Increasing urbanization and industrialization have led to a phenomenal growth in transportation demand worldwide, coupled with a concentration of vehicles in metropolitan cities. With regard to increasingly stringent emission legislation natural gas is gaining interest as a transportation fuel with worldwide over 19 million natural gas vehicles in operation. This paper presents the worldwide background, prospects and challenges of natural gas fuel and natural gas fueled vehicles along with environmental and economic aspects of compressed natural gas as a transformation fuel. Technical aspects of compressed natural gas properties, storage, safety problems and its effect on engine performance, efficiency, emissions and barriers to natural gas vehicles adaptation are discussed in detail. The main indicators selected for the comparative assessment of natural gas as vehicular fuel are: economic, emission performance and safety aspect. The results showed that CNG has several advantages over both diesel and gasoline fuel, including considerable emission and cost reductions.

Technical overview of compressed natural gas (CNG) as a transportation fuel

Experimental investigation on performance, combustion and emission analysis of a direct injection diesel engine fuelled with rapeseed oil biodiesel

One of the most significant barriers to the broad adoption of additive manufacturing (AM) is the qualification of AM produced parts. With the high market competition, quality has become the market differentiator for products and services. To maintain or enhance the quality of the products, manufacturers use two techniques, quality assurance and control. In fact, many researchers characterize the quality assurance and control as the biggest challenge to widespread adoption of AM technologies for metals parts in aerospace industries. One approach to overcome this challenge is to implement in-situ process monitoring and inspection systems to enhance the quality of the printed parts and AM processes. This has been highlighted by numerous research efforts for the past decade and continues to be identified as a high priority research in the AM processes. In this paper, we review current process monitoring and control systems for metal AM in Powder Bed Fusion and Directed Energy Deposition systems. And then, possible inspection system configurations for improving the quality of AM printed parts are discussed based on the proposed framework and requirement. A comprehensive real-time inspection method and a closed loop monitoring system are proposed to address the quality control for metal-based AM processes

Process monitoring and inspection systems in metal additive manufacturing: Status and applications

A comprehensive review of global production and recycling methods of polyolefin (PO) based products and their post-recycling applications

Corn and soybean biodiesel blends as alternative fuels for diesel engine at different injection pressures

Bio-diesel is one of the most promising alternatives for diesel needs. Use of edible oil may create shortage of oil seeds for daily food, which necessitates identification of new kinds of non-edible vegetable oil. With this objective, the present work has focused on the performance of castor non-edible vegetable oil and its blend with diesel on a single cylinder, 4 stroke, naturally aspirated, direct injection, water cooled, eddy current dynamometer Kirloskar Diesel Engine at 1500 rpm for variable loads. Initially, castor neat oil and their blends were chosen. The physical and chemical properties of Castor oil were determined. In general, viscosity of neat vegetable oil is high, which can be reduced through blending with diesel and heating them. The heating temperature of the blends increases with the increase in the percentage of neat oils with diesel ranging from 70°C to 120°C before entering into the combustion chamber. The suitability of neat Castor oil and their blends are evaluated through experimentation. The performance and emission characteristics of engine are determined using Castor neat oil and their blends with diesel. These results are compared to those of pure diesel. These results are again compared to the other results of neat oils and their blends available in the literature for validation. By analyzing the graphs, it was observed that the performance characteristics are reduced and emission characteristics are increased at the rated load compared to those of diesel. This is mainly due to lower calorific value, high viscosity and delayed combustion process. From the critical analysis of graphs, it can be observed that 25% of neat Castor oil mixed with 75% of diesel is the best suited blend for Diesel engine without heating and without any engine modifications. It is concluded that castor non-edible oil can be used as an alternate to diesel, which is of low cost. This usage of neat bio-diesel has a great impact in reducing the dependency of India on oil imports.

Performance and emission characteristics of a diesel engine with castor oil

In pulsed Nd:YAG laser welding process, the material melts and solidifies consecutively by a peak high power laser beam. The solidification time in this process is very less as compared to that of conventional welding process. The mode of welding process is governed by the process parameters like laser energy, pulse duration, pulse frequency, power and welding speed. This paper aimed at to examine the influence of welding speed and power on weld bead geometry and performance parameters such as duty cycle, pulse overlap, energy density and bead diameter. In this contest, first experiment is conducted on austenitic 304L stainless steel sheet by varying the welding speed from 2 mm/s to10 mm/s and second experiment is conducted varying laser power from 300 W to 3500 W. It was found from the experimental and analytical approach welding speed and laser power significantly affects on weld bead geometry, variation in bead diameter from pulse to pulse, duty cycle and effective pulse energy. © 2013 PEI, University of Maribor. All rights reserved.

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Influence of laser welding process parameters on weld pool geometry and duty cycle

The research on alternative fuels has become essential due to depletion of petroleum products and its major contribution for pollutants. In the present work, Compressed Natural Gas (CNG) has been introduced as an alternative fuel to overcome the above problems. Of the higher compression ratio, higher octane number, the CNG is used to allow the combustion without knocking. The emission characteristics of HC and CO are better for CNG compared to petrol. In this work experimental investigations have been carried out pertaining to the engine performance and exhaust emissions of a single cylinder 4-stroke air cooled type Bajaj-Kawasaki engine

Performance analysis of a 4-stroke SI engine using CNG as an alternative fuel

Evaluation of Nd: YAG Laser Welding Efficiencies for 304L Stainless Steel

Welding dissimilar metals and alloys is essential to emerging new technologies in manufacturing industries. This process is difficult because of the formation of intermetallic layers and the variations in the chemical and mechanical properties in the weld region. This paper aimed to characterize fully and partially penetrated dissimilar metal weld joints. The welding experiments were conducted on 0.5 mm-thick dissimilar weld joints for the investigation of the effects of the process parameters on the weld joints. Variations in chemical composition, oxide formation, imperfections and mechanical properties were analyzed. Results revealed that the weld joint characteristics notably deviated from the base metal properties in terms of hardness, strength, chemical composition, oxide formation and other constituents of the weld pool region. This study offers insight into the effects of process parameters and the necessary changes in weld composition for the improvement of welds joints.

E. Ramjee

Papers

Performance and emission characteristics of a diesel engine with castor oil

Influence of laser welding process parameters on weld pool geometry and duty cycle

Performance analysis of a 4-stroke SI engine using CNG as an alternative fuel

Evaluation of Nd: YAG Laser Welding Efficiencies for 304L Stainless Steel

Characterization of fully and partially penetrated Nd: YAG laser-weld dissimilar metal joints