Sanjeev Garg

Isolation, identification and application of novel bacterial consortium TJ-1 for the decolourization of structurally different azo dyes

A novel bacterial consortium (TJ-1), which could decolorize Acid Orange 7 (AO7) and manyother azo dyes, was developed. In TJ-1 three bacterial strains were identified as Aeromonas caviae, Proteus mirabilis and Rhodococcus globerulus by 16S rRNA gene sequence analysis. AO7 decolorization was significantly higher with the use of consortium as compared to the use of individual strains, indicating complementary interactions among these strains. AO7 decolorization was observed under microaerophilic condition in the presence of organic carbon source. Either yeast extract (YE) alone or a combination of YE and glucose resulted in much higher decolorization of AO7 as compared to glucose alone, peptone or starch. Kinetic studies with different initial AO7 concentrations showed that more than 90% decolorization could be achieved even at 200mg/l within 16h. Fed-batch studies showed that AO7 decolorization required 10h during the first cycle and 5h in the second and third cycles, showing that bacterial cells could be used for multiple cycles. The consortium also decolorized fifteen other azo dyes individually as well as a simulated wastewater containing a mixture of all the sixteen azo dyes, thus, conferring the possibility of application of TJ-1 for the treatment of industrial wastewaters.

Multiobjective optimization of a free radical bulk polymerization reactor using genetic algorithm

A multiobjective optimization technique has been developed for free radical bulk polymerization reactors using genetic algorithm. The polymerization of methyl methacrylate in a batch reactor has been studied as an example. The two objective functions which are minimized are the total reaction time and the polydispersity index of the polymer product. Simultaneously, end-point constraints are incorporated to attain desired values of the monomer conversion (x m ) and the number average chain length (μ n ). A nondominated sorting genetic algorithm (NSGA) has been adapted to obtain the optimal control variable (temperature) history. It has been shown that the optimal solution converges to a unique point and no Pareto set is obtained. It has been observed that the optimal solution obtained using the NSGA for multiobjective function optimization compares very well with the solution obtained using the simple genetic algorithm (SGA) for a single objective function optimization problem, in which only the total reaction time is minimized and the two end-point constraints on x m and μ n are satisfied.

Correlation of monthly-average daily global, diffuse and beam radiation with bright sunshine hours

Abstract Correlations between monthly-average daily radiation and bright sunshine hours for 11 Indian stations have been studied. It is found that the global radiation can be predicted to an accuracy of 0.5% by using the linear relation, G/Gext = a + b (n/N). For diffuse radiation, three different correlations have been tried. For individual applications, any of the three correlations discussed in this paper can be used, but for collective applications, the correlation D/Gext = a + b (n/N) gives better results. Beam radiation is found to be highly dependent upon the local conditions. To develop a single formula for 11 stations involves a large percentage of error. The Hay method [9] is comparable to the equation G/Gext = a + b(n/N) for global radiation, but for diffuse radiation, the equation D/Gext = a + b (n/N) is superior to the Hay method. The correlations for global and diffuse radiation are G/Gext = 0.3156 + 0.4520(n/N) and D/Gext = 0.3616 − 0.2123 (n/N), respectively.

Prediction of global solar radiation from bright sunshine hours and other meteorological data

Three existing empirical relations which predict global radiation from bright sunshine hours and meteorological parameters, were tried for 14 Indian stations where all relevant data was available. A large amount of error (±50%) was found. So a new empirical relation was established between global radiation and meteorological parameters. The new relation predicted the insolation within a ±10% error limit in most cases. Global radiation dependence on ambient temperature and relative humidity was introduced through atmosperic water content per unit volume. The relation is WAT = RH(4.7923+0.3647×T+0.0055×T2+0.0003×T3)G = Gext(0.414+0.400×SS-0.0055×WAT)SS = SZ

Application of a novel bacterial consortium for mineralization of sulphonated aromatic amines.

A novel bacterial consortium (TJ-2) for mineralization of aromatic amines resulting from decolorization of azo dyes was developed. Three bacterial strains were identified as Pseudomonas pseudoalcaligenes (TJ-21,EU072476), Pseudomonas citronellolis (TJ-22,EU072477) and Pseudomonas testosterone (TJ-23,EU072477) by 16S rRNA gene sequence analysis. Aromatic amine mineralization under aerobic conditions was observed to be significantly higher with the consortium as compared to pure strains indicating complementary interactions among these strains. It was observed that more than 90% mineralization of aromatic amines was achieved within 18h for different initial aromatic amines concentrations. It was also observed that aromatic amine mineralization depends upon the structure of aromatic amine. Para- and meta-hydroxy substituted aromatic amine were easily mineralized as compared to ortho-substituted which undergoes autoxidation when exposed to oxygen. The consortium was capable of mineralizing other aromatic amines, thus, conferring the possibility of application of TJ-2 for the treatment of industrial wastewaters containing aromatic amines.

On‐line optimization of free radical bulk polymerization reactors in the presence of equipment failure

An on-line optimizing control scheme has been developed for bulk polymerization of free radical systems. The effects of random errors, as well as one kind of a major disturbance (heating system failure), have been studied. A model-based, inferential state estimation scheme was incorporated to estimate, on-line, the parameters of the model (and thereby, the monomer conversion and molecular weight of the polymer) using experimental data on temperature and viscosity. A sequential quadratic programming technique was used for this purpose. A major disturbance, such as heating system failure, leads to a deteriorated final product unless an on-line optimal temperature trajectory (history) is recomputed and implemented on the reactor. Genetic algorithm was used for this purpose. It has been found that, if the “sensing” of the major temperature deviation from the optimal value and rectification of the heating system is achieved well in advance of the onset of the Trommsdroff effect, use of a reoptimized temperature history is sufficient to produce the desired product without significantly altering reaction time. However, if such a disturbance occurs late, a single-shot intermediate addition of an optimal amount of initiator needs to be used in addition to changing the temperature history to produce polymers having the desired properties in the minimum reaction time. Other types of failures can similarly be handled using the methodology developed.

Development of a software tool and criteria evaluation for efficient design of small interfering RNA

RNA interference can be used as a tool for gene silencing mediated by small interfering RNAs (siRNA). The critical step in effective and specific RNAi processing is the selection of suitable constructs. Major design criteria, i.e., Reynoldss design rules, thermodynamic stability, internal repeats, immunostimulatory motifs were emphasized and implemented in the siRNA design tool. The tool provides thermodynamic stability score, GC content and a total score based on other design criteria in the output. The viability of the tool was established with different datasets. In general, the siRNA constructs produced by the tool had better thermodynamic score and positional properties. Comparable thermodynamic scores and better total scores were observed with the existing tools. Moreover, the results generated had comparable off-target silencing effect. Criteria evaluations with additional criteria were achieved in WEKA.

Calculation of appropriate size fixed sunshade overhangs over windows of different orientations

Abstract Following an earlier developed mathematical model [E. Shaviv, Building Int. 8 , 12(1975)], appropriate sizes of sunshade overhangs over windows of different orientations have been calculated so that no direct sun radiation penetrates through them for a period from 22 March to 22 September at New Delhi (latitude 28°35′N). Calculations have also been performed for total energy penetration through various windows of fixed size in different months of the year.

Multiobjective Optimization Using Genetic Algorithm

Abstract Genetic algorithm (GA) is among the more popular evolutionary optimization techniques. Its multiobjective (MO) versions are useful for solving industrial problems that are more meaningful and relevant. Usually, one obtains sets of several equally good (nondominated) optimal solutions for such cases, referred to as Pareto sets. One of the MOGA algorithms is the elitist n ondominated s orting g enetic a lgorithm (NSGA-II). Unfortunately, most MOGA codes, including NSGA-II, are quite slow when applied to real-life problems and several bio-mimetic adaptations have been developed to improve their rates of convergence. Some of these are described in detail. A few chemical engineering examples involving two or three noncommensurate objective functions are described. These include heat exchanger networks, industrial catalytic reactors for the manufacture of maleic anhydride and phthalic anhydride, industrial third stage polyester reactors, LDPE reactors with multiple injections of initiator, an industrial semibatch nylon-6 reactor, etc. A more compute-intense problem in bio-informatics (clustering of data from cDNA microarray experiments) is also discussed. Some very recent bio-mimetic adaptations of NSGA-II that hold promise for greatly improved rates of convergence to the optimal solutions are also presented.

Cost—benefit ratio of triple pass solar air heaters

Abstract In the present study, theoretical models for three pass solar air heaters with single and double cover have been developed, and the effects of depths of inlet (D1), intermediate (D2) and outlet (D3) air ducts, length (L) and air mass flow rate ( m ) on the ratio of annual cost (AC) and annual energy gain (AEG) have been investigated. The performances of these air heaters are compared with those of single pass air heaters with no cover, single and double covers and two pass air heaters with single and double covers. The results are presented in the form of various design curves which will help manufacturers select appropriate designs according to utility.