A.K. Majumder

Effect of impinging angle and rotating speed on erosion behavior of aluminum

Commercial aluminum (grade 1900) in rotary motion was exposed to slurry of sand in water. Samples were mounted at various angles and rotated at different speeds. Wear rate was calculated using mass loss measurement. The results show that wear rates increase with increasing impingement angle up to 90°. Contrary to the conventional understanding of maximum loss of ductile material at about 45° impingement angle, maximum wear rate was observed in case of the aluminum sample fixed at 90°. However, increasing rotation speed of the samples results in exponential increase in wear rate. The findings are substantiated with the metallographic study of worn surface.

Modeling of Coal Flotation in a Batch and Continuous Cell Operation: Part 1—Kinetic Approach

Detailed kinetic analyses of various size fractions of coal in a batch and continuous flotation operation have been presented. It is shown that the recoveries of non-ash and ash forming materials of individual size fractions during flotation in both batch and continuous cells can be described adequately by first order kinetic equations. A methodology has been proposed to predict the kinetic parameters in continuous flotation using suitable correction factors to batch flotation data.

A knowledge based system using multiple expert modules for monitoring leprosy/spl minus/an endemic disease

An environment with multiple expert modules is essential for proper handling of diagnosis and monitoring of chronic endemic diseases. In this paper, we present LEPDIAG/spl minus/a knowledge based system for diagnosis and monitoring of leprosy. The proposed architecture is a conglomeration of three expert modules and a procedural performance evaluator. A novel feature of the architecture is inclusion of the homeostatic expert module which models the immunological reaction of the patient. The entire system provides a closed loop diagnosis and follow-up environment. LEPDIAG is built around the fuzzy expert system building tool FRUIT for dealing with imprecise knowledge. The domain knowledge in LEPDIAG is expressed by fuzzy production rules. The rules have been partitioned using suitable clustering criteria. The rule conflict is resolved using metarules. The information objects used and the fuzzy inference strategy adopted have been illustrated. >

Comparative study on magnetite medium stability in a vorsyl separator and in a heavy medium cyclone

It is reported in the literature that a Vorsyl separator (VS) performs better than a heavy medium cyclone (HMC) when treating coals with high near-gravity material. The discussions are generally based on the results of laboratory or plant-scale data treating various coals. However, no effort has been made so far to identify the reasons behind the superior performance of a VS compared to a HMC. Medium stability is an important parameter, which affects the performance of any heavy medium separator. Therefore, an attempt has been made to study the magnetite medium stability behavior inside a HMC and VS at identical operating conditions. It is found that at any fixed-operating condition, the differential between the underflow and overflow slurry density is always less in a VS than in a HMC. Possible theoretical explanations supported by experimental data have been provided to substantiate this finding.

An empirical model for chloridising-roasting of potassium in glauconitic sandstone

Abstract Chloridising-roasting followed by aqua leaching has been used to extract potassium from glauconitic sandstone. The investigation includes study of the kinetic aspects of roasting and effects of major process variables. The variables studied are time, temperature, particle size of glauconitic sandstone, and ratio of mixing of calcium chloride and glauconitic sandstone. An attempt has been made to express the reaction rate as a function of process variables through the use of the following empirical correlations: τ α=0.3−0.8 =5.43 × 10 −8 (α 2.15 ·d 1.5412 ·r −2.03 ·e 12321 T ) (a) τ α=0.9 =2.6 × 10 −8 (r −2.105 ·e2 20377.7 T ) (b) These correlations express the combined effect of different process variables on degree of conversion.

An Assessment of Malatya-Arguvan Lignite and Southeastern Anatolia Region Lignites (Turkey)

Turkish lignites are usually low in heating value and burning characteristic with high sulfur and ash content. They are unable to conform to air protection regulation requirements if burned as mined. Generally, they are used in power plants causing environmental problems. In this study, assessment possibilities of Malatya-Arguvan lignite are investigated and washability properties of Eastern and Southeastern Anatolia region lignites are discussed. For this purpose, experimental studies were performed with lignite samples taken from a lignite field in Malatya-Arguvan, Turkey. First, proximate analysis of lignite samples was made. Afterwards, washability properties of lignite samples were determined. Assessment of the washability properties was made by calculating some of the popular indices, such as index of washability, washability number, and near gravity material index, and the obtained results were presented.

A fuzzy expert system approach for real-time monitoring of endemic diseases

Abstract In this paper, an architecture of LEPDIAG—a knowledge based system for on-line diagnosis and for monitoring prognosis of leprosy—is presented. The important features of LEPDIAG that have been detailed are a multiple expert environment, a homeostatic expert containing the model of immune reaction, a performance evaluator that can compare the observed signs and symptoms with those predicted by homeostatic expert, and a prognostic expert which optimizes the management schedule for the patients. The entire system is built around a fuzzy expert system building tool FRUIT to deal with the imprecise knowledge.

Investigation of the effectiveness of desliming and flotation in cleaning Malatya-Arguvan lignite

ABSTRACT This study investigated the possibility of cleaning Malatya-Arguvan lignite using the flotation method. Because preliminary flotation studies suggested that desliming affects flotation performance, an attempt was made to quantify the effects of the major influencing parameters on the effectiveness of desliming and flotation. Because the optimum collector dosage was found to be very high, the effects of addition of sodium oleate and Aero 3477 were also investigated, to reduce the collector dosage. However, flotation results showed that the addition of sodium oleate and Aero 3477 does not alter the collector dosage significantly. Despite all the aforementioned efforts, only 20% of feed ash could be removed.

A fuzzy expert system approach using multiple experts for dynamic follow-up of endemic diseases

In this paper, an architecture oflepdiag — a knowledge-based system for on-line diagnosis and for monitoring prognosis of leprosy is presented. The important features oflepdiag that have been detailed are a multiple expert environment, a homeostatic expert containing the model of immune reaction, a performance evaluator that can compare the observed signs and symptoms with those predicted by the homeostatic expert and a prognostic expert which optimizes the management schedule for the patients. The entire systems is built around a fuzzy expert-system building toolfext to deal with the imprecise knowledge.