with typical flow conditions observed in this burner. The correlations between, velocities and mixture fraction values at the sparking time and the success or failure of ignition, are then further discussed and analyzed.     

Biodiesel production from two stage esterification of simarouba glauca seed oil and its characterization

In this work, biodiesel was produced from simarouba glauca seed oil through a two-stage acid-alkali esterification process. Concentrated sulphuric acid and sodium hydroxide were used as catalysts for acid and alkaline catalyzed esterification process, respectively. The free fatty acid content of the oil was reduced from 3.5 to 0.2%. The major properties of oil and its biodiesel were studied. Upon two-stage esterification, kinematic viscosity was reduced from 45.75 to 3.1 cSt and the acid value was reduced from 6.9348 to 0.4 mg KOH/g. The measured physio-chemical properties are within the limits set by ASTM biodiesel standards.     

Bio-oil extraction and physicochemical characterization of Caesalpinia pulcherrima plant seed oil

Dwarf Poinciana (Caesalpinia pulcherrima) seeds are studied for first time for the extraction of bio-oil. The dried and crushed seeds are optimized for maximum yield of bio-oil with a series of polar and nonpolar solvents and recovered by a simple distillation process. Methanol is found to yield the maximum bio-oil. The fatty acid analysis of bio-oil reveals the prevalence of linoleic acid (54.67%), followed by palmitic acid (16.9%), stearic acid (12.5%), and oleic acid (10.32%). Basic fuel properties like specific gravity, viscosity, refractive index, iodine value, saponification value, fire point, flash point, pour point, and calorific value are studied.     

Leveraging resources in global software development

Leveraging global resources for software development is rapidly becoming the norm at Motorola, which has over 25 software development centers worldwide. Our project, called the 3G Trial (Third Generation Cellular System), was the first of its scope and significance developed by a global engineering team at Motorola. Staffing was the most significant issue we encountered in the 3G Trial. We had only about 20 percent of the required staff available at our division headquarters in Burlington Heights, Ill., US, and needed to find the other 80 percent to successfully complete the project. Early on, we concluded that our only means to staff the project was to rely on software development engineers from Motorola's worldwide software centers. We developed the system with staffing from six different countries. Next, we had to integrate the people into a team. While addressing this challenge, we identified key risk factors and developed approaches to reduce them. We separated the project risk factors into the five categories Carmel (1999) describes as the centrifugal forces that pull global projects apart. To pass on the lessons we learned from this project, this article sets out the global development issues we faced, our approaches to resolving them, and our findings compared to other research     

Total sugar content in sorghum stalks and grains of selected cultivars from the world germplasm collection

Seventy sorghum cultivars from the world germplasm collection maintained at the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) were screened for total sugar content of the stalks. The total sugar content in stalks harvested after physiological maturity ranged from 17.8 to 40.3% on dry weight basis. The total sugar content in grains of 15 selected cultivars ranged from 1.02 to 2.23%. Nine cultivars having more than 34% total sugar content in stalks showed consistency for sugar content when grown for two seasons. Juiciness of stalks from five cultivars as estimated by the quantity of juice extracted varied from 266 to 464 ml per kilogram of fresh stalks. The total sugar content in the juice of five cultivars varied from 7.0 to 15.9%.     

Processing high-temperature refractory-metal silicide in-situ composites

High-temperature, refractory-metal, intermetallic, in-situ composites consist of high-strength, niobium-based silicides with a niobium-based metallic toughening phase. A variety of processing schemes have been used to generate these in-situ composites, including solidification and vapor phase processes. Secondary processing, such as forging and extrusion, has also been employed. These composites offer an excellent balance of high-and low-temperature mechanical properties with promising environmental resistance at temperatures above 1,100°C. Authors’ Note: All compositions are given in atom percent. For more information, contact B.P. Bewlay, General Electric Company, Corporate Research and Development, Schenectady, New York 12301; (518) 387-6121; fax (518) 387-5576.     

Investigations on nucleation thermodynamical parameters of NdBa2Cu3O7-δ (Nd123) crystallization by high temperature solution growth

Investigations on nucleation thermodynamical parameters are very essential for the successful growth of good quality single crystals from high temperature solution. A theoretical estimation of the nucleation thermodynamical parameters like interfacial energy between the solid Nd123 and its flux BaO-CuO, metastable zone-width, Gibbs free energy, critical energy barrier for nucleation and critical nucleation radius have been calculated from the knowledge of solubility data and by applying the classical nucleation theory. Results are discussed to understand the growth kinetics of Nd123 crystals. Paper presented at the 5th IUMRS ICA98, October 1998, Bangalore