Abstract

The thorium fusion fission hybrid is discussed as a sustainable longer term larger resource base to the fast breeder fission reactor concept. In addition, it offers a manageable waste disposal process, burning of the produced actinides and serious nonproliferation characteristics. With the present day availability of fissile U235 and Pu239, and available fusion and accelerator neutron sources, a new look at the thorium-U233 fuel cycle is warranted. The use of the thorium cycle in a fusion fission hybrid could bypass the stage of fourth generation breeder reactors in that the energy multiplication in the fission part allows the satisfaction of energy breakeven and the Lawson condition in magnetic and inertial fusion reactor designs. This allows for the incremental development of the technology for the eventual introduction of a pure fusion technology. The nuclear performance of a fusion-fission hybrid reactor having a molten salt composed of Na-Th-F-Be as the blanket fertile material and operating with a catalyzed Deuterium-Deuterium (DD) plasma is compared to a system with a Li-Th-F-Be salt operating with a Deuterium-Tritium (DT) plasma. In a reactor with a 42-cm thick salt blanket followed by a 40-cm thick graphite reflector, the catalyzed DD system exhibits a fissile nuclide production rate of 0.88 Th(n,?) reactions per fusion source neutron.  The DT system, in addition to breeding tritium from lithium for the DT reaction yields 0.74 Th(n,?) breeding reactions per fusion source neutron. Both approaches provide substantial energy amplification through the fusion-fission coupling process. Such an alternative sustainable paradigm or architecture would provide the possibility of a well optimized fusion-fission thorium hybrid using a molten salt coolant for sustainable long term fuel availability with the added advantages of higher temperatures thermal efficiency for process heat production, proliferation resistance and minimized waste disposal characteristics.

Abstract

As an answer to a possible future situation of unchecked global climatic change involving global warming, we discuss a mitigating geoengineering project that would lead to a more stable climate for the Earth; achieved by restoring the previous stable condition in the Earth’s climate where the ancient equatorial ocean current circulated freely across the Central American Land Bridge.

Such a large scale civil engineering project would involve the conventional and nuclear excavation of a sea-level canal through several possible routes. We present the historical perspective of the Panama Canal and discuss the costs involved, previous studies of a sea-level canal across the Isthmus of Panama and its foreseen environmental consequences.

Other proposed approaches of carbon management and sequestration such as iron and iron sulfate seeding of the oceans and Earth shading are compared to the excavation approach; which appears to offer lower cost, scalable technology and is free of possible ecological unintended consequences.

Abstract

This paper presents a reliability analysis of a continuous casting (CC) steel plant. The CC plant under consideration is operating round the clock. Two years breakdown data of a CC plant for four critical equipments viz. ladle handling crane 01, 02 and billet handling crane 01, 02 have been used for the purpose. Any one equipment failure brings the CC plant to a complete halt and stops the production. The critical equipment fails due to any one of the five types of failure as categorized in the data. The paper outlines the complete reliability analysis of the plant and measures of system effectiveness such as the busy period of repairman for all types of repair, replacement, reconditioning and reinstallation, expected number of replacements, expected number of reconditioning and reinstallation, are obtained by using semi-Markov processes, and regenerative point techniques. Total profit incurred to the system is also evaluated. Related graphs are plotted to interpret the results.

Abstract

Active vibration control, which is presently one of the major research areas, is useful for aerospace structure for the increasing demand of lightweight structural design. In the present experimental study a wing like irregular structure is considered for active vibration control. The optimal locations of piezoelectric actuator and sensor are found by comparing the modal strain energy at different locations of the structure. With a single input single output (SISO) configuration of best actuator and sensor location, 90.8% vibration reduction is achieved for first mode vibration. Also the effectiveness of other actuator and sensor locations are assayed.

Abstract

Aluminium-Silicon Carbide composites are rapidly gaining importance because of their potential to produce components that features low density while maintaining high stiffness, strength, thermal stability, improved fatigue properties and wear resistance. The presence of hard SiC particles in these materials presents considerable difficulties when machining these materials resulting in rapid tool wear. Machining of these composites depends on the relative content of the reinforcement and the matrix material as well as on its response to the machining process. In this context an attempt is made here to study the influence of graphite particulates added to Al-SiC composites on tool wear. Experimental investigations have been carried out on the machinability aspects of Aluminium hybrid composites reinforced with Graphite and Silicon Carbide particulates. Machinability is expressed in terms of average flank wear caused during machining. Turning tests were carried out on Aluminium-Silicon Carbide-Graphite composite specimens to determine the tool wear on carbide inserts. It is found that the presence of graphite particulates reduces the average flank wear.

Abstract

More commonly considered criteria for judging the machinability are the cutting forces on the tool and power consumption. A classical Merchant’s model is widely used to predict the cutting forces while machining isotropic material. However no such model exists to predict the cutting forces while machining orthotropic materials. In this paper an effort is made to modify the Merchant’s formula by incorporating the K-factor to evaluate the shear strength, the fiber orientation as shear angle and a constant coefficient of friction. The cutting forces evaluated by modified Merchant’s model on unidirectional GFRP composite material has been compared with the results predicted by two-dimensional FEA model. In FEA model both maximum stress and Tsai-Hill failure criteria were used to simulate the chip separation. The influence of composite design, in particular the fiber proportion and orientation on cutting forces has been investigated. The higher fiber proportion of the composite results in increased cutting forces. Fiber angles 450 and 600 have shown favorable results. The predicted principal cutting forces by FEA agree well with the results evaluated by modified Merchant’s model.

Abstract

Experimental studies have been conducted to obtain the low speed characteristics of hypersonic vehicle configuration with two different sweep back angle. The vehicle configuration consists of blunt nose, variable sweep back wing, curved fore body Six component force and moment data were obtained over an angle of attack range from —15 to +15 degrees on the 1: 50 scale model in the wind tunnel. The sweep back angles are also changed for different test conditions. The experimental results are presented in terms of lift coefficients Drag coefficients and L/D ratio for various angles of attack and different flow velocities. It is found that there is positive lift coefficient for the configuration at zero angle of attack with considerable drag reduction due to the variable sweepback wings and produces high L/D ratio.

Abstract

The use of SCC in actual construction is still less in India. Lack of awareness, Technical data could be cited as the main reasons. For adoption of any new material or technology, it is generally needs proven performance over traditional materials. Considerable research is carried out in India towards the technology development so that SCC could soon find a place in the Indian Construction Industry. Its technical and Economical advantages are well documented and published especially through full-scale experimental casting and testing program.

In the present experimental investigation the main concentration is focused on durability properties of self compacting concrete mixes.  The number of trail mixtures are used and tests such as Slump Flow,  V-Funnel, L-box etc. are conducted for their permissible limits, then the final proportions of ingredients and admixtures have been finalized for M30, M 40, M 50 and M 60 grade concretes. Then investigations are carried out for Percentage loss in compressive strength for the specimens immersed  in H₂So₄,  HCl  and Na₂So₄ Solutions for 28, 56, 90 and 180 days and Permeability aspect.

Abstract

The modeling of engine processes continues to develop as our basic understanding of the physics and chemistry of the phenomena of interest steadily expands and as the capability of computers to solve complex equations continues to increase [1] A new generation of computer based methods has been emerged for calculating the detailed pattern of gas flow, heat transfer and combustion in reciprocating  engines by solving numerically the governing partial differential equations representing the conservation laws.

The gas motion inside the engine cylinder plays a very important role in determining the thermal efficiency of an internal combustion engine. A better understanding of in cylinder gas motion will be helpful in optimizing engine deign parameters [2].

In this paper, an attempt has been made to study the combustion processes in a compression ignition engine and simulation was done using computational fluid dynamic (CFD) code FLUENT. An Axi symmetric turbulent combustion flow with heat transfer is to be modeled for a flat piston 4-stroke diesel engine. The unsteady compressible conservation equations for mass (Continuity), axial and radial momentum, energy, species concentration equations can express the flow field and combustion in axisymmetric engine cylinder.  Modeling with variation of initial swirl ratios along with combustion was analyzed in formulating and developing a model for combustion process.

Abstract

The paper presents the results of an experimental investigation on the machinability of fabricated Aluminum metal matrix composite (A356/SiC/10p) during continuous turning of composite rods using medium grade Polycrystalline Diamond (PCD 1500) inserts. Experiments were conducted at LMW-CNC-LAL-2 production lathe at various cutting conditions and parameters such as surface roughness and tool wear were measured. The influences of cutting speed on the insert wear were studied.

An Artificial Neural Network (ANN) model has been developed for prediction of machinability parameters of MMC using feed forward back propagation algorithm. The various stages in the development of ANN models VIZ. selection of network type, input and out put of the network, arriving at a suitable network configuration, training of the network, validation of the resulting network has been taken up. A 2-9-2 feed forward neural network has been successfully trained and validated to act as a model for predicting the machining parameters of Al-SiC (10p) —MMC. The ANN models after successful training are able to predict the surface quality; tool wear for a given set of input values of cutting speed and machining time.